/* 常开心的小百科 v4 — museum essay design system */
:root {
  --space-1: 4px; --space-2: 8px; --space-3: 12px; --space-4: 16px;
  --space-5: 24px; --space-6: 32px; --space-7: 48px;
  /* Warm off-white + charcoal — semantic accents only */
  --paper: #FBF7F0; --paper-deep: #F0EBE3; --paper-card: #FFFcf8;
  --ink: #2C2824; --muted: #7A736C; --muted-soft: #A39C94;
  --sun: #E8B84A; --sun-soft: #F8E8C0;
  --water: #3B7CAD; --water-soft: #D6E7F2;
  --cloud: #B8B4C8; --cloud-soft: #E8E6F0;
  --land: #5A8A5A; --land-soft: #E2EDE2;
  /* Tiny Thomas-mood accents (logo/mascot only) */
  --engine-blue: #3B6FBF; --coach-red: #C45C4A;
  --accent: var(--water); --accent-deep: #2F628A; --accent-soft: var(--water-soft);
  --teal: #3D7A7A; --teal-soft: #D5E8E8;
  --shadow: 0 12px 36px rgba(44, 40, 36, 0.06);
  --shadow-sm: 0 3px 12px rgba(44, 40, 36, 0.04);
  --shadow-lift: 0 16px 40px rgba(44, 40, 36, 0.09);
  --radius: 24px; --radius-sm: 16px; --radius-xs: 12px;
  --touch: 48px; --max: 640px;
  --font: "PingFang SC", "Noto Sans SC", "Hiragino Sans GB", "Microsoft YaHei", system-ui, sans-serif;
  --ease: cubic-bezier(0.22, 0.61, 0.36, 1);
  --fluid-title: clamp(1.4rem, 1.15rem + 1.1vw, 1.85rem);
  --fluid-body: clamp(0.95rem, 0.9rem + 0.25vw, 1.05rem);
}

*, *::before, *::after { box-sizing: border-box; }
html { font-size: 17px; -webkit-tap-highlight-color: transparent; scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: var(--font);
  background:
    radial-gradient(900px 480px at 10% -6%, #F5EFE4 0%, transparent 55%),
    radial-gradient(700px 400px at 100% 0%, #EAF1F6 0%, transparent 50%),
    var(--paper);
  color: var(--ink);
  min-height: 100vh;
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
}
a { color: var(--water); text-decoration: none; }
a:hover { text-decoration: underline; text-underline-offset: 3px; }

.wrap {
  max-width: var(--max);
  margin: 0 auto;
  padding: var(--space-4) var(--space-5) var(--space-7);
}

/* —— Header —— */
.site-header {
  background: rgba(251, 247, 240, 0.9);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid rgba(44, 40, 36, 0.05);
  padding: var(--space-3) var(--space-5);
  position: sticky; top: 0; z-index: 40;
}
.site-header .inner {
  max-width: var(--max); margin: 0 auto;
  display: flex; align-items: center; gap: var(--space-3); flex-wrap: wrap;
}
.logo {
  font-weight: 700; font-size: 1.02rem; color: var(--ink);
  display: flex; align-items: center; gap: var(--space-2);
}
.logo .mark {
  display: inline-flex; align-items: center; justify-content: center;
  width: 28px; height: 28px; border-radius: 50%;
  background: linear-gradient(145deg, #F6C97A, #E8A84A);
  box-shadow: inset 0 -1px 0 rgba(0,0,0,0.06), 0 2px 6px rgba(232,168,74,0.3);
}
.logo .mark svg { width: 18px; height: 18px; }
.logo a { color: inherit; text-decoration: none; }
.nav-back {
  display: inline-flex; align-items: center; justify-content: center;
  min-height: 44px; padding: var(--space-2) var(--space-4);
  background: var(--paper-deep);
  border-radius: 999px;
  color: var(--ink); font-weight: 600; font-size: 0.88rem;
  text-decoration: none;
  transition: background 0.2s var(--ease);
}
.nav-back:hover { background: var(--water-soft); text-decoration: none; }

