/* ============================================
   DETAIL PAGE - IMMERSIVE HERO VARIANT
   ============================================
   Based on Mockup C: Immersive Hero
   Design Direction: Boldness & Clarity
   - Full-width warm hero banner with category color accent
   - Stats as floating card over the hero/content boundary
   - Single-column content below
   - Accordion-style sections instead of flat cards
   - Related exercises as a horizontal grid
   ============================================ */

@import url('/design-system/platform-tokens.css');

/* ---- HERO BANNER ---- */
.immersive-hero {
    background: #FAF4ED;
    padding: 32px 32px 56px;
    position: relative;
    overflow: hidden;
}

/* Grid texture overlay */
.immersive-hero::before {
    content: '';
    position: absolute;
    inset: 0;
    background-image:
        linear-gradient(rgba(0, 0, 0, 0.03) 1px, transparent 1px),
        linear-gradient(90deg, rgba(0, 0, 0, 0.03) 1px, transparent 1px);
    background-size: 32px 32px;
    pointer-events: none;
}

/* Soft radial warmth */
.immersive-hero::after {
    content: '';
    position: absolute;
    inset: 0;
    background: radial-gradient(circle at 80% 20%, var(--phase-learn-very-light) 0%, transparent 50%);
    pointer-events: none;
}

.immersive-hero-inner {
    max-width: 1120px;
    margin: 0 auto;
    padding: 0 24px;
    position: relative;
    z-index: 1;
}

/* Breadcrumb */
.immersive-breadcrumb {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 13px;
    color: var(--color-ink-faint);
    margin-bottom: 32px;
}
.immersive-breadcrumb a {
    color: var(--color-ink-muted);
    text-decoration: none;
    transition: color 150ms ease;
}
.immersive-breadcrumb a:hover { color: var(--mainsite-primary); }
.immersive-breadcrumb .icon { font-size: 14px; color: var(--color-ink-faint); }

/* Category Badge */
.immersive-category {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 5px 14px;
    border-radius: 100px;
    font-size: 11px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    margin-bottom: 20px;
}

.immersive-hero h1 {
    font-family: var(--font-heading);
    font-size: 56px;
    font-weight: 700;
    letter-spacing: -0.035em;
    line-height: 1.08;
    color: var(--color-ink);
    margin-bottom: 16px;
}

.immersive-hero-desc {
    font-size: 18px;
    line-height: 1.7;
    color: var(--color-ink-secondary);
    max-width: 75%;
    margin-bottom: 32px;
}

.immersive-hero-actions {
    display: flex;
    gap: 10px;
    align-items: center;
    justify-content: flex-end;
}

.immersive-hero-btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 12px 24px;
    border-radius: var(--radius-md, 8px);
    font-family: inherit;
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    transition: all 150ms ease;
    border: none;
    text-decoration: none;
}
.immersive-hero-btn-primary {
    background: var(--mainsite-primary);
    color: white;
}
.immersive-hero-btn-primary:hover {
    background: var(--mainsite-dark);
    box-shadow: var(--mainsite-shadow);
    transform: translateY(-1px);
}
.immersive-hero-btn-secondary {
    background: var(--bg-surface);
    color: var(--mainsite-primary);
    border: 1px solid var(--phase-learn-light);
}
.immersive-hero-btn-secondary:hover {
    background: var(--mainsite-very-light, #FEF2F2);
    border-color: var(--mainsite-primary);
    color: var(--mainsite-dark);
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.06);
}
.immersive-hero-btn .icon { font-size: 18px; }

/* ---- STATS BAR (floating over hero/content boundary) ---- */
.immersive-stats-float {
    max-width: 1168px;
    margin: -32px auto 0;
    padding: 0 24px;
    position: relative;
    z-index: 2;
}

.immersive-stats-card {
    display: flex;
    gap: 0;
    background: var(--bg-surface);
    border: 1px solid rgba(0, 0, 0, 0.08);
    border-radius: 16px;
    overflow: hidden;
    box-shadow: var(--shadow-lg);
}

.immersive-stats-item {
    flex: 1;
    padding: 20px 24px;
    display: flex;
    align-items: center;
    gap: 14px;
    border-right: 1px solid rgba(0, 0, 0, 0.08);
}
.immersive-stats-item:last-child { border-right: none; }

