/* ============================================================
   九游体育入口 · /assets/site.css
   共享外壳：reset / 变量 / 中文排版 / 头部 / 页脚 / 通用组件
   ============================================================ */

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

html {
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: 104px;
}

body {
  margin: 0;
  min-height: 100vh;
}

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

h1, h2, h3, h4, p, figure, blockquote, ul, ol { margin: 0; }
ul, ol { padding: 0; }

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

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

/* ---------- 2. 变量 ---------- */
:root {
  /* 色彩 */
  --ink: #071426;
  --ink-2: #0B2239;
  --slate: #1B3550;
  --line: #2A4A66;
  --line-soft: rgba(42, 74, 102, .62);
  --fog: #E8F1F8;
  --fog-80: rgba(232, 241, 248, .80);
  --fog-62: rgba(232, 241, 248, .62);
  --fog-38: rgba(232, 241, 248, .38);
  --cyan: #34F5E1;
  --orange: #FF7A2F;
  --mint: #63E6A6;
  --violet: #9B7BFF;
  --sky: #3FD8FF;

  /* 字体 */
  --font-display: "Source Han Serif SC", "Noto Serif SC", "Songti SC", "STSong", "SimSun", serif;
  --font-ui: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-mono: "SF Mono", "JetBrains Mono", "Roboto Mono", Menlo, Consolas, "Courier New", monospace;

  /* 尺度 */
  --pad-x: clamp(16px, 4vw, 56px);
  --maxw: 1240px;
  --header-h: 76px;
  --radius: 2px;

  /* 网格纹样 */
  --tick-line: repeating-linear-gradient(90deg, var(--line) 0 1px, transparent 1px 14px);
}

/* ---------- 3. 基础排版 ---------- */
body {
  background-color: var(--ink);
  background-image:
    radial-gradient(1100px 520px at 82% -8%, rgba(63, 216, 255, .10), transparent 68%),
    radial-gradient(760px 420px at 4% 22%, rgba(155, 123, 255, .07), transparent 70%),
    repeating-linear-gradient(180deg, rgba(42, 74, 102, .26) 0 1px, transparent 1px 88px),
    repeating-linear-gradient(90deg, rgba(42, 74, 102, .16) 0 1px, transparent 1px 88px);
  color: var(--fog);
  font-family: var(--font-ui);
  font-size: 16px;
  font-weight: 400;
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

h1, h2, h3, h4 {
  font-family: var(--font-display);
  font-weight: 800;
  line-height: 1.22;
  letter-spacing: .01em;
  color: var(--fog);
}
h1 { font-size: clamp(2.1rem, 5.4vw, 4.4rem); font-weight: 900; line-height: 1.1; }
h2 { font-size: clamp(1.6rem, 3.4vw, 2.6rem); }
h3 { font-size: clamp(1.15rem, 2vw, 1.5rem); }

p { color: var(--fog-80); }

strong { color: var(--fog); font-weight: 700; }

small { font-size: .82em; }

/* ---------- 4. 焦点与无障碍 ---------- */
:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 2px;
  border-radius: var(--radius);
}

.skip-link {
  position: fixed;
  top: 10px;
  left: 10px;
  z-index: 400;
  padding: 12px 20px;
  background: var(--cyan);
  color: var(--ink);
  font-family: var(--font-ui);
  font-size: 14px;
  font-weight: 700;
  letter-spacing: .06em;
  border-radius: var(--radius);
  transform: translateY(-180%);
  transition: transform .22s ease;
}
.skip-link:focus { transform: translateY(0); }

/* ---------- 5. 头部框架 ---------- */
.frame-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: linear-gradient(180deg, rgba(7, 20, 38, .99) 0%, rgba(11, 34, 57, .95) 100%);
  border-bottom: 1px solid var(--line);
  color: var(--fog);
}

.frame-header__rail {
  position: relative;
  display: flex;
  align-items: center;
  gap: clamp(12px, 2vw, 32px);
  width: 100%;
  max-width: var(--maxw);
  min-height: var(--header-h);
  margin-inline: auto;
  padding: 0 var(--pad-x);
}

.frame-header__rail::after {
  content: "";
  position: absolute;
  left: var(--pad-x);
  right: var(--pad-x);
  bottom: 0;
  height: 1px;
  background: var(--tick-line);
  opacity: .55;
  pointer-events: none;
}

