/* ==========================================================================
   3499开服 — /assets/site.css
   共享外壳：reset / 变量 / 蓝图网格 / 命令栏 / 页脚 / 通用组件
   ========================================================================== */

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

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

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

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

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

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

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

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

/* ---------- 变量 ---------- */
:root {
  --ink-950: #070A11;
  --ink-900: #0A0D16;
  --ink-800: #141926;
  --ink-700: #1D2434;
  --line: #232B3D;
  --paper: #ECE7DC;
  --mist: #9BA4B4;

  --violet: #8B5CF6;
  --cyan: #3FD8C8;
  --orange: #FF6A2B;
  --amber: #E9B44C;
  --moss: #7B9A6B;
  --clay: #C4694A;

  --font-data: "JetBrains Mono", "IBM Plex Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  --font-display: "Oswald", "Barlow Condensed", "Noto Sans SC", system-ui, sans-serif;
  --font-serif: "Noto Serif SC", "Source Han Serif SC", "Songti SC", Georgia, serif;
  --font-body: "Noto Sans SC", Inter, system-ui, -apple-system, "Segoe UI", sans-serif;

  --maxw: 1320px;
  --gutter: 24px;
  --bar-h: 56px;
  --radius: 4px;
  --hairline: 1px solid var(--line);
  --inset: inset 0 1px 0 rgba(236, 231, 220, 0.03);
  --ease: cubic-bezier(0.22, 0.61, 0.36, 1);
}

/* ---------- 基础排版 ---------- */
body {
  background-color: var(--ink-900);
  background-image:
    linear-gradient(to right, rgba(35, 43, 61, 0.34) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(35, 43, 61, 0.26) 1px, transparent 1px);
  background-size: 96px 96px;
  color: var(--paper);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.75;
  min-height: 100vh;
  padding-bottom: 0;
}

body::before {
  content: "";
  position: fixed;
  inset: 0 0 auto 0;
  height: 460px;
  pointer-events: none;
  z-index: 0;
  background:
    radial-gradient(110% 100% at 18% 0%, rgba(139, 92, 246, 0.10), transparent 62%),
    radial-gradient(85% 80% at 88% 0%, rgba(63, 216, 200, 0.07), transparent 62%);
}

body > * { position: relative; z-index: 1; }

h1, h2, h3, h4 { line-height: 1.25; font-weight: 600; }

p { line-height: 1.85; }

strong { color: var(--paper); font-weight: 600; }

::selection { background: rgba(139, 92, 246, 0.4); color: #fff; }

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

/* ---------- 通用工具 ---------- */
.container {
  width: 100%;
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0 var(--gutter);
}

.mono {
  font-family: var(--font-data);
  font-variant-numeric: tabular-nums;
  letter-spacing: 0.02em;
}

.text-mist { color: var(--mist); }

.rule {
  height: 1px;
  border: 0;
  background: var(--line);
  margin: 48px 0;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-data);
  font-size: 11px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--cyan);
}

.eyebrow::before {
  content: "";
  width: 18px;
  height: 1px;
  background: var(--cyan);
  flex: none;
}

.display {
  font-family: var(--font-display);
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  line-height: 1.04;
}

/* ---------- 网格 ---------- */
.grid-12 {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  gap: 24px;
}

.col-3, .col-4, .col-5, .col-6, .col-7, .col-8, .col-9, .col-12 {
  grid-column: span 12;
  min-width: 0;
}

.layout-asym {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 28px;
}

@media (min-width: 760px) {
  .col-3, .col-4 { grid-column: span 6; }
}

@media (min-width: 1024px) {
  .col-3 { grid-column: span 3; }
  .col-4 { grid-column: span 4; }
  .col-5 { grid-column: span 5; }
  .col-6 { grid-column: span 6; }
  .col-7 { grid-column: span 7; }
  .col-8 { grid-column: span 8; }
  .col-9 { grid-column: span 9; }
  .layout-asym { grid-template-columns: minmax(200px, 30%) minmax(0, 1fr); gap: 44px; }
}

/* ---------- 跳转链接 ---------- */
.skip-link {
  position: fixed;
  top: 10px;
  left: 10px;
  z-index: 300;
  padding: 9px 16px;
  border-radius: var(--radius);
  background: var(--cyan);
  color: var(--ink-950);
  font-size: 14px;
  font-weight: 600;
  transform: translateY(-180%);
  transition: transform 0.16s var(--ease);
}

