:root {
  --color-surface: #f8f8f8;
  --color-surface-alt: #efeff0;
  --color-surface-deep: #e2e3e4;
  --color-ink: #434651;
  --color-ink-soft: #686e7d;
  --color-ink-muted: #757b8a;
  --color-line: #d7d8da;
  --color-primary: #4363bc;
  --color-primary-ink: #ffffff;
  --color-primary-soft: #dfe3f0;
  --color-accent: #117f88;
  --color-accent-ink: #ffffff;
  --color-highlight: #cee2e4;
  --color-focus: #097d86;
  --color-contrast-surface: #0f1118;
  --color-contrast-ink: #e4e5e7;
  --color-contrast-line: #3e4046;
  --color-contrast-accent: #1dd4e2;
  --overlay-scrim: linear-gradient(180deg, rgba(15, 17, 24, 0.35) 0%, rgba(15, 17, 24, 0.72) 55%, rgba(15, 17, 24, 0.92) 100%);
  --font-heading: "PingFang SC", "HarmonyOS Sans SC", "Microsoft YaHei", "Source Han Sans SC", sans-serif;
  --font-body: "PingFang SC", "HarmonyOS Sans SC", "Microsoft YaHei", "Source Han Sans SC", sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  --text-xs: 11.4px;
  --text-sm: 13.7px;
  --text-base: 15px;
  --text-lg: 18.0px;
  --text-xl: 21.6px;
  --text-2xl: 25.9px;
  --text-3xl: 31.1px;
  --text-4xl: 37.3px;
  --text-display: clamp(36px, 7.4vw, 95px);
  --text-figure: clamp(30px, 5.3vw, 68px);
  --weight-heading: 644;
  --weight-body: 400;
  --leading-body: 1.72;
  --leading-heading: 1.27;
  --tracking-heading: 0.005em;
  --radius-sm: 1px;
  --radius-md: 1px;
  --radius-lg: 1px;
  --radius-pill: 1px;
  --border-thin: 1px;
  --border-thick: 1px;
  --shadow-1: none;
  --shadow-2: none;
  --space-1: 7px;
  --space-2: 14px;
  --space-3: 21px;
  --space-4: 28px;
  --space-6: 42px;
  --space-8: 56px;
  --container: 1280px;
  --measure: 73ch;
  --gutter: 21px;
  --section-y: 84px;
  --section-y-lg: 118px;
}

/* ============ 1. Reset ============ */
*,
*::before,
*::after { box-sizing: border-box; }

html {
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: 110px;
}

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

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

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

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

button {
  font: inherit;
  color: inherit;
  background: none;
  border: 0;
  padding: 0;
  cursor: pointer;
}

table {
  border-collapse: collapse;
  width: 100%;
}

hr {
  border: 0;
  border-top: var(--border-thin) solid var(--color-line);
  margin: 0;
}

/* ============ 2. 蓝图底：冷调坐标网格 ============ */
body {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  font-family: var(--font-body);
  font-size: var(--text-base);
  font-weight: var(--weight-body);
  line-height: var(--leading-body);
  color: var(--color-ink);
  background-color: var(--color-surface);
  background-image:
    linear-gradient(to right, color-mix(in srgb, var(--color-line) 58%, transparent) 1px, transparent 1px),
    linear-gradient(to bottom, color-mix(in srgb, var(--color-line) 58%, transparent) 1px, transparent 1px);
  background-size: 84px 84px;
  background-position: center top;
  font-variant-numeric: tabular-nums;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

body.nav-open { overflow: hidden; }

/* ============ 3. 中文排版 ============ */
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);
  color: var(--color-ink);
  text-wrap: balance;
}

h1 { font-size: var(--text-3xl); }
h2 { font-size: var(--text-2xl); }
h3 { font-size: var(--text-xl); }
h4 { font-size: var(--text-lg); }
h5 { font-size: var(--text-base); }
h6 { font-size: var(--text-sm); }

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

strong { font-weight: var(--weight-heading); }

.mono {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.07em;
  font-variant-numeric: tabular-nums;
}

