/* CSS Variables - Light Theme */
:root {
    --bg-primary: #ffffff;
    --bg-secondary: #f8fafc;
    --bg-tertiary: #f0fdfa;
    --card-bg: #ffffff;
    --card-bg-hover: #ffffff;
    --text-primary: #111827;
    --text-secondary: #64748b;
    --text-muted: #64748b;
    --border-color: #e2e8f0;
    --border-color-light: #f1f5f9;
    --primary: #14b8a6;
    --primary-hover: #0d9488;
    --primary-light: #f0fdfa;
    --accent-blue: #3b82f6;
    --accent-purple: #8b5cf6;
    --success: #10b981;
    --warning: #f59e0b;
    --danger: #ef4444;
    --shadow-sm: 0 1px 2px rgba(0,0,0,0.04);
    --shadow: 0 4px 12px rgba(0,0,0,0.05);
    --shadow-lg: 0 12px 32px rgba(0,0,0,0.08);
    --radius: 14px;
    --radius-sm: 10px;
}

/* ========== Reset & Base ========== */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; font-size: 16px; }
body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Microsoft YaHei", sans-serif;
    color: var(--text-primary);
    background: var(--bg-primary);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
}
a { text-decoration: none; color: inherit; transition: all 0.25s ease; }
ul { list-style: none; }
img { max-width: 100%; display: block; }
.container { max-width: 1200px; margin: 0 auto; padding: 0 20px; }

/* ========== Header ========== */
.site-header {
    background: rgba(255,255,255,0.85);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 1000;
    backdrop-filter: blur(12px);
}
.header-inner {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    height: 64px;
    display: flex;
    align-items: center;
    justify-content: space-between;
}
.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 20px;
    font-weight: 800;
    color: var(--text-primary);
}
.logo-icon {
    width: 38px; height: 38px;
    background: linear-gradient(135deg, #14b8a6, #0d9488);
    border-radius: 10px;
    display: flex; align-items: center; justify-content: center;
    color: #fff; font-size: 18px;
}
.logo-icon svg { width: 22px; height: 22px; display: block; }
.logo span { color: var(--text-primary); }
.logo span span { color: #0d9488; }

.main-nav { display: flex; gap: 2px; }
.main-nav a {
    padding: 8px 16px;
    border-radius: 8px;
    font-size: 14px;
    font-weight: 500;
    color: var(--text-secondary);
}
.main-nav a:hover, .main-nav a.active {
    color: var(--primary);
    background: var(--primary-light);
}

.header-right { display: flex; align-items: center; gap: 10px; }
.btn-login {
    padding: 8px 18px;
    border-radius: 8px;
    font-size: 14px;
    font-weight: 600;
    color: var(--primary);
}
.btn-login:hover { background: var(--primary-light); }
.btn-register {
    padding: 8px 18px;
    border-radius: 8px;
    background: linear-gradient(135deg, #14b8a6, #0d9488);
    color: #fff !important;
    font-size: 14px;
    font-weight: 600;
    box-shadow: 0 2px 8px rgba(20,184,166,0.25);
}
.btn-register:hover { transform: translateY(-1px); box-shadow: 0 4px 12px rgba(20,184,166,0.35); }

.user-menu { display: flex; align-items: center; gap: 8px; }
.user-avatar {
    width: 34px; height: 34px;
    border-radius: 50%;
    background: linear-gradient(135deg, #14b8a6, #3b82f6);
    color: #fff;
    display: flex; align-items: center; justify-content: center;
    font-weight: 700; font-size: 14px;
}

/* Mobile menu */
.mobile-toggle {
    display: none;
    width: 40px; height: 40px;
    border: none; border-radius: 10px;
    background: var(--bg-secondary); color: var(--text-secondary);
    font-size: 18px; cursor: pointer;
}
.mobile-nav {
    display: none;
    position: absolute;
    top: 64px; left: 0; right: 0;
    background: rgba(255,255,255,0.98);
    border-bottom: 1px solid var(--border-color);
    padding: 8px 0;
    box-shadow: 0 8px 24px rgba(0,0,0,0.06);
}
.mobile-nav.show { display: flex; flex-direction: column; }
.mobile-nav a {
    padding: 12px 24px;
    font-size: 15px; color: var(--text-secondary);
}

/* ========== Hero ========== */
.hero {
    background: linear-gradient(135deg, #ffffff 0%, #f0fdfa 40%, #e0f2fe 70%, #f0fdfa 100%);
    color: #111827;
    padding: 80px 0;
    position: relative;
    overflow: hidden;
}
.hero-bg-animation {
    position: absolute; inset: 0;
    overflow: hidden;
    pointer-events: none;
}
.particle {
    position: absolute;
    border-radius: 50%;
    opacity: 0.12;
}
.particle-1 {
    width: 500px; height: 500px;
    background: rgba(20,184,166,0.15);
    top: -200px; right: -100px;
    animation: float 8s ease-in-out infinite;
}
.particle-2 {
    width: 400px; height: 400px;
    background: rgba(59,130,246,0.12);
    bottom: -150px; left: -100px;
    animation: float 10s ease-in-out infinite reverse;
}
.particle-3 {
    width: 300px; height: 300px;
    background: rgba(16,185,129,0.1);
    top: 50%; left: 50%;
    animation: float 6s ease-in-out infinite;
}
@keyframes float {
    0%, 100% { transform: translate(0, 0); }
    50% { transform: translate(30px, -30px); }
}
.hero-content {
    position: relative; z-index: 1;
    display: flex;
    align-items: center;
    gap: 60px;
}
.hero-text { flex: 1; }
.hero-tag {
    display: inline-flex; align-items: center; gap: 6px;
    padding: 6px 14px;
    background: #f0fdfa;
    border: 1px solid rgba(20,184,166,0.25);
    border-radius: 50px;
    font-size: 13px;
    margin-bottom: 20px;
    color: #0f766e;
}
.hero-text h1 {
    font-size: 48px;
    font-weight: 900;
    line-height: 1.15;
    margin-bottom: 18px;
}
.hero-text h1 span {
    background: linear-gradient(90deg, #14b8a6, #3b82f6, #8b5cf6);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}
.hero-text p {
    font-size: 16px;
    color: #64748b;
    line-height: 1.7;
    margin-bottom: 28px;
    max-width: 480px;
}
.hero-btns { display: flex; gap: 12px; margin-bottom: 36px; }
.btn {
    display: inline-flex; align-items: center; gap: 8px;
    padding: 12px 28px;
    border-radius: 12px;
    font-size: 15px;
    font-weight: 700;
    border: none; cursor: pointer;
    transition: all 0.25s;
}
.btn-primary {
    background: linear-gradient(135deg, #14b8a6, #0d9488);
    color: #fff;
    box-shadow: 0 4px 16px rgba(20,184,166,0.25);
}
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 8px 24px rgba(20,184,166,0.35); }
.btn-outline {
    background: #ffffff;
    border: 1.5px solid #e2e8f0;
    color: #111827;
}
.btn-outline:hover { background: #f8fafc; border-color: #14b8a6; color: #0d9488; }

