/* ==========================================================================
   /assets/site.css — 大发体育方 · 共享外壳
   深冰海蓝图网格 / 2px 粗边 / 硬投影 / 荧光绿读数点
   ========================================================================== */

/* ---------- 1. Tokens ---------- */
:root {
  --ice-abyss: #06121F;
  --ice-deep: #0B2237;
  --ice-mid: #123A57;
  --ice-bright: #1E5A7D;
  --ice-light: #7FD4F0;
  --ice-white: #E8F4FA;
  --neon: #B6FF3C;
  --orange: #FF5A2B;
  --steel: #8DA6B8;
  --ice-pale: #C9DEE9;

  --bg: var(--ice-abyss);
  --bg-alt: var(--ice-deep);
  --fg: var(--ice-white);
  --fg-mute: var(--steel);
  --line: rgba(127, 212, 240, 0.20);
  --line-strong: rgba(127, 212, 240, 0.44);

  --ff-display: "PingFang SC", "Hiragino Sans GB", "Source Han Sans SC", "Noto Sans SC", "Microsoft YaHei", -apple-system, "Segoe UI", sans-serif;
  --ff-body: "PingFang SC", "Hiragino Sans GB", "Source Han Sans SC", "Noto Sans SC", "Microsoft YaHei", -apple-system, "Segoe UI", sans-serif;
  --ff-mono: ui-monospace, "SFMono-Regular", "SF Mono", "Cascadia Mono", "Roboto Mono", Menlo, Consolas, monospace;

  --fs-h1: clamp(2.2rem, 5vw, 4.2rem);
  --fs-h2: clamp(1.6rem, 3.2vw, 2.5rem);
  --fs-h3: clamp(1.15rem, 1.9vw, 1.5rem);
  --fs-body: clamp(16px, 0.35vw + 15px, 17px);

  --gutter: clamp(16px, 4vw, 40px);
  --maxw: 1280px;
  --maxw-narrow: 840px;
  --maxw-wide: 1480px;

  --header-h: 76px;
  --header-h-compact: 62px;

  --radius: 2px;
  --shadow-hard: 6px 6px 0 rgba(6, 18, 31, 0.82);
  --shadow-neon: 6px 6px 0 rgba(182, 255, 60, 0.16);
  --dur: 150ms;
}

/* ---------- 2. Reset ---------- */
*,
*::before,
*::after { box-sizing: border-box; }

html {
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-h) + 20px);
}

body {
  margin: 0;
  padding-top: var(--header-h);
  background-color: var(--bg);
  background-image:
    linear-gradient(rgba(127, 212, 240, 0.042) 1px, transparent 1px),
    linear-gradient(90deg, rgba(127, 212, 240, 0.042) 1px, transparent 1px);
  background-size: 72px 72px;
  background-attachment: fixed;
  color: var(--fg);
  font-family: var(--ff-body);
  font-size: var(--fs-body);
  line-height: 1.75;
  letter-spacing: 0.01em;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
}

img, svg, video, canvas { display: block; max-width: 100%; height: auto; }
button, input, select, textarea { font: inherit; color: inherit; }
ul, ol { margin: 0; }
[hidden] { display: none !important; }

/* ---------- 3. 中文排版 ---------- */
h1, h2, h3, h4, h5, h6 {
  margin: 0 0 0.5em;
  font-family: var(--ff-display);
  font-weight: 900;
  line-height: 1.1;
  letter-spacing: -0.02em;
  color: var(--ice-white);
  text-wrap: balance;
}
h1 { font-size: var(--fs-h1); line-height: 1.04; letter-spacing: -0.028em; }
h2 { font-size: var(--fs-h2); }
h3 { font-size: var(--fs-h3); line-height: 1.25; }
h4 { font-size: 1.05rem; line-height: 1.35; }

p { margin: 0 0 1.2em; }
p:last-child { margin-bottom: 0; }

a { color: var(--ice-light); text-decoration: none; }
a:hover { color: var(--neon); }
strong, b { font-weight: 800; color: var(--ice-white); }
small { font-size: 0.82em; }
hr { border: 0; height: 1px; background-color: var(--line); margin: 2em 0; }

