/* ============================================================
   Course detail page — long-form editorial layout
   ============================================================ */

/* ============================================================
   Course switcher in hero (horizontal scroll list)
   ============================================================ */
.course-switcher {
    position: relative;
    margin: -8px -16px 36px;
    padding: 4px 0;
}
.cs-track {
    display: flex;
    gap: 8px;
    overflow-x: auto;
    padding: 6px 16px;
    scroll-behavior: smooth;
    scrollbar-width: none;
    -ms-overflow-style: none;
    scroll-snap-type: x proximity;
    -webkit-mask-image: linear-gradient(90deg, transparent 0, #000 24px, #000 calc(100% - 24px), transparent 100%);
            mask-image: linear-gradient(90deg, transparent 0, #000 24px, #000 calc(100% - 24px), transparent 100%);
}
.cs-track::-webkit-scrollbar { display: none; }

.cs-item {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    padding: 9px 14px 9px 9px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 999px;
    text-decoration: none;
    color: var(--text);
    flex-shrink: 0;
    transition: border-color 0.15s, background 0.15s, transform 0.1s;
    scroll-snap-align: center;
    white-space: nowrap;
}
.cs-item:hover {
    border-color: var(--border-strong);
    background: var(--bg-soft);
}
.cs-item:active { transform: translateY(1px); }
.cs-item.is-current {
    border-color: var(--accent);
    background: var(--brand-soft);
    box-shadow: 0 0 0 3px color-mix(in oklab, var(--accent) 12%, transparent);
}
.cs-badge {
    width: 28px;
    height: 28px;
    border-radius: 8px;
    display: grid;
    place-items: center;
    color: #fff;
    font-family: var(--mono);
    font-size: 12px;
    font-weight: 800;
    flex-shrink: 0;
}
.cs-badge.fam-python { background: linear-gradient(135deg, #3776ab, #4b8bbe); }
.cs-badge.fam-cpp    { background: linear-gradient(135deg, #00599c, #044f88); }
.cs-badge.fam-info   { background: linear-gradient(135deg, #8a5fd1, #6346b0); }

.cs-text {
    display: flex;
    flex-direction: column;
    gap: 1px;
    line-height: 1.15;
}
.cs-fam {
    font-family: var(--mono);
    font-size: 10px;
    font-weight: 700;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    color: var(--text-dim);
}
.cs-item.is-current .cs-fam { color: var(--brand-ink); }
.cs-level {
    font-size: 13px;
    font-weight: 700;
    letter-spacing: -0.005em;
    color: var(--text);
}

.cs-arrow {
    position: absolute;
    top: 50%;
    transform: translateY(-50%);
    width: 32px;
    height: 32px;
    border-radius: 50%;
    background: var(--bg-card);
    border: 1px solid var(--border);
    color: var(--text);
    display: grid;
    place-items: center;
    cursor: pointer;
    z-index: 5;
    padding: 0;
    transition: background 0.15s, color 0.15s, opacity 0.15s;
    box-shadow: var(--shadow-1);
}
.cs-arrow:hover { background: var(--accent); color: #fff; border-color: var(--accent); }
.cs-arrow.is-disabled {
    opacity: 0;
    pointer-events: none;
}
.cs-arrow svg { width: 14px; height: 14px; }
.cs-prev { left: -4px; }
.cs-next { right: -4px; }

@media (max-width: 700px) {
    .course-switcher { margin-left: 0; margin-right: 0; }
    .cs-prev, .cs-next { display: none; }
    .cs-track { padding-left: 4px; padding-right: 4px; }
}

/* ============================================================
   Course hero — entry animation
   ============================================================ */
@keyframes courseHeroEnter {
    from { opacity: 0; transform: translateY(14px); }
    to   { opacity: 1; transform: translateY(0); }
}
.course-hero-main > * {
    animation: courseHeroEnter 0.55s cubic-bezier(0.22, 1, 0.36, 1) both;
}
.course-hero-main .course-glyph { animation-delay: 0.02s; }
.course-hero-main .tags         { animation-delay: 0.08s; }
.course-hero-main h1            { animation-delay: 0.14s; }
.course-hero-main .subtitle     { animation-delay: 0.22s; }
.hero-side-card {
    animation: courseHeroEnter 0.6s cubic-bezier(0.22, 1, 0.36, 1) 0.16s both;
}
@media (prefers-reduced-motion: reduce) {
    .course-hero-main > *,
    .hero-side-card { animation: none; }
}