.hero-stats { display: flex; align-items: center; gap: 28px; }
.stat { text-align: center; }
.stat-num { display: block; font-size: 28px; font-weight: 900; color: #111827; }
.stat-label { font-size: 13px; color: #64748b; }
.stat-divider { width: 1px; height: 36px; background: #e2e8f0; }

/* Hero Visual */
.hero-visual { flex-shrink: 0; }
.visual-card {
    width: 320px;
    background: rgba(255,255,255,0.85);
    border: 1px solid #e2e8f0;
    border-radius: 14px;
    overflow: hidden;
    backdrop-filter: blur(8px);
    box-shadow: 0 24px 48px rgba(0,0,0,0.08);
}
.visual-editor-bar {
    display: flex;
    align-items: center;
    gap: 6px;
    padding: 10px 14px;
    background: #f8fafc;
    border-bottom: 1px solid #e2e8f0;
}
.ve-dot { width: 11px; height: 11px; border-radius: 50%; flex-shrink: 0; }
.ve-filename { margin-left: 8px; font-size: 12px; color: #94a3b8; font-family: monospace; }
.visual-code { padding: 16px 18px; display: flex; flex-direction: column; gap: 9px; }
.vc-line { font-family: 'Consolas', 'Courier New', monospace; font-size: 13px; line-height: 1; }
.vc-kw  { color: #0d9488; }
.vc-reg { color: #2563eb; }
.vc-num { color: #ea580c; }
.vc-fn  { color: #0891b2; }
.vc-cm  { color: #64748b; font-style: italic; }
.vc-cursor { position: relative; }
.vc-cursor::after {
    content: '';
    display: inline-block;
    width: 7px; height: 14px;
    background: #0d9488;
    border-radius: 1px;
    margin-left: 3px;
    vertical-align: middle;
    animation: blink 1.1s step-end infinite;
}
@keyframes blink { 0%,100%{ opacity:1 } 50%{ opacity:0 } }

/* ========== Notice Bar ========== */
.notice-bar {
    background: linear-gradient(90deg, #f0fdfa, #e0f2fe);
    border-bottom: 1px solid #e2e8f0;
    padding: 10px 0;
}
.notice-inner {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 14px;
    color: #0f766e;
    justify-content: center;
}
.notice-inner i { color: #14b8a6; }

/* ========== Section Common ========== */
.section-categories, .section-courses, .section-articles, .section-features {
    padding: 56px 0;
}
.section-head {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 28px;
}
.section-head h2 {
    font-size: 22px;
    font-weight: 800;
    display: flex; align-items: center; gap: 10px;
}
.section-head h2 i { color: #3b82f6; }
.section-head a {
    font-size: 14px;
    color: #3b82f6;
    font-weight: 600;
    display: flex; align-items: center; gap: 4px;
}
.section-head a:hover { gap: 8px; color: #0d9488; }
.section-head.center { justify-content: center; }

/* ========== Category Cards ========== */
.categories-grid {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: 14px;
}
.cat-card {
    background: #ffffff;
    border-radius: 14px;
    padding: 22px 16px;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 12px;
    border: 1.5px solid #e2e8f0;
    transition: all 0.3s;
    position: relative;
}
.cat-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 24px rgba(0,0,0,0.08);
    border-color: var(--clr);
}
.cat-icon-wrap {
    width: 50px; height: 50px;
    border-radius: 14px;
    display: flex; align-items: center; justify-content: center;
    color: #fff; font-size: 20px;
}
.cat-name { font-size: 14px; font-weight: 600; color: #111827; }
.cat-arrow { position: absolute; right: 14px; top: 50%; transform: translateY(-50%) translateX(4px); color: var(--clr); font-size: 12px; opacity: 0; transition: opacity 0.25s, transform 0.25s; }
.cat-card:hover .cat-arrow { opacity: 1; transform: translateY(-50%) translateX(0); }

/* 课程分类展开/折叠（带动画） */
.cat-toggle { cursor: pointer; user-select: none; }
.toggle-icon { margin-left: 6px; font-size: 14px; color: #64748b; transition: transform 0.35s ease; }
.cat-toggle.open .toggle-icon { transform: rotate(180deg); }
.categories-wrap {
    display: grid;
    grid-template-rows: 0fr;
    transition: grid-template-rows 0.35s ease, opacity 0.25s ease;
    opacity: 0;
}
.categories-wrap.open {
    grid-template-rows: 1fr;
    opacity: 1;
}
.categories-grid { min-height: 0; overflow: hidden; }

