/* =========================================================
   聚合稳定入口 · 共享样式 /assets/site.css
   结构：reset → 变量 → 基础排版 → 布局工具 → 头部 → 页脚
        → 通用组件 → 响应式 → 动效偏好
   ========================================================= */

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

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

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

ul, ol { padding: 0; }

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

button {
  font: inherit;
  color: inherit;
  border: 0;
  background: none;
}

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

::selection {
  background: #18E0D0;
  color: #071A2B;
}

/* ---------- 2. CSS 变量 ---------- */
:root {
  --harbor: #071A2B;
  --abyss: #0C2B42;
  --cyan: #18E0D0;
  --mist: #8DFFF4;
  --amber: #FFB347;
  --amber-deep: #D97706;
  --fog: #EAF2F5;
  --paper: #F8FBFC;
  --ink: #15242E;
  --steel: #627785;
  --line: #C7D7DE;
  --success: #2DD4BF;

  --font-display: "Noto Sans SC", "Source Han Sans SC", "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;
  --font-body: "Noto Sans SC", "Source Han Sans SC", "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;
  --font-mono: "JetBrains Mono", "SFMono-Regular", Consolas, "Liberation Mono", monospace;

  --shell: 1320px;
  --gutter: clamp(18px, 4vw, 56px);
  --radius: 2px;
  --ease: cubic-bezier(.3, .7, .3, 1);
  --line-soft-dark: rgba(234, 242, 245, .12);
  --cyan-line: rgba(24, 224, 208, .22);
}

/* ---------- 3. 基础排版 ---------- */
body {
  min-height: 100%;
  font-family: var(--font-body);
  font-size: 16px;
  font-weight: 500;
  line-height: 1.7;
  color: var(--ink);
  background: var(--paper);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

h1, h2, h3, h4 {
  font-family: var(--font-display);
  font-weight: 700;
  line-height: 1.14;
  letter-spacing: -.02em;
}

h1 { font-size: clamp(34px, 5.4vw, 74px); }
h2 { font-size: clamp(24px, 3.2vw, 40px); }
h3 { font-size: clamp(17px, 1.8vw, 22px); letter-spacing: -.01em; }

p { text-wrap: pretty; }

:focus-visible {
  outline: 2px solid var(--amber-deep);
  outline-offset: 3px;
  border-radius: 1px;
}

.site-header :focus-visible,
.site-footer :focus-visible,
.section--dark :focus-visible {
  outline-color: var(--cyan);
}

main:focus { outline: none; }

.visually-hidden {
  position: absolute !important;
  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;
}

/* ---------- 4. 布局工具 ---------- */
.shell {
  width: 100%;
  max-width: var(--shell);
  margin: 0 auto;
  padding: 0 var(--gutter);
}

.section { padding: clamp(48px, 7vw, 96px) 0; }

.section--dark {
  background: var(--harbor);
  color: var(--paper);
}

.section--dark .eyebrow { color: var(--mist); }

.grid-12 {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  gap: clamp(16px, 2.4vw, 32px);
}

.stack {
  display: grid;
  gap: clamp(12px, 1.6vw, 20px);
}

.mono {
  font-family: var(--font-mono);
  font-size: .82em;
  letter-spacing: .12em;
  color: var(--steel);
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: .22em;
  text-transform: uppercase;
  color: var(--amber-deep);
}

.eyebrow::before {
  content: "";
  width: 20px;
  height: 1px;
  background: currentColor;
  flex: none;
}

.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 10px;
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: .14em;
  color: var(--abyss);
  background: rgba(24, 224, 208, .12);
  border: 1px solid rgba(24, 224, 208, .42);
  border-radius: var(--radius);
}

.section--dark .tag {
  color: var(--mist);
  background: rgba(24, 224, 208, .1);
  border-color: rgba(24, 224, 208, .38);
}

