/* ===== CSS Reset & Variables ===== */
:root {
    /* Gold & Navy — 尊贵学院风 */
    --primary: #c9a84c;
    --primary-dark: #b8942f;
    --primary-light: #2a2540;
    --primary-mid: #3d3558;
    --accent: #c9a84c;
    --accent-dark: #b8942f;
    --bg: #0c1425;
    --bg-card: #141d35;
    --bg-elevated: #1e2a4a;
    --text: #f0ead2;
    --text-muted: #a0997a;
    --text-light: #6b6352;
    --border: #2a3556;
    --border-bright: #3d4a6b;
    --shadow: 0 2px 8px rgba(0,0,0,0.5), 0 1px 3px rgba(0,0,0,0.3);
    --shadow-lg: 0 10px 30px rgba(0,0,0,0.6), 0 4px 12px rgba(0,0,0,0.4);
    --radius: 12px;
    --radius-sm: 8px;
    --sidebar-w: 320px;
    --header-h: 64px;
    --transition: 0.3s ease;
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html { font-size: 16px; scroll-behavior: smooth; }

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.6;
    min-height: 100vh;
    overflow-x: hidden;
}

a { color: var(--primary); text-decoration: none; }
a:hover { text-decoration: underline; }

/* ===== Header ===== */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: var(--header-h);
    background: linear-gradient(180deg, #111827 0%, #0c1425 100%);
    border-bottom: 1px solid var(--border);
    border-bottom-color: var(--primary-dark);
    display: flex;
    align-items: center;
    padding: 0 20px;
    z-index: 100;
    box-shadow: 0 2px 12px rgba(0,0,0,0.5), 0 1px 0 rgba(201,168,76,0.15);
}

.header-brand {
    display: flex;
    align-items: center;
    gap: 12px;
    flex: 1;
    min-width: 0;
}

.header-logo {
    height: 44px;
    width: auto;
    max-width: 380px;
    object-fit: contain;
    flex-shrink: 0;
    display: block;
}

.header-title {
    font-size: 1.0625rem;
    font-weight: 700;
    color: var(--text);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    letter-spacing: 0.01em;
}

.header-title-suffix {
    font-size: 0.6875rem;
    color: var(--primary);
    white-space: nowrap;
    font-weight: 600;
    letter-spacing: 0.12em;
    text-transform: uppercase;
}

.header-right {
    display: flex;
    align-items: center;
    gap: 12px;
}

.menu-toggle {
    display: none;
    background: none;
    border: none;
    width: 40px;
    height: 40px;
    border-radius: var(--radius-sm);
    cursor: pointer;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 5px;
    transition: background var(--transition);
}

.menu-toggle:hover { background: var(--bg-elevated); }
.menu-toggle:hover span { background: var(--primary); }

.menu-toggle span {
    display: block;
    width: 22px;
    height: 2.5px;
    background: #c9a84c;
    border-radius: 2px;
    transition: var(--transition);
}

.menu-toggle.active span:nth-child(1) { transform: translateY(7.5px) rotate(45deg); }
.menu-toggle.active span:nth-child(2) { opacity: 0; }
.menu-toggle.active span:nth-child(3) { transform: translateY(-7.5px) rotate(-45deg); }

/* ===== Layout ===== */
.layout { display: flex; padding-top: var(--header-h); min-height: 100vh; }

/* ===== Sidebar ===== */
.sidebar {
    width: var(--sidebar-w);
    flex-shrink: 0;
    background: linear-gradient(180deg, #111827 0%, #0c1425 100%);
    border-right: 1px solid var(--border);
    height: calc(100vh - var(--header-h));
    position: sticky;
    top: var(--header-h);
    overflow-y: auto;
    transition: transform var(--transition);
    z-index: 50;
}

.sidebar::-webkit-scrollbar { width: 4px; }
.sidebar::-webkit-scrollbar-thumb { background: var(--border-bright); border-radius: 2px; }