.skip-link:focus { transform: translateY(0); }

#main-content { scroll-margin-top: 84px; }

/* ==========================================================================
   命令栏导航
   ========================================================================== */
.cmd-bar {
  position: sticky;
  top: 0;
  z-index: 100;
  --bar-h: 56px;
  background: rgba(10, 13, 22, 0.94);
  border-bottom: 1px solid var(--line);
  -webkit-backdrop-filter: blur(10px);
  backdrop-filter: blur(10px);
}

.cmd-bar[data-collapsed="true"] { --bar-h: 44px; }

.cmd-bar__inner {
  display: flex;
  align-items: center;
  gap: 18px;
  height: var(--bar-h);
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0 var(--gutter);
  transition: height 0.18s var(--ease);
}

/* 品牌 */
.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  flex: none;
  min-width: 0;
}

.brand__mark {
  font-family: var(--font-data);
  font-size: 17px;
  font-weight: 700;
  letter-spacing: 0.08em;
  color: var(--paper);
  background: var(--ink-800);
  border: 1px solid var(--line);
  border-left: 2px solid var(--cyan);
  border-radius: var(--radius);
  padding: 2px 8px 3px;
  line-height: 1.3;
}

.brand__text {
  display: flex;
  flex-direction: column;
  line-height: 1.15;
  min-width: 0;
}

.brand__name {
  font-family: var(--font-display);
  font-size: 15px;
  letter-spacing: 0.22em;
  color: var(--paper);
}

.brand__tagline {
  font-size: 11px;
  letter-spacing: 0.05em;
  color: var(--mist);
  white-space: nowrap;
}

/* 栏目切换 */
.cmd-nav {
  flex: 1 1 auto;
  min-width: 0;
}

.cmd-nav__list {
  display: flex;
  align-items: center;
  gap: 2px;
}

.cmd-nav__item { min-width: 0; }

.cmd-nav__link {
  display: flex;
  align-items: baseline;
  gap: 6px;
  padding: 7px 9px;
  border-left: 2px solid transparent;
  border-radius: var(--radius);
  font-size: 13px;
  color: var(--mist);
  white-space: nowrap;
  transition: color 0.12s var(--ease), background-color 0.12s var(--ease), border-color 0.12s var(--ease);
}

.cmd-nav__link:hover {
  color: var(--paper);
  background: rgba(35, 43, 61, 0.7);
}

.cmd-nav__index {
  font-family: var(--font-data);
  font-size: 10px;
  letter-spacing: 0.06em;
  color: var(--violet);
  transition: color 0.12s var(--ease);
}

.cmd-nav__label { min-width: 0; overflow: hidden; text-overflow: ellipsis; }

.cmd-nav__link[aria-current="page"] {
  background: rgba(139, 92, 246, 0.16);
  border-left-color: var(--cyan);
  color: var(--paper);
}

.cmd-nav__link[aria-current="page"] .cmd-nav__index { color: var(--cyan); }

/* 状态区 */
.cmd-bar__status {
  display: flex;
  align-items: center;
  gap: 16px;
  flex: none;
}

.status-dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--moss);
  box-shadow: 0 0 0 3px rgba(123, 154, 107, 0.14);
  flex: none;
}

.status-dot--live {
  background: var(--orange);
  box-shadow: 0 0 0 3px rgba(255, 106, 43, 0.14), 0 0 10px rgba(255, 106, 43, 0.55);
  animation: dot-pulse 2.4s ease-in-out infinite;
}

@keyframes dot-pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.72; }
}

.cmd-status__cell {
  display: flex;
  flex-direction: column;
  line-height: 1.15;
  gap: 1px;
}

.cmd-status__label {
  font-size: 10px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--mist);
}

.cmd-status__value {
  font-family: var(--font-data);
  font-variant-numeric: tabular-nums;
  font-size: 13px;
  color: var(--paper);
  white-space: nowrap;
}

.cmd-status__value--orange { color: var(--orange); }
.cmd-status__value--amber { color: var(--amber); }

/* 按钮 */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  height: 36px;
  padding: 0 14px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--ink-800);
  color: var(--paper);
  font-size: 13px;
  letter-spacing: 0.04em;
  white-space: nowrap;
  transition: border-color 0.12s var(--ease), background-color 0.12s var(--ease), color 0.12s var(--ease);
}

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

.btn--primary {
  background: rgba(139, 92, 246, 0.16);
  border-color: rgba(139, 92, 246, 0.5);
}

.btn--primary:hover {
  background: rgba(139, 92, 246, 0.3);
  border-color: var(--violet);
  color: #fff;
}

