/* =============================================
   在线视频学习系统 — study.tlipoca.wiki
   暗黑玻璃拟态主题（与主站 tlipoca.wiki 保持一致）
   ============================================= */

/* ---------- 0. CSS 变量 ---------- */
:root {
    --color-bg: #080613;
    --color-surface: #120e23;
    --color-surface-alt: #191530;
    --color-surface-elevated: rgba(20, 16, 36, 0.82);
    --color-primary: #ab76e8;
    --color-primary-glow: rgba(171, 118, 232, 0.26);
    --color-secondary: #d4a24c;
    --color-accent: #e44d62;
    --color-accent-deep: #a0113a;
    --color-success: #22c55e;
    --color-warning: #f59e0b;
    --color-text: #edf2ff;
    --color-text-muted: #9ba7c4;
    --color-border: rgba(255, 255, 255, 0.1);
    --color-border-strong: rgba(171, 118, 232, 0.22);
    --glass-bg: rgba(18, 14, 35, 0.62);
    --glass-bg-strong: rgba(20, 16, 36, 0.82);
    --glass-blur: 12px;
    --glass-shadow: 0 18px 48px rgba(4, 8, 20, 0.28);
    --font-sans: 'Noto Sans SC', 'Microsoft YaHei', 'PingFang SC', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --nav-height: 60px;
    --radius: 18px;
    --radius-sm: 12px;
    --transition: cubic-bezier(0.22, 1, 0.36, 1);

    /* ---- 液态玻璃层级 ---- */
    --glass-bg-subtle: rgba(18, 14, 35, 0.42);
    --glass-bg-float: rgba(18, 14, 35, 0.88);
    --glass-blur-heavy: 18px;
    --glass-blur-light: 6px;
    --glass-border: rgba(255,255,255,0.12);
    --glass-border-high: rgba(255,255,255,0.22);
    --glass-glow-primary: 0 0 30px rgba(171,118,232,0.18);
    --glass-glow-accent: 0 0 24px rgba(228,77,98,0.15);

    /* ---- 动画缓动 ---- */
    --ease-spring: cubic-bezier(.34,1.56,.64,1);
    --ease-liquid: cubic-bezier(.22,1,.36,1);
    --ease-smooth: cubic-bezier(.4,0,.2,1);
    --duration-fast: 180ms;
    --duration-normal: 350ms;
    --duration-slow: 550ms;
}

/* ---------- 1. 基础重置 ---------- */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; scrollbar-width: thin; scrollbar-color: #4c1d95 var(--color-bg); }
html::-webkit-scrollbar { width: 8px; }
html::-webkit-scrollbar-track { background: var(--color-bg); }
html::-webkit-scrollbar-thumb { background: #4c1d95; border-radius: 4px; }

body {
    font-family: var(--font-sans);
    color: var(--color-text);
    line-height: 1.7;
    overflow-x: hidden;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    position: relative;
    z-index: 0;
}

/* 固定背景层 — 用伪元素替代 background-attachment:fixed
   避免 Chrome 合成层 bug 导致 backdrop-filter 失效 */
body::before {
    content: '';
    position: fixed;
    inset: 0;
    z-index: -1;
    background: var(--color-bg);
    background-image:
        linear-gradient(180deg, rgba(8,6,19,0.94) 0%, rgba(8,6,19,0.99) 100%),
        radial-gradient(circle at 14% 18%, rgba(212,162,76,0.12) 0%, transparent 34%),
        radial-gradient(circle at 82% 16%, rgba(171,118,232,0.18) 0%, transparent 36%),
        radial-gradient(circle at 50% 100%, rgba(228,77,98,0.08) 0%, transparent 42%);
}
}
a { color: inherit; text-decoration: none; }
img { max-width: 100%; height: auto; display: block; }
ul { list-style: none; }
button { cursor: pointer; font-family: var(--font-sans); }
input, select, textarea { font-family: var(--font-sans); }

/* ---------- 2. 导航栏 — 液态玻璃增强 ---------- */
.site-nav {
    position: sticky; top: 0; z-index: 100;
    height: var(--nav-height);
    background: linear-gradient(135deg, rgba(8,12,24,0.88) 0%, rgba(18, 14, 35,0.84) 52%, rgba(20, 16, 36,0.9) 100%);
    backdrop-filter: blur(var(--glass-blur-heavy)) saturate(150%);
    -webkit-backdrop-filter: blur(var(--glass-blur-heavy)) saturate(150%);
    border-bottom: 1px solid var(--glass-border);
    box-shadow: 0 14px 36px rgba(5, 8, 18, 0.2), 0 1px 0 rgba(255,255,255,.04) inset;
}
/* 底部渐变发光分割线 + 液态流动 */
.site-nav::after {
    content: '';
    position: absolute;
    left: 0;
    right: 0;
    bottom: 0;
    height: 2px;
    background: linear-gradient(90deg,
        transparent 0%,
        rgba(212,162,76,0.12) 20%,
        rgba(171,118,232,0.35) 50%,
        rgba(14,165,233,0.25) 80%,
        transparent 100%);
    animation: glass-shift-gradient 6s ease-in-out infinite;
    background-size: 200% 100%;
}
.nav-inner {
    max-width: 1280px; margin: 0 auto; height: 100%;
    display: flex; align-items: center; justify-content: space-between;
    padding: 0 24px; gap: 18px;
}
.nav-logo { display: flex; align-items: center; gap: 10px; flex-shrink: 0; }
.nav-logo .logo-icon { font-size: 24px; }
.nav-logo span { font-size: 16px; font-weight: 700; color: #fff; white-space: nowrap; }
/* 导航链接容器 — 液态玻璃滑动浮层 */
.nav-links {
    display: flex; gap: 4px; align-items: center;
    position: relative;
    --pill-left: 0px;
    --pill-width: 0px;
    --pill-opacity: 0;
}
/* 液态玻璃浮层 — 跟随 hover/active 滑动 */
/* 初始无过渡，防止页面切换时从左边飞入 */
.nav-links::after {
    content: '';
    position: absolute;
    top: 0; bottom: 0;
    left: var(--pill-left, 0px);
    width: var(--pill-width, 0px);
    border-radius: 999px;
    background: linear-gradient(135deg, rgba(171,118,232,.18), rgba(212,162,76,.10));
    border: 1px solid rgba(255,255,255,.15);
    box-shadow: 0 2px 14px rgba(171,118,232,.12), inset 0 1px 0 rgba(255,255,255,.08);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    opacity: var(--pill-opacity, 0);
    transition: none;
    z-index: 0; pointer-events: none;
}
/* 浮层就绪后开启液态滑动过渡 */
.nav-links[data-pill-ready]::after {
    transition:
        left .45s cubic-bezier(.34,1.56,.64,1),
        width .45s cubic-bezier(.34,1.56,.64,1),
        opacity .3s var(--ease-liquid);
}
.nav-links a {
    padding: 7px 14px; border-radius: 999px; font-size: 14px;
    color: var(--color-text-muted);
    transition: color var(--duration-normal) var(--ease-liquid),
                transform var(--duration-normal) var(--ease-spring);
    white-space: nowrap;
    border: 1px solid transparent;
    position: relative;
    z-index: 1;
    background: transparent;
}
.nav-links a:hover {
    color: #fff;
    border-color: transparent;
    background: transparent;
    transform: translateY(-2px);
    box-shadow: none;
}
.nav-links a.active {
    color: #fff;
    background: transparent;
    border-color: transparent;
}
.nav-right { display: flex; align-items: center; gap: 12px; flex-shrink: 0; }
.nav-user {
    display: flex; align-items: center; gap: 8px;
    padding: 6px 14px; border-radius: 999px;
    background: rgba(255,255,255,.045); border: 1px solid var(--color-border);
    font-size: 13px; color: var(--color-text-muted); text-decoration: none;
    box-shadow: inset 0 1px 0 rgba(255,255,255,.04);
    transition: background .2s, border-color .2s, color .2s;
}
.nav-user:hover { background: rgba(255,255,255,.08); border-color: rgba(255,255,255,.14); color: #fff; }
.nav-user .role-badge {
    padding: 1px 8px; border-radius: 6px; font-size: 11px; font-weight: 600;
}
.badge-student { background: rgba(34,197,94,.15); color: #22c55e; }
.badge-teacher { background: rgba(171, 118, 232,.15); color: #a855f7; }
.badge-admin { background: rgba(255,107,107,.15); color: #ff6b6b; }
.nav-login-btn {
    padding: 8px 18px; border-radius: 999px; font-size: 13px; font-weight: 600;
    color: #fff; background: linear-gradient(135deg, #d43d55, #a0113a);
    transition: transform .2s, box-shadow .3s, filter .3s; border: none;
    box-shadow: 0 10px 24px rgba(190,18,60,.22);
}
.nav-login-btn:hover { transform: translateY(-1px); box-shadow: 0 14px 30px rgba(190,18,60,.3); filter: brightness(1.02); }
.btn-logout {
    padding: 6px 12px; border-radius: 999px; font-size: 12px;
    background: rgba(255,255,255,.06); border: 1px solid var(--color-border);
    color: var(--color-text-muted); transition: all .2s;
}
.btn-logout:hover { color: var(--color-accent); border-color: var(--color-accent); }
.nav-hamburger { display: none; flex-direction: column; gap: 5px; cursor: pointer; padding: 4px; z-index: 1001; }
.nav-hamburger span { width: 24px; height: 2px; background: #fff; border-radius: 2px; transition: all .3s; }

/* ---------- 3. 页面容器 ---------- */
.page-container { max-width: 1280px; margin: 0 auto; padding: 40px 24px 72px; width: 100%; flex: 1; }
.page-header { margin-bottom: 28px; }
.page-header h1 { font-size: 28px; font-weight: 800; color: #fff; margin-bottom: 8px; }
.page-header p { color: var(--color-text-muted); font-size: 15px; }

/* ---------- 4. 卡片 ---------- */
/* 液态玻璃卡片 — 黄金标准 */
.glass-card,
.card {
    padding: 24px; border-radius: var(--radius);
    background: linear-gradient(145deg, rgba(255,255,255,.06) 0%, rgba(171, 118, 232,.03) 100%), var(--glass-bg);
    backdrop-filter: blur(var(--glass-blur)) saturate(135%);
    -webkit-backdrop-filter: blur(var(--glass-blur)) saturate(135%);
    border: 1px solid var(--glass-border);
    box-shadow: var(--glass-shadow);
    transition: transform var(--duration-normal) var(--ease-liquid),
                box-shadow var(--duration-normal) var(--ease-liquid),
                border-color var(--duration-normal) var(--ease-liquid);
}
.glass-card:hover,
.card:hover {
    transform: translateY(-4px);
    border-color: var(--glass-border-high);
    box-shadow: var(--glass-shadow), var(--glass-glow-primary);
}
.card-static { composes: card; }
.card-static:hover { transform: none; }