.sidebar-content { padding: 0; }

.side-card .video-item { padding: 16px 14px; }
.side-card .video-item + .video-item { border-top: 1px solid var(--border); }

/* Video List in Sidebar */
.video-list { list-style: none; padding: 0; margin: 0; }

.video-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 12px 20px;
    cursor: pointer;
    transition: background var(--transition), border-color var(--transition);
    border-left: 3px solid transparent;
}

.video-item:hover { background: var(--primary-light); }
.video-item.active {
    background: var(--primary-light);
    border-left-color: var(--primary);
}

.video-item-index {
    width: 28px;
    height: 28px;
    border-radius: 50%;
    background: var(--bg-elevated);
    color: var(--text-muted);
    border: 1px solid var(--border);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.75rem;
    font-weight: 700;
    flex-shrink: 0;
    transition: var(--transition);
}

.video-item.active .video-item-index {
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    color: #0c1425;
    border-color: transparent;
    box-shadow: 0 0 12px rgba(201,168,76,0.3);
}

.video-item-info { flex: 1; min-width: 0; }
.video-item-title {
    font-size: 0.8125rem;
    font-weight: 600;
    color: var(--text);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.video-item .play-icon {
    width: 20px;
    height: 20px;
    flex-shrink: 0;
    color: var(--text-light);
}

.video-item.active .play-icon { color: var(--primary); }

/* ===== Main Content ===== */
.main {
    flex: 1;
    min-width: 0;
    padding: 24px;
    display: flex;
    flex-direction: column;
}

/* ===== Player Section ===== */
.player-section { flex: 1; display: flex; flex-direction: column; justify-content: center; }

#player-container {
    background: #000;
    border-radius: var(--radius);
    overflow: hidden;
    width: 100%;
    /* Placeholder only: fixed aspect ratio */
    aspect-ratio: 16 / 9;
    max-height: 70vh;
    position: relative;
    display: flex;
    flex-direction: column;
    box-shadow: var(--shadow-lg), 0 0 0 1px rgba(201,168,76,0.1);
}

#player-container.has-video .player-placeholder {
    display: none;
}

/* Video active: 高度优先的 16:9，画面完整、水平居中，两侧深色留白 */
#player-container.has-video {
    max-height: unset;
    flex: none;
    aspect-ratio: 16 / 9;
    width: min(100%, calc((100vh - 210px) * 16 / 9));
    margin: 0 auto;
    background: #000;
}

/* 播放时：整体垂直居中，四周留出少量边距 */
.main.playing { padding: 12px; }
.main.playing .video-info-panel { margin: 10px 16px 14px; }

/* Player iframe fills the container */
.player-frame {
    display: none;
    width: 100%;
    border: none;
    flex: 1;
    border-radius: var(--radius);
    overflow: hidden;
}

#player-container.has-video .player-frame {
    display: block;
}

.player-placeholder {
    position: absolute;
    inset: 0;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    color: #fff;
    background: linear-gradient(135deg, #0c1425 0%, #1e2a4a 50%, #0c1425 100%);
    gap: 16px;
}

.player-placeholder-icon {
    width: 72px;
    height: 72px;
    border: 2px solid rgba(201,168,76,0.4);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 32px;
    color: var(--primary);
    box-shadow: 0 0 30px rgba(201,168,76,0.15), inset 0 0 20px rgba(201,168,76,0.05);
}

.player-placeholder-text {
    font-size: 1.125rem;
    font-weight: 600;
    opacity: 0.9;
    color: #f0ead2;
    letter-spacing: 0.05em;
}

.player-placeholder-hint {
    font-size: 0.8125rem;
    opacity: 0.5;
}

.hint-mobile { display: none; }

.placeholder-info {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 6px;
    margin-top: 20px;
    padding-top: 16px;
    border-top: 1px solid rgba(201,168,76,0.15);
}

.placeholder-info span {
    font-size: 0.9375rem;
    opacity: 0.7;
    color: #f0ead2;
}

.placeholder-info span strong {
    color: var(--primary);
    font-weight: 700;
}

