/* ==========================================================================
   必胜28 · 共享样式表 /assets/site.css
   堆叠面板式布局 / 左右分置导航 / 红·墨蓝·暖白·荧光青 四色节奏
   ========================================================================== */

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

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: 112px;
}

body {
  margin: 0;
  background: var(--warm);
  color: var(--ink);
  font-family: var(--font-sans);
  font-size: var(--fs-16);
  font-weight: 400;
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

h1, h2, h3, h4, h5, h6, p, ul, ol, figure, blockquote, dl, dd { margin: 0; }
ul, ol { list-style: none; padding: 0; }
img, svg, video { display: block; max-width: 100%; }
a { color: inherit; text-decoration: none; }
button, input, select, textarea { font: inherit; color: inherit; margin: 0; }
button { background: none; border: 0; cursor: pointer; }
table { border-collapse: collapse; width: 100%; }

/* ---------- 2. Design tokens ---------- */
:root {
  --red: #E2372B;
  --red-deep: #A61C12;
  --ink: #0D1B33;
  --ink-2: #1B2C4E;
  --warm: #FAF6EF;
  --paper: #FFFFFF;
  --cyan: #16E0CE;
  --cyan-deep: #0B8F86;
  --amber: #FFB020;
  --slate: #4A5568;
  --line: #DCD5C8;

  --fs-14: 0.875rem;
  --fs-16: 1rem;
  --fs-18: 1.125rem;
  --fs-22: 1.375rem;
  --fs-28: 1.75rem;
  --fs-40: 2.5rem;
  --fs-56: 3.5rem;
  --fs-72: 4.5rem;
  --fs-96: 6rem;

  --font-sans: "Noto Sans SC", "Source Han Sans SC", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  --font-mono: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, "Liberation Mono", monospace;

  --wrap: 1280px;
  --wrap-narrow: 720px;
  --gutter: clamp(20px, 4vw, 48px);
  --band: clamp(32px, 5vw, 84px);
  --header-h: 76px;
  --ease: cubic-bezier(.22, .61, .36, 1);
}

/* ---------- 3. 全局焦点与可访问性 ---------- */
:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 2px;
}

.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  z-index: 300;
  display: inline-block;
  padding: 12px 22px;
  background: var(--cyan);
  color: var(--ink);
  font-weight: 700;
  font-size: var(--fs-16);
  letter-spacing: .02em;
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 12px), calc(100% - 12px) 100%, 0 100%);
}
.skip-link:focus {
  left: 0;
}

/* ---------- 4. 中文排版基础 ---------- */
.mono,
.sec-index,
.card-eyebrow,
.board-label,
.path,
.stat-num,
.nav-path,
.contact-value--mono,
.footer-icp,
.eyebrow,
.tag {
  font-family: var(--font-mono);
}

.eyebrow {
  display: inline-block;
  font-size: var(--fs-14);
  font-weight: 700;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--red);
}

.muted { color: var(--slate); }
.strong { font-weight: 700; }

.note {
  font-size: var(--fs-14);
  line-height: 1.7;
  color: var(--slate);
}

.path {
  font-size: 1.06em;
  font-weight: 700;
  letter-spacing: -.01em;
  color: var(--ink);
  border-bottom: 3px solid var(--cyan);
  padding-bottom: 1px;
  white-space: nowrap;
}

.panel--ink .path,
.card--ink .path,
.site-footer .path {
  color: var(--warm);
}

/* ---------- 5. 布局容器与网格 ---------- */
.wrap {
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding-inline: var(--gutter);
}
.wrap--narrow { max-width: var(--wrap-narrow); }

.stack > * + * { margin-top: clamp(16px, 2.4vw, 32px); }

.grid {
  display: grid;
  gap: clamp(16px, 2vw, 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)); }

.shift-a { margin-inline-start: 0; }
.shift-b { margin-inline-start: clamp(0px, 3vw, 44px); }
.shift-c { margin-inline-start: clamp(0px, 6vw, 88px); }

