/* ============================================================
   6686赛场 · /assets/site.css
   共享外壳 / 变量 / 排版 / 通用组件
   ============================================================ */

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

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

body { margin: 0; }

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

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

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

p { margin: 0; }

/* ---------- 2. Tokens ---------- */
:root {
  /* 品牌色板 */
  --ink:        #061B2E;
  --ink-2:      #0B2F4A;
  --ink-3:      #124A63;
  --lime:       #2BFF88;
  --lime-soft:  #B8FFD6;
  --coral:      #FF6B4A;
  --ice:        #F2FBFF;
  --mist:       #9DB9C9;
  --teal:       #37D6C0;
  --amber:      #FFC857;

  /* 语义 */
  --line:        rgba(157, 185, 201, 0.22);
  --line-strong: rgba(157, 185, 201, 0.46);
  --glass:       rgba(18, 74, 99, 0.42);
  --glass-line:  rgba(157, 185, 201, 0.30);

  /* 形状 */
  --radius-glass: 18px;
  --radius-solid: 4px;
  --slant: 6deg;

  /* 网格 */
  --shell: 1280px;
  --gutter: 48px;

  /* 字体 */
  --font-display: "HarmonyOS Sans SC", "Noto Sans SC", "Source Han Sans SC",
                  "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;
  --font-body:    "PingFang SC", "Microsoft YaHei", "Noto Sans SC",
                  system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-mono:    "JetBrains Mono", "IBM Plex Mono", ui-monospace,
                  SFMono-Regular, Menlo, Consolas, monospace;
}

/* ---------- 3. 中文排版与底色 ---------- */
body {
  min-height: 100vh;
  background-color: var(--ink);
  background-image:
    radial-gradient(1100px 620px at 10% -12%, rgba(43, 255, 136, 0.14), transparent 62%),
    radial-gradient(900px 520px at 104% 4%, rgba(55, 214, 192, 0.12), transparent 66%),
    radial-gradient(760px 480px at 50% 118%, rgba(255, 107, 74, 0.08), transparent 68%);
  background-attachment: fixed;
  color: var(--ice);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.65;
  letter-spacing: 0.01em;
}

h1, h2, h3, h4, h5, h6 {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 900;
  line-height: 1.14;
  letter-spacing: -0.02em;
  color: var(--ice);
}

h1 { font-size: clamp(34px, 4.6vw, 62px); letter-spacing: -0.03em; }
h2 { font-size: clamp(24px, 3vw, 38px); }
h3 { font-size: clamp(18px, 2vw, 24px); }

p { margin-bottom: 1em; }
p:last-child { margin-bottom: 0; }

a {
  color: var(--lime);
  text-decoration: none;
  transition: color 0.2s ease, border-color 0.2s ease, background-color 0.2s ease;
}

a:hover { color: var(--ice); }

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

::selection {
  background: var(--lime);
  color: var(--ink);
}

/* ---------- 4. 焦点可见 ---------- */
:focus-visible {
  outline: 2px solid var(--lime);
  outline-offset: 3px;
  border-radius: 2px;
}

/* ---------- 5. 工具类 ---------- */
.mono {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  letter-spacing: 0.02em;
}

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

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

.dot {
  display: inline-block;
  width: 6px;
  height: 6px;
  margin-inline: 10px;
  border-radius: 50%;
  background: var(--lime);
  box-shadow: 0 0 10px rgba(43, 255, 136, 0.9);
  vertical-align: middle;
}

/* ---------- 6. Skip link ---------- */
.skip-link {
  position: absolute;
  left: 16px;
  top: -80px;
  z-index: 300;
  padding: 10px 20px;
  background: var(--lime);
  color: var(--ink);
  font-weight: 700;
  font-size: 14px;
  border-radius: var(--radius-solid);
  transition: top 0.2s ease;
}

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

/* ---------- 7. 头部 ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 80;
  background: rgba(6, 27, 46, 0.92);
  -webkit-backdrop-filter: blur(16px) saturate(150%);
  backdrop-filter: blur(16px) saturate(150%);
  border-bottom: 1px solid var(--line);
}

.header-top {
  background:
    linear-gradient(90deg,
      rgba(43, 255, 136, 0.12),
      rgba(55, 214, 192, 0.07) 46%,
      rgba(6, 27, 46, 0) 100%);
  border-bottom: 1px solid rgba(157, 185, 201, 0.14);
}

