:root {
  --canvas: #f5f5f7;
  --surface: #ffffff;
  --surface-raised: #fbfbfd;
  --line: #e2e4e9;
  --line-strong: #c8cdd7;
  --text: #1d1d1f;
  --muted: #5f636b;
  --subtle: #565b64;
  --accent: #1769e0;
  --accent-strong: #0b56c8;
  --content: 1480px;
  color-scheme: light;
  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: #fff; }
.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-radius: 9px; background: #1d1d1f; color: #fff; font-size: 12px; letter-spacing: -.04em; box-shadow: 0 8px 22px rgba(16,24,40,.14); }
.library-intro { width: min(var(--content), calc(100% - 48px)); min-height: 310px; margin: 0 auto; padding: 72px 0 58px; 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(--accent); font-size: 11px; font-weight: 760; letter-spacing: .14em; text-transform: uppercase; }
h1, h2, h3, p { overflow-wrap: anywhere; }
h1 { margin: 0; font-size: clamp(46px,6.5vw,82px); line-height: .95; letter-spacing: -.065em; }
h1 span { color: #86868b; font-weight: 420; }
.library-count { margin: 22px 0 0; color: var(--muted); font-size: 15px; }
.library-count strong { color: var(--text); }
.catalog-tools { display: grid; gap: 14px; }
.search-field { min-height: 50px; padding: 0 15px; display: flex; align-items: center; gap: 10px; border: 1px solid var(--line); border-radius: 14px; background: rgba(255,255,255,.82); box-shadow: 0 14px 40px rgba(35,45,67,.06); }
.search-field:focus-within { border-color: var(--accent); box-shadow: 0 0 0 3px rgba(23,105,224,.12); }
.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: #656a73; }
.filters { display: flex; flex-wrap: wrap; gap: 8px; }
.filter { min-height: 40px; padding: 8px 14px; border: 1px solid var(--line); border-radius: 999px; background: rgba(255,255,255,.56); color: var(--muted); cursor: pointer; }
.filter:hover, .filter.is-active { border-color: #b8c0ce; background: #fff; color: var(--text); box-shadow: 0 8px 22px rgba(35,45,67,.07); }
.filter:focus-visible, a:focus-visible, input:focus-visible { outline: 3px solid rgba(23,105,224,.35); outline-offset: 3px; }
.catalog { width: min(var(--content), calc(100% - 48px)); margin: 0 auto; padding: 52px 0 88px; }
.catalog-heading { margin-bottom: 24px; display: flex; align-items: end; justify-content: space-between; gap: 24px; }
.catalog-heading h2 { margin: 0; font-size: clamp(25px,3vw,38px); letter-spacing: -.04em; }
.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: 26px; background: var(--surface); box-shadow: 0 20px 55px rgba(31,42,64,.07); transition: transform 180ms ease, box-shadow 180ms ease; }
.course-card:hover { transform: translateY(-3px); box-shadow: 0 28px 74px rgba(31,42,64,.11); }
@media (min-width: 901px) { .course-card:last-child:nth-child(odd) { grid-column: 1 / -1; width: calc(50% - 11px); justify-self: center; } }
.course-cover { position: relative; display: block; aspect-ratio: 16/8.4; overflow: hidden; border-bottom: 1px solid var(--line); background: #f2f4f8; }
.course-cover::after { content: ""; position: absolute; inset: 50% 0 0; background: linear-gradient(180deg,transparent,rgba(247,248,251,.46)); 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(1.018); }
.course-area, .course-state { position: absolute; z-index: 1; top: 16px; padding: 7px 11px; border: 1px solid rgba(255,255,255,.9); border-radius: 999px; background: rgba(255,255,255,.78); backdrop-filter: blur(14px); color: #30343a; box-shadow: 0 8px 24px rgba(30,42,66,.08); font-size: 11px; font-weight: 700; }
.course-area { left: 16px; }
.course-state { right: 16px; color: var(--accent-strong); }
.course-state.new { color: #9b4e12; }
.course-body { min-height: 276px; padding: 26px; display: flex; flex-direction: column; justify-content: space-between; gap: 22px; }
.course-kicker { margin: 0 0 8px; color: var(--subtle); font-size: 11px; font-weight: 740; letter-spacing: .08em; text-transform: uppercase; }
.course-card h3 { margin: 0; font-size: clamp(24px,2.6vw,36px); line-height: 1.06; letter-spacing: -.04em; }
.course-card h3 a { text-decoration: none; }
.course-card h3 a::after { content: " ↗"; color: var(--subtle); font-size: .6em; vertical-align: .15em; }
.course-card h3 a:hover { color: var(--accent-strong); }
.course-card h3 + p { max-width: 700px; margin: 14px 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: 5px; overflow: hidden; border-radius: 999px; background: #e8ebf1; }
.progress-track span { display: block; width: 0; height: 100%; border-radius: inherit; background: linear-gradient(90deg,#1769e0,#6e63ff); transition: width 300ms ease; }
.course-meta { margin: 0; padding-top: 18px; 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: #484d55; font-size: 12px; }
.empty-state { padding: 80px 24px; border: 1px dashed var(--line-strong); border-radius: 22px; text-align: center; background: #fff; }
.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 72px; padding: 60px; border: 1px solid var(--line); border-radius: 28px; background: linear-gradient(145deg,#fff,#f0f3f8); box-shadow: 0 22px 64px rgba(31,42,64,.07); }
.learning-principles > h2 { max-width: 940px; margin: 0; font-size: clamp(34px,4.8vw,62px); line-height: .98; letter-spacing: -.055em; }
.principle-grid { margin-top: 50px; display: grid; grid-template-columns: repeat(3,1fr); gap: 30px; }
.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: 34px 0 8px; font-size: 19px; }
.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: 36px; } .course-grid { grid-template-columns: 1fr; } .principle-grid { grid-template-columns: 1fr; } .learning-principles { padding: 40px 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: 46px 0 38px; } h1 { font-size: clamp(46px,15vw,64px); } .catalog { padding-top: 36px; } .catalog-heading { align-items: start; flex-direction: column; gap: 9px; } .course-cover { aspect-ratio: 16/9; } .course-body { min-height: 0; padding: 21px; } .course-meta { grid-template-columns: 1fr 1fr; } .course-meta div:last-child { grid-column: 1/-1; } .learning-principles { margin-bottom: 36px; padding: 32px 21px; } 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; } }