/* ========== Course Cards ========== */
.courses-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 20px;
}
.course-card {
    background: #ffffff;
    border-radius: 16px;
    overflow: hidden;
    border: 1.5px solid #e2e8f0;
    transition: all 0.3s;
    cursor: pointer;
    box-shadow: 0 4px 12px rgba(0,0,0,0.04);
}
.course-card:hover {
    transform: translateY(-6px);
    box-shadow: 0 12px 32px rgba(0,0,0,0.3);
    border-color: #3b82f6;
}
.course-cover {
    height: 150px;
    display: flex; align-items: center; justify-content: center;
    position: relative;
    overflow: hidden;
}
.course-cover-icon { font-size: 44px; color: rgba(255,255,255,0.85); }
.course-badge {
    position: absolute; top: 10px; right: 10px;
    padding: 4px 10px;
    border-radius: 6px;
    font-size: 11px; font-weight: 700;
    color: #fff;
}
.course-badge.free { background: rgba(16,185,129,0.9); }
.course-badge.vip { background: rgba(245,158,11,0.9); }
.course-cover-overlay {
    position: absolute; inset: 0;
    background: rgba(255,255,255,0.75);
    display: flex; align-items: center; justify-content: center;
    opacity: 0;
    transition: opacity 0.3s;
}
.course-card:hover .course-cover-overlay { opacity: 1; }
.course-cover-overlay span { color: #0f766e; font-size: 14px; font-weight: 600; }
.course-info { padding: 16px; }

/* 文字封面 */
.course-cover, .card-cover { position: relative; }
.cover-noise {
    position: absolute; inset: 0;
    background-image:
        radial-gradient(circle at 20% 30%, rgba(20,184,166,0.06) 1px, transparent 1px),
        radial-gradient(circle at 80% 20%, rgba(59,130,246,0.04) 1px, transparent 1px),
        radial-gradient(circle at 60% 80%, rgba(20,184,166,0.05) 1px, transparent 1px);
    background-size: 50px 50px, 70px 70px, 90px 90px;
    opacity: 0.6;
    z-index: 1;
}
.cover-glow {
    position: absolute;
    width: 120px; height: 120px;
    border-radius: 50%;
    background: rgba(20,184,166,0.15);
    filter: blur(35px);
    top: 50%; left: 50%;
    transform: translate(-50%, -50%);
    z-index: 1;
}
.cover-text {
    position: relative;
    z-index: 2;
    text-align: center;
    padding: 0 14px;
    max-width: 100%;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    transform: translateY(0);
    transition: transform 0.3s ease;
}
.course-card:hover .cover-text {
    transform: translateY(-3px);
}
.cover-cat {
    display: inline-block;
    font-size: 10px;
    font-weight: 600;
    color: #0f766e;
    background: rgba(255,255,255,0.85);
    padding: 3px 10px;
    border-radius: 12px;
    margin-bottom: 8px;
    letter-spacing: 1px;
    text-transform: uppercase;
}
.cover-title {
    font-size: 16px;
    font-weight: 800;
    color: #111827;
    line-height: 1.35;
    margin: 0;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}
.course-info h3 {
    font-size: 15px; font-weight: 700;
    line-height: 1.4;
    margin-bottom: 8px;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
    color: #111827;
}
.course-meta {
    display: flex; justify-content: space-between;
    font-size: 12px; color: #94a3b8;
}
/* 封面顶部 QQ 咨询小标签 */
.cover-qq {
    position: absolute;
    top: 10px; left: 10px;
    z-index: 5;
    display: flex; flex-direction: column; align-items: flex-start; gap: 1px;
    padding: 5px 10px;
    border-radius: 10px;
    background: rgba(255,255,255,0.92);
    border: 1px solid rgba(20,184,166,0.25);
    color: #64748b;
    font-size: 11px;
    line-height: 1.35;
    cursor: pointer;
    user-select: none;
    backdrop-filter: blur(6px);
    box-shadow: 0 2px 8px rgba(0,0,0,0.08);
    max-width: 140px;
    transition: all 0.2s ease;
}
.cover-qq i { color: #14b8a6; font-size: 10px; margin-right: 4px; }
.cover-qq b { color: #f59e0b; font-weight: 700; font-size: 12px; }
.cover-qq:hover { background: #ffffff; border-color: #14b8a6; transform: translateY(-1px); }
.cover-qq-right { left: auto; right: 10px; align-items: flex-end; text-align: right; }

/* ========== Article List ========== */
.articles-list { display: flex; flex-direction: column; gap: 10px; }
.article-card {
    background: #ffffff;
    border-radius: 12px;
    padding: 18px 22px;
    display: flex;
    align-items: center;
    gap: 18px;
    border: 1.5px solid #e2e8f0;
    transition: all 0.25s;
    box-shadow: 0 2px 8px rgba(0,0,0,0.04);
}
.article-card:hover {
    border-color: #3b82f6;
    box-shadow: 0 4px 12px rgba(0,0,0,0.25);
    transform: translateX(4px);
}
.article-num {
    width: 42px; height: 42px;
    border-radius: 10px;
    background: linear-gradient(135deg, #3b82f6, #8b5cf6);
    color: #fff;
    display: flex; align-items: center; justify-content: center;
    font-weight: 800; font-size: 16px;
    flex-shrink: 0;
}
.article-body { flex: 1; min-width: 0; }
.article-body h3 {
    font-size: 15px; font-weight: 600;
    color: #111827;
    margin-bottom: 4px;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}
.article-meta {
    display: flex; gap: 14px;
    font-size: 12px; color: #64748b;
}
.article-meta .vip-tag {
    color: #f59e0b; font-weight: 600;
}
.article-card > .fa-chevron-right { color: #94a3b8; font-size: 14px; }

