/* ==========================================================================
   365在线 · 共享站点样式 /assets/site.css
   纸感手册：reset → 变量 → 基础排版 → 布局与工具 → 页头 → 页脚 → 组件 → 响应式
   ========================================================================== */

/* ---------- 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, 72px) + 16px);
}

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

ol, ul { padding: 0; }

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

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

a { color: inherit; }

table { border-collapse: collapse; width: 100%; }

/* ---------- 变量 ---------- */
:root {
  /* 色板 */
  --paper: #F7F3EB;
  --sand: #EBE3D6;
  --card: #FDFAF4;
  --ink: #24231F;
  --charcoal: #55524A;
  --orange: #FF7A1A;
  --orange-deep: #D95F0B;
  --orange-soft: #FFE9D8;
  --blue: #3E5C76;
  --blue-mid: #6E8AA3;
  --blue-soft: #E4EBF1;
  --green: #1E6B57;
  --clay: #A5432F;
  --line-paper: #D8D0C2;
  --line-cool: #C9D3DC;

  /* 材质 */
  --shadow: 0 1px 2px rgba(36, 35, 31, .06);
  --shadow-lift: 0 6px 20px rgba(36, 35, 31, .08);
  --radius: 2px;
  --radius-md: 4px;

  /* 尺寸与节奏 */
  --header-h: 72px;
  --wrap: 1180px;
  --gutter: clamp(16px, 4vw, 32px);
  --section-gap: clamp(56px, 8vw, 96px);

  /* 字体 */
  --font-display: "Source Han Sans SC", "Noto Sans SC", system-ui, -apple-system, "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-body: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", "Source Han Sans SC", system-ui, sans-serif;
  --font-mono: ui-monospace, "JetBrains Mono", Menlo, Consolas, "Courier New", monospace;

  /* 动效 */
  --ease: cubic-bezier(.2, .8, .2, 1);
  --t-fast: 160ms;
  --t-base: 240ms;
}

/* ---------- 基础排版 ---------- */
body {
  min-height: 100vh;
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.85;
  color: var(--charcoal);
  background-color: var(--paper);
  background-image:
    radial-gradient(120% 55% at 50% -12%, rgba(255, 255, 255, .68), rgba(255, 255, 255, 0) 62%),
    repeating-linear-gradient(0deg, rgba(36, 35, 31, .022) 0 1px, rgba(36, 35, 31, 0) 1px 5px);
  background-attachment: fixed;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-display);
  font-weight: 800;
  line-height: 1.25;
  letter-spacing: -.01em;
  color: var(--ink);
}

p { max-width: 40em; }

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

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

:focus-visible {
  outline: 2px solid var(--orange-deep);
  outline-offset: 3px;
  border-radius: var(--radius);
}

/* ---------- 工具类 ---------- */
.sr-only {
  position: absolute;
  width: 1px; height: 1px;
  padding: 0; margin: -1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
  border: 0;
}

.skip-link {
  position: fixed;
  top: 10px;
  left: 12px;
  z-index: 200;
  padding: 10px 16px;
  font-size: 13px;
  font-weight: 700;
  color: var(--paper);
  background: var(--ink);
  border-radius: var(--radius);
  text-decoration: none;
  transform: translateY(-220%);
  transition: transform 180ms var(--ease);
}
.skip-link:focus,
.skip-link:focus-visible { transform: none; color: var(--paper); }

/* ---------- 布局容器 ---------- */
.container {
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding-inline: var(--gutter);
}
.container--narrow { max-width: 780px; }

.section { padding-block: var(--section-gap); }
.section--tight { padding-block: clamp(32px, 5vw, 56px); }

.band {
  padding-block: clamp(32px, 5vw, 56px);
  background: var(--sand);
  border-top: 1px solid var(--line-paper);
  border-bottom: 1px solid var(--line-paper);
}

.divider {
  height: 1px;
  border: 0;
  margin-block: clamp(24px, 4vw, 40px);
  background: var(--line-paper);
}

.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--rail {
  grid-template-columns: minmax(0, 240px) minmax(0, 1fr);
  gap: clamp(24px, 4vw, 56px);
  align-items: start;
}

