/* =====================================================================
   四季官方 · 共享样式 /assets/site.css
   ===================================================================== */

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

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

body, h1, h2, h3, h4, h5, h6,
p, ul, ol, li, figure, figcaption, blockquote, dl, dt, dd, fieldset, legend, pre {
  margin: 0;
  padding: 0;
}

ul, ol { list-style: none; }

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

a { color: inherit; text-decoration: none; }

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

button { background: none; border: 0; cursor: pointer; }

table { border-collapse: collapse; border-spacing: 0; width: 100%; }

hr { border: 0; border-top: 2px solid var(--line); }

/* ---------- 2. 变量 ---------- */
:root {
  --bg: #070B14;
  --panel: #0E1524;
  --panel-2: #0B1220;
  --line: #1B2A44;

  --ink: #EDF2FA;
  --ink-2: #8C9BB6;
  --ink-3: #5B6A86;

  --spring: #2BE08A;
  --summer: #FF8A3C;
  --autumn: #F2C14E;
  --winter: #4C8DFF;
  --alert: #FF5470;

  --grad-seasons: linear-gradient(100deg, #2BE08A 0%, #F2C14E 34%, #FF8A3C 62%, #4C8DFF 100%);
  --grad-glow: linear-gradient(180deg, rgba(76,141,255,.16), rgba(7,11,20,0) 70%);

  --rail-w: 264px;
  --topbar-h: 64px;
  --shell-max: 1280px;

  --hard: 6px 6px 0 var(--line);
  --hard-sm: 4px 4px 0 var(--line);

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

  --ease: cubic-bezier(.2, .7, .3, 1);
  --dur: 180ms;
}

/* ---------- 3. 基础排版 ---------- */
body {
  min-height: 100vh;
  padding-left: var(--rail-w);
  background-color: var(--bg);
  background-image:
    radial-gradient(1100px 620px at 12% -10%, rgba(76,141,255,.10), transparent 62%),
    radial-gradient(900px 520px at 96% 4%, rgba(43,224,138,.07), transparent 60%);
  background-repeat: no-repeat;
  color: var(--ink);
  font-family: var(--font-body);
  font-size: 16px;
  font-weight: 400;
  line-height: 1.75;
  letter-spacing: .01em;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}

body.is-locked { overflow: hidden; }

p { max-width: 72ch; text-align: left; }

strong { font-weight: 700; }

::selection { background: var(--autumn); color: #05080F; }

/* ---------- 4. 工具类 ---------- */
.sr-only {
  position: absolute;
  width: 1px; height: 1px;
  margin: -1px; padding: 0;
  overflow: hidden;
  clip: rect(0 0 0 0);
  clip-path: inset(50%);
  white-space: nowrap;
  border: 0;
}

.shell {
  width: 100%;
  max-width: var(--shell-max);
  margin: 0 auto;
  padding: 0 40px;
}

.mono-num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-feature-settings: "tnum" 1;
  letter-spacing: 0;
}

.eyebrow {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .18em;
  text-transform: uppercase;
  color: var(--ink-2);
}

.section-num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-weight: 600;
  font-size: clamp(28px, 4vw, 56px);
  line-height: 1;
  letter-spacing: -.02em;
  color: var(--autumn);
}

.display {
  font-size: clamp(44px, 7vw, 128px);
  font-weight: 200;
  line-height: .94;
  letter-spacing: -.02em;
  text-wrap: balance;
}

.section-head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 16px 24px;
  margin-bottom: 28px;
}

.section-head .eyebrow { flex: 0 0 100%; }

.page-head {
  padding: 72px 0 40px;
  border-bottom: 2px solid var(--line);
}

.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-bottom: 22px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .18em;
  text-transform: uppercase;
  color: var(--ink-2);
}

.breadcrumb a { color: var(--winter); }
.breadcrumb a:hover { color: var(--spring); }
.breadcrumb li::after { content: "/"; margin-left: 10px; color: var(--ink-3); }
.breadcrumb li:last-child::after { content: ""; margin: 0; }

.gradient-rule {
  height: 3px;
  border: 0;
  background: var(--grad-seasons);
}

/* ---------- 5. 焦点 ---------- */
:focus-visible {
  outline: 3px solid var(--winter);
  outline-offset: 3px;
}