/* ---------- 6. 章节面板 ---------- */
.panel {
  position: relative;
  background: var(--paper);
  border-top: 4px solid var(--ink);
  padding: clamp(24px, 4vw, 56px);
}
.panel--warm { background: var(--warm); }
.panel--ink {
  background: var(--ink);
  color: var(--warm);
  border-top-color: var(--red);
}
.panel--ink .sec-note,
.panel--ink .card-body,
.panel--ink .note { color: rgba(250, 246, 239, .72); }
.panel--ink .sec-title { color: var(--warm); }
.panel--red {
  background: var(--red);
  color: var(--paper);
  border-top-color: var(--red-deep);
}
.panel--red .sec-note { color: rgba(255, 255, 255, .82); }
.panel--cut {
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 34px), calc(100% - 34px) 100%, 0 100%);
}

.sec-head {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-start;
  gap: clamp(12px, 1.8vw, 22px);
}
.sec-index {
  flex: none;
  display: inline-block;
  padding: 5px 11px;
  background: var(--red);
  color: var(--paper);
  font-size: var(--fs-14);
  font-weight: 700;
  letter-spacing: .08em;
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 8px), calc(100% - 8px) 100%, 0 100%);
}
.panel--red .sec-index {
  background: var(--ink);
  color: var(--warm);
}
.sec-title {
  flex: 1 1 320px;
  font-size: clamp(1.75rem, 4vw, 3.5rem);
  font-weight: 900;
  line-height: 1.06;
  letter-spacing: -.02em;
}
.sec-note {
  flex: 1 1 260px;
  max-width: 56ch;
  font-size: var(--fs-16);
  line-height: 1.75;
  color: var(--slate);
}

.divider {
  height: 12px;
  border: 0;
  margin: 0;
  background:
    linear-gradient(112deg, transparent 0 46%, var(--red) 46% 58%, transparent 58% 100%),
    linear-gradient(112deg, transparent 0 68%, var(--cyan) 68% 74%, transparent 74% 100%);
}

/* ---------- 7. 卡片与专题研究板 ---------- */
.card {
  position: relative;
  background: var(--paper);
  border: 1px solid var(--line);
  padding: clamp(18px, 2.4vw, 32px);
}
.card--cut {
  border: 0;
  border-left: 4px solid var(--red);
  clip-path: polygon(0 0, calc(100% - 26px) 0, 100% 26px, 100% 100%, 0 100%);
}
.card--ink {
  background: var(--ink);
  border-color: var(--ink-2);
  color: var(--warm);
}
.card--ink .card-body { color: rgba(250, 246, 239, .72); }
.card--sweep { overflow: hidden; }
.card--sweep::before {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  top: 0;
  height: 4px;
  background: var(--red);
  transform: scaleX(0);
  transform-origin: left center;
  transition: transform .16s var(--ease);
}
.card--sweep:hover::before,
.card--sweep:focus-within::before { transform: scaleX(1); }

.card-eyebrow {
  display: block;
  font-size: var(--fs-14);
  font-weight: 700;
  letter-spacing: .12em;
  text-transform: uppercase;
  color: var(--red);
  margin-bottom: 10px;
}
.card--ink .card-eyebrow { color: var(--cyan); }
.card-title {
  font-size: var(--fs-22);
  font-weight: 900;
  line-height: 1.28;
  letter-spacing: -.01em;
  margin-bottom: 10px;
}
.card-body {
  font-size: var(--fs-16);
  line-height: 1.75;
  color: var(--slate);
}

.board {
  background: var(--paper);
  border-left: 6px solid var(--ink);
  padding: clamp(20px, 2.6vw, 36px);
}
.board--red { border-left-color: var(--red); }
.board-label {
  display: block;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--slate);
  margin-bottom: 10px;
}
.board-summary {
  font-size: var(--fs-18);
  font-weight: 600;
  line-height: 1.7;
  margin-bottom: clamp(16px, 2vw, 26px);
}
.board-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(190px, 1fr));
}
.board-cell {
  padding: 16px 18px;
  border-top: 1px solid var(--line);
  border-right: 1px solid var(--line);
}
.board-cell:last-child { border-right: 0; }