/* ========== Features ========== */
.features-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 20px;
}
.feat-card {
    background: #ffffff;
    border-radius: 16px;
    padding: 32px 20px;
    text-align: center;
    border: 1.5px solid #e2e8f0;
    transition: all 0.3s;
}
.feat-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 24px rgba(0,0,0,0.07);
}
.feat-icon {
    width: 56px; height: 56px;
    border-radius: 14px;
    display: flex; align-items: center; justify-content: center;
    color: #fff; font-size: 24px;
    margin: 0 auto 16px;
}
.feat-card h3 { font-size: 16px; font-weight: 700; color: #111827; margin-bottom: 8px; }
.feat-card p { font-size: 13px; color: #64748b; line-height: 1.6; }

/* ========== Footer ========== */
.site-footer {
    background: #f8fafc;
    color: #64748b;
    padding: 56px 0 24px;
    margin-top: 48px;
    border-top: 1px solid #e2e8f0;
}
.footer-inner { max-width: 1200px; margin: 0 auto; padding: 0 20px; }
.footer-grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: 40px;
    margin-bottom: 36px;
}
.footer-logo {
    display: flex; align-items: center; gap: 8px;
    font-size: 20px; font-weight: 800;
    color: #111827;
    margin-bottom: 14px;
}
.footer-logo .logo-icon { width: 32px; height: 32px; font-size: 15px; border-radius: 8px; }
.footer-desc { font-size: 14px; line-height: 1.7; margin-bottom: 18px; }
.footer-social { display: flex; gap: 10px; }
.footer-social a {
    width: 36px; height: 36px;
    border-radius: 10px;
    background: #f1f5f9;
    display: flex; align-items: center; justify-content: center;
    color: #64748b; font-size: 15px;
    transition: all 0.2s;
}
.footer-social a:hover { background: #14b8a6; color: #fff; }
.footer-col h4 { color: #111827; font-size: 15px; font-weight: 700; margin-bottom: 16px; }
.footer-col a {
    display: flex; align-items: center; gap: 6px;
    font-size: 14px; color: #64748b;
    padding: 5px 0;
}
.footer-col a:hover { color: #14b8a6; }
.footer-bottom {
    border-top: 1px solid #e2e8f0;
    padding-top: 20px;
    text-align: center;
    font-size: 13px; color: #64748b;
}

.footer-icp {
    margin-top: 6px;
    font-size: 12px;
    color: #64748b;
}

.footer-icp a {
    color: #64748b;
    text-decoration: none;
    transition: color 0.2s;
}

.footer-icp a:hover {
    color: #14b8a6;
}

.footer-admin-link {
    display: inline-block;
    margin-top: 8px;
    width: 22px; height: 22px;
    line-height: 22px;
    font-size: 11px;
    font-weight: 700;
    color: #64748b;
    background: #e2e8f0;
    border-radius: 4px;
    text-decoration: none;
    opacity: 0.5;
    transition: opacity 0.2s;
}

.footer-admin-link:hover {
    opacity: 1;
    color: #14b8a6;
}

/* ===== 课程大纲样式 ===== */
.course-syllabus { padding: 0; margin: 0; }
.syllabus-section { margin-bottom: 28px; background:#ffffff; border-radius:12px; overflow:hidden; border:1px solid #e2e8f0; box-shadow: 0 2px 8px rgba(0,0,0,0.04); }
.syllabus-section-header { display:flex;align-items:center;gap:10px; padding:14px 20px; background:linear-gradient(135deg,#14b8a6,#0d9488); color:#fff; cursor:pointer; transition:opacity 0.2s; }
.syllabus-section-header:hover { opacity:0.92; }
.syllabus-section-header .section-icon { width:36px;height:36px;border-radius:10px;background:rgba(255,255,255,0.18);display:flex;align-items:center;justify-content:center;font-size:15px;flex-shrink:0; }
.syllabus-section-header h3 { margin:0; font-size:15px; font-weight:700; flex:1; }
.syllabus-section-header .section-count { font-size:12px;background:rgba(255,255,255,0.22);padding:3px 10px;border-radius:12px;font-weight:600; }
.syllabus-lesson-list { list-style:none;padding:0;margin:0; }
.syllabus-lesson-list li { display:flex;align-items:center;gap:12px; padding:11px 20px 11px 20px; border-bottom:1px solid #e2e8f0; font-size:14px;color:#64748b; transition:background 0.15s; line-height:1.5; }
.syllabus-lesson-list li:last-child { border-bottom:none; }
.syllabus-lesson-list li:hover { background:rgba(59,130,246,0.08); }
.syllabus-lesson-num { width:28px;height:28px;border-radius:8px;background:#e2e8f0;color:#22d3ee;display:flex;align-items:center;justify-content:center;font-size:12px;font-weight:700;flex-shrink:0; }
.syllabus-lesson-text { flex:1; }
.syllabus-badge { font-size:11px;padding:2px 9px;border-radius:5px;font-weight:600;flex-shrink:0; }
.syllabus-badge.new { background:#dcfce7;color:#16a34a; }
.syllabus-badge.hot { background:#fef3c7;color:#d97706; }
.syllabus-badge.update { background:#dbeafe;color:#2563eb; }

/* 课程信息卡片 */
.course-info-cards { display:grid; grid-template-columns:repeat(auto-fit,minmax(220px,1fr)); gap:16px; margin-bottom:24px; }
.course-info-card { background:#ffffff;border-radius:12px;padding:18px;border:1px solid #e2e8f0;display:flex;align-items:center;gap:14px;transition:transform 0.2s,box-shadow 0.2s; box-shadow: 0 2px 8px rgba(0,0,0,0.04); }
.course-info-card:hover { transform:translateY(-2px); box-shadow:0 6px 20px rgba(0,0,0,0.08); }
.course-info-card-icon { width:46px;height:46px;border-radius:12px;display:flex;align-items:center;justify-content:center;font-size:18px;flex-shrink:0; }
.course-info-card-body h4 { margin:0 0 3px 0; font-size:13px;color:#64748b;font-weight:500; }
.course-info-card-body p { margin:0; font-size:17px;font-weight:800;color:#111827; }