.header-top__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  min-height: 36px;
  padding-block: 6px;
}

.header-top__line {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--mist);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.utility-nav {
  display: flex;
  flex: 0 0 auto;
  align-items: center;
  gap: 6px;
}

.utility-nav a {
  display: inline-block;
  padding: 4px 11px;
  font-size: 12px;
  color: var(--mist);
  border: 1px solid transparent;
  border-radius: 999px;
  transition: color 0.2s ease, border-color 0.2s ease, background-color 0.2s ease;
}

.utility-nav a:hover {
  color: var(--ice);
  border-color: var(--line-strong);
  background: rgba(242, 251, 255, 0.06);
}

.header-main { position: relative; }

.header-main__inner {
  position: relative;
  display: flex;
  align-items: center;
  gap: 28px;
  min-height: 68px;
}

/* 品牌 */
.brand {
  display: inline-flex;
  flex: 0 0 auto;
  align-items: baseline;
  gap: 9px;
  color: var(--ice);
}

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

.brand__mark {
  display: inline-block;
  padding: 1px 9px 3px;
  font-family: var(--font-mono);
  font-size: 19px;
  font-weight: 700;
  letter-spacing: 0.04em;
  color: var(--ink);
  background: var(--lime);
  border-radius: 2px;
  transform: skewX(-6deg);
  box-shadow: 0 8px 22px -12px rgba(43, 255, 136, 0.9);
}

.brand__name {
  font-family: var(--font-display);
  font-size: 20px;
  font-weight: 900;
  letter-spacing: 0.04em;
}

/* 汉堡按钮 */
.nav-toggle {
  display: none;
  align-items: center;
  gap: 10px;
  padding: 9px 15px 9px 13px;
  background: rgba(43, 255, 136, 0.10);
  border: 1px solid rgba(43, 255, 136, 0.40);
  border-radius: 999px;
  color: var(--ice);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  cursor: pointer;
  transition: background-color 0.2s ease, border-color 0.2s ease;
}

.nav-toggle:hover {
  background: rgba(43, 255, 136, 0.18);
  border-color: var(--lime);
}

.nav-toggle__bars {
  position: relative;
  display: inline-block;
  width: 16px;
  height: 10px;
}

.nav-toggle__bars::before,
.nav-toggle__bars::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  height: 2px;
  background: var(--lime);
  transition: transform 0.2s ease, top 0.2s ease, bottom 0.2s ease;
}

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

.nav-toggle[aria-expanded="true"] .nav-toggle__bars::before {
  top: 4px;
  transform: rotate(45deg);
}

.nav-toggle[aria-expanded="true"] .nav-toggle__bars::after {
  bottom: 4px;
  transform: rotate(-45deg);
}

/* 主导航 */
.site-nav {
  display: flex;
  align-items: center;
  gap: 26px;
  margin-left: auto;
}

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

.site-nav__list a {
  position: relative;
  display: inline-block;
  padding: 8px 12px 9px;
  font-size: 15px;
  font-weight: 500;
  color: var(--ice);
  border-radius: 2px;
  transition: color 0.2s ease, background-color 0.2s ease;
}

.site-nav__list a::after {
  content: "";
  position: absolute;
  left: 12px;
  right: 12px;
  bottom: 2px;
  height: 2px;
  background: var(--lime);
  transform: scaleX(0);
  transform-origin: left center;
  transition: transform 0.2s ease;
}

.site-nav__list a:hover {
  color: var(--lime);
}

.site-nav__list a:hover::after { transform: scaleX(1); }

.site-nav__list a[aria-current="page"] {
  color: var(--ink);
  background: var(--lime-soft);
  font-weight: 700;
}

.site-nav__list a[aria-current="page"]::after {
  transform: scaleX(1);
  background: var(--ink-3);
}

.site-nav__utility { display: none; }

.site-nav__cta {
  display: inline-flex;
  flex: 0 0 auto;
  padding: 9px 16px;
  font-size: 13px;
}

/* 滚动进度线（JS 注入） */
.scroll-meter {
  position: absolute;
  left: 0;
  right: 0;
  bottom: -1px;
  height: 2px;
  overflow: hidden;
  background: rgba(157, 185, 201, 0.16);
  pointer-events: none;
}

