/* ==========================================================================
   NG娱乐 · 导航志 — 共享站点样式 /assets/site.css
   ========================================================================== */

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

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-h) + 14px);
  background: #0A1424;
}

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

ul, ol { list-style: none; }

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

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

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

button {
  background: none;
  border: 0;
  cursor: pointer;
}

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

/* 2. Tokens --------------------------------------------------------------- */
:root {
  --ink-950: #0A1424;
  --ink-900: #0F1E33;
  --ink-800: #16283F;
  --cyan-400: #3BE3DC;
  --cyan-650: #128E8C;
  --amber-500: #F5A524;
  --amber-300: #FFCE7A;
  --paper-050: #EAF2F8;
  --mute-400: #8AA0B6;
  --line-700: #27405C;

  --bg: var(--ink-950);
  --text: var(--paper-050);
  --body-text: #C3D2E0;

  --shell: 1240px;
  --gutter: clamp(18px, 4vw, 40px);
  --header-h: 78px;
  --measure: 44em;
  --radius: 2px;

  --sans: "Noto Sans SC", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", system-ui, -apple-system, sans-serif;
  --mono: "JetBrains Mono", "SFMono-Regular", "SF Mono", Consolas, "Noto Sans Mono", monospace;

  --ease: cubic-bezier(.2, .7, .3, 1);
}

/* 3. Base ----------------------------------------------------------------- */
body {
  min-height: 100vh;
  background-color: var(--bg);
  color: var(--text);
  font-family: var(--sans);
  font-size: 17px;
  line-height: 1.78;
  font-weight: 400;
  padding-top: var(--header-h);
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

/* 网格坐标场 + 右上角微光 */
body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  background-image:
    repeating-linear-gradient(90deg, rgba(39, 64, 92, .38) 0 1px, transparent 1px 96px),
    repeating-linear-gradient(0deg, rgba(39, 64, 92, .3) 0 1px, transparent 1px 96px);
  -webkit-mask-image: radial-gradient(120% 88% at 72% 0%, #000 18%, transparent 76%);
  mask-image: radial-gradient(120% 88% at 72% 0%, #000 18%, transparent 76%);
}

body::after {
  content: "";
  position: fixed;
  top: -180px;
  right: -140px;
  width: 560px;
  height: 560px;
  z-index: 0;
  pointer-events: none;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(59, 227, 220, .16), rgba(59, 227, 220, 0) 68%);
}

#main-content {
  position: relative;
  z-index: 1;
}

h1, h2, h3, h4 {
  font-weight: 900;
  letter-spacing: -.02em;
  line-height: 1.12;
  color: var(--paper-050);
}

::selection {
  background: var(--cyan-400);
  color: var(--ink-950);
}

:focus-visible {
  outline: 2px solid var(--amber-500);
  outline-offset: 2px;
  border-radius: 2px;
}

/* 4. 排版工具 ------------------------------------------------------------- */
.display {
  font-size: clamp(34px, 5.4vw, 64px);
  font-weight: 900;
  letter-spacing: -.03em;
  line-height: 1.04;
}

.h2 {
  font-size: clamp(24px, 3vw, 36px);
  font-weight: 900;
  letter-spacing: -.02em;
  line-height: 1.14;
}

.h3 {
  font-size: clamp(18px, 2vw, 24px);
  font-weight: 900;
  letter-spacing: -.01em;
  line-height: 1.24;
}

.lede {
  font-size: clamp(17px, 1.6vw, 20px);
  line-height: 1.72;
  color: #B9CADA;
  max-width: 34em;
}

.mono {
  font-family: var(--mono);
  font-size: .92em;
  letter-spacing: .02em;
}

.prose {
  max-width: var(--measure);
  font-size: 16.5px;
  line-height: 1.78;
  color: var(--body-text);
}

.prose--wide { max-width: 58em; }

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

.prose strong { color: var(--paper-050); font-weight: 700; }

.prose a {
  color: var(--cyan-400);
  border-bottom: 1px solid rgba(59, 227, 220, .45);
}

.prose a:hover {
  background: rgba(59, 227, 220, .1);
  border-bottom-color: var(--cyan-400);
}