.immersive-stats-icon {
    width: 44px;
    height: 44px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--mainsite-very-light, #FEF2F2);
    border-radius: var(--radius-md, 8px);
    flex-shrink: 0;
}
.immersive-stats-icon .icon { font-size: 22px; color: var(--mainsite-primary); }

.immersive-stats-label {
    font-size: 11px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    color: var(--color-ink-muted);
    margin-bottom: 2px;
}
.immersive-stats-value {
    font-size: 16px;
    font-weight: 700;
    color: var(--color-ink);
}

/* ---- BUTTON BASE (fallback if components.css is outdated) ---- */
.ws-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    font-family: 'Inter', -apple-system, sans-serif;
    font-weight: 600;
    letter-spacing: 0.025em;
    border: none;
    cursor: pointer;
    text-decoration: none;
    transition: all 150ms ease;
}
.ws-btn--sm { padding: 8px 14px; font-size: 13px; border-radius: 8px; }
.ws-btn--md { padding: 12px 20px; font-size: 14px; border-radius: 10px; }
.ws-btn--icon-only.ws-btn--sm { padding: 8px; }
.ws-btn--icon-only.ws-btn--md { padding: 12px; }
.ws-btn__icon { display: inline-flex; align-items: center; justify-content: center; }
.ws-btn--primary {
    background: var(--mainsite-gradient);
    color: #FFFFFF;
}
.ws-btn--primary:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: var(--mainsite-shadow);
}
.ws-btn--secondary {
    background: #FFFFFF;
    color: var(--color-navy);
    border: 2px solid var(--color-navy);
}
.ws-btn--secondary:hover:not(:disabled) {
    background: var(--color-navy);
    color: #FFFFFF;
}
.ws-btn--ghost {
    background: transparent;
    color: #5C5242;
    border: 1px solid #D6D3D1;
}
.ws-btn--ghost:hover:not(:disabled) {
    background: #FAFAF9;
    border-color: #A8A29E;
}

/* ---- QUICK ACTIONS BAR ---- */
.immersive-quick-actions {
    max-width: 1120px;
    margin: 0 auto;
    padding: 40px 24px 0;
    display: flex;
    gap: 8px;
    align-items: center;
    background: #FFFFFF;
}

.immersive-qa-spacer { flex: 1; }

.immersive-quick-actions .ws-btn--ghost {
    background: #FFFFFF;
}
.immersive-quick-actions .ws-btn--ghost:hover {
    background: var(--mainsite-very-light, #FEF2F2);
    border-color: var(--phase-learn-light);
}
.immersive-quick-actions .ws-btn--ghost:hover .icon {
    color: var(--mainsite-primary);
}
.immersive-quick-actions .ws-btn--ghost.is-favorite,
.immersive-quick-actions .ws-btn--ghost.has-note {
    background: var(--mainsite-very-light, #FEF2F2);
    border-color: var(--phase-learn-light);
    color: var(--mainsite-primary);
}
.immersive-quick-actions .ws-btn--ghost.is-favorite .icon,
.immersive-quick-actions .ws-btn--ghost.has-note .icon {
    color: var(--mainsite-primary);
    fill: var(--mainsite-primary);
}
.immersive-quick-actions .ws-btn--ghost.is-favorite:hover,
.immersive-quick-actions .ws-btn--ghost.has-note:hover {
    background: var(--phase-learn-light);
    border-color: var(--mainsite-primary);
}

.immersive-qa-play {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 8px 18px;
    background: var(--mainsite-very-light, #FEF2F2);
    border: 1px solid var(--phase-learn-very-light);
    border-radius: 100px;
    font-family: inherit;
    font-size: 13px;
    font-weight: 600;
    color: var(--mainsite-primary);
    cursor: pointer;
    text-decoration: none;
    transition: all 150ms ease;
}
.immersive-qa-play:hover {
    background: var(--mainsite-light, #FEE2E2);
    border-color: var(--phase-learn-light);
}
.immersive-qa-play .icon { font-size: 16px; }

/* ---- CONTENT AREA (single column) ---- */
.immersive-content {
    max-width: 1120px;
    margin: 0 auto;
    padding: 40px 24px 80px;
    background: #FFFFFF;
}