/* ---------- 6. 跳转链接 ---------- */
.skip-link {
  position: fixed;
  top: -120px;
  left: 16px;
  z-index: 300;
  padding: 12px 20px;
  background: var(--winter);
  color: #04101F;
  font-weight: 700;
  letter-spacing: .04em;
  border: 2px solid var(--ink);
  transition: top var(--dur) var(--ease);
}

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

/* ---------- 7. 框架式头部 ---------- */
.site-header {
  position: fixed;
  top: 0;
  bottom: 0;
  left: 0;
  z-index: 80;
  display: flex;
  flex-direction: column;
  width: var(--rail-w);
  background: var(--panel);
  border-right: 2px solid var(--line);
}

.rail-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 22px 20px;
  border-bottom: 2px solid var(--line);
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  min-width: 0;
}

.brand-mark {
  display: grid;
  grid-template-columns: repeat(2, 10px);
  grid-template-rows: repeat(2, 10px);
  gap: 3px;
  flex: none;
}

.brand-mark i { display: block; width: 10px; height: 10px; }
.brand-mark i:nth-child(1) { background: var(--spring); }
.brand-mark i:nth-child(2) { background: var(--summer); }
.brand-mark i:nth-child(3) { background: var(--autumn); }
.brand-mark i:nth-child(4) { background: var(--winter); }

.brand-body {
  display: flex;
  flex-direction: column;
  min-width: 0;
}

.brand-name {
  font-size: 20px;
  font-weight: 700;
  letter-spacing: .08em;
  line-height: 1.2;
  color: var(--ink);
}

.brand-tag {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: .14em;
  color: var(--ink-2);
  white-space: nowrap;
}

/* 移动端按钮 */
.nav-toggle {
  display: none;
  align-items: center;
  gap: 10px;
  padding: 10px 12px;
  color: var(--ink);
  border: 2px solid var(--line);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .18em;
  text-transform: uppercase;
}

.nav-toggle-bars {
  position: relative;
  display: block;
  width: 18px;
  height: 12px;
  flex: none;
}

.nav-toggle-bars i {
  position: absolute;
  left: 0;
  width: 100%;
  height: 2px;
  background: currentColor;
  transition: transform var(--dur) var(--ease), opacity var(--dur) var(--ease);
}
.nav-toggle-bars i:nth-child(1) { top: 0; }
.nav-toggle-bars i:nth-child(2) { top: 5px; }
.nav-toggle-bars i:nth-child(3) { top: 10px; }

.site-header[data-open="true"] .nav-toggle-bars i:nth-child(1) { transform: translateY(5px) rotate(45deg); }
.site-header[data-open="true"] .nav-toggle-bars i:nth-child(2) { opacity: 0; }
.site-header[data-open="true"] .nav-toggle-bars i:nth-child(3) { transform: translateY(-5px) rotate(-45deg); }

/* 主导航 */
.primary-nav {
  display: flex;
  flex-direction: column;
  flex: 1 1 auto;
  min-height: 0;
  overflow-y: auto;
  padding: 18px 14px 20px;
}

.nav-list {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.nav-link {
  position: relative;
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding: 11px 12px;
  border: 2px solid transparent;
  color: var(--ink-2);
  transition: color var(--dur) var(--ease),
              background-color var(--dur) var(--ease),
              border-color var(--dur) var(--ease),
              transform var(--dur) var(--ease),
              box-shadow var(--dur) var(--ease);
}

.nav-idx {
  flex: none;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 11px;
  letter-spacing: .1em;
  color: var(--ink-3);
  transition: color var(--dur) var(--ease);
}

.nav-label {
  font-size: 15px;
  letter-spacing: .06em;
}

.nav-link:hover,
.nav-link:focus-visible {
  color: var(--ink);
  background: var(--panel-2);
  border-color: var(--line);
  box-shadow: var(--hard-sm);
  transform: translate(-2px, -2px);
}

.nav-link:hover .nav-idx { color: var(--winter); }

.nav-link[aria-current="page"] {
  color: var(--ink);
  background: linear-gradient(90deg, rgba(76,141,255,.16), rgba(76,141,255,0) 78%);
}