.prose ul { margin-top: .8em; }

.prose li {
  position: relative;
  padding-left: 20px;
  margin-top: .45em;
}

.prose li::before {
  content: "";
  position: absolute;
  left: 0;
  top: .78em;
  width: 8px;
  height: 2px;
  background: var(--cyan-400);
}

/* 5. 布局容器 ------------------------------------------------------------- */
.shell {
  width: 100%;
  max-width: var(--shell);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.section {
  position: relative;
  padding-block: clamp(44px, 7vw, 88px);
}

.section--tight { padding-block: clamp(28px, 4vw, 50px); }

.section--panel {
  background: var(--ink-900);
  border-top: 1px solid var(--line-700);
  border-bottom: 1px solid var(--line-700);
}

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

.col-2 { grid-column: span 2; }
.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; }
.col-10 { grid-column: span 10; }
.col-12 { grid-column: span 12; }

/* 偏置网格：左侧刻度导航 + 主内容 */
.layout-rail {
  display: grid;
  grid-template-columns: 196px minmax(0, 1fr);
  gap: clamp(24px, 4vw, 56px);
  align-items: start;
}

.rail {
  position: sticky;
  top: calc(var(--header-h) + 26px);
  align-self: start;
  display: flex;
  flex-direction: column;
  gap: 2px;
  padding-top: 8px;
  border-left: 1px solid var(--line-700);
  padding-left: 0;
}

.rail__caption {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: .16em;
  color: #3C5875;
  margin-bottom: 12px;
  padding-left: 2px;
}

.rail__link {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 7px 0 7px 2px;
  font-size: 13.5px;
  color: var(--mute-400);
  transition: color .2s var(--ease);
}

.rail__tick {
  flex: 0 0 auto;
  width: 16px;
  height: 2px;
  background: var(--line-700);
  transition: width .2s var(--ease), background .2s var(--ease), box-shadow .2s var(--ease);
}

.rail__link:hover { color: var(--paper-050); }
.rail__link:hover .rail__tick { background: var(--cyan-650); }

.rail__link[aria-current="true"] { color: var(--cyan-400); }

.rail__link[aria-current="true"] .rail__tick {
  width: 30px;
  background: var(--cyan-400);
  box-shadow: 0 0 10px rgba(59, 227, 220, .55);
}

/* 6. 章节标题三段式 ------------------------------------------------------- */
.section-head {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-bottom: clamp(20px, 3vw, 34px);
}

.section-head__num {
  display: flex;
  align-items: center;
  gap: 12px;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--cyan-400);
}

.section-head__num::after {
  content: "";
  width: min(180px, 30vw);
  height: 1px;
  background: var(--line-700);
}

.section-head__title { font-size: clamp(22px, 2.8vw, 32px); }

.section-head__note {
  color: var(--mute-400);
  font-size: 15px;
  max-width: 48em;
}

/* 7. 按钮 ----------------------------------------------------------------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 10px 18px;
  border: 1px solid var(--cyan-400);
  border-radius: var(--radius);
  background: transparent;
  color: var(--cyan-400);
  font-size: 14px;
  font-weight: 700;
  letter-spacing: .02em;
  line-height: 1.4;
  white-space: nowrap;
  transition: background .18s var(--ease), color .18s var(--ease),
              border-color .18s var(--ease), transform .18s var(--ease);
}

.btn:hover { background: rgba(59, 227, 220, .12); }
.btn:active { transform: translateY(1px); }

.btn--solid {
  background: var(--cyan-400);
  border-color: var(--cyan-400);
  color: var(--ink-950);
}

.btn--solid:hover {
  background: var(--cyan-650);
  border-color: var(--cyan-650);
  color: var(--paper-050);
}

.btn--quiet {
  border-color: var(--line-700);
  color: var(--paper-050);
}

.btn--quiet:hover {
  border-color: var(--cyan-400);
  color: var(--cyan-400);
  background: rgba(59, 227, 220, .07);
}

.btn--amber {
  border-color: var(--amber-500);
  color: var(--amber-300);
}

.btn--amber:hover { background: rgba(245, 165, 36, .14); }

.btn--sm { padding: 7px 13px; font-size: 13px; }
.btn--block { width: 100%; }

/* 8. 标签 / 芯片 / 卡片 --------------------------------------------------- */
.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 3px 9px;
  border: 1px solid var(--cyan-400);
  color: var(--cyan-400);
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: .08em;
  text-transform: uppercase;
  line-height: 1.5;
}

