:root {
  --oc-bg: var(--theme-bg, #f5f7fb);
  --oc-surface: var(--theme-surface, #fff);
  --oc-raised: var(--theme-surface-raised, #fff);
  --oc-muted-surface: var(--theme-surface-muted, #eef2f7);
  --oc-heading: var(--theme-heading, #15295d);
  --oc-ink: var(--theme-text, #172033);
  --oc-muted: var(--theme-text-muted, #5f6c81);
  --oc-line: var(--theme-border, #dce3ee);
  --oc-blue: #235fc5;
  --oc-blue-strong: #184b9d;
  --oc-blue-soft: #eaf1ff;
  --oc-orange: #e66a19;
  --oc-green: #147a4a;
  --oc-green-soft: #e9f8f0;
  --oc-amber: #9a5b00;
  --oc-amber-soft: #fff5df;
  --oc-focus: var(--theme-focus, #f59e0b);
  --oc-shadow: 0 12px 30px rgba(27, 43, 78, .08);
}

* { box-sizing: border-box; }
.online-course-page { min-height: 100vh; margin: 0; background: var(--oc-bg); color: var(--oc-ink); font-family: 'Roboto', system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif; }
.oc-header { position: sticky; top: 0; z-index: 30; background: var(--theme-header, rgba(255,255,255,.95)); border-bottom: 1px solid var(--oc-line); backdrop-filter: blur(16px); }
.oc-header-inner { width: min(1240px, calc(100% - 40px)); min-height: 72px; margin: 0 auto; display: flex; align-items: center; justify-content: space-between; gap: 20px; }
.oc-brand { display: inline-flex; align-items: center; gap: 11px; color: var(--oc-heading); text-decoration: none; font-size: 1.18rem; font-weight: 800; letter-spacing: -.03em; }
.oc-brand img { width: 38px; height: 38px; object-fit: contain; }
.oc-brand-word span { color: var(--oc-orange); }
.oc-nav { display: flex; align-items: center; gap: 22px; }
.oc-nav a, .oc-nav button { border: 0; background: none; color: var(--oc-heading); cursor: pointer; font: inherit; font-weight: 700; text-decoration: none; }
.oc-nav a:hover, .oc-nav button:hover { color: var(--oc-blue); }
.oc-shell { width: min(1240px, calc(100% - 40px)); margin: 36px auto 72px; }

.oc-eyebrow { margin: 0 0 8px; color: var(--oc-blue); font-size: .76rem; font-weight: 800; letter-spacing: .105em; text-transform: uppercase; }
.oc-title { margin: 0 0 12px; color: var(--oc-heading); font-size: clamp(2rem, 4vw, 3rem); line-height: 1.08; letter-spacing: -.035em; }
.oc-subtitle { max-width: 780px; margin: 0; color: var(--oc-muted); font-size: 1rem; line-height: 1.65; }
.oc-card, .oc-course-card { background: var(--oc-surface); border: 1px solid var(--oc-line); border-radius: 18px; box-shadow: var(--oc-shadow); }
.oc-card { padding: 26px; }
.oc-course-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(310px, 1fr)); gap: 20px; margin-top: 30px; }
.oc-course-card { display: flex; flex-direction: column; align-items: flex-start; gap: 14px; padding: 26px; }
.oc-course-card h2 { margin: 0; color: var(--oc-heading); font-size: 1.35rem; }
.oc-course-card p { margin: 0; color: var(--oc-muted); line-height: 1.55; }
.oc-card-stats { display: flex; flex-wrap: wrap; gap: 18px; width: 100%; padding: 14px 0; border-top: 1px solid var(--oc-line); color: var(--oc-muted); font-size: .88rem; }
.oc-card-stats strong { color: var(--oc-heading); }
.oc-pill { display: inline-flex; align-items: center; width: fit-content; padding: 5px 10px; border-radius: 999px; background: var(--oc-blue-soft); color: var(--oc-blue); font-size: .73rem; font-weight: 800; }
.oc-pill.ready { background: var(--oc-green-soft); color: var(--oc-green); }
.oc-pill.pending { background: var(--oc-amber-soft); color: var(--oc-amber); }
.oc-button, .oc-outline-action { display: inline-flex; min-height: 42px; align-items: center; justify-content: center; padding: 0 17px; border: 1px solid var(--oc-blue); border-radius: 9px; background: var(--oc-blue); color: #fff; cursor: pointer; font: inherit; font-weight: 750; text-decoration: none; transition: transform .16s ease, background .16s ease, border-color .16s ease; }