.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 10px;
  background: var(--ink);
  color: var(--warm);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: .06em;
  line-height: 1.5;
}
.tag--red { background: var(--red); color: var(--paper); }
.tag--amber { background: var(--amber); color: var(--ink); }
.tag--cyan { background: var(--cyan); color: var(--ink); }

.stat {
  display: flex;
  flex-direction: column;
  gap: 4px;
}
.stat-num {
  font-size: clamp(1.75rem, 4vw, 3.5rem);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -.02em;
  color: var(--red);
}
.stat-label {
  font-size: var(--fs-14);
  color: var(--slate);
}
.panel--ink .stat-label { color: rgba(250, 246, 239, .68); }

.list-check {
  display: grid;
  gap: 10px;
}
.list-check li {
  position: relative;
  padding-inline-start: 26px;
  line-height: 1.7;
}
.list-check li::before {
  content: "";
  position: absolute;
  left: 0;
  top: .72em;
  width: 12px;
  height: 3px;
  background: var(--red);
}
.panel--ink .list-check li::before { background: var(--cyan); }

/* ---------- 8. 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 11px 20px;
  border: 2px solid transparent;
  font-size: 15px;
  font-weight: 700;
  line-height: 1.25;
  letter-spacing: .01em;
  white-space: nowrap;
  transition: background-color .16s var(--ease), color .16s var(--ease), border-color .16s var(--ease);
}
.btn-primary {
  background: var(--red);
  color: var(--paper);
}
.btn-primary:hover,
.btn-primary:focus-visible {
  background: var(--red-deep);
  color: var(--paper);
}
.btn-ghost {
  background: transparent;
  color: var(--ink);
  border-color: var(--ink);
}
.btn-ghost:hover,
.btn-ghost:focus-visible {
  background: var(--ink);
  color: var(--warm);
}
.btn-quiet {
  padding: 6px 0;
  color: var(--ink);
  border: 0;
  border-bottom: 2px solid transparent;
}
.btn-quiet:hover,
.btn-quiet:focus-visible {
  color: var(--red);
  border-bottom-color: var(--cyan);
}

/* ---------- 9. 头部 ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 60;
  background: var(--warm);
  border-bottom: 2px solid var(--ink);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: clamp(16px, 2vw, 32px);
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding: 12px var(--gutter);
  min-height: var(--header-h);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  flex: none;
}
.brand-mark {
  display: grid;
  place-items: center;
  width: 44px;
  height: 44px;
  background: var(--red);
  color: var(--paper);
  font-family: var(--font-mono);
  font-size: 17px;
  font-weight: 700;
  letter-spacing: -.02em;
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 13px), calc(100% - 13px) 100%, 0 100%);
}
.brand-text { display: block; }
.brand-name {
  display: block;
  font-size: 20px;
  font-weight: 900;
  line-height: 1.15;
  letter-spacing: -.02em;
  color: var(--ink);
}
.brand-suffix {
  display: block;
  font-size: 12px;
  line-height: 1.4;
  letter-spacing: .1em;
  color: var(--slate);
}

.nav-toggle {
  display: none;
  align-items: center;
  gap: 10px;
  padding: 10px 14px;
  border: 2px solid var(--ink);
  background: var(--paper);
  color: var(--ink);
  font-size: 14px;
  font-weight: 700;
  z-index: 90;
}
.nav-toggle-icon {
  display: grid;
  gap: 4px;
  width: 18px;
}
.nav-toggle-icon span {
  display: block;
  height: 2px;
  background: currentColor;
  transition: transform .2s var(--ease), opacity .2s var(--ease);
}
.nav-toggle[aria-expanded="true"] .nav-toggle-icon span:nth-child(1) { transform: translateY(6px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle-icon span:nth-child(2) { opacity: 0; }
.nav-toggle[aria-expanded="true"] .nav-toggle-icon span:nth-child(3) { transform: translateY(-6px) rotate(-45deg); }