.tag--amber { border-color: var(--amber-500); color: var(--amber-300); }
.tag--mute { border-color: var(--line-700); color: var(--mute-400); }
.tag--fill { background: rgba(59, 227, 220, .12); }

.chip-group {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.chip {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 7px 14px;
  border: 1px solid var(--line-700);
  background: transparent;
  color: var(--mute-400);
  font-size: 14px;
  line-height: 1.4;
  transition: color .18s var(--ease), border-color .18s var(--ease), background .18s var(--ease);
}

.chip:hover {
  color: var(--paper-050);
  border-color: var(--cyan-650);
}

.chip[aria-pressed="true"] {
  color: var(--cyan-400);
  border-color: var(--cyan-400);
  background: rgba(59, 227, 220, .1);
}

.card {
  position: relative;
  padding: clamp(18px, 2.4vw, 26px);
  background: var(--ink-800);
  border: 1px solid var(--line-700);
}

.card--notch {
  clip-path: polygon(0 0, calc(100% - 16px) 0, 100% 16px,
                     100% 100%, 16px 100%, 0 calc(100% - 16px));
}

.card--raised {
  background: var(--ink-900);
  box-shadow: 0 20px 44px -30px rgba(0, 0, 0, .95);
}

.card__kicker {
  display: block;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: .14em;
  color: var(--cyan-400);
  text-transform: uppercase;
}

.card__title {
  margin-top: 8px;
  font-size: 19px;
  font-weight: 900;
  letter-spacing: -.01em;
  line-height: 1.3;
}

.card__body {
  margin-top: 10px;
  font-size: 15.5px;
  line-height: 1.72;
  color: var(--body-text);
}

/* 9. 分段切换 ------------------------------------------------------------- */
.tabs { width: 100%; }

.tabs__list {
  display: flex;
  flex-wrap: wrap;
  border-bottom: 1px solid var(--line-700);
}

.tab {
  position: relative;
  padding: 12px 18px;
  border-bottom: 2px solid transparent;
  margin-bottom: -1px;
  color: var(--mute-400);
  font-size: 15px;
  font-weight: 700;
  transition: color .18s var(--ease), border-color .18s var(--ease), background .18s var(--ease);
}

.tab:hover {
  color: var(--paper-050);
  background: rgba(22, 40, 63, .7);
}

.tab__idx {
  margin-right: 8px;
  font-family: var(--mono);
  font-size: 11px;
  font-weight: 400;
  color: #40597A;
}

.tab[aria-selected="true"] {
  color: var(--cyan-400);
  border-bottom-color: var(--cyan-400);
}

.tab[aria-selected="true"] .tab__idx { color: var(--cyan-400); }

.tab-panel {
  padding-top: clamp(18px, 2.6vw, 28px);
  animation: ng-panel-in .24s var(--ease) both;
}

.tab-panel[hidden] { display: none; }

@keyframes ng-panel-in {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: none; }
}

/* 10. 折叠面板 ------------------------------------------------------------ */
.fold {
  margin-top: -1px;
  background: var(--ink-900);
  border: 1px solid var(--line-700);
  border-left: 2px solid var(--line-700);
  transition: border-color .22s var(--ease), background .22s var(--ease);
}

.fold[open] {
  background: var(--ink-800);
  border-left-color: var(--cyan-400);
}

.fold__summary {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 15px 18px;
  font-size: 16px;
  font-weight: 700;
  cursor: pointer;
  list-style: none;
}

.fold__summary::-webkit-details-marker { display: none; }

.fold__summary::after {
  content: "+";
  margin-left: auto;
  font-family: var(--mono);
  font-size: 18px;
  color: var(--cyan-400);
}

.fold[open] .fold__summary::after { content: "–"; }

.fold__idx {
  font-family: var(--mono);
  font-size: 12px;
  font-weight: 400;
  color: var(--mute-400);
}

.fold__body {
  padding: 0 18px 18px;
  font-size: 15.5px;
  line-height: 1.75;
  color: var(--body-text);
  max-width: 60em;
}

/* 11. 步骤卡 -------------------------------------------------------------- */
.steps {
  display: grid;
  gap: 14px;
}

.step {
  display: grid;
  grid-template-columns: 44px minmax(0, 1fr);
  gap: 16px;
  padding: 16px 18px;
  background: var(--ink-800);
  border: 1px solid var(--line-700);
}