/* —— Index: calm museum cover —— */
.hero {
  background: linear-gradient(165deg, #FFFFFF 0%, var(--paper) 50%, #EEF3F7 100%);
  border-radius: var(--radius);
  padding: var(--space-6) var(--space-5) var(--space-5);
  margin: var(--space-5) 0 var(--space-5);
  box-shadow: var(--shadow);
  border: 1px solid rgba(44, 40, 36, 0.04);
  position: relative;
  overflow: hidden;
}
.hero::before {
  content: "";
  position: absolute; left: 0; right: 0; top: 0; height: 3px;
  background: repeating-linear-gradient(90deg,
    var(--engine-blue) 0 14px, transparent 14px 24px,
    var(--coach-red) 24px 38px, transparent 38px 48px,
    var(--sun) 48px 62px, transparent 62px 76px);
  opacity: 0.4;
}
.hero-mascot {
  position: absolute; right: 18px; bottom: 14px;
  width: 72px; height: 52px; opacity: 0.85;
  pointer-events: none;
}
.hero h1 {
  margin: 0 0 var(--space-3);
  font-size: clamp(1.6rem, 1.3rem + 1.5vw, 2.1rem);
  font-weight: 750;
  color: var(--ink);
  letter-spacing: -0.02em;
  line-height: 1.25;
}
.hero .eyebrow {
  display: inline-block;
  font-size: 0.72rem; font-weight: 650;
  letter-spacing: 0.08em;
  color: var(--teal);
  margin-bottom: var(--space-3);
  padding: 4px 12px;
  background: var(--teal-soft);
  border-radius: 999px;
}
.hero p {
  margin: 0;
  color: var(--muted);
  font-size: var(--fluid-body);
  max-width: 28em;
  line-height: 1.6;
}
.hero p + p { margin-top: 8px; font-size: 0.88rem; color: var(--muted-soft); }
.hero-stats {
  display: flex; flex-wrap: wrap; gap: var(--space-2);
  margin-top: var(--space-5);
}
.hero-stats span {
  font-size: 0.78rem; font-weight: 600;
  color: var(--ink);
  background: rgba(255,255,255,0.75);
  border: 1px solid rgba(44,40,36,0.05);
  padding: 6px 12px; border-radius: 999px;
}

.filters {
  display: flex; flex-wrap: wrap; gap: var(--space-2);
  margin: var(--space-2) 0 var(--space-4); align-items: center;
}
.search {
  flex: 1 1 100%;
  min-height: var(--touch);
  padding: 12px 18px;
  border: 1px solid rgba(44, 40, 36, 0.08);
  border-radius: 999px;
  font-size: 1rem;
  font-family: inherit;
  background: #fff;
  color: var(--ink);
  box-shadow: var(--shadow-sm);
  margin-bottom: 4px;
}
.search:focus { outline: none; border-color: var(--water); box-shadow: 0 0 0 3px var(--water-soft); }
.chip {
  min-height: 44px;
  padding: 8px 14px;
  border-radius: 999px;
  border: 1px solid rgba(44, 40, 36, 0.08);
  background: #fff;
  color: var(--muted);
  font-family: inherit;
  font-size: 0.86rem;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.2s var(--ease), color 0.2s var(--ease);
}
.chip:hover { color: var(--ink); }
.chip.active { background: var(--water); color: #fff; border-color: var(--water); }