.nav-link[aria-current="page"]::before {
  content: "";
  position: absolute;
  left: -2px;
  top: -2px;
  bottom: -2px;
  width: 5px;
  background: var(--grad-seasons);
}

.nav-link[aria-current="page"] .nav-label { font-weight: 700; }
.nav-link[aria-current="page"] .nav-idx { color: var(--spring); }

/* 侧栏底部工具 */
.nav-tools {
  margin-top: auto;
  padding-top: 22px;
  display: flex;
  flex-direction: column;
  gap: 8px;
  border-top: 2px solid var(--line);
}

.nav-search {
  display: flex;
  align-items: center;
  gap: 10px;
  width: 100%;
  padding: 11px 12px;
  color: var(--ink-2);
  border: 2px solid var(--line);
  background: var(--panel-2);
  font-size: 13px;
  text-align: left;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.nav-search:hover { color: var(--ink); border-color: var(--winter); }

.nav-search-glyph {
  position: relative;
  display: block;
  width: 11px;
  height: 11px;
  flex: none;
  border: 2px solid currentColor;
  border-radius: 50%;
}

.nav-search-glyph::after {
  content: "";
  position: absolute;
  right: -5px;
  bottom: -3px;
  width: 6px;
  height: 2px;
  background: currentColor;
  transform: rotate(45deg);
}

.nav-search-text {
  overflow: hidden;
  white-space: nowrap;
  text-overflow: ellipsis;
}

.nav-cta {
  display: block;
  padding: 11px 12px;
  border: 2px solid var(--line);
  background: var(--panel-2);
  font-size: 13px;
  letter-spacing: .04em;
  text-align: center;
  transition: transform var(--dur) var(--ease),
              box-shadow var(--dur) var(--ease),
              border-color var(--dur) var(--ease),
              color var(--dur) var(--ease);
}

.nav-cta:hover {
  transform: translate(-2px, -2px);
  box-shadow: var(--hard-sm);
}

.nav-cta--strong {
  background: var(--grad-seasons);
  color: #05080F;
  font-weight: 700;
  border-color: transparent;
}

.nav-cta--strong:hover { border-color: var(--ink); }

.nav-cta--quiet { color: var(--ink-2); background: transparent; }
.nav-cta--quiet:hover { color: var(--ink); border-color: var(--winter); }

/* ---------- 8. 阅读进度条 ---------- */
.scroll-progress {
  position: fixed;
  top: 0;
  left: var(--rail-w);
  right: 0;
  height: 3px;
  z-index: 90;
  background: var(--grad-seasons);
  transform: scaleX(0);
  transform-origin: 0 50%;
  will-change: transform;
  pointer-events: none;
}

/* ---------- 9. 站内搜索浮层 ---------- */
.search-layer {
  position: fixed;
  inset: 0;
  z-index: 200;
  display: grid;
  justify-items: center;
  align-items: start;
  padding: 12vh 20px 24px;
  overflow-y: auto;
  background: rgba(4, 7, 14, .84);
  opacity: 0;
  visibility: hidden;
  transition: opacity 200ms var(--ease), visibility 200ms var(--ease);
}

.search-layer[data-open="true"] { opacity: 1; visibility: visible; }

.search-box {
  width: min(640px, 100%);
  padding: 20px;
  background: var(--panel);
  border: 2px solid var(--line);
  box-shadow: var(--hard);
}

.search-row {
  display: flex;
  gap: 10px;
  align-items: stretch;
}

.search-input {
  flex: 1 1 auto;
  min-width: 0;
  padding: 12px 14px;
  background: var(--bg);
  border: 2px solid var(--line);
  color: var(--ink);
  font-size: 15px;
}

.search-input::placeholder { color: var(--ink-3); }
.search-input:focus { border-color: var(--winter); outline: none; }
.search-input:focus-visible { outline: 3px solid var(--winter); outline-offset: 2px; }

.search-close {
  flex: none;
  padding: 12px 18px;
  border: 2px solid var(--line);
  color: var(--ink-2);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .18em;
  text-transform: uppercase;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.search-close:hover { color: var(--ink); border-color: var(--alert); }

.search-hint {
  margin-top: 14px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .14em;
  color: var(--ink-3);
  max-width: none;
}