.scroll-meter__bar {
  display: block;
  width: 100%;
  height: 100%;
  transform: scaleX(0);
  transform-origin: left center;
  background: linear-gradient(90deg, var(--lime), var(--teal) 58%, var(--coral));
}

/* ---------- 8. 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 22px;
  border: 1px solid transparent;
  border-radius: 2px;
  font-family: var(--font-body);
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.02em;
  line-height: 1.2;
  text-align: center;
  cursor: pointer;
  transition: background-color 0.2s ease, color 0.2s ease,
              border-color 0.2s ease, box-shadow 0.2s ease;
}

.btn--primary {
  background: var(--lime);
  color: var(--ink);
  box-shadow: 0 14px 32px -20px rgba(43, 255, 136, 0.95);
}

.btn--primary:hover {
  background: var(--ice);
  color: var(--ink);
  box-shadow: 0 16px 36px -18px rgba(43, 255, 136, 0.85);
}

.btn--ghost {
  background: transparent;
  color: var(--ice);
  border-color: var(--line-strong);
}

.btn--ghost:hover {
  color: var(--lime);
  border-color: var(--lime);
  background: rgba(43, 255, 136, 0.08);
}

.btn--coral {
  background: var(--coral);
  color: var(--ink);
  box-shadow: 0 14px 32px -22px rgba(255, 107, 74, 0.95);
}

.btn--coral:hover {
  background: #FF8767;
  color: var(--ink);
}

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

.btn--sm {
  padding: 8px 14px;
  font-size: 13px;
}

/* ---------- 9. 正文容器与章节节奏 ---------- */
.page-main { display: block; }

.section { padding-block: clamp(48px, 7vw, 96px); }

.section--band {
  background:
    linear-gradient(118deg,
      rgba(18, 74, 99, 0.55),
      rgba(6, 27, 46, 0.10) 62%);
  border-block: 1px solid var(--line);
}

.section__head {
  max-width: 62ch;
  margin-bottom: clamp(24px, 3vw, 40px);
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.18em;
  color: var(--lime);
}

.eyebrow::before {
  content: "";
  width: 26px;
  height: 1px;
  background: currentColor;
}

.section-num {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(44px, 7vw, 84px);
  font-weight: 700;
  line-height: 0.9;
  letter-spacing: -0.02em;
  color: rgba(43, 255, 136, 0.26);
  margin-bottom: 10px;
}

.prose {
  max-width: 68ch;
  color: rgba(242, 251, 255, 0.86);
  line-height: 1.75;
}

.prose h2,
.prose h3 {
  margin-top: 1.6em;
  margin-bottom: 0.55em;
  color: var(--ice);
}

.prose p { margin-bottom: 1.05em; }

.prose ul,
.prose ol {
  list-style: disc;
  padding-left: 1.35em;
  margin-bottom: 1.05em;
}

.prose li { margin-bottom: 0.4em; }

/* ---------- 10. 网格 ---------- */
.grid {
  display: grid;
  gap: clamp(16px, 2vw, 28px);
}

.grid--split {
  grid-template-columns: minmax(0, 5fr) minmax(0, 7fr);
}

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

/* ---------- 11. 面板与材质 ---------- */
.panel {
  padding: clamp(20px, 2.4vw, 32px);
  background: var(--ink-2);
  border: 1px solid var(--line);
  border-radius: var(--radius-solid);
}

.panel--glass {
  background: var(--glass);
  border: 1px solid var(--glass-line);
  border-radius: var(--radius-glass);
  -webkit-backdrop-filter: blur(12px);
  backdrop-filter: blur(12px);
  box-shadow: inset 0 1px 0 rgba(242, 251, 255, 0.14),
              0 24px 60px -34px rgba(0, 0, 0, 0.85);
}

/* ---------- 12. 标签 ---------- */
.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 3px 10px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--lime-soft);
  background: rgba(43, 255, 136, 0.14);
  border: 1px solid rgba(43, 255, 136, 0.36);
  border-radius: 999px;
}

.tag--coral {
  color: #FFB9A8;
  background: rgba(255, 107, 74, 0.15);
  border-color: rgba(255, 107, 74, 0.42);
}

.tag--teal {
  color: #A2F4E8;
  background: rgba(55, 214, 192, 0.15);
  border-color: rgba(55, 214, 192, 0.42);
}