/* ---------- 5. 课程卡片网格 ---------- */
.course-grid {
    display: grid; grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 20px;
}
.course-card {
    border-radius: var(--radius); overflow: hidden;
    background: linear-gradient(160deg, rgba(255,255,255,.06) 0%, rgba(124,58,237,.03) 100%), var(--glass-bg);
    border: 1px solid var(--color-border);
    box-shadow: var(--glass-shadow);
    transition: transform .2s, box-shadow .2s; cursor: pointer;
}
.course-card:hover { transform: translateY(-4px); box-shadow: 0 24px 48px rgba(4, 8, 20, 0.3); }
.course-card .cover {
    height: 160px; background: linear-gradient(135deg, #101726, #26255d 60%, #1f3f74 100%);
    display: flex; align-items: center; justify-content: center;
    font-size: 48px; position: relative; overflow: hidden;
}
.course-card .cover::after {
    content: ''; position: absolute; inset: 0;
    background: linear-gradient(transparent 50%, rgba(10,10,26,.8));
}
.course-card .info { padding: 16px; }
.course-card .info h3 { font-size: 16px; font-weight: 700; color: #fff; margin-bottom: 6px;
    overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.course-card .info .meta {
    display: flex; gap: 12px; font-size: 12px; color: var(--color-text-muted); margin-bottom: 8px;
}
.course-card .info .desc {
    font-size: 13px; color: var(--color-text-muted); line-height: 1.5;
    display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; overflow: hidden;
}
.course-card .category-tag {
    position: absolute; top: 12px; left: 12px; z-index: 1;
    padding: 3px 10px; border-radius: 6px; font-size: 11px; font-weight: 600;
    background: rgba(171, 118, 232,.8); color: #fff;
}

/* ---------- 6. 按钮 ---------- */
.btn {
    display: inline-flex; align-items: center; gap: 6px;
    padding: 9px 20px; border-radius: 12px; font-size: 14px; font-weight: 600;
    border: none; transition: all .2s; cursor: pointer;
}
.btn-primary { background: linear-gradient(135deg, #ab76e8, #8a3fd6); color: #fff; }
.btn-primary:hover { box-shadow: 0 14px 30px rgba(171, 118, 232,.28); transform: translateY(-1px); }
.btn-danger { background: linear-gradient(135deg, #e0444c, #b91c1c); color: #fff; }
.btn-danger:hover { box-shadow: 0 14px 30px rgba(239,68,68,.22); }
.btn-success { background: linear-gradient(135deg, #22c55e, #16a34a); color: #fff; }
.btn-success:hover { box-shadow: 0 14px 30px rgba(34,197,94,.22); }
.btn-outline {
    background: rgba(255,255,255,.03); color: var(--color-text);
    border: 1px solid var(--color-border);
}
.btn-outline:hover { background: rgba(171, 118, 232,.08); border-color: var(--color-border-strong); color: #fff; }
.btn-sm { padding: 5px 14px; font-size: 12px; border-radius: 8px; }
.btn-ghost {
    background: rgba(255,255,255,.04); color: var(--color-text-muted);
    border: 1px solid var(--color-border);
}
.btn-ghost:hover { color: #fff; background: rgba(255,255,255,.08); }
.btn:disabled { opacity: .55; cursor: not-allowed; box-shadow: none; transform: none; }
.btn-glow {
    background: linear-gradient(135deg, #a855f7, #7c3aed);
    color: #fff;
    box-shadow: 0 0 20px rgba(168,85,247,.35);
    animation: btn-glow-pulse 2s ease-in-out infinite;
}
.btn-glow:hover {
    box-shadow: 0 0 30px rgba(168,85,247,.5);
    transform: translateY(-2px);
}
@keyframes btn-glow-pulse {
    0%, 100% { box-shadow: 0 0 20px rgba(168,85,247,.35); }
    50%      { box-shadow: 0 0 30px rgba(168,85,247,.5); }
}
.btn-accent {
    background: linear-gradient(135deg, #f97316, #ea580c);
    color: #fff;
}
.btn-accent:hover { box-shadow: 0 14px 30px rgba(249,115,22,.28); transform: translateY(-1px); }

/* 行内编辑（目录结构中双击标题即改） */
.inline-edit {
    cursor: text;
    border-bottom: 1px dashed transparent;
    transition: border-color .15s ease;
    padding: 2px 4px; margin: -2px -4px;
    border-radius: 4px;
}
.inline-edit:hover {
    border-bottom-color: var(--color-primary);
    background: rgba(59,130,246,.05);
}
.inline-edit-input {
    outline: none;
}

/* 行内创建（+ 新增章节 / + 小节 替换弹窗） */
.inline-create-row {
    display: flex; align-items: center; gap: 8px;
    padding: 8px 0; margin: 8px 0;
}
.inline-create-row .inline-create-input {
    padding: 8px 14px;
    border-radius: 8px;
    font-size: 14px;
}

/* ---------- 7. 表单 ---------- */
.form-group { margin-bottom: 18px; }
.form-group label { display: block; font-size: 13px; font-weight: 600; color: var(--color-text-muted); margin-bottom: 6px; }
.form-control {
    width: 100%; padding: 10px 14px; border-radius: 10px;
    background: rgba(255,255,255,.04); border: 1px solid var(--color-border);
    color: var(--color-text); font-size: 14px; outline: none; transition: border-color .2s;
}
.form-control:focus { border-color: rgba(212, 162, 76,.28); box-shadow: 0 0 0 4px rgba(212, 162, 76,.12); }
.form-control::placeholder { color: rgba(255,255,255,.25); }
textarea.form-control { resize: vertical; min-height: 80px; }
select.form-control {
    appearance: none;
    color-scheme: dark;
    background-color: rgba(9,12,24,.92);
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath fill='%239a9ab0' d='M6 8L1 3h10z'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 12px center;
    padding-right: 32px;
}
select.form-control option,
select.form-control optgroup {
    background: #0b1222;
    color: #eef2ff;
}

/* file input 自定义样式 */
input[type="file"].form-control {
    padding: 8px 12px;
    color: var(--color-text-muted);
    cursor: pointer;
}
input[type="file"].form-control::file-selector-button {
    padding: 6px 16px;
    margin-right: 12px;
    border-radius: 8px;
    border: 1px solid var(--color-border);
    background: rgba(171,118,232,.15);
    color: #d7c9f0;
    font-size: 13px; font-weight: 600;
    cursor: pointer;
    transition: background .2s, border-color .2s;
}
input[type="file"].form-control::file-selector-button:hover {
    background: rgba(171,118,232,.28);
    border-color: rgba(171,118,232,.4);
}

/* datetime-local 清除按钮行 */
.datetime-input-row {
    display: flex; gap: 6px; align-items: center;
}
.datetime-input-row .form-control {
    flex: 1;
}
.datetime-clear {
    flex-shrink: 0; width: 32px; height: 32px; padding: 0;
    display: flex; align-items: center; justify-content: center;
    border-radius: 8px; font-size: 14px; line-height: 1;
}

/* ---------- 7.5. 返回顶部 ---------- */
.back-to-top {
    position: fixed; bottom: 32px; right: 32px;
    width: 48px; height: 48px; border-radius: 50%;
    display: flex; align-items: center; justify-content: center;
    cursor: pointer; font-size: 22px; color: rgba(255,255,255,.85);
    background: rgba(18,14,35,.72);
    backdrop-filter: blur(14px) saturate(135%);
    -webkit-backdrop-filter: blur(14px) saturate(135%);
    border: 1px solid var(--color-border);
    box-shadow: 0 8px 32px rgba(0,0,0,.35), inset 0 1px 0 rgba(255,255,255,.08);
    opacity: 0; visibility: hidden;
    transition: opacity .4s ease, visibility .4s, transform .4s ease;
    transform: translateY(12px) scale(.85);
    z-index: 1100;
}
.back-to-top.show { opacity: 1; visibility: visible; transform: translateY(0) scale(1); }
.back-to-top:hover { background: rgba(104,88,152,.22); transform: translateY(-4px) scale(1.06); box-shadow: 0 12px 36px rgba(104,88,152,.18), inset 0 1px 0 rgba(255,255,255,.12); }

/* ---------- 8. 表格 — 液态玻璃 ---------- */
.table-wrap {
    overflow-x: auto; border-radius: var(--radius);
    border: 1px solid var(--glass-border);
    background: var(--glass-bg-subtle);
    backdrop-filter: blur(6px);
    -webkit-backdrop-filter: blur(6px);
}
table { width: 100%; border-collapse: collapse; }
th { padding: 12px 16px; text-align: left; font-size: 12px; font-weight: 700; color: var(--color-text-muted); text-transform: uppercase; letter-spacing: .5px; background: rgba(255,255,255,.04); border-bottom: 1px solid var(--glass-border); }
td { padding: 12px 16px; font-size: 14px; border-bottom: 1px solid var(--glass-border); }
tr:hover td {
    background: rgba(255,255,255,.03);
    backdrop-filter: blur(4px);
    -webkit-backdrop-filter: blur(4px);
}

/* ---------- 9. 统计卡片 ---------- */
.stats-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 16px; margin-bottom: 28px; }
.stat-card {
    padding: 20px; border-radius: var(--radius);
    background: var(--glass-bg); border: 1px solid var(--color-border);
}
.stat-card .label { font-size: 12px; color: var(--color-text-muted); margin-bottom: 4px; text-transform: uppercase; letter-spacing: .5px; }
.stat-card .value { font-size: 28px; font-weight: 800; color: #fff; }
.stat-card .value .unit { font-size: 14px; font-weight: 400; color: var(--color-text-muted); margin-left: 4px; }

/* ---------- 10. 视频播放器 ---------- */
.video-wrapper {
    position: relative; border-radius: var(--radius); overflow: hidden;
    background: #000; margin-bottom: 20px;
}
.video-wrapper video { width: 100%; display: block; max-height: 70vh; }
.video-list { display: flex; flex-direction: column; gap: 4px; }
.video-item {
    display: flex; align-items: center; gap: 12px;
    padding: 12px 16px; border-radius: 10px; cursor: pointer;
    transition: background .2s; border: 1px solid transparent;
}
.video-item:hover { background: rgba(255,255,255,.04); }
.video-item.active { background: rgba(171, 118, 232,.1); border-color: rgba(171, 118, 232,.3); }
.video-item .idx { width: 28px; height: 28px; border-radius: 8px; display: flex; align-items: center; justify-content: center; font-size: 12px; font-weight: 700; background: rgba(255,255,255,.06); color: var(--color-text-muted); flex-shrink: 0; }
.video-item.active .idx { background: var(--color-primary); color: #fff; }
.video-item .v-title { flex: 1; font-size: 14px; }
.video-item .v-duration { font-size: 12px; color: var(--color-text-muted); }
.video-item .v-status { font-size: 16px; }

