/* ============================================================
   诺亚体育看台 · 共享样式表 /assets/site.css
   深木基底 + 技术蓝图网格 + 草皮绿 / 信号橙 / 电子蓝脉冲
   ============================================================ */

/* ---------- 1. 重置 ---------- */
*,
*::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, figcaption, blockquote, dl, dd {
  margin: 0;
  padding: 0;
}

ul, ol { list-style: none; }

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

img { height: auto; }

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

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

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

/* ---------- 2. 变量 ---------- */
:root {
  --wood-base: #14100C;
  --wood-layer: #1E1713;
  --wood-high: #2C221B;
  --turf-deep: #14332A;
  --turf-mid: #1F6B4F;
  --grass: #3E9E72;
  --signal: #FF7A1A;
  --electric: #3FA9F5;
  --paper: #F2EDE6;
  --ash: #A79C90;

  --line: rgba(242, 237, 230, 0.12);
  --line-soft: rgba(242, 237, 230, 0.06);
  --line-strong: rgba(242, 237, 230, 0.24);

  --r-lg: 28px;
  --r-md: 18px;
  --r-sm: 12px;
  --pill: 999px;

  --shell: min(1320px, 92vw);
  --gutter: clamp(16px, 4vw, 40px);

  --font-head: "Archivo Narrow", "Noto Sans SC", "PingFang SC", "Hiragino Sans GB", "Source Han Sans SC", "Microsoft YaHei", system-ui, sans-serif;
  --font-body: "Noto Sans SC", "PingFang SC", "Hiragino Sans GB", "Source Han Sans SC", "Microsoft YaHei", system-ui, -apple-system, sans-serif;
  --font-mono: "IBM Plex Mono", "Roboto Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;

  --ease: cubic-bezier(0.22, 1, 0.36, 1);
  --shadow-lift: 0 26px 60px -34px rgba(0, 0, 0, 0.95);
}

/* ---------- 3. 基础排版 ---------- */
body {
  min-height: 100vh;
  background-color: var(--wood-base);
  background-image:
    linear-gradient(to right, var(--line-soft) 1px, transparent 1px),
    linear-gradient(to bottom, var(--line-soft) 1px, transparent 1px),
    radial-gradient(115% 75% at 88% -12%, rgba(31, 107, 79, 0.30), transparent 62%),
    radial-gradient(85% 60% at -5% 0%, rgba(63, 169, 245, 0.10), transparent 58%);
  background-size: 88px 88px, 88px 88px, cover, cover;
  background-repeat: repeat, repeat, no-repeat, no-repeat;
  color: var(--paper);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.75;
  letter-spacing: 0.005em;
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-head);
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1.1;
  color: var(--paper);
}

h1 { font-size: clamp(34px, 6vw, 88px); }
h2 { font-size: clamp(26px, 3.6vw, 48px); }
h3 { font-size: clamp(20px, 2.2vw, 28px); }
h4 { font-size: clamp(17px, 1.6vw, 21px); }

p { line-height: 1.78; }

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

::selection {
  background: rgba(255, 122, 26, 0.35);
  color: var(--paper);
}

/* ---------- 4. 工具类 ---------- */
.shell {
  width: var(--shell);
  margin-inline: auto;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: -1px;
  padding: 0;
  overflow: hidden;
  clip: rect(0 0 0 0);
  clip-path: inset(50%);
  white-space: nowrap;
  border: 0;
}

.num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-weight: 500;
  letter-spacing: -0.01em;
}

.label {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--ash);
}

.prose {
  max-width: 38em;
  color: rgba(242, 237, 230, 0.86);
}

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

.lede {
  max-width: 34em;
  font-size: clamp(17px, 1.5vw, 20px);
  line-height: 1.85;
  color: rgba(242, 237, 230, 0.78);
}

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

/* ---------- 5. 焦点与动效基线 ---------- */
:focus-visible {
  outline: 2px solid var(--signal);
  outline-offset: 3px;
  border-radius: 6px;
}

#main-content { display: block; }
#main-content:focus { outline: none; }

[data-reveal] {
  opacity: 0;
  transform: translateY(12px);
  transition: opacity 0.36s var(--ease), transform 0.36s var(--ease);
}

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

[data-filter-item][hidden] { display: none !important; }

/* ---------- 6. 按钮族 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5em;
  padding: 0.72em 1.35em;
  border: 1px solid transparent;
  border-radius: var(--pill);
  font-size: 14px;
  font-weight: 500;
  letter-spacing: 0.02em;
  white-space: nowrap;
  transition: background-color 0.18s var(--ease), color 0.18s var(--ease),
              border-color 0.18s var(--ease), transform 0.18s var(--ease);
}