/* ---------- 5. Skip link ---------- */
.skip-link {
  position: fixed;
  top: 10px;
  left: 10px;
  z-index: 200;
  padding: 11px 20px;
  font-size: 14px;
  font-weight: 700;
  letter-spacing: .04em;
  color: #1A1206;
  background: var(--amber);
  border-radius: var(--radius);
  transform: translateY(-220%);
  transition: transform .16s var(--ease);
}

.skip-link:focus,
.skip-link:focus-visible { transform: translateY(0); }

/* ---------- 6. 头部 ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 60;
  color: var(--paper);
  background: var(--harbor);
  border-bottom: 1px solid var(--cyan-line);
  isolation: isolate;
  transition: box-shadow .2s var(--ease);
}

.site-header::after {
  content: "";
  position: absolute;
  right: 0;
  bottom: -1px;
  width: min(38vw, 420px);
  height: 2px;
  background: linear-gradient(90deg, rgba(24, 224, 208, 0), var(--cyan));
  opacity: .85;
  pointer-events: none;
}

.site-header[data-scrolled] {
  box-shadow: 0 22px 44px -28px rgba(3, 12, 20, .95);
}

.site-header[data-scrolled] .header-utility { opacity: .88; }

.header-inner {
  width: 100%;
  max-width: var(--shell);
  margin: 0 auto;
  padding: 0 var(--gutter);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: clamp(14px, 3vw, 40px);
}

/* 上层：品牌 + 辅助通道 */
.header-utility {
  background: var(--harbor);
  border-bottom: 1px solid rgba(234, 242, 245, .07);
  transition: opacity .2s var(--ease);
}

.header-utility .header-inner { min-height: 48px; }

.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  min-width: 0;
  padding: 6px 0;
  color: inherit;
}

.brand-node {
  flex: none;
  width: 13px;
  height: 13px;
  background: var(--cyan);
  box-shadow: 0 0 0 1px rgba(24, 224, 208, .35), 0 0 18px rgba(24, 224, 208, .5);
  transform: rotate(45deg);
  transition: transform .22s var(--ease), box-shadow .22s var(--ease);
}

.brand:hover .brand-node,
.brand:focus-visible .brand-node {
  transform: rotate(135deg);
  box-shadow: 0 0 0 1px rgba(255, 179, 71, .6), 0 0 20px rgba(24, 224, 208, .6);
}

.brand-text {
  display: flex;
  flex-direction: column;
  min-width: 0;
  line-height: 1.2;
}

.brand-name {
  font-family: var(--font-display);
  font-size: 15px;
  font-weight: 700;
  letter-spacing: .07em;
  color: var(--paper);
  white-space: nowrap;
}

.brand-tagline {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: .2em;
  color: rgba(141, 255, 244, .72);
  white-space: nowrap;
}

.utility-nav ul {
  display: flex;
  align-items: center;
  gap: clamp(12px, 2vw, 28px);
  list-style: none;
  margin: 0;
  padding: 0;
}

.utility-nav a {
  position: relative;
  display: inline-block;
  padding: 2px 0;
  font-size: 12.5px;
  font-weight: 500;
  letter-spacing: .08em;
  color: rgba(234, 242, 245, .7);
  white-space: nowrap;
  transition: color .16s var(--ease);
}

.utility-nav a::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: -3px;
  height: 1px;
  background: var(--cyan);
  transform: scaleX(0);
  transform-origin: 0 50%;
  transition: transform .2s var(--ease);
}

.utility-nav a:hover,
.utility-nav a:focus-visible { color: var(--mist); }

.utility-nav a:hover::after,
.utility-nav a:focus-visible::after { transform: scaleX(1); }

.utility-nav a[aria-current="page"] { color: var(--paper); }

.utility-nav a[aria-current="page"]::after {
  transform: scaleX(1);
  background: var(--amber);
}