/* 品牌 */
.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  flex: 0 0 auto;
  padding: 6px 0;
  color: var(--fog);
}

.brand__mark {
  position: relative;
  flex: none;
  width: 30px;
  height: 30px;
  border: 1px solid var(--cyan);
  background: rgba(52, 245, 225, .06);
}
.brand__mark::before {
  content: "";
  position: absolute;
  inset: 6px;
  background: var(--cyan);
  clip-path: polygon(0 100%, 100% 0, 100% 100%);
  opacity: .9;
}
.brand__mark::after {
  content: "";
  position: absolute;
  inset: -1px;
  border-top: 1px solid var(--line);
  border-right: 1px solid var(--line);
}

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

.brand__name {
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(17px, 1.8vw, 21px);
  letter-spacing: .02em;
  color: var(--fog);
}

.brand__tag {
  margin-top: 3px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .1em;
  color: var(--fog-38);
  white-space: nowrap;
}

/* 主导航 */
.nav {
  flex: 1 1 auto;
  display: flex;
  justify-content: center;
}

.nav__list {
  display: flex;
  align-items: stretch;
  gap: 0;
  margin: 0;
  padding: 0;
  list-style: none;
}

.nav__item { position: relative; }

.nav__link {
  display: inline-flex;
  align-items: baseline;
  gap: 6px;
  min-height: 44px;
  padding: 13px clamp(8px, 1vw, 14px);
  color: var(--fog-62);
  font-family: var(--font-ui);
  font-size: 14px;
  font-weight: 600;
  letter-spacing: .02em;
  white-space: nowrap;
  transition: color .18s ease, background-color .18s ease, box-shadow .18s ease;
}

.nav__num {
  font-family: var(--font-mono);
  font-size: 10px;
  line-height: 1;
  letter-spacing: 0;
  color: var(--line);
  transition: color .18s ease;
}

.nav__label { white-space: nowrap; }

.nav__link:hover {
  color: var(--fog);
  background: rgba(27, 53, 80, .58);
}
.nav__link:hover .nav__num { color: var(--cyan); }

.nav__link[aria-current="page"] {
  color: var(--cyan);
  background: rgba(52, 245, 225, .07);
  box-shadow: inset 2px 0 0 var(--cyan);
}
.nav__link[aria-current="page"] .nav__num { color: var(--cyan); }

/* 头部动作区 */
.frame-header__actions {
  display: flex;
  align-items: center;
  gap: 10px;
  flex: 0 0 auto;
  margin-left: auto;
}

.switch-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  min-height: 36px;
  padding: 6px 12px;
  border: 1px solid var(--orange);
  border-radius: var(--radius);
  background: rgba(255, 122, 47, .09);
  color: var(--orange);
  font-family: var(--font-ui);
  font-size: 12.5px;
  font-weight: 700;
  letter-spacing: .04em;
  white-space: nowrap;
  transition: background-color .18s ease, color .18s ease;
}
.switch-link::before {
  content: "";
  width: 6px;
  height: 6px;
  flex: none;
  background: currentColor;
}
.switch-link:hover {
  background: var(--orange);
  color: var(--ink);
}

/* 移动端开合按钮 */
.nav-toggle {
  display: none;
  align-items: center;
  gap: 9px;
  min-height: 44px;
  min-width: 44px;
  padding: 0 12px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: rgba(27, 53, 80, .6);
  color: var(--fog);
  font-family: var(--font-ui);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: .1em;
  cursor: pointer;
  position: relative;
  z-index: 95;
}
.nav-toggle:hover { border-color: var(--cyan); color: var(--cyan); }

.nav-toggle__bars {
  display: grid;
  gap: 6px;
  width: 16px;
}
.nav-toggle__bars span {
  display: block;
  height: 1px;
  background: currentColor;
  transition: transform .2s ease;
}
.frame-header[data-open] .nav-toggle__bars span:first-child {
  transform: translateY(3.5px) rotate(45deg);
}
.frame-header[data-open] .nav-toggle__bars span:last-child {
  transform: translateY(-3.5px) rotate(-45deg);
}