.section-label {
  font-size: 0.78rem; font-weight: 650;
  color: var(--muted);
  letter-spacing: 0.05em;
  margin: var(--space-5) 0 var(--space-3);
  display: flex; align-items: center; gap: var(--space-2);
}
.section-label::after {
  content: ""; flex: 1; height: 1px;
  background: rgba(44,40,36,0.07);
}
.grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(148px, 1fr));
  gap: var(--space-3);
}
#grid-gold {
  grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
  margin-bottom: var(--space-2);
}
.card {
  display: flex; flex-direction: column;
  background: var(--paper-card);
  border: 1px solid rgba(44, 40, 36, 0.05);
  border-radius: var(--radius-sm);
  padding: var(--space-4) var(--space-3) var(--space-3);
  min-height: 118px;
  box-shadow: var(--shadow-sm);
  color: inherit;
  text-decoration: none;
  transition: transform 0.25s var(--ease), box-shadow 0.25s var(--ease);
  position: relative;
}
.card.gold {
  background: linear-gradient(165deg, #FFFFFF, #F7F4EE);
  border-color: rgba(232, 184, 74, 0.25);
}
.card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-lift);
  text-decoration: none;
}
.card .num {
  font-size: 0.7rem; font-weight: 700;
  color: var(--muted-soft);
  letter-spacing: 0.04em;
  margin-bottom: 6px;
}
.card.gold .num { color: var(--water); }
.card h2 {
  margin: 0;
  font-size: 0.95rem;
  font-weight: 700;
  line-height: 1.35;
  color: var(--ink);
  flex: 1;
}
.card .cat {
  margin-top: var(--space-3);
  font-size: 0.7rem;
  font-weight: 600;
  color: var(--teal);
  background: var(--teal-soft);
  align-self: flex-start;
  padding: 3px 8px;
  border-radius: 999px;
}
.card.hidden { display: none; }
.card .badge-gold {
  position: absolute; top: 10px; right: 10px;
  font-size: 0.62rem; font-weight: 700;
  color: #8A6A20;
  background: var(--sun-soft);
  padding: 2px 7px; border-radius: 999px;
}

/* —— Topic page —— */
.topic-page .topic-title {
  margin: var(--space-5) 0 var(--space-2);
  font-size: var(--fluid-title);
  font-weight: 750;
  line-height: 1.3;
  letter-spacing: -0.015em;
}
.topic-meta {
  margin: 0 0 var(--space-4);
  font-size: 0.84rem;
  color: var(--teal);
  font-weight: 600;
}
.topic-meta .gold-tag {
  display: inline-block;
  margin-left: 8px;
  font-size: 0.7rem;
  color: #8A6A20;
  background: var(--sun-soft);
  padding: 2px 8px;
  border-radius: 999px;
}

/* —— Essay stage (v4) —— */
.stage {
  background: transparent;
  border: none;
  box-shadow: none;
  padding: 0;
  margin-bottom: var(--space-5);
  overflow: visible;
}
.stage-v4 { padding: 0; }

.essay-lead {
  margin: 0 0 var(--space-3);
  font-size: 1.05rem;
  font-weight: 650;
  color: var(--ink);
  line-height: 1.5;
}

.essay-stage-wrap {
  width: 100%;
  max-width: 560px;
  margin: 0 auto;
  border-radius: var(--radius-sm);
  overflow: hidden;
  background: #dceaf2;
  box-shadow: var(--shadow);
  border: 1px solid rgba(44, 40, 36, 0.05);
}
.essay-canvas {
  display: block;
  width: 100%;
  max-width: 100%;
  touch-action: none;
  cursor: pointer;
}

/* Transport: play / replay / scrub — 12–24px under stage */
.essay-transport {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-2);
  margin-top: 18px;
  max-width: 560px;
  margin-left: auto;
  margin-right: auto;
}
.essay-icon-btn {
  min-height: 48px;
  min-width: 72px;
  padding: 10px 16px;
  border-radius: 999px;
  border: none;
  background: var(--water);
  color: #fff;
  font-family: inherit;
  font-size: 0.92rem;
  font-weight: 700;
  cursor: pointer;
  box-shadow: 0 4px 14px rgba(59, 124, 173, 0.25);
  transition: transform 0.2s var(--ease), background 0.2s var(--ease);
}
.essay-icon-btn:hover { background: var(--accent-deep); }
.essay-icon-btn:active { transform: scale(0.97); }
.essay-icon-btn.essay-icon-ghost {
  background: #fff;
  color: var(--ink);
  border: 1px solid rgba(44, 40, 36, 0.1);
  box-shadow: var(--shadow-sm);
}
.essay-icon-btn.essay-icon-ghost:hover { background: var(--paper-deep); }