/* 课程特色标签 */
.course-tags { display:flex;flex-wrap:wrap;gap:8px; margin-bottom:24px; }
.course-tag { display:inline-flex;align-items:center;gap:5px;padding:7px 16px;border-radius:20px;font-size:13px;font-weight:600;border:1px solid #e2e8f0;background:rgba(34,211,238,0.08);color:#22d3ee; }
.course-tag i { font-size:12px; }

/* 响应式 */
@media(max-width:768px) {
    .course-info-cards { grid-template-columns:1fr 1fr; }
    .syllabus-section-header { padding:12px 16px; }
    .syllabus-section-header h3 { font-size:14px; }
    .syllabus-lesson-list li { padding:10px 16px; font-size:13.5px; }
}
@media(max-width:480px) {
    .course-info-cards { grid-template-columns:1fr; }
}

/* ========== Profile Page ========== */
.profile-grid { grid-template-columns: 2fr 1fr; }
.profile-card {
    background: #ffffff;
    border-radius: 16px;
    padding: 28px;
    border: 1.5px solid #e2e8f0;
    box-shadow: 0 2px 8px rgba(0,0,0,0.04);
}
.profile-avatar {
    width: 56px; height: 56px;
    border-radius: 50%;
    background: linear-gradient(135deg, #3b82f6, #8b5cf6);
    color: #fff;
    display: flex; align-items: center; justify-content: center;
    font-size: 22px; font-weight: 800;
    flex-shrink: 0;
}
.profile-stats {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 14px;
}
.profile-stat-item {
    background: #f8fafc;
    border-radius: 12px;
    padding: 16px;
    border: 1px solid #f1f5f9;
}
.profile-stat-label {
    display: block;
    font-size: 13px;
    color: #64748b;
    margin-bottom: 6px;
}
.profile-stat-value {
    font-size: 17px;
    font-weight: 700;
    color: #111827;
}
.profile-actions {
    display: flex;
    flex-direction: column;
    gap: 10px;
}
.profile-btn {
    display: block;
    width: 100%;
    text-align: center;
    padding: 11px 0;
    border-radius: 10px;
    font-size: 14px;
    font-weight: 600;
    color: #64748b;
    background: #e2e8f0;
    border: 1px solid #e2e8f0;
    transition: all 0.2s;
}
.profile-btn:hover {
    background: #28395c;
    border-color: #3b82f6;
}
.profile-btn-primary {
    background: linear-gradient(135deg, #3b82f6, #8b5cf6) !important;
    color: #fff !important;
    border: none !important;
    box-shadow: 0 2px 10px rgba(59,130,246,0.3);
}
.profile-btn-primary:hover {
    transform: translateY(-1px);
    box-shadow: 0 4px 16px rgba(59,130,246,0.4);
}
.profile-btn-admin {
    background: #fef2f2 !important;
    color: #dc2626 !important;
    border-color: #fecaca !important;
}
.profile-btn-admin:hover {
    background: #fee2e2 !important;
    border-color: #fca5a5 !important;
}
.profile-btn-danger {
    color: #64748b !important;
}
.profile-btn-danger:hover {
    background: #fef2f2 !important;
    color: #dc2626 !important;
    border-color: #fecaca !important;
}
.profile-security-box {
    background: #f0fdfa;
    border-left: 4px solid #14b8a6;
    padding: 18px 22px;
    border-radius: 0 12px 12px 0;
    font-size: 14px;
}

@media (max-width: 768px) {
    .profile-grid { grid-template-columns: 1fr; }
    .profile-stats { grid-template-columns: 1fr 1fr; }
    .profile-card { padding: 20px; }
}
@media (max-width: 480px) {
    .profile-stats { grid-template-columns: 1fr; }
}

/* Back to top */
.back-top {
    position: fixed;
    bottom: 28px; right: 28px;
    width: 44px; height: 44px;
    border-radius: 14px;
    border: none;
    background: linear-gradient(135deg, #14b8a6, #0d9488);
    color: #fff; font-size: 18px;
    cursor: pointer;
    opacity: 0; visibility: hidden;
    transform: translateY(10px);
    transition: all 0.3s;
    box-shadow: 0 4px 12px rgba(20,184,166,0.25);
    z-index: 900;
}
.back-top.show { opacity: 1; visibility: visible; transform: translateY(0); }
.back-top:hover { transform: translateY(-3px); }

/* ========== Responsive ========== */
@media (max-width: 1024px) {
    .courses-grid { grid-template-columns: repeat(3, 1fr); }
    .categories-grid { grid-template-columns: repeat(3, 1fr); }
    .features-grid { grid-template-columns: repeat(2, 1fr); }
    .footer-grid { grid-template-columns: repeat(2, 1fr); }
    .hero-visual { display: none; }
}
@media (max-width: 768px) {
    .main-nav, .header-right .btn-login, .header-right .btn-register, .header-right .user-menu { display: none; }
    .mobile-toggle { display: flex; }
    .hero-text h1 { font-size: 30px; }
    .hero-btns { flex-direction: column; }
    .hero-stats { gap: 16px; }
    .stat-num { font-size: 22px; }
    .courses-grid { grid-template-columns: repeat(2, 1fr); gap: 12px; }
    .categories-grid { grid-template-columns: repeat(2, 1fr); }
    .features-grid { grid-template-columns: 1fr; }
    .footer-grid { grid-template-columns: 1fr; gap: 28px; }
    .section-categories, .section-courses, .section-articles, .section-features { padding: 36px 0; }
}
@media (max-width: 480px) {
    .courses-grid { grid-template-columns: 1fr; }
}