.study-catalog {
    border: 1px solid var(--color-border);
    border-radius: 18px;
    overflow: hidden;
    background: linear-gradient(180deg, rgba(255,255,255,.06) 0%, rgba(255,255,255,.02) 100%), var(--glass-bg-strong);
    box-shadow: var(--glass-shadow);
}
.study-catalog-head {
    display: grid;
    grid-template-columns: minmax(0, 1fr) 92px;
    gap: 16px;
    align-items: center;
    padding: 12px 18px;
    border-bottom: 1px solid rgba(255,255,255,.08);
    background: linear-gradient(135deg, rgba(255,255,255,.05), rgba(171, 118, 232,.06));
    font-size: 12px;
    font-weight: 800;
    letter-spacing: .08em;
    text-transform: uppercase;
    color: #8ea0c6;
}
.study-catalog-head span:last-child {
    text-align: right;
}
.study-catalog-body {
    position: relative;
}
.study-catalog-unit {
    border-bottom: 1px solid rgba(255,255,255,.06);
}
.study-catalog-unit:last-child {
    border-bottom: none;
}
.study-catalog-unit.is-collapsed .study-catalog-children {
    display: none;
}
.study-catalog-unit.is-collapsed .study-catalog-node-arrow {
    transform: rotate(-45deg);
    margin-top: 4px;
}
.study-catalog-node {
    width: 100%;
    display: grid;
    grid-template-columns: auto minmax(0, 1fr) auto auto;
    gap: 14px;
    align-items: center;
    padding: 14px 18px;
    border: 0;
    background: transparent;
    color: inherit;
    text-align: left;
    cursor: pointer;
    transition: background .2s ease;
}
.study-catalog-node:hover {
    background: rgba(255,255,255,.04);
}
.study-catalog-index {
    width: 32px;
    height: 32px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    border-radius: 999px;
    border: 1px solid rgba(58,139,255,.35);
    background: rgba(58,139,255,.12);
    color: #dbeafe;
    font-size: 13px;
    font-weight: 800;
    flex-shrink: 0;
}
.study-catalog-index--course {
    border-color: rgba(251,191,36,.28);
    background: rgba(251,191,36,.12);
    color: #fde68a;
}
.study-catalog-node-copy {
    min-width: 0;
    display: flex;
    flex-direction: column;
    gap: 4px;
}
.study-catalog-node-title {
    font-size: 15px;
    font-weight: 700;
    color: #fff;
    white-space: normal;
    overflow-wrap: anywhere;
    line-height: 1.45;
}
.study-catalog-node-summary {
    font-size: 12px;
    color: var(--color-text-muted);
    white-space: normal;
    overflow-wrap: anywhere;
    line-height: 1.55;
}
.study-catalog-node-meta {
    font-size: 12px;
    font-weight: 700;
    color: #8ea0c6;
    white-space: nowrap;
}
.study-catalog-node-arrow {
    width: 10px;
    height: 10px;
    border-right: 2px solid rgba(255,255,255,.55);
    border-bottom: 2px solid rgba(255,255,255,.55);
    transform: rotate(45deg);
    transition: transform .2s ease;
    margin-top: -4px;
}
.study-catalog-children {
    background: rgba(8, 6, 19, 0.72);
}
.study-catalog-row {
    width: 100%;
    display: grid;
    grid-template-columns: minmax(0, 1fr) 92px;
    gap: 16px;
    align-items: center;
    padding: 12px 18px 12px 64px;
    border: 0;
    border-top: 1px solid rgba(255,255,255,.04);
    background: transparent;
    color: inherit;
    text-align: left;
    cursor: pointer;
    transition: background .2s ease, box-shadow .2s ease;
}
.study-catalog-row:hover {
    background: rgba(255,255,255,.04);
}
.study-catalog-row.active {
    background: linear-gradient(135deg, rgba(212, 162, 76,.12), rgba(171, 118, 232,.08));
    box-shadow: inset 3px 0 0 #60a5fa;
}
.study-catalog-row--section {
    padding-left: 102px;
}
.study-catalog-row-main {
    min-width: 0;
    display: flex;
    align-items: flex-start;
    gap: 12px;
}
.study-catalog-row-icon {
    width: 22px;
    height: 22px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    margin-top: 1px;
    border-radius: 999px;
    flex-shrink: 0;
    font-size: 11px;
    font-weight: 800;
}
.study-catalog-row-icon--video {
    background: rgba(59,130,246,.14);
    color: #bfdbfe;
}
.study-catalog-row-icon--text {
    background: rgba(251,191,36,.14);
    color: #fde68a;
}
.study-catalog-row-copy {
    min-width: 0;
    display: flex;
    flex-direction: column;
    gap: 4px;
}
.study-catalog-row-title {
    font-size: 14px;
    font-weight: 600;
    color: #f8fafc;
    white-space: normal;
    overflow-wrap: anywhere;
    line-height: 1.45;
}
.study-catalog-row-meta {
    font-size: 12px;
    color: var(--color-text-muted);
    white-space: normal;
    overflow-wrap: anywhere;
    line-height: 1.55;
}
.study-catalog-status {
    justify-self: end;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 72px;
    padding: 4px 10px;
    border-radius: 999px;
    font-size: 12px;
    font-weight: 700;
    white-space: nowrap;
}
.study-catalog-status--done {
    background: rgba(34,197,94,.14);
    color: #86efac;
}
.study-catalog-status--progress {
    background: rgba(59,130,246,.14);
    color: #bfdbfe;
}
.study-catalog-status--idle {
    background: rgba(148,163,184,.12);
    color: #cbd5e1;
}
.study-catalog-status--text {
    background: rgba(251,191,36,.14);
    color: #fde68a;
}
.study-catalog-section-block {
    border-top: 1px solid rgba(255,255,255,.04);
}
.study-catalog-section-head {
    display: grid;
    grid-template-columns: auto minmax(0, 1fr) auto;
    gap: 14px;
    align-items: center;
    padding: 12px 18px 12px 64px;
    background: rgba(255,255,255,.02);
}
.study-catalog-section-code {
    font-size: 12px;
    font-weight: 800;
    color: #60a5fa;
}
.study-catalog-section-copy {
    min-width: 0;
    display: flex;
    flex-direction: column;
    gap: 4px;
}
.study-catalog-section-title {
    font-size: 14px;
    font-weight: 700;
    color: #fff;
    white-space: normal;
    overflow-wrap: anywhere;
    line-height: 1.45;
}
.study-catalog-section-summary {
    font-size: 12px;
    color: var(--color-text-muted);
    white-space: normal;
    overflow-wrap: anywhere;
    line-height: 1.55;
}
.study-catalog-empty-row {
    padding: 12px 18px 12px 102px;
    border-top: 1px solid rgba(255,255,255,.04);
    font-size: 12px;
    color: var(--color-text-muted);
}

.lesson-reader {
    min-height: 320px; padding: 28px;
    background: linear-gradient(180deg, rgba(255,255,255,.04) 0%, rgba(171, 118, 232,.03) 100%);
}
.lesson-reader h2 {
    margin-bottom: 14px; font-size: 28px; line-height: 1.3; color: #fff;
}
.lesson-reader-summary {
    margin-bottom: 20px; color: var(--color-text-muted); line-height: 1.8;
}
.lesson-reader-body {
    white-space: pre-wrap; word-break: break-word;
    font-size: 15px; line-height: 1.9; color: var(--color-text);
}

.structure-manager { display: flex; flex-direction: column; gap: 16px; }
.structure-toolbar {
    display: flex; align-items: center; justify-content: space-between;
    gap: 16px; flex-wrap: wrap;
}
.structure-root,
.structure-node {
    padding: 16px; border-radius: 14px;
    background: var(--glass-bg-subtle);
    backdrop-filter: blur(6px);
    -webkit-backdrop-filter: blur(6px);
    border: 1px solid var(--glass-border);
    transition: border-color var(--duration-fast) var(--ease-liquid),
                box-shadow var(--duration-fast) var(--ease-liquid);
}
.structure-node:hover {
    border-color: var(--glass-border-high);
    box-shadow: 0 0 16px rgba(171,118,232,.08);
}
.structure-node-head {
    display: flex; align-items: flex-start; justify-content: space-between;
    gap: 16px; flex-wrap: wrap; margin-bottom: 12px;
}
.structure-chapter-list,
.structure-section-list,
.structure-subgroup { display: flex; flex-direction: column; gap: 12px; }
.structure-content-list { display: flex; flex-direction: column; gap: 8px; }
.structure-content-item {
    display: flex; align-items: center; justify-content: space-between;
    gap: 12px; flex-wrap: wrap; padding: 12px 14px;
    border-radius: 10px;
    background: var(--glass-bg-subtle);
    border: 1px solid var(--glass-border);
    transition: border-color var(--duration-fast) var(--ease-liquid);
}
.structure-content-item:hover {
    border-color: var(--glass-border-high);
}

.quiz-scope-group { display: flex; flex-direction: column; gap: 12px; margin-bottom: 18px; }
.quiz-scope-group-title {
    font-size: 13px; font-weight: 800; color: #fff;
    padding-left: 4px; letter-spacing: .3px;
}

/* ---------- 11. 进度条 ---------- */
.progress-bar { height: 6px; border-radius: 3px; background: rgba(255,255,255,.08); overflow: hidden; }
.progress-bar .fill { height: 100%; border-radius: 3px; background: linear-gradient(90deg, var(--color-primary), #c084fc); transition: width .3s; }