.oc-button:hover:not(:disabled), .oc-outline-action:hover:not(:disabled) { background: var(--oc-blue-strong); border-color: var(--oc-blue-strong); transform: translateY(-1px); }
.oc-button.secondary { background: var(--oc-surface); color: var(--oc-blue); }
.oc-button:disabled, .oc-outline-action:disabled { border-color: var(--oc-line); background: var(--oc-muted-surface); color: var(--oc-muted); cursor: not-allowed; transform: none; }
.oc-text-button { padding: 5px 0; border: 0; background: none; color: var(--oc-blue); cursor: pointer; font: inherit; font-weight: 750; }
.oc-text-button:hover { text-decoration: underline; }
.oc-notice { display: block; margin: 20px 0 26px; padding: 16px 18px; border: 1px solid; border-radius: 12px; line-height: 1.55; }
.oc-notice.warning { border-color: #ecc778; background: var(--oc-amber-soft); color: #714200; }
.oc-notice.info { border-color: #b9d2f5; background: var(--oc-blue-soft); color: #164a8c; }
.oc-resource-link, .oc-notice a { color: inherit; font-weight: 750; }
.oc-empty { padding: 60px 24px; text-align: center; }
.oc-auth-redirect { max-width: 760px; margin: 45px auto 0; }
.oc-auth-redirect .oc-button { margin-top: 16px; }

/* Course outline */
.oc-overview-header { display: flex; align-items: flex-end; justify-content: space-between; gap: 30px; margin: 28px 0; }
.oc-overall-progress { display: grid; min-width: 142px; min-height: 86px; place-content: center; border: 1px solid var(--oc-line); border-radius: 16px; background: var(--oc-surface); text-align: center; box-shadow: var(--oc-shadow); }
.oc-overall-progress strong { color: var(--oc-heading); font-size: 1.7rem; line-height: 1; }
.oc-overall-progress span { margin-top: 5px; color: var(--oc-muted); font-size: .75rem; font-weight: 700; text-transform: uppercase; letter-spacing: .06em; }
.oc-overview-grid { display: grid; grid-template-columns: minmax(0, 1.65fr) minmax(280px, .75fr); gap: 22px; align-items: start; }
.oc-outline { padding: 0; overflow: hidden; }
.oc-section-heading { display: flex; align-items: center; justify-content: space-between; gap: 18px; padding: 24px 26px 20px; border-bottom: 1px solid var(--oc-line); }
.oc-section-heading h2, .oc-progress-card h2 { margin: 0; color: var(--oc-heading); font-size: 1.35rem; }
.oc-section-heading > span { color: var(--oc-muted); font-size: .85rem; font-weight: 700; }
.oc-outline-row { display: grid; grid-template-columns: 44px minmax(0, 1fr) 100px 116px; gap: 14px; align-items: center; min-height: 78px; padding: 12px 22px; border-bottom: 1px solid var(--oc-line); }
.oc-outline-row:last-child { border-bottom: 0; }
.oc-outline-row:nth-child(odd) { background: color-mix(in srgb, var(--oc-muted-surface) 55%, transparent); }
.oc-outline-row.is-locked { opacity: .72; }
.oc-outline-number { display: grid; min-width: 34px; height: 34px; place-items: center; border-radius: 10px; background: var(--oc-muted-surface); color: var(--oc-heading); font-size: .78rem; font-weight: 800; }
.oc-outline-row.is-complete .oc-outline-number { background: var(--oc-green-soft); color: var(--oc-green); }
.oc-outline-copy { min-width: 0; }
.oc-outline-copy strong { display: block; color: var(--oc-heading); line-height: 1.35; }
.oc-outline-copy small { display: block; margin-top: 4px; color: var(--oc-muted); line-height: 1.35; }
.oc-outline-status { color: var(--oc-muted); font-size: .82rem; font-weight: 750; }
.oc-outline-row.is-complete .oc-outline-status { color: var(--oc-green); }
.oc-outline-action { min-height: 38px; padding: 0 12px; font-size: .82rem; }
.oc-progress-card { position: sticky; top: 96px; }
.oc-progress-card dl { margin: 22px 0 18px; }
