/* ==========================================================================
   博王主页 · 共享样式表 /assets/site.css
   预算：重置 / 变量 / 中文排版 / 通用组件 / 页头 / 页脚 / 响应式 / 动效
   ========================================================================== */

*, *::before, *::after { box-sizing: border-box; }

:root {
  /* —— 色板 —— */
  --ink-900: #10142B;
  --indigo-700: #232B5C;
  --indigo-500: #3B4691;
  --indigo-100: #E7E9F7;
  --copper-600: #A9762C;
  --copper-400: #C9A227;
  --coral-500: #FF6B4A;
  --paper-50: #F7F5F0;
  --graphite-700: #3A3F4B;
  --slate-400: #8A90A6;
  --mint-600: #1F8A70;

  /* —— 边界与材质 —— */
  --hairline: rgba(35, 43, 92, 0.22);
  --hairline-strong: rgba(35, 43, 92, 0.42);
  --hairline-copper: rgba(169, 118, 44, 0.45);
  --hairline-paper: rgba(231, 233, 247, 0.16);

  /* —— 字体 —— */
  --font-display: "Noto Serif SC", "Source Han Serif SC", "Songti SC", Georgia, "Times New Roman", serif;
  --font-body: Inter, "Noto Sans SC", -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-mono: "JetBrains Mono", "IBM Plex Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;

  /* —— 字阶 —— */
  --fs-12: 0.75rem;
  --fs-14: 0.875rem;
  --fs-16: 1rem;
  --fs-18: 1.125rem;
  --fs-24: 1.5rem;
  --fs-32: 2rem;
  --fs-44: 2.75rem;
  --fs-64: 4rem;

  /* —— 尺度 —— */
  --gutter: clamp(18px, 4vw, 40px);
  --radius-s: 8px;
  --radius-m: 14px;
  --radius-l: 22px;
  --radius-pill: 999px;
  --shadow-s: 0 2px 10px rgba(16, 20, 43, 0.06);
  --shadow-m: 0 10px 28px rgba(16, 20, 43, 0.10);
  --shadow-l: 0 20px 44px rgba(16, 20, 43, 0.16);
  --ease: cubic-bezier(0.22, 0.61, 0.36, 1);
  --shell: calc(1440px + var(--gutter) * 2);
}

/* —— 基础重置 —— */
html {
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
}

body {
  margin: 0;
  background: var(--paper-50);
  color: var(--graphite-700);
  font-family: var(--font-body);
  font-size: var(--fs-16);
  line-height: 1.75;
  font-weight: 400;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

img, svg, video { max-width: 100%; display: block; }
img { height: auto; }
ul, ol { margin: 0; padding: 0; }
button { font: inherit; color: inherit; }

h1, h2, h3, h4 {
  margin: 0 0 0.55em;
  font-family: var(--font-display);
  font-weight: 800;
  letter-spacing: -0.02em;
  line-height: 1.24;
  color: var(--indigo-700);
}

h1 { font-size: clamp(2rem, 5.2vw, var(--fs-64)); font-weight: 900; }
h2 { font-size: clamp(1.6rem, 3.4vw, var(--fs-44)); }
h3 { font-size: clamp(1.25rem, 2.2vw, var(--fs-32)); }
h4 { font-size: var(--fs-24); }

p { margin: 0 0 1em; max-width: 72ch; }

a {
  color: var(--indigo-500);
  text-decoration: none;
  text-underline-offset: 3px;
  transition: color 0.2s var(--ease);
}
a:hover { color: var(--copper-600); }

strong { color: var(--indigo-700); font-weight: 600; }

:focus-visible {
  outline: 2px solid var(--copper-400);
  outline-offset: 3px;
  border-radius: 4px;
}

[id] { scroll-margin-top: 126px; }

/* —— 跳至正文 —— */
.skip-link {
  position: absolute;
  top: -70px;
  left: 16px;
  z-index: 200;
  padding: 10px 20px;
  border-radius: var(--radius-pill);
  background: var(--ink-900);
  color: var(--paper-50);
  font-size: var(--fs-14);
  font-weight: 600;
  transition: top 0.2s var(--ease);
}
.skip-link:focus { top: 14px; color: var(--paper-50); outline-color: var(--copper-400); }