.btn:hover { transform: translateY(-1px); }

.btn--solid {
  background: var(--signal);
  color: #1A1004;
  font-weight: 700;
}

.btn--solid:hover { background: #ff8f3d; }

.btn--ghost {
  border-color: var(--line-strong);
  color: var(--paper);
}

.btn--ghost:hover {
  border-color: var(--grass);
  color: var(--grass);
  background: rgba(62, 158, 114, 0.10);
}

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

.btn--line:hover {
  background: rgba(63, 169, 245, 0.10);
}

/* ---------- 7. 胶囊标签与筛选 ---------- */
.chip-group {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.chip {
  display: inline-flex;
  align-items: center;
  gap: 0.45em;
  padding: 0.42em 0.95em;
  border: 1px solid var(--line);
  border-radius: var(--pill);
  background: var(--wood-layer);
  font-size: 13px;
  color: var(--ash);
  letter-spacing: 0.02em;
  transition: color 0.18s var(--ease), border-color 0.18s var(--ease),
              background-color 0.18s var(--ease);
}

.chip:hover {
  color: var(--paper);
  border-color: var(--line-strong);
}

.chip[aria-pressed="true"] {
  background: var(--turf-deep);
  border-color: var(--grass);
  color: var(--paper);
}

.chip[aria-pressed="true"]::before {
  content: "";
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--signal);
}

[data-filter-status] {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.12em;
  color: var(--ash);
}

.tag {
  display: inline-block;
  padding: 0.2em 0.7em;
  border: 1px solid var(--line-strong);
  border-radius: var(--pill);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--ash);
  white-space: nowrap;
}

.tag--green {
  color: var(--grass);
  border-color: rgba(62, 158, 114, 0.5);
  background: rgba(62, 158, 114, 0.10);
}

.tag--orange {
  color: var(--signal);
  border-color: rgba(255, 122, 26, 0.5);
  background: rgba(255, 122, 26, 0.10);
}

.tag--blue {
  color: var(--electric);
  border-color: rgba(63, 169, 245, 0.5);
  background: rgba(63, 169, 245, 0.10);
}

/* ---------- 8. 面包屑 ---------- */
.crumbs {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--ash);
}

.crumbs__link { color: var(--ash); transition: color 0.18s var(--ease); }
.crumbs__link:hover { color: var(--electric); }
.crumbs__sep { opacity: 0.5; }
.crumbs__current { color: var(--paper); }

/* ---------- 9. 区块与网格 ---------- */
.section { padding: clamp(48px, 7vw, 110px) 0; }
.section--turf { background: var(--turf-deep); }
.section--layer { background: var(--wood-layer); }
.section--tight { padding: clamp(32px, 4vw, 64px) 0; }

.section__head {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-end;
  justify-content: space-between;
  gap: 18px 32px;
  margin-bottom: clamp(24px, 3.4vw, 48px);
}

.section__kicker {
  display: block;
  margin-bottom: 12px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--ash);
}

.section__title { font-size: clamp(28px, 4.4vw, 56px); }

.grid { display: grid; gap: clamp(16px, 2.4vw, 28px); }
.grid--2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid--3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.grid--4 { grid-template-columns: repeat(4, minmax(0, 1fr)); }

/* ---------- 10. 资料卡 ---------- */
.slab {
  background: linear-gradient(180deg, var(--wood-layer), rgba(30, 23, 19, 0.82));
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
  padding: clamp(20px, 3vw, 34px);
  transition: border-color 0.18s var(--ease), transform 0.24s var(--ease),
              background-color 0.18s var(--ease);
}

.slab:hover {
  border-color: var(--line-strong);
  transform: translateY(-2px);
}

.slab__head {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 18px;
}

.slab__title { font-family: var(--font-head); font-size: clamp(18px, 2vw, 22px); }

.slab__meta {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--ash);
}

/* ---------- 11. 索引行 ---------- */
.index-row {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  align-items: center;
  gap: clamp(12px, 2vw, 28px);
  padding: clamp(14px, 2vw, 22px) 0;
  border-top: 1px solid var(--line);
  transition: background-color 0.18s var(--ease);
}

.index-row:last-child { border-bottom: 1px solid var(--line); }

.index-row__num {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--ash);
}

.index-row__title {
  font-family: var(--font-head);
  font-size: clamp(18px, 2.4vw, 26px);
  letter-spacing: -0.02em;
}

.index-row__arrow {
  font-family: var(--font-mono);
  color: var(--ash);
  transition: transform 0.24s var(--ease), color 0.18s var(--ease);
}