.btn--ghost { background: transparent; }

.btn--sm { height: 28px; padding: 0 10px; font-size: 12px; }

.cmd-bar__cta { flex: none; }

/* 移动导航按钮 */
.nav-toggle {
  display: none;
  flex: none;
  height: 32px;
  padding: 0 12px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--ink-800);
  color: var(--mist);
  font-family: var(--font-data);
  font-size: 12px;
  letter-spacing: 0.1em;
  transition: color 0.12s var(--ease), border-color 0.12s var(--ease), background-color 0.12s var(--ease);
}

.nav-toggle:hover { color: var(--paper); border-color: rgba(63, 216, 200, 0.5); }

.nav-toggle[aria-expanded="true"] {
  color: var(--ink-950);
  background: var(--cyan);
  border-color: var(--cyan);
}

.nav-toggle__label { display: inline-block; }

/* ==========================================================================
   页脚
   ========================================================================== */
.site-footer {
  position: relative;
  margin-top: 104px;
  background: var(--ink-950);
  border-top: 1px solid var(--line);
}

.site-footer::before {
  content: "";
  position: absolute;
  top: -1px;
  left: 0;
  width: 132px;
  height: 2px;
  background: var(--cyan);
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.7fr repeat(4, minmax(0, 1fr));
  gap: 32px;
  padding: 56px 0 36px;
}

.footer-brand { min-width: 0; }

.footer-brand__mark {
  display: inline-block;
  font-family: var(--font-data);
  font-size: 24px;
  font-weight: 700;
  letter-spacing: 0.1em;
  color: var(--paper);
  padding-bottom: 5px;
  border-bottom: 1px solid var(--violet);
}

.footer-brand__name {
  margin-top: 14px;
  font-family: var(--font-display);
  font-size: 15px;
  letter-spacing: 0.22em;
  color: var(--paper);
}

.footer-brand__desc {
  margin-top: 10px;
  max-width: 28ch;
  font-size: 13px;
  line-height: 1.8;
  color: var(--mist);
}

.footer-col { min-width: 0; }

.footer-col__title {
  display: flex;
  align-items: baseline;
  gap: 8px;
  font-family: var(--font-display);
  font-size: 13px;
  font-weight: 400;
  letter-spacing: 0.18em;
  color: var(--paper);
}

.footer-col__index {
  font-family: var(--font-data);
  font-size: 11px;
  letter-spacing: 0.04em;
  color: var(--violet);
}

.footer-col__list {
  margin-top: 14px;
  display: flex;
  flex-direction: column;
  gap: 9px;
}

.footer-col__link {
  display: inline-block;
  font-size: 13.5px;
  color: var(--mist);
  border-bottom: 1px solid transparent;
  transition: color 0.12s var(--ease), border-color 0.12s var(--ease);
}

.footer-col__link:hover {
  color: var(--cyan);
  border-bottom-color: rgba(63, 216, 200, 0.5);
}

.footer-contact {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px 32px;
  padding: 24px 0;
  border-top: 1px solid var(--line);
}

.footer-contact__item {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  min-width: 0;
}

.footer-contact__label {
  font-size: 11px;
  letter-spacing: 0.14em;
  color: var(--violet);
  flex: none;
}

.footer-contact__value {
  font-family: var(--font-data);
  font-variant-numeric: tabular-nums;
  font-size: 13px;
  color: var(--mist);
  word-break: break-all;
}

.copy-btn {
  flex: none;
  padding: 2px 8px 3px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  font-family: var(--font-data);
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--mist);
  transition: color 0.12s var(--ease), border-color 0.12s var(--ease), background-color 0.12s var(--ease);
}

.copy-btn:hover { color: var(--cyan); border-color: var(--cyan); }

.copy-btn[data-copied="true"] {
  color: var(--ink-950);
  background: var(--cyan);
  border-color: var(--cyan);
}

.footer-note {
  padding-top: 16px;
  border-top: 1px solid var(--line);
  font-size: 12px;
  line-height: 1.9;
  color: var(--mist);
}

.footer-legal {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 10px 24px;
  padding: 16px 0 40px;
}

.footer-legal__line {
  font-size: 12px;
  line-height: 1.9;
  color: var(--mist);
}

.footer-legal__line a {
  color: var(--mist);
  transition: color 0.12s var(--ease);
}

.footer-legal__line a:hover { color: var(--cyan); }

.footer-legal__sep {
  margin: 0 8px;
  color: var(--line);
}

/* ==========================================================================
   通用组件
   ========================================================================== */

/* 面包屑 */
.breadcrumb { padding: 22px 0 0; }

.breadcrumb__list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  font-family: var(--font-data);
  font-size: 12px;
  color: var(--mist);
}