/* —— 容器与节奏 —— */
.wrap {
  width: 100%;
  max-width: var(--shell);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.section { padding-block: clamp(34px, 5.5vw, 76px); }
.section--tight { padding-block: clamp(20px, 3vw, 40px); }

.section__head {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-bottom: clamp(18px, 2.6vw, 32px);
  max-width: 64ch;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  font-weight: 500;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--copper-600);
}
.eyebrow::before {
  content: "";
  width: 24px;
  height: 1px;
  flex: none;
  background: var(--copper-400);
}

.section-title { font-size: clamp(1.6rem, 3.4vw, var(--fs-44)); margin: 0; }

.lede {
  font-size: var(--fs-18);
  line-height: 1.8;
  color: var(--indigo-500);
  max-width: 60ch;
  margin: 0;
}

.prose { max-width: 72ch; }
.prose p { max-width: none; }

.meta-mono {
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  font-weight: 500;
  letter-spacing: 0.08em;
  color: var(--slate-400);
}

.rule {
  height: 1px;
  border: 0;
  margin: 0;
  background: linear-gradient(90deg, var(--copper-400), rgba(201, 162, 39, 0));
}

/* —— 按钮 —— */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 12px 26px;
  border: 1px solid transparent;
  border-radius: var(--radius-pill);
  font-family: var(--font-body);
  font-size: var(--fs-14);
  font-weight: 600;
  line-height: 1.4;
  cursor: pointer;
  transition: transform 0.2s var(--ease), background-color 0.2s var(--ease),
    color 0.2s var(--ease), border-color 0.2s var(--ease), box-shadow 0.2s var(--ease);
}

.btn--primary {
  background: var(--coral-500);
  border-color: var(--coral-500);
  color: #FFFFFF;
}
.btn--primary:hover {
  background: #E85A3A;
  border-color: #E85A3A;
  color: #FFFFFF;
  transform: translateY(-2px);
  box-shadow: 0 12px 24px rgba(255, 107, 74, 0.28);
}

.btn--ghost {
  background: transparent;
  border-color: var(--hairline-strong);
  color: var(--indigo-700);
}
.btn--ghost:hover {
  background: var(--indigo-100);
  border-color: var(--copper-400);
  color: var(--indigo-700);
  transform: translateY(-2px);
}

.btn--copper {
  background: var(--indigo-700);
  border-color: var(--indigo-700);
  color: var(--paper-50);
}
.btn--copper:hover {
  background: var(--ink-900);
  border-color: var(--ink-900);
  color: var(--paper-50);
  transform: translateY(-2px);
  box-shadow: var(--shadow-m);
}

/* —— 标签与展签 —— */
.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 12px;
  border: 1px solid var(--hairline-copper);
  border-radius: var(--radius-pill);
  background: rgba(169, 118, 44, 0.07);
  color: var(--copper-600);
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  font-weight: 500;
  letter-spacing: 0.08em;
  line-height: 1.5;
  white-space: nowrap;
}
.tag--mint { border-color: rgba(31, 138, 112, 0.42); background: rgba(31, 138, 112, 0.08); color: var(--mint-600); }
.tag--indigo { border-color: var(--hairline); background: rgba(59, 70, 145, 0.07); color: var(--indigo-500); }
.tag--ink { border-color: rgba(201, 162, 39, 0.55); background: transparent; color: var(--copper-400); }

.plate {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 10px 18px;
  border: 1px solid var(--hairline-copper);
  border-left: 3px solid var(--copper-600);
  border-radius: 4px 10px 10px 4px;
  background: linear-gradient(90deg, rgba(169, 118, 44, 0.10), rgba(247, 245, 240, 0));
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  font-weight: 500;
  letter-spacing: 0.1em;
  color: var(--copper-600);
}

.watermark {
  position: absolute;
  right: 12px;
  bottom: -8px;
  font-family: var(--font-mono);
  font-size: clamp(1.8rem, 4.6vw, 3.4rem);
  font-weight: 500;
  letter-spacing: 0.06em;
  color: rgba(35, 43, 92, 0.08);
  pointer-events: none;
  user-select: none;
}