.index-row:hover .index-row__title { color: var(--grass); }
.index-row:hover .index-row__arrow { color: var(--signal); transform: translateX(6px); }

/* ---------- 12. 横向刻度带 ---------- */
.ruler {
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  padding: 18px 0;
}

.ruler__track {
  display: flex;
  align-items: stretch;
  gap: 0;
  overflow-x: auto;
  scrollbar-width: thin;
}

.ruler__node {
  position: relative;
  flex: 1 0 auto;
  min-width: 120px;
  padding: 14px 18px 14px 18px;
  border-left: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--ash);
}

.ruler__node::before {
  content: "";
  position: absolute;
  left: -3px;
  top: 18px;
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--wood-high);
  transition: background-color 0.24s var(--ease), box-shadow 0.24s var(--ease);
}

.ruler__node[data-active] {
  color: var(--paper);
  background: rgba(31, 107, 79, 0.22);
}

.ruler__node[data-active]::before {
  background: var(--signal);
  box-shadow: 0 0 0 4px rgba(255, 122, 26, 0.18);
}

/* ---------- 13. 图片容器（页面阶段放占位图） ---------- */
.media-frame {
  position: relative;
  display: block;
  overflow: hidden;
  isolation: isolate;
  aspect-ratio: 16 / 10;
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
  background-image:
    linear-gradient(140deg, var(--turf-deep), var(--wood-layer) 58%, #0E0B08),
    linear-gradient(to right, rgba(242, 237, 230, 0.05) 1px, transparent 1px);
  background-size: cover, 44px 44px;
}

.media-frame img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  filter: saturate(0.92) contrast(1.05) brightness(0.92);
}

.media-frame::after {
  content: "";
  position: absolute;
  inset: 10px;
  border: 1px solid rgba(242, 237, 230, 0.14);
  border-radius: calc(var(--r-lg) - 10px);
  pointer-events: none;
}

.media-frame--wide { aspect-ratio: 21 / 9; }
.media-frame--tall { aspect-ratio: 4 / 5; }
.media-frame--square { aspect-ratio: 1 / 1; }

.media-frame__caption {
  position: absolute;
  left: 20px;
  bottom: 16px;
  z-index: 2;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--ash);
}

/* ---------- 14. 头部 ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 60;
  background: rgba(20, 16, 12, 0.94);
  -webkit-backdrop-filter: blur(10px);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
  transition: background-color 0.24s var(--ease), border-color 0.24s var(--ease);
}

.site-header__inner {
  position: relative;
  width: var(--shell);
  margin-inline: auto;
}

.skip-link {
  position: absolute;
  left: var(--gutter);
  top: -80px;
  z-index: 100;
  padding: 0.6em 1.1em;
  border-radius: var(--pill);
  background: var(--signal);
  color: #1A1004;
  font-size: 14px;
  font-weight: 700;
  transition: top 0.18s var(--ease);
}

.skip-link:focus { top: 10px; }

.scroll-rail {
  position: absolute;
  left: 0;
  bottom: -1px;
  z-index: 5;
  width: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--turf-mid), var(--signal));
  transition: width 0.1s linear;
}

.masthead {
  display: grid;
  grid-template-columns: minmax(0, 1.02fr) minmax(0, 1fr);
  align-items: start;
  gap: clamp(20px, 4vw, 64px);
  padding: clamp(20px, 2.6vw, 34px) 0 clamp(16px, 2.2vw, 26px);
  transition: padding 0.24s var(--ease);
}

.masthead__brand { min-width: 0; }

.brand {
  display: inline-flex;
  align-items: center;
  gap: 14px;
}

.brand__mark {
  display: grid;
  align-content: center;
  gap: 3px;
  width: 40px;
  height: 40px;
  padding: 9px 8px;
  border: 1px solid var(--line-strong);
  border-radius: var(--r-sm);
  background: var(--turf-deep);
}

.brand__mark-line {
  display: block;
  height: 2px;
  border-radius: 2px;
  background: var(--grass);
}

.brand__mark-line:nth-child(1) { width: 100%; }
.brand__mark-line:nth-child(2) { width: 70%; background: var(--signal); }
.brand__mark-line:nth-child(3) { width: 45%; background: var(--electric); }

.brand__text { display: flex; flex-direction: column; }

.brand__name {
  font-family: var(--font-head);
  font-size: 21px;
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--paper);
}

.brand__latin {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--ash);
}

.masthead__statement {
  max-width: 30em;
  margin-top: 12px;
  font-size: 14px;
  line-height: 1.7;
  color: rgba(242, 237, 230, 0.70);
}

