/* =========================================================
   红黑娱乐 · 共享样式表  /assets/site.css
   结构：reset → 变量 → 排版 → 容器 → 按钮 → 基础组件
        → 页头 → 页脚 → 阅读进度 → 动效降级 → 响应式
   ========================================================= */

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

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

body,
h1, h2, h3, h4, h5, h6,
p, figure, blockquote, dl, dd, ol, ul {
  margin: 0;
}

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

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

a {
  color: inherit;
}

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

/* ---------- 2. 变量 ---------- */
:root {
  /* 品牌色 */
  --red: #E8123C;
  --red-deep: #A80C2B;
  --black: #0A0A0F;
  --panel: #16161D;
  --cyan: #17E0D4;
  --gold: #F0B44A;

  /* 文字 */
  --text: #E6E6EA;
  --muted: #9A9AA6;

  /* 反色 */
  --paper: #F7F5F2;
  --ink: #1A1A22;

  /* 结构 */
  --grid: #2A2A34;
  --glow: rgba(232, 18, 60, 0.35);

  /* 半径：锐利直角为主 */
  --r-xs: 2px;
  --r-sm: 4px;
  --r-pill: 999px;

  /* 字号阶梯 12 / 14 / 16 / 20 / 28 / 40 / 56 / 72 */
  --fs-12: 12px;
  --fs-14: 14px;
  --fs-16: 16.5px;
  --fs-20: 20px;
  --fs-28: 28px;
  --fs-40: 40px;
  --fs-56: 56px;
  --fs-72: 72px;

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

  /* 布局 */
  --shell: 1240px;
  --gutter: clamp(16px, 3vw, 32px);
  --header-pad: 14px;

  /* 动效 */
  --ease: cubic-bezier(0.22, 0.61, 0.36, 1);
  --dur: 220ms;
}

/* ---------- 3. 基础排版 ---------- */
body {
  font-family: var(--font-body);
  font-size: var(--fs-16);
  line-height: 1.8;
  color: var(--text);
  background-color: var(--black);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-display);
  font-weight: 800;
  line-height: 1.16;
  letter-spacing: -0.02em;
  color: #fff;
  margin-bottom: 0.6em;
}

h1 { font-size: clamp(34px, 5.4vw, 72px); }
h2 { font-size: clamp(26px, 3.4vw, 40px); }
h3 { font-size: clamp(20px, 2vw, 28px); }
h4 { font-size: var(--fs-20); }
h5 { font-size: var(--fs-16); letter-spacing: 0; }
h6 { font-size: var(--fs-14); letter-spacing: 0; }

p {
  max-width: 68ch;
  margin-bottom: 1.2em;
}

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

a { text-decoration-thickness: 1px; text-underline-offset: 3px; }

strong, b { font-weight: 700; color: #fff; }

code, kbd, samp, pre {
  font-family: var(--font-mono);
  font-size: var(--fs-14);
  letter-spacing: 0.04em;
}

hr {
  border: 0;
  height: 1px;
  background: var(--grid);
  margin: 0;
}

::selection {
  background: var(--red);
  color: #fff;
}

:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 3px;
  border-radius: var(--r-xs);
}

.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;
}

/* ---------- 4. 容器与网格 ---------- */
.shell {
  width: 100%;
  max-width: var(--shell);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.section {
  padding-block: clamp(56px, 8vw, 112px);
}

.section--tight {
  padding-block: clamp(32px, 4.5vw, 60px);
}

.band {
  height: 6px;
  width: 100%;
  background: linear-gradient(90deg, var(--red), var(--red-deep) 40%, var(--grid) 75%, var(--cyan));
}

.rule {
  height: 1px;
  width: 100%;
  background: var(--grid);
}

.grid {
  display: grid;
  gap: clamp(16px, 2.2vw, 28px);
}

.grid--12 { grid-template-columns: repeat(12, minmax(0, 1fr)); }
.grid--6  { grid-template-columns: repeat(6, minmax(0, 1fr)); }
.grid--3  { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.grid--2  { grid-template-columns: repeat(2, minmax(0, 1fr)); }

.span-3  { grid-column: span 3; }
.span-4  { grid-column: span 4; }
.span-5  { grid-column: span 5; }
.span-6  { grid-column: span 6; }
.span-7  { grid-column: span 7; }
.span-8  { grid-column: span 8; }
.span-12 { grid-column: span 12; }

.stack > * + * { margin-top: 1.2em; }

/* 等宽索引元素：只出现在编号与时间戳位置 */
.mono {
  font-family: var(--font-mono);
  font-size: var(--fs-14);
  letter-spacing: 0.04em;
  color: var(--muted);
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--muted);
}