.breadcrumb__item {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  min-width: 0;
}

.breadcrumb__link {
  color: var(--mist);
  transition: color 0.12s var(--ease);
}

.breadcrumb__link:hover { color: var(--cyan); }

.breadcrumb__sep { color: var(--line); }

.breadcrumb__current { color: var(--paper); }

/* 章节头 */
.section { margin-top: 76px; }

.section-head {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-end;
  justify-content: space-between;
  gap: 12px 24px;
  padding-bottom: 14px;
  border-bottom: 1px solid var(--line);
}

.section-head__group { min-width: 0; }

.section-head__title {
  font-family: var(--font-serif);
  font-size: 24px;
  font-weight: 600;
  letter-spacing: 0.01em;
  color: var(--paper);
}

.section-head__eyebrow {
  display: block;
  margin-bottom: 8px;
  font-family: var(--font-data);
  font-size: 11px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--cyan);
}

.section-head__meta {
  font-family: var(--font-data);
  font-size: 12px;
  color: var(--mist);
  white-space: nowrap;
}

/* 面板 */
.panel {
  position: relative;
  background: var(--ink-800);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--inset);
}

.panel__head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 13px 18px;
  border-bottom: 1px solid var(--line);
}

.panel__title {
  font-family: var(--font-display);
  font-size: 14px;
  font-weight: 400;
  letter-spacing: 0.16em;
  color: var(--paper);
}

.panel__index {
  font-family: var(--font-data);
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--violet);
}

.panel__body { padding: 18px; }

.panel--flush .panel__body { padding: 0; }

/* 标签 */
.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  height: 22px;
  padding: 0 9px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: rgba(29, 36, 52, 0.6);
  font-size: 11px;
  letter-spacing: 0.06em;
  color: var(--mist);
  white-space: nowrap;
}

.tag--cyan { color: var(--cyan); border-color: rgba(63, 216, 200, 0.4); }
.tag--violet { color: var(--violet); border-color: rgba(139, 92, 246, 0.42); }
.tag--amber { color: var(--amber); border-color: rgba(233, 180, 76, 0.42); }
.tag--moss { color: var(--moss); border-color: rgba(123, 154, 107, 0.46); }
.tag--clay { color: var(--clay); border-color: rgba(196, 105, 74, 0.5); }
.tag--orange { color: var(--orange); border-color: rgba(255, 106, 43, 0.46); }

/* 分段切换 */
.tabs { margin-top: 8px; }

.tabs__list {
  display: flex;
  flex-wrap: wrap;
  gap: 4px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--line);
}

.tabs__tab {
  height: 30px;
  padding: 0 12px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: transparent;
  font-family: var(--font-data);
  font-size: 12.5px;
  letter-spacing: 0.04em;
  color: var(--mist);
  transition: background-color 0.12s var(--ease), color 0.12s var(--ease), border-color 0.12s var(--ease);
}

.tabs__tab:hover { color: var(--paper); border-color: rgba(63, 216, 200, 0.5); }

.tabs__tab[aria-selected="true"] {
  background: rgba(139, 92, 246, 0.18);
  border-color: var(--violet);
  color: var(--paper);
}

.tabs__panel {
  padding-top: 22px;
  animation: fade-in 0.12s var(--ease) both;
}

.tabs__panel[hidden] { display: none; }

@keyframes fade-in {
  from { opacity: 0; }
  to { opacity: 1; }
}

/* 图像容器 */
.media-frame {
  position: relative;
  aspect-ratio: 16 / 9;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background-color: var(--ink-700);
  background-image:
    linear-gradient(135deg, rgba(139, 92, 246, 0.08), transparent 58%),
    repeating-linear-gradient(0deg, rgba(35, 43, 61, 0.6) 0 1px, transparent 1px 6px);
}

.media-frame--4x3 { aspect-ratio: 4 / 3; }
.media-frame--1x1 { aspect-ratio: 1 / 1; }
.media-frame--21x9 { aspect-ratio: 21 / 9; }

.media-frame__img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.media-frame__ph {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
}

.media-frame__num {
  font-family: var(--font-data);
  font-size: 44px;
  letter-spacing: 0.08em;
  color: rgba(236, 231, 220, 0.16);
}

.media-frame__cap {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  padding: 10px 12px;
  font-family: var(--font-data);
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--mist);
  background: linear-gradient(to top, rgba(7, 10, 17, 0.92), transparent);
}

/* 长文 */
.prose {
  max-width: 68ch;
  font-size: 15.5px;
  line-height: 1.85;
  color: var(--paper);
}