/* ========== Course Buy Button & Modal ========== */
.course-actions {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-top: 14px;
    padding-top: 14px;
    border-top: 1px solid #f1f5f9;
    gap: 12px;
}

.course-price {
    font-size: 18px;
    font-weight: 900;
    color: #ef4444;
    text-shadow: 0 1px 2px rgba(239, 68, 68, 0.15);
}

/* ========== 折扣价格（大众点评/美团风格 — 单行紧凑） ========== */
.price-compact {
    display: inline-flex;
    align-items: baseline;
    gap: 6px;
    flex-wrap: wrap;
    vertical-align: middle;
    line-height: 1.2;
}

/* 原价 ¥480 */
.price-orig {
    font-size: 12px;
    font-weight: 500;
    color: #94a3b8;
    position: relative;
    display: inline-block;
    line-height: 1;
}
.price-orig::after {
    content: '';
    position: absolute;
    left: -2px; right: -2px;
    top: 50%;
    height: 1.5px;
    background: #94a3b8;
    border-radius: 1px;
}

/* 折扣角标 7.7折 — 紧贴原价 */
.discount-tag {
    display: inline-flex;
    align-items: center;
    font-size: 10px;
    font-weight: 700;
    color: #fff;
    background: linear-gradient(135deg, #ff5757, #e53935);
    padding: 1px 5px;
    border-radius: 3px 3px 3px 0;
    line-height: 1.6;
    letter-spacing: 0;
    box-shadow: 0 1px 3px rgba(229, 57, 53, 0.3);
    vertical-align: middle;
    position: relative;
    transform: translateY(-3px);
}

/* 现价 ¥369 */
.price-cur {
    font-size: 20px;
    font-weight: 900;
    color: #e53935;
    line-height: 1;
    text-shadow: 0 1px 2px rgba(229, 57, 53, 0.12);
    margin-left: 2px;
    letter-spacing: -0.3px;
}
.price-cur .price-symbol {
    font-size: 13px;
    font-weight: 700;
    margin-right: 1px;
}

.course-price.vip-text { color: #f59e0b; font-weight: 800; }
.course-price.free-text { color: #10b981; font-weight: 800; }

/* ========== 全场促销横幅（标题栏旁） ========== */
.promo-banner-inline {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    background: linear-gradient(135deg, #fef2f2, #fee2e2);
    border: 1px solid #fecaca;
    border-radius: 8px;
    padding: 6px 14px;
    margin-left: 12px;
    font-size: 13px;
    vertical-align: middle;
}
.promo-banner-inline .promo-icon {
    color: #ef4444;
    font-size: 14px;
    animation: promoBounce 1s ease infinite;
}
@keyframes promoBounce {
    0%, 100% { transform: scale(1); }
    50%      { transform: scale(1.15); }
}
.promo-banner-inline .promo-text {
    color: #dc2626;
    font-weight: 800;
    white-space: nowrap;
}
.promo-banner-inline .countdown-timer {
    display: inline-flex;
    align-items: center;
    gap: 2px;
    font-family: 'SF Mono', Consolas, monospace;
    font-size: 12px;
    font-weight: 700;
    color: #991b1b;
    background: #fef2f2;
    padding: 2px 6px;
    border-radius: 4px;
    border: 1px solid #fca5a5;
}
.promo-banner-inline .countdown-timer .cd-num {
    display: inline-block;
    min-width: 18px;
    text-align: center;
    background: linear-gradient(180deg, #dc2626, #b91c1c);
    color: #fff;
    border-radius: 3px;
    padding: 0 3px;
    line-height: 1.5;
}
.promo-banner-inline .countdown-timer .cd-sep {
    color: #f87171;
    font-weight: 400;
}

.btn-buy {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    border: none;
    border-radius: 50px;
    padding: 8px 18px;
    font-size: 13px;
    font-weight: 800;
    color: #fff;
    background: linear-gradient(135deg, #ef4444, #dc2626);
    cursor: pointer;
    box-shadow: 0 4px 10px rgba(239, 68, 68, 0.3), inset 0 1px 0 rgba(255,255,255,0.2);
    transition: transform 0.2s ease, box-shadow 0.2s ease, filter 0.2s ease;
    white-space: nowrap;
    letter-spacing: 0.5px;
}

.btn-buy i {
    font-size: 12px;
}

.btn-buy:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 16px rgba(239, 68, 68, 0.4);
    filter: brightness(1.08);
}

.btn-buy:active {
    transform: translateY(0);
}

.btn-buy-free {
    background: linear-gradient(135deg, #10b981, #059669);
    box-shadow: 0 4px 10px rgba(16, 185, 129, 0.3), inset 0 1px 0 rgba(255,255,255,0.2);
}

.btn-buy-free:hover { box-shadow: 0 6px 16px rgba(16, 185, 129, 0.4); }

.btn-buy-vip {
    background: linear-gradient(135deg, #f59e0b, #d97706);
    box-shadow: 0 4px 10px rgba(245, 158, 11, 0.3), inset 0 1px 0 rgba(255,255,255,0.2);
}