/* —— 卡片 —— */
.card {
  position: relative;
  padding: 24px;
  border: 1px solid var(--hairline-copper);
  border-radius: var(--radius-m);
  background: var(--paper-50);
  box-shadow: var(--shadow-s);
  transition: transform 0.24s var(--ease), box-shadow 0.24s var(--ease),
    border-color 0.24s var(--ease);
}
.card:hover,
.card:focus-within {
  transform: translateY(-2px);
  box-shadow: var(--shadow-l);
  border-color: var(--copper-400);
}

.card--ink {
  background: var(--indigo-700);
  border-color: rgba(201, 162, 39, 0.38);
  color: var(--indigo-100);
}
.card--ink .card__title { color: var(--paper-50); }
.card--ink .card__body { color: var(--indigo-100); }

.card__title {
  margin: 0 0 0.35em;
  font-family: var(--font-display);
  font-size: var(--fs-24);
  font-weight: 800;
  letter-spacing: -0.02em;
  color: var(--indigo-700);
}
.card__meta {
  display: block;
  margin-bottom: 12px;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  font-weight: 500;
  letter-spacing: 0.08em;
  color: var(--slate-400);
}
.card__body { margin: 0; font-size: var(--fs-16); }

/* —— 栅格 —— */
.grid { display: grid; gap: clamp(18px, 2.6vw, 32px); }
.grid--2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid--3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.grid--7-5 { grid-template-columns: minmax(0, 7fr) minmax(0, 5fr); }
.grid--8-4 { grid-template-columns: minmax(0, 8fr) minmax(0, 4fr); }
.grid--5-7 { grid-template-columns: minmax(0, 5fr) minmax(0, 7fr); }

/* —— 目录轴 —— */
.rail {
  position: sticky;
  top: 118px;
  align-self: start;
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: 20px 16px;
  border: 1px solid var(--hairline);
  border-radius: var(--radius-m);
  background: linear-gradient(180deg, rgba(231, 233, 247, 0.62), rgba(247, 245, 240, 0.92));
}

.rail__label {
  margin: 0 0 8px;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  font-weight: 500;
  letter-spacing: 0.16em;
  color: var(--copper-600);
}

.rail__list {
  display: flex;
  flex-direction: column;
  gap: 2px;
  list-style: none;
  margin: 0;
  padding: 0;
}

.rail-link {
  position: relative;
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 9px 12px 9px 16px;
  border-radius: var(--radius-s);
  color: var(--indigo-700);
  font-size: var(--fs-14);
  line-height: 1.5;
  transition: background-color 0.2s var(--ease), color 0.2s var(--ease),
    transform 0.2s var(--ease);
}
.rail-link::before {
  content: "";
  position: absolute;
  left: 0;
  top: 8px;
  bottom: 8px;
  width: 2px;
  border-radius: 3px;
  background: transparent;
  transition: width 0.24s var(--ease), background-color 0.24s var(--ease);
}
.rail-link:hover { background: rgba(59, 70, 145, 0.08); transform: translateX(2px); }
.rail-link.is-active { background: rgba(201, 162, 39, 0.10); color: var(--indigo-700); }
.rail-link.is-active::before { width: 6px; background: var(--copper-400); }

.rail-link__code {
  flex: none;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  font-weight: 500;
  letter-spacing: 0.06em;
  color: var(--slate-400);
}
.rail-link.is-active .rail-link__code { color: var(--copper-600); }

/* —— 图形占位容器 —— */
.media-frame {
  position: relative;
  display: block;
  overflow: hidden;
  aspect-ratio: 16 / 9;
  border: 1px solid var(--hairline-copper);
  border-radius: var(--radius-m);
  background-color: var(--indigo-100);
  background-image:
    radial-gradient(circle at 1px 1px, rgba(169, 118, 44, 0.30) 1px, transparent 1.6px),
    linear-gradient(150deg, #E7E9F7 0%, #F7F5F0 58%, #E7E9F7 100%);
  background-size: 14px 14px, 100% 100%;
}
.media-frame--tall { aspect-ratio: 4 / 5; }
.media-frame--wide { aspect-ratio: 21 / 9; }
.media-frame > img { width: 100%; height: 100%; object-fit: cover; }