.placeholder-info span:last-child {
    font-size: 1rem;
    opacity: 0.9;
    color: var(--primary);
}

/* ===== Video Info Panel ===== */
.video-info-panel {
    margin-top: 20px;
    display: none;
}

.video-info-panel.visible { display: block; }

.video-info-title {
    font-size: 1.25rem;
    font-weight: 700;
    margin-bottom: 4px;
}

.video-info-meta {
    font-size: 0.8125rem;
    color: var(--text-muted);
    display: flex;
    gap: 16px;
    flex-wrap: wrap;
}

.video-info-badge {
    display: inline-flex;
    align-items: center;
    gap: 4px;
    padding: 2px 10px;
    border-radius: 20px;
    font-size: 0.75rem;
    font-weight: 600;
}

.badge-english { background: var(--primary-light); color: var(--primary); }
.badge-politics { background: #2a1f0a; color: #fcd34d; border: 1px solid #4a3810; }



/* ===== Mobile Overlay ===== */
.sidebar-overlay {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,0.6);
    z-index: 49;
}

.sidebar-overlay.visible { display: block; }

/* ===== Responsive ===== */
@media (max-width: 768px) {
    .header { padding: 0 12px; }
    .header-logo { height: 30px; max-width: 190px; }
    .header-title { font-size: 0.8125rem; }

    .menu-toggle { display: flex; }

    .sidebar {
        position: fixed;
        top: var(--header-h);
        bottom: 0;
        left: 0;
        /* dvh 跟随浏览器工具栏动态视口，避免列表底部被遮挡；旧浏览器回退 100vh（继承桌面规则） */
        height: calc(100vh - var(--header-h));
        height: calc(100dvh - var(--header-h));
        transform: translateX(-100%);
        width: min(88vw, 320px);
        z-index: 50;
        box-shadow: var(--shadow-lg);
        -webkit-overflow-scrolling: touch;
        overscroll-behavior: contain;
    }

    .sidebar.open { transform: translateX(0); }

    /* 侧栏打开时锁定背景滚动 */
    body.sidebar-open { overflow: hidden; }

    .main { padding: 12px; }

    .hint-desktop { display: none; }
    .hint-mobile { display: inline; }

    /* === 未播放：占位面板占屏幕大部分，避免内容被裁切 === */
    #player-container {
        border-radius: var(--radius-sm);
        aspect-ratio: auto;
        height: min(72vh, 460px);
        height: min(72dvh, 460px);
        max-height: none;
    }

    /* === 播放中：固定 16:9 铺满宽度，超高时以视口封顶（视频内部 contain 不变形） === */
    #player-container.has-video {
        flex: none;
        height: auto;
        width: 100%;
        aspect-ratio: 16 / 9;
        max-height: calc(100vh - 150px);
        max-height: calc(100dvh - 150px);
        margin: 0 auto;
        border-radius: var(--radius-sm);
    }

    /* 播放时缩小 main padding，给视频更多空间但保留少量边距 */
    .main.playing { padding: 8px; }
    .main.playing .video-info-panel { margin: 10px 4px 12px; }

    .player-frame {
        display: none;
        width: 100%;
        border: none;
        flex: 1;
        border-radius: var(--radius-sm);
        overflow: hidden;
    }

    .video-info-panel {
        margin-top: 10px;
    }

    .video-info-title { font-size: 0.9375rem; word-break: break-word; }

    .video-info-meta { font-size: 0.75rem; gap: 8px; }

    /* 占位区紧凑化，防止小屏裁切 */
    .player-placeholder { gap: 10px; padding: 0 16px; text-align: center; }
    .player-placeholder-icon { width: 56px; height: 56px; font-size: 26px; }
    .player-placeholder-text { font-size: 1rem; }
    .placeholder-info { margin-top: 12px; padding-top: 12px; }
    .placeholder-info span { font-size: 0.8125rem; }
    .placeholder-info span:last-child { font-size: 0.875rem; }