::selection { background-color: var(--neon); color: var(--ice-abyss); }

/* ---------- 4. 焦点可见 ---------- */
a:focus-visible,
button:focus-visible,
[tabindex]:focus-visible,
summary:focus-visible,
input:focus-visible,
select:focus-visible,
textarea:focus-visible {
  outline: 2px solid var(--neon);
  outline-offset: 3px;
  border-radius: var(--radius);
}

.skip-link {
  position: fixed;
  left: 12px;
  top: -72px;
  z-index: 300;
  padding: 10px 18px;
  background-color: var(--neon);
  color: var(--ice-abyss);
  font-weight: 800;
  font-size: 14px;
  border-radius: var(--radius);
  box-shadow: 4px 4px 0 rgba(6, 18, 31, 0.9);
  transition: top var(--dur) linear;
}
.skip-link:focus,
.skip-link:focus-visible {
  top: 12px;
  color: var(--ice-abyss);
  outline: 2px solid var(--ice-abyss);
  outline-offset: 2px;
}

/* ---------- 5. 布局容器与分区 ---------- */
.container {
  width: 100%;
  max-width: var(--maxw);
  margin-inline: auto;
  padding-inline: var(--gutter);
}
.container--narrow { max-width: var(--maxw-narrow); }
.container--wide { max-width: var(--maxw-wide); }

.section {
  position: relative;
  padding-block: clamp(44px, 7vw, 96px);
}
.section--alt {
  background-color: var(--ice-deep);
  border-block: 1px solid var(--line);
}
.section--band {
  background-color: var(--ice-mid);
  border-block: 1px solid var(--line-strong);
}

.hero--overlay {
  margin-top: calc(var(--header-h) * -1);
  padding-top: var(--header-h);
}

/* ---------- 6. 蓝图索引与分隔线 ---------- */
.label-mono {
  display: inline-block;
  font-family: var(--ff-mono);
  font-size: 10.5px;
  font-weight: 700;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  line-height: 1.6;
  color: var(--ice-light);
}

.section-index {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--ff-mono);
  font-size: 11.5px;
  font-weight: 700;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  line-height: 1.6;
  color: var(--neon);
}
.section-index::before {
  content: "";
  flex: 0 0 auto;
  width: 26px;
  height: 2px;
  background-color: var(--neon);
}

.rule {
  display: block;
  width: 100%;
  height: 2px;
  margin: 0;
  border: 0;
  background-color: var(--ice-bright);
}
.hairline {
  display: block;
  width: 100%;
  height: 1px;
  margin: 0;
  border: 0;
  background-color: var(--line);
}

/* ---------- 7. 数字 ---------- */
.num {
  font-family: var(--ff-mono);
  font-variant-numeric: tabular-nums lining-nums;
  font-feature-settings: "tnum" 1, "lnum" 1;
  letter-spacing: 0.01em;
}

/* ---------- 8. 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 10px 18px;
  font-family: var(--ff-body);
  font-size: 14px;
  font-weight: 800;
  line-height: 1.2;
  letter-spacing: 0.01em;
  text-decoration: none;
  border: 2px solid transparent;
  border-radius: var(--radius);
  cursor: pointer;
  transition: transform var(--dur) linear, background-color var(--dur) linear,
              color var(--dur) linear, box-shadow var(--dur) linear,
              border-color var(--dur) linear;
}
.btn--primary {
  background-color: var(--neon);
  color: var(--ice-abyss);
  border-color: var(--neon);
  box-shadow: 4px 4px 0 rgba(182, 255, 60, 0.20);
}
.btn--primary:hover {
  color: var(--ice-abyss);
  transform: translate(-2px, -2px);
  box-shadow: 6px 6px 0 rgba(182, 255, 60, 0.30);
}
.btn--ghost {
  background-color: transparent;
  color: var(--ice-white);
  border-color: var(--ice-bright);
}
.btn--ghost:hover {
  color: var(--neon);
  border-color: var(--ice-light);
  background-color: rgba(30, 90, 125, 0.35);
}
.btn--sm { padding: 7px 13px; font-size: 12.5px; }
.btn--lg { padding: 14px 26px; font-size: 16px; }

