:root {
  --canvas: #080b0d;
  --surface: #101618;
  --surface-raised: #151d20;
  --line: #222b2f;
  --line-strong: #354146;
  --text: #f1f4f5;
  --muted: #9ca7ac;
  --subtle: #8a969b;
  --accent: #77a9ff;
  --accent-strong: #9bc0ff;
  --content: 1480px;
  color-scheme: dark;
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Display", "Helvetica Neue", Arial, sans-serif;
}
* { box-sizing: border-box; }
html { background: var(--canvas); }
body { margin: 0; min-width: 320px; background: var(--canvas); color: var(--text); font-size: 16px; line-height: 1.5; -webkit-font-smoothing: antialiased; }
a { color: inherit; }
button, input { font: inherit; }
button, a { -webkit-tap-highlight-color: transparent; }
img { max-width: 100%; display: block; }
[hidden] { display: none !important; }
.skip-link { position: fixed; z-index: 100; top: 12px; left: 12px; transform: translateY(-180%); padding: 11px 15px; border-radius: 10px; background: var(--text); color: var(--canvas); }
.skip-link:focus { transform: translateY(0); }
.visually-hidden { position: absolute !important; width: 1px !important; height: 1px !important; padding: 0 !important; margin: -1px !important; overflow: hidden !important; clip: rect(0 0 0 0) !important; white-space: nowrap !important; border: 0 !important; }
.library-header { width: min(var(--content), calc(100% - 48px)); min-height: 72px; margin: 0 auto; display: flex; align-items: center; justify-content: space-between; gap: 24px; border-bottom: 1px solid var(--line); }
.library-header > p { margin: 0; color: var(--subtle); font-size: 13px; }
.brand { display: inline-flex; align-items: center; gap: 11px; text-decoration: none; font-size: 14px; font-weight: 720; }
.brand-mark { width: 30px; height: 30px; display: grid; place-items: center; border: 1px solid var(--line-strong); border-radius: 9px; background: #151b1e; color: var(--accent-strong); font-size: 12px; letter-spacing: -0.04em; }
.library-intro { width: min(var(--content), calc(100% - 48px)); min-height: 250px; margin: 0 auto; padding: 60px 0 54px; display: grid; grid-template-columns: minmax(0, 1fr) minmax(360px, 470px); align-items: end; gap: 64px; border-bottom: 1px solid var(--line); }
.eyebrow { margin: 0 0 12px; color: var(--subtle); font-size: 11px; font-weight: 760; letter-spacing: 0.14em; text-transform: uppercase; }
h1, h2, h3, p { overflow-wrap: anywhere; }
h1 { margin: 0; font-size: clamp(42px, 6vw, 74px); line-height: 0.98; letter-spacing: -0.06em; }
h1 span { color: #737b7f; font-weight: 420; }
.library-count { margin: 20px 0 0; color: var(--muted); font-size: 14px; }
.library-count strong { color: var(--text); }
.catalog-tools { display: grid; gap: 14px; }
.search-field { min-height: 48px; padding: 0 15px; display: flex; align-items: center; gap: 10px; border: 1px solid var(--line); border-radius: 12px; background: #0c1012; }
.search-field:focus-within { border-color: var(--accent); box-shadow: 0 0 0 3px rgba(119, 169, 255, 0.15); }
.search-field svg { width: 18px; fill: none; stroke: var(--subtle); stroke-width: 1.8; stroke-linecap: round; }
.search-field input { width: 100%; border: 0; outline: 0; background: transparent; color: var(--text); }
.search-field input::placeholder { color: #647075; }
.filters { display: flex; flex-wrap: wrap; gap: 8px; }
.filter { min-height: 40px; padding: 8px 13px; border: 1px solid var(--line); border-radius: 10px; background: transparent; color: var(--muted); cursor: pointer; }
.filter:hover, .filter.is-active { border-color: var(--line-strong); background: var(--surface); color: var(--text); }
.filter:focus-visible, a:focus-visible, input:focus-visible { outline: 2px solid var(--accent); outline-offset: 3px; }
.catalog { width: min(var(--content), calc(100% - 48px)); margin: 0 auto; padding: 46px 0 80px; }
.catalog-heading { margin-bottom: 22px; display: flex; align-items: end; justify-content: space-between; gap: 24px; }
.catalog-heading h2 { margin: 0; font-size: clamp(24px, 3vw, 36px); letter-spacing: -0.035em; }
.catalog-heading > p { margin: 0; color: var(--subtle); font-size: 13px; }
.course-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 22px; }
.course-card { overflow: hidden; border: 1px solid var(--line); border-radius: 18px; background: var(--surface); transition: transform 180ms ease, border-color 180ms ease; }
.course-card:hover { transform: translateY(-3px); border-color: var(--line-strong); }
.course-cover { position: relative; display: block; aspect-ratio: 16 / 8.3; overflow: hidden; border-bottom: 1px solid var(--line); background: #0a0e10; }