.oc-progress-card dl div { display: flex; justify-content: space-between; gap: 16px; padding: 12px 0; border-bottom: 1px solid var(--oc-line); }
.oc-progress-card dt { color: var(--oc-muted); }
.oc-progress-card dd { margin: 0; color: var(--oc-heading); font-weight: 800; text-align: right; }
.oc-progress-bar, .oc-player-progress { overflow: hidden; height: 8px; border-radius: 999px; background: var(--oc-muted-surface); }
.oc-progress-bar span, .oc-player-progress span { display: block; height: 100%; border-radius: inherit; background: linear-gradient(90deg, var(--oc-blue), #4e84df); }
.oc-progress-note { margin: 16px 0 0; color: var(--oc-muted); font-size: .9rem; line-height: 1.55; }

/* Page player */
.oc-player-shell { width: min(1160px, 100%); margin: 0 auto; }
.oc-player-topbar { display: grid; grid-template-columns: 1fr auto 1fr; align-items: center; gap: 20px; margin-bottom: 15px; }
.oc-player-course { display: flex; align-items: baseline; justify-content: center; gap: 10px; color: var(--oc-heading); }
.oc-player-course span, .oc-page-count { color: var(--oc-muted); font-size: .85rem; }
.oc-page-count { justify-self: end; font-weight: 700; }
.oc-player-progress { height: 6px; margin-bottom: 18px; }
.oc-player-card { display: grid; grid-template-columns: minmax(340px, .85fr) minmax(0, 1.15fr); min-height: 540px; padding: 0; overflow: hidden; }
.oc-player-visual { position: relative; min-height: 100%; background: var(--oc-muted-surface); }
.oc-player-visual img { width: 100%; height: 100%; min-height: 540px; object-fit: cover; display: block; }
.oc-image-caption { position: absolute; inset: auto 18px 18px; display: flex; flex-direction: column; gap: 3px; padding: 13px 15px; border: 1px solid rgba(255,255,255,.34); border-radius: 11px; background: rgba(9, 22, 45, .82); color: #fff; backdrop-filter: blur(8px); }
.oc-image-caption span { font-size: .72rem; font-weight: 800; text-transform: uppercase; letter-spacing: .08em; }
.oc-image-caption strong { font-size: .95rem; }
.oc-player-content { padding: clamp(28px, 4vw, 52px); }
.oc-player-content h1 { max-width: 700px; margin: 0 0 7px; color: var(--oc-heading); font-size: clamp(2rem, 4vw, 3.15rem); line-height: 1.04; letter-spacing: -.04em; }
.oc-page-position { margin: 0 0 20px; color: var(--oc-muted); font-size: .84rem; font-weight: 700; }
.oc-narration { display: grid; gap: 10px; margin: 0 0 25px; padding: 13px 14px; border: 1px solid var(--oc-line); border-radius: 12px; background: var(--oc-muted-surface); }
.oc-audio-heading { display: flex; align-items: center; justify-content: space-between; gap: 14px; }
.oc-audio-heading span { color: var(--oc-heading); font-size: .76rem; font-weight: 800; letter-spacing: .065em; text-transform: uppercase; }
.oc-audio-heading strong { color: var(--oc-muted); font-size: .75rem; font-weight: 750; }
.oc-audio-controls { display: grid; grid-template-columns: auto minmax(0, 1fr); align-items: center; gap: 12px; }
.oc-audio-toggle { display: inline-flex; align-items: center; justify-content: center; flex: none; width: 32px; height: 32px; padding: 0; border: 1px solid var(--oc-blue); border-radius: 50%; background: var(--oc-blue); color: #fff; cursor: pointer; }
.oc-audio-toggle svg { width: 16px; height: 16px; fill: currentColor; }
.oc-audio-toggle:hover:not(:disabled) { background: var(--oc-blue-strong); border-color: var(--oc-blue-strong); }
.oc-audio-toggle:disabled { opacity: .48; cursor: not-allowed; }
.oc-audio-timeline { display: grid; min-width: 0; gap: 3px; }
.oc-audio-timeline input[type="range"] { --oc-audio-progress: 0%; width: 100%; height: 20px; margin: 0; appearance: none; background: transparent; cursor: pointer; }
.oc-audio-timeline input[type="range"]::-webkit-slider-runnable-track { height: 6px; border-radius: 999px; background: linear-gradient(90deg, var(--oc-blue) var(--oc-audio-progress), var(--oc-line) var(--oc-audio-progress)); }
