:root {
  --color-surface: #151515;
  --color-surface-alt: #262626;
  --color-surface-deep: #3a3b3b;
  --color-ink: #ced5d3;
  --color-ink-soft: #8a9995;
  --color-ink-muted: #788783;
  --color-line: #363837;
  --color-primary: #2ad5a9;
  --color-primary-ink: #111816;
  --color-primary-soft: #18302a;
  --color-accent: #21deae;
  --color-accent-ink: #111816;
  --color-highlight: #173931;
  --color-focus: #14ebb4;
  --color-contrast-surface: #f5f6f6;
  --color-contrast-ink: #333837;
  --color-contrast-line: #cacccc;
  --color-contrast-accent: #127c61;
  --overlay-scrim: linear-gradient(180deg, rgba(245, 246, 246, 0.35) 0%, rgba(245, 246, 246, 0.72) 55%, rgba(245, 246, 246, 0.92) 100%);
  --font-heading: ui-monospace, SFMono-Regular, Menlo, Consolas, "PingFang SC", monospace;
  --font-body: "PingFang SC", "Microsoft YaHei", "Source Han Sans SC", sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  --text-xs: 11.4px;
  --text-sm: 14.3px;
  --text-base: 16px;
  --text-lg: 20.0px;
  --text-xl: 25.0px;
  --text-2xl: 31.2px;
  --text-3xl: 39.1px;
  --text-4xl: 48.8px;
  --text-display: clamp(45px, 9.3vw, 119px);
  --text-figure: clamp(38px, 6.7vw, 86px);
  --weight-heading: 641;
  --weight-body: 400;
  --leading-body: 1.65;
  --leading-heading: 1.24;
  --tracking-heading: 0.005em;
  --radius-sm: 2px;
  --radius-md: 3px;
  --radius-lg: 4px;
  --radius-pill: 4px;
  --border-thin: 1px;
  --border-thick: 1px;
  --shadow-1: none;
  --shadow-2: none;
  --space-1: 6px;
  --space-2: 12px;
  --space-3: 18px;
  --space-4: 24px;
  --space-6: 36px;
  --space-8: 48px;
  --container: 1340px;
  --measure: 67ch;
  --gutter: 24px;
  --section-y: 79px;
  --section-y-lg: 111px;
}

/* ---------- reset ---------- */
*,
*::before,
*::after { box-sizing: border-box; }

body, h1, h2, h3, h4, h5, h6, p, ul, ol, dl, dd, figure, blockquote, pre {
  margin: 0;
}

ul, ol { padding: 0; list-style: none; }

img, svg, video { display: block; max-width: 100%; height: auto; }

button, input, select, textarea { font: inherit; color: inherit; }

html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }

/* ---------- base ---------- */
body {
  background-color: var(--color-surface);
  color: var(--color-ink);
  font-family: var(--font-body);
  font-size: var(--text-base);
  font-weight: var(--weight-body);
  line-height: var(--leading-body);
  overflow-wrap: break-word;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

body::after {
  content: "";
  position: fixed;
  inset: 0;
  z-index: 9999;
  pointer-events: none;
  background-image: repeating-linear-gradient(
    180deg,
    rgba(206, 213, 211, 0.03) 0 1px,
    transparent 1px 4px
  );
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  line-height: var(--leading-heading);
  letter-spacing: var(--tracking-heading);
}

p { max-width: var(--measure); }

a { color: inherit; text-decoration: none; }

strong, b { font-weight: 700; }

::selection {
  background-color: var(--color-primary);
  color: var(--color-primary-ink);
}

:focus-visible {
  outline: 2px solid var(--color-focus);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
}

/* ---------- layout ---------- */
.sk-container {
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.section { padding-block: var(--section-y); }
.section--lg { padding-block: var(--section-y-lg); }
.section--tight { padding-block: var(--space-6); }

.grid-12 {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  gap: var(--gutter);
  align-items: start;
}

.col-main { grid-column: span 8; min-width: 0; }
.col-aside { grid-column: span 4; min-width: 0; }