/* ---------- 12. 标签 & 徽章 ---------- */
.tag {
    display: inline-block; padding: 3px 10px; border-radius: 6px;
    font-size: 11px; font-weight: 600;
}
.tag-published { background: rgba(34,197,94,.15); color: #22c55e; }
.tag-draft { background: rgba(245,158,11,.15); color: #f59e0b; }
.tag-category { background: rgba(171, 118, 232,.15); color: #a855f7; }
.tag-info { background: rgba(212, 162, 76,.15); color: #60a5fa; }
.tag-warning { background: rgba(251,191,36,.15); color: #fbbf24; }
.badge-soft {
    display: inline-flex; align-items: center; justify-content: center;
    padding: 4px 10px; border-radius: 999px;
    background: rgba(255,255,255,.06); color: var(--color-text-muted);
    font-size: 12px; font-weight: 700;
}
/* ---------- AI 模型选择 — 液态玻璃分段胶囊 ---------- */
.model-pills {
    display: inline-flex; gap: 0;
    border-radius: 999px;
    background: rgba(128,128,128,0.06);
    border: 1px solid var(--color-border);
    padding: 3px;
    position: relative;
    --pill-left: 3px;
    --pill-width: 60px;
}
.model-pill {
    display: inline-flex; align-items: center; justify-content: center;
    padding: 7px 20px; border-radius: 999px; border: none;
    background: transparent; color: var(--color-text-muted);
    font-size: 13px; font-weight: 600; cursor: pointer;
    transition: color .35s ease;
    position: relative; z-index: 1;
    user-select: none;
}
.model-pill:hover {
    color: var(--color-text);
}
.model-pill.active {
    color: #fff;
    transition: color .15s ease;
}
/* 液态玻璃浮层 — 从容器 padding 边缘起，精确覆盖当前选项 */
.model-pills::after {
    content: '';
    position: absolute;
    top: 3px; bottom: 3px;
    left: var(--pill-left, 3px);
    width: var(--pill-width, 60px);
    border-radius: 999px;
    background: rgba(14,165,233,0.25);
    border: 1px solid rgba(255,255,255,0.25);
    box-shadow:
        0 2px 12px rgba(14,165,233,0.25),
        inset 0 1px 0 rgba(255,255,255,0.2);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    opacity: var(--pill-opacity, 0);
    transition:
        left .4s cubic-bezier(.34,1.56,.64,1),
        width .4s cubic-bezier(.34,1.56,.64,1),
        background .35s ease,
        box-shadow .35s ease,
        opacity .2s ease;
    z-index: 0; pointer-events: none;
}
/* 模型颜色 */
.model-pills[data-active="glm-4.7-flash"]::after {
    background: rgba(14,165,233,0.28);
    box-shadow: 0 2px 14px rgba(14,165,233,0.35), inset 0 1px 0 rgba(255,255,255,0.2);
    border-color: rgba(255,255,255,0.3);
}
.model-pills[data-active="deepseek-v4-flash"]::after {
    background: rgba(34,197,94,0.28);
    box-shadow: 0 2px 14px rgba(34,197,94,0.35), inset 0 1px 0 rgba(255,255,255,0.2);
    border-color: rgba(255,255,255,0.3);
}
.model-pills[data-active="deepseek-v4-pro"]::after {
    background: rgba(168,85,247,0.28);
    box-shadow: 0 2px 14px rgba(168,85,247,0.35), inset 0 1px 0 rgba(255,255,255,0.2);
    border-color: rgba(255,255,255,0.3);
}

/* ---------- 12.5 AI Thinking 流光动画 ---------- */
@keyframes ai-thinking-shimmer {
    0%   { background-position: -200% 0; }
    100% { background-position: 200% 0; }
}
@keyframes ai-pulse {
    0%, 100% { opacity: 0.4; transform: scale(0.95); }
    50%      { opacity: 1;   transform: scale(1.1);  }
}
@keyframes ai-fade-in {
    from { opacity: 0; transform: translateY(-8px); }
    to   { opacity: 1; transform: translateY(0); }
}

.ai-thinking-text {
    background: linear-gradient(
        90deg,
        var(--color-text-muted) 0%,
        #a855f7 40%,
        #22c55e 60%,
        var(--color-text-muted) 100%
    );
    background-size: 200% 100%;
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    animation: ai-thinking-shimmer 2.5s ease-in-out infinite;
}
.ai-pulse-dot {
    display: inline-block;
    width: 10px; height: 10px;
    border-radius: 50%;
    background: var(--color-primary);
    box-shadow: 0 0 8px var(--color-primary-glow);
    animation: glass-breath-glow 2s ease-in-out infinite;
    margin-right: 6px;
    vertical-align: middle;
}
.ai-status-bar {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 10px 14px;
    border-radius: var(--radius-sm);
    font-size: 13px;
    margin-top: 8px;
    backdrop-filter: blur(6px);
    -webkit-backdrop-filter: blur(6px);
    border: 1px solid var(--glass-border);
}
.ai-status-bar[data-tone="idle"] { background: var(--glass-bg-subtle); color: var(--color-text-muted); }
.ai-status-bar[data-tone="thinking"] { background: rgba(168,85,247,.08); color: #a855f7; border-color: rgba(168,85,247,.22); box-shadow: 0 0 14px rgba(168,85,247,.08); }
.ai-status-bar[data-tone="streaming"] { background: rgba(59,130,246,.08); color: #3b82f6; border: 1px solid rgba(59,130,246,.15); }
.ai-status-bar[data-tone="done"] { background: rgba(34,197,94,.08); color: #22c55e; border: 1px solid rgba(34,197,94,.15); }
.ai-status-bar[data-tone="error"] { background: rgba(239,68,68,.08); color: #ef4444; border: 1px solid rgba(239,68,68,.15); }
.ai-status-bar .ai-status-label { font-weight: 500; animation: ai-fade-in 0.3s ease-out; }

/* AI 模型选择器 — 快速切换栏 */
.ai-model-selector {
    display: flex;
    align-items: center;
    margin-top: 10px;
}
.ai-model-selector .model-pills {
    flex: 1;
}

/* Admin Debug Panel */
.ai-debug-panel {
    margin-top: 8px;
    border: 1px solid rgba(168,85,247,.2);
    border-radius: 8px;
    overflow: hidden;
}
.ai-debug-header {
    background: rgba(168,85,247,.08);
    padding: 6px 12px;
    font-size: 12px;
    color: #a855f7;
    cursor: pointer;
    user-select: none;
    display: flex;
    justify-content: space-between;
    align-items: center;
}
.ai-debug-header:hover { background: rgba(168,85,247,.14); }
.ai-debug-body {
    padding: 8px 12px;
    background: rgba(0,0,0,.25);
    font-family: "Cascadia Code", "Fira Code", "Consolas", monospace;
    font-size: 11px;
    line-height: 1.6;
    color: #ccc;
}
.ai-debug-body .debug-section {
    margin-bottom: 8px;
}
.ai-debug-body .debug-section:last-child { margin-bottom: 0; }
.ai-debug-body h5 {
    font-size: 11px;
    color: #888;
    margin: 0 0 2px 0;
    font-weight: 600;
}
.ai-debug-body pre {
    margin: 0;
    padding: 6px 8px;
    background: rgba(255,255,255,.03);
    border-radius: 4px;
    white-space: pre-wrap;
    word-break: break-word;
    max-height: 120px;
    overflow-y: auto;
}

/* =============================================
   12.8 液态玻璃可复用组件体系
   ============================================= */

/* ---- 玻璃面板 ---- */
.glass-panel {
    background: linear-gradient(180deg, rgba(255,255,255,.04) 0%, rgba(18,14,35,.72) 100%), var(--glass-bg-strong);
    backdrop-filter: blur(var(--glass-blur-heavy)) saturate(130%);
    -webkit-backdrop-filter: blur(var(--glass-blur-heavy)) saturate(130%);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius);
    box-shadow: var(--glass-shadow);
}

/* ---- 玻璃面板入场 ---- */
@keyframes glass-panel-enter {
    from { opacity: 0; transform: translateY(16px); }
    to   { opacity: 1; transform: translateY(0); }
}
.glass-panel-enter {
    animation: glass-panel-enter var(--duration-slow) var(--ease-liquid) both;
}

/* ---- 玻璃卡片交错入场 ---- */
@keyframes glass-card-enter {
    from { opacity: 0; transform: translateY(24px) scale(.96); }
    to   { opacity: 1; transform: translateY(0) scale(1); }
}
.glass-card-enter {
    animation: glass-card-enter var(--duration-slow) var(--ease-spring) both;
}
.glass-card-enter:nth-child(1) { animation-delay: 0ms; }
.glass-card-enter:nth-child(2) { animation-delay: 60ms; }
.glass-card-enter:nth-child(3) { animation-delay: 120ms; }
.glass-card-enter:nth-child(4) { animation-delay: 180ms; }
.glass-card-enter:nth-child(5) { animation-delay: 240ms; }
.glass-card-enter:nth-child(6) { animation-delay: 300ms; }

/* ---- 淡入微缩放 ---- */
@keyframes glass-fade-scale {
    from { opacity: 0; transform: scale(.94); }
    to   { opacity: 1; transform: scale(1); }
}

/* ---- 玻璃输入框 ---- */
.glass-input {
    background: var(--glass-bg-subtle);
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-sm);
    color: var(--color-text);
    padding: 10px 16px;
    font-size: 14px;
    font-family: var(--font-sans);
    transition: border-color var(--duration-fast) var(--ease-liquid),
                box-shadow var(--duration-fast) var(--ease-liquid);
}
.glass-input:focus {
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px var(--color-primary-glow);
    outline: none;
}

/* ---- 通用分段胶囊（复用 .model-pills 模式） ---- */
.glass-pill-group {
    display: inline-flex; gap: 0;
    border-radius: 999px;
    background: rgba(128,128,128,0.06);
    border: 1px solid var(--color-border);
    padding: 3px;
    position: relative;
    --pill-left: 3px;
    --pill-width: 60px;
}
.glass-pill-item {
    display: inline-flex; align-items: center; justify-content: center;
    padding: 7px 20px; border-radius: 999px; border: none;
    background: transparent; color: var(--color-text-muted);
    font-size: 13px; font-weight: 600; cursor: pointer;
    transition: color .35s ease;
    position: relative; z-index: 1;
    user-select: none;
}
.glass-pill-item:hover { color: var(--color-text); }
.glass-pill-item.active { color: #fff; transition: color .15s ease; }

.glass-pill-group::after {
    content: '';
    position: absolute;
    top: 3px; bottom: 3px;
    left: var(--pill-left, 3px);
    width: var(--pill-width, 60px);
    border-radius: 999px;
    background: rgba(14,165,233,0.25);
    border: 1px solid rgba(255,255,255,0.25);
    box-shadow:
        0 2px 12px rgba(14,165,233,0.25),
        inset 0 1px 0 rgba(255,255,255,0.2);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    transition:
        left .4s cubic-bezier(.34,1.56,.64,1),
        width .4s cubic-bezier(.34,1.56,.64,1),
        background .35s ease,
        box-shadow .35s ease;
    z-index: 0; pointer-events: none;
}

