/* ============================================================
   COURSE LANDING PAGE STYLES
   ============================================================ */

:root {
    --bg-primary: #ffffff;
    --bg-secondary: #f8f9fb;
    --bg-card: #f4f5f8;
    --bg-hover: #e8ebf0;
    --text-primary: #1a1d2e;
    --text-secondary: #4a5068;
    --text-muted: #8891a5;
    --accent: #4366e0;
    --accent-hover: #5a7ef0;
    --accent-dim: rgba(67, 102, 224, 0.10);
    --border: #e2e5eb;
    --border-light: #d1d5de;
    --green: #16a34a;
    --orange: #ea580c;
    --radius: 10px;
    --radius-lg: 16px;
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-mono: 'JetBrains Mono', 'Fira Code', monospace;
}

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

body {
    font-family: var(--font-sans);
    color: var(--text-primary);
    background: var(--bg-primary);
    -webkit-font-smoothing: antialiased;
    min-height: 100vh;
}

/* ---- Header ---- */
.course-header {
    background: linear-gradient(135deg, #1a1d2e 0%, #2d3352 100%);
    color: #fff;
    padding: 60px 24px 48px;
    text-align: center;
}

.course-header h1 {
    font-size: 36px;
    font-weight: 700;
    margin-bottom: 10px;
    letter-spacing: -0.5px;
}

.course-header .subtitle {
    font-size: 16px;
    color: rgba(255,255,255,0.65);
    font-weight: 400;
    max-width: 600px;
    margin: 0 auto;
    line-height: 1.6;
}

.course-header .badge {
    display: inline-block;
    background: rgba(255,255,255,0.12);
    border: 1px solid rgba(255,255,255,0.2);
    border-radius: 20px;
    padding: 4px 14px;
    font-size: 12px;
    font-weight: 500;
    color: rgba(255,255,255,0.8);
    margin-bottom: 16px;
}

/* ---- Container ---- */
.container {
    max-width: 900px;
    margin: 0 auto;
    padding: 40px 24px 80px;
}

.section-title {
    font-size: 13px;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--text-muted);
    margin-bottom: 20px;
}

/* ---- Lecture Cards ---- */
.lecture-list {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.lecture-card {
    display: flex;
    align-items: stretch;
    background: var(--bg-primary);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    overflow: hidden;
    transition: box-shadow 0.25s ease, border-color 0.25s ease;
    text-decoration: none;
    color: inherit;
}

.lecture-card:hover {
    border-color: var(--accent);
    box-shadow: 0 4px 20px rgba(67, 102, 224, 0.1);
}

.lecture-card.disabled {
    opacity: 0.5;
    pointer-events: none;
}

.lecture-number {
    display: flex;
    align-items: center;
    justify-content: center;
    min-width: 72px;
    background: var(--bg-secondary);
    border-right: 1px solid var(--border);
    font-size: 28px;
    font-weight: 700;
    color: var(--text-muted);
    font-variant-numeric: tabular-nums;
}

.lecture-card:hover .lecture-number {
    color: var(--accent);
    background: var(--accent-dim);
}

.lecture-body {
    flex: 1;
    padding: 20px 24px;
}

.lecture-body h3 {
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 6px;
    color: var(--text-primary);
}

.lecture-body .desc {
    font-size: 13px;
    color: var(--text-secondary);
    line-height: 1.6;
    margin-bottom: 10px;
}

.lecture-meta {
    display: flex;
    gap: 16px;
    font-size: 12px;
    color: var(--text-muted);
}

.lecture-meta span {
    display: flex;
    align-items: center;
    gap: 4px;
}

.lecture-card .arrow {
    display: flex;
    align-items: center;
    justify-content: center;
    min-width: 48px;
    color: var(--text-muted);
    font-size: 20px;
    transition: color 0.25s;
}

.lecture-card:hover .arrow { color: var(--accent); }

/* ---- Coming Soon ---- */
.coming-soon {
    text-align: center;
    padding: 40px 20px;
    color: var(--text-muted);
    border: 2px dashed var(--border-light);
    border-radius: var(--radius-lg);
    margin-top: 16px;
}

.coming-soon .icon { font-size: 32px; margin-bottom: 8px; }
.coming-soon p { font-size: 14px; }

/* ---- Footer ---- */
.course-footer {
    text-align: center;
    padding: 24px;
    font-size: 12px;
    color: var(--text-muted);
    border-top: 1px solid var(--border);
}

/* ---- Loading ---- */
.loading {
    text-align: center;
    padding: 60px 20px;
    color: var(--text-muted);
    font-size: 14px;
}

/* ---- Responsive ---- */
@media (max-width: 600px) {
    .course-header { padding: 40px 16px 32px; }
    .course-header h1 { font-size: 26px; }
    .container { padding: 24px 16px 60px; }
    .lecture-number { min-width: 56px; font-size: 22px; }
    .lecture-body { padding: 14px 16px; }
    .lecture-body h3 { font-size: 16px; }
}