/* ========================================
   Dunhuang project page — manual-inspired
   Warm paper tones, academic elegance
   ======================================== */
:root {
  --paper: #f5f0e6;
  --ink: #2b2124;
  --ink-light: #6b5e58;
  --gold: #c9bda4;
  --gold-dim: #b8a88a;
  --white: #fafaf5;
  --divider: rgba(0,0,0,0.06);
  --font: 'Noto Serif SC', 'STSong', 'SimSun', serif;
  --font-mono: 'Inter', monospace;
}

*, *::before, *::after { margin:0; padding:0; box-sizing:border-box; }
html {
  font-size: 16px;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font);
  font-weight: 400;
  -webkit-font-smoothing: antialiased;
}
body { overflow-x: hidden; }
a { color: inherit; text-decoration: none; }
img { display: block; max-width: 100%; }

/* Noise overlay */
.noise-bg { position: fixed; inset:0; z-index:9999; pointer-events:none; opacity:0.5; mix-blend-mode:multiply; }

/* Loader splash */
.dh-loader {
  position: fixed; inset: 0; z-index: 20000;
  background: var(--paper);
  display: flex; align-items: center; justify-content: center;
  cursor: pointer;
  transition: opacity 0.5s ease;
}
.dh-loader.is-dismissed { opacity: 0; pointer-events: none; }
.dh-loader-inner {
  text-align: center; max-width: 560px; padding: 40px;
  transition: transform 0.15s ease-out;
}
.dh-loader-text {
  font-family: var(--font);
  font-size: 16px; font-weight: 300; line-height: 2;
  color: var(--ink-light);
  margin: 20px 0 24px;
  opacity: 0; transform: translateY(12px);
}
.dh-loader-text.in { opacity: 1; transform: translateY(0); transition: opacity 0.7s ease 0.55s, transform 0.7s ease 0.55s; }

.dh-meta {
  font-family: var(--font); font-size: 15px; font-weight: 300;
  color: var(--ink-light); letter-spacing: 0.04em;
  opacity: 0; transform: translateY(10px);
}
.dh-meta.in { opacity: 1; transform: translateY(0); transition: opacity 0.6s ease 0.65s, transform 0.6s ease 0.65s; }

.dh-loader-line2 { opacity: 0; transform: scaleX(0); }
.dh-loader-line2.in { opacity: 1; transform: scaleX(1); transition: opacity 0.5s ease 0.8s, transform 0.5s ease 0.8s; }

.dh-loader-hint {
  font-family: var(--font);
  font-size: 13px; font-weight: 400; letter-spacing: 0.08em;
  color: var(--ink);
  margin-top: 8px;
  opacity: 0; transform: translateY(8px);
}
.dh-loader-hint.in { opacity: 1; transform: translateY(0); transition: opacity 0.6s ease 1.0s, transform 0.6s ease 1.0s; }

.dh-loader-enter {
  font-family: var(--font-mono);
  font-size: 11px; letter-spacing: 0.15em;
  color: var(--ink-light);
  margin-top: 24px;
  opacity: 0;
}
.dh-loader-enter.in { opacity: 1; transition: opacity 0.6s ease 1.2s; animation: pulse 2s ease-in-out infinite 1.2s; }
@keyframes pulse {
  0%, 100% { opacity: 0.3; }
  50% { opacity: 0.8; }
}

/* Title + sub: same pattern */
.dh-title {
  font-family: var(--font); font-size: clamp(48px, 7vw, 88px);
  font-weight: 500; letter-spacing: 0.06em; line-height: 1.1;
  color: var(--ink);
  opacity: 0; transform: translateY(16px);
}
.dh-title.in { opacity: 1; transform: translateY(0); transition: opacity 0.9s ease, transform 0.9s ease; }

.dh-sub {
  font-family: var(--font-mono); font-size: 13px; letter-spacing: 0.2em;
  color: var(--ink-light); margin-top: 12px; text-transform: uppercase;
  opacity: 0; transform: translateY(12px);
}
.dh-sub.in { opacity: 1; transform: translateY(0); transition: opacity 0.7s ease 0.15s, transform 0.7s ease 0.15s; }

