/* 令牌、重置、通用排版、页头 */
:root {
  color-scheme: dark;
  --night: oklch(0.055 0 0);
  --night-raised: oklch(0.12 0 0);
  --night-ink: oklch(0.97 0 0);
  --night-muted: oklch(0.7 0.008 356.8);
  --stage: oklch(0.075 0 0);
  --stage-ink: oklch(0.97 0 0);
  --stage-muted: oklch(0.67 0.008 356.8);
  --chapter-subtitle-ink: oklch(0.88 0.006 356.8);
  --dot: oklch(0.8 0.01 356.8 / 0.2);
  --rose: oklch(0.734 0.183 356.8);
  --cyan: oklch(0.82 0.14 195);
  --danger: oklch(0.68 0.2 25);
  --folder-back: oklch(0.255 0.014 356.8);
  --folder-front-top: oklch(0.225 0.013 356.8);
  --folder-front-bottom: oklch(0.175 0.01 356.8);
  --folder-edge: oklch(0.48 0.016 356.8);
  --folder-highlight: oklch(0.72 0.012 356.8);
  --folder-shadow: oklch(0.015 0 0 / 0.82);
  --ease-out: cubic-bezier(0.22, 1, 0.36, 1);
  --z-header: 10;
  --z-backdrop: 20;
  --z-modal: 30;
  --font-display: Futura, "Avenir Next", "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", sans-serif;
  --font-copy: "Avenir Next", "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", sans-serif;
  --type-hero: clamp(3.6rem, 6.4vw, 6rem);
  --type-page: clamp(3.2rem, 7vw, 6rem);
  --type-section: clamp(2.75rem, 5vw, 4.5rem);
  --type-feature: clamp(1.7rem, 3vw, 3.2rem);
  --type-title: clamp(1.23rem, 2.125vw, 1.83rem);
  --type-subtitle: clamp(1rem, 1.4vw, 1.25rem);
  --type-body: clamp(0.875rem, 1.05vw, 1rem);
  --type-small: clamp(0.75rem, 0.85vw, 0.84rem);
  --type-eyebrow: clamp(0.7rem, 0.78vw, 0.78rem);
  --weight-display: 500;
  --weight-copy: 500;
  --leading-display: 0.92;
  --leading-title: 1.05;
  --leading-copy: 1.55;
  --tracking-subtitle: -0.018em;
  --tracking-copy: -0.01em;
  font-family: var(--font-copy);
  font-weight: var(--weight-copy);
  font-synthesis: none;
  font-kerning: normal;
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }
body {
  margin: 0;
  min-width: 320px;
  min-height: 100vh;
  overflow-x: hidden;
  background-color: var(--night);
  background-image: radial-gradient(circle, var(--dot) 0.8px, transparent 0.95px);
  background-size: 21px 21px;
  color: var(--night-ink);
  font-family: var(--font-copy);
  line-height: var(--leading-copy);
}

button, a { font: inherit; -webkit-tap-highlight-color: transparent; }
button { color: inherit; }
h1, h2, h3 { font-family: var(--font-display); font-weight: var(--weight-display); }
:where(main, h1)[tabindex="-1"]:focus { outline: none; }
.chapter-subtitle {
  color: var(--chapter-subtitle-ink);
  font-family: var(--font-copy);
  font-size: var(--type-subtitle);
  font-weight: var(--weight-copy);
  line-height: var(--leading-copy);
  letter-spacing: var(--tracking-subtitle);
  text-wrap: balance;
}
:where(button, a):focus-visible {
  outline: none;
  box-shadow: none;
}

.skip-link {
  position: fixed;
  z-index: calc(var(--z-modal) + 1);
  top: 10px;
  left: 10px;
  padding: 10px 14px;
  border-radius: 999px;
  background: var(--night-ink);
  color: var(--night);
  transform: translateY(-160%);
  transition: transform 180ms var(--ease-out);
}

.night-glow {
  position: fixed;
  inset: 0;
  pointer-events: none;
  background:
    radial-gradient(46rem 38rem at 18% 14%, oklch(0.734 0.183 356.8 / 0.05), transparent 72%),
    radial-gradient(38rem 34rem at 84% 72%, oklch(0.82 0.14 195 / 0.03), transparent 74%);
}