.step__num {
  padding-top: 3px;
  border-right: 1px solid var(--line-700);
  font-family: var(--mono);
  font-size: 13px;
  color: var(--cyan-400);
}

.step__title {
  font-size: 16.5px;
  font-weight: 900;
  letter-spacing: -.01em;
}

.step__body {
  margin-top: 6px;
  font-size: 15.5px;
  line-height: 1.72;
  color: var(--body-text);
}

/* 12. 面包屑 -------------------------------------------------------------- */
.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  padding-block: 18px;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: .06em;
  color: var(--mute-400);
}

.breadcrumb li { display: flex; align-items: center; gap: 8px; }

.breadcrumb li::after {
  content: "/";
  color: var(--line-700);
}

.breadcrumb li:last-child::after { content: ""; }

.breadcrumb a { color: var(--mute-400); }
.breadcrumb a:hover { color: var(--cyan-400); }
.breadcrumb [aria-current="page"] { color: var(--paper-050); }

/* 13. 图片容器基础规则 ---------------------------------------------------- */
.media {
  position: relative;
  overflow: hidden;
  aspect-ratio: 16 / 9;
  border: 1px solid var(--line-700);
  background: linear-gradient(140deg, var(--ink-800) 0%, var(--ink-900) 65%, var(--ink-950) 100%);
}

.media::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background-image: repeating-linear-gradient(0deg, rgba(59, 227, 220, .07) 0 1px, transparent 1px 9px);
}

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

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

.media__caption,
.figure__caption {
  margin-top: 8px;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: .04em;
  color: var(--mute-400);
}

.figure { margin: 0; }

/* 14. 显现 ---------------------------------------------------------------- */
.reveal {
  opacity: 0;
  transform: translateY(14px);
  transition: opacity .5s var(--ease), transform .5s var(--ease);
}

.reveal.is-visible {
  opacity: 1;
  transform: none;
}

/* 15. 页头 ---------------------------------------------------------------- */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 60;
  background: rgba(10, 20, 36, .93);
  border-bottom: 1px solid var(--line-700);
  -webkit-backdrop-filter: blur(14px) saturate(140%);
  backdrop-filter: blur(14px) saturate(140%);
}

.site-header__inner {
  display: flex;
  align-items: center;
  gap: clamp(12px, 2vw, 26px);
  min-height: var(--header-h);
}

.skip-link {
  position: absolute;
  left: 12px;
  top: -80px;
  z-index: 90;
  padding: 10px 16px;
  background: var(--cyan-400);
  color: var(--ink-950);
  font-size: 14px;
  font-weight: 700;
  transition: top .18s var(--ease);
}

.skip-link:focus {
  top: 12px;
  outline-color: var(--ink-950);
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  flex: 0 0 auto;
  color: var(--paper-050);
}

.brand__mark {
  display: grid;
  place-items: center;
  width: 38px;
  height: 38px;
  border: 1px solid var(--cyan-400);
  background: linear-gradient(180deg, rgba(59, 227, 220, .16), rgba(59, 227, 220, 0));
  color: var(--cyan-400);
  font-family: var(--mono);
  font-size: 15px;
  font-weight: 700;
  letter-spacing: .02em;
}

.brand__text {
  display: flex;
  flex-direction: column;
  line-height: 1.18;
}

.brand__name {
  font-size: 17px;
  font-weight: 900;
  letter-spacing: -.01em;
}

.brand__sub {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: .08em;
  color: var(--mute-400);
}

.brand__coord {
  padding-left: 12px;
  border-left: 1px solid var(--line-700);
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: .1em;
  color: #4B668A;
}

.nav {
  flex: 1 1 auto;
  display: flex;
  justify-content: center;
}

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

.nav__list > li { display: flex; }

.nav__link {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  padding: 9px clamp(8px, 1vw, 13px);
  border: 1px solid transparent;
  color: var(--mute-400);
  font-size: 15px;
  line-height: 1.4;
  transition: color .18s var(--ease), background .18s var(--ease), border-color .18s var(--ease);
}

.nav__idx {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: .06em;
  color: #40597A;
  transition: color .18s var(--ease);
}