/* 左侧固定索引栏（页面阶段使用） */
.rail {
  position: sticky;
  top: calc(var(--header-h) + 20px);
  align-self: start;
  padding-right: 16px;
  border-right: 1px solid var(--line-paper);
}
.rail-title {
  font-family: var(--font-mono);
  font-size: 11.5px;
  font-weight: 600;
  letter-spacing: .14em;
  color: var(--blue);
  margin-bottom: 10px;
}
.rail-list { list-style: none; display: flex; flex-direction: column; gap: 2px; }
.rail-link {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 7px 8px;
  font-size: 13.5px;
  color: var(--charcoal);
  text-decoration: none;
  border-left: 2px solid transparent;
  transition: background-color var(--t-fast) var(--ease), color var(--t-fast) var(--ease);
}
.rail-link:hover { color: var(--ink); background: rgba(235, 227, 214, .65); }
.rail-link[aria-current="page"] {
  color: var(--ink);
  font-weight: 700;
  border-left-color: var(--orange);
  background: var(--orange-soft);
}
.rail-num { font-family: var(--font-mono); font-size: 11px; letter-spacing: .08em; color: var(--blue-mid); }
.rail-link[aria-current="page"] .rail-num { color: var(--orange-deep); }

/* ---------- 标题与编号 ---------- */
.title-group {
  display: flex;
  align-items: baseline;
  flex-wrap: wrap;
  gap: 4px 0;
}
.title-display {
  font-size: clamp(30px, 4.2vw, 40px);
  font-weight: 800;
}
.title-section { font-size: clamp(22px, 2.6vw, 28px); }
.title-sub { font-size: 20px; font-weight: 700; }

.index-num {
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 600;
  letter-spacing: .06em;
  color: var(--orange-deep);
  font-variant-numeric: tabular-nums;
}
.title-sep {
  display: inline-block;
  width: 1px;
  height: .82em;
  margin-inline: .7em;
  background: var(--line-paper);
  vertical-align: -.04em;
}
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 600;
  letter-spacing: .16em;
  color: var(--blue);
  text-transform: uppercase;
}
.eyebrow::before {
  content: "";
  width: 18px;
  height: 2px;
  background: var(--orange);
  flex: 0 0 auto;
}

.stat {
  font-family: var(--font-display);
  font-size: clamp(32px, 4vw, 48px);
  font-weight: 800;
  line-height: 1.1;
  letter-spacing: -.02em;
  color: var(--ink);
  font-variant-numeric: tabular-nums;
}
.stat-label {
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .12em;
  color: var(--blue);
}

/* ---------- 正文 ---------- */
.prose {
  max-width: 34em;
  font-size: 16px;
  line-height: 1.85;
  color: var(--charcoal);
}
.prose p + p { margin-top: 1.2em; }
.prose h3 { font-size: 20px; margin-top: 1.6em; margin-bottom: .4em; }
.prose ul, .prose ol { margin: 1em 0 0 1.2em; display: flex; flex-direction: column; gap: .35em; }
.prose a {
  color: var(--blue);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
  text-decoration-color: rgba(62, 92, 118, .38);
}
.prose a:hover { color: var(--orange-deep); text-decoration-color: rgba(217, 95, 11, .45); }

/* ---------- 面包屑 ---------- */
.breadcrumb {
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .08em;
  color: var(--blue-mid);
}
.breadcrumb ol { display: flex; flex-wrap: wrap; align-items: center; gap: 0 8px; list-style: none; }
.breadcrumb li { display: inline-flex; align-items: center; gap: 8px; }
.breadcrumb li + li::before { content: "/"; color: var(--line-cool); }
.breadcrumb a {
  color: var(--blue);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color var(--t-fast) var(--ease), border-color var(--t-fast) var(--ease);
}
.breadcrumb a:hover { color: var(--orange-deep); border-bottom-color: rgba(217, 95, 11, .4); }
.breadcrumb [aria-current="page"] { color: var(--ink); }

/* ---------- 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 11px 18px;
  font-size: 14px;
  font-weight: 600;
  line-height: 1.4;
  text-decoration: none;
  border: 1px solid transparent;
  border-radius: var(--radius);
  cursor: pointer;
  transition: background-color var(--t-fast) var(--ease),
              color var(--t-fast) var(--ease),
              border-color var(--t-fast) var(--ease),
              transform var(--t-fast) var(--ease);
}
.btn--primary {
  background: var(--orange);
  border-color: var(--orange-deep);
  color: var(--ink);
  box-shadow: var(--shadow);
}
.btn--primary:hover { background: var(--orange-deep); color: #FFFFFF; }
.btn--ghost {
  background: transparent;
  border-color: rgba(217, 95, 11, .45);
  color: var(--orange-deep);
}
.btn--ghost:hover { background: var(--orange-soft); }
.btn--quiet {
  background: var(--card);
  border-color: var(--line-cool);
  color: var(--blue);
}
.btn--quiet:hover { border-color: var(--blue-mid); }
.btn:active { transform: translateY(1px); }