.nav-toggle__label { line-height: 1; }

body.is-nav-open { overflow: hidden; }

/* ---------- 6. 页脚 ---------- */
.frame-footer {
  position: relative;
  margin-top: clamp(56px, 9vw, 120px);
  background:
    radial-gradient(900px 400px at 12% 0%, rgba(63, 216, 255, .09), transparent 66%),
    radial-gradient(700px 340px at 92% 10%, rgba(155, 123, 255, .08), transparent 70%),
    var(--ink-2);
  border-top: 1px solid var(--line);
  color: var(--fog);
}

.frame-footer::before {
  content: "";
  display: block;
  height: 5px;
  background: repeating-linear-gradient(90deg, var(--line) 0 1px, transparent 1px 16px);
  opacity: .85;
}

.frame-footer__inner {
  display: grid;
  grid-template-columns: minmax(0, 1.5fr) repeat(3, minmax(0, 1fr));
  gap: clamp(26px, 3vw, 48px);
  width: 100%;
  max-width: var(--maxw);
  margin-inline: auto;
  padding: clamp(34px, 5vw, 64px) var(--pad-x);
}

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

.footer-wordmark {
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(22px, 2.6vw, 30px);
  line-height: 1.2;
  letter-spacing: .02em;
  color: var(--fog);
}

.footer-sign {
  margin-top: 8px;
  font-size: 14px;
  color: var(--fog-62);
}

.footer-contact {
  display: grid;
  gap: 7px;
  margin: 20px 0 0;
  padding: 16px 0 0;
  list-style: none;
  border-top: 1px solid var(--line-soft);
}

.footer-contact__item {
  display: flex;
  align-items: baseline;
  gap: 12px;
  min-width: 0;
}

.footer-contact__key {
  flex: none;
  min-width: 42px;
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: .12em;
  color: var(--cyan);
}

.footer-contact__val {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: .01em;
  color: var(--fog-80);
  word-break: break-word;
  font-variant-numeric: tabular-nums;
}

.footer-contact__val--text {
  font-family: var(--font-ui);
  font-size: 13px;
  line-height: 1.7;
}

.footer-contact__item--note {
  margin-top: 6px;
}
.footer-contact__item--note .footer-contact__val {
  color: var(--fog-38);
  font-size: 12.5px;
}

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

.footer-col__title {
  padding-bottom: 12px;
  margin-bottom: 12px;
  border-bottom: 1px solid var(--line-soft);
  font-family: var(--font-ui);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: .18em;
  color: var(--fog-38);
}

.footer-col__list {
  display: grid;
  gap: 2px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.footer-link {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  min-height: 36px;
  padding: 4px 0;
  color: var(--fog-80);
  font-size: 14px;
  transition: color .18s ease;
}
.footer-link::before {
  content: "";
  flex: none;
  width: 6px;
  height: 1px;
  background: var(--line);
  transition: width .2s ease, background-color .2s ease;
}
.footer-link:hover { color: var(--cyan); }
.footer-link:hover::before { width: 16px; background: var(--cyan); }
.footer-link[aria-current="page"] { color: var(--cyan); }
.footer-link[aria-current="page"]::before { width: 16px; background: var(--cyan); }

.frame-footer__meta {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 10px 32px;
  width: 100%;
  max-width: var(--maxw);
  margin-inline: auto;
  padding: 18px var(--pad-x) 34px;
  border-top: 1px solid var(--line);
  font-size: 12.5px;
  color: var(--fog-38);
}

.footer-legal {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .03em;
  color: var(--fog-62);
  font-variant-numeric: tabular-nums;
}

.footer-service {
  margin: 0;
  max-width: 62ch;
  color: var(--fog-38);
}

/* ---------- 7. 容器与排版组件 ---------- */
.wrap {
  width: 100%;
  max-width: var(--maxw);
  margin-inline: auto;
  padding-inline: var(--pad-x);
}

.prose {
  max-width: 68ch;
  font-size: 16.5px;
  line-height: 1.85;
  color: var(--fog-80);
}
.prose p + p { margin-top: 1.1em; }
.prose a {
  color: var(--cyan);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
}
.prose a:hover { color: var(--sky); }
.prose ul,
.prose ol {
  margin: 1.1em 0;
  padding-left: 1.4em;
  list-style: disc;
}
.prose ol { list-style: decimal; }
.prose li + li { margin-top: .4em; }
.prose strong { color: var(--fog); }