/* ---- Course hero ---- */
.course-hero {
    padding: 56px 0 64px;
    position: relative;
    overflow: hidden;
}
.course-hero::before {
    content: '';
    position: absolute;
    inset: 0;
    background:
        radial-gradient(55% 50% at 90% 0%, var(--course-tint, var(--lavender-soft)), transparent 65%),
        radial-gradient(40% 50% at 5% 100%, #f0e9d4, transparent 70%);
    pointer-events: none;
    z-index: 0;
}
.course-hero .container { position: relative; z-index: 1; }

.breadcrumbs {
    display: flex;
    align-items: center;
    gap: 8px;
    font-family: var(--mono);
    font-size: 12px;
    color: var(--text-dim);
    margin-bottom: 28px;
    flex-wrap: wrap;
}
.breadcrumbs a {
    color: var(--text-dim);
    text-decoration: none;
    transition: color 0.15s;
}
.breadcrumbs a:hover { color: var(--accent); }
.breadcrumbs span.sep { opacity: 0.45; }
.breadcrumbs span.current { color: var(--text); font-weight: 600; }

.course-hero-grid {
    display: grid;
    grid-template-columns: minmax(0, 1fr) minmax(0, 380px);
    gap: 56px;
    align-items: start;
}
.course-hero-main .tags {
    display: flex;
    gap: 8px;
    margin-bottom: 22px;
    flex-wrap: wrap;
}
.course-hero h1 {
    font-size: clamp(36px, 4.6vw, 56px);
    line-height: 1.04;
    letter-spacing: -0.03em;
    font-weight: 800;
    margin-bottom: 18px;
    color: var(--text);
    text-wrap: balance;
}
.course-hero .subtitle {
    font-size: 22px;
    line-height: 1.35;
    color: var(--text-secondary);
    letter-spacing: -0.01em;
    margin-bottom: 0;
    text-wrap: pretty;
    max-width: 640px;
}

/* Hero side card with meta + CTA */
.hero-side-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--r-xl);
    padding: 26px 26px 22px;
    box-shadow: var(--shadow-1);
    position: sticky;
    top: 96px;
}
.hsc-meta {
    display: flex;
    flex-direction: column;
    gap: 14px;
    margin-bottom: 22px;
    padding-bottom: 22px;
    border-bottom: 1px solid var(--border);
}
.hsc-meta-row {
    display: grid;
    grid-template-columns: 20px 1fr auto;
    gap: 12px;
    align-items: center;
    font-size: 14px;
}
.hsc-meta-row svg { width: 18px; height: 18px; color: var(--text-dim); }
.hsc-meta-row .k { color: var(--text-dim); }
.hsc-meta-row .v { color: var(--text); font-weight: 600; text-align: right; font-variant-numeric: tabular-nums; }
.hsc-price {
    display: flex;
    align-items: baseline;
    gap: 6px;
    margin-bottom: 8px;
}
.hsc-price .from {
    font-size: 12px;
    color: var(--text-dim);
    text-transform: uppercase;
    font-family: var(--mono);
    letter-spacing: 0.06em;
}
.hsc-price b {
    font-size: 30px;
    font-weight: 800;
    letter-spacing: -0.02em;
    color: var(--text);
    font-variant-numeric: tabular-nums;
}
.hsc-price span {
    font-size: 13px;
    color: var(--text-dim);
}
.hsc-actions {
    display: flex;
    flex-direction: column;
    gap: 10px;
    margin-bottom: 10px;
}
.hsc-actions .btn { width: 100%; }
.hsc-legal {
    font-size: 12px;
    color: var(--text-dim);
    text-align: center;
    line-height: 1.5;
    margin-top: 6px;
}