/* ---------- 标签 ---------- */
.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 2px 9px;
  font-size: 12px;
  line-height: 1.6;
  border-radius: 999px;
  background: var(--orange-soft);
  border: 1px solid rgba(217, 95, 11, .28);
  color: var(--orange-deep);
}
.tag--old {
  background: var(--blue-soft);
  border-color: var(--line-cool);
  color: var(--blue);
}
.tag--ok {
  background: #E7F1EC;
  border-color: rgba(30, 107, 87, .28);
  color: var(--green);
}

/* ---------- 卡片 / 研究板 ---------- */
.card {
  padding: clamp(16px, 2.2vw, 24px);
  background: var(--card);
  border: 1px solid var(--line-paper);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow);
}
.card--flat { box-shadow: none; }

.panel {
  background: var(--card);
  border: 1px solid var(--line-paper);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow);
  overflow: hidden;
}
.panel-head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 10px;
  padding: 16px 20px;
  border-bottom: 1px solid var(--line-paper);
  background: linear-gradient(180deg, rgba(255, 255, 255, .62), rgba(255, 255, 255, 0));
}
.panel-body { padding: 20px; }
.panel-block { padding: 16px 20px; border-top: 1px solid var(--line-paper); }
.panel-block:first-child { border-top: 0; }

/* ---------- 旧版说明 / 提示 ---------- */
.note {
  padding: 14px 16px;
  font-size: 14px;
  color: var(--charcoal);
  background: var(--blue-soft);
  border-left: 2px solid var(--blue);
  border-radius: 0 var(--radius) var(--radius) 0;
}
.note-label {
  display: block;
  margin-bottom: 6px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .12em;
  color: var(--blue);
}
.note--warn { background: #FBEDE8; border-left-color: var(--clay); }
.note--warn .note-label { color: var(--clay); }

/* ---------- 新旧对照 ---------- */
.compare {
  display: grid;
  grid-template-columns: 46fr 54fr;
  background: var(--card);
  border: 1px solid var(--line-paper);
  border-radius: var(--radius-md);
  overflow: hidden;
}
.compare-col { padding: 18px 20px; }
.compare-col + .compare-col { border-left: 1px solid var(--line-cool); }
.compare-col--old { background: var(--blue-soft); }
.compare-head {
  margin-bottom: 10px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .12em;
  color: var(--blue);
}

/* ---------- 图片容器 ---------- */
.media {
  position: relative;
  display: block;
  width: 100%;
  overflow: hidden;
  background: var(--sand);
  border: 1px solid var(--line-paper);
  border-radius: var(--radius);
}
.media img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  filter: saturate(.55) contrast(1.03) sepia(.06);
}
.media--wide { aspect-ratio: 16 / 9; }
.media--square { aspect-ratio: 1 / 1; }
.media--tall { aspect-ratio: 3 / 4; }
.media--strip { aspect-ratio: 21 / 9; }
.media--empty {
  background-image:
    repeating-linear-gradient(45deg, rgba(62, 92, 118, .10) 0 1px, rgba(62, 92, 118, 0) 1px 10px);
  background-color: var(--blue-soft);
  border-color: var(--line-cool);
}
.media-cap {
  margin-top: 8px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .04em;
  color: var(--blue-mid);
}

/* ---------- 筛选条 ---------- */
.filter-bar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  padding-bottom: 14px;
  border-bottom: 1px solid var(--line-paper);
}
.filter-btn {
  padding: 7px 14px;
  font-size: 13px;
  font-weight: 600;
  color: var(--charcoal);
  background: var(--card);
  border: 1px solid var(--line-paper);
  border-radius: 999px;
  cursor: pointer;
  transition: color var(--t-fast) var(--ease),
              border-color var(--t-fast) var(--ease),
              background-color var(--t-fast) var(--ease);
}
.filter-btn:hover { color: var(--orange-deep); border-color: var(--orange); }
.filter-btn[aria-pressed="true"] {
  background: var(--orange);
  border-color: var(--orange-deep);
  color: var(--ink);
}
.filter-status {
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .08em;
  color: var(--blue-mid);
}
.filter-item[hidden] { display: none; }
.filter-item.is-in { animation: filterIn var(--t-fast) var(--ease) both; }
@keyframes filterIn {
  from { opacity: 0; transform: translateY(4px); }
  to { opacity: 1; transform: none; }
}