/* ---- TABS ---- */
.immersive-tabs {
    display: flex;
    gap: 0;
    margin-bottom: 32px;
}
.immersive-tab {
    padding: 14px 24px;
    font-family: inherit;
    font-size: 16px;
    font-weight: 500;
    color: var(--color-ink-muted);
    background: none;
    border: none;
    border-bottom: 2px solid rgba(0, 0, 0, 0.12);
    cursor: pointer;
    transition: all 150ms ease;
}
.immersive-tab:hover {
    color: var(--color-ink);
}
.immersive-tab.active {
    color: var(--mainsite-primary);
    border-bottom-color: var(--mainsite-primary);
    font-weight: 600;
}

.immersive-tab-panel { display: none; }
.immersive-tab-panel.active { display: block; }

/* ---- ACCORDION SECTIONS ---- */
.immersive-accordion {
    margin-bottom: 16px;
    box-shadow: var(--shadow-md);
    border-radius: 12px;
}

.immersive-accordion-trigger {
    display: flex;
    align-items: center;
    gap: 12px;
    width: 100%;
    padding: 18px 24px;
    background: var(--bg-surface);
    border: 1px solid rgba(0, 0, 0, 0.08);
    border-radius: 12px;
    font-family: var(--font-heading);
    font-size: 17px;
    font-weight: 600;
    letter-spacing: -0.01em;
    color: var(--color-ink);
    cursor: pointer;
    transition: all 150ms ease;
    text-align: left;
}
.immersive-accordion-trigger:hover {
    border-color: rgba(0, 0, 0, 0.12);
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.06);
}
.immersive-accordion-trigger .immersive-section-icon {
    width: 36px;
    height: 36px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--mainsite-very-light, #FEF2F2);
    border-radius: var(--radius-md, 8px);
    flex-shrink: 0;
}
.immersive-accordion-trigger .immersive-section-icon .icon { font-size: 20px; color: var(--mainsite-primary); }

.immersive-accordion-trigger .immersive-chevron {
    margin-left: auto;
    width: 20px;
    height: 20px;
    color: var(--color-ink-faint);
    fill: currentColor;
    flex-shrink: 0;
    transition: transform 200ms ease;
}
.immersive-accordion.open .immersive-accordion-trigger .immersive-chevron {
    transform: rotate(180deg);
}
/* Override global button:hover .icon rotation */
.immersive-accordion-trigger:hover .immersive-chevron {
    transform: rotate(0deg);
}
.immersive-accordion.open .immersive-accordion-trigger:hover .immersive-chevron {
    transform: rotate(180deg);
}

.immersive-accordion.open .immersive-accordion-trigger {
    border-bottom-left-radius: 0;
    border-bottom-right-radius: 0;
    border-bottom-color: transparent;
}

.immersive-accordion-body {
    display: none;
    background: var(--bg-surface);
    border: 1px solid rgba(0, 0, 0, 0.08);
    border-top: none;
    border-radius: 0 0 12px 12px;
    padding: 20px 24px 24px;
}
.immersive-accordion.open .immersive-accordion-body { display: block; }

.immersive-accordion-body p, .immersive-accordion-body li {
    font-size: 15px;
    line-height: 1.7;
    color: var(--color-ink-secondary);
}
.immersive-accordion-body p { margin-bottom: 14px; }
.immersive-accordion-body p:last-child { margin-bottom: 0; }
.immersive-accordion-body ul, .immersive-accordion-body ol {
    padding-left: 20px;
    margin: 0;
}
.immersive-accordion-body li { margin-bottom: 6px; }

.immersive-accordion-body h3 {
    font-family: var(--font-heading);
    font-size: 18px;
    font-weight: 600;
    color: var(--color-ink);
    margin: 20px 0 10px;
    letter-spacing: -0.01em;
}
.immersive-accordion-body h3:first-child { margin-top: 0; }

/* When to use - inline split */
.immersive-use-split {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
}

.immersive-use-box {
    padding: 20px;
    border-radius: var(--radius-md, 8px);
}
.immersive-use-box.yes {
    background: rgba(22, 163, 74, 0.05);
    border: 1px solid rgba(22, 163, 74, 0.15);
}
.immersive-use-box.no {
    background: rgba(220, 38, 38, 0.05);
    border: 1px solid rgba(220, 38, 38, 0.12);
}