/* 下层：主栏目 + 行动点 + 移动开关 */
.header-primary {
  background: linear-gradient(180deg, rgba(12, 43, 66, .96), rgba(7, 26, 43, .97));
  -webkit-backdrop-filter: blur(10px);
  backdrop-filter: blur(10px);
  border-top: 1px solid rgba(234, 242, 245, .05);
}

.header-primary .header-inner { min-height: 64px; }

.primary-nav { min-width: 0; }

.nav-list {
  display: flex;
  align-items: center;
  gap: clamp(2px, .8vw, 8px);
  list-style: none;
  margin: 0;
  padding: 0;
}

.nav-link {
  position: relative;
  display: inline-flex;
  align-items: baseline;
  gap: 8px;
  padding: 10px 12px;
  font-size: 14.5px;
  font-weight: 600;
  letter-spacing: .04em;
  color: rgba(234, 242, 245, .76);
  transition: color .16s var(--ease), background-color .16s var(--ease);
}

.nav-index {
  font-family: var(--font-mono);
  font-size: 10px;
  font-weight: 500;
  letter-spacing: .1em;
  color: rgba(141, 255, 244, .45);
  transition: color .16s var(--ease);
}

.nav-link::after {
  content: "";
  position: absolute;
  left: 12px;
  right: 12px;
  bottom: 6px;
  height: 2px;
  background: var(--cyan);
  transform: scaleX(0);
  transform-origin: 0 50%;
  transition: transform .2s var(--ease);
}

.nav-link:hover,
.nav-link:focus-visible {
  color: var(--paper);
  background: rgba(24, 224, 208, .07);
}

.nav-link:hover .nav-index,
.nav-link:focus-visible .nav-index { color: var(--mist); }

.nav-link:hover::after,
.nav-link:focus-visible::after { transform: scaleX(1); }

.nav-link[aria-current="page"] { color: var(--paper); }

.nav-link[aria-current="page"] .nav-index { color: var(--amber); }

.nav-link[aria-current="page"]::after { transform: scaleX(1); }

.nav-link[aria-current="page"]::before {
  content: "";
  position: absolute;
  left: 3px;
  top: 50%;
  width: 5px;
  height: 5px;
  margin-top: -2.5px;
  background: var(--amber);
  transform: rotate(45deg);
}

.header-cta {
  position: relative;
  flex: none;
  display: inline-flex;
  align-items: center;
  gap: 10px;
  margin-left: auto;
  padding: 11px 22px;
  font-size: 14px;
  font-weight: 700;
  letter-spacing: .05em;
  color: #1A1206;
  background: var(--amber);
  border-radius: 1px;
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 11px), calc(100% - 11px) 100%, 0 100%);
  transition: background-color .18s var(--ease), transform .18s var(--ease);
}

.header-cta::after {
  content: "→";
  font-family: var(--font-mono);
  font-size: 13px;
  line-height: 1;
  transition: transform .18s var(--ease);
}

.header-cta:hover,
.header-cta:focus-visible { background: var(--amber-deep); }

.header-cta:hover { transform: translateY(-2px); }

.header-cta:hover::after,
.header-cta:focus-visible::after { transform: translateX(3px); }

.nav-toggle {
  display: none;
  align-items: center;
  gap: 10px;
  padding: 9px 14px;
  color: var(--paper);
  background: transparent;
  border: 1px solid rgba(24, 224, 208, .45);
  border-radius: var(--radius);
  cursor: pointer;
  transition: border-color .16s var(--ease), background-color .16s var(--ease);
}

.nav-toggle:hover { background: rgba(24, 224, 208, .1); }

.nav-toggle-bars {
  position: relative;
  display: block;
  width: 18px;
  height: 2px;
  background: var(--cyan);
  transition: background-color .18s var(--ease);
}

.nav-toggle-bars::before,
.nav-toggle-bars::after {
  content: "";
  position: absolute;
  left: 0;
  width: 18px;
  height: 2px;
  background: var(--cyan);
  transition: transform .18s var(--ease);
}