/* ---------- 折叠 ---------- */
.accordion { border-top: 1px solid var(--line-paper); }
.accordion-item { border-bottom: 1px solid var(--line-paper); }
.accordion-trigger {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  width: 100%;
  padding: 16px 4px;
  font-size: 16px;
  font-weight: 700;
  font-family: var(--font-display);
  text-align: left;
  color: var(--ink);
  background: transparent;
  border: 0;
  cursor: pointer;
}
.accordion-trigger::after {
  content: "+";
  font-family: var(--font-mono);
  font-size: 18px;
  line-height: 1;
  color: var(--orange-deep);
}
.accordion-trigger[aria-expanded="true"]::after { content: "–"; }
.accordion-panel { padding: 0 4px 18px; font-size: 15px; color: var(--charcoal); }
.accordion-panel[hidden] { display: none; }

/* ==========================================================================
   页头
   ========================================================================== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 80;
  background: rgba(247, 243, 235, .74);
  -webkit-backdrop-filter: blur(12px) saturate(1.05);
  backdrop-filter: blur(12px) saturate(1.05);
  border-bottom: 1px solid transparent;
  transition: background-color var(--t-base) var(--ease),
              border-color var(--t-base) var(--ease),
              box-shadow var(--t-base) var(--ease);
}
.site-header[data-state="solid"] {
  background: var(--paper);
  border-bottom-color: var(--line-paper);
  box-shadow: var(--shadow);
}

.header-inner {
  display: flex;
  align-items: center;
  gap: clamp(12px, 2vw, 24px);
  width: 100%;
  max-width: 1280px;
  min-height: var(--header-h);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

/* 品牌 */
.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  flex: 0 0 auto;
  text-decoration: none;
  color: var(--ink);
}
.brand-mark {
  display: inline-grid;
  place-items: center;
  width: 38px;
  height: 38px;
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: .02em;
  color: var(--ink);
  background: var(--orange);
  border-radius: var(--radius) 9px var(--radius) var(--radius);
  box-shadow: inset 0 -2px 0 rgba(36, 35, 31, .14);
  transition: background-color var(--t-fast) var(--ease), color var(--t-fast) var(--ease);
}
.brand:hover .brand-mark { background: var(--orange-deep); color: #FFFFFF; }
.brand-text { display: flex; flex-direction: column; line-height: 1.2; }
.brand-name {
  font-family: var(--font-display);
  font-size: 16px;
  font-weight: 800;
  letter-spacing: -.01em;
  color: var(--ink);
}
.brand-tag {
  font-size: 11px;
  letter-spacing: .02em;
  color: var(--blue);
}

/* 移动端按钮（桌面隐藏） */
.nav-toggle {
  display: none;
  align-items: center;
  gap: 8px;
  margin-left: auto;
  padding: 9px 12px;
  font-size: 13px;
  font-weight: 700;
  color: var(--ink);
  background: var(--card);
  border: 1px solid var(--line-paper);
  border-radius: var(--radius);
  cursor: pointer;
  transition: border-color var(--t-fast) var(--ease), background-color var(--t-fast) var(--ease);
}
.nav-toggle:hover { border-color: var(--orange); background: var(--orange-soft); }
.nav-toggle-bars {
  position: relative;
  width: 16px;
  height: 10px;
  border-top: 2px solid var(--orange-deep);
  border-bottom: 2px solid var(--orange-deep);
}
.nav-toggle-bars::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  top: 50%;
  height: 2px;
  margin-top: -1px;
  background: var(--orange-deep);
  transition: opacity var(--t-fast) var(--ease);
}
.nav-toggle[aria-expanded="true"] .nav-toggle-bars::after { opacity: 0; }
.nav-toggle-label { white-space: nowrap; }