.search-results {
  margin-top: 14px;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.search-result {
  display: block;
  width: 100%;
  padding: 11px 14px;
  text-align: left;
  border: 2px solid var(--line);
  background: var(--panel-2);
  color: var(--ink);
  font-size: 14px;
  transition: border-color var(--dur) var(--ease), transform var(--dur) var(--ease);
}

.search-result:hover { border-color: var(--spring); transform: translateX(3px); }

.search-result span {
  display: block;
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--ink-3);
}

/* ---------- 10. 页脚 ---------- */
.site-footer {
  position: relative;
  margin-top: 120px;
  background: var(--panel);
  border-top: 2px solid var(--line);
}

.site-footer::before {
  content: "";
  position: absolute;
  top: -3px;
  left: 0;
  right: 0;
  height: 3px;
  background: var(--grad-seasons);
}

.footer-inner {
  width: 100%;
  max-width: var(--shell-max);
  margin: 0 auto;
  padding: 68px 40px 28px;
}

.footer-top {
  display: grid;
  grid-template-columns: minmax(240px, 1fr) 2fr;
  gap: 56px;
  padding-bottom: 48px;
  border-bottom: 2px solid var(--line);
}

.footer-logo {
  display: inline-block;
  font-size: 26px;
  font-weight: 700;
  letter-spacing: .1em;
  color: var(--ink);
}

.footer-tag {
  margin-top: 8px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .18em;
  text-transform: uppercase;
  color: var(--autumn);
}

.footer-desc {
  margin-top: 16px;
  max-width: 34ch;
  font-size: 14px;
  color: var(--ink-2);
}

.footer-nav {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 32px;
}

.footer-col-title {
  margin-bottom: 16px;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 600;
  letter-spacing: .18em;
  text-transform: uppercase;
  color: var(--ink);
}

.footer-list {
  display: flex;
  flex-direction: column;
  gap: 9px;
}

.footer-list a {
  display: inline-block;
  font-size: 14px;
  color: var(--ink-2);
  transition: color var(--dur) var(--ease), transform var(--dur) var(--ease);
}

.footer-list a:hover { color: var(--winter); transform: translateX(3px); }

.footer-contact { padding: 40px 0; border-bottom: 2px solid var(--line); }

.contact-list {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(230px, 1fr));
  gap: 26px 40px;
}

.contact-item dt {
  margin-bottom: 7px;
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: .18em;
  text-transform: uppercase;
  color: var(--ink-3);
}

.contact-item dd {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  font-size: 14px;
  color: var(--ink);
  word-break: break-word;
}

.copy-btn {
  padding: 4px 10px;
  border: 2px solid var(--line);
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--ink-2);
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.copy-btn:hover { color: var(--spring); border-color: var(--spring); }
.copy-btn[data-copy-state="done"] { color: var(--spring); border-color: var(--spring); }
.copy-btn[data-copy-state="fail"] { color: var(--alert); border-color: var(--alert); }

.footer-bottom {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding-top: 24px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .12em;
  color: var(--ink-3);
}

.footer-copy,
.footer-icp { max-width: none; }

.footer-icp { color: var(--ink-2); }

/* ---------- 11. 通用组件 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 13px 22px;
  border: 2px solid var(--line);
  background: var(--panel-2);
  color: var(--ink);
  font-size: 14px;
  letter-spacing: .05em;
  transition: transform var(--dur) var(--ease),
              box-shadow var(--dur) var(--ease),
              border-color var(--dur) var(--ease),
              color var(--dur) var(--ease),
              background-color var(--dur) var(--ease);
}

.btn:hover,
.btn:focus-visible {
  transform: translate(-2px, -2px);
  box-shadow: var(--hard-sm);
}

.btn--primary {
  background: var(--grad-seasons);
  color: #05080F;
  font-weight: 700;
  border-color: transparent;
}

.btn--primary:hover { border-color: var(--ink); }

.btn--ghost { background: transparent; color: var(--ink-2); }
.btn--ghost:hover { color: var(--ink); border-color: var(--winter); }

.btn--winter { background: var(--winter); color: #04101F; border-color: transparent; font-weight: 700; }

.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 10px;
  border: 2px solid var(--line);
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--ink-2);
}