.tag--amber {
  color: #FFDFA3;
  background: rgba(255, 200, 87, 0.15);
  border-color: rgba(255, 200, 87, 0.42);
}

/* ---------- 13. 数据条 ---------- */
.stat-row {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: var(--radius-solid);
  overflow: hidden;
}

.stat {
  padding: 16px 18px;
  background: rgba(11, 47, 74, 0.92);
}

.stat__value {
  display: block;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(22px, 2.4vw, 32px);
  font-weight: 700;
  line-height: 1.15;
  color: var(--ice);
}

.stat__label {
  display: block;
  margin-top: 6px;
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--mist);
}

.stat--coral .stat__value { color: var(--coral); }
.stat--lime  .stat__value { color: var(--lime); }
.stat--teal  .stat__value { color: var(--teal); }

/* ---------- 14. 分隔列表 ---------- */
.ruled-list li {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 6px 16px;
  padding: 14px 0;
  border-bottom: 1px solid var(--line);
}

.ruled-list li:first-child { border-top: 1px solid var(--line); }

/* ---------- 15. 图片容器 ---------- */
.media-frame {
  position: relative;
  display: block;
  overflow: hidden;
  aspect-ratio: 16 / 10;
  background:
    linear-gradient(140deg, var(--ink-3), var(--ink-2) 70%);
  border-radius: var(--radius-solid);
  box-shadow: inset 0 0 0 1px rgba(157, 185, 201, 0.24);
}

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

.media-frame--slant {
  border-radius: 0;
  clip-path: polygon(0 0, 100% 0, 100% 88%, 0 100%);
}

/* ---------- 16. 文字行动链接 ---------- */
.link-arrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding-bottom: 2px;
  font-size: 14px;
  font-weight: 600;
  color: var(--lime);
  border-bottom: 1px solid rgba(43, 255, 136, 0.38);
  transition: color 0.2s ease, border-color 0.2s ease, gap 0.2s ease;
}

.link-arrow::after {
  content: "→";
  font-family: var(--font-mono);
}

.link-arrow:hover {
  gap: 12px;
  color: var(--ice);
  border-color: var(--ice);
}

/* ---------- 17. 面包屑 ---------- */
.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.05em;
  color: var(--mist);
}

.breadcrumb a {
  color: var(--mist);
  border-bottom: 1px solid transparent;
}

.breadcrumb a:hover {
  color: var(--lime);
  border-color: var(--lime);
}

.breadcrumb li + li::before {
  content: "/";
  margin-right: 8px;
  color: rgba(157, 185, 201, 0.40);
}

/* ---------- 18. 返回顶部（JS 注入） ---------- */
.back-top {
  position: fixed;
  right: 20px;
  bottom: 20px;
  z-index: 90;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 16px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--ice);
  background: rgba(11, 47, 74, 0.94);
  border: 1px solid var(--line-strong);
  border-radius: 999px;
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transform: translateY(10px);
  transition: opacity 0.2s ease, visibility 0.2s ease,
              transform 0.2s ease, border-color 0.2s ease, color 0.2s ease;
}

.back-top[data-visible="true"] {
  opacity: 1;
  visibility: visible;
  transform: none;
}

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

/* ---------- 19. 页脚 ---------- */
.site-footer {
  margin-top: clamp(48px, 7vw, 96px);
  background:
    linear-gradient(180deg,
      rgba(11, 47, 74, 0.92),
      rgba(6, 27, 46, 1) 62%);
  border-top: 1px solid var(--line);
}

.footer-main {
  display: grid;
  grid-template-columns:
    minmax(0, 1.8fr) minmax(0, 1fr) minmax(0, 1fr) minmax(0, 1.6fr);
  gap: clamp(24px, 3vw, 48px);
  padding-block: clamp(40px, 5vw, 64px) clamp(28px, 3vw, 40px);
}

.footer-brand .brand { margin-bottom: 16px; }

.footer-brand__summary {
  max-width: 32ch;
  font-size: 14px;
  line-height: 1.75;
  color: var(--mist);
}

.footer-brand__meta {
  margin-top: 14px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: rgba(157, 185, 201, 0.72);
}

.footer-col__title {
  margin: 0 0 16px;
  padding-bottom: 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.16em;
  color: var(--lime);
  border-bottom: 1px solid var(--line);
}