/* —— 折叠面板 —— */
details.fold {
  border: 1px solid var(--hairline);
  border-radius: var(--radius-m);
  background: var(--paper-50);
  overflow: hidden;
}
details.fold + details.fold { margin-top: 10px; }
details.fold > summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 14px 18px;
  font-family: var(--font-display);
  font-size: var(--fs-18);
  font-weight: 800;
  color: var(--indigo-700);
  cursor: pointer;
  list-style: none;
}
details.fold > summary::-webkit-details-marker { display: none; }
details.fold > summary::after {
  content: "";
  flex: none;
  width: 10px;
  height: 10px;
  margin-right: 4px;
  border-right: 2px solid var(--copper-600);
  border-bottom: 2px solid var(--copper-600);
  transform: rotate(45deg);
  transition: transform 0.24s var(--ease);
}
details.fold[open] { border-left: 3px solid var(--copper-600); }
details.fold[open] > summary::after { transform: rotate(-135deg); }
details.fold .fold__body { padding: 0 18px 18px; font-size: var(--fs-16); }

/* —— 面包屑 —— */
.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin: 0;
  padding: 0;
  list-style: none;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  font-weight: 500;
  letter-spacing: 0.06em;
  color: var(--slate-400);
}
.breadcrumb li { display: flex; align-items: center; gap: 8px; }
.breadcrumb li + li::before { content: "/"; color: var(--copper-400); }
.breadcrumb a { color: var(--indigo-500); }
.breadcrumb a:hover { color: var(--copper-600); }
.breadcrumb [aria-current="page"] { color: var(--graphite-700); }

/* ==========================================================================
   页头
   ========================================================================== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 90;
  padding-bottom: 8px;
  background: linear-gradient(180deg, var(--paper-50) 62%, rgba(247, 245, 240, 0));
}

.header-inner {
  display: flex;
  flex-direction: column;
  gap: 10px;
  width: 100%;
  max-width: var(--shell);
  margin-inline: auto;
  padding: 18px var(--gutter) 0;
  transition: padding-top 0.3s var(--ease);
}

.header-meta {
  display: flex;
  align-items: center;
  gap: 12px;
  max-height: 40px;
  overflow: hidden;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  font-weight: 500;
  letter-spacing: 0.1em;
  transition: max-height 0.3s var(--ease), opacity 0.24s var(--ease),
    margin-bottom 0.3s var(--ease);
}

.brand-sig { color: var(--ink-900); letter-spacing: 0.14em; }

.ver-badge {
  padding: 2px 10px;
  border: 1px solid var(--hairline-copper);
  border-radius: var(--radius-pill);
  background: rgba(201, 162, 39, 0.12);
  color: var(--copper-600);
  letter-spacing: 0.1em;
}

.catalog-pos { margin-left: auto; color: var(--slate-400); }

.nav-shell {
  position: relative;
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 7px 8px 7px 18px;
  border: 1px solid var(--hairline);
  border-radius: var(--radius-pill);
  background: rgba(247, 245, 240, 0.88);
  -webkit-backdrop-filter: saturate(140%) blur(12px);
  backdrop-filter: saturate(140%) blur(12px);
  box-shadow: var(--shadow-s);
  transition: padding 0.3s var(--ease), box-shadow 0.3s var(--ease);
}

.brand-mark {
  display: inline-flex;
  align-items: baseline;
  gap: 8px;
  flex: none;
  font-family: var(--font-display);
  font-size: var(--fs-24);
  font-weight: 900;
  letter-spacing: -0.02em;
  color: var(--ink-900);
  white-space: nowrap;
}
.brand-mark:hover { color: var(--indigo-700); }

.brand-mark__code {
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  font-weight: 500;
  letter-spacing: 0.16em;
  color: var(--copper-600);
}

.nav-list {
  display: flex;
  align-items: center;
  gap: 2px;
  margin-left: 8px;
  list-style: none;
}