.nav-toggle-bars::before { top: -6px; }
.nav-toggle-bars::after { top: 6px; }

.nav-toggle-label {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .14em;
}

.site-header[data-open] .nav-toggle-bars { background: transparent; }

.site-header[data-open] .nav-toggle-bars::before { transform: translateY(6px) rotate(45deg); }

.site-header[data-open] .nav-toggle-bars::after { transform: translateY(-6px) rotate(-45deg); }

/* 滚动进度发丝条 */
.header-progress {
  position: absolute;
  left: 0;
  right: 0;
  bottom: -1px;
  height: 2px;
  z-index: 2;
  pointer-events: none;
}

.header-progress::after {
  content: "";
  display: block;
  height: 100%;
  width: 100%;
  transform: scaleX(var(--progress, 0));
  transform-origin: 0 50%;
  background: linear-gradient(90deg, var(--cyan), var(--mist) 55%, var(--amber));
  transition: transform .1s linear;
}

/* ---------- 7. 页脚 ---------- */
.site-footer {
  position: relative;
  margin-top: clamp(56px, 9vw, 132px);
  padding: clamp(44px, 6.5vw, 88px) 0 clamp(22px, 3vw, 34px);
  color: var(--paper);
  background-color: var(--harbor);
  background-image:
    repeating-linear-gradient(90deg, rgba(141, 255, 244, .055) 0 1px, transparent 1px 96px),
    radial-gradient(120% 90% at 100% 0%, rgba(24, 224, 208, .16), rgba(7, 26, 43, 0) 62%),
    radial-gradient(80% 70% at 0% 100%, rgba(255, 179, 71, .07), rgba(7, 26, 43, 0) 60%);
  border-top: 1px solid var(--cyan-line);
}

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

.footer-top {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  gap: clamp(28px, 4vw, 48px) clamp(20px, 3vw, 44px);
}

.footer-brand {
  grid-column: span 5;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.footer-eyebrow {
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: .24em;
  color: rgba(141, 255, 244, .6);
}

.footer-brand .brand { padding: 0; }

.footer-brand .brand-name { font-size: 17px; letter-spacing: .08em; }

.footer-statement {
  max-width: 20ch;
  font-family: var(--font-display);
  font-size: clamp(21px, 2.5vw, 32px);
  font-weight: 700;
  line-height: 1.36;
  letter-spacing: -.01em;
  color: var(--paper);
}

.footer-nav {
  grid-column: span 4;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: clamp(16px, 2vw, 28px);
}

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

.footer-group-title {
  margin-bottom: 14px;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: .2em;
  color: rgba(141, 255, 244, .72);
}

.footer-links {
  display: grid;
  gap: 9px;
  list-style: none;
  margin: 0;
  padding: 0;
}

.footer-links a {
  position: relative;
  display: inline-block;
  padding-bottom: 2px;
  font-size: 14px;
  color: rgba(234, 242, 245, .74);
  transition: color .16s var(--ease);
}

.footer-links a::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 1px;
  background: var(--cyan);
  transform: scaleX(0);
  transform-origin: 0 50%;
  transition: transform .2s var(--ease);
}

.footer-links a:hover,
.footer-links a:focus-visible { color: var(--paper); }

.footer-links a:hover::after,
.footer-links a:focus-visible::after { transform: scaleX(1); }

.footer-contact {
  grid-column: span 3;
  min-width: 0;
}

.contact-list {
  display: grid;
  gap: 10px;
  list-style: none;
  margin: 0;
  padding: 0;
}

.contact-row {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 8px;
  padding-bottom: 9px;
  border-bottom: 1px dashed rgba(234, 242, 245, .14);
}

.contact-label {
  flex: none;
  min-width: 38px;
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: .16em;
  color: rgba(141, 255, 244, .6);
}

.contact-value {
  flex: 1 1 auto;
  min-width: 0;
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: .01em;
  color: var(--paper);
  word-break: break-all;
}