.footer-list li + li { margin-top: 10px; }

.footer-list a {
  display: inline-block;
  font-size: 14px;
  color: var(--ice);
  border-bottom: 1px solid transparent;
  transition: color 0.2s ease, border-color 0.2s ease;
}

.footer-list a:hover {
  color: var(--lime);
  border-color: var(--lime);
}

.footer-contact {
  padding: 20px;
  background: var(--glass);
  border: 1px solid var(--glass-line);
  border-radius: var(--radius-glass);
  -webkit-backdrop-filter: blur(12px);
  backdrop-filter: blur(12px);
  box-shadow: inset 0 1px 0 rgba(242, 251, 255, 0.12);
}

.footer-contact__list li {
  display: flex;
  flex-wrap: wrap;
  gap: 4px 12px;
  padding: 9px 0;
  font-size: 13px;
  color: var(--ice);
  border-bottom: 1px dashed rgba(157, 185, 201, 0.22);
}

.footer-contact__list li:last-child { border-bottom: 0; }

.footer-contact__key {
  flex: 0 0 34px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.12em;
  color: var(--teal);
  padding-top: 2px;
}

.footer-note {
  margin-top: 12px;
  font-size: 12px;
  line-height: 1.7;
  color: var(--mist);
}

.footer-base {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 12px 24px;
  padding-block: 18px 30px;
  border-top: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.04em;
  color: var(--mist);
}

.footer-base__copy,
.footer-base__icp { margin: 0; }

.footer-base__links {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
}

.footer-base__links a {
  color: var(--mist);
  border-bottom: 1px solid transparent;
}

.footer-base__links a:hover {
  color: var(--lime);
  border-color: var(--lime);
}

/* ---------- 20. 响应式 ---------- */
@media (max-width: 1024px) {
  .footer-main { grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); }
  .footer-brand { grid-column: 1 / -1; }
  .footer-brand__summary { max-width: 46ch; }
}

@media (max-width: 900px) {
  .header-top { display: none; }

  .header-main__inner {
    min-height: 60px;
    gap: 16px;
  }

  .nav-toggle {
    display: inline-flex;
    margin-left: auto;
  }

  .site-nav {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    display: none;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    margin: 0;
    padding: 16px var(--gutter) 22px;
    background:
      linear-gradient(180deg, rgba(11, 47, 74, 0.99), rgba(6, 27, 46, 0.99));
    border-bottom: 1px solid var(--line);
    box-shadow: 0 34px 64px -34px rgba(0, 0, 0, 0.92);
    max-height: calc(100vh - 60px);
    overflow-y: auto;
  }

  .site-nav[data-open="true"] { display: flex; }

  .site-nav__list {
    flex-direction: column;
    align-items: stretch;
    gap: 2px;
  }

  .site-nav__list a {
    padding: 13px 10px;
    font-size: 17px;
    font-weight: 600;
    border-bottom: 1px solid rgba(157, 185, 201, 0.14);
  }

  .site-nav__list a::after { display: none; }

  .site-nav__list a[aria-current="page"] {
    background: rgba(184, 255, 214, 0.16);
    color: var(--lime-soft);
    box-shadow: inset 3px 0 0 var(--lime);
  }

  .site-nav__utility {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-top: 16px;
    padding-top: 16px;
    border-top: 1px solid rgba(157, 185, 201, 0.16);
  }

  .site-nav__utility a {
    display: inline-block;
    padding: 6px 12px;
    font-size: 13px;
    color: var(--mist);
    border: 1px solid var(--line);
    border-radius: 999px;
  }

  .site-nav__utility a:hover {
    color: var(--lime);
    border-color: var(--lime);
  }

  .site-nav__cta {
    display: flex;
    width: 100%;
    margin-top: 16px;
    padding: 13px 18px;
    font-size: 15px;
  }

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

@media (max-width: 720px) {
  :root { --gutter: 20px; }

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

  .footer-base {
    justify-content: flex-start;
    gap: 10px 18px;
  }

  .back-top {
    right: 14px;
    bottom: 14px;
    padding: 9px 14px;
  }
}

@media (max-width: 480px) {
  .site-nav__list a { font-size: 16px; }
  .footer-brand__summary { font-size: 13px; }
}

/* ---------- 21. 降低动效 ---------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }

  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
    scroll-behavior: auto !important;
  }
}