    .group-nav { margin-top: 12px; }
    .group-nav-link { font-size: 0.75rem; padding: 7px 12px; }

    .video-item {
        padding: 12px 14px;
        min-height: 48px;
        -webkit-tap-highlight-color: transparent;
    }

    .video-item-title {
        font-size: 0.8125rem;
        white-space: normal;
        overflow: visible;
        text-overflow: unset;
        display: -webkit-box;
        -webkit-line-clamp: 2;
        -webkit-box-orient: vertical;
    }
}

/* 手机竖屏窄幅：头部只保留校徽横幅，避免标题截断、logo 过小 */
@media (max-width: 560px) {
    .header-title { display: none; }
    .header-brand { gap: 10px; }
    .header-logo-link { flex: 1; min-width: 0; }
    .header-logo { height: 34px; max-width: 100%; }
}

/* 触屏设备：去除悬停粘滞，改用按压反馈 */
@media (hover: none) {
    .portal-card:hover {
        transform: none;
        border-color: var(--border);
        box-shadow: var(--shadow);
    }
    .portal-card:active { transform: scale(0.98); border-color: var(--primary); }
    .video-item:not(.active):hover { background: transparent; }
    .video-item:not(.active):active { background: var(--primary-light); }
}

@media (min-width: 769px) and (max-width: 1024px) {
    .main { padding: 20px; }
    :root { --sidebar-w: 280px; }
}

@media (min-width: 1025px) and (max-width: 1199px) {
    :root { --sidebar-w: 300px; }
}

@media (min-width: 1200px) {
    .main { padding: 32px 40px; }
}

/* Ultra-wide screens */
@media (min-width: 1600px) {
    :root { --sidebar-w: 360px; }
    .main { padding: 40px 60px; }
    .video-item-title { font-size: 0.9375rem; }
}

/* ===== Scrollbar Global ===== */
::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--border-bright); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--primary-dark); }



/* ===== Loading Skeleton ===== */
.skeleton {
    background: linear-gradient(90deg, #141d35 25%, #1e2a4a 50%, #141d35 75%);
    background-size: 200% 100%;
    animation: skeleton-loading 1.5s infinite;
    border-radius: 4px;
}

@keyframes skeleton-loading {
    0% { background-position: 200% 0; }
    100% { background-position: -200% 0; }
}

/* ============================================================
   六分组页面 + 门户首页
   ============================================================ */

/* Header 副标题 */
.header-heading { min-width: 0; }
.header-sub {
    font-size: 0.75rem;
    color: var(--text-muted);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    margin-top: 2px;
}
.header-logo-link { display: flex; align-items: center; }

/* 侧栏课程卡片（同旧版分组卡片风格） */
.side-card {
    margin: 12px 10px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 10px;
    overflow: hidden;
}

/* 侧栏组标题 */
.sidebar-group-head {
    padding: 14px 16px;
    border-bottom: 1px solid var(--border);
    background: linear-gradient(180deg, #1a2340 0%, #161e38 100%);
    text-align: center;
}
.sidebar-group-subject { margin-bottom: 8px; text-align: center; }
.subject-flag {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    font-size: 1rem;
    font-weight: 700;
    color: var(--primary);
    letter-spacing: 0.05em;
    position: relative;
    padding: 0 4px 7px;
}
.subject-flag::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 15%;
    right: 15%;
    height: 3px;
    background: linear-gradient(90deg, transparent, var(--primary), transparent);
    border-radius: 3px 3px 0 0;
}
.sidebar-group-title {
    font-size: 0.9rem;
    font-weight: 700;
    color: var(--primary);
    line-height: 1.4;
}
.sidebar-group-count {
    font-size: 0.72rem;
    color: var(--text-light);
    margin-top: 4px;
}