.nav-link {
  display: inline-block;
  padding: 9px 13px;
  border-radius: var(--radius-pill);
  color: var(--graphite-700);
  font-size: var(--fs-14);
  font-weight: 500;
  white-space: nowrap;
  transition: color 0.2s var(--ease), background-color 0.2s var(--ease),
    transform 0.2s var(--ease);
}
.nav-link:hover { color: var(--indigo-700); background: var(--indigo-100); transform: translateY(-2px); }
.nav-link[aria-current="page"] { color: var(--paper-50); background: var(--indigo-700); }
.nav-link[aria-current="page"]:hover { color: var(--paper-50); background: var(--ink-900); }

.cta-pill {
  display: inline-block;
  margin-left: auto;
  padding: 9px 18px;
  border: 1px solid var(--coral-500);
  border-radius: var(--radius-pill);
  color: var(--coral-500);
  font-size: var(--fs-14);
  font-weight: 600;
  white-space: nowrap;
  transition: background-color 0.2s var(--ease), color 0.2s var(--ease),
    transform 0.2s var(--ease);
}
.cta-pill:hover { background: var(--coral-500); color: #FFFFFF; transform: translateY(-2px); }

.nav-toggle {
  display: none;
  align-items: center;
  justify-content: center;
  flex: none;
  width: 42px;
  height: 42px;
  padding: 0;
  border: 1px solid var(--hairline);
  border-radius: 50%;
  background: var(--paper-50);
  cursor: pointer;
  transition: border-color 0.2s var(--ease), transform 0.2s var(--ease);
}
.nav-toggle:hover { border-color: var(--copper-400); transform: translateY(-2px); }

.nav-toggle__bars { position: relative; display: block; width: 18px; height: 12px; }

.nav-toggle__bar {
  position: absolute;
  left: 0;
  right: 0;
  height: 2px;
  border-radius: 2px;
  background: var(--indigo-700);
  transition: transform 0.24s var(--ease), opacity 0.18s var(--ease);
}
.nav-toggle__bar:nth-child(1) { top: 0; }
.nav-toggle__bar:nth-child(2) { top: 5px; }
.nav-toggle__bar:nth-child(3) { top: 10px; }

.nav-shell[data-open] .nav-toggle__bar:nth-child(1) { transform: translateY(5px) rotate(45deg); }
.nav-shell[data-open] .nav-toggle__bar:nth-child(2) { opacity: 0; }
.nav-shell[data-open] .nav-toggle__bar:nth-child(3) { transform: translateY(-5px) rotate(-45deg); }

/* 页头收窄 */
.site-header[data-compact] .header-inner { padding-top: 10px; }
.site-header[data-compact] .header-meta { max-height: 0; opacity: 0; margin-bottom: -10px; }
.site-header[data-compact] .nav-shell { padding: 5px 6px 5px 16px; box-shadow: var(--shadow-m); }

/* ==========================================================================
   页脚
   ========================================================================== */
.site-footer {
  margin-top: clamp(48px, 8vw, 112px);
  padding: clamp(38px, 5vw, 64px) 0 22px;
  border-top: 1px solid rgba(201, 162, 39, 0.42);
  background: var(--ink-900);
  color: var(--indigo-100);
}

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

.footer-grid {
  display: grid;
  grid-template-columns: 1.5fr 1fr 1fr 1.3fr;
  gap: clamp(22px, 3vw, 44px);
  padding-bottom: 34px;
  border-bottom: 1px solid var(--hairline-paper);
}

.footer-col { display: flex; flex-direction: column; }

.footer-col__title {
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  font-weight: 500;
  letter-spacing: 0.16em;
  color: var(--copper-400);
}

.footer-brand {
  display: inline-block;
  margin-bottom: 10px;
  font-family: var(--font-display);
  font-size: var(--fs-32);
  font-weight: 900;
  letter-spacing: -0.02em;
  color: var(--paper-50);
}
.footer-brand:hover { color: var(--copper-400); }

.footer-lede {
  margin: 0;
  max-width: 34ch;
  font-size: var(--fs-14);
  line-height: 1.85;
  color: var(--slate-400);
}

.footer-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
  list-style: none;
  margin: 0;
  padding: 0;
}
.footer-list--legal { margin-top: 16px; }