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: .18em;
  color: var(--cyan);
}
.eyebrow::before {
  content: "";
  width: 22px;
  height: 1px;
  background: currentColor;
}

.section-head {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-end;
  justify-content: space-between;
  gap: 12px 28px;
  margin-bottom: clamp(20px, 3vw, 34px);
  padding-bottom: 16px;
  border-bottom: 1px solid var(--line-soft);
}

.section-title {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(1.6rem, 3.4vw, 2.6rem);
  line-height: 1.24;
  letter-spacing: .01em;
  color: var(--fog);
}

.section-sub {
  max-width: 52ch;
  font-size: 14.5px;
  line-height: 1.7;
  color: var(--fog-62);
}

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

/* ---------- 8. 按钮 ---------- */
.btn {
  --btn-fg: var(--ink);
  --btn-bg: var(--cyan);
  --btn-bd: var(--cyan);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  min-height: 46px;
  padding: 12px 22px;
  background: var(--btn-bg);
  border: 1px solid var(--btn-bd);
  border-radius: var(--radius);
  color: var(--btn-fg);
  font-family: var(--font-ui);
  font-size: 14px;
  font-weight: 700;
  letter-spacing: .06em;
  text-align: center;
  cursor: pointer;
  transition: transform .16s ease, background-color .18s ease, color .18s ease, border-color .18s ease;
}
.btn:hover { transform: translateY(-1px); }
.btn:active { transform: none; }

.btn--ghost {
  --btn-fg: var(--fog);
  --btn-bg: transparent;
  --btn-bd: var(--line);
}
.btn--ghost:hover {
  --btn-fg: var(--cyan);
  --btn-bd: var(--cyan);
  background: rgba(52, 245, 225, .08);
}

.btn--signal {
  --btn-fg: var(--orange);
  --btn-bg: transparent;
  --btn-bd: var(--orange);
}
.btn--signal:hover {
  --btn-fg: var(--ink);
  background: var(--orange);
}

.btn--block { width: 100%; }

/* ---------- 9. 标签 ---------- */
.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 3px 9px;
  border: 1px solid currentColor;
  border-radius: var(--radius);
  font-family: var(--font-mono);
  font-size: 11px;
  line-height: 1.65;
  letter-spacing: .08em;
  white-space: nowrap;
  font-variant-numeric: tabular-nums;
}
.tag--cyan { color: var(--cyan); background: rgba(52, 245, 225, .07); }
.tag--orange { color: var(--orange); background: rgba(255, 122, 47, .08); }
.tag--mint { color: var(--mint); background: rgba(99, 230, 166, .07); }
.tag--violet { color: var(--violet); background: rgba(155, 123, 255, .08); }
.tag--muted { color: var(--fog-38); background: transparent; }

/* ---------- 10. 面包屑 ---------- */
.crumbs {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  padding-top: 16px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .06em;
  color: var(--fog-38);
}
.crumbs a { color: var(--fog-62); transition: color .18s ease; }
.crumbs a:hover { color: var(--cyan); }
.crumbs__sep { opacity: .5; }
.crumbs [aria-current="page"] { color: var(--fog); }

/* ---------- 11. 网格与 Bento ---------- */
.grid {
  display: grid;
  gap: clamp(12px, 1.6vw, 20px);
}

.bento {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  gap: clamp(12px, 1.6vw, 20px);
}
.bento > * { grid-column: span 12; }

@media (min-width: 760px) {
  .bento > .c4 { grid-column: span 4; }
  .bento > .c5 { grid-column: span 5; }
  .bento > .c6 { grid-column: span 6; }
  .bento > .c7 { grid-column: span 7; }
  .bento > .c8 { grid-column: span 8; }
  .bento > .c12 { grid-column: span 12; }
}

/* ---------- 12. 卡片 ---------- */
.card {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 12px;
  padding: clamp(16px, 2vw, 26px);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: linear-gradient(180deg, rgba(27, 53, 80, .55) 0%, rgba(11, 34, 57, .78) 100%);
  overflow: hidden;
}
.card::before {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  height: 1px;
  background: linear-gradient(90deg, var(--cyan) 0%, rgba(63, 216, 255, .5) 38%, transparent 72%);
  opacity: .5;
  pointer-events: none;
}