.site-nav {
  display: flex;
  align-items: center;
  gap: clamp(14px, 2vw, 32px);
}

.nav-list {
  display: flex;
  align-items: center;
  gap: clamp(10px, 1.5vw, 24px);
}
.nav-item { display: block; }
.nav-link {
  position: relative;
  display: block;
  padding: 8px 2px 10px;
  font-size: 15px;
  font-weight: 600;
  color: var(--ink);
  white-space: nowrap;
  transition: color .16s var(--ease);
}
.nav-link::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  height: 3px;
  width: 0;
  background: var(--red);
  transition: width .16s var(--ease);
}
.nav-link:hover { color: var(--red); }
.nav-link:hover::after,
.nav-link:focus-visible::after { width: 100%; }
.nav-link[aria-current="page"] { color: var(--red); }
.nav-link[aria-current="page"]::after { width: 100%; background: var(--red); }

.nav-path {
  display: none;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: .02em;
  opacity: .6;
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 10px;
  flex: none;
}

/* ---------- 10. 页脚 ---------- */
.site-footer {
  margin-top: clamp(40px, 6vw, 96px);
  background: var(--ink);
  color: var(--warm);
  border-top: 6px solid var(--red);
}

.footer-inner {
  display: grid;
  grid-template-columns: 1.5fr 1fr 1fr 1fr 1.4fr;
  gap: clamp(24px, 3vw, 48px);
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding: clamp(32px, 5vw, 72px) var(--gutter) clamp(24px, 3vw, 44px);
}

.footer-brand .brand-name { color: var(--warm); }
.footer-brand .brand-suffix { color: rgba(250, 246, 239, .58); }

.footer-summary {
  margin-top: 18px;
  font-size: var(--fs-16);
  line-height: 1.75;
  color: rgba(250, 246, 239, .78);
  max-width: 34ch;
}
.footer-tagline {
  margin-top: 12px;
  font-family: var(--font-mono);
  font-size: var(--fs-14);
  font-weight: 700;
  letter-spacing: .1em;
  color: var(--cyan);
}

.footer-col-title {
  font-size: 13px;
  font-weight: 900;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--cyan);
  margin-bottom: 16px;
}
.footer-links {
  display: grid;
  gap: 11px;
}
.footer-links a {
  display: inline-block;
  font-size: 15px;
  font-weight: 600;
  color: rgba(250, 246, 239, .82);
  border-bottom: 2px solid transparent;
  transition: color .16s var(--ease), border-color .16s var(--ease);
}
.footer-links a:hover,
.footer-links a:focus-visible {
  color: var(--cyan);
  border-bottom-color: var(--cyan);
}

.footer-contact {
  display: grid;
  gap: 12px;
}
.footer-contact li {
  display: grid;
  grid-template-columns: 42px 1fr;
  gap: 10px;
  align-items: start;
}
.contact-label {
  font-size: 12px;
  font-weight: 700;
  letter-spacing: .1em;
  color: rgba(250, 246, 239, .5);
  padding-top: 3px;
}
.contact-value {
  font-size: 15px;
  line-height: 1.6;
  color: rgba(250, 246, 239, .84);
  word-break: break-word;
}
.contact-value--mono {
  font-weight: 700;
  letter-spacing: -.01em;
  color: var(--warm);
}

.footer-base {
  border-top: 1px solid rgba(250, 246, 239, .16);
}
.footer-base-inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 12px 28px;
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding: 20px var(--gutter);
  font-size: 13px;
  color: rgba(250, 246, 239, .62);
}
.footer-note { line-height: 1.6; }
.footer-meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px 20px;
}
.footer-icp {
  font-weight: 700;
  letter-spacing: .02em;
  color: rgba(250, 246, 239, .78);
}
.footer-copy { white-space: nowrap; }

