:root {
    --course-bg: #f3eee4;
    --course-surface: rgba(255, 255, 255, 0.92);
    --course-ink: #171f28;
    --course-ink-soft: #4e5a66;
    --course-accent: #164f59;
    --course-accent-warm: #9a4c13;
    --course-gold: #c2a052;
    --course-border: rgba(23, 31, 40, 0.14);
    --course-shadow: 0 18px 42px rgba(23, 31, 40, 0.1);
    --course-radius-xl: 8px;
    --course-radius-lg: 8px;
    --course-radius-md: 8px;
    --course-sans: "Google Sans", "Helvetica Neue", Arial, sans-serif;
    --course-serif: "Google Sans", "Helvetica Neue", Arial, sans-serif;
}

* {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body.course-page {
    margin: 0;
    min-height: 100vh;
    color: var(--course-ink);
    font-family: var(--course-serif);
    font-size: 18px;
    background:
        radial-gradient(circle at 12% 0%, rgba(194, 160, 82, 0.08), transparent 28%),
        radial-gradient(circle at 88% 8%, rgba(22, 79, 89, 0.08), transparent 30%),
        #f4f6f8;
    text-rendering: optimizeLegibility;
    -webkit-font-smoothing: antialiased;
}

a {
    color: var(--course-accent);
    text-underline-offset: 0.18em;
}

a:hover {
    color: var(--course-accent-warm);
}

.course-shell {
    width: min(1160px, calc(100% - 32px));
    margin: 0 auto;
    padding: 28px 0 48px;
}

.course-shell--narrow {
    width: min(980px, calc(100% - 32px));
}

.course-back {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    margin-bottom: 18px;
    color: var(--course-ink-soft);
    text-decoration: none;
    font-family: var(--course-sans);
    font-size: 0.92rem;
    font-weight: 600;
}

.course-back:hover {
    color: var(--course-ink);
}

.course-hero {
    position: relative;
    display: grid;
    gap: 28px;
    padding: 42px;
    border: 1px solid var(--course-border);
    border-radius: var(--course-radius-xl);
    background: linear-gradient(135deg, rgba(255, 255, 255, 0.98), rgba(250, 246, 237, 0.94));
    box-shadow: var(--course-shadow);
    overflow: hidden;
}

.course-hero::before {
    content: "";
    position: absolute;
    inset: 0 0 auto;
    height: 5px;
    background: linear-gradient(90deg, var(--course-accent), var(--course-gold), var(--course-accent-warm));
}

.course-hero-top {
    display: grid;
    grid-template-columns: minmax(0, 1fr) minmax(220px, 280px);
    gap: 28px;
    align-items: center;
}

.course-hero-meta-full {
    grid-column: 1 / -1;
}

.course-hero-media {
    display: flex;
    justify-content: flex-end;
}

.course-hero-image {
    width: min(100%, 280px);
    aspect-ratio: 1;
    object-fit: contain;
    border-radius: 50%;
    background: transparent;
}

.course-kicker {
    margin: 0 0 10px;
    color: var(--course-accent-warm);
    font-family: var(--course-sans);
    font-size: 0.78rem;
    font-weight: 600;
    letter-spacing: 0.08em;
    text-transform: uppercase;
}

.course-title {
    margin: 0;
    max-width: 13.5ch;
    font-size: clamp(2rem, 4vw, 3.2rem);
    font-weight: 400;
    line-height: 0.98;
}

.course-summary {
    max-width: 70ch;
    margin: 22px 0 0;
    color: var(--course-ink-soft);
    font-size: 1.22rem;
    line-height: 1.65;
}

.course-meta-grid {
    display: grid;
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 14px;
    margin-top: 24px;
}

.course-meta-item {
    padding: 18px;
    border: 1px solid rgba(13, 92, 99, 0.12);
    border-radius: var(--course-radius-md);
    background: rgba(255, 255, 255, 0.68);
    box-shadow: 0 1px 0 rgba(255, 255, 255, 0.8) inset;
}