.eyebrow::before {
  content: "";
  width: 24px;
  height: 1px;
  background: var(--red);
}

.lead {
  font-size: clamp(17px, 1.6vw, 20px);
  line-height: 1.75;
  color: var(--text);
  max-width: 46ch;
}

/* ---------- 5. 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 12px 22px;
  border: 1px solid transparent;
  border-radius: var(--r-xs);
  font-family: var(--font-display);
  font-size: var(--fs-14);
  font-weight: 700;
  letter-spacing: 0.02em;
  text-decoration: none;
  cursor: pointer;
  transition: background-color var(--dur) var(--ease),
    border-color var(--dur) var(--ease),
    color var(--dur) var(--ease);
}

.btn--primary {
  background: var(--red);
  border-color: var(--red);
  color: #fff;
}

.btn--primary:hover {
  background: var(--red-deep);
  border-color: var(--cyan);
}

.btn--ghost {
  background: transparent;
  border-color: var(--grid);
  color: var(--text);
}

.btn--ghost:hover {
  border-color: var(--cyan);
  color: var(--cyan);
}

.btn--light {
  background: var(--paper);
  border-color: var(--paper);
  color: var(--ink);
}

.btn--light:hover {
  background: #fff;
  border-color: var(--red);
}

.btn--sm {
  padding: 8px 14px;
  font-size: var(--fs-12);
}

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

/* ---------- 6. 面包屑 ---------- */
.breadcrumb {
  padding-block: 20px 0;
}

.breadcrumb ol {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.06em;
  color: var(--muted);
}

.breadcrumb li {
  display: inline-flex;
  align-items: center;
}

.breadcrumb li + li::before {
  content: "/";
  margin: 0 10px;
  color: var(--grid);
}

.breadcrumb a {
  color: var(--muted);
  text-decoration: none;
  transition: color var(--dur) var(--ease);
}

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

.breadcrumb [aria-current="page"] { color: var(--text); }

/* ---------- 7. 卡片 / 索引行 / 快照 ---------- */
.card {
  position: relative;
  padding: clamp(20px, 2.4vw, 28px);
  background: var(--panel);
  border: 1px solid var(--grid);
  border-radius: var(--r-sm);
  transition: border-color var(--dur) var(--ease);
}

.card::before {
  content: "";
  position: absolute;
  top: -1px;
  left: -1px;
  width: 0;
  height: 1px;
  background: var(--red);
  transition: width 240ms var(--ease);
}

.card:hover { border-color: var(--cyan); }
.card:hover::before { width: 24px; }

.card__title {
  font-size: var(--fs-20);
  margin-bottom: 0.4em;
}

.card__meta {
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.06em;
  color: var(--muted);
}

.index-row {
  display: grid;
  grid-template-columns: 64px 1fr auto;
  gap: 16px;
  align-items: baseline;
  padding: 14px 0;
  border-bottom: 1px solid var(--grid);
}

.index-num {
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.08em;
  color: var(--muted);
  transition: color var(--dur) var(--ease);
}

.index-row:hover .index-num,
.index-row.is-active .index-num { color: var(--red); }

.index-meta {
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.04em;
  color: var(--muted);
}

.snapshot {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 12px;
  border: 1px solid rgba(240, 180, 74, 0.4);
  border-radius: var(--r-xs);
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.06em;
  color: var(--gold);
}

.snapshot::before {
  content: "";
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--gold);
  flex: 0 0 auto;
}

/* 章节锚点编号：进入视口时由中灰转正红 */
[data-section] .section-num,
.section-num {
  font-family: var(--font-mono);
  font-size: var(--fs-14);
  letter-spacing: 0.08em;
  color: var(--muted);
  transition: color var(--dur) var(--ease);
}

[data-section].is-active .section-num { color: var(--red); }

/* ---------- 8. 图片容器基础规则 ---------- */
.figure {
  position: relative;
  display: block;
  width: 100%;
  overflow: hidden;
  background: var(--panel);
  border: 1px solid var(--grid);
  border-radius: var(--r-xs);
}

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

.figure--16x9 { aspect-ratio: 16 / 9; }
.figure--4x3  { aspect-ratio: 4 / 3; }
.figure--1x1  { aspect-ratio: 1 / 1; }
.figure--21x9 { aspect-ratio: 21 / 9; }

.figure--glow::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background:
    radial-gradient(120% 90% at 22% 28%, var(--glow), transparent 62%),
    linear-gradient(180deg, rgba(10, 10, 15, 0) 40%, rgba(10, 10, 15, 0.72));
}