.site-header {
  position: fixed;
  z-index: var(--z-header);
  top: 0;
  left: 0;
  right: 0;
  min-height: 72px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: max(12px, env(safe-area-inset-top)) max(clamp(18px, 3vw, 46px), env(safe-area-inset-right)) 12px max(clamp(18px, 3vw, 46px), env(safe-area-inset-left));
  pointer-events: none;
}

.site-signature, .gallery-back { pointer-events: auto; }
.site-signature { display: inline-flex; align-items: center; gap: 10px; color: var(--night-ink); text-decoration: none; }
.site-signature img { width: 25px; height: 28px; object-fit: contain; filter: invert(1); }
.site-signature span { font-size: var(--type-small); font-weight: 650; letter-spacing: -0.02em; }

.gallery-back {
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 0 18px;
  border: 1px solid oklch(1 0 0 / 0.14);
  border-radius: 999px;
  background: oklch(0.17 0.012 356.8 / 0.92);
  color: var(--night-ink);
  cursor: pointer;
  box-shadow: 0 2px 6px oklch(0 0 0 / 0.4);
  backdrop-filter: blur(6px);
  transition: background 180ms var(--ease-out), border-color 180ms var(--ease-out), transform 180ms var(--ease-out);
}
.gallery-back:hover { background: oklch(0.22 0.015 356.8); border-color: oklch(1 0 0 / 0.26); transform: translateY(-1px); }
.gallery-back:active { transform: scale(0.97); }

.image-placeholder {
  position: absolute;
  z-index: 2;
  inset: 0;
  display: block;
  width: 100%;
  height: 100%;
  border-radius: inherit;
  background:
    radial-gradient(circle at 24% 28%, oklch(0.27 0.018 356.8), transparent 38%),
    linear-gradient(145deg, oklch(0.16 0.007 356.8), oklch(0.095 0.004 356.8));
  opacity: 0;
  pointer-events: none;
}
.image-placeholder.is-visible { opacity: 1; }
.image-placeholder.is-hiding { opacity: 0; filter: blur(1.2px); transition: opacity 150ms var(--ease-out), filter 150ms var(--ease-out); }
.image-placeholder[data-has-thumbhash="false"] { image-rendering: auto; }
.image-placeholder[data-has-thumbhash="true"] { background: transparent; }
.image-load-sweep {
  position: absolute;
  z-index: 3;
  top: -12%;
  bottom: -12%;
  left: -22%;
  width: 13%;
  background: linear-gradient(90deg, transparent, oklch(1 0 0 / 0.13) 44%, oklch(0.78 0.09 356.8 / 0.1) 54%, transparent);
  filter: blur(7px);
  opacity: 0;
  transform: translate3d(-150%, 0, 0) skewX(-9deg);
  pointer-events: none;
}
.image-load-sweep.is-sweep-a { animation: image-sweep-a 2400ms linear infinite; }
.image-load-sweep.is-sweep-b { animation: image-sweep-b 2400ms linear infinite; }
@keyframes image-sweep-a {
  0% { opacity: 0; transform: translate3d(-150%, 0, 0) skewX(-9deg); }
  8% { opacity: 0.78; }
  40% { opacity: 0.46; }
  50%, 100% { opacity: 0; transform: translate3d(950%, 0, 0) skewX(-9deg); }
}
@keyframes image-sweep-b {
  0% { opacity: 0; transform: translate3d(-150%, 0, 0) skewX(-9deg); }
  8% { opacity: 0.78; }
  40% { opacity: 0.46; }
  50%, 100% { opacity: 0; transform: translate3d(950%, 0, 0) skewX(-9deg); }
}

@media (max-width: 760px) {
  .site-header { min-height: 64px; }
}

@media (min-width: 761px) and (prefers-reduced-motion: no-preference) {
  html {
    overscroll-behavior-y: none;
  }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation-duration: 0.01ms !important; animation-iteration-count: 1 !important; transition-duration: 0.01ms !important; }
  .image-load-sweep { display: none; }
}