.btn-buy-vip:hover { box-shadow: 0 6px 16px rgba(245, 158, 11, 0.4); }

/* Buy Modal */
.buy-modal {
    position: fixed;
    inset: 0;
    z-index: 9999;
    background: rgba(15, 23, 42, 0.5);
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
    backdrop-filter: blur(4px);
}
.buy-modal-content {
    background: #ffffff;
    border-radius: 16px;
    width: 100%;
    max-width: 420px;
    box-shadow: 0 24px 48px rgba(0,0,0,0.12);
    overflow: hidden;
    animation: modalIn 0.25s ease-out;
}
@keyframes modalIn {
    from { opacity: 0; transform: translateY(20px) scale(0.96); }
    to { opacity: 1; transform: translateY(0) scale(1); }
}
.buy-modal-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 18px 20px;
    background: linear-gradient(135deg, #14b8a6, #0d9488);
    color: #fff;
}
.buy-modal-header h3 { margin: 0; font-size: 16px; }
.buy-modal-close {
    background: rgba(255,255,255,0.2);
    border: none;
    color: #fff;
    width: 30px;
    height: 30px;
    border-radius: 50%;
    font-size: 20px;
    line-height: 1;
    cursor: pointer;
    transition: background 0.2s;
}
.buy-modal-close:hover { background: rgba(255,255,255,0.35); }
.buy-modal-body { padding: 24px; text-align: center; }
.buy-course-title { font-size: 15px; font-weight: 700; color: #111827; margin: 0 0 8px; }
.buy-course-price { font-size: 14px; color: #64748b; margin: 0 0 18px; }
.buy-course-price strong { color: #e74c3c; font-size: 18px; }
.buy-qrcode {
    background: #f8fafc;
    border-radius: 12px;
    padding: 16px;
    margin-bottom: 16px;
    border: 1px solid #e2e8f0;
}
.buy-qrcode img {
    width: 180px;
    height: 180px;
    object-fit: contain;
    border-radius: 8px;
    background: #fff;
    border: 1px solid #e2e8f0;
}
.buy-qrcode-tip { margin: 10px 0 0; font-size: 13px; color: #64748b; }
.buy-instructions { font-size: 13px; color: #64748b; line-height: 1.8; }
.buy-instructions strong { color: #ef4444; }

@media (max-width: 480px) {
    .course-actions { flex-wrap: wrap; }
    .buy-modal-content { max-width: 100%; }
    .buy-qrcode img { width: 150px; height: 150px; }
}

/* ========== Hero Carousel ========== */
.hero-carousel {
    width: 340px;
    position: relative;
    border-radius: 20px;
    overflow: hidden;
    box-shadow: 0 32px 64px rgba(0,0,0,0.08);
    flex-shrink: 0;
}
.carousel-track {
    position: relative;
    width: 100%;
    height: 300px;
}
.carousel-slide {
    position: absolute;
    inset: 0;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 36px 28px;
    text-align: center;
    opacity: 0;
    transform: scale(0.96) translateY(8px);
    transition: opacity 0.55s ease, transform 0.55s ease;
    pointer-events: none;
}
.carousel-slide.active {
    opacity: 1;
    transform: scale(1) translateY(0);
    pointer-events: auto;
}
.slide-icon {
    width: 72px; height: 72px;
    border-radius: 20px;
    background: #f0fdfa;
    backdrop-filter: blur(8px);
    display: flex; align-items: center; justify-content: center;
    font-size: 32px;
    color: #14b8a6;
    margin-bottom: 18px;
    box-shadow: 0 8px 24px rgba(0,0,0,0.06);
}
.slide-title {
    font-size: 22px;
    font-weight: 900;
    color: #111827;
    margin-bottom: 8px;
}
.slide-sub {
    font-size: 13px;
    color: #64748b;
    margin-bottom: 20px;
    line-height: 1.5;
}
.slide-badge {
    display: inline-flex; align-items: center; gap: 6px;
    padding: 6px 16px;
    background: #f0fdfa;
    backdrop-filter: blur(6px);
    border-radius: 50px;
    font-size: 12px;
    font-weight: 700;
    color: #0f766e;
    border: 1px solid rgba(20,184,166,0.25);
}
.carousel-prev, .carousel-next {
    position: absolute;
    top: 50%; transform: translateY(-50%);
    width: 32px; height: 32px;
    border-radius: 50%;
    border: none;
    background: #ffffff;
    backdrop-filter: blur(6px);
    color: #64748b;
    font-size: 13px;
    cursor: pointer;
    transition: background 0.2s, transform 0.2s;
    z-index: 10;
    display: flex; align-items: center; justify-content: center;
    box-shadow: 0 2px 8px rgba(0,0,0,0.08);
}
.carousel-prev { left: 10px; }
.carousel-next { right: 10px; }
.carousel-prev:hover, .carousel-next:hover {
    background: #f0fdfa;
    color: #14b8a6;
    transform: translateY(-50%) scale(1.1);
}
.carousel-dots {
    position: absolute;
    bottom: 14px; left: 50%; transform: translateX(-50%);
    display: flex; gap: 6px;
    z-index: 10;
}
.c-dot {
    width: 7px; height: 7px;
    border-radius: 50%;
    background: #cbd5e1;
    cursor: pointer;
    transition: all 0.3s;
}
.c-dot.active {
    background: #14b8a6;
    width: 22px;
    border-radius: 4px;
}

/* ========== Section Visual Enhancements ========== */
.section-categories { background: #ffffff; }

.section-features {
    background: linear-gradient(135deg, #f8fafc 0%, #f0fdfa 50%, #ccfbf1 100%);
    padding: 72px 0;
    margin-top: 0;
}
.section-features .section-head h2 { color: #fff; }
.section-features .section-head h2 i { color: #818cf8; }

.feat-card {
    background: #ffffff;
    border: 1px solid #e2e8f0;
    backdrop-filter: blur(8px);
    color: #64748b;
    box-shadow: 0 4px 12px rgba(0,0,0,0.04);
}
.feat-card:hover {
    background: #ffffff;
    border-color: rgba(20,184,166,0.35);
    box-shadow: 0 12px 32px rgba(0,0,0,0.08);
    transform: translateY(-6px);
}
.feat-card h3 { color: #111827; }
.feat-card p { color: #64748b; }

/* Section divider accent */
.section-courses {
    background: #ffffff;
    padding: 60px 0;
}
.section-articles {
    background: #ffffff;
    padding: 60px 0;
}