.contact-value--plain { font-family: var(--font-body); font-size: 13px; }

.copy-btn {
  flex: none;
  padding: 3px 9px;
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: .12em;
  color: rgba(141, 255, 244, .82);
  background: transparent;
  border: 1px solid rgba(24, 224, 208, .34);
  border-radius: var(--radius);
  cursor: pointer;
  transition: color .16s var(--ease), border-color .16s var(--ease), background-color .16s var(--ease);
}

.copy-btn:hover,
.copy-btn:focus-visible {
  color: var(--harbor);
  background: var(--cyan);
  border-color: var(--cyan);
}

.copy-btn[data-copied] {
  color: var(--harbor);
  background: var(--success);
  border-color: var(--success);
}

.footer-note {
  margin-top: 14px;
  font-size: 12px;
  line-height: 1.65;
  color: rgba(234, 242, 245, .55);
}

.footer-bottom {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 10px 28px;
  margin-top: clamp(30px, 5vw, 60px);
  padding-top: 18px;
  border-top: 1px solid rgba(234, 242, 245, .1);
}

.footer-legal {
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .02em;
  color: rgba(234, 242, 245, .55);
}

.footer-meta {
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: .16em;
  color: rgba(141, 255, 244, .55);
}

/* ---------- 8. 通用组件 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 13px 24px;
  font-family: var(--font-body);
  font-size: 14px;
  font-weight: 700;
  letter-spacing: .05em;
  color: var(--paper);
  background: var(--abyss);
  border: 1px solid transparent;
  border-radius: var(--radius);
  cursor: pointer;
  transition: background-color .18s var(--ease), color .18s var(--ease),
              border-color .18s var(--ease), transform .18s var(--ease);
}

.btn:hover { transform: translateY(-2px); }

.btn--amber { background: var(--amber); color: #1A1206; }

.btn--amber:hover { background: var(--amber-deep); }

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

.btn--ghost:hover {
  color: var(--abyss);
  border-color: var(--cyan);
  background: rgba(24, 224, 208, .08);
}

.section--dark .btn--ghost {
  color: var(--paper);
  border-color: rgba(141, 255, 244, .38);
}

.section--dark .btn--ghost:hover {
  color: var(--harbor);
  background: var(--mist);
  border-color: var(--mist);
}

.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  list-style: none;
  margin: 0;
  padding: 0;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .1em;
  color: var(--steel);
}

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

.breadcrumb li + li::before {
  content: "/";
  margin-right: 8px;
  color: var(--line);
}

.breadcrumb a {
  border-bottom: 1px solid transparent;
  transition: color .16s var(--ease), border-color .16s var(--ease);
}

.breadcrumb a:hover,
.breadcrumb a:focus-visible {
  color: var(--abyss);
  border-bottom-color: var(--cyan);
}

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

.prose {
  max-width: 38em;
  font-size: clamp(15px, 1.05vw, 17px);
  line-height: 1.85;
  color: var(--ink);
}

.prose > * + * { margin-top: 1.1em; }

.prose h2 {
  margin-top: 2em;
  font-size: clamp(21px, 2.2vw, 30px);
  letter-spacing: -.01em;
}

.prose h3 {
  margin-top: 1.8em;
  font-size: clamp(17px, 1.6vw, 21px);
}

.prose ul,
.prose ol {
  padding-left: 1.25em;
  display: grid;
  gap: .45em;
}

.prose a {
  color: var(--abyss);
  border-bottom: 1px solid var(--cyan);
  transition: color .16s var(--ease), border-color .16s var(--ease);
}

.prose a:hover,
.prose a:focus-visible {
  color: var(--amber-deep);
  border-bottom-color: var(--amber-deep);
}

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

.prose blockquote {
  padding: 4px 0 4px 18px;
  border-left: 2px solid var(--cyan);
  color: var(--steel);
}

.panel {
  padding: clamp(20px, 3vw, 34px);
  color: var(--paper);
  background: var(--abyss);
  border: 1px solid rgba(