.link-quiet {
  font-size: 12.5px;
  font-weight: 700;
  color: var(--ice-light);
  text-decoration: none;
  white-space: nowrap;
  border-bottom: 1px solid transparent;
  transition: color var(--dur) linear, border-color var(--dur) linear;
}
.link-quiet:hover {
  color: var(--neon);
  border-bottom-color: var(--neon);
}

/* ---------- 9. 页头 ---------- */
.site-header {
  position: fixed;
  inset: 0 0 auto 0;
  z-index: 100;
  color: var(--ice-white);
  background-color: transparent;
  border-bottom: 1px solid transparent;
  transition: background-color 180ms linear, border-color 180ms linear,
              box-shadow 180ms linear;
}
.site-header::after {
  content: "";
  position: absolute;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  background-image: linear-gradient(to bottom, rgba(6, 18, 31, 0.88), rgba(6, 18, 31, 0));
  opacity: 1;
  transition: opacity 180ms linear;
}
.site-header[data-scrolled="true"] {
  background-color: rgba(11, 34, 55, 0.97);
  border-bottom-color: var(--line-strong);
  box-shadow: 0 14px 34px rgba(6, 18, 31, 0.55);
}
.site-header[data-scrolled="true"]::after { opacity: 0; }

@supports ((-webkit-backdrop-filter: blur(8px)) or (backdrop-filter: blur(8px))) {
  .site-header[data-scrolled="true"] {
    background-color: rgba(11, 34, 55, 0.86);
    -webkit-backdrop-filter: blur(8px);
    backdrop-filter: blur(8px);
  }
}

.scroll-progress {
  position: absolute;
  left: 0;
  top: 0;
  width: 100%;
  height: 3px;
  z-index: 2;
  transform: scaleX(0);
  transform-origin: 0 50%;
  background-image: linear-gradient(90deg, var(--neon), var(--ice-light));
  pointer-events: none;
}

.header-inner {
  position: relative;
  width: 100%;
  max-width: var(--maxw);
  margin-inline: auto;
  padding-inline: var(--gutter);
  height: var(--header-h);
  display: flex;
  align-items: center;
  gap: clamp(10px, 1.6vw, 22px);
  transition: height 180ms linear;
}
.site-header[data-scrolled="true"] .header-inner { height: var(--header-h-compact); }

/* 品牌锁定 */
.brand-lockup {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  flex: 0 0 auto;
  padding: 4px 0;
  text-decoration: none;
  color: var(--ice-white);
  line-height: 1;
}
.brand-mark {
  width: 36px;
  height: 36px;
  flex: 0 0 auto;
  display: grid;
  place-items: center;
  font-family: var(--ff-mono);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.02em;
  line-height: 1;
  color: var(--neon);
  border: 2px solid var(--neon);
  border-radius: var(--radius);
  background-image: linear-gradient(135deg, rgba(182, 255, 60, 0.18), rgba(6, 18, 31, 0) 62%);
  box-shadow: 3px 3px 0 rgba(182, 255, 60, 0.22);
  transition: transform var(--dur) linear, box-shadow var(--dur) linear;
}
.brand-lockup:hover .brand-mark,
.footer-lockup:hover .brand-mark {
  transform: translate(-1px, -1px);
  box-shadow: 4px 4px 0 rgba(182, 255, 60, 0.32);
}
.brand-text {
  display: flex;
  flex-direction: column;
  gap: 3px;
  min-width: 0;
}
.brand-name {
  font-family: var(--ff-display);
  font-size: 16px;
  font-weight: 900;
  letter-spacing: -0.01em;
  color: var(--ice-white);
  white-space: nowrap;
}
.brand-sub {
  font-family: var(--ff-mono);
  font-size: 9.5px;
  font-weight: 600;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--ice-light);
  white-space: nowrap;
}
.version-badge {
  align-self: center;
  margin-left: 2px;
  padding: 2px 6px;
  font-family: var(--ff-mono);
  font-size: 10px;
  font-weight: 700;
  letter-spacing: 0.08em;
  line-height: 1.5;
  color: var(--ice-light);
  border: 1px solid var(--ice-bright);
  border-radius: var(--radius);
  background-color: rgba(30, 90, 125, 0.30);
  white-space: nowrap;
}