.essay-scrub {
  flex: 1 1 160px;
  display: flex;
  align-items: center;
  gap: var(--space-2);
  background: #fff;
  border-radius: 999px;
  padding: 8px 14px;
  border: 1px solid rgba(44, 40, 36, 0.08);
  min-height: 48px;
}
.essay-scrub-label {
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--muted);
  white-space: nowrap;
}
.essay-scrub-input {
  flex: 1;
  min-width: 0;
  accent-color: var(--water);
  height: 28px;
  cursor: pointer;
}

.essay-caption {
  text-align: center;
  font-size: 1.05rem;
  font-weight: 650;
  color: var(--ink);
  margin: var(--space-4) auto var(--space-2);
  max-width: 32em;
  min-height: 1.55em;
  line-height: 1.5;
}
.essay-caption.pulse { animation: capPulse 0.5s var(--ease); }
@keyframes capPulse {
  0% { opacity: 0.35; transform: translateY(3px); }
  100% { opacity: 1; transform: none; }
}

.essay-so {
  text-align: center;
  font-size: 0.98rem;
  font-weight: 650;
  color: var(--water);
  margin: var(--space-2) auto var(--space-3);
  max-width: 30em;
  line-height: 1.5;
}

.essay-secondary {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  margin: var(--space-2) auto;
  max-width: 320px;
  background: #fff;
  border-radius: 999px;
  padding: 8px 14px;
  border: 1px solid rgba(44, 40, 36, 0.08);
  min-height: 48px;
}
.essay-secondary[hidden] { display: none !important; }
.essay-sec-label {
  font-size: 0.8rem; font-weight: 650; color: var(--muted); white-space: nowrap;
}
.essay-secondary input[type=range] { flex: 1; accent-color: var(--water); }

.essay-hint {
  text-align: center;
  font-size: 0.8rem;
  color: var(--muted-soft);
  margin: var(--space-3) 0 0;
}

/* Legacy v3 leftovers kept inert if any old HTML cached */
.step-nav, .stage-ui, .big-btn, .step-pill { display: none !important; }

/* —— Parent script —— */
.parent-script {
  background: #fff;
  border-radius: var(--radius-sm);
  padding: var(--space-4) var(--space-5);
  border: 1px solid rgba(44, 40, 36, 0.05);
  box-shadow: var(--shadow-sm);
  margin-bottom: var(--space-4);
}
.parent-script .label,
.learning-goal .label {
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  color: var(--muted-soft);
  margin-bottom: 6px;
}
.parent-script p {
  margin: 0;
  font-size: var(--fluid-body);
  color: var(--ink);
  line-height: 1.55;
}
.learning-goal {
  margin-top: var(--space-3);
  padding-top: var(--space-3);
  border-top: 1px solid rgba(44, 40, 36, 0.06);
  font-size: 0.92rem;
  color: var(--muted);
}

.pager {
  display: flex; justify-content: space-between; gap: var(--space-3);
  flex-wrap: wrap;
  margin: var(--space-5) 0;
}
.pager a {
  display: inline-flex; align-items: center;
  min-height: 48px;
  padding: 10px 16px;
  background: #fff;
  border-radius: 999px;
  border: 1px solid rgba(44, 40, 36, 0.08);
  color: var(--ink);
  font-weight: 600;
  font-size: 0.88rem;
  text-decoration: none;
  box-shadow: var(--shadow-sm);
}
.pager a:hover { background: var(--water-soft); text-decoration: none; }

.site-footer {
  text-align: center;
  padding: var(--space-5) var(--space-4) var(--space-7);
  font-size: 0.78rem;
  color: var(--muted-soft);
}

@media (max-width: 420px) {
  .wrap { padding-left: var(--space-4); padding-right: var(--space-4); }
  .hero { padding: var(--space-5) var(--space-4); }
  .hero-mascot { width: 56px; height: 40px; opacity: 0.7; }
  .essay-transport { gap: 8px; }
  .essay-icon-btn { min-width: 64px; padding: 10px 12px; font-size: 0.86rem; }
}