/* ---- Long-form layout ---- */
.course-body {
    padding: 56px 0 96px;
}
.cb-grid {
    display: grid;
    grid-template-columns: minmax(0, 220px) minmax(0, 1fr);
    gap: 80px;
    align-items: start;
}

/* sticky TOC */
.toc {
    position: sticky;
    top: 96px;
    font-family: var(--mono);
    font-size: 13px;
}
.toc-label {
    font-size: 11px;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--text-dim);
    margin-bottom: 14px;
    font-weight: 600;
    padding-bottom: 12px;
    border-bottom: 1px solid var(--border);
}
.toc ol {
    list-style: none;
    padding: 0;
    margin: 0;
    counter-reset: toc;
    display: flex;
    flex-direction: column;
    gap: 4px;
}
.toc li {
    counter-increment: toc;
}
.toc a {
    display: grid;
    grid-template-columns: 24px 1fr;
    gap: 10px;
    padding: 8px 10px;
    border-radius: 6px;
    text-decoration: none;
    color: var(--text-secondary);
    font-size: 13px;
    line-height: 1.4;
    transition: background 0.15s, color 0.15s;
    border-left: 2px solid transparent;
}
.toc a::before {
    content: counter(toc, decimal-leading-zero);
    color: var(--text-faint);
    font-size: 11px;
    font-weight: 600;
    padding-top: 1px;
}
.toc a:hover { color: var(--text); background: var(--bg-soft); }
.toc a.is-active {
    color: var(--accent);
    background: var(--brand-soft);
    border-left-color: var(--accent);
}
.toc a.is-active::before { color: var(--accent); }

/* prose */
.prose { max-width: 720px; }
.prose .intro {
    font-size: 19px;
    line-height: 1.55;
    color: var(--text);
    margin-bottom: 28px;
    font-weight: 400;
    letter-spacing: -0.005em;
}
.prose .intro:first-letter {
    initial-letter: 2.5;
    -webkit-initial-letter: 2.5;
    font-weight: 800;
    color: var(--accent);
    margin-right: 8px;
    padding-right: 4px;
}
.prose .intro + .intro {
    font-size: 17px;
    color: var(--text-secondary);
    margin-bottom: 24px;
}
.prose .intro + .intro:first-letter {
    initial-letter: 1;
    -webkit-initial-letter: 1;
    font-weight: inherit;
    color: inherit;
    margin-right: 0;
    padding-right: 0;
}

.prose h2 {
    font-size: 28px;
    line-height: 1.15;
    letter-spacing: -0.02em;
    font-weight: 800;
    color: var(--text);
    margin-top: 64px;
    margin-bottom: 4px;
    scroll-margin-top: 96px;
    position: relative;
}
.prose h2 .h-num {
    display: block;
    font-family: var(--mono);
    font-size: 11px;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--accent);
    font-weight: 600;
    margin-bottom: 10px;
}
.prose h2:first-of-type { margin-top: 16px; }
.prose p {
    font-size: 17px;
    line-height: 1.65;
    color: var(--text);
    margin-top: 18px;
    text-wrap: pretty;
}
.prose p strong { color: var(--text); font-weight: 700; }

/* inline CTA card inside prose */
.inline-cta {
    margin: 56px 0;
    padding: 32px 32px;
    background:
        radial-gradient(60% 80% at 100% 0%, rgba(199,195,240,0.4), transparent 70%),
        var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--r-xl);
    box-shadow: var(--shadow-1);
}
.inline-cta h3 {
    font-size: 22px;
    font-weight: 800;
    letter-spacing: -0.02em;
    margin-bottom: 8px;
}
.inline-cta p {
    font-size: 15px;
    color: var(--text-secondary);
    margin: 0 0 18px;
}
.inline-cta .row {
    display: flex;
    gap: 12px;
    flex-wrap: wrap;
}