.oc-audio-timeline input[type="range"]::-webkit-slider-thumb { width: 16px; height: 16px; margin-top: -5px; appearance: none; border: 3px solid var(--oc-surface); border-radius: 50%; background: var(--oc-blue); box-shadow: 0 0 0 1px var(--oc-blue); }
.oc-audio-timeline input[type="range"]::-moz-range-track { height: 6px; border-radius: 999px; background: var(--oc-line); }
.oc-audio-timeline input[type="range"]::-moz-range-progress { height: 6px; border-radius: 999px; background: var(--oc-blue); }
.oc-audio-timeline input[type="range"]::-moz-range-thumb { width: 11px; height: 11px; border: 3px solid var(--oc-surface); border-radius: 50%; background: var(--oc-blue); box-shadow: 0 0 0 1px var(--oc-blue); }
.oc-audio-timeline input[type="range"]:disabled { cursor: wait; opacity: .55; }
.oc-audio-time { display: flex; justify-content: space-between; color: var(--oc-muted); font-size: .7rem; font-variant-numeric: tabular-nums; font-weight: 700; }
.oc-narration audio { display: none; }
.oc-lesson-copy { font-size: 1.02rem; line-height: 1.72; }
.oc-lesson-copy p { margin: 0 0 16px; }
.oc-lesson-copy ul { margin: 18px 0; padding-left: 22px; }
.oc-lesson-copy li { margin: 7px 0; }
.oc-callout, .oc-activity { display: grid; gap: 5px; margin-top: 22px; padding: 15px 17px; border-left: 4px solid var(--oc-blue); border-radius: 0 10px 10px 0; background: var(--oc-blue-soft); }
.oc-activity { border-left-color: var(--oc-green); background: var(--oc-green-soft); }
.oc-callout strong, .oc-activity strong { color: var(--oc-heading); font-size: .78rem; text-transform: uppercase; letter-spacing: .07em; }
.oc-resources { margin-top: 22px; }
.oc-resources a { color: var(--oc-blue); font-weight: 750; }
.oc-player-card.is-checkpoint .oc-player-visual { min-height: 490px; }
.oc-player-card.is-checkpoint .oc-player-visual img { min-height: 490px; }
.oc-checkpoint-form h2, .oc-checkpoint-complete h2 { margin: 0 0 18px; color: var(--oc-heading); font-size: 1.5rem; line-height: 1.35; }
.oc-choice { display: flex; align-items: flex-start; gap: 11px; margin: 10px 0; padding: 13px 14px; border: 1px solid var(--oc-line); border-radius: 10px; background: var(--oc-surface); cursor: pointer; line-height: 1.45; }
.oc-choice:has(input:checked) { border-color: var(--oc-blue); background: var(--oc-blue-soft); }
.oc-choice input { margin-top: 4px; accent-color: var(--oc-blue); }
.oc-checkpoint-form .oc-button { margin-top: 12px; }
.oc-result { min-height: 24px; margin: 12px 0 0; color: var(--oc-heading); font-weight: 700; line-height: 1.45; }
.oc-checkpoint-complete { padding-top: 20px; }
.oc-checkpoint-complete p:last-child { color: var(--oc-muted); line-height: 1.6; }
.oc-player-controls { display: grid; grid-template-columns: minmax(200px, 1fr) auto auto; gap: 26px; align-items: center; margin-top: 16px; padding: 17px 20px; border: 1px solid var(--oc-line); border-radius: 15px; background: var(--oc-raised); box-shadow: var(--oc-shadow); }
.oc-jump { display: grid; gap: 5px; }
.oc-jump label { color: var(--oc-muted); font-size: .72rem; font-weight: 800; text-transform: uppercase; letter-spacing: .07em; }
.oc-jump select { width: 100%; min-height: 40px; padding: 0 34px 0 11px; border: 1px solid var(--oc-line); border-radius: 8px; background: var(--oc-surface); color: var(--oc-ink); font: inherit; font-size: .85rem; }
.oc-study-clocks { display: grid; gap: 6px; min-width: 230px; color: var(--oc-muted); font-size: .78rem; }
.oc-study-clocks span { display: flex; justify-content: space-between; gap: 15px; }
.oc-study-clocks strong { color: var(--oc-heading); font-variant-numeric: tabular-nums; }
.oc-page-actions { display: flex; gap: 8px; }