.stack > * + * { margin-top: var(--space-3); }
.stack--loose > * + * { margin-top: var(--space-6); }

.prose { max-width: var(--measure); }
.prose > * + * { margin-top: var(--space-3); }

/* ---------- utilities ---------- */
.mono {
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  letter-spacing: 0.02em;
}

.muted { color: var(--color-ink-muted); }

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.14em;
  color: var(--color-ink-muted);
  text-transform: uppercase;
}

.figure-num {
  font-family: var(--font-mono);
  font-size: var(--text-figure);
  font-weight: 800;
  line-height: 1;
  color: var(--color-primary);
  border-bottom: 2px solid var(--color-accent);
  padding-bottom: var(--space-1);
  display: inline-block;
}

.divider {
  height: 0;
  border: 0;
  border-top: var(--border-thin) dotted var(--color-line);
  margin-block: var(--space-4);
}

.skip-link {
  position: absolute;
  top: -120px;
  left: var(--space-4);
  z-index: 300;
  padding: var(--space-2) var(--space-4);
  background-color: var(--color-primary);
  color: var(--color-primary-ink);
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  border-radius: var(--radius-sm);
  transition: top 0.18s ease;
}

.skip-link:focus { top: var(--space-3); }

.status-dot {
  display: inline-block;
  flex: 0 0 auto;
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background-color: var(--color-primary);
  box-shadow: 0 0 0 3px color-mix(in srgb, var(--color-primary) 24%, transparent);
  animation: cs-pulse 2.4s ease-in-out infinite;
}

@keyframes cs-pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.3; }
}

/* ---------- buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-4);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-sm);
  background-color: transparent;
  color: var(--color-ink);
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  letter-spacing: 0.02em;
  cursor: pointer;
  transition: background-color 0.16s ease, color 0.16s ease, border-color 0.16s ease;
}

.btn:hover {
  background-color: var(--color-highlight);
  border-color: var(--color-primary);
  color: var(--color-primary);
}

.btn--primary {
  background-color: var(--color-primary);
  border-color: var(--color-primary);
  color: var(--color-primary-ink);
  font-weight: 700;
}

.btn--primary:hover {
  background-color: var(--color-accent);
  border-color: var(--color-accent);
  color: var(--color-accent-ink);
}

.btn--line {
  border-style: dotted;
  border-color: var(--color-line);
  color: var(--color-ink-soft);
}

.btn--line:hover { color: var(--color-primary); border-color: var(--color-primary); }

/* ---------- tag ---------- */
.tag {
  display: inline-flex;
  align-items: center;
  padding: 2px var(--space-2);
  border: var(--border-thin) dotted var(--color-line);
  border-radius: var(--radius-sm);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.06em;
  color: var(--color-ink-soft);
  white-space: nowrap;
}

.tag.is-on {
  border-color: var(--color-primary);
  background-color: var(--color-primary-soft);
  color: var(--color-primary);
}

/* ---------- breadcrumb ---------- */
.crumbs {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-2);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.06em;
  color: var(--color-ink-muted);
}

.crumbs a { color: var(--color-ink-soft); }
.crumbs a:hover { color: var(--color-primary); }
.crumbs__sep { color: var(--color-line); }

/* ---------- index rail ---------- */
.idx-rail {
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  border-top: var(--border-thin) dotted var(--color-line);
}

.idx-rail__item {
  display: flex;
  align-items: baseline;
  gap: var(--space-3);
  padding-block: var(--space-2);
  border-bottom: var(--border-thin) dotted var(--color-line);
  color: var(--color-ink-soft);
}

.idx-rail__num {
  flex: 0 0 auto;
  color: var(--color-ink-muted);
  font-size: var(--text-xs);
  letter-spacing: 0.12em;
}

.idx-rail__item.is-on .idx-rail__num { color: var(--color-primary); }
.idx-rail__item.is-on { color: var(--color-ink); }