.nav__link:hover {
  color: var(--paper-050);
  background: rgba(22, 40, 63, .75);
  border-color: var(--line-700);
}

.nav__link:hover .nav__idx { color: var(--cyan-400); }

.nav__link[aria-current="page"] {
  color: var(--cyan-400);
  border-color: var(--cyan-400);
  background: rgba(59, 227, 220, .09);
}

.nav__link[aria-current="page"] .nav__idx { color: var(--cyan-400); }

.site-header__actions {
  display: flex;
  align-items: center;
  gap: 10px;
  flex: 0 0 auto;
}

.header__cta { padding: 9px 15px; }

.nav-toggle {
  display: none;
  align-items: center;
  gap: 9px;
  padding: 9px 12px;
  border: 1px solid var(--line-700);
  color: var(--paper-050);
  font-size: 13px;
  font-weight: 700;
  transition: border-color .18s var(--ease), color .18s var(--ease);
}

.nav-toggle:hover { border-color: var(--cyan-400); color: var(--cyan-400); }

.nav-toggle__bars {
  display: grid;
  gap: 4px;
  width: 16px;
}

.nav-toggle__bars span {
  display: block;
  height: 2px;
  background: var(--cyan-400);
  transition: transform .2s var(--ease), opacity .2s var(--ease);
}

.nav-toggle[aria-expanded="true"] .nav-toggle__bars span:nth-child(1) {
  transform: translateY(6px) rotate(45deg);
}

.nav-toggle[aria-expanded="true"] .nav-toggle__bars span:nth-child(2) { opacity: 0; }

.nav-toggle[aria-expanded="true"] .nav-toggle__bars span:nth-child(3) {
  transform: translateY(-6px) rotate(-45deg);
}

.nav-toggle__label {
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: .1em;
}

.site-header__progress {
  position: absolute;
  left: 0;
  right: 0;
  bottom: -1px;
  height: 2px;
  background: var(--line-700);
  overflow: hidden;
}

.site-header__progress span {
  display: block;
  width: 0;
  height: 100%;
  background: var(--cyan-400);
  box-shadow: 0 0 12px rgba(59, 227, 220, .65);
  transition: width .12s linear;
}

html.nav-open { overflow: hidden; }

/* 16. 页脚 ---------------------------------------------------------------- */
.site-footer {
  position: relative;
  z-index: 1;
  margin-top: clamp(48px, 7vw, 96px);
  background: var(--ink-900);
  border-top: 1px solid var(--line-700);
}

.site-footer::before {
  content: "";
  position: absolute;
  top: -1px;
  left: 0;
  width: min(260px, 42vw);
  height: 2px;
  background: var(--cyan-400);
  box-shadow: 0 0 14px rgba(59, 227, 220, .55);
}

.footer__grid {
  display: grid;
  grid-template-columns: 1.5fr 1.1fr 1.1fr 1.35fr;
  gap: clamp(24px, 3vw, 44px);
  padding-block: clamp(36px, 5vw, 64px);
}

.footer__col {
  display: flex;
  flex-direction: column;
  min-width: 0;
}

.footer__col--brand { gap: 0; }

.footer__brand {
  font-size: 19px;
  font-weight: 900;
  letter-spacing: -.01em;
  color: var(--paper-050);
}

.footer__brand span {
  display: block;
  margin-top: 6px;
  font-family: var(--mono);
  font-size: 11px;
  font-weight: 400;
  letter-spacing: .18em;
  color: var(--cyan-400);
}

.footer__promise {
  margin-top: 14px;
  max-width: 30em;
  font-size: 15px;
  line-height: 1.75;
  color: #B7C7D7;
}

.footer__coord {
  margin-top: 16px;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: .16em;
  color: #3C5875;
}

.footer__title {
  margin-bottom: 14px;
  font-family: var(--mono);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--cyan-400);
}

.footer__list {
  display: flex;
  flex-direction: column;
  gap: 9px;
  font-size: 15px;
}

.footer__list a { color: #C5D4E2; transition: color .18s var(--ease); }
.footer__list a:hover { color: var(--cyan-400); }

.footer__sublist {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 14px;
  margin-top: 8px;
  padding-left: 12px;
  border-left: 1px solid var(--line-700);
  font-size: 13.5px;
}

.footer__sublist a { color: var(--mute-400); }
.footer__sublist a:hover { color: var(--cyan-400); }

