/* 단원 허브 페이지 — 확정 디자인 "종이 × 관측창"
   생성기: scripts/generate-hubs.ts · 토큰은 src/style.css와 동일 */
:root {
  --paper: #F7F6F3;
  --surface: #FFFFFF;
  --ink: #1A1D21;
  --ink-soft: #4B515B;
  --ink-mute: #878D98;
  --hairline: #E7E4DE;
  --hairline-strong: #D6D2CA;
  --phys: #3565F2; --chem: #E8590C; --bio: #12B886; --earth: #7048E8;
  --radius-card: 14px;
  --radius-ui: 9px;
  --radius-tag: 6px;
  --shadow-rest: 0 1px 2px rgba(26, 29, 33, 0.03);
  --shadow-lift: 0 10px 26px rgba(26, 29, 33, 0.08);
  --font-sans: 'Pretendard Variable', Pretendard, 'Apple SD Gothic Neo', -apple-system, sans-serif;
  --font-mono: 'IBM Plex Mono', 'SF Mono', ui-monospace, monospace;
  --ease: cubic-bezier(0.22, 0.7, 0.25, 1);
  --maxw: 1100px;
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  font-family: var(--font-sans);
  background: var(--paper);
  color: var(--ink);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}
a { color: inherit; text-decoration: none; }
.mono { font-family: var(--font-mono); }
.muted { color: var(--ink-mute); }
:focus-visible { outline: 2px solid var(--ink); outline-offset: 2px; border-radius: 3px; }

/* ── 상단바 (style.css와 동일) ── */
.skip-link {
  position: fixed; top: -52px; left: 16px; z-index: 200;
  background: var(--ink); color: var(--paper);
  font-size: 13px; font-weight: 700; padding: 11px 18px;
  border-radius: 0 0 10px 10px; transition: top 0.15s var(--ease);
}
.skip-link:focus-visible { top: 0; outline-offset: -3px; }
.topbar {
  position: sticky; top: 0; z-index: 50;
  background: color-mix(in srgb, var(--paper) 92%, transparent);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--hairline);
}
.topbar-in {
  max-width: 1380px; margin: 0 auto; padding: 0 32px;
  display: flex; align-items: center; gap: 32px; height: 60px;
}
.brand { display: flex; align-items: baseline; gap: 10px; flex: none; }
.brand .brand-mark { align-self: center; display: block; flex: none; }
.brand strong { font-size: 19px; font-weight: 800; letter-spacing: -0.02em; color: var(--ink); }
.brand .brand-tag { font-family: var(--font-mono); font-size: 11px; color: var(--ink-mute); letter-spacing: 0.08em; }
.nav-menu { display: flex; gap: 4px; flex: 1; }
.nav-item {
  font-size: 14px; font-weight: 500; color: var(--ink-soft);
  padding: 6px 12px; border-radius: 8px; white-space: nowrap;
  transition: color 0.18s var(--ease), background-color 0.18s var(--ease);
}
.nav-item:hover { color: var(--ink); background: rgba(26, 29, 33, 0.05); }

/* ── 본문 컨테이너 ── */
.hub-main {
  width: 100%; max-width: var(--maxw);
  margin: 0 auto; padding: 28px 32px 72px; flex: 1;
}

/* ── 브레드크럼 ── */
.crumbs {
  display: flex; flex-wrap: wrap; align-items: center; gap: 8px;
  font-size: 13px; color: var(--ink-mute); margin-bottom: 28px;
}
.crumbs a { color: var(--ink-soft); transition: color 0.15s var(--ease); }
.crumbs a:hover { color: var(--ink); }
.crumbs [aria-current="page"] { color: var(--ink); font-weight: 600; }
.crumb-sep { color: var(--hairline-strong); }

/* ── 헤더 ── */
.hub-header { margin-bottom: 40px; max-width: 760px; }
.hub-kicker {
  font-size: 12px; letter-spacing: 0.08em; color: var(--ink-mute);
  text-transform: uppercase; margin-bottom: 14px;
}
.hub-header h1 {
  font-size: clamp(28px, 4.2vw, 42px); font-weight: 800;
  letter-spacing: -0.025em; line-height: 1.15; color: var(--ink);
}
.hub-lede { margin-top: 16px; font-size: 16px; color: var(--ink-soft); line-height: 1.7; }
.hub-lede strong { color: var(--ink); font-weight: 700; }

/* ── 챕터 섹션 ── */
.chapter { margin-bottom: 44px; }
.chapter-title {
  font-size: 15px; font-weight: 700; color: var(--ink); margin-bottom: 16px;
  padding-bottom: 10px; border-bottom: 1px solid var(--hairline);
  letter-spacing: -0.01em;
}

/* ── 카드 그리드 공통 ── */
.sim-grid, .unit-grid, .course-grid {
  list-style: none; display: grid; gap: 14px;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
}
.sim-card > a, .unit-card > a, .course-card > a {
  display: flex; flex-direction: column; gap: 8px; height: 100%;
  background: var(--surface); border: 1px solid var(--hairline);
  border-radius: var(--radius-card); padding: 18px 18px 16px;
  box-shadow: var(--shadow-rest);
  transition: transform 0.18s var(--ease), box-shadow 0.18s var(--ease),
    border-color 0.18s var(--ease), background-color 0.18s var(--ease);
}
.sim-card > a:hover, .unit-card > a:hover, .course-card > a:hover {
  transform: translateY(-2px); box-shadow: var(--shadow-lift);
  border-color: var(--hairline-strong); background: #FBFAF8;
}