/* ---- 玻璃按钮体系 ---- */
.glass-btn {
    display: inline-flex; align-items: center; justify-content: center; gap: 6px;
    padding: 10px 22px;
    border-radius: 999px;
    border: 1px solid var(--glass-border);
    background: linear-gradient(135deg, rgba(255,255,255,.05) 0%, rgba(255,255,255,.01) 100%), var(--glass-bg-subtle);
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    color: var(--color-text);
    font-size: 14px; font-weight: 600;
    cursor: pointer;
    transition: all var(--duration-fast) var(--ease-liquid);
    position: relative; overflow: hidden;
}
.glass-btn:hover {
    border-color: var(--glass-border-high);
    background: linear-gradient(135deg, rgba(255,255,255,.08) 0%, rgba(255,255,255,.02) 100%), var(--glass-bg);
    transform: translateY(-1px);
    box-shadow: var(--glass-glow-primary);
}
.glass-btn:active { transform: translateY(0); }

.glass-btn-primary {
    background: linear-gradient(135deg, rgba(171,118,232,.35) 0%, rgba(124,58,237,.20) 100%), var(--glass-bg-strong);
    border-color: rgba(171,118,232,.35);
    box-shadow: 0 0 18px rgba(171,118,232,.15);
}
.glass-btn-primary:hover {
    background: linear-gradient(135deg, rgba(171,118,232,.45) 0%, rgba(124,58,237,.28) 100%), var(--glass-bg-float);
    border-color: rgba(171,118,232,.50);
    box-shadow: 0 0 28px rgba(171,118,232,.28);
}

.glass-btn-accent {
    background: linear-gradient(135deg, rgba(228,77,98,.30) 0%, rgba(160,17,58,.18) 100%), var(--glass-bg-strong);
    border-color: rgba(228,77,98,.30);
    box-shadow: 0 0 16px rgba(228,77,98,.12);
}
.glass-btn-accent:hover {
    background: linear-gradient(135deg, rgba(228,77,98,.40) 0%, rgba(160,17,58,.25) 100%), var(--glass-bg-float);
    border-color: rgba(228,77,98,.45);
    box-shadow: 0 0 26px rgba(228,77,98,.25);
}

.glass-btn-ghost {
    background: transparent;
    border-color: transparent;
    color: var(--color-text-muted);
}
.glass-btn-ghost:hover {
    background: rgba(255,255,255,.05);
    border-color: var(--glass-border);
    color: var(--color-text);
    box-shadow: none;
    transform: none;
}

.glass-btn-sm { padding: 6px 16px; font-size: 13px; }
.glass-btn-xs { padding: 4px 12px; font-size: 12px; }

/* ---- 按钮按压波纹 ---- */
.glass-btn-ripple { position: relative; overflow: hidden; }
.glass-btn-ripple::after {
    content: ''; position: absolute;
    inset: 0;
    background: radial-gradient(circle at center, rgba(255,255,255,.2) 0%, transparent 70%);
    opacity: 0; transform: scale(.5);
    transition: opacity var(--duration-fast), transform var(--duration-fast);
}
.glass-btn-ripple:active::after { opacity: 1; transform: scale(1.5); }

/* ---- 悬浮光晕呼吸 ---- */
@keyframes glass-breath-glow {
    0%, 100% { box-shadow: 0 0 8px rgba(171,118,232,.15); }
    50%      { box-shadow: 0 0 20px rgba(171,118,232,.30); }
}
.glass-breath {
    animation: glass-breath-glow 3s ease-in-out infinite;
}

/* ---- 液态流动渐变 ---- */
@keyframes glass-shift-gradient {
    0%   { background-position: 0% 50%; }
    50%  { background-position: 100% 50%; }
    100% { background-position: 0% 50%; }
}

/* ---- 光泽扫过 ---- */
@keyframes glass-shimmer {
    0%   { transform: translateX(-100%); }
    100% { transform: translateX(100%); }
}
.glass-shimmer {
    position: relative; overflow: hidden;
}
.glass-shimmer::after {
    content: '';
    position: absolute; top: 0; left: 0;
    width: 60%; height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,.06), transparent);
    transform: translateX(-100%);
    animation: glass-shimmer 2.5s ease-in-out infinite;
}

/* ---- 展开/收起 ---- */
.glass-collapse {
    overflow: hidden;
    transition: max-height var(--duration-normal) var(--ease-liquid),
                opacity var(--duration-fast) var(--ease-liquid);
}
.glass-collapse.collapsed { max-height: 0; opacity: 0; }

/* ---------- 13. 模态框 — 液态玻璃 ---------- */
.modal-overlay {
    display: none; position: fixed; inset: 0; z-index: 200;
    background: rgba(4,8,20,.62);
    backdrop-filter: blur(var(--glass-blur));
    -webkit-backdrop-filter: blur(var(--glass-blur));
    align-items: center; justify-content: center;
}
.modal-overlay.active { display: flex; }
.modal {
    width: 90%; max-width: 520px; max-height: 90vh; overflow-y: auto;
    padding: 28px; border-radius: 18px;
    background: linear-gradient(180deg, rgba(255,255,255,.08) 0%, rgba(255,255,255,.02) 100%), var(--glass-bg-strong);
    border: 1px solid var(--glass-border-high);
    backdrop-filter: blur(var(--glass-blur-heavy)) saturate(145%);
    -webkit-backdrop-filter: blur(var(--glass-blur-heavy)) saturate(145%);
    box-shadow: var(--glass-shadow), 0 0 60px rgba(171,118,232,.08);
    animation: glass-fade-scale var(--duration-normal) var(--ease-spring) both;
}
.modal-wide { max-width: 960px; }
.quiz-editor-modal { max-width: 1220px; padding: 26px 28px 28px; }
.modal h2 { font-size: 20px; font-weight: 700; color: #fff; margin-bottom: 20px; }
.modal-actions { display: flex; justify-content: flex-end; gap: 10px; margin-top: 20px; }
.inline-check {
    display: inline-flex; align-items: center; gap: 10px;
    font-size: 14px; color: var(--color-text);
}
.inline-check input { accent-color: var(--color-primary); width: 16px; height: 16px; }