.footer__facts {
  display: flex;
  flex-direction: column;
  gap: 12px;
  font-size: 14.5px;
}

.footer__fact dt {
  margin-bottom: 3px;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: .12em;
  color: var(--mute-400);
}

.footer__fact dd {
  color: #C5D4E2;
  line-height: 1.7;
  word-break: break-word;
}

.footer__copyline {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  margin-top: 16px;
}

.copy-btn { align-self: flex-start; }

.copy-state {
  min-height: 18px;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: .06em;
  color: var(--mute-400);
}

.copy-state[data-state="ok"] { color: var(--amber-300); }
.copy-state[data-state="warn"] { color: var(--amber-500); }

.footer__bottom {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 10px 24px;
  padding-block: 18px;
  border-top: 1px solid var(--line-700);
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: .05em;
  color: var(--mute-400);
}

.footer__copy { color: var(--mute-400); }

.footer__legal {
  display: flex;
  flex-wrap: wrap;
  gap: 18px;
}

.footer__legal a { color: var(--mute-400); }
.footer__legal a:hover { color: var(--cyan-400); }

/* 17. 平板 ---------------------------------------------------------------- */
@media (max-width: 1200px) {
  .brand__coord { display: none; }
}

@media (max-width: 1024px) {
  :root { --header-h: 64px; }

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

  .nav-toggle__label { display: none; }

  .site-header__inner { gap: 12px; }

  .brand__mark { width: 34px; height: 34px; font-size: 14px; }

  .nav {
    position: fixed;
    top: var(--header-h);
    left: 0;
    right: 0;
    bottom: 0;
    flex-direction: column;
    justify-content: flex-start;
    padding: 20px var(--gutter) 48px;
    background: var(--ink-900);
    border-top: 1px solid var(--line-700);
    overflow-y: auto;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: opacity .2s var(--ease), transform .2s var(--ease), visibility .2s var(--ease);
  }

  .nav[data-open] {
    opacity: 1;
    visibility: visible;
    transform: none;
  }

  .nav__list {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    width: 100%;
  }

  .nav__list > li { display: block; }

  .nav__link {
    justify-content: flex-start;
    width: 100%;
    padding: 15px 6px;
    border: 0;
    border-bottom: 1px solid var(--line-700);
    font-size: 17px;
  }

  .nav__link:hover { background: rgba(22, 40, 63, .6); }

  .nav__link[aria-current="page"] {
    background: rgba(59, 227, 220, .08);
    box-shadow: inset 3px 0 0 var(--cyan-400);
    padding-left: 16px;
    border-bottom-color: var(--line-700);
  }

  .layout-rail {
    grid-template-columns: minmax(0, 1fr);
    gap: 20px;
  }

  .rail {
    position: static;
    flex-direction: row;
    flex-wrap: wrap;
    gap: 6px 18px;
    align-items: center;
    padding: 10px 0;
    border-left: 0;
    border-bottom: 1px solid var(--line-700);
  }

  .rail__caption { margin: 0 8px 0 0; padding: 0; }

  .col-3, .col-4 { grid-column: span 6; }
  .col-5, .col-7 { grid-column: span 12; }

  .footer__grid { grid-template-columns: 1fr 1fr; }
}

/* 18. 手机 ---------------------------------------------------------------- */
@media (max-width: 680px) {
  body { font-size: 16px; }

  .grid > * { grid-column: 1 / -1; }

  .col-2, .col-3, .col-4, .col-6, .col-8, .col-9, .col-10 {
    grid-column: 1 / -1;
  }

  .brand__sub { display: none; }

  .header__cta { padding: 8px 12px; font-size: 13px; }

  .media { aspect-ratio: 16 / 10; }
  .media--1x1 { aspect-ratio: 4 / 3; }

  .footer__grid { grid-template-columns: 1fr; gap: 30px; }

  .footer__bottom { justify-content: flex-start; }

  .step { grid-template-columns: 34px minmax(0, 1fr); gap: 12px; }

  .tab { padding: 11px 13px; font-size: 14px; }
}

/* 19. 动效降级 ------------------------------------------------------------ */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }

  *,
  *::before,
  *::after {
    animation-duration: .001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .001ms !important;
  }

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

  .tab-panel { animation: none; }

  .site-header__progress span { transition: none; }
}