/* 导航 */
.site-nav {
  display: flex;
  align-items: center;
  gap: clamp(8px, 1.4vw, 18px);
  margin-left: auto;
}
.nav-list {
  display: flex;
  align-items: center;
  gap: 2px;
  list-style: none;
}
.nav-link {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 1px;
  padding: 10px 10px 12px;
  text-decoration: none;
  color: var(--charcoal);
  border-radius: var(--radius);
  transition: color var(--t-fast) var(--ease), background-color var(--t-fast) var(--ease);
}
.nav-num {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: .14em;
  color: var(--blue-mid);
  font-variant-numeric: tabular-nums;
}
.nav-text { font-size: 13.5px; font-weight: 600; white-space: nowrap; }
.nav-link::after {
  content: "";
  position: absolute;
  left: 10px;
  right: 10px;
  bottom: 4px;
  height: 2px;
  background: var(--orange);
  transform: scaleX(0);
  transform-origin: left center;
  transition: transform var(--t-base) var(--ease);
}
.nav-link:hover { color: var(--ink); background: rgba(235, 227, 214, .7); }
.nav-link:hover::after { transform: scaleX(1); }
.nav-link[aria-current="page"] {
  color: var(--ink);
  background: rgba(255, 233, 216, .78);
}
.nav-link[aria-current="page"]::after { transform: scaleX(1); }
.nav-link[aria-current="page"] .nav-num { color: var(--orange-deep); }

.nav-action {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 14px;
  font-size: 13px;
  font-weight: 700;
  white-space: nowrap;
  text-decoration: none;
  color: var(--orange-deep);
  background: rgba(255, 233, 216, .55);
  border: 1px solid rgba(217, 95, 11, .45);
  border-radius: 999px;
  transition: background-color var(--t-fast) var(--ease),
              color var(--t-fast) var(--ease),
              border-color var(--t-fast) var(--ease);
}
.nav-action:hover { background: var(--orange); border-color: var(--orange-deep); color: var(--ink); }

/* 阅读进度线 */
.scroll-progress {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 2px;
  pointer-events: none;
}
.scroll-progress-bar {
  display: block;
  width: 0;
  height: 100%;
  background: linear-gradient(90deg, var(--orange), var(--orange-deep));
  transition: width 120ms linear;
}

/* ==========================================================================
   页脚
   ========================================================================== */
.site-footer {
  margin-top: var(--section-gap);
  color: var(--charcoal);
  background: var(--sand);
  border-top: 1px solid var(--line-paper);
}
.footer-inner {
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding: clamp(40px, 6vw, 72px) var(--gutter) 24px;
}
.footer-top {
  display: grid;
  grid-template-columns: minmax(200px, .92fr) minmax(0, 2fr);
  gap: clamp(28px, 5vw, 64px);
}

.footer-brand-mark {
  display: inline-grid;
  place-items: center;
  width: 44px;
  height: 44px;
  font-family: var(--font-mono);
  font-size: 14px;
  font-weight: 700;
  color: var(--paper);
  background: var(--ink);
  border-radius: var(--radius) 10px var(--radius) var(--radius);
}
.footer-brand-name {
  margin-top: 14px;
  font-family: var(--font-display);
  font-size: 20px;
  font-weight: 800;
  color: var(--ink);
}
.footer-brand-tag { font-size: 13px; letter-spacing: .02em; color: var(--blue); }
.footer-brand-note {
  max-width: 26em;
  margin-top: 14px;
  padding-top: 14px;
  font-size: 13.5px;
  line-height: 1.85;
  color: var(--charcoal);
  border-top: 1px dashed var(--line-paper);
}

.footer-cols {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: clamp(20px, 3vw, 36px);
}
.footer-col-title {
  position: relative;
  margin-bottom: 12px;
  padding-bottom: 8px;
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 600;
  letter-spacing: .14em;
  color: var(--blue);
  border-bottom: 1px solid var(--line-paper);
}
.footer-col-title::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -1px;
  width: 28px;
  height: 2px;
  background: var(--orange);
}
.footer-links { display: flex; flex-direction: column; gap: 2px; list-style: none; }
.footer-link {
  display: inline-block;
  padding: 5px 0;
  font-size: 14px;
  color: var(--charcoal);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color var(--t-fast) var(--ease), border-color var(--t-fast) var(--ease);
}
.footer-link:hover { color: var(--orange-deep); border-bottom-color: rgba(217, 95, 11, .4); }

.footer-contact {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 28px;
  margin-top: clamp(32px, 4vw, 52px);
  padding-top: 20px;
  border-top: 1px solid var(--line-paper);
}
.contact-item { display: inline-flex; align-items: center; gap: 8px; font-size: 13px; }
.contact-label {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .1em;
  color: var(--blue-mid);
}
.contact-value {
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: .02em;
  color: var(--ink);
  word-break: break-word;
}
.copy-btn {
  padding: 2px 9px;
  font-size: 11.5px;
  line-height: 1.6;
  color: var(--blue);
  background: var(--card);
  border: 1px solid var(--line-cool);
  border-radius: 999px;
  cursor: pointer;
  transition: color var(--t-fast) var(--ease),
              border-color var(--t-fast) var(--ease),
              background-color var(--t-fast) var(--ease);
}
.copy-btn:hover { color: var(--orange-deep); border-color: var(--orange); background: var(--orange-soft); }
.copy-btn[data-copied] { color: var(--green); border-color: var(--green); background: #E7F1EC; }