.figure--scan::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background: repeating-linear-gradient(
    180deg,
    rgba(255, 255, 255, 0.035) 0 1px,
    transparent 1px 4px
  );
}

.figure__caption {
  margin-top: 10px;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.05em;
  color: var(--muted);
}

/* ---------- 9. 反向（纸白）区块 ---------- */
.invert {
  background: var(--paper);
  color: var(--ink);
}

.invert h1, .invert h2, .invert h3, .invert h4 { color: var(--ink); }
.invert .lead { color: #3A3A46; }
.invert .mono, .invert .eyebrow, .invert .card__meta { color: #6A6A78; }
.invert .card { background: #fff; border-color: #DCD8D2; }
.invert .rule { background: #DCD8D2; }

/* ---------- 10. 跳转链接 ---------- */
.skip-link {
  position: absolute;
  top: -80px;
  left: var(--gutter);
  z-index: 130;
  padding: 10px 18px;
  background: var(--paper);
  color: var(--ink);
  border-radius: var(--r-xs);
  font-size: var(--fs-14);
  font-weight: 700;
  text-decoration: none;
  transition: top 200ms var(--ease);
}

.skip-link:focus {
  top: 16px;
}

/* ---------- 11. 页头：悬浮胶囊导航 ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 70;
  padding: var(--header-pad) var(--gutter);
  background: linear-gradient(
    180deg,
    rgba(10, 10, 15, 0.96) 0%,
    rgba(10, 10, 15, 0.82) 62%,
    rgba(10, 10, 15, 0) 100%
  );
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  transition: padding 240ms var(--ease);
}

.site-header[data-condensed] {
  padding-block: 8px;
}

.header-inner {
  position: relative;
  display: flex;
  align-items: center;
  gap: clamp(10px, 1.6vw, 20px);
  width: 100%;
  max-width: var(--shell);
  margin-inline: auto;
}

/* 品牌 */
.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  flex: 0 0 auto;
  padding: 7px 16px 7px 12px;
  border: 1px solid var(--grid);
  border-radius: var(--r-pill);
  background: rgba(22, 22, 29, 0.78);
  text-decoration: none;
  color: var(--text);
  transition: border-color var(--dur) var(--ease);
}

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

.brand-glyph {
  position: relative;
  flex: 0 0 auto;
  width: 22px;
  height: 22px;
  background: var(--red);
}

.brand-glyph::after {
  content: "";
  position: absolute;
  right: 3px;
  bottom: 3px;
  width: 8px;
  height: 3px;
  background: var(--cyan);
}

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

.brand-text strong {
  font-family: var(--font-display);
  font-size: 15px;
  font-weight: 800;
  letter-spacing: 0.01em;
  color: #fff;
}

.brand-text em {
  font-style: normal;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--muted);
}

/* 导航区 */
.site-nav {
  position: relative;
  flex: 1 1 auto;
  display: flex;
  justify-content: center;
  min-width: 0;
}

.nav-list {
  display: flex;
  align-items: center;
  gap: 2px;
  padding: 4px;
  border: 1px solid var(--grid);
  border-radius: var(--r-pill);
  background: rgba(22, 22, 29, 0.78);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
}

.nav-list li { display: flex; }

.nav-list a {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  padding: 8px 14px;
  border: 1px solid transparent;
  border-radius: var(--r-pill);
  font-size: var(--fs-14);
  text-decoration: none;
  color: var(--text);
  white-space: nowrap;
  transition: background-color var(--dur) var(--ease),
    color var(--dur) var(--ease),
    border-color var(--dur) var(--ease);
}

.nav-list a:hover {
  background: rgba(232, 18, 60, 0.16);
  color: #fff;
}

.nav-list a[aria-current="page"] {
  background: var(--red);
  border-color: var(--cyan);
  color: #fff;
}

.nav-idx {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.06em;
  color: var(--muted);
  transition: color var(--dur) var(--ease);
}

.nav-list a:hover .nav-idx { color: var(--cyan); }
.nav-list a[aria-current="page"] .nav-idx { color: rgba(255, 255, 255, 0.85); }

.nav-item--cta { display: none; }

.nav-cta-mobile {
  justify-content: center;
  background: var(--red);
  border-color: var(--red);
  color: #fff !important;
  font-weight: 700;
}