/* 主导航 */
.site-nav {
  display: flex;
  align-items: center;
  margin-left: auto;
  min-width: 0;
}
.nav-list {
  display: flex;
  align-items: center;
  flex-wrap: nowrap;
  gap: 2px;
  margin: 0;
  padding: 0;
  list-style: none;
}
.nav-link {
  position: relative;
  display: inline-block;
  padding: 9px 11px;
  font-size: 13.5px;
  font-weight: 600;
  line-height: 1.2;
  color: var(--ice-white);
  text-decoration: none;
  white-space: nowrap;
  border-radius: var(--radius);
  transition: color var(--dur) linear, background-color var(--dur) linear;
}
.nav-link::after {
  content: "";
  position: absolute;
  left: 11px;
  right: 11px;
  bottom: 2px;
  height: 2px;
  background-color: var(--neon);
  transform: scaleX(0);
  transform-origin: 0 50%;
  transition: transform var(--dur) linear;
}
.nav-link:hover {
  color: var(--neon);
  background-color: rgba(30, 90, 125, 0.30);
}
.nav-link:hover::after { transform: scaleX(1); }
.nav-link[aria-current="page"] { color: var(--neon); }
.nav-link[aria-current="page"]::after { transform: scaleX(1); }

.nav-foot { display: none; }

/* 右侧工具区 */
.header-actions {
  display: flex;
  align-items: center;
  gap: 10px;
  flex: 0 0 auto;
  margin-left: 12px;
}
.header-stamp {
  font-family: var(--ff-mono);
  font-size: 10.5px;
  letter-spacing: 0.1em;
  color: var(--steel);
  white-space: nowrap;
  opacity: 0;
  transition: opacity 180ms linear;
}
.site-header[data-scrolled="true"] .header-stamp { opacity: 1; }
.header-cta { box-shadow: 3px 3px 0 rgba(182, 255, 60, 0.18); }

/* 移动菜单按钮 */
.nav-toggle {
  display: none;
  align-items: center;
  gap: 8px;
  margin-left: auto;
  padding: 9px 12px;
  font-family: var(--ff-body);
  font-size: 13px;
  font-weight: 700;
  line-height: 1.2;
  color: var(--ice-white);
  background-color: rgba(30, 90, 125, 0.38);
  border: 2px solid var(--ice-bright);
  border-radius: var(--radius);
  cursor: pointer;
  transition: border-color var(--dur) linear, color var(--dur) linear,
              background-color var(--dur) linear;
}
.nav-toggle:hover {
  color: var(--neon);
  border-color: var(--ice-light);
}
.nav-toggle-bars {
  display: inline-flex;
  flex-direction: column;
  justify-content: space-between;
  width: 16px;
  height: 12px;
}
.nav-toggle-bars span {
  display: block;
  height: 2px;
  width: 100%;
  background-color: currentColor;
  transition: transform var(--dur) linear, opacity var(--dur) linear;
}
.nav-toggle[aria-expanded="true"] .nav-toggle-bars span:nth-child(1) {
  transform: translateY(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(-5px) rotate(-45deg);
}
.nav-toggle-label { white-space: nowrap; }