/* ---------- panel ---------- */
.panel {
  background-color: var(--color-surface-alt);
  border: var(--border-thin) dotted var(--color-line);
  border-radius: var(--radius-md);
  padding: var(--space-4);
}

.panel__head {
  display: flex;
  align-items: baseline;
  gap: var(--space-2);
  margin-bottom: var(--space-3);
  padding-bottom: var(--space-2);
  border-bottom: var(--border-thin) dotted var(--color-line);
}

.panel__idx {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.12em;
  color: var(--color-ink-muted);
}

.panel__title {
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  font-weight: var(--weight-heading);
  color: var(--color-ink);
}

.panel__body { font-size: var(--text-base); color: var(--color-ink-soft); }

/* ---------- light block ---------- */
.light-block {
  background-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  border-radius: var(--radius-md);
  padding: var(--space-4);
}

.light-block h2,
.light-block h3 { color: var(--color-contrast-ink); }

.light-block a {
  color: var(--color-contrast-accent);
  border-bottom: var(--border-thin) dotted var(--color-contrast-line);
}

.light-block .divider { border-top-color: var(--color-contrast-line); }

.light-block__key {
  font-family: var(--font-mono);
  font-weight: 800;
  color: var(--color-contrast-accent);
}

/* ---------- figure ---------- */
.figure-frame {
  position: relative;
  overflow: hidden;
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-md);
  background-color: var(--color-surface-alt);
}

.figure-frame img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.figure-frame::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background-image: repeating-linear-gradient(
    180deg,
    rgba(17, 24, 22, 0.16) 0 1px,
    transparent 1px 3px
  );
  opacity: 0.5;
}

.figure-frame--wide { aspect-ratio: 16 / 9; }
.figure-frame--tall { aspect-ratio: 2 / 3; }
.figure-frame--square { aspect-ratio: 1 / 1; }
.figure-frame--portrait { aspect-ratio: 3 / 4; }

.figure-frame.is-overlay::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 1;
  background: var(--overlay-scrim);
}

.figure-frame__caption {
  position: absolute;
  left: var(--space-3);
  right: var(--space-3);
  bottom: var(--space-3);
  z-index: 2;
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  letter-spacing: 0.02em;
  color: var(--color-contrast-ink);
}

/* ---------- tabs ---------- */
.tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 2px;
  border-bottom: var(--border-thin) dotted var(--color-line);
}

.tab {
  appearance: none;
  border: 0;
  border-bottom: 2px solid transparent;
  background-color: transparent;
  padding: var(--space-2) var(--space-3);
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  letter-spacing: 0.02em;
  color: var(--color-ink-soft);
  cursor: pointer;
  transition: color 0.12s ease, background-color 0.12s ease, border-color 0.12s ease;
}

.tab:hover { color: var(--color-ink); background-color: var(--color-highlight); }

.tab[aria-selected="true"] {
  color: var(--color-primary);
  background-color: var(--color-primary-soft);
  border-bottom-color: var(--color-accent);
}

.tabpanel { padding-top: var(--space-4); }
.tabpanel[hidden] { display: none; }

/* ---------- header ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background-color: var(--color-surface);
  border-bottom: var(--border-thin) solid var(--color-line);
}

.hdr-top {
  background-color: var(--color-surface-alt);
  border-bottom: var(--border-thin) dotted var(--color-line);
}

.hdr-top__inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-2) var(--space-4);
  padding-block: var(--space-2);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.06em;
}

.hdr-brand {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  flex-wrap: wrap;
  max-width: none;
}

.hdr-brand__mark {
  display: inline-grid;
  place-items: center;
  width: 22px;
  height: 22px;
  border: var(--border-thin) solid var(--color-primary);
  border-radius: var(--radius-sm);
  color: var(--color-primary);
  font-size: var(--text-xs);
  font-weight: 700;
  letter-spacing: 0;
}

.hdr-brand__name {
  color: var(--color-ink);
  font-weight: 700;
  letter-spacing: 0.08em;
}

.hdr-brand__note { color: var(--color-ink-muted); }

.hdr-status {
  display: inline-flex;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--space-2);
  max-width: none;
  color: var(--color-ink-soft);
}

