/* 行迹 ATLAS — shared theme */
:root {
  --ink: #0f0d0a;
  --ink-2: #171410;
  --ink-3: #201c15;
  --paper: #f3ede1;
  --paper-dim: #d8d0bf;
  --gold: #c9a86a;
  --gold-bright: #e6cd96;
  --rust: #c2603a;
  --teal: #52a08f;
  --blue: #6b93c4;
  --muted: #97907f;
  --dim: #6e6759;
  --line: rgba(201, 168, 106, 0.25);
  --line-soft: rgba(201, 168, 106, 0.13);
  --serif: "Noto Serif SC", "Songti SC", "STSong", "SimSun", Georgia, serif;
  --sans: "Noto Sans SC", "PingFang SC", "Microsoft YaHei", -apple-system, sans-serif;
  --latin: "Cormorant Garamond", Georgia, "Times New Roman", serif;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  font-family: var(--sans);
  background: var(--ink);
  color: var(--paper);
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

::selection { background: rgba(201, 168, 106, 0.35); color: #fff; }

a { color: inherit; text-decoration: none; }
img { display: block; }

.grain::after {
  content: "";
  position: fixed;
  inset: -50%;
  width: 200%;
  height: 200%;
  pointer-events: none;
  z-index: 2000;
  opacity: 0.05;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 240 240' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.85' numOctaves='2' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
  animation: grain-shift 9s steps(6) infinite;
}

@keyframes grain-shift {
  0%, 100% { transform: translate(0, 0); }
  20% { transform: translate(-2%, 2%); }
  40% { transform: translate(2%, -1%); }
  60% { transform: translate(-1%, -2%); }
  80% { transform: translate(1%, 2%); }
}

.site-nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 20px clamp(20px, 5vw, 64px);
  transition: background 0.4s, border-color 0.4s, padding 0.4s;
  border-bottom: 1px solid transparent;
}

.site-nav.scrolled {
  background: rgba(15, 13, 10, 0.88);
  backdrop-filter: blur(14px);
  border-bottom-color: var(--line-soft);
  padding-top: 14px;
  padding-bottom: 14px;
}

.wordmark {
  display: flex;
  align-items: baseline;
  gap: 10px;
}

.wordmark .zh {
  font-family: var(--serif);
  font-size: 21px;
  font-weight: 700;
  letter-spacing: 0.35em;
  color: var(--paper);
}

.wordmark .en {
  font-family: var(--latin);
  font-size: 13px;
  letter-spacing: 0.45em;
  color: var(--gold);
  text-transform: uppercase;
}

.nav-links { display: flex; gap: 30px; align-items: center; }

.nav-links a {
  font-size: 13px;
  letter-spacing: 0.2em;
  color: var(--muted);
  transition: color 0.3s;
  position: relative;
}

.nav-links a:hover { color: var(--gold-bright); }

.nav-links a::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -6px;
  width: 0;
  height: 1px;
  background: var(--gold);
  transition: width 0.35s;
}

.nav-links a:hover::after { width: 100%; }

.btn {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 13px 30px;
  border: 1px solid var(--gold);
  color: var(--gold-bright);
  font-size: 13px;
  letter-spacing: 0.25em;
  transition: all 0.35s;
  background: transparent;
  cursor: pointer;
  font-family: var(--sans);
}

.btn:hover {
  background: var(--gold);
  color: var(--ink);
  box-shadow: 0 8px 30px rgba(201, 168, 106, 0.25);
}

.btn .arr { font-family: var(--latin); font-size: 15px; }

.hairline {
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--line), transparent);
  border: none;
}

.site-footer {
  border-top: 1px solid var(--line-soft);
  padding: 44px clamp(20px, 5vw, 64px) 40px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 20px;
  flex-wrap: wrap;
  background: var(--ink-2);
}

.site-footer .f-mark {
  font-family: var(--serif);
  letter-spacing: 0.3em;
  font-size: 15px;
  color: var(--paper-dim);
}

.site-footer .f-meta {
  font-size: 12px;
  letter-spacing: 0.15em;
  color: var(--dim);
}

.reveal {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity 0.9s cubic-bezier(0.22, 1, 0.36, 1), transform 0.9s cubic-bezier(0.22, 1, 0.36, 1);
}

.reveal.in { opacity: 1; transform: none; }

@media (max-width: 720px) {
  .nav-links a:not(.btn) { display: none; }
  .site-nav { padding: 16px 20px; }
}