/* ---------- 11. 面包屑与正文列 ---------- */
.crumbs {
  font-size: var(--fs-14);
  padding-block: 18px 0;
}
.crumbs ol {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
}
.crumbs li {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  color: var(--slate);
}
.crumbs li + li::before {
  content: "/";
  color: var(--line);
  font-weight: 700;
}
.crumbs a {
  color: var(--slate);
  border-bottom: 2px solid transparent;
  transition: color .16s var(--ease), border-color .16s var(--ease);
}
.crumbs a:hover,
.crumbs a:focus-visible {
  color: var(--red);
  border-bottom-color: var(--cyan);
}
.crumbs [aria-current="page"] {
  color: var(--ink);
  font-weight: 700;
}

.prose {
  max-width: var(--wrap-narrow);
  font-size: var(--fs-18);
  line-height: 1.8;
}
.prose > * + * { margin-top: 1.1em; }
.prose h2 {
  font-size: clamp(1.5rem, 2.6vw, 2.125rem);
  font-weight: 900;
  letter-spacing: -.02em;
  line-height: 1.24;
  margin-top: 2.2em;
}
.prose h3 {
  font-size: var(--fs-22);
  font-weight: 900;
  letter-spacing: -.01em;
  line-height: 1.34;
  margin-top: 1.8em;
}
.prose ul,
.prose ol {
  padding-inline-start: 1.3em;
}
.prose ul { list-style: square; }
.prose ol { list-style: decimal; }
.prose li + li { margin-top: .5em; }
.prose strong { font-weight: 700; }
.prose blockquote {
  border-left: 4px solid var(--red);
  padding: 8px 0 8px 20px;
  color: var(--slate);
}
.prose hr {
  height: 2px;
  border: 0;
  background: var(--line);
  margin-block: 2em;
}

/* ---------- 12. 图片容器（供页面阶段放置占位图） ---------- */
.figure { margin: 0; }
.figure-frame {
  position: relative;
  background: var(--ink-2);
  border-left: 6px solid var(--red);
  overflow: hidden;
  aspect-ratio: 16 / 10;
}
.figure-frame img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}
.figure-frame--wide { aspect-ratio: 21 / 9; }
.figure-frame--square { aspect-ratio: 1 / 1; }
.figure-frame--geo {
  clip-path: polygon(0 0, calc(100% - 32px) 0, 100% 32px, 100% 100%, 32px 100%, 0 calc(100% - 32px));
}
.figure-caption {
  margin-top: 10px;
  font-size: var(--fs-14);
  line-height: 1.7;
  color: var(--slate);
}

/* ---------- 13. 章节目录与阅读辅助 ---------- */
.toc {
  position: sticky;
  top: calc(var(--header-h) + 24px);
  font-size: var(--fs-14);
}
.toc-title {
  font-size: 12px;
  font-weight: 900;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--slate);
  margin-bottom: 12px;
}
.toc-list {
  display: grid;
  gap: 2px;
}
.toc-link {
  display: block;
  padding: 8px 12px;
  border-left: 3px solid var(--line);
  font-weight: 600;
  color: var(--slate);
  transition: color .16s var(--ease), border-color .16s var(--ease), background-color .16s var(--ease);
}
.toc-link:hover {
  color: var(--ink);
  background: rgba(22, 224, 206, .12);
}
.toc-link[aria-current="true"] {
  color: var(--red);
  border-left-color: var(--red);
  background: rgba(226, 55, 43, .07);
}

.scroll-progress {
  position: fixed;
  left: 0;
  top: 0;
  width: 100%;
  height: 3px;
  background: var(--red);
  transform: scaleX(0);
  transform-origin: left center;
  pointer-events: none;
  z-index: 120;
}

.return-top {
  position: fixed;
  right: clamp(16px, 3vw, 32px);
  bottom: clamp(16px, 3vw, 32px);
  z-index: 110;
  display: grid;
  place-items: center;
  width: 50px;
  height: 50px;
  background: var(--ink);
  color: var(--warm);
  font-family: var(--font-mono);
  font-size: 16px;
  font-weight: 700;
  border: 0;
  opacity: 0;
  visibility: hidden;
  transform: translateY(10px);
  transition: opacity .2s var(--ease), transform .2s var(--ease), visibility .2s var(--ease), background-color .16s var(--ease);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 12px), calc(100% - 12px) 100%, 0 100%);
}
.return-top[data-visible] {
  opacity: 1;
  visibility: visible;
  transform: none;
}
.return-top:hover { background: var(--red); }