.hdr-status__sep { color: var(--color-line); }

.hdr-call {
  margin-left: auto;
  padding: 4px var(--space-3);
  border: var(--border-thin) solid var(--color-primary);
  border-radius: var(--radius-sm);
  color: var(--color-primary);
  white-space: nowrap;
  transition: background-color 0.16s ease, color 0.16s ease;
}

.hdr-call:hover {
  background-color: var(--color-primary);
  color: var(--color-primary-ink);
}

.hdr-bar { position: relative; }

.hdr-bar__inner {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  min-height: 54px;
}

.site-nav { flex: 1 1 auto; min-width: 0; }

.nav-list {
  display: flex;
  align-items: center;
  gap: 2px;
  overflow-x: auto;
  scroll-snap-type: x proximity;
  scrollbar-width: none;
  padding-block: var(--space-2);
}

.nav-list::-webkit-scrollbar { display: none; }

.nav-item { scroll-snap-align: start; flex: 0 0 auto; }

.nav-link {
  display: inline-block;
  padding: var(--space-2) var(--space-3);
  border-bottom: 2px solid transparent;
  border-radius: var(--radius-sm) var(--radius-sm) 0 0;
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  letter-spacing: 0.06em;
  color: var(--color-ink-soft);
  white-space: nowrap;
  transition: color 0.12s ease, background-color 0.12s ease, border-color 0.12s ease;
}

.nav-link:hover {
  color: var(--color-ink);
  background-color: var(--color-highlight);
}

.nav-link[aria-current="page"] {
  color: var(--color-primary);
  background-color: var(--color-primary-soft);
  border-bottom-color: var(--color-accent);
}

.nav-toggle {
  display: none;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-3);
  border: var(--border-thin) dotted var(--color-line);
  border-radius: var(--radius-sm);
  background-color: transparent;
  color: var(--color-ink);
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  cursor: pointer;
}

.nav-toggle__bars {
  display: inline-flex;
  flex-direction: column;
  gap: 3px;
  width: 14px;
}

.nav-toggle__bars i {
  display: block;
  height: 1px;
  background-color: var(--color-primary);
}

.nav-toggle__text { letter-spacing: 0.08em; }

.hdr-progress {
  height: 2px;
  background-color: var(--color-line);
}

.hdr-progress__bar {
  display: block;
  width: 0;
  height: 100%;
  background-color: var(--color-primary);
  transition: width 0.12s linear;
}

/* ---------- footer ---------- */
.site-footer {
  margin-top: var(--section-y-lg);
  padding-block: var(--space-8) var(--space-6);
  background-color: var(--color-surface);
  border-top: var(--border-thin) dotted var(--color-line);
}

.ftr-coord {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  margin-bottom: var(--space-8);
  max-width: none;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.14em;
  color: var(--color-ink-muted);
}

.ftr-coord__line {
  flex: 1 1 auto;
  height: 1px;
  background-image: repeating-linear-gradient(
    90deg,
    var(--color-line) 0 4px,
    transparent 4px 10px
  );
}

.ftr-coord__label { white-space: nowrap; }

.ftr-grid {
  display: grid;
  grid-template-columns: 1.5fr 1fr 1fr 1.3fr;
  gap: var(--space-6) var(--gutter);
}

.ftr-brand__name {
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  font-weight: var(--weight-heading);
  color: var(--color-ink);
  letter-spacing: 0.04em;
}

.ftr-brand__tag {
  margin-top: var(--space-1);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.12em;
  color: var(--color-primary);
  max-width: none;
}

.ftr-brand__meta {
  margin-top: var(--space-3);
  font-size: var(--text-sm);
  line-height: var(--leading-body);
  color: var(--color-ink-muted);
  max-width: 32ch;
}

.ftr-title {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  font-weight: 700;
  letter-spacing: 0.16em;
  color: var(--color-ink-muted);
  margin-bottom: var(--space-3);
}