.dh-line { width: 40px; height: 1px; background: var(--gold); margin: 28px auto; transform-origin: center; opacity: 0; transform: scaleX(0); }
.dh-line.in { opacity: 1; transform: scaleX(1); transition: opacity 0.5s ease 0.35s, transform 0.5s ease 0.35s; }

/* Header */
.dh-header {
  position: fixed; top:0; left:0; right:0; z-index:90;
  display: flex; justify-content: space-between; align-items: flex-start;
  padding: 24px 32px;
  mix-blend-mode: difference;
}
.dh-back {
  font-family: var(--font-mono); font-size: 13px; letter-spacing: 0.12em;
  color: var(--ink); opacity: 0.6; transition: opacity 0.3s;
}
.dh-back:hover { opacity: 1; }
.dh-header-site {
  font-family: var(--font-mono); font-size: 14px; font-weight: 500; letter-spacing: 0.15em;
  color: var(--ink); opacity: 0.9;
  padding: 10px 24px;
  border: 1.5px solid var(--ink);
  transition: background 0.3s, color 0.3s, box-shadow 0.3s;
  animation: dh-pulse 2.2s ease-in-out infinite;
}
.dh-header-site:hover {
  background: var(--ink); color: var(--paper); opacity: 1;
  box-shadow: 0 0 24px rgba(0,0,0,0.08);
  animation: none;
}
@keyframes dh-pulse {
  0%, 100% { box-shadow: 0 0 0 0 rgba(0,0,0,0.12); }
  50% { box-shadow: 0 0 0 6px rgba(0,0,0,0); }
}
.dh-lang {
  font-family: var(--font); font-size: 13px; font-weight: 300;
  color: var(--ink-light); letter-spacing: 0.05em;
}

/* Cover */
.dh-cover {
  display: flex; min-height: 100vh; align-items: center;
  padding: 80px;
  gap: 80px;
}
.dh-cover-img { flex: 1; max-width: 500px; }
.dh-cover-img img { width: 100%; box-shadow: 0 2px 24px rgba(0,0,0,0.08); }
.dh-cover-text { flex: 1; }
.dh-title {
  font-family: var(--font); font-size: clamp(48px, 7vw, 88px);
  font-weight: 500; letter-spacing: 0.06em; line-height: 1.1;
  color: var(--ink);
}
.dh-sub {
  font-family: var(--font-mono); font-size: 13px; letter-spacing: 0.2em;
  color: var(--ink-light); margin-top: 12px; text-transform: uppercase;
}
.dh-line { width: 40px; height: 1px; background: var(--gold); margin: 28px auto; transform-origin: center; }
.dh-meta {
  font-family: var(--font); font-size: 15px; font-weight: 300;
  color: var(--ink-light); letter-spacing: 0.04em;
}

/* Sections */
.dh-section {
  max-width: 720px; margin: 0 auto; padding: 80px 48px;
}
.dh-text-block { }
.dh-lead {
  font-family: var(--font); font-size: 22px; font-weight: 300;
  line-height: 1.8; color: var(--ink);
}
.dh-body {
  font-family: var(--font); font-size: 15px; font-weight: 300;
  line-height: 2; color: var(--ink-light);
  margin-top: 24px;
}
.dh-h2 {
  font-family: var(--font); font-size: 28px; font-weight: 500;
  letter-spacing: 0.04em; color: var(--ink);
  margin-bottom: 16px;
}