/* ── 시뮬 카드 ── */
.sim-meta { display: flex; align-items: center; gap: 8px; font-size: 12px; color: var(--ink-mute); }
.dot { width: 8px; height: 8px; border-radius: 50%; flex: none; display: inline-block; }
.dot-phys { background: var(--phys); }
.dot-chem { background: var(--chem); }
.dot-bio { background: var(--bio); }
.dot-earth { background: var(--earth); }
.sim-subject { font-weight: 600; color: var(--ink-soft); }
.sim-id { margin-left: auto; font-size: 11px; letter-spacing: 0.04em; }
.sim-title { font-size: 16px; font-weight: 700; color: var(--ink); letter-spacing: -0.01em; line-height: 1.4; }
.sim-desc { font-size: 13.5px; color: var(--ink-soft); line-height: 1.6; flex: 1; }
.sim-go { margin-top: 4px; font-size: 13px; font-weight: 600; color: var(--ink-mute); transition: color 0.15s var(--ease); }
.sim-card > a:hover .sim-go { color: var(--ink); }

/* ── 단원 카드 (과정 허브) ── */
.unit-meta { display: flex; align-items: center; gap: 10px; font-size: 11px; color: var(--ink-mute); letter-spacing: 0.04em; }
.unit-count { margin-left: auto; }
.unit-title { font-size: 17px; font-weight: 700; color: var(--ink); letter-spacing: -0.015em; }
.unit-sample { font-size: 13px; color: var(--ink-mute); line-height: 1.6; }

/* ── 과정 카드 (인덱스) ── */
.school-section { margin-bottom: 48px; }
.school-title {
  font-size: 14px; font-weight: 700; color: var(--ink-soft); margin-bottom: 18px;
  letter-spacing: 0.02em;
}
.course-meta { display: flex; align-items: center; gap: 10px; font-size: 11px; color: var(--ink-mute); letter-spacing: 0.04em; }
.course-units { margin-left: auto; }
.course-title { font-size: 19px; font-weight: 800; color: var(--ink); letter-spacing: -0.02em; }
.course-sample { font-size: 12.5px; color: var(--ink-mute); line-height: 1.6; }

/* ── 형제 단원 / 되돌아가기 ── */
.sibling-nav { margin-top: 8px; padding-top: 28px; border-top: 1px solid var(--hairline); }
.sibling-nav h2 { font-size: 14px; font-weight: 700; color: var(--ink-soft); margin-bottom: 14px; }
.sibling-nav ul { list-style: none; display: flex; flex-wrap: wrap; gap: 10px; }
.sibling-nav a {
  display: inline-flex; align-items: baseline; gap: 7px;
  font-size: 13.5px; color: var(--ink-soft);
  padding: 8px 14px; border: 1px solid var(--hairline);
  border-radius: 9999px; background: var(--surface);
  transition: border-color 0.15s var(--ease), color 0.15s var(--ease);
}
.sibling-nav a:hover { color: var(--ink); border-color: var(--hairline-strong); }
.sibling-nav .muted { font-family: var(--font-mono); font-size: 11px; }
.hub-back { margin-top: 36px; font-size: 14px; }
.hub-back a { color: var(--ink-soft); font-weight: 600; transition: color 0.15s var(--ease); }
.hub-back a:hover { color: var(--ink); }

/* ── 푸터 (style.css와 동일) ── */
.footer { border-top: 1px solid var(--hairline); margin-top: auto; }
.footer-in {
  max-width: 1380px; margin: 0 auto; padding: 24px 32px 36px;
  display: flex; align-items: baseline; gap: 24px;
  font-size: 13px; color: var(--ink-mute); flex-wrap: wrap;
}
.footer-in strong { color: var(--ink); font-weight: 700; }
.footer-tag { font-family: var(--font-mono); font-size: 11px; letter-spacing: 0.1em; }
.footer-nav { margin-left: auto; display: flex; gap: 18px; }
.footer-nav a { color: var(--ink-mute); transition: color 0.15s var(--ease); }
.footer-nav a:hover { color: var(--ink); }

/* ── 반응형 ── */
@media (max-width: 640px) {
  .topbar-in { padding: 0 18px; gap: 14px; height: 56px; }
  .brand .brand-tag { display: none; }
  .nav-menu { gap: 2px; justify-content: flex-end; }
  .nav-item { padding: 6px 9px; font-size: 13px; }
  .hub-main { padding: 22px 18px 56px; }
  .sim-grid, .unit-grid, .course-grid { grid-template-columns: 1fr; }
  .footer-in { padding: 22px 18px 30px; gap: 14px; }
  .footer-nav { margin-left: 0; width: 100%; flex-wrap: wrap; }
}
@media (prefers-reduced-motion: reduce) {
  * { transition: none !important; }
  .sim-card > a:hover, .unit-card > a:hover, .course-card > a:hover { transform: none; }
}