/* 折叠按钮 */
.nav-toggle {
  display: none;
  align-items: center;
  gap: 10px;
  padding: 8px 14px;
  border: 1px solid var(--grid);
  border-radius: var(--r-pill);
  background: rgba(22, 22, 29, 0.86);
  color: var(--text);
  font-size: var(--fs-12);
  letter-spacing: 0.04em;
  cursor: pointer;
  transition: border-color var(--dur) var(--ease), color var(--dur) var(--ease);
}

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

.nav-toggle-mark {
  position: relative;
  flex: 0 0 auto;
  width: 16px;
  height: 10px;
}

.nav-toggle-mark::before,
.nav-toggle-mark::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  height: 1px;
  background: var(--cyan);
  transition: transform var(--dur) var(--ease);
}

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

.nav-toggle-text {
  font-family: var(--font-mono);
  white-space: nowrap;
}

/* 右侧主 CTA */
.header-cta {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  flex: 0 0 auto;
  padding: 10px 18px;
  border: 1px solid var(--red);
  border-radius: var(--r-pill);
  background: var(--red);
  color: #fff;
  font-family: var(--font-display);
  font-size: var(--fs-14);
  font-weight: 700;
  letter-spacing: 0.01em;
  text-decoration: none;
  white-space: nowrap;
  transition: background-color var(--dur) var(--ease),
    border-color var(--dur) var(--ease);
}

.header-cta::after {
  content: "";
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--cyan);
  flex: 0 0 auto;
}

.header-cta:hover {
  background: var(--red-deep);
  border-color: var(--cyan);
}

/* ---------- 12. 页脚 ---------- */
.site-footer {
  position: relative;
  background: var(--black);
  color: var(--text);
}

.footer-rule {
  height: 1px;
  width: 100%;
  background: linear-gradient(
    90deg,
    var(--red) 0%,
    var(--red-deep) 30%,
    var(--grid) 68%,
    var(--cyan) 100%
  );
}

.footer-inner {
  max-width: var(--shell);
  margin-inline: auto;
  padding: clamp(40px, 6vw, 76px) var(--gutter) 0;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.35fr 1fr 1.5fr 1fr;
  gap: clamp(24px, 3vw, 48px);
}

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

.footer-brand {
  font-family: var(--font-display);
  font-size: var(--fs-20);
  font-weight: 800;
  letter-spacing: -0.01em;
  color: #fff;
  margin-bottom: 2px;
  max-width: none;
}

.footer-claim {
  display: inline-block;
  padding: 3px 10px;
  border: 1px solid rgba(232, 18, 60, 0.5);
  border-radius: var(--r-xs);
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.08em;
  color: var(--red);
  margin-bottom: 14px;
  max-width: none;
}

.footer-desc {
  font-size: var(--fs-14);
  line-height: 1.85;
  color: var(--muted);
  max-width: 30ch;
  margin-bottom: 0;
}

.footer-title {
  font-family: var(--font-display);
  font-size: var(--fs-12);
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 16px;
}

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

.footer-links a {
  font-size: var(--fs-14);
  text-decoration: none;
  color: var(--text);
  transition: color var(--dur) var(--ease);
}

.footer-links a:hover { color: var(--cyan); }

.footer-links--legal a { color: var(--muted); }
.footer-links--legal a:hover { color: var(--red); }

.footer-contact li + li { margin-top: 12px; }

.footer-contact li {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.footer-key {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--gold);
}

.footer-value {
  font-size: var(--fs-14);
  line-height: 1.7;
  color: var(--text);
  word-break: break-word;
}

.footer-note {
  margin-top: 16px;
  padding-top: 14px;
  border-top: 1px solid var(--grid);
  font-size: var(--fs-12);
  line-height: 1.75;
  color: var(--muted);
  max-width: 40ch;
  margin-bottom: 0;
}

.footer-base {
  margin-top: clamp(32px, 5vw, 60px);
  background: var(--paper);
  color: var(--ink);
}

.footer-base-inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 8px 28px;
  max-width: var(--shell);
  margin-inline: auto;
  padding: 16px var(--gutter);
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.05em;
}

.footer-base-inner p {
  margin-bottom: 0;
  max-width: none;
}

.footer-icp { color: var(--ink); }
.footer-copy { color: #6A6A78; }
.footer-host { color: #6A6A78; }

/* ---------- 13. 阅读进度 ---------- */
.read-progress {
  position: fixed;
  top: 0;
  left: 0;
  z-index: 90;
  width: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--red), var(--cyan));
  pointer-events: none;
  transition: width 90ms linear;
}

/* ---------- 14. 显现动效 ---------- */
[data-reveal] {
  opacity: 0;
  transform: translateY(14px);
  transition: opacity 260ms var(--ease), transform 260ms var(--ease);
}