/* Floating info panel */
.dh-info { position: fixed; bottom: 32px; right: 24px; z-index: 100; }
.dh-info-toggle {
  width: 36px; height: 36px; border-radius: 50%;
  background: var(--ink); color: var(--paper);
  font-family: var(--font); font-size: 16px; font-weight: 500; font-style: italic;
  display: flex; align-items: center; justify-content: center;
  cursor: pointer; border: none;
  transition: background 0.3s, transform 0.3s;
  box-shadow: 0 2px 12px rgba(0,0,0,0.12);
}
.dh-info-toggle:hover { background: #000; transform: scale(1.08); }
.dh-info-panel {
  position: absolute; bottom: 44px; right: 0;
  width: 380px;
  background: rgba(245, 240, 230, 0.78);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid rgba(0,0,0,0.04);
  padding: 20px;
  opacity: 0; transform: translateY(8px);
  pointer-events: none;
  transition: opacity 0.3s, transform 0.3s;
  box-shadow: 0 1px 16px rgba(0,0,0,0.04);
}
.dh-info.is-open .dh-info-panel { opacity: 1; transform: translateY(0); pointer-events: auto; }
.dh-info-panel h3, .dh-info-panel h4 {
  font-family: var(--font); font-size: 13px; font-weight: 500; letter-spacing: 0.03em;
  color: var(--ink);
}
.dh-info-panel h3 { margin-bottom: 8px; }
.dh-info-panel h4 { margin: 12px 0 8px; }
.dh-info-panel p {
  font-family: var(--font); font-size: 11px; font-weight: 300;
  line-height: 1.6; color: var(--ink-light);
  margin-bottom: 8px;
}
.dh-info-panel p .label {
  display: block;
  font-family: var(--font); font-size: 11px; font-weight: 500;
  color: var(--ink); letter-spacing: 0.04em;
  margin-bottom: 1px;
}

/* Manual spreads — full bleed */
.dh-manual {
  width: 100%; padding: 0;
}
.dh-manual-grid {
  display: flex; flex-direction: column;
}
/* Loading hint */
.dh-loading-hint {
  text-align: center;
  font-family: var(--font-mono);
  font-size: 11px; letter-spacing: 0.12em;
  color: rgba(250,250,250,0.35);
  padding: 16px 0 24px;
  transition: opacity 0.4s ease;
}
.dh-manual-grid img {
  width: 100%; display: block;
}
.dh-spread-img {
  width: 100%;
  box-shadow: 0 1px 12px rgba(0,0,0,0.06);
  transition: filter .5s ease, transform .5s ease;
}
/* Blur-up: tiny placeholder is blurry, sharpens when mid loads */
.dh-spread-img.blur-up {
  filter: blur(10px);
  transform: scale(1.03);
}

/* Palette */
.dh-palette { display: grid; grid-template-columns: repeat(3,1fr); gap: 12px; }
.dh-swatch {
  aspect-ratio: 3/4; display: flex; align-items: flex-end; padding: 16px;
  font-family: var(--font); font-size: 16px; font-weight: 400;
  color: #fff; text-shadow: 0 1px 3px rgba(0,0,0,0.5);
}
.dh-swatch span { line-height: 1.4; }
.dh-swatch small { font-size: 12px; font-weight: 300; opacity: 0.7; display: block; }

/* CTA */
.dh-cta { text-align: center; padding: 120px 48px; }
.dh-link {
  display: inline-block; margin-top: 24px;
  font-family: var(--font-mono); font-size: 13px; letter-spacing: 0.1em;
  color: var(--ink); padding: 14px 32px;
  border: 1px solid var(--ink);
  transition: background 0.3s, color 0.3s;
}
.dh-link:hover { background: var(--ink); color: var(--paper); }
.dh-note {
  font-size: 12px; color: var(--ink-light); margin-top: 16px;
  font-family: var(--font); font-weight: 200;
}

/* Footer */
.dh-footer {
  text-align: center; padding: 48px;
  font-family: var(--font-mono); font-size: 11px;
  color: var(--ink-light); letter-spacing: 0.15em;
}

@media (max-width: 768px) {
  .dh-cover { flex-direction: column; padding: 120px 32px 60px; gap: 40px; }
  .dh-cover-img { max-width: 100%; }
  .dh-palette { grid-template-columns: repeat(2,1fr); }
}