.tag--spring { color: var(--spring); border-color: var(--spring); }
.tag--summer { color: var(--summer); border-color: var(--summer); }
.tag--autumn { color: var(--autumn); border-color: var(--autumn); }
.tag--winter { color: var(--winter); border-color: var(--winter); }
.tag--alert { color: var(--alert); border-color: var(--alert); }

.panel {
  padding: 26px;
  background: var(--panel);
  border: 2px solid var(--line);
}

.card {
  position: relative;
  padding: 24px;
  background: var(--panel);
  border: 2px solid var(--line);
  transition: transform var(--dur) var(--ease),
              box-shadow var(--dur) var(--ease),
              border-color var(--dur) var(--ease);
}

.card--hard { box-shadow: var(--hard); }

.card:hover {
  transform: translate(-2px, -2px);
  box-shadow: var(--hard);
  border-color: var(--winter);
}

.card::before {
  content: "";
  position: absolute;
  top: -2px;
  left: -2px;
  width: 46px;
  height: 3px;
  background: var(--grad-seasons);
  opacity: 0;
  transition: opacity var(--dur) var(--ease);
}

.card:hover::before { opacity: 1; }

.table-scroll {
  overflow-x: auto;
  border: 2px solid var(--line);
  background: var(--panel);
}

.data-table {
  width: 100%;
  min-width: 520px;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 13px;
}

.data-table caption {
  padding: 14px 16px;
  text-align: left;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .18em;
  text-transform: uppercase;
  color: var(--ink-2);
  border-bottom: 2px solid var(--line);
}

.data-table th,
.data-table td {
  padding: 11px 16px;
  text-align: right;
  border-bottom: 1px solid var(--line);
}

.data-table th:first-child,
.data-table td:first-child { text-align: left; }

.data-table thead th {
  font-size: 10px;
  font-weight: 600;
  letter-spacing: .18em;
  text-transform: uppercase;
  color: var(--ink-2);
  background: var(--panel-2);
}

.data-table tbody tr:hover td { background: rgba(76, 141, 255, .07); }
.data-table tbody tr:last-child td { border-bottom: 0; }

.disclosure {
  border: 2px solid var(--line);
  background: var(--panel);
}

.disclosure + .disclosure { margin-top: -2px; }

.disclosure-trigger {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  width: 100%;
  padding: 18px 20px;
  text-align: left;
  font-size: 15px;
  font-weight: 500;
  color: var(--ink);
  transition: background-color var(--dur) var(--ease), color var(--dur) var(--ease);
}

.disclosure-trigger:hover { background: var(--panel-2); }

.disclosure-trigger::after {
  content: "+";
  flex: none;
  font-family: var(--font-mono);
  font-size: 18px;
  line-height: 1;
  color: var(--winter);
  transition: transform var(--dur) var(--ease), color var(--dur) var(--ease);
}

.disclosure-trigger[aria-expanded="true"]::after {
  content: "–";
  transform: rotate(0deg);
  color: var(--spring);
}

.disclosure-body {
  padding: 0 20px 20px;
  color: var(--ink-2);
  font-size: 14px;
}

.disclosure-body[hidden] { display: none; }

.quote {
  padding-left: 20px;
  border-left: 3px solid;
  border-image: var(--grad-seasons) 1;
  font-size: clamp(20px, 2.2vw, 24px);
  font-weight: 200;
  line-height: 1.5;
  color: var(--ink);
}

/* 图片容器 */
.media {
  position: relative;
  overflow: hidden;
  background: var(--panel-2);
  border: 2px solid var(--line);
  box-shadow: var(--hard);
}

.media > img,
.media > svg,
.media > .media-fill {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.media::after {
  content: "";
  position: absolute;
  inset: 0;
  background: var(--grad-glow);
  pointer-events: none;
}

.media--wide { aspect-ratio: 16 / 9; }
.media--tall { aspect-ratio: 3 / 4; }
.media--square { aspect-ratio: 1 / 1; }
.media--diagonal { clip-path: polygon(0 0, 100% 5%, 100% 100%, 0 95%); }

.media-caption {
  margin-top: 10px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .14em;
  color: var(--ink-3);
  max-width: none;
}