/* 同科目组导航 */
.group-nav {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
    margin-top: 16px;
}
.group-nav-link {
    padding: 6px 14px;
    border: 1px solid var(--border);
    border-radius: 20px;
    font-size: 0.8rem;
    color: var(--text-muted);
    background: var(--bg-card);
    text-decoration: none;
    transition: all var(--transition);
}
.group-nav-link:hover { border-color: var(--primary); color: var(--primary); text-decoration: none; }
.group-nav-link.active {
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    color: #0c1425;
    border-color: transparent;
    font-weight: 700;
}

/* ===== 内联 SVG 图标 ===== */
.icon-svg {
    width: 1em;
    height: 1em;
    vertical-align: -0.125em;
    flex-shrink: 0;
}
.portal-card-icon .icon-svg { width: 30px; height: 30px; vertical-align: middle; }

/* ===== Portal 首页 ===== */
.portal {
    max-width: 1080px;
    margin: 0 auto;
    /* 顶部须留出固定头部（--header-h，不透明）的高度，否则 banner 图标会被压在头部下方 */
    padding: calc(var(--header-h) + 12px) 20px 48px;
}

.portal-banner {
    text-align: center;
    padding: 20px 16px 32px;
}
.portal-banner-icon { font-size: 44px; line-height: 1.35; }
.portal-banner-title {
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--text);
    margin-top: 8px;
    letter-spacing: 0.03em;
}
.portal-banner-desc {
    color: var(--text-muted);
    font-size: 0.9rem;
    margin-top: 8px;
}

.portal-group { margin-bottom: 28px; }
.portal-group-head {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 12px;
    padding: 0 4px;
}
.portal-group-badge {
    display: inline-flex;
    align-items: center;
    gap: 5px;
    padding: 3px 12px;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 700;
}
.portal-group-count { font-size: 0.78rem; color: var(--text-muted); }

.portal-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(min(260px, 100%), 1fr));
    gap: 16px;
}

.portal-card {
    display: block;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 14px;
    padding: 20px;
    color: var(--text);
    text-decoration: none;
    -webkit-tap-highlight-color: transparent;
    touch-action: manipulation;
    transition: transform 0.25s ease, border-color 0.25s ease, box-shadow 0.25s ease;
}
.portal-card:hover {
    transform: translateY(-4px);
    border-color: var(--primary);
    box-shadow: var(--shadow-lg), 0 0 0 1px rgba(201,168,76,0.2);
    text-decoration: none;
}
.portal-card-icon { font-size: 30px; color: var(--primary); }
.portal-card-title {
    font-size: 1rem;
    font-weight: 700;
    margin: 10px 0 6px;
    color: var(--primary);
    line-height: 1.45;
}
.portal-card-desc {
    font-size: 0.78rem;
    color: var(--text-muted);
    line-height: 1.6;
    min-height: 2.4em;
}
.portal-card-count {
    display: inline-block;
    margin-top: 12px;
    padding: 2px 10px;
    border-radius: 12px;
    background: var(--bg-elevated);
    border: 1px solid var(--border);
    font-size: 0.72rem;
    color: var(--text-muted);
}

.portal-promo {
    margin-top: 36px;
    padding: 18px;
    border: 1px dashed var(--border-bright);
    border-radius: 12px;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 6px;
    color: var(--text-muted);
    font-size: 0.9rem;
}
.portal-promo-hot { color: var(--primary); font-weight: 700; font-size: 1rem; }

.portal-footer {
    text-align: center;
    padding: 18px;
    border-top: 1px solid var(--border);
    color: var(--text-light);
    font-size: 0.8rem;
}

@media (max-width: 768px) {
    .header-sub { display: none; }
    .portal { padding: calc(var(--header-h) + 8px) 14px 36px; }
    .portal-banner { padding: 12px 8px 20px; }
    .portal-banner-title { font-size: 1.2rem; }
    .portal-banner-desc { font-size: 0.85rem; }
    .portal-card { padding: 16px; }
    .portal-card-title { font-size: 0.9375rem; }
    .portal-promo { font-size: 0.84rem; padding: 14px; }
    .group-nav { margin-top: 10px; }
    .group-nav-link { font-size: 0.72rem; padding: 5px 10px; }
}