.card__title {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(1.05rem, 1.7vw, 1.32rem);
  line-height: 1.34;
  color: var(--fog);
}

.card__meta {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .08em;
  color: var(--fog-38);
  font-variant-numeric: tabular-nums;
}

/* ---------- 13. 数据块 ---------- */
.stat {
  display: grid;
  gap: 2px;
  min-width: 0;
}
.stat__value {
  font-family: var(--font-mono);
  font-weight: 600;
  font-size: clamp(1.5rem, 3vw, 2.3rem);
  line-height: 1.1;
  letter-spacing: -.02em;
  color: var(--fog);
  font-variant-numeric: tabular-nums;
}
.stat__label {
  font-family: var(--font-ui);
  font-size: 11.5px;
  letter-spacing: .14em;
  color: var(--fog-38);
}

/* ---------- 14. 图片容器基础规则 ---------- */
.media {
  position: relative;
  display: block;
  overflow: hidden;
  isolation: isolate;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background:
    linear-gradient(150deg, rgba(63, 216, 255, .18) 0%, transparent 55%),
    linear-gradient(205deg, rgba(155, 123, 255, .16) 0%, transparent 62%),
    var(--slate);
}
.media::after {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 2;
  pointer-events: none;
  background:
    repeating-linear-gradient(90deg, rgba(42, 74, 102, .45) 0 1px, transparent 1px 40px),
    repeating-linear-gradient(180deg, rgba(42, 74, 102, .45) 0 1px, transparent 1px 40px);
  opacity: .5;
}
.media img {
  position: relative;
  z-index: 1;
  width: 100%;
  height: 100%;
  object-fit: cover;
}
.media--16x9 { aspect-ratio: 16 / 9; }
.media--4x3 { aspect-ratio: 4 / 3; }
.media--1x1 { aspect-ratio: 1 / 1; }
.media--3x4 { aspect-ratio: 3 / 4; }
.media--wide { aspect-ratio: 21 / 9; }

.media__caption {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  z-index: 3;
  margin: 0;
  padding: 8px 12px;
  border-top: 1px solid var(--line);
  background: rgba(7, 20, 38, .78);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .06em;
  color: var(--fog-62);
}

/* ---------- 15. 章节目录跟随 ---------- */
.toc {
  position: sticky;
  top: calc(var(--header-h) + 24px);
  display: grid;
  gap: 10px;
  align-content: start;
}
.toc__title {
  font-family: var(--font-ui);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: .18em;
  color: var(--fog-38);
}
.toc__list {
  display: grid;
  gap: 2px;
  margin: 0;
  padding: 0;
  list-style: none;
}
.toc__link {
  position: relative;
  display: block;
  padding: 7px 0 7px 14px;
  border-left: 1px solid var(--line);
  color: var(--fog-38);
  font-size: 13.5px;
  line-height: 1.55;
  transition: color .18s ease, border-color .18s ease;
}
.toc__link::before {
  content: "";
  position: absolute;
  left: -1px;
  top: 0;
  bottom: 0;
  width: 2px;
  background: var(--cyan);
  transform: scaleY(0);
  transform-origin: 50% 0;
  transition: transform .26s cubic-bezier(.3, .8, .4, 1);
}
.toc__link:hover { color: var(--fog-80); }
.toc__link.is-current {
  color: var(--cyan);
  border-left-color: transparent;
}
.toc__link.is-current::before { transform: scaleY(1); }

/* ---------- 16. 滚动进度与返回顶部 ---------- */
.scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  z-index: 300;
  pointer-events: none;
}
.scroll-progress__bar {
  display: block;
  width: 100%;
  height: 100%;
  transform: scaleX(0);
  transform-origin: 0 50%;
  background: linear-gradient(90deg, var(--cyan) 0%, var(--sky) 58%, var(--orange) 100%);
  will-change: transform;
}