/* ---------- 10. 页脚 ---------- */
.site-footer {
  position: relative;
  margin-top: 0;
  padding-block: clamp(40px, 6vw, 72px) clamp(20px, 3vw, 30px);
  background-color: var(--ice-deep);
  border-top: 2px solid var(--ice-bright);
  color: var(--ice-white);
}
.site-footer::before {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  top: -2px;
  height: 6px;
  pointer-events: none;
  background-image: repeating-linear-gradient(
    135deg,
    var(--neon) 0 8px,
    rgba(182, 255, 60, 0) 8px 18px
  );
  opacity: 0.55;
}
.footer-inner {
  width: 100%;
  max-width: var(--maxw);
  margin-inline: auto;
  padding-inline: var(--gutter);
}
.footer-top {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 2fr);
  gap: clamp(26px, 5vw, 72px);
  padding-bottom: clamp(24px, 4vw, 40px);
  border-bottom: 1px solid var(--line);
}
.footer-lockup {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: var(--ice-white);
}
.footer-brand-name {
  font-family: var(--ff-display);
  font-size: clamp(18px, 2vw, 22px);
  font-weight: 900;
  letter-spacing: -0.01em;
  color: var(--ice-white);
}
.footer-brand-sub {
  margin: 14px 0 0;
  font-family: var(--ff-mono);
  font-size: 10.5px;
  font-weight: 600;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--ice-light);
}
.footer-note {
  margin: 10px 0 0;
  max-width: 32ch;
  font-size: 13.5px;
  line-height: 1.7;
  color: var(--steel);
}
.footer-groups {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: clamp(16px, 3vw, 32px);
}
.footer-group-title {
  margin: 0 0 14px;
  font-family: var(--ff-mono);
  font-size: 10.5px;
  font-weight: 700;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  line-height: 1.6;
  color: var(--ice-light);
}
.footer-links {
  display: grid;
  gap: 9px;
  margin: 0;
  padding: 0;
  list-style: none;
}
.footer-links a {
  display: inline-block;
  padding-bottom: 1px;
  font-size: 14.5px;
  color: var(--ice-white);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color var(--dur) linear, border-color var(--dur) linear;
}
.footer-links a:hover {
  color: var(--neon);
  border-bottom-color: var(--neon);
}
.footer-contact {
  display: grid;
  gap: 5px;
  margin-top: clamp(20px, 3vw, 28px);
  padding-top: clamp(18px, 2.6vw, 24px);
  border-top: 1px solid var(--line);
}
.contact-line {
  margin: 0;
  font-size: 14px;
  line-height: 1.7;
  color: var(--ice-pale);
}
.contact-note {
  margin: 6px 0 0;
  font-size: 12.5px;
  line-height: 1.7;
  color: var(--steel);
}
.footer-wordmark {
  margin: clamp(24px, 4vw, 40px) 0 0;
  font-family: var(--ff-display);
  font-size: clamp(2.6rem, 11vw, 7.5rem);
  font-weight: 900;
  line-height: 0.86;
  letter-spacing: -0.04em;
  color: rgba(127, 212, 240, 0.10);
  -webkit-text-stroke: 1px rgba(30, 90, 125, 0.9);
  user-select: none;
  pointer-events: none;
  overflow: hidden;
  white-space: nowrap;
}
.footer-meta {
  display: grid;
  gap: 8px;
  margin-top: clamp(18px, 3vw, 28px);
  padding-top: clamp(16px, 2.6vw, 22px);
  border-top: 1px solid var(--line);
}
.legal-line {
  margin: 0;
  font-family: var(--ff-mono);
  font-size: 11.5px;
  letter-spacing: 0.05em;
  line-height: 1.8;
  color: var(--steel);
}
.footer-closing {
  margin: 0;
  font-size: 13.5px;
  line-height: 1.7;
  color: var(--ice-pale);
}
.copyright-line {
  margin: 0;
  font-family: var(--ff-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  color: rgba(141, 166, 184, 0.72);
}

/* ---------- 11. 卡片 / 标签 / 网格 ---------- */
.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)); }

.grid-12 {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  gap: clamp(12px, 2vw, 24px);
}
.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-12 { grid-column: span 12; }

.card {
  position: relative;
  padding: clamp(16px, 2.4vw, 26px);
  background-color: var(--ice-deep);
  border: 2px solid var(--ice-bright);
  border-radius: var(--radius);
  box-shadow: var(--shadow-hard);
}
.card--flat {
  background-color: var(--ice-mid);
  box-shadow: none;
  border-color: var(--line-strong);
}
.card--neon {
  border-color: var(--neon);
  box-shadow: var(--shadow-neon);
}
.card__title {
  margin: 0 0 6px;
  font-size: clamp(1rem, 1.4vw, 1.15rem);
  font-weight: 800;
  line-height: 1.35;
  letter-spacing: -0.01em;
}
.card__meta {
  margin: 0;
  font-family: var(--ff-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--steel);
}