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

/* ---------- 15. 响应式 ---------- */
@media (max-width: 1080px) {
  .footer-grid { grid-template-columns: 1.3fr 1fr 1.3fr; }
  .footer-col--legal { grid-column: 1 / -1; }
  .footer-links--legal { display: flex; gap: 24px; }
  .footer-links--legal li + li { margin-top: 0; }
}

@media (max-width: 900px) {
  .site-header { padding-block: 10px; }

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

  .site-nav { flex: 0 1 auto; margin-left: auto; }

  .brand-text em { display: none; }

  .nav-list {
    position: absolute;
    top: calc(100% + 10px);
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: stretch;
    gap: 4px;
    padding: 10px;
    border-radius: 14px;
    background: rgba(14, 14, 20, 0.98);
    box-shadow: 0 24px 56px rgba(0, 0, 0, 0.55);
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
    transform: translateY(-8px);
    transition: opacity 200ms var(--ease), transform 200ms var(--ease),
      visibility 200ms var(--ease);
  }

  .site-nav[data-open] .nav-list {
    opacity: 1;
    visibility: visible;
    pointer-events: auto;
    transform: translateY(0);
  }

  .nav-list li { display: block; }

  .nav-list a {
    justify-content: flex-start;
    width: 100%;
    padding: 11px 14px;
    border-radius: var(--r-sm);
    font-size: var(--fs-16);
  }

  .nav-item--cta { display: block; margin-top: 6px; }
  .nav-item--cta .nav-cta-mobile { display: inline-flex; }

  .grid--12, .grid--6, .grid--3 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .span-3, .span-4, .span-5, .span-6, .span-7, .span-8 { grid-column: span 2; }
  .span-12 { grid-column: 1 / -1; }

  .footer-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .footer-col--brand,
  .footer-col--contact { grid-column: 1 / -1; }
  .footer-desc { max-width: 46ch; }
}

@media (max-width: 640px) {
  :root { --fs-16: 16px; }

  .brand { padding: 7px 10px; }
  .brand-text { display: none; }
  .header-cta { display: none; }

  .nav-toggle { margin-left: auto; }

  .header-inner { justify-content: space-between; }

  .grid--2 { grid-template-columns: minmax(0, 1fr); }
  .grid--12, .grid--6, .grid--3 { grid-template-columns: minmax(0, 1fr); }
  .span-3, .span-4, .span-5, .span-6, .span-7, .span-8, .span-12 { grid-column: 1 / -1; }

  .footer-grid { grid-template-columns: minmax(0, 1fr); }
  .footer-links--legal { flex-direction: column; gap: 10px; }

  .footer-base-inner { flex-direction: column; align-items: flex-start; }

  .index-row { grid-template-columns: 52px 1fr; }
  .index-row .index-meta { grid-column: 2; }
}

/* ---------- 16. 桌面折叠态浮岛 ---------- */
@media (min-width: 901px) {
  .site-header[data-condensed] { padding-block: 8px; }

  .site-header[data-condensed] .brand-text { display: none; }
  .site-header[data-condensed] .brand { padding: 7px 9px; }
  .site-header[data-condensed] .nav-toggle { display: inline-flex; }

  .site-header[data-condensed] .nav-list {
    position: absolute;
    top: calc(100% + 10px);
    left: auto;
    right: 0;
    width: min(300px, 90vw);
    flex-direction: column;
    align-items: stretch;
    gap: 4px;
    padding: 10px;
    border-radius: 14px;
    background: rgba(14, 14, 20, 0.98);
    box-shadow: 0 24px 56px rgba(0, 0, 0, 0.55);
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
    transform: translateY(-8px);
    transition: opacity 200ms var(--ease), transform 200ms var(--ease),
      visibility 200ms var(--ease);
  }

  .site-header[data-condensed] .site-nav[data-open] .nav-list {
    opacity: 1;
    visibility: visible;
    pointer-events: auto;
    transform: translateY(0);
  }

  .site-header[data-condensed] .nav-list li { display: block; }

  .site-header[data-condensed] .nav-list a {
    justify-content: flex-start;
    width: 100%;
    padding: 10px 14px;
    border-radius: var(--r-sm);
    font-size: var(--fs-14);
  }

  .site-header[data-condensed] .nav-item--cta { display: block; margin-top: 6px; }
  .site-header[data-condensed] .nav-item--cta .nav-cta-mobile { display: inline-flex; }
}

/* ---------- 17. 动效降级 ---------- */
@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;
  }

  .read-progress { transition: none; }
}