.ftr-list { display: grid; gap: var(--space-1); }

.ftr-list li {
  font-size: var(--text-sm);
  color: var(--color-ink-soft);
  line-height: var(--leading-body);
}

.ftr-list a {
  color: var(--color-ink-soft);
  border-bottom: var(--border-thin) dotted transparent;
  transition: color 0.12s ease, border-color 0.12s ease;
}

.ftr-list a:hover {
  color: var(--color-primary);
  border-bottom-color: var(--color-primary);
}

.ftr-list--contact li { color: var(--color-ink-soft); }

.ftr-bottom {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-2) var(--space-4);
  margin-top: var(--space-8);
  padding-top: var(--space-4);
  border-top: var(--border-thin) dotted var(--color-line);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.06em;
  color: var(--color-ink-muted);
}

.ftr-bottom p { max-width: none; }

.ftr-terms { display: inline-flex; align-items: center; gap: var(--space-2); }

.ftr-terms a {
  color: var(--color-ink-soft);
  border-bottom: var(--border-thin) dotted var(--color-line);
}

.ftr-terms a:hover { color: var(--color-primary); border-bottom-color: var(--color-primary); }

.ftr-terms__sep { color: var(--color-line); }

.ftr-legal { margin-left: auto; order: 3; }

.ftr-signoff { order: 2; color: var(--color-ink-muted); }

/* ---------- motion ---------- */
[data-reveal] {
  opacity: 0;
  transform: translateY(10px);
  transition: opacity 0.32s ease, transform 0.32s ease;
}

[data-reveal].is-in { opacity: 1; transform: none; }

.is-glitch { animation: cs-glitch 0.08s steps(2, end) 1; }

@keyframes cs-glitch {
  0% { transform: translateX(0); filter: none; }
  50% { transform: translateX(-1px); filter: hue-rotate(28deg) saturate(1.4); }
  100% { transform: translateX(0); filter: none; }
}

/* ---------- responsive ---------- */
@media (max-width: 1080px) {
  .ftr-grid { grid-template-columns: 1.4fr 1fr 1fr; }
  .ftr-brand { grid-column: 1 / -1; }
}

@media (max-width: 900px) {
  .col-main,
  .col-aside { grid-column: 1 / -1; }

  .grid-12 { grid-template-columns: repeat(6, minmax(0, 1fr)); }

  .hdr-bar__inner { flex-wrap: wrap; padding-block: var(--space-2); }

  .nav-toggle { display: inline-flex; }

  .site-nav {
    display: none;
    flex: 1 1 100%;
    width: 100%;
    border-top: var(--border-thin) dotted var(--color-line);
    margin-top: var(--space-2);
  }

  .site-nav[data-open] { display: block; }

  .nav-list {
    flex-direction: column;
    align-items: stretch;
    overflow-x: visible;
    padding-block: var(--space-2);
  }

  .nav-link {
    display: block;
    padding: var(--space-3);
    border-bottom: var(--border-thin) dotted var(--color-line);
    border-left: 2px solid transparent;
    border-radius: 0;
  }

  .nav-link[aria-current="page"] {
    border-bottom-color: var(--color-line);
    border-left-color: var(--color-accent);
  }

  .hdr-call { margin-left: 0; }
}

@media (max-width: 720px) {
  .ftr-grid { grid-template-columns: 1fr; gap: var(--space-6); }
  .ftr-coord__line { display: none; }
  .ftr-coord { justify-content: flex-start; }
  .ftr-legal { margin-left: 0; order: 4; }
}

@media (max-width: 560px) {
  :root { --gutter: 18px; }

  .grid-12 { grid-template-columns: repeat(2, minmax(0, 1fr)); }

  .hdr-top__inner { gap: var(--space-1) var(--space-3); }
  .hdr-brand__note { display: none; }

  .panel { padding: var(--space-3); }
  .light-block { padding: var(--space-3); }

  .skip-link { left: var(--space-2); }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }

  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
  }

  [data-reveal] { opacity: 1; transform: none; }
  .status-dot { animation: none; }
}