/* ---------- 14.5. 测验 UI ---------- */
.quiz-toolbar-field { min-width: 280px; flex: 1; margin-bottom: 0; }
.quiz-editor-form {
    display: flex; flex-direction: column; gap: 20px;
}
.quiz-editor-meta {
    display: flex; flex-direction: column; gap: 16px;
    padding-bottom: 22px;
    border-bottom: 1px solid rgba(255,255,255,.06);
}
.quiz-ai-shell {
    display: flex; flex-direction: column; gap: 14px;
}
.quiz-ai-shell-toggle {
    display: flex; align-items: center; justify-content: space-between;
    gap: 18px; width: 100%; text-align: left;
    padding: 16px 18px; border-radius: 16px;
    border: 1px solid rgba(255,255,255,.08);
    background: linear-gradient(180deg, rgba(15,18,34,.94) 0%, rgba(20,23,43,.94) 100%);
    color: #fff;
    transition: border-color .2s, background .2s, transform .2s;
}
.quiz-ai-shell-toggle:hover {
    border-color: rgba(171, 118, 232,.28);
    background: linear-gradient(180deg, rgba(20,22,42,.98) 0%, rgba(24,28,52,.98) 100%);
}
.quiz-ai-shell-copy {
    display: flex; flex-direction: column; gap: 6px; min-width: 0;
}
.quiz-ai-shell-label {
    font-size: 12px; font-weight: 800; letter-spacing: .08em;
    text-transform: uppercase; color: #8ea0c6;
}
.quiz-ai-shell-copy strong {
    font-size: 15px; line-height: 1.5; color: #fff;
}
.quiz-ai-shell-meta {
    display: flex; align-items: center; justify-content: flex-end;
    gap: 12px; flex-wrap: wrap;
}
.quiz-ai-shell-action {
    display: inline-flex; align-items: center; gap: 8px;
    padding: 8px 12px; border-radius: 999px;
    border: 1px solid rgba(255,255,255,.09);
    background: rgba(255,255,255,.04);
    color: #f8fafc; font-size: 12px; font-weight: 700;
}
.quiz-ai-shell-action::before {
    content: '▾';
    font-size: 11px;
    transition: transform .2s ease;
}
.quiz-ai-shell.is-collapsed .quiz-ai-shell-action::before {
    transform: rotate(-90deg);
}
.quiz-ai-shell.is-collapsed .quiz-editor-workspace {
    display: none;
}
.quiz-editor-workspace {
    display: grid; grid-template-columns: minmax(300px, 360px) minmax(0, 1fr);
    border: 1px solid rgba(255,255,255,.08);
    border-radius: 18px;
    overflow: hidden;
    background: linear-gradient(180deg, rgba(9,11,22,.96) 0%, rgba(14,16,31,.96) 100%);
}
.quiz-editor-rail {
    display: flex; flex-direction: column;
    background: rgba(19,20,37,.96);
    border-right: 1px solid rgba(255,255,255,.07);
}
.quiz-editor-rail-head,
.quiz-editor-section,
.quiz-editor-note {
    padding: 18px 20px;
}
.quiz-editor-rail-head {
    display: flex; flex-direction: column; gap: 12px;
    border-bottom: 1px solid rgba(255,255,255,.07);
}
.quiz-editor-rail-head h3,
.quiz-editor-stage-head h3 {
    font-size: 16px; color: #fff;
}
.quiz-editor-section {
    border-bottom: 1px solid rgba(255,255,255,.06);
}
.quiz-editor-section-title {
    margin-bottom: 14px;
    font-size: 12px; font-weight: 700; letter-spacing: .08em;
    text-transform: uppercase; color: #8ea0c6;
}
.quiz-editor-note {
    font-size: 13px; line-height: 1.8; color: var(--color-text-muted);
    background: linear-gradient(180deg, rgba(255,255,255,.02) 0%, rgba(255,255,255,0) 100%);
}
.quiz-editor-stage {
    display: flex; flex-direction: column;
    min-width: 0;
    background: rgba(12,14,27,.98);
}
.quiz-editor-stage-head {
    display: flex; align-items: flex-start; justify-content: space-between;
    gap: 16px; flex-wrap: wrap;
    padding: 18px 22px 16px;
    border-bottom: 1px solid rgba(255,255,255,.06);
}
.quiz-editor-divider {
    border-top: 1px solid rgba(255,255,255,.06);
}
.quiz-builder-list, .review-answer-list {
    display: flex; flex-direction: column; gap: 16px;
}
.quiz-builder-empty {
    text-align: center; padding: 32px 20px; border-radius: var(--radius);
    border: 1px dashed rgba(171, 118, 232,.35);
    background: rgba(171, 118, 232,.05); color: var(--color-text-muted);
}
.quiz-builder-empty .icon { font-size: 42px; margin-bottom: 10px; }
.quiz-builder-empty h3 { color: #fff; margin-bottom: 6px; }
.quiz-card,
.quiz-question-card,
.answer-review-card,
.quiz-answer-card {
    padding: 20px 22px; border-radius: var(--radius);
    background: linear-gradient(180deg, rgba(22,19,42,.96) 0%, rgba(15,15,31,.96) 100%);
    border: 1px solid rgba(255,255,255,.06);
    box-shadow: inset 0 1px 0 rgba(255,255,255,.03);
}
.quiz-question-card {
    border-left: 4px solid rgba(171, 118, 232,.52);
}
.quiz-card-detail {
    margin-top: 16px; padding-top: 16px;
    border-top: 1px solid rgba(255,255,255,.06);
}
.quiz-question-grid {
    display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 16px;
}
.quiz-ai-lock {
    display: inline-flex; align-items: center; gap: 8px;
    width: fit-content;
    padding: 8px 12px; border-radius: 999px;
    border: 1px solid rgba(212, 162, 76,.25);
    background: rgba(36,66,122,.28); color: #dbeafe;
    font-size: 12px; font-weight: 700;
}
.quiz-ai-file-list {
    display: flex; flex-wrap: wrap; gap: 8px;
    margin-top: 10px;
}
.quiz-ai-file-list.is-empty {
    font-size: 13px; color: var(--color-text-muted);
}
.quiz-ai-file-picker {
    display: flex; align-items: center; gap: 12px; flex-wrap: wrap;
    padding: 10px 12px;
    border-radius: 12px;
    border: 1px dashed rgba(255,255,255,.1);
    background: rgba(8,12,24,.94);
}
.quiz-ai-file-trigger {
    min-width: 0;
}
.quiz-ai-file-hint {
    font-size: 12px; color: var(--color-text-muted);
}
.quiz-ai-file-input {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}
.quiz-ai-file-chip {
    display: inline-flex; align-items: center;
    padding: 6px 10px; border-radius: 999px;
    background: rgba(255,255,255,.04);
    border: 1px solid rgba(255,255,255,.08);
    color: #d7ddf6; font-size: 12px;
}
.quiz-ai-status {
    display: flex; align-items: flex-start; justify-content: space-between; gap: 12px;
    padding: 14px 22px 12px;
    border-bottom: 1px solid rgba(255,255,255,.06);
    color: var(--color-text-muted);
}
.quiz-ai-status[data-tone="info"] {
    color: #bfdbfe;
}
.quiz-ai-status[data-tone="success"] {
    color: #bbf7d0;
}
.quiz-ai-status[data-tone="error"] {
    color: #fecaca;
}
.quiz-ai-draft-summary {
    padding: 10px 22px 0;
    color: var(--color-text-muted);
    font-size: 13px;
    line-height: 1.7;
}
.quiz-ai-viewbar {
    display: flex; align-items: center; justify-content: space-between;
    gap: 12px; flex-wrap: wrap;
    padding: 14px 22px 0;
}
.quiz-ai-tabs {
    display: inline-flex; gap: 6px; flex-wrap: wrap;
}
.quiz-ai-tab {
    padding: 8px 12px; border-radius: 10px;
    border: 1px solid rgba(255,255,255,.07);
    background: transparent; color: var(--color-text-muted);
    font-size: 13px; font-weight: 700;
}
.quiz-ai-tab.active {
    color: #fff;
    background: rgba(171, 118, 232,.16);
    border-color: rgba(171, 118, 232,.36);
}
.quiz-ai-pane {
    display: none;
    padding: 16px 22px 22px;
    min-height: 320px;
}
.quiz-ai-pane.active {
    display: block;
}
.quiz-ai-pane-empty {
    display: flex; align-items: center; justify-content: center;
    min-height: 200px;
    border: 1px dashed rgba(255,255,255,.1);
    border-radius: 14px;
    color: var(--color-text-muted);
    text-align: center;
}
.quiz-ai-stream {
    min-height: 280px; max-height: 420px; overflow: auto;
    padding: 18px; border-radius: 14px;
    border: 1px solid rgba(255,255,255,.06);
    background: #0a1120; color: #e2e8f0;
    font-family: Consolas, "Courier New", monospace;
    font-size: 13px; line-height: 1.7;
    white-space: pre-wrap; word-break: break-word;
}
.quiz-ai-stat-grid {
    display: grid; grid-template-columns: repeat(auto-fit, minmax(140px, 1fr)); gap: 12px;
}
.quiz-ai-stat-card {
    padding: 14px; border-radius: 12px;
    border: 1px solid rgba(255,255,255,.06);
    background: #11192c;
}
.quiz-ai-stat-card strong {
    display: block; margin-top: 8px; font-size: 22px; color: #fff;
}
.quiz-ai-report {
    min-height: 280px;
    padding: 18px; border-radius: 14px;
    border: 1px solid rgba(255,255,255,.06);
    background: #0f1729;
    white-space: pre-wrap; word-break: break-word; line-height: 1.7;
}
.quiz-ai-report.is-empty {
    color: var(--color-text-muted);
}
.quiz-ai-actions {
    display: flex; gap: 10px; flex-wrap: wrap; justify-content: flex-end;
}
.quiz-agent-draft-card {
    padding: 22px;
    border-radius: 16px;
    border: 1px solid rgba(212, 162, 76,.24);
    background:
        radial-gradient(circle at top right, rgba(212, 162, 76,.12), transparent 30%),
        linear-gradient(180deg, rgba(9,14,28,.98) 0%, rgba(14,20,38,.98) 100%);
    box-shadow: inset 0 1px 0 rgba(255,255,255,.04), 0 20px 40px rgba(3,8,20,.28);
}
.quiz-agent-draft-head {
    display: flex; align-items: flex-start; justify-content: space-between;
    gap: 16px; margin-bottom: 14px;
}
.quiz-agent-draft-label {
    display: inline-flex; align-items: center;
    margin-bottom: 8px; padding: 6px 10px;
    border-radius: 999px;
    background: rgba(59,130,246,.14);
    border: 1px solid rgba(212, 162, 76,.28);
    color: #dbeafe; font-size: 12px; font-weight: 700;
    letter-spacing: .04em;
}
.quiz-agent-draft-head h3 {
    font-size: 16px; color: #fff;
}
.quiz-agent-draft-pulse {
    width: 12px; height: 12px; margin-top: 6px;
    border-radius: 999px;
    background: #60a5fa;
    box-shadow: 0 0 0 rgba(212, 162, 76,.5);
    animation: quiz-agent-pulse 1.2s infinite;
}
.quiz-agent-draft-preview {
    min-height: 220px; max-height: 360px; overflow: auto;
    margin-top: 14px; padding: 16px;
    border-radius: 14px;
    border: 1px solid rgba(255,255,255,.06);
    background: rgba(5,11,24,.96);
    color: #dbeafe;
    font-family: Consolas, "Courier New", monospace;
    font-size: 13px; line-height: 1.7;
    white-space: pre-wrap; word-break: break-word;
}
.quiz-agent-writing-field {
    border-color: rgba(212, 162, 76,.42) !important;
    box-shadow: 0 0 0 3px rgba(212, 162, 76,.14), 0 0 18px rgba(212, 162, 76,.12) !important;
    background: rgba(16,24,42,.94) !important;
}
.quiz-question-card-agent-enter {
    animation: quiz-agent-card-enter .45s cubic-bezier(.22, 1, .36, 1);
}
.quiz-question-card-agent-writing {
    border-left-color: rgba(212, 162, 76,.9);
    box-shadow: inset 0 1px 0 rgba(255,255,255,.03), 0 0 0 1px rgba(212, 162, 76,.18), 0 14px 32px rgba(15,23,42,.3);
}

@keyframes quiz-agent-pulse {
    0% {
        transform: scale(.92);
        box-shadow: 0 0 0 0 rgba(212, 162, 76,.48);
    }
    70% {
        transform: scale(1);
        box-shadow: 0 0 0 14px rgba(212, 162, 76,0);
    }
    100% {
        transform: scale(.92);
        box-shadow: 0 0 0 0 rgba(212, 162, 76,0);
    }
}

@keyframes quiz-agent-card-enter {
    0% {
        opacity: 0;
        transform: translateY(18px) scale(.98);
    }
    100% {
        opacity: 1;
        transform: translateY(0) scale(1);
    }
}

.question-options, .quiz-option-group {
    display: flex; flex-direction: column; gap: 12px;
}
.quiz-option-row {
    display: grid; grid-template-columns: auto 1fr auto;
    gap: 12px; align-items: center;
}
.quiz-option-pill {
    display: inline-flex; align-items: center; gap: 8px;
    padding: 9px 12px; border-radius: 10px;
    background: rgba(255,255,255,.05); border: 1px solid var(--color-border);
    color: #fff; min-width: 72px;
}
.quiz-option-pill input,
.quiz-option-selectable input { accent-color: var(--color-primary); }
.quiz-option-selectable {
    display: flex; align-items: flex-start; gap: 12px;
    padding: 14px 16px; border-radius: 12px;
    border: 1px solid var(--color-border);
    background: rgba(255,255,255,.03);
    transition: border-color .2s, background .2s;
}
.quiz-option-selectable:hover {
    border-color: rgba(171, 118, 232,.25);
    background: rgba(255,255,255,.05);
}
.quiz-option-selectable span { line-height: 1.6; }
.quiz-answer-stack {
    display: grid; gap: 12px;
}
.quiz-answer-stack label,
.quiz-answer-meta-item span:first-child {
    display: block; margin-bottom: 6px;
    font-size: 12px; font-weight: 700; color: var(--color-text-muted);
}
.quiz-answer-box {
    padding: 14px 16px; border-radius: 12px;
    border: 1px solid var(--color-border);
    background: rgba(255,255,255,.04);
    white-space: pre-wrap; word-break: break-word;
}
.quiz-reference-box {
    border-color: rgba(171, 118, 232,.28);
    background: rgba(171, 118, 232,.08);
}
.quiz-answer-meta {
    display: grid; grid-template-columns: repeat(auto-fit, minmax(180px, 1fr)); gap: 12px;
}
.quiz-answer-meta-item {
    padding: 14px 16px; border-radius: 12px;
    border: 1px solid var(--color-border);
    background: rgba(255,255,255,.04);
}
.quiz-answer-meta-item strong { color: #fff; }
.quiz-short-answer { min-height: 120px; }