.eyebrow {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.16em;
  color: var(--color-primary);
  text-transform: uppercase;
  max-width: none;
}

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

:focus:not(:focus-visible) { outline: none; }

/* ============ 4. 布局骨架 ============ */
.site-main {
  display: block;
  flex: 1 1 auto;
  min-width: 0;
}

.shell {
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: var(--space-6);
}

.section {
  position: relative;
  padding-block: var(--section-y);
}

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

.section--dark {
  background-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
}

.section--dark h1,
.section--dark h2,
.section--dark h3,
.section--dark h4 { color: var(--color-contrast-ink); }

.section--dark p { color: var(--color-contrast-ink); }

.section--dark .eyebrow { color: var(--color-contrast-accent); }

.section--dark hr,
.section--dark .section-head { border-color: var(--color-contrast-line); }

.section-head {
  display: grid;
  gap: var(--space-2);
  margin-bottom: var(--space-6);
  padding-top: var(--space-3);
  border-top: var(--border-thin) solid var(--color-line);
}

.section--dark .section-head { border-top-color: var(--color-contrast-line); }

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

/* ============ 5. 跳转链接 ============ */
.skip-link {
  position: fixed;
  left: var(--space-4);
  top: -120px;
  z-index: 300;
  display: inline-block;
  padding: var(--space-2) var(--space-3);
  background-color: var(--color-primary);
  color: var(--color-primary-ink);
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  font-weight: var(--weight-heading);
  border-radius: var(--radius-sm);
  transition: top 0.16s ease;
}

.skip-link:focus {
  top: var(--space-3);
  outline: 2px solid var(--color-focus);
  outline-offset: 2px;
}

/* ============ 6. 页眉：框架式导航 ============ */
.site-header {
  position: sticky;
  top: 0;
  z-index: 90;
  background-color: var(--color-surface);
  border-bottom: var(--border-thin) solid var(--color-line);
  transition: border-color 0.2s ease;
}

.site-header.is-scrolled {
  border-bottom-color: color-mix(in srgb, var(--color-primary) 50%, var(--color-line));
}

.header-ruler {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  max-width: var(--container);
  margin-inline: auto;
  padding: var(--space-1) var(--space-6) 0;
  height: 22px;
}

.ruler-label {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.1em;
  color: var(--color-ink-muted);
  white-space: nowrap;
}

.ruler-ticks {
  flex: 1 1 auto;
  height: 6px;
  min-width: 40px;
  background-image: repeating-linear-gradient(
    to right,
    var(--color-line) 0 1px,
    transparent 1px 7px
  );
  background-repeat: repeat-x;
  background-size: auto 6px;
}

.header-bar {
  display: flex;
  align-items: center;
  gap: var(--space-4);
  max-width: var(--container);
  margin-inline: auto;
  padding: var(--space-2) var(--space-6);
  min-height: 64px;
}

/* 品牌 */
.brand {
  display: inline-flex;
  flex-direction: column;
  gap: 1px;
  padding-left: var(--space-2);
  border-left: 2px solid var(--color-primary);
  white-space: nowrap;
  min-width: 0;
}

.brand-name {
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-lg);
  line-height: 1.24;
  letter-spacing: 0.02em;
  color: var(--color-ink);
}

.brand-sub {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.04em;
  color: var(--color-ink-muted);
  line-height: 1.3;
}

.brand:hover .brand-name { color: var(--color-primary); }

/* 主导航 */
.site-nav {
  margin-left: auto;
  min-width: 0;
}

.nav-list {
  display: flex;
  align-items: stretch;
  flex-wrap: nowrap;
}

.nav-item { display: flex; }

.nav-link {
  display: inline-flex;
  align-items: center;
  height: 100%;
  padding: var(--space-2) var(--space-3);
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  font-weight: var(--weight-heading);
  letter-spacing: 0.02em;
  color: var(--color-ink-soft);
  border-left: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-sm);
  transition: color 0.16s ease, background-color 0.16s ease, border-color 0.16s ease;
  white-space: nowrap;
}

.nav-item:last-child .nav-link {
  border-right: var(--border-thin) solid var(--color-line);
}