/* Section head refinement */
.section-head h2 {
    font-size: 24px;
    position: relative;
}
.section-head h2::after {
    content: '';
    display: block;
    width: 40px; height: 3px;
    background: linear-gradient(90deg, #14b8a6, #3b82f6);
    border-radius: 2px;
    margin-top: 6px;
}

/* Category card refinement */
.cat-card {
    background: #ffffff;
    border: 1.5px solid #e2e8f0;
    box-shadow: 0 2px 8px rgba(0,0,0,0.04);
}
.cat-card:hover {
    box-shadow: 0 10px 28px rgba(0,0,0,0.06);
    border-color: #14b8a6;
}

/* Course card subtle border glow on hover */
.course-card:hover {
    border-color: #3b82f6;
    box-shadow: 0 16px 40px rgba(59,130,246,0.18);
}

/* Article card refinement */
.article-card:hover {
    border-color: #3b82f6;
    box-shadow: 0 6px 20px rgba(59,130,246,0.15);
}
.article-num {
    background: linear-gradient(135deg, #3b82f6, #6366f1);
}

/* Notice bar pulse icon */
.notice-inner i {
    animation: pulse-icon 2s ease-in-out infinite;
}
@keyframes pulse-icon {
    0%,100% { transform: scale(1); }
    50% { transform: scale(1.2); }
}

/* Hero carousel responsive */
@media (max-width: 1024px) {
    .hero-carousel { display: none; }
}
@media (max-width: 768px) {
    .section-features { padding: 48px 0; }
}

/* ========== Pagination ========== */
.pagination {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 6px;
    margin-top: 36px;
    flex-wrap: wrap;
}
.page-item {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 36px;
    height: 36px;
    padding: 0 10px;
    border-radius: 8px;
    font-size: 14px;
    font-weight: 600;
    color: #64748b;
    background: #ffffff;
    border: 1.5px solid #e2e8f0;
    transition: all 0.2s;
}
.page-item:hover {
    color: #14b8a6;
    border-color: #14b8a6;
    background: #f0fdfa;
    transform: translateY(-1px);
}
.page-item.active {
    background: linear-gradient(135deg, #14b8a6, #0d9488);
    color: #fff;
    border-color: transparent;
    box-shadow: 0 4px 12px rgba(20, 184, 166, 0.25);
}

/* ========== Extra Mobile Responsive Fixes ========== */
@media (max-width: 1024px) {
    .main-nav .btn-recommend { display: none; }
}
@media (max-width: 900px) {
    .header-inner { height: 58px; }
    .logo { font-size: 18px; gap: 8px; }
    .logo-icon { width: 34px; height: 34px; font-size: 16px; }
    .mobile-toggle { width: 38px; height: 38px; }
    .header-right .btn-admin { display: none; }
}
@media (max-width: 768px) {
    .hero { padding: 48px 0 56px; }
    .hero-content { flex-direction: column; gap: 36px; text-align: center; }
    .hero-text { width: 100%; }
    .hero-text h1 { font-size: 30px; margin-bottom: 14px; }
    .hero-text p { font-size: 15px; margin: 0 auto 24px; }
    .hero-btns { justify-content: center; flex-wrap: wrap; }
    .hero-stats { justify-content: center; flex-wrap: wrap; gap: 12px 24px; }
    .stat-divider { display: none; }
    .notice-inner { flex-wrap: wrap; justify-content: center; text-align: center; font-size: 12px; padding: 0 10px; gap: 6px; }
    .section-head { flex-direction: column; align-items: flex-start; gap: 10px; }
    .section-head h2 { font-size: 20px; }
    .section-categories, .section-courses, .section-articles, .section-features { padding: 36px 0; }
    .categories-grid { grid-template-columns: repeat(2, 1fr); gap: 12px; }
    .cat-card { padding: 18px 12px; }
    .cat-icon-wrap { width: 44px; height: 44px; font-size: 18px; }
    .cat-name { font-size: 13px; }
    .feat-card { padding: 24px 18px; }
    .article-card { flex-wrap: wrap; padding: 14px 16px; gap: 12px; }
    .article-body { min-width: 0; width: 100%; }
    .article-body h3 { white-space: normal; font-size: 14px; }
    .article-meta { flex-wrap: wrap; gap: 8px; }
    .article-card > .fa-chevron-right { display: none; }
    .footer-bottom { font-size: 12px; }
    .back-top { bottom: 18px; right: 18px; width: 40px; height: 40px; }
}
@media (max-width: 640px) {
    .courses-grid { grid-template-columns: 1fr; gap: 16px; }
    .categories-grid { grid-template-columns: repeat(2, 1fr); gap: 10px; }
    .cover-qq { font-size: 10px; padding: 4px 8px; max-width: 120px; }
    .cover-qq b { font-size: 11px; }
    .cover-qq i { font-size: 9px; margin-right: 3px; }
}
@media (max-width: 480px) {
    .container { padding: 0 14px; }
    .header-inner { padding: 0 14px; }
    .hero-text h1 { font-size: 26px; }
    .hero-btns { flex-direction: column; gap: 10px; }
    .hero-btns .btn { width: 100%; justify-content: center; }
    .hero-stats { gap: 8px 20px; }
    .stat-num { font-size: 22px; }
    .stat-label { font-size: 12px; }
    .section-head h2 { font-size: 18px; }
    .course-info { padding: 14px; }
    .course-info h3 { font-size: 14px; }
    .course-cover { height: 140px; }
    .cover-title { font-size: 15px; }
    .course-actions { flex-wrap: wrap; gap: 8px; }
    .btn-buy { flex: 1; justify-content: center; }
    .pagination { gap: 4px; }
    .page-item { min-width: 32px; height: 32px; font-size: 13px; }
    .cat-card { padding: 16px 10px; }
    .cat-icon-wrap { width: 40px; height: 40px; font-size: 16px; }
    .footer-grid { gap: 24px; }
}