@media (max-width: 768px) {
    .quiz-editor-modal { width: 96%; padding: 22px 18px 20px; }
    .quiz-ai-shell-toggle,
    .quiz-ai-shell-meta {
        align-items: flex-start; flex-direction: column;
    }
    .quiz-editor-workspace {
        grid-template-columns: 1fr;
    }
    .quiz-editor-rail {
        border-right: none;
        border-bottom: 1px solid rgba(255,255,255,.07);
    }
    .quiz-ai-status {
        align-items: flex-start; flex-direction: column;
    }
    .quiz-ai-viewbar,
    .quiz-editor-stage-head {
        align-items: flex-start; flex-direction: column;
    }
    .quiz-ai-actions {
        justify-content: flex-start;
    }
    .study-catalog-head,
    .study-catalog-row,
    .study-catalog-section-head,
    .study-catalog-node {
        grid-template-columns: 1fr;
    }
    .study-catalog-node,
    .study-catalog-row,
    .study-catalog-section-head {
        padding-right: 14px;
    }
    .study-catalog-row,
    .study-catalog-section-head {
        padding-left: 18px;
    }
    .study-catalog-row--section,
    .study-catalog-empty-row {
        padding-left: 30px;
    }
    .study-catalog-head span:last-child,
    .study-catalog-status,
    .study-catalog-node-meta {
        justify-self: flex-start;
        text-align: left;
    }
}

/* ---------- 14. 登录/注册 ---------- */
.auth-container {
    min-height: calc(100vh - var(--nav-height));
    display: flex; align-items: center; justify-content: center; padding: 40px 20px;
}
.auth-box {
    width: 100%; max-width: 420px; padding: 36px;
    border-radius: 22px;
    background: linear-gradient(180deg, rgba(255,255,255,.1) 0%, rgba(255,255,255,.02) 100%), var(--glass-bg-strong);
    backdrop-filter: blur(var(--glass-blur-heavy)) saturate(145%);
    -webkit-backdrop-filter: blur(var(--glass-blur-heavy)) saturate(145%);
    border: 1px solid var(--glass-border-high);
    box-shadow: var(--glass-shadow), 0 0 60px rgba(171,118,232,.06);
    animation: glass-fade-scale var(--duration-slow) var(--ease-spring) both;
}
.auth-box h1 { font-size: 24px; font-weight: 800; text-align: center; margin-bottom: 6px; }
.auth-box .subtitle { text-align: center; color: var(--color-text-muted); font-size: 14px; margin-bottom: 28px; }
.auth-tabs {
    display: flex; gap: 4px; margin-bottom: 24px;
    background: rgba(128,128,128,.06); border-radius: 999px; padding: 4px;
    border: 1px solid var(--glass-border);
}
.auth-tabs button {
    flex: 1; padding: 8px; border: none; border-radius: 999px;
    font-size: 14px; font-weight: 600; background: transparent;
    color: var(--color-text-muted);
    transition: all var(--duration-normal) var(--ease-liquid);
}
.auth-tabs button.active { background: var(--color-primary); color: #fff; box-shadow: 0 2px 12px var(--color-primary-glow); }
.auth-tabs button:hover:not(.active) { color: var(--color-text); }
.auth-divider { text-align: center; color: var(--color-text-muted); font-size: 13px; margin: 16px 0; }
.auth-link { color: var(--color-primary); cursor: pointer; }
.auth-link:hover { text-decoration: underline; }

/* ---------- 15. 提示消息 ---------- */
.toast-container { position: fixed; top: 80px; right: 20px; z-index: 300; display: flex; flex-direction: column; gap: 8px; }
.toast {
    padding: 12px 20px; border-radius: 10px; font-size: 14px;
    color: #fff; min-width: 260px; animation: slideIn .3s var(--transition);
    box-shadow: 0 8px 24px rgba(0,0,0,.3);
}
.toast-success { background: linear-gradient(135deg, #16a34a, #22c55e); }
.toast-error { background: linear-gradient(135deg, #b91c1c, #e0444c); }
.toast-info { background: linear-gradient(135deg, #7c3aed, #a855f7); }
@keyframes slideIn { from { transform: translateX(100%); opacity: 0; } to { transform: translateX(0); opacity: 1; } }

/* ---------- 16. 空状态 ---------- */
.empty-state {
    text-align: center; padding: 60px 20px; color: var(--color-text-muted);
}
.empty-state .icon { font-size: 48px; margin-bottom: 12px; }
.empty-state h3 { font-size: 18px; color: #fff; margin-bottom: 8px; }
.empty-state p { font-size: 14px; margin-bottom: 20px; }

/* ---------- 17. 两栏布局 ---------- */
.layout-split { display: grid; grid-template-columns: 1fr 340px; gap: 24px; }
.course-detail-layout { grid-template-columns: minmax(0, 1fr) 400px; }
.course-detail-sidebar { min-width: 0; }

/* ---------- 18. Tabs — 液态玻璃增强 ---------- */
.tabs {
    display: flex; gap: 4px; margin-bottom: 24px;
    border-bottom: 1px solid var(--glass-border);
    padding: 4px 4px 0 4px;
    background: var(--glass-bg-subtle);
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    border-radius: var(--radius) var(--radius) 0 0;
    overflow-x: auto;
}
.tabs button {
    padding: 10px 18px; border: none; background: transparent;
    color: var(--color-text-muted); font-size: 14px; font-weight: 600;
    border-bottom: 2px solid transparent;
    transition: color var(--duration-normal) var(--ease-liquid),
                border-color var(--duration-normal) var(--ease-liquid);
    margin-bottom: -1px; white-space: nowrap;
    position: relative;
}
.tabs button.active {
    color: var(--color-primary);
    border-bottom-color: var(--color-primary);
    text-shadow: 0 0 12px var(--color-primary-glow);
}
.tabs button:hover { color: #fff; }
.tab-panel { display: none; }
.tab-panel.active { display: block; }
.lab-panel { display: none; }
.lab-panel.active { display: block; }
.assign-panel { display: none; }
.assign-panel.active { display: block; }

@supports not ((backdrop-filter: blur(1px)) or (-webkit-backdrop-filter: blur(1px))) {
    .site-nav,
    .card,
    .course-card,
    .study-catalog,
    .modal,
    .auth-box {
        background: rgba(10, 15, 28, 0.94);
    }
}

@media (prefers-reduced-motion: reduce) {
    html { scroll-behavior: auto; }
    body {
        animation: none !important;
        opacity: 1 !important;
        transform: none !important;
        transition: none !important;
    }
}

/* ---------- 19. 批改图片对比 ---------- */
.lab-grade-images {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 14px;
    margin-bottom: 16px;
}
.lab-grade-image-pane {
    background: rgba(255,255,255,.03);
    border: 1px solid var(--color-border);
    border-radius: 10px;
    padding: 10px;
    text-align: center;
}
.lab-grade-image-pane img {
    max-width: 100%;
    max-height: 320px;
    border-radius: 6px;
    object-fit: contain;
    display: block;
    margin: 0 auto;
}
.lab-grade-label {
    font-size: 12px;
    font-weight: 600;
    color: var(--color-text-muted);
    margin-bottom: 8px;
    text-align: center;
}
@media (max-width: 600px) {
    .lab-grade-images { grid-template-columns: 1fr; }
}

/* ---------- 20. 加载动画 ---------- */
.spinner {
    width: 32px; height: 32px; border: 3px solid var(--color-border);
    border-top-color: var(--color-primary); border-radius: 50%;
    animation: spin .8s linear infinite; margin: 40px auto;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* ---------- 20. 分数显示 ---------- */
.score-display { font-size: 32px; font-weight: 800; }
.score-high { color: var(--color-success); }
.score-mid { color: var(--color-warning); }
.score-low { color: var(--color-accent); }

/* ---------- 21. 页脚 — 液态玻璃 ---------- */
.site-footer {
    text-align: center; padding: 28px 24px; font-size: 13px;
    color: var(--color-text-muted);
    border-top: 1px solid var(--glass-border);
    margin-top: auto;
    background: linear-gradient(180deg, transparent 0%, var(--glass-bg-subtle) 30%, var(--glass-bg) 100%);
    backdrop-filter: blur(var(--glass-blur));
    -webkit-backdrop-filter: blur(var(--glass-blur));
    position: relative;
}
/* 页脚顶部微光分割线 */
.site-footer::before {
    content: '';
    position: absolute;
    top: 0; left: 50%; transform: translateX(-50%);
    width: 60%; max-width: 600px; height: 1px;
    background: linear-gradient(90deg, transparent, rgba(171,118,232,.25), rgba(212,162,76,.15), transparent);
}
.site-footer a { color: var(--color-primary); text-decoration: none; }
.site-footer a:hover { text-decoration: underline; }
.site-footer .footer-links { margin-bottom: 8px; }
.site-footer .footer-links .sep { margin: 0 10px; opacity: .4; }
.site-footer .visit-stats { color: rgba(171, 118, 232,.6); margin-bottom: 4px; }
.site-footer .footer-disclaimer { margin-top: 6px; color: rgba(255,255,255,.3); font-size: 12px; }

/* ═══════════════════════════════════════════════
   23. AI Thinking 动画系统 (Phase 3)
   ═══════════════════════════════════════════════ */

/* --- 23a. 流光 Shimmer 动画 --- */
@keyframes ai-shimmer {
    0%   { background-position: -200% 0; }
    100% { background-position: 200% 0; }
}

.ai-shimmer-text {
    background: linear-gradient(
        90deg,
        var(--color-text-muted) 0%,
        var(--color-primary) 35%,
        var(--color-secondary) 65%,
        var(--color-text-muted) 100%
    );
    background-size: 200% 100%;
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    animation: ai-shimmer 3s ease-in-out infinite;
}

/* thinking 状态加速 */
.ai-shimmer-text.is-active {
    animation-duration: 1.5s;
}

/* --- 23b. 脉冲指示器 --- */
@keyframes ai-pulse {
    0%, 100% { opacity: 0.3; transform: scale(0.85); }
    50%      { opacity: 1;   transform: scale(1.15); }
}

.ai-pulse-dot {
    display: inline-block;
    width: 9px; height: 9px;
    border-radius: 50%;
    background: var(--color-primary);
    box-shadow: 0 0 10px var(--color-primary-glow);
    animation: ai-pulse 1.4s ease-in-out infinite;
    flex-shrink: 0;
}

.ai-pulse-dot[data-tone="idle"]       { background: var(--color-text-muted); box-shadow: none; animation-play-state: paused; opacity: 0.5; }
.ai-pulse-dot[data-tone="connecting"] { background: var(--color-primary); }
.ai-pulse-dot[data-tone="thinking"]   { background: var(--color-primary); animation-duration: 0.9s; }
.ai-pulse-dot[data-tone="streaming"]  { background: var(--color-secondary); }
.ai-pulse-dot[data-tone="done"]       { background: var(--color-success); animation-play-state: paused; opacity: 1; }
.ai-pulse-dot[data-tone="error"]      { background: var(--color-accent); animation-play-state: paused; opacity: 1; }