.oc-player-error, .oc-break-notice { margin: 14px 0 0; padding: 13px 16px; border: 1px solid #e2ad48; border-radius: 10px; background: var(--oc-amber-soft); color: #714200; line-height: 1.45; }
.oc-break-notice { display: flex; align-items: center; flex-wrap: wrap; gap: 10px; }
.oc-break-notice[hidden] { display: none; }
.oc-break-notice button { margin-left: auto; border: 0; background: transparent; color: inherit; cursor: pointer; font: inherit; font-weight: 800; text-decoration: underline; }

html[data-theme="dark"] {
  --oc-blue: #8fa7ff;
  --oc-blue-strong: #748ef2;
  --oc-blue-soft: #1c3152;
  --oc-green: #8bdbb2;
  --oc-green-soft: #173b2c;
  --oc-amber: #f4c46b;
  --oc-amber-soft: #3c2b14;
  --oc-shadow: 0 16px 38px rgba(0,0,0,.28);
}
html[data-theme="dark"] .oc-notice.warning, html[data-theme="dark"] .oc-player-error, html[data-theme="dark"] .oc-break-notice { border-color: #765524; color: #f7d48a; }
html[data-theme="dark"] .oc-notice.info { border-color: #3d5e8f; color: #bed0ff; }
html[data-theme="dark"] .oc-button:not(.secondary), html[data-theme="dark"] .oc-outline-action:not(:disabled), html[data-theme="dark"] .oc-audio-toggle { color: #071121; }
html[data-theme="dark"] .oc-image-caption { background: rgba(3, 10, 23, .84); }

.oc-nav a:focus-visible, .oc-nav button:focus-visible, .oc-button:focus-visible, .oc-outline-action:focus-visible, .oc-text-button:focus-visible, .oc-audio-toggle:focus-visible, .oc-audio-timeline input:focus-visible, .oc-jump select:focus-visible, .oc-choice:focus-within { outline: 3px solid var(--oc-focus); outline-offset: 3px; }

@media (max-width: 980px) {
  .oc-overview-grid { grid-template-columns: 1fr; }
  .oc-progress-card { position: static; }
  .oc-player-card { grid-template-columns: 1fr; }
  .oc-player-visual, .oc-player-visual img, .oc-player-card.is-checkpoint .oc-player-visual, .oc-player-card.is-checkpoint .oc-player-visual img { min-height: 320px; max-height: 390px; }
  .oc-player-controls { grid-template-columns: 1fr 1fr; }
  .oc-jump { grid-column: 1 / -1; }
}
@media (max-width: 760px) {
  .oc-header-inner, .oc-shell { width: min(100% - 24px, 1240px); }
  .oc-header-inner { min-height: 64px; }
  .oc-brand img { width: 32px; height: 32px; }
  .oc-nav { gap: 12px; font-size: .84rem; }
  .oc-overview-header { align-items: stretch; flex-direction: column; }
  .oc-overall-progress { width: 100%; min-height: 74px; }
  .oc-outline-row { grid-template-columns: 38px minmax(0, 1fr) auto; gap: 10px; padding: 13px 14px; }
  .oc-outline-status { grid-column: 2; }
  .oc-outline-action { grid-column: 3; grid-row: 1 / span 2; }
  .oc-player-topbar { grid-template-columns: 1fr auto; }
  .oc-player-course { display: none; }
  .oc-player-content { padding: 26px 22px; }
  .oc-player-content h1 { font-size: 2.15rem; }
  .oc-player-controls { grid-template-columns: 1fr; gap: 14px; }
  .oc-jump { grid-column: auto; }
  .oc-study-clocks { min-width: 0; }
  .oc-page-actions { justify-content: stretch; }
  .oc-page-actions .oc-button { flex: 1; }
}
@media (max-width: 480px) {
  .oc-shell { margin-top: 24px; }
  .oc-nav a { display: none; }
  .oc-card { border-radius: 14px; }
  .oc-section-heading { padding: 20px 18px 16px; }
  .oc-outline-row { grid-template-columns: 34px minmax(0, 1fr); }
  .oc-outline-action { grid-column: 2; grid-row: auto; width: 100%; }
  .oc-outline-status { grid-column: 2; }
  .oc-player-visual, .oc-player-visual img, .oc-player-card.is-checkpoint .oc-player-visual, .oc-player-card.is-checkpoint .oc-player-visual img { min-height: 250px; max-height: 280px; }
  .oc-image-caption { inset: auto 12px 12px; }
}
@media (prefers-reduced-motion: reduce) { * { scroll-behavior: auto !important; transition: none !important; } }