/* ---------- 14. 显现动效 ---------- */
[data-reveal] {
  transition: opacity .24s var(--ease), transform .24s var(--ease);
}
html[data-js="on"] [data-reveal]:not([data-revealed]) {
  opacity: 0;
  transform: translateY(24px);
}

/* ---------- 15. 响应式 ---------- */
@media (max-width: 1080px) {
  :root { --header-h: 68px; }

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

  .site-nav {
    position: fixed;
    inset: 0;
    z-index: 55;
    display: flex;
    flex-direction: column;
    align-items: stretch;
    justify-content: flex-start;
    gap: 0;
    padding: calc(var(--header-h) + 32px) var(--gutter) 40px;
    background: var(--ink);
    overflow-y: auto;
    transform: translateY(-102%);
    visibility: hidden;
    transition: transform .24s var(--ease), visibility .24s var(--ease);
  }
  .site-nav[data-open] {
    transform: none;
    visibility: visible;
  }

  .nav-list {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    border-top: 1px solid rgba(250, 246, 239, .16);
  }
  .nav-item { border-bottom: 1px solid rgba(250, 246, 239, .16); }
  .nav-link {
    display: flex;
    align-items: baseline;
    justify-content: space-between;
    gap: 16px;
    padding: 18px 4px;
    font-size: var(--fs-22);
    font-weight: 900;
    letter-spacing: -.01em;
    color: var(--warm);
  }
  .nav-link::after { display: none; }
  .nav-link:hover { color: var(--cyan); }
  .nav-link[aria-current="page"] { color: var(--cyan); }
  .nav-path {
    display: inline-block;
    font-size: 13px;
    color: rgba(250, 246, 239, .55);
    opacity: 1;
  }

  .nav-actions {
    flex-direction: column;
    align-items: stretch;
    gap: 12px;
    margin-top: 28px;
  }
  .nav-actions .btn {
    width: 100%;
    padding: 15px 20px;
    font-size: var(--fs-16);
  }
  .nav-actions .btn-ghost {
    color: var(--warm);
    border-color: rgba(250, 246, 239, .5);
  }
  .nav-actions .btn-ghost:hover,
  .nav-actions .btn-ghost:focus-visible {
    background: var(--warm);
    color: var(--ink);
    border-color: var(--warm);
  }

  .site-header[data-nav-open] {
    background: var(--ink);
    border-bottom-color: var(--red);
  }
  .site-header[data-nav-open] .brand-name { color: var(--warm); }
  .site-header[data-nav-open] .brand-suffix { color: rgba(250, 246, 239, .6); }
  .site-header[data-nav-open] .nav-toggle {
    background: var(--cyan);
    border-color: var(--cyan);
    color: var(--ink);
  }

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

  .shift-b,
  .shift-c { margin-inline-start: 0; }
}

@media (max-width: 900px) {
  .grid-3 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .grid-4 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (max-width: 640px) {
  html { scroll-padding-top: 84px; }

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

  .block-cell,
  .board-cell { border-right: 0; }

  .panel {
    padding: 24px 20px;
  }
  .sec-head { gap: 12px; }
  .sec-title { flex-basis: 100%; }

  .footer-inner {
    grid-template-columns: minmax(0, 1fr);
    padding-inline: var(--gutter);
  }
  .footer-base-inner {
    flex-direction: column;
    align-items: flex-start;
  }

  .crumbs ol { gap: 6px; }
  .return-top { width: 46px; height: 46px; }
}

/* ---------- 16. 动效降级 ---------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }

  *,
  *::before,
  *::after {
    animation-duration: .001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .001ms !important;
  }

  html[data-js="on"] [data-reveal]:not([data-revealed]) {
    opacity: 1;
    transform: none;
  }

  .site-nav {
    transition: none;
  }
  .return-top {
    transform: none;
  }
}