/* related courses */
.related {
    border-top: 1px solid var(--border);
    padding: 72px 0 0;
}
.related-head {
    display: flex;
    align-items: flex-end;
    justify-content: space-between;
    margin-bottom: 28px;
    gap: 24px;
    flex-wrap: wrap;
}
.related-head .h-section { margin: 0; }
.related-head p { color: var(--text-secondary); max-width: 480px; margin: 6px 0 0; }
.related-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 18px;
}
.rel-card {
    display: flex;
    flex-direction: column;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--r-lg);
    padding: 24px 24px 22px;
    text-decoration: none;
    color: inherit;
    transition: transform 0.15s, box-shadow 0.15s, border-color 0.15s;
    box-shadow: var(--shadow-1);
}
.rel-card:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow);
    border-color: var(--border-strong);
}
.rel-card .rel-fam {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    font-family: var(--mono);
    font-size: 11px;
    font-weight: 700;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    color: var(--text-dim);
    margin-bottom: 16px;
}
.rel-card .rel-fam .badge {
    width: 24px; height: 24px;
    border-radius: 6px;
    display: grid;
    place-items: center;
    color: #fff;
    font-family: var(--mono);
    font-size: 11px;
    font-weight: 800;
}
.rel-card[data-fam="python"] .badge { background: linear-gradient(135deg, #3776ab 0%, #4b8bbe 100%); }
.rel-card[data-fam="cpp"] .badge { background: linear-gradient(135deg, #00599c 0%, #044f88 100%); }
.rel-card[data-fam="info"] .badge { background: linear-gradient(135deg, #8a5fd1 0%, #6346b0 100%); }
.rel-card h4 {
    font-size: 19px;
    font-weight: 700;
    letter-spacing: -0.015em;
    line-height: 1.25;
    margin-bottom: 8px;
}
.rel-card p {
    font-size: 13.5px;
    color: var(--text-secondary);
    line-height: 1.5;
    margin-bottom: 18px;
    flex: 1;
}
.rel-card .more {
    font-family: var(--mono);
    font-size: 12px;
    font-weight: 600;
    color: var(--accent);
    display: inline-flex;
    align-items: center;
    gap: 6px;
}
.rel-card .more::after {
    content: '→';
    transition: transform 0.15s;
}
.rel-card:hover .more::after { transform: translateX(3px); }

/* Family-specific accent tints for hero */
.course-hero.fam-python { --course-tint: rgba(82, 113, 255, 0.18); }
.course-hero.fam-cpp    { --course-tint: rgba(255, 130, 99, 0.22); }
.course-hero.fam-info   { --course-tint: rgba(138, 95, 209, 0.20); }

/* Course-level visual mark in hero (the big Py / C++ / И square) */
.course-glyph {
    width: 72px;
    height: 72px;
    border-radius: 18px;
    display: grid;
    place-items: center;
    color: #fff;
    font-family: var(--mono);
    font-size: 28px;
    font-weight: 800;
    letter-spacing: -0.02em;
    margin-bottom: 24px;
    box-shadow: 0 14px 30px -10px rgba(40,30,90,0.25);
}
.fam-python .course-glyph { background: linear-gradient(135deg, #3776ab 0%, #4b8bbe 100%); }
.fam-cpp .course-glyph    { background: linear-gradient(135deg, #00599c 0%, #044f88 100%); }
.fam-info .course-glyph   { background: linear-gradient(135deg, #8a5fd1 0%, #6346b0 100%); }

/* responsive */
@media (max-width: 1080px) {
    .cb-grid { grid-template-columns: 1fr; gap: 32px; }
    .toc {
        position: static;
        font-size: 13px;
    }
    .toc ol {
        flex-direction: row;
        flex-wrap: wrap;
        gap: 6px;
    }
    .toc a { padding: 6px 12px; border-left: none; }
    .toc a.is-active { border-left: none; }
    .related-grid { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 900px) {
    .course-hero-grid { grid-template-columns: 1fr; gap: 36px; }
    .hero-side-card { position: static; max-width: 480px; }
}
@media (max-width: 700px) {
    .related-grid { grid-template-columns: 1fr; }
    .prose h2 { font-size: 24px; margin-top: 48px; }
    .prose .intro { font-size: 17px; }
    .prose p { font-size: 16px; }
    .course-body { padding: 40px 0 64px; }
}