.prose p + p { margin-top: 1em; }

.prose h2 {
  margin: 1.7em 0 0.5em;
  font-family: var(--font-serif);
  font-size: 20px;
}

.prose h3 {
  margin: 1.4em 0 0.4em;
  font-size: 16px;
}

.prose ul, .prose ol { margin: 0.9em 0; }

.prose li {
  position: relative;
  padding-left: 16px;
  margin: 0.35em 0;
  color: var(--mist);
}

.prose li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.78em;
  width: 7px;
  height: 1px;
  background: var(--cyan);
}

.prose a {
  color: var(--cyan);
  border-bottom: 1px solid rgba(63, 216, 200, 0.35);
}

/* 滚动进度条 */
.scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  z-index: 200;
  width: 100%;
  height: 2px;
  transform: scaleX(0);
  transform-origin: 0 50%;
  background: linear-gradient(90deg, var(--violet), var(--cyan));
  pointer-events: none;
}

/* 返回顶部 */
.back-to-top {
  position: fixed;
  right: 20px;
  bottom: 20px;
  z-index: 90;
  width: 44px;
  height: 44px;
  display: grid;
  place-items: center;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: rgba(20, 25, 38, 0.92);
  color: var(--mist);
  font-family: var(--font-data);
  font-size: 11px;
  letter-spacing: 0.06em;
  opacity: 0;
  visibility: hidden;
  transform: translateY(8px);
  transition: opacity 0.18s var(--ease), transform 0.18s var(--ease), visibility 0.18s var(--ease), color 0.12s var(--ease), border-color 0.12s var(--ease);
}

.back-to-top:hover { color: var(--cyan); border-color: var(--cyan); }

.back-to-top[data-visible="true"] {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

/* 渐显 */
.has-js .reveal {
  opacity: 0;
  transform: translateY(12px);
  transition: opacity 0.4s var(--ease), transform 0.4s var(--ease);
}

.has-js .reveal[data-revealed="true"] {
  opacity: 1;
  transform: none;
}

/* ==========================================================================
   响应式
   ========================================================================== */
@media (max-width: 1180px) {
  .brand__tagline { display: none; }
  .cmd-status__cell--wide { display: none; }
  .cmd-bar__status { gap: 12px; }
}

@media (max-width: 960px) {
  .cmd-bar__inner { gap: 12px; }

  .nav-toggle { display: inline-flex; align-items: center; }

  .brand__text { display: none; }

  .cmd-nav {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    display: block;
    padding: 8px var(--gutter) 20px;
    max-height: calc(100vh - var(--bar-h));
    overflow-y: auto;
    background: var(--ink-800);
    border-bottom: 1px solid var(--line);
    box-shadow: 0 26px 44px -22px rgba(0, 0, 0, 0.85);
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
    transform: translateY(-6px);
    transition: opacity 0.16s var(--ease), transform 0.16s var(--ease), visibility 0.16s var(--ease);
  }

  .cmd-nav[data-open="true"] {
    opacity: 1;
    visibility: visible;
    pointer-events: auto;
    transform: translateY(0);
  }

  .cmd-nav__list {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
  }

  .cmd-nav__link {
    padding: 13px 12px;
    font-size: 15px;
    border-radius: 0;
    border-bottom: 1px solid rgba(35, 43, 61, 0.75);
  }

  .cmd-nav__item:last-child .cmd-nav__link { border-bottom: 0; }

  .cmd-nav__index { font-size: 11px; }

  .footer-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 28px;
    padding: 44px 0 28px;
  }

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

@media (max-width: 720px) {
  :root { --gutter: 18px; }

  .cmd-bar__status { display: none; }

  .cmd-bar__cta { height: 32px; padding: 0 11px; font-size: 12.5px; }

  .site-footer { margin-top: 72px; }

  .section { margin-top: 56px; }

  .section-head__title { font-size: 20px; }

  .footer-legal { padding: 16px 0 32px; }

  .footer-legal__line:last-child { display: flex; flex-wrap: wrap; gap: 4px 0; }
}

@media (max-width: 520px) {
  .cmd-bar__cta { display: none; }

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

  .footer-contact { gap: 14px 20px; }

  .footer-contact__value { font-size: 12.5px; }

  .back-to-top { right: 14px; bottom: 14px; width: 40px; height: 40px; }
}

/* ==========================================================================
   降低动态效果
   ========================================================================== */
@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;
  }

  .has-js .reveal {
    opacity: 1;
    transform: none;
  }

  .status-dot--live { animation: none; }
}