.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 3px 8px;
  font-family: var(--ff-mono);
  font-size: 10px;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  line-height: 1.6;
  color: var(--ice-light);
  background-color: rgba(30, 90, 125, 0.28);
  border: 1px solid var(--ice-bright);
  border-radius: var(--radius);
  white-space: nowrap;
}
.tag--live {
  color: var(--orange);
  border-color: var(--orange);
  background-color: rgba(255, 90, 43, 0.10);
  background-image: repeating-linear-gradient(
    45deg,
    rgba(255, 90, 43, 0.20) 0 3px,
    rgba(255, 90, 43, 0) 3px 7px
  );
}
.tag--neon {
  color: var(--neon);
  border-color: var(--neon);
  background-color: rgba(182, 255, 60, 0.08);
}
.tag--muted {
  color: var(--steel);
  border-color: var(--line-strong);
  background-color: transparent;
}

/* ---------- 12. 图片容器基础 ---------- */
.media-frame {
  position: relative;
  display: block;
  overflow: hidden;
  aspect-ratio: 16 / 9;
  border: 2px solid var(--ice-bright);
  border-radius: var(--radius);
  background-color: var(--ice-deep);
  background-image:
    linear-gradient(158deg, rgba(30, 90, 125, 0.72), rgba(6, 18, 31, 0.10) 62%),
    repeating-linear-gradient(
      90deg,
      rgba(127, 212, 240, 0.12) 0 1px,
      rgba(127, 212, 240, 0) 1px 56px
    ),
    repeating-linear-gradient(
      0deg,
      rgba(127, 212, 240, 0.06) 0 1px,
      rgba(127, 212, 240, 0) 1px 56px
    );
  background-size: cover, auto, auto;
}
.media-frame > img,
.media-frame > picture > img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}
.media-frame--wide { aspect-ratio: 21 / 9; }
.media-frame--square { aspect-ratio: 1 / 1; }
.media-frame--tall { aspect-ratio: 4 / 5; }
.media-frame__caption {
  position: absolute;
  left: 0;
  bottom: 0;
  right: 0;
  padding: 10px 12px;
  font-family: var(--ff-mono);
  font-size: 10.5px;
  letter-spacing: 0.1em;
  line-height: 1.6;
  color: var(--ice-white);
  background-image: linear-gradient(to top, rgba(6, 18, 31, 0.92), rgba(6, 18, 31, 0));
}

/* ---------- 13. 面包屑 ---------- */
.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 4px 6px;
  margin: 0;
  padding: 0;
  list-style: none;
  font-family: var(--ff-mono);
  font-size: 11.5px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--steel);
}
.breadcrumb li { display: inline-flex; align-items: center; gap: 6px; }
.breadcrumb li + li::before {
  content: "/";
  color: var(--ice-bright);
  margin-right: 6px;
}
.breadcrumb a {
  color: var(--steel);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color var(--dur) linear, border-color var(--dur) linear;
}
.breadcrumb a:hover {
  color: var(--neon);
  border-bottom-color: var(--neon);
}
.breadcrumb [aria-current="page"] { color: var(--ice-light); }

/* ---------- 14. 长文 ---------- */
.prose { max-width: 72ch; }
.prose > * + * { margin-top: 1.2em; }
.prose h2 { margin-top: 2.2em; margin-bottom: 0.6em; font-size: var(--fs-h2); }
.prose h3 { margin-top: 1.8em; margin-bottom: 0.5em; font-size: var(--fs-h3); }
.prose ul,
.prose ol { margin: 1.2em 0; padding-left: 1.3em; }
.prose li + li { margin-top: 0.45em; }
.prose a {
  color: var(--ice-light);
  text-decoration: underline;
  text-underline-offset: 3px;
  text-decoration-thickness: 1px;
}
.prose a:hover { color: var(--neon); }
.prose blockquote {
  margin: 1.6em 0;
  padding: 4px 0 4px 18px;
  border-left: 2px solid var(--neon);
  color: var(--ice-pale);
}