/* 动效协议 */
[data-reveal].is-entering {
  opacity: 0;
  transform: translateY(14px);
}

[data-reveal].is-entered {
  opacity: 1;
  transform: none;
  transition: opacity 420ms var(--ease), transform 420ms var(--ease);
}

/* 备用装饰线 */
.hairline {
  height: 1px;
  border: 0;
  border-top: 1px dashed var(--line);
}

/* ---------- 12. 响应式 ---------- */
@media (max-width: 1179px) and (min-width: 900px) {
  :root { --rail-w: 88px; }

  .rail-top { flex-direction: column; gap: 10px; padding: 18px 8px; }

  .brand { flex-direction: column; gap: 10px; }

  .brand-body { align-items: center; }

  .brand-name {
    writing-mode: vertical-rl;
    text-orientation: upright;
    letter-spacing: .18em;
    font-size: 15px;
  }

  .brand-tag { display: none; }

  .primary-nav { padding: 16px 8px 18px; }

  .nav-list { gap: 2px; align-items: center; }

  .nav-link {
    justify-content: center;
    padding: 12px 6px;
    gap: 6px;
  }

  .nav-idx { display: none; }

  .nav-label {
    writing-mode: vertical-rl;
    text-orientation: upright;
    letter-spacing: .18em;
    font-size: 13px;
  }

  .nav-tools { align-items: center; }

  .nav-search { justify-content: center; padding: 12px 6px; }
  .nav-search-text { display: none; }
  .nav-cta { display: none; }
}

@media (max-width: 899px) {
  body { padding-left: 0; padding-top: var(--topbar-h); }

  .site-header {
    flex-direction: row;
    align-items: stretch;
    top: 0;
    bottom: auto;
    width: 100%;
    height: var(--topbar-h);
    border-right: 0;
    border-bottom: 2px solid var(--line);
  }

  .rail-top {
    align-items: center;
    width: 100%;
    padding: 0 16px;
    border-bottom: 0;
  }

  .brand-tag { display: none; }
  .nav-toggle { display: inline-flex; }

  .primary-nav {
    position: fixed;
    top: var(--topbar-h);
    left: 0;
    right: 0;
    bottom: 0;
    padding: 22px 20px 32px;
    background: var(--panel);
    border-top: 2px solid var(--line);
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: opacity 220ms var(--ease),
                transform 220ms var(--ease),
                visibility 220ms var(--ease);
  }

  .site-header[data-open="true"] .primary-nav {
    opacity: 1;
    visibility: visible;
    transform: none;
  }

  .nav-link { padding: 15px 14px; }
  .nav-label { font-size: 17px; }

  .nav-tools { margin-top: 28px; padding-top: 22px; }
  .nav-search-text { white-space: normal; }

  .scroll-progress { left: 0; top: var(--topbar-h); }

  .shell { padding: 0 22px; }
  .page-head { padding: 52px 0 32px; }

  .site-footer { margin-top: 80px; }
  .footer-inner { padding: 48px 22px 24px; }
  .footer-top { grid-template-columns: 1fr; gap: 40px; padding-bottom: 36px; }
  .footer-nav { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 28px; }
  .footer-desc { max-width: 46ch; }
  .footer-bottom { flex-direction: column; align-items: flex-start; }
}

@media (max-width: 620px) {
  body { font-size: 15px; }

  .brand-name { font-size: 17px; }

  .shell { padding: 0 16px; }
  .page-head { padding: 40px 0 26px; }

  .display { font-size: clamp(36px, 11vw, 56px); }

  .footer-inner { padding: 40px 16px 22px; }
  .footer-nav { grid-template-columns: 1fr; gap: 24px; }
  .footer-logo { font-size: 22px; }

  .contact-list { grid-template-columns: 1fr; gap: 20px; }

  .search-layer { padding: 8vh 14px 20px; }
  .search-box { padding: 16px; }
  .search-row { flex-direction: column; }
  .search-close { width: 100%; }

  .data-table th,
  .data-table td { padding: 10px 12px; }

  .card, .panel { padding: 20px; }
}

/* ---------- 13. 减少动态 ---------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }

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

  .card:hover,
  .btn:hover,
  .nav-cta:hover,
  .nav-link:hover {
    transform: none;
    box-shadow: none;
  }

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