.course-meta-label {
    display: block;
    margin-bottom: 6px;
    color: var(--course-ink-soft);
    font-family: var(--course-sans);
    font-size: 0.72rem;
    font-weight: 600;
    letter-spacing: 0.06em;
    text-transform: uppercase;
}

.course-meta-value {
    display: block;
    font-size: 1.06rem;
    font-weight: 500;
    line-height: 1.45;
}

.course-section {
    margin-top: 28px;
}

.course-section-title {
    margin: 0 0 14px;
    color: var(--course-ink);
    font-size: 1.72rem;
    font-weight: 600;
}

.course-grid {
    display: grid;
    grid-template-columns: minmax(0, 1.2fr) minmax(320px, 0.8fr);
    gap: 22px;
    align-items: start;
}

.course-card {
    padding: 24px;
    border: 1px solid var(--course-border);
    border-radius: 20px;
    background: var(--course-surface);
    box-shadow: 0 16px 40px rgba(29, 45, 59, 0.08);
}

.course-feature {
    display: grid;
    grid-template-columns: minmax(0, 1.1fr) minmax(300px, 0.9fr);
    gap: 22px;
    align-items: center;
}

.course-card--tinted {
    background: linear-gradient(180deg, rgba(255, 249, 232, 0.95), rgba(255, 255, 255, 0.92));
}

.course-card--dark {
    color: #eef6f6;
    background: linear-gradient(145deg, #16353a, #0e2428);
}

.course-card--dark a {
    color: #91e4dc;
}

.course-card p:first-child,
.course-card ul:first-child {
    margin-top: 0;
}

.course-card p:last-child,
.course-card ul:last-child {
    margin-bottom: 0;
}

.course-prose {
    color: var(--course-ink-soft);
    font-size: 1.14rem;
    line-height: 1.82;
}

.course-prose strong,
.course-prose b {
    color: var(--course-ink);
}

.course-prose em,
.course-prose i {
    color: #6a4e1f;
}

.course-prose--spaced {
    margin-top: 16px;
}

.course-chip-list {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
}

.course-chip {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 10px 14px;
    border: 1px solid rgba(13, 92, 99, 0.16);
    border-radius: 6px;
    background: rgba(255, 255, 255, 0.86);
    color: var(--course-ink);
    text-decoration: none;
    font-family: var(--course-sans);
    font-size: 0.95rem;
    font-weight: 600;
}

.course-chip:hover {
    border-color: rgba(13, 92, 99, 0.28);
}

.course-media,
.course-image-grid {
    display: grid;
    gap: 14px;
}

.course-image-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
}

.course-media-caption {
    margin: 0;
    color: var(--course-ink-soft);
    font-size: 1rem;
    line-height: 1.62;
}

.course-embed {
    width: 100%;
    aspect-ratio: 16 / 9;
    border: 0;
    border-radius: var(--course-radius-lg);
    box-shadow: 0 8px 22px rgba(17, 32, 46, 0.1);
}

.course-image {
    display: block;
    width: 100%;
    height: auto;
    border-radius: var(--course-radius-lg);
    box-shadow: 0 8px 22px rgba(17, 32, 46, 0.1);
}

.course-list {
    margin: 0;
    padding-left: 20px;
    color: var(--course-ink-soft);
    line-height: 1.72;
}

.course-list li + li {
    margin-top: 10px;
}

.course-timeline {
    margin: 8px 0 0;
}

.course-timeline-axis {
    display: grid;
    gap: 18px;
}

.course-timeline-item {
    margin: 0;
}

.course-panel {
    position: relative;
    margin: 0;
    border: 1px solid rgba(17, 36, 52, 0.1);
    border-radius: 18px;
    background: rgba(255, 255, 255, 0.95);
    box-shadow: 0 12px 24px rgba(17, 32, 46, 0.06);
    overflow: hidden;
}