.course-cover::after { content: ""; position: absolute; inset: 0; background: linear-gradient(180deg, transparent 48%, rgba(8,11,13,.84) 100%); pointer-events: none; }
.course-cover img { width: 100%; height: 100%; object-fit: cover; transition: transform 500ms cubic-bezier(.2,.8,.2,1); }
.course-card:hover .course-cover img { transform: scale(1.025); }
.course-area, .course-state { position: absolute; z-index: 1; top: 15px; padding: 7px 10px; border: 1px solid rgba(255,255,255,.16); border-radius: 999px; background: rgba(8,11,13,.72); backdrop-filter: blur(12px); color: #edf2f4; font-size: 11px; font-weight: 700; }
.course-area { left: 15px; }
.course-state { right: 15px; color: var(--accent-strong); }
.course-state.new { color: #f1c980; }
.course-body { min-height: 265px; padding: 23px; display: flex; flex-direction: column; justify-content: space-between; gap: 22px; }
.course-kicker { margin: 0 0 7px; color: var(--subtle); font-size: 11px; font-weight: 740; letter-spacing: .08em; text-transform: uppercase; }
.course-card h3 { margin: 0; font-size: clamp(22px, 2.4vw, 31px); line-height: 1.08; letter-spacing: -.035em; }
.course-card h3 a { text-decoration: none; }
.course-card h3 a::after { content: " ↗"; color: var(--subtle); font-size: .62em; vertical-align: .14em; }
.course-card h3 a:hover { color: var(--accent-strong); }
.course-card h3 + p { max-width: 680px; margin: 13px 0 0; color: var(--muted); }
.course-progress { display: grid; grid-template-columns: minmax(0, 1fr) auto; align-items: center; gap: 12px; color: var(--subtle); font-size: 11px; }
.progress-track { height: 4px; overflow: hidden; border-radius: 999px; background: #263034; }
.progress-track span { display: block; width: 0; height: 100%; border-radius: inherit; background: var(--accent); transition: width 300ms ease; }
.course-meta { margin: 0; padding-top: 17px; display: grid; grid-template-columns: repeat(3, 1fr); gap: 14px; border-top: 1px solid var(--line); }
.course-meta div { min-width: 0; }
.course-meta dt { color: var(--subtle); font-size: 10px; text-transform: uppercase; letter-spacing: .08em; }
.course-meta dd { margin: 4px 0 0; color: #cbd2d5; font-size: 12px; }
.empty-state { padding: 80px 24px; border: 1px dashed var(--line-strong); border-radius: 18px; text-align: center; }
.empty-state h3 { margin: 0; font-size: 24px; }
.empty-state p { margin: 8px 0 0; color: var(--muted); }
.learning-principles { width: min(var(--content), calc(100% - 48px)); margin: 0 auto 70px; padding: 56px; border: 1px solid var(--line); border-radius: 20px; background: var(--surface); }
.learning-principles > h2 { max-width: 900px; margin: 0; font-size: clamp(32px, 4.6vw, 58px); line-height: 1; letter-spacing: -.05em; }
.principle-grid { margin-top: 48px; display: grid; grid-template-columns: repeat(3, 1fr); gap: 28px; }
.principle-grid article { padding-top: 18px; border-top: 1px solid var(--line-strong); }
.principle-grid span { color: var(--accent); font-size: 12px; font-weight: 760; }
.principle-grid h3 { margin: 32px 0 8px; font-size: 18px; }
.principle-grid p { margin: 0; color: var(--muted); font-size: 14px; }
footer { width: min(var(--content), calc(100% - 48px)); min-height: 80px; margin: 0 auto; display: flex; align-items: center; justify-content: space-between; gap: 20px; border-top: 1px solid var(--line); color: var(--subtle); font-size: 12px; }
@media (max-width: 900px) {
  .library-intro { grid-template-columns: 1fr; gap: 34px; }
  .course-grid { grid-template-columns: 1fr; }
  .principle-grid { grid-template-columns: 1fr; }
  .learning-principles { padding: 38px 28px; }
}
@media (max-width: 620px) {
  .library-header, .library-intro, .catalog, .learning-principles, footer { width: min(100% - 28px, var(--content)); }
  .library-header { min-height: 62px; }
  .library-header > p { display: none; }
  .library-intro { min-height: 0; padding: 42px 0 36px; }
  h1 { font-size: clamp(42px, 15vw, 60px); }
  .catalog { padding-top: 34px; }
  .catalog-heading { align-items: start; flex-direction: column; gap: 9px; }
  .course-cover { aspect-ratio: 16 / 9; }
  .course-body { min-height: 0; padding: 20px; }
  .course-meta { grid-template-columns: 1fr 1fr; }
  .course-meta div:last-child { grid-column: 1 / -1; }
  .learning-principles { margin-bottom: 36px; padding: 30px 20px; }
  footer { padding: 22px 0; align-items: flex-start; flex-direction: column; }
}
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { scroll-behavior: auto !important; transition-duration: .01ms !important; animation-duration: .01ms !important; animation-iteration-count: 1 !important; }
}