/* ---------- 15. 返回顶部 ---------- */
.back-to-top {
  position: fixed;
  right: clamp(12px, 3vw, 28px);
  bottom: clamp(12px, 3vw, 28px);
  z-index: 90;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 14px;
  font-family: var(--ff-mono);
  font-size: 11.5px;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  line-height: 1.2;
  color: var(--ice-abyss);
  background-color: var(--neon);
  border: 2px solid var(--neon);
  border-radius: var(--radius);
  box-shadow: 4px 4px 0 rgba(6, 18, 31, 0.85);
  cursor: pointer;
  opacity: 0;
  transform: translateY(14px);
  pointer-events: none;
  transition: opacity 180ms linear, transform 180ms linear, box-shadow var(--dur) linear;
}
.back-to-top[data-visible="true"] {
  opacity: 1;
  transform: translateY(0);
  pointer-events: auto;
}
.back-to-top:hover {
  color: var(--ice-abyss);
  box-shadow: 6px 6px 0 rgba(6, 18, 31, 0.95);
}

/* ---------- 16. 响应式 ---------- */
@media (max-width: 1180px) {
  .header-stamp { display: none; }
  .nav-link { padding: 9px 8px; font-size: 13px; }
  .nav-link::after { left: 8px; right: 8px; }
}

@media (max-width: 1024px) {
  .version-badge { display: none; }
  .header-actions .link-quiet { display: none; }
}

@media (max-width: 960px) {
  :root { --header-h: 68px; }

  .site-header[data-scrolled="true"] .header-inner { height: var(--header-h); }

  .nav-toggle { display: inline-flex; }
  .header-actions { display: none; }

  .site-nav {
    position: fixed;
    left: 0;
    right: 0;
    top: var(--header-h);
    z-index: 99;
    display: none;
    flex-direction: column;
    align-items: stretch;
    margin-left: 0;
    padding: 12px var(--gutter) 24px;
    background-color: var(--ice-deep);
    border-bottom: 2px solid var(--ice-bright);
    box-shadow: 0 24px 50px rgba(6, 18, 31, 0.62);
    max-height: calc(100vh - var(--header-h));
    max-height: calc(100dvh - var(--header-h));
    overflow-y: auto;
    overscroll-behavior: contain;
  }
  .site-nav[data-open="true"] { display: flex; }

  .nav-list {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
  }
  .nav-list li + li { border-top: 1px solid var(--line); }
  .nav-link {
    display: block;
    padding: 14px 4px;
    font-size: 15.5px;
    border-radius: 0;
  }
  .nav-link::after {
    left: 4px;
    right: auto;
    width: 22px;
    bottom: 9px;
  }

  .nav-foot {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-top: 18px;
    padding-top: 16px;
    border-top: 1px solid var(--line);
  }

  .footer-top { grid-template-columns: 1fr; }
}

@media (max-width: 900px) {
  .grid--3,
  .grid--4 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .col-4,
  .col-5,
  .col-6,
  .col-7,
  .col-8 { grid-column: span 12; }
}

@media (max-width: 720px) {
  body { background-size: 48px 48px; }
  .footer-groups { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 22px 18px; }
  .brand-sub { display: none; }
  .footer-wordmark { white-space: normal; line-height: 0.95; }
}

@media (max-width: 620px) {
  .grid--2,
  .grid--3,
  .grid--4 { grid-template-columns: 1fr; }
  .btn { padding: 10px 16px; }
  .btn--lg { padding: 13px 22px; font-size: 15px; }
}

@media (max-width: 480px) {
  .footer-groups { grid-template-columns: 1fr; gap: 20px; }
  .back-to-top { padding: 9px 11px; font-size: 10.5px; }
  .brand-lockup { gap: 8px; }
  .brand-mark { width: 32px; height: 32px; font-size: 12px; }
  .brand-name { font-size: 15px; }
}

/* ---------- 17. 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;
  }
  .back-to-top { transform: none; }
}