.immersive-use-label {
    display: flex;
    align-items: center;
    gap: 6px;
    font-size: 13px;
    font-weight: 600;
    margin-bottom: 12px;
}
.immersive-use-label .icon { font-size: 18px; }
.immersive-use-box.yes .immersive-use-label { color: #16a34a; }
.immersive-use-box.no .immersive-use-label { color: #dc2626; }

.immersive-use-box ul {
    list-style: none;
    padding: 0;
}
.immersive-use-box li {
    font-size: 14px;
    line-height: 1.6;
    color: var(--color-ink-secondary);
    padding: 5px 0;
}
.immersive-use-box li + li {
    border-top: 1px solid rgba(0, 0, 0, 0.08);
}

/* ---- COMMENTS/DISCUSSION (inside immersive content) ---- */
.immersive-content .comments-section {
    background: #FFFFFF;
    border: none;
}
.immersive-content .comments-section .detail-section-title .icon {
    filter: brightness(0) saturate(100%) invert(38%) sepia(72%) saturate(1637%) hue-rotate(332deg) brightness(93%) contrast(87%);
}
.immersive-content .comments-count {
    color: var(--mainsite-primary, #E54D4D);
    background: var(--mainsite-very-light, #FEF2F2);
}

/* ---- RELATED EXERCISES STRIP ---- */
.immersive-related-section {
    padding: 48px 24px 80px;
    background: #FFFFFF;
}

.immersive-related-inner {
    max-width: 1120px;
    margin: 0 auto;
}

.immersive-related-title {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 16px;
}
.immersive-related-title h2 {
    font-family: var(--font-heading);
    font-size: 22px;
    font-weight: 600;
    color: var(--color-ink);
    letter-spacing: -0.01em;
}
.immersive-related-title a {
    font-size: 13px;
    color: var(--mainsite-primary);
    text-decoration: none;
    font-weight: 500;
}

.immersive-related-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 16px;
}

.immersive-related-card {
    background: #FAF4ED;
    border: 1px solid rgba(0, 0, 0, 0.06);
    border-radius: 12px;
    padding: 20px;
    text-decoration: none;
    transition: all 150ms ease;
}
.immersive-related-card:hover {
    border-color: var(--mainsite-primary);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
    transform: translateY(-2px);
}

.immersive-related-card-icon {
    width: 44px;
    height: 44px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--mainsite-very-light, #FEF2F2);
    border-radius: var(--radius-md, 8px);
    margin-bottom: 14px;
}
.immersive-related-card-icon .icon { font-size: 22px; color: var(--mainsite-primary); }

.immersive-related-card h4 {
    font-family: var(--font-heading);
    font-size: 17px;
    font-weight: 600;
    color: var(--color-ink);
    margin-bottom: 4px;
    letter-spacing: -0.01em;
}
.immersive-related-card p {
    font-size: 13px;
    color: var(--color-ink-muted);
}

/* ---- RESPONSIVE ---- */
@media (max-width: 768px) {
    .immersive-hero { padding: 24px 16px 48px; }
    .immersive-hero-inner { padding: 0 8px; }
    .immersive-hero h1 { font-size: 36px; }
    .immersive-hero-desc { font-size: 16px; }

    .immersive-stats-card {
        flex-direction: column;
        border-radius: 12px;
    }
    .immersive-stats-item {
        border-right: none;
        border-bottom: 1px solid rgba(0, 0, 0, 0.08);
        padding: 14px 20px;
    }
    .immersive-stats-item:last-child { border-bottom: none; }

    .immersive-quick-actions { padding: 24px 24px 0; }
    .immersive-content { padding: 0 24px 60px; }

    .immersive-tabs { overflow-x: auto; }
    .immersive-tab { padding: 12px 16px; font-size: 14px; white-space: nowrap; }

    .immersive-accordion-trigger { padding: 14px 18px; font-size: 15px; }
    .immersive-accordion-body { padding: 16px 18px 20px; }

    .immersive-use-split { grid-template-columns: 1fr; }

    .immersive-related-section { padding: 32px 16px 60px; }
    .immersive-related-grid { grid-template-columns: 1fr; }
}

@media (max-width: 480px) {
    .immersive-hero h1 { font-size: 28px; }
    .immersive-hero-actions { flex-direction: column; align-items: stretch; }
}