.to-top {
  position: fixed;
  right: clamp(14px, 2vw, 28px);
  bottom: clamp(14px, 2vw, 28px);
  z-index: 290;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  min-width: 44px;
  min-height: 44px;
  padding: 0 15px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: rgba(11, 34, 57, .94);
  color: var(--fog);
  font-family: var(--font-ui);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: .12em;
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transform: translateY(10px);
  transition: opacity .22s ease, transform .22s ease, visibility .22s ease, border-color .2s ease, color .2s ease;
}
.to-top.is-on {
  opacity: 1;
  visibility: visible;
  transform: none;
}
.to-top:hover { border-color: var(--cyan); color: var(--cyan); }

.to-top__arrow {
  width: 8px;
  height: 8px;
  margin-top: 3px;
  border-left: 1px solid currentColor;
  border-top: 1px solid currentColor;
  transform: rotate(45deg);
}
.to-top__label { line-height: 1; }

/* ---------- 17. 入场显现 ---------- */
html.js-reveal [data-reveal] {
  opacity: 0;
  transform: translateY(14px);
  transition: opacity .5s ease, transform .5s ease;
}
html.js-reveal [data-reveal].is-visible {
  opacity: 1;
  transform: none;
}

/* ---------- 18. 响应式：头部抽屉 ---------- */
@media (max-width: 1080px) {
  .nav-toggle { display: inline-flex; }

  .nav {
    position: fixed;
    top: 0;
    right: 0;
    bottom: 0;
    z-index: 90;
    display: block;
    width: min(340px, 86vw);
    padding: calc(var(--header-h) + 18px) 16px 28px;
    border-left: 1px solid var(--line);
    background:
      linear-gradient(180deg, rgba(11, 34, 57, .99) 0%, rgba(7, 20, 38, .99) 100%);
    box-shadow: -24px 0 60px rgba(0, 0, 0, .45), 0 0 0 100vmax rgba(7, 20, 38, 0);
    transform: translateX(102%);
    visibility: hidden;
    overflow-y: auto;
    transition: transform .28s cubic-bezier(.3, .8, .4, 1), box-shadow .28s ease, visibility .28s ease;
  }

  .frame-header[data-open] .nav {
    transform: none;
    visibility: visible;
    box-shadow: -24px 0 60px rgba(0, 0, 0, .5), 0 0 0 100vmax rgba(7, 20, 38, .74);
  }

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

  .nav__link {
    justify-content: space-between;
    width: 100%;
    min-height: 50px;
    padding: 15px 12px;
    border-bottom: 1px solid var(--line-soft);
    font-size: 15px;
  }

  .nav__link[aria-current="page"] { box-shadow: inset 3px 0 0 var(--cyan); }
}

@media (max-width: 980px) {
  .frame-footer__inner { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .footer-brand { grid-column: 1 / -1; }
}

@media (max-width: 900px) {
  .switch-link {
    padding: 5px 9px;
    font-size: 11.5px;
    letter-spacing: .01em;
  }
  .brand__tag { font-size: 10px; letter-spacing: .06em; }
}

@media (max-width: 760px) {
  :root { --header-h: 66px; }
  html { scroll-padding-top: 88px; }

  .brand__tag { display: none; }
  .brand__mark { width: 26px; height: 26px; }

  .frame-footer__meta {
    flex-direction: column;
    gap: 8px;
  }
  .footer-service { max-width: none; }
}

@media (max-width: 620px) {
  .switch-link { display: none; }
  .to-top__label { display: none; }
  .to-top { padding: 0; width: 46px; justify-content: center; }
  .frame-footer__inner { grid-template-columns: 1fr; }
  .footer-contact__item { gap: 8px; }
  .footer-contact__key { min-width: 38px; }
}

@media (max-width: 400px) {
  .brand__name { font-size: 16px; }
  .nav-toggle { padding: 0 10px; }
}

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

  *,
  *::before,
  *::after {
    animation-duration: .01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .01ms !important;
    scroll-behavior: auto !important;
  }

  html.js-reveal [data-reveal] {
    opacity: 1;
    transform: none;
  }

  .to-top { transform: none; }
}

/* ---------- 20. 打印 ---------- */
@media print {
  .frame-header,
  .frame-footer,
  .scroll-progress,
  .to-top,
  .skip-link { display: none !important; }

  body {
    background: #FFFFFF;
    color: #111111;
  }
  h1, h2, h3, h4, p, .prose { color: #111111; }
  a { text-decoration: underline; }
}