.footer-link {
  display: inline-block;
  color: var(--indigo-100);
  font-size: var(--fs-14);
  transition: color 0.2s var(--ease), transform 0.2s var(--ease);
}
.footer-link:hover { color: var(--copper-400); transform: translateX(3px); }
.footer-link[aria-current="page"] { color: var(--copper-400); }

.footer-contact {
  display: flex;
  flex-direction: column;
  gap: 6px;
  margin: 0;
  font-style: normal;
  font-size: var(--fs-14);
  line-height: 1.8;
  color: var(--indigo-100);
}
.footer-contact__line { word-break: break-word; }

.footer-note {
  margin-top: 10px;
  font-size: var(--fs-12);
  line-height: 1.7;
  color: var(--slate-400);
}

.footer-bottom {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px 20px;
  padding-top: 20px;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  font-weight: 500;
  letter-spacing: 0.06em;
  color: var(--slate-400);
}

.footer-icp { margin-left: auto; }

/* ==========================================================================
   滚动显现
   ========================================================================== */
.reveal {
  opacity: 0;
  transform: translateY(12px);
  transition: opacity 0.42s var(--ease), transform 0.42s var(--ease);
}
.reveal.is-in { opacity: 1; transform: none; }

/* ==========================================================================
   响应式
   ========================================================================== */
@media (max-width: 1535px) {
  .grid--7-5 { grid-template-columns: minmax(0, 6fr) minmax(0, 5fr); }
}

@media (max-width: 1279px) {
  .rail { top: 108px; padding: 16px 12px; }
}

@media (max-width: 1023px) {
  .nav-toggle { display: inline-flex; }

  .nav-list {
    position: absolute;
    top: calc(100% + 12px);
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: stretch;
    gap: 4px;
    margin: 0;
    padding: 10px;
    border: 1px solid var(--hairline);
    border-radius: var(--radius-l);
    background: var(--paper-50);
    box-shadow: var(--shadow-l);
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: opacity 0.24s var(--ease), transform 0.24s var(--ease),
      visibility 0.24s var(--ease);
  }
  .nav-shell[data-open] .nav-list {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
  }
  .nav-link { padding: 11px 14px; font-size: var(--fs-16); }
  .nav-link:hover { transform: none; }
  .cta-pill { padding: 8px 14px; font-size: var(--fs-12); }

  .grid--7-5,
  .grid--8-4,
  .grid--5-7,
  .grid--3 { grid-template-columns: minmax(0, 1fr); }

  .rail {
    position: static;
    flex-direction: row;
    align-items: center;
    gap: 10px;
    padding: 10px 12px;
    overflow-x: auto;
  }
  .rail__label { margin: 0; flex: none; }
  .rail__list { flex-direction: row; gap: 6px; }
  .rail-link { white-space: nowrap; padding: 8px 12px; }
  .rail-link::before { display: none; }
  .rail-link:hover { transform: none; }

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

@media (max-width: 767px) {
  body { font-size: var(--fs-16); }
  .grid--2 { grid-template-columns: minmax(0, 1fr); }
  .card { padding: 20px; }
  details.fold > summary { font-size: var(--fs-16); }
  .footer-grid { gap: 26px; }
}

@media (max-width: 479px) {
  .cta-pill { display: none; }
  .header-meta { gap: 10px; }
  .brand-mark { font-size: var(--fs-18); }
  .brand-mark__code { display: none; }
  .footer-grid { grid-template-columns: minmax(0, 1fr); }
  .footer-brand { font-size: var(--fs-24); }
  .btn { width: 100%; justify-content: center; }
}

/* ==========================================================================
   动效降级
   ========================================================================== */
@media (prefers-reduced-motion: no-preference) {
  html { scroll-behavior: smooth; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reveal {
    transform: none;
    transition: opacity 0.12s linear;
  }
  .card:hover,
  .card:focus-within,
  .btn:hover,
  .nav-link:hover,
  .cta-pill:hover,
  .nav-toggle:hover,
  .rail-link:hover,
  .footer-link:hover {
    transform: none;
  }
  .rail-link::before { transition: none; }
  .nav-list,
  .header-meta,
  .header-inner,
  .nav-shell { transition: none; }
}