.masthead__meta {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 16px;
  min-width: 0;
}

.stat-strip {
  display: flex;
  flex-wrap: wrap;
  gap: clamp(14px, 2.4vw, 34px);
}

.stat-strip__item {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 2px;
  padding-left: 14px;
}

.stat-strip__item::before {
  content: "";
  position: absolute;
  left: 0;
  top: 6px;
  bottom: 6px;
  width: 1px;
  background: var(--line-strong);
}

.stat-strip__num {
  font-family: var(--font-mono);
  font-size: 22px;
  font-weight: 500;
  line-height: 1.1;
  letter-spacing: -0.02em;
  color: var(--paper);
  font-variant-numeric: tabular-nums;
}

.stat-strip__item:nth-child(1) .stat-strip__num { color: var(--grass); }
.stat-strip__item:nth-child(2) .stat-strip__num { color: var(--electric); }

.stat-strip__label {
  font-size: 11px;
  letter-spacing: 0.06em;
  color: var(--ash);
}

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

.masthead__mail {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.06em;
  color: rgba(167, 156, 144, 0.85);
}

.navbar {
  position: relative;
  display: flex;
  align-items: center;
  gap: clamp(12px, 2vw, 28px);
  min-height: 56px;
  border-top: 1px solid var(--line);
}

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

.nav__list {
  display: flex;
  flex-wrap: wrap;
  gap: clamp(6px, 1.4vw, 22px);
  counter-reset: nav;
}

.nav__item { counter-increment: nav; }

.nav__link {
  position: relative;
  display: inline-flex;
  align-items: baseline;
  gap: 8px;
  padding: 18px 2px;
  font-size: 15px;
  color: rgba(242, 237, 230, 0.66);
  transition: color 0.18s var(--ease);
}

.nav__link::before {
  content: counter(nav, decimal-leading-zero);
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.1em;
  color: rgba(167, 156, 144, 0.6);
  transition: color 0.18s var(--ease);
}

.nav__link::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 10px;
  height: 2px;
  border-radius: 2px;
  background: var(--grass);
  transform: scaleX(0);
  transform-origin: left center;
  transition: transform 0.24s var(--ease), background-color 0.18s var(--ease);
}

.nav__link:hover { color: var(--paper); }
.nav__link:hover::after { transform: scaleX(1); }

.nav__link[aria-current="page"] { color: var(--paper); font-weight: 500; }
.nav__link[aria-current="page"]::after { transform: scaleX(1); background: var(--signal); }
.nav__link[aria-current="page"]::before { color: var(--signal); }

.navbar__coord {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.18em;
  white-space: nowrap;
  color: rgba(167, 156, 144, 0.55);
}

.nav-toggle {
  display: none;
  align-items: center;
  gap: 10px;
  margin: 10px 0;
  padding: 10px 16px;
  border: 1px solid var(--line-strong);
  border-radius: var(--pill);
  color: var(--paper);
}

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

.nav-toggle__bars span {
  display: block;
  height: 1.5px;
  border-radius: 2px;
  background: var(--paper);
  transition: transform 0.2s var(--ease), opacity 0.2s var(--ease);
}

.nav-toggle__label {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
}

/* 头部滚动压缩态 */
.site-header.is-condensed .masthead { padding: 10px 0 8px; }
.site-header.is-condensed .masthead__statement { display: none; }
.site-header.is-condensed .masthead__mail { display: none; }

/* ---------- 15. 页脚 ---------- */
.site-footer {
  margin-top: clamp(60px, 9vw, 140px);
  border-top: 1px solid var(--line-strong);
  background-image: linear-gradient(180deg, var(--wood-layer), #100D0A 72%);
  color: rgba(242, 237, 230, 0.8);
}

.site-footer__inner {
  width: var(--shell);
  margin-inline: auto;
  padding: clamp(40px, 5vw, 80px) 0 clamp(24px, 3vw, 40px);
}

.footer-index {
  display: grid;
  grid-template-columns: minmax(0, 1.5fr) repeat(3, minmax(0, 1fr));
  gap: clamp(24px, 3.4vw, 56px);
}

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

.footer-brand__name {
  display: block;
  font-family: var(--font-head);
  font-size: 22px;
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--paper);
}

.footer-brand__latin {
  display: block;
  margin-top: 4px;
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.22em;
  color: var(--ash);
}

.footer-brand__line {
  max-width: 26em;
  margin-top: 14px;
  font-size: 14px;
  line-height: 1.75;
  color: rgba(242, 237, 230, 0.62);
}

.footer-col__title {
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--ash);
}