.footer-meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 12px 20px;
  margin-top: 24px;
  padding-top: 16px;
  border-top: 1px solid var(--line-paper);
}
.footer-legal {
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .06em;
  color: var(--blue);
}
.footer-actions { display: flex; flex-wrap: wrap; align-items: center; gap: 10px 14px; }
.copy-status { font-size: 12px; color: var(--green); }
.copy-status:empty { display: none; }
.to-top {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 7px 12px;
  font-size: 12.5px;
  color: var(--blue);
  background: var(--card);
  border: 1px solid var(--line-cool);
  border-radius: var(--radius);
  cursor: pointer;
  transition: color var(--t-fast) var(--ease),
              border-color var(--t-fast) var(--ease),
              background-color var(--t-fast) var(--ease);
}
.to-top:hover { color: var(--orange-deep); border-color: var(--orange); background: var(--orange-soft); }
.to-top-num { font-family: var(--font-mono); font-size: 11px; color: var(--orange-deep); }
.to-top-num:empty { display: none; }

/* ==========================================================================
   响应式
   ========================================================================== */
@media (max-width: 1079px) {
  html[data-nav-open] { overflow: hidden; }

  .grid--rail { grid-template-columns: minmax(0, 1fr); }
  .rail {
    position: static;
    padding-right: 0;
    padding-bottom: 12px;
    border-right: 0;
    border-bottom: 1px solid var(--line-paper);
  }

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

  .site-nav {
    position: fixed;
    top: var(--header-h);
    left: 0;
    right: 0;
    z-index: 79;
    display: flex;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    max-height: calc(100vh - var(--header-h));
    margin: 0;
    padding: 8px var(--gutter) 22px;
    overflow-y: auto;
    background: var(--paper);
    border-bottom: 1px solid var(--line-paper);
    box-shadow: var(--shadow-lift);
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
    transform: translateY(-10px);
    transition: opacity 220ms var(--ease),
                transform 220ms var(--ease),
                visibility 220ms var(--ease);
  }
  .site-nav[data-open] {
    opacity: 1;
    visibility: visible;
    pointer-events: auto;
    transform: none;
  }
  .nav-list { flex-direction: column; align-items: stretch; gap: 0; }
  .nav-item + .nav-item { border-top: 1px solid var(--line-paper); }
  .nav-link {
    flex-direction: row;
    align-items: baseline;
    gap: 12px;
    padding: 14px 2px;
    border-radius: 0;
  }
  .nav-link:hover { background: transparent; }
  .nav-link::after { display: none; }
  .nav-link[aria-current="page"] { background: transparent; }
  .nav-link[aria-current="page"] .nav-text { color: var(--orange-deep); }
  .nav-text { font-size: 15px; white-space: normal; }
  .nav-num { width: 24px; flex: 0 0 auto; font-size: 11px; }
  .nav-action { align-self: flex-start; margin-top: 16px; }
}

@media (max-width: 900px) {
  .footer-top { grid-template-columns: minmax(0, 1fr); }
}

@media (max-width: 760px) {
  :root { --section-gap: 56px; }

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

  .compare { grid-template-columns: minmax(0, 1fr); }
  .compare-col + .compare-col { border-left: 0; border-top: 1px solid var(--line-cool); }

  .panel-body { padding: 16px; }
  .panel-head { padding: 14px 16px; }
  .panel-block { padding: 14px 16px; }

  .footer-contact { flex-direction: column; align-items: flex-start; gap: 8px; }
  .footer-meta { justify-content: flex-start; }
}

@media (max-width: 620px) {
  .footer-cols { grid-template-columns: minmax(0, 1fr); gap: 22px; }
  .footer-col + .footer-col { padding-top: 18px; border-top: 1px dashed var(--line-paper); }
}

@media (max-width: 560px) {
  :root { --header-h: 62px; }
  .brand-tag { display: none; }
  .brand-mark { width: 34px; height: 34px; font-size: 12px; }
  .filter-status { width: 100%; margin-left: 0; }
  .contact-value { font-size: 12px; }
}

/* ---------- 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;
  }
  .filter-item.is-in { animation: none; }
  .scroll-progress-bar { transition: none; }
}