.nav-link:hover {
  color: var(--color-primary);
  background-color: var(--color-primary-soft);
  border-color: var(--color-primary);
}

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

/* 刷新状态小块 */
.header-status {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  max-width: none;
  padding: var(--space-1) var(--space-2);
  border: var(--border-thin) solid color-mix(in srgb, var(--color-accent) 45%, var(--color-line));
  background-color: color-mix(in srgb, var(--color-highlight) 40%, transparent);
  color: var(--color-accent);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.06em;
  line-height: 1.3;
  white-space: nowrap;
  border-radius: var(--radius-sm);
}

.pulse-dot {
  width: 7px;
  height: 7px;
  flex: none;
  background-color: var(--color-accent);
  border-radius: var(--radius-sm);
  animation: ts-pulse 2.4s steps(1, end) infinite;
}

@keyframes ts-pulse {
  0%, 45% { background-color: var(--color-accent); }
  55%, 100% { background-color: var(--color-highlight); }
}

/* 移动导航按钮 */
.nav-toggle {
  display: none;
  align-items: center;
  gap: var(--space-1);
  margin-left: auto;
  padding: var(--space-1) var(--space-2);
  border: var(--border-thin) solid var(--color-line);
  background-color: var(--color-surface);
  color: var(--color-ink);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.08em;
  border-radius: var(--radius-sm);
  transition: background-color 0.16s ease, color 0.16s ease, border-color 0.16s ease;
}

.nav-toggle-bars {
  position: relative;
  width: 14px;
  height: 8px;
  flex: none;
}

.nav-toggle-bars::before,
.nav-toggle-bars::after {
  content: "";
  position: absolute;
  left: 0;
  width: 100%;
  height: 1px;
  background-color: currentColor;
}

.nav-toggle-bars::before { top: 0; }
.nav-toggle-bars::after { bottom: 0; }

.nav-toggle:hover { border-color: var(--color-primary); color: var(--color-primary); }

.nav-toggle[aria-expanded="true"] {
  background-color: var(--color-primary);
  border-color: var(--color-primary);
  color: var(--color-primary-ink);
}

/* 滚动进度 */
.scroll-progress {
  height: 2px;
  background-color: color-mix(in srgb, var(--color-line) 70%, transparent);
}

.scroll-progress > span {
  display: block;
  height: 100%;
  width: 100%;
  background-color: var(--color-accent);
  transform: scaleX(0);
  transform-origin: 0 50%;
  transition: transform 0.1s linear;
}

/* ============ 7. 页脚：边框式图签栏 ============ */
.site-footer {
  margin-top: auto;
  background-color: var(--color-surface-alt);
  border-top: var(--border-thin) solid var(--color-line);
}

.footer-ruler {
  position: relative;
  height: 15px;
  border-bottom: var(--border-thin) dotted var(--color-line);
}

.footer-ruler::before {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 6px;
  background-image: repeating-linear-gradient(
    to right,
    var(--color-line) 0 1px,
    transparent 1px 14px
  );
  background-repeat: repeat-x;
}

.footer-main {
  display: grid;
  grid-template-columns: minmax(0, 1.7fr) minmax(0, 1.3fr) minmax(0, 1fr);
  gap: var(--space-6);
  max-width: var(--container);
  margin-inline: auto;
  padding: var(--space-8) var(--space-6) var(--space-6);
}

.footer-brand {
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-xl);
  line-height: var(--leading-heading);
  color: var(--color-ink);
  padding-left: var(--space-2);
  border-left: 2px solid var(--color-primary);
  margin-bottom: var(--space-2);
  max-width: none;
}

.footer-line {
  font-size: var(--text-sm);
  line-height: 1.6;
  color: var(--color-ink-soft);
  max-width: 42ch;
}

.footer-line.mono {
  font-size: var(--text-xs);
  letter-spacing: 0.06em;
  color: var(--color-ink-muted);
  margin-bottom: var(--space-1);
}

.footer-contact {
  display: grid;
  gap: var(--space-2);
  align-content: start;
}