.footer-col__list {
  display: grid;
  gap: 10px;
  margin-top: 16px;
}

.footer-col__link {
  font-size: 14px;
  color: rgba(242, 237, 230, 0.74);
  transition: color 0.18s var(--ease);
}

.footer-col__link:hover { color: var(--grass); }

.contact-strip {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 18px 28px;
  margin-top: clamp(32px, 4vw, 56px);
  padding: clamp(18px, 2.6vw, 30px);
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
  background: rgba(20, 16, 12, 0.6);
}

.contact-strip__item {
  display: flex;
  flex-direction: column;
  gap: 4px;
  min-width: 0;
}

.contact-strip__label {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--ash);
}

.contact-strip__value {
  font-size: 15px;
  color: var(--paper);
  overflow-wrap: anywhere;
}

.contact-strip__note {
  grid-column: 1 / -1;
  margin-top: 4px;
  padding-top: 14px;
  border-top: 1px dashed var(--line);
  font-size: 13px;
  color: rgba(242, 237, 230, 0.55);
}

.footer-legal {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 12px 28px;
  margin-top: clamp(24px, 3vw, 40px);
  padding-top: 20px;
  border-top: 1px solid var(--line);
}

.footer-legal__line {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  color: rgba(167, 156, 144, 0.8);
}

.to-top {
  padding: 0.5em 1.1em;
  border: 1px solid var(--line-strong);
  border-radius: var(--pill);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  color: var(--ash);
  opacity: 0;
  visibility: hidden;
  transform: translateY(6px);
  transition: opacity 0.24s var(--ease), transform 0.24s var(--ease),
              color 0.18s var(--ease), border-color 0.18s var(--ease);
}

.to-top.is-active { opacity: 1; visibility: visible; transform: none; }
.to-top:hover { color: var(--signal); border-color: var(--signal); }

/* ---------- 16. 响应式 ---------- */
@media (min-width: 901px) {
  .masthead__meta { align-items: flex-end; }
}

@media (min-width: 760px) {
  .contact-strip__item--wide { grid-column: span 2; }
}

@media (max-width: 1100px) {
  .navbar__coord { display: none; }
}

@media (max-width: 1024px) {
  .grid--4 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .grid--3 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (max-width: 960px) {
  .masthead {
    grid-template-columns: minmax(0, 1fr);
    gap: 18px;
    padding: 18px 0 16px;
  }

  .site-header.is-condensed .masthead { padding: 12px 0 10px; }
  .site-header.is-condensed .masthead__statement { display: block; }

  .masthead__meta { align-items: flex-start; }

  .navbar { justify-content: space-between; }

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

  .nav {
    position: absolute;
    left: 0;
    right: 0;
    top: 100%;
    z-index: 70;
    max-height: 0;
    overflow: hidden;
    visibility: hidden;
    padding-inline: 4px;
    background: var(--wood-layer);
    border-top: 1px solid var(--line);
    border-bottom: 1px solid var(--line-strong);
    box-shadow: 0 30px 50px -30px #000;
    transition: max-height 0.3s var(--ease), visibility 0.3s var(--ease);
  }

  .nav[data-open] {
    max-height: min(72vh, 520px);
    overflow-y: auto;
    visibility: visible;
  }

  .nav__list {
    flex-direction: column;
    gap: 0;
    padding: 6px 0 14px;
  }

  .nav__item { border-bottom: 1px solid var(--line-soft); }

  .nav__link {
    width: 100%;
    padding: 15px 6px;
    font-size: 16px;
  }

  .nav__link::after { display: none; }
  .nav__link[aria-current="page"] { color: var(--signal); }
  .nav__link[aria-current="page"]::before { color: var(--signal); }

  .nav-toggle[aria-expanded="true"] .nav-toggle__bars span:nth-child(1) {
    transform: translateY(5.5px) 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(-5.5px) rotate(-45deg);
  }

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

@media (max-width: 680px) {
  body { font-size: 15.5px; }

  .grid--2,
  .grid--3,
  .grid--4 { grid-template-columns: minmax(0, 1fr); }

  .stat-strip { gap: 14px 22px; }
  .stat-strip__num { font-size: 19px; }

  .masthead__actions { width: 100%; }
  .masthead__actions .btn { flex: 1 1 auto; }

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

  .footer-legal { flex-direction: column; align-items: flex-start; }
  .to-top { align-self: flex-start; }
}

/* ---------- 17. 降低动效偏好 ---------- */
@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;
  }

  [data-reveal] { opacity: 1; transform: none; }
  .to-top { opacity: 1; visibility: visible; transform: none; }
}