/* --- 23c. AI 快速操作栏 --- */
.ai-quick-bar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    flex-wrap: wrap;
    padding: 10px 0;
    margin-bottom: 4px;
}

.ai-quick-bar-left {
    display: flex;
    align-items: center;
    gap: 12px;
    flex-wrap: wrap;
}

.ai-model-badge {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 6px 14px;
    border-radius: 999px;
    font-size: 13px;
    font-weight: 600;
    color: var(--color-text-muted);
    background: rgba(255,255,255,.04);
    border: 1px solid rgba(255,255,255,.08);
    transition: all 0.3s;
}

/* --- 23d. 按钮发光效果 --- */
@keyframes btn-glow-pulse {
    0%, 100% { box-shadow: 0 0 12px var(--color-primary-glow); }
    50%      { box-shadow: 0 0 24px rgba(171,118,232,0.45), 0 0 48px rgba(171,118,232,0.15); }
}

.btn-glow {
    animation: btn-glow-pulse 2.5s ease-in-out infinite;
}

.btn-glow:hover {
    animation: none;
    box-shadow: 0 0 32px rgba(171,118,232,0.55), 0 0 64px rgba(171,118,232,0.2) !important;
}

/* --- 23e. AI 状态过渡 (Vue <Transition>) --- */
.ai-status-enter-active { transition: all 0.35s cubic-bezier(0.22, 1, 0.36, 1); }
.ai-status-leave-active { transition: all 0.2s ease-in; }
.ai-status-enter-from { opacity: 0; transform: translateY(-10px); }
.ai-status-leave-to   { opacity: 0; transform: translateY(8px); }

/* --- 23f. 状态栏增强 --- */
.ai-status-bar {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 10px 0;
    min-height: 36px;
}

.ai-status-label {
    font-size: 13px;
    font-weight: 500;
    transition: color 0.3s;
}

/* --- 23g. 卡片列表动画 (Vue <TransitionGroup>) --- */
.card-list-enter-active { transition: all 0.4s cubic-bezier(0.22, 1, 0.36, 1); }
.card-list-leave-active { transition: all 0.25s ease-in; position: absolute; }
.card-list-enter-from { opacity: 0; transform: translateY(20px) scale(0.97); }
.card-list-leave-to   { opacity: 0; transform: translateX(-30px); }
.card-list-move { transition: transform 0.3s ease; }

/* --- 23h. Toggle 开关 --- */
.toggle-switch { position: relative; display: inline-flex; align-items: center; gap: 10px; cursor: pointer; user-select: none; }
.toggle-switch input { display: none; }
.toggle-switch .toggle-track {
    width: 44px; height: 24px;
    border-radius: 999px;
    background: rgba(255,255,255,.1);
    border: 1px solid var(--color-border);
    transition: background .3s, border-color .3s;
    position: relative; flex-shrink: 0;
}
.toggle-switch .toggle-track::after {
    content: ''; position: absolute; top: 2px; left: 2px;
    width: 18px; height: 18px; border-radius: 50%;
    background: var(--color-text-muted);
    transition: transform .3s, background .3s;
}
.toggle-switch input:checked + .toggle-track {
    background: rgba(171,118,232,.25); border-color: rgba(171,118,232,.4);
}
.toggle-switch input:checked + .toggle-track::after {
    transform: translateX(20px); background: var(--color-primary);
    box-shadow: 0 0 8px var(--color-primary-glow);
}
.toggle-switch .toggle-label { font-size: 14px; color: var(--color-text); }

/* --- 23i. AI 芯片式多选参考 --- */
.ai-ref-header {
    display: flex; align-items: center; justify-content: space-between;
    gap: 8px; margin-bottom: 6px;
}
.ai-ref-label { font-size: 13px; color: var(--color-text-muted); font-weight: 600; }
.ai-ref-count { font-size: 12px; color: var(--color-primary); }

.ai-ref-chips {
    display: flex; flex-wrap: wrap; gap: 6px;
    margin-bottom: 6px; min-height: 0;
}
.ai-ref-chip {
    display: inline-flex; align-items: center; gap: 4px;
    padding: 4px 10px;
    border-radius: 999px;
    font-size: 12px; line-height: 1.5;
    background: rgba(171,118,232,.15);
    border: 1px solid rgba(171,118,232,.3);
    color: #d7c9f0;
    animation: chip-in .25s cubic-bezier(.22,1,.36,1);
}
@keyframes chip-in { from { opacity:0; transform:scale(.85); } to { opacity:1; transform:none; } }
.ai-ref-chip-remove {
    background: none; border: none;
    color: var(--color-text-muted); font-size: 15px;
    cursor: pointer; padding: 0 2px; line-height: 1;
    transition: color .15s;
}
.ai-ref-chip-remove:hover { color: var(--color-accent); }

.ai-ref-dropdown {
    position: relative;
}
.ai-ref-dropdown-toggle {
    width: 100%; text-align: left;
    padding: 8px 12px;
    border-radius: 10px;
    font-size: 13px;
    background: rgba(255,255,255,.03);
    border: 1px solid var(--color-border);
    color: var(--color-text-muted);
    cursor: pointer;
    transition: border-color .2s, background .2s;
}
.ai-ref-dropdown-toggle:hover { border-color: rgba(171,118,232,.3); background: rgba(255,255,255,.05); }
.ai-ref-dropdown.open .ai-ref-dropdown-toggle { border-radius: 10px 10px 0 0; border-color: rgba(171,118,232,.4); }

.ai-ref-dropdown-body {
    border: 1px solid rgba(171,118,232,.2);
    border-top: none;
    border-radius: 0 0 10px 10px;
    background: rgba(18,14,35,.95);
    backdrop-filter: blur(8px);
    max-height: 200px; overflow-y: auto;
}
.ai-ref-option {
    display: flex; align-items: center; gap: 8px;
    padding: 7px 12px;
    font-size: 13px; color: var(--color-text-muted);
    cursor: pointer; transition: background .15s;
}
.ai-ref-option:hover { background: rgba(255,255,255,.04); }
.ai-ref-option.checked { color: var(--color-primary); background: rgba(171,118,232,.08); }
.ai-ref-option input[type="checkbox"] { accent-color: var(--color-primary); width: 14px; height: 14px; flex-shrink: 0; }

/* --- 23j. 按钮 loading 态 --- */
.btn-loading {
    opacity: 0.7;
    cursor: wait !important;
    pointer-events: none;
    position: relative;
}
.btn-loading::after {
    content: '';
    position: absolute; inset: 0;
    background: rgba(255,255,255,.06);
    border-radius: inherit;
    animation: ai-pulse 1s ease-in-out infinite;
}

/* ---------- 22. 工具类 ---------- */
.flex { display: flex; }
.flex-col { flex-direction: column; }
.items-center { align-items: center; }
.items-end { align-items: flex-end; }
.justify-between { justify-content: space-between; }
.gap-8 { gap: 8px; }
.gap-12 { gap: 12px; }
.gap-16 { gap: 16px; }
.gap-20 { gap: 20px; }
.mb-12 { margin-bottom: 12px; }
.mb-16 { margin-bottom: 16px; }
.mb-20 { margin-bottom: 20px; }
.mb-24 { margin-bottom: 24px; }
.mt-12 { margin-top: 12px; }
.mt-24 { margin-top: 24px; }
.text-muted { color: var(--color-text-muted); }
.text-sm { font-size: 13px; }
.text-center { text-align: center; }
.text-right { text-align: right; }
.hidden { display: none !important; }
.w-full { width: 100%; }
.wrap-mobile { flex-wrap: wrap; }

/* ---------- 23. 响应式 ---------- */
@media (max-width: 1024px) {
    .layout-split { grid-template-columns: 1fr; }
    .course-detail-layout { grid-template-columns: 1fr; }
    .modal-wide { width: 94%; }
}
@media (max-width: 768px) {
    .nav-links { display: none; position: fixed; top: var(--nav-height); left: 0; right: 0; flex-direction: column; background: rgba(10,10,26,.95); backdrop-filter: blur(20px); padding: 16px; gap: 4px; border-bottom: 1px solid var(--color-border); }
    .nav-links.open { display: flex; }
    .nav-hamburger { display: flex; }
    .page-container { padding: 20px 16px 40px; }
    .course-grid { grid-template-columns: 1fr; }
    .stats-grid { grid-template-columns: repeat(2, 1fr); }
    .page-header h1 { font-size: 22px; }
    .quiz-option-row { grid-template-columns: 1fr; }
    .quiz-answer-meta, .quiz-question-grid { grid-template-columns: 1fr; }
    .quiz-toolbar-field { min-width: 100%; }
}
@media (max-width: 480px) {
    .stats-grid { grid-template-columns: 1fr; }
    .auth-box { padding: 24px 18px; }
}

/* === Merged from main site CSS (server-debug-fix #9) === */
@keyframes fadeInCharCentered { from{opacity:0;transform:translate(-50%,30px)} to{opacity:1;transform:translate(-50%,0)} }

/* ---------- 16. 鍝嶅簲寮?---------- */
@media(max-width:1024px){
    .footer-grid{grid-template-columns:1fr 1fr}
    .nav-links a{padding:6px 10px;font-size:13px}
    .nav-search input{width:120px}
}

@keyframes fadeInText { from{opacity:0;transform:scale(.9)} to{opacity:1;transform:scale(1)} }
@keyframes fadeInCharCentered { from{opacity:0;transform:translate(-50%,30px)} to{opacity:1;transform:translate(-50%,0)} }

/* ---------- 16. 鍝嶅簲寮?---------- */
@media(max-width:1024px){
    .footer-grid{grid-template-columns:1fr 1fr}
    .nav-links a{padding:6px 10px;font-size:13px}
    .nav-search input{width:120px}
}

@keyframes fadeInUp { from{opacity:0;transform:translateY(20px)} to{opacity:1;transform:translateY(0)} }
@keyframes fadeInText { from{opacity:0;transform:scale(.9)} to{opacity:1;transform:scale(1)} }
@keyframes fadeInCharCentered { from{opacity:0;transform:translate(-50%,30px)} to{opacity:1;transform:translate(-50%,0)} }

/* ---------- 16. 鍝嶅簲寮?---------- */
@media(max-width:1024px){
    .footer-grid{grid-template-columns:1fr 1fr}
    .nav-links a{padding:6px 10px;font-size:13px}
    .nav-search input{width:120px}
}