.course-panel::before {
    content: "";
    position: absolute;
    inset: 18px auto 18px 18px;
    width: 3px;
    border-radius: 999px;
    background: linear-gradient(180deg, rgba(13, 92, 99, 0.9), rgba(13, 92, 99, 0.16));
}

.course-panel::after {
    content: "";
    position: absolute;
    top: 32px;
    left: 13px;
    width: 13px;
    height: 13px;
    border: 2px solid #fff;
    border-radius: 50%;
    background: var(--course-accent);
    box-shadow: 0 0 0 1px rgba(13, 92, 99, 0.24);
}

.course-panel-summary {
    display: grid;
    gap: 10px;
    margin: 0;
    padding: 18px 20px 18px 40px;
    cursor: pointer;
    list-style: none;
}

.course-panel-summary::-webkit-details-marker {
    display: none;
}

.course-panel-topline {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 10px 12px;
}

.course-panel-range {
    color: var(--course-accent);
    font-family: var(--course-sans);
    font-size: 0.9rem;
    font-weight: 800;
    letter-spacing: 0.04em;
    text-transform: uppercase;
}

.course-panel-title-row {
    display: flex;
    flex-wrap: wrap;
    align-items: baseline;
    justify-content: space-between;
    gap: 10px 18px;
}

.course-panel-title {
    color: #314252;
    font-size: 1.18rem;
    font-weight: 650;
    letter-spacing: -0.01em;
}

.course-panel-hint {
    color: var(--course-ink-soft);
    font-family: var(--course-sans);
    font-size: 0.9rem;
    font-weight: 700;
}

.course-panel-content {
    padding: 0 20px 20px 40px;
    border-top: 1px solid rgba(17, 36, 52, 0.08);
}

.course-subtopic {
    margin: 18px 0 8px;
    color: var(--course-accent-warm);
    font-size: 0.96rem;
    font-weight: 500;
}

.course-lecture-list {
    position: relative;
    margin: 0;
    padding: 0 0 0 26px;
    color: var(--course-ink-soft);
    line-height: 1.72;
    list-style: none;
}

.course-lecture-list::before {
    content: "";
    position: absolute;
    top: 4px;
    bottom: 4px;
    left: 7px;
    width: 2px;
    border-radius: 6px;
    background: linear-gradient(180deg, rgba(13, 92, 99, 0.28), rgba(13, 92, 99, 0.12));
}

.course-lecture-list li {
    position: relative;
    margin: 0;
    padding: 0 0 0 14px;
    color: var(--course-ink-soft);
    line-height: 1.72;
}

.course-lecture-list li::before {
    content: "";
    position: absolute;
    top: 0.52em;
    left: -22px;
    width: 10px;
    height: 10px;
    border: 2px solid var(--course-accent);
    border-radius: 50%;
    background: #fff;
    box-shadow: 0 0 0 3px rgba(13, 92, 99, 0.08);
}

.course-lecture-list li + li {
    margin-top: 10px;
}

.course-lecture-list li strong {
    color: var(--course-ink);
    font-weight: 600;
}

.course-panel-callout {
    margin-top: 16px;
}

@media (max-width: 960px) {
    .course-meta-grid,
    .course-grid,
    .course-image-grid,
    .course-feature,
    .course-hero-top {
        grid-template-columns: 1fr;
    }

    .course-shell {
        width: min(100% - 24px, 1160px);
    }

    .course-shell--narrow {
        width: min(100% - 24px, 980px);
    }

    .course-hero,
    .course-card {
        padding: 22px;
    }

    .course-hero-media {
        justify-content: flex-start;
    }

    .course-hero-image {
        width: min(100%, 240px);
    }
}

@media (max-width: 640px) {
    .course-shell {
        padding-top: 18px;
        padding-bottom: 32px;
    }

    .course-hero {
        padding: 22px 18px;
    }

    .course-title {
        max-width: none;
        font-size: 2rem;
    }

    .course-card {
        padding: 18px;
    }
}