.footer-contact-row {
  display: grid;
  grid-template-columns: 84px minmax(0, 1fr);
  gap: var(--space-2);
  align-items: baseline;
  padding-bottom: var(--space-2);
  border-bottom: var(--border-thin) dotted var(--color-line);
}

.footer-contact-row dt {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.06em;
  color: var(--color-ink-muted);
}

.footer-contact-row dd {
  font-size: var(--text-sm);
  color: var(--color-ink);
  word-break: break-all;
}

.footer-terms-title {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.12em;
  color: var(--color-ink-muted);
  padding-bottom: var(--space-2);
  margin-bottom: var(--space-2);
  border-bottom: var(--border-thin) solid var(--color-line);
  max-width: none;
}

.footer-terms ul {
  display: grid;
  gap: var(--space-1);
}

.footer-terms a {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  padding: 2px 0;
  font-size: var(--text-sm);
  color: var(--color-ink);
  border-bottom: var(--border-thin) solid transparent;
  transition: color 0.16s ease, border-color 0.16s ease;
}

.footer-terms a::before {
  content: "\2192";
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-primary);
}

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

.footer-base {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2) var(--space-4);
  justify-content: space-between;
  align-items: center;
  max-width: var(--container);
  margin-inline: auto;
  padding: var(--space-3) var(--space-6);
  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);
}

/* ============ 8. 通用组件 ============ */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  padding: var(--space-2) var(--space-4);
  border: var(--border-thin) solid var(--color-primary);
  background-color: var(--color-primary);
  color: var(--color-primary-ink);
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  font-weight: var(--weight-heading);
  letter-spacing: 0.03em;
  line-height: 1.4;
  border-radius: var(--radius-sm);
  text-align: center;
  transition: background-color 0.16s ease, color 0.16s ease;
}

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

.btn--ghost {
  background-color: transparent;
  color: var(--color-primary);
}

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

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

.btn--accent:hover {
  background-color: transparent;
  color: var(--color-accent);
}

.section--dark .btn {
  border-color: var(--color-contrast-accent);
  background-color: var(--color-contrast-accent);
  color: var(--color-contrast-surface);
}

.section--dark .btn:hover {
  background-color: transparent;
  color: var(--color-contrast-accent);
}

.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);
  padding-bottom: var(--space-3);
}

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

.crumbs li + li::before {
  content: "/";
  color: var(--color-line);
}

.crumbs a { color: var(--color-ink-soft); }
.crumbs a:hover { color: var(--color-primary); }
.crumbs [aria-current="page"] { color: var(--color-ink); }

.tag {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  padding: 2px var(--space-2);
  border: var(--border-thin) solid var(--color-line);
  background-color: var(--color-surface-alt);
  color: var(--color-ink-soft);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.06em;
  line-height: 1.5;
  border-radius: var(--radius-sm);
  white-space: nowrap;
}

.tag--primary {
  background-color: var(--color-primary);
  border-color: var(--color-primary);
  color: var(--color-primary-ink);
}

.tag--accent {
  background-color: var(--color-accent);
  border-color: var(--color-accent);
  color: var(--color-accent-ink);
}

.card {
  display: grid;
  gap: var(--space-2);
  align-content: start;
  padding: var(--space-4);
  border: var(--border-thin) solid var(--color-line);
  background-color: var(--color-surface);
  border-radius: var(--radius-sm);
  transition: border-color 0.16s ease, transform 0.16s ease, background-color 0.16s ease;
}

.card:hover {
  border-color: var(--color-primary);
  transform: translateY(-2px);
}

.card > :last-child { margin-bottom: 0; }

.section--dark .card {
  background-color: color-mix(in srgb, var(--color-contrast-ink) 6%, var(--color-contrast-surface));
  border-color: var(--color-contrast-line);
}

.section--dark .card:hover { border-color: var(--color-contrast-accent); transform: none; }

.figure {
  font-family: var(--font-mono);
  font-size: var(--text-figure);
  font-weight: var(--weight-heading);
  line-height: 0.98;
  letter-spacing: -0.02em;
  color: var(--color-ink);
  font-variant-numeric: tabular-nums;
  max-width: none;
}

.figure--key {
  background-color: var(--color-highlight);
  padding: 0 var(--space-1);
}

.section--dark .figure { color: var(--color-contrast-ink); }

.section--dark .figure--key {
  background-color: transparent;
  color: var(--color-contrast-accent);
  padding: 0;
}

/* 图片容器基础规则：统一 3:2 裁切 + 1px 描边，图上压字必须叠 --overlay-scrim */
.frame {
  position: relative;
  display: block;
  overflow: hidden;
  aspect-ratio: 3 / 2;
  border: var(--border-thin) solid var(--color-line);
  background-color: var(--color-surface-deep);
  border-radius: var(--radius-sm);
}

.frame > img,
.frame > video,
.frame > .frame-media {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.frame--video { aspect-ratio: 16 / 9; }
.frame--square { aspect-ratio: 1 / 1; }
.frame--tall { aspect-ratio: 4 / 5; }

.frame-overlay {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  justify-content: flex-end;
  gap: var(--space-1);
  padding: var(--space-3);
  background: var(--overlay-scrim);
  color: var(--color-contrast-ink);
}

.frame-overlay p,
.frame-overlay h3,
.frame-overlay h4 { color: var(--color-contrast-ink); max-width: none; }

.frame-caption {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: var(--space-2);
  padding-top: var(--space-1);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.06em;
  color: var(--color-ink-muted);
  max-width: none;
}

/* ============ 9. 响应式 ============ */
@media (max-width: 1023px) {
  .footer-main {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
    gap: var(--space-4) var(--space-6);
  }

  .footer-terms { grid-column: 1 / -1; }
}

@media (max-width: 899px) {
  .header-bar {
    padding-block: var(--space-2);
    gap: var(--space-3);
  }

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

  .header-status { display: none; }

  .site-nav {
    display: none;
    position: absolute;
    left: 0;
    right: 0;
    top: 100%;
    margin-left: 0;
    background-color: var(--color-surface);
    border-top: var(--border-thin) solid var(--color-line);
    border-bottom: 2px solid var(--color-primary);
    max-height: calc(100vh - 120px);
    overflow-y: auto;
  }

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

  .nav-list {
    flex-direction: column;
    align-items: stretch;
  }

  .nav-item { display: block; }

  .nav-link {
    width: 100%;
    height: auto;
    padding: var(--space-3) var(--space-6);
    border-left: 0;
    border-top: var(--border-thin) dotted var(--color-line);
    border-radius: 0;
    font-size: var(--text-base);
  }

  .nav-item:first-child .nav-link { border-top: 0; }

  .nav-item:last-child .nav-link { border-right: 0; }

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

  .ruler-label:first-child { display: none; }
}

@media (max-width: 767px) {
  .section { padding-block: var(--space-8); }
  .section--lg { padding-block: var(--space-8); }

  .footer-main {
    grid-template-columns: minmax(0, 1fr);
    gap: var(--space-4);
  }

  .footer-terms { grid-column: auto; }
}

@media (max-width: 639px) {
  .shell { padding-inline: var(--space-4); }

  .header-ruler { padding-inline: var(--space-4); }

  .header-bar { padding-inline: var(--space-4); }

  .brand-sub { display: none; }

  .brand-name { font-size: var(--text-base); }

  .nav-link { padding-inline: var(--space-4); }

  .footer-main { padding: var(--space-6) var(--space-4) var(--space-4); }

  .footer-base { padding-inline: var(--space-4); }

  .footer-contact-row {
    grid-template-columns: minmax(0, 1fr);
    gap: 2px;
  }

  .figure { font-size: var(--text-3xl); }

  .frame-overlay { padding: var(--space-2); }
}

/* ============ 10. 减弱动效 ============ */
@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;
    scroll-behavior: auto !important;
  }

  .pulse-dot {
    animation: none;
    background-color: var(--color-accent);
  }

  .card:hover { transform: none; }

  .skip-link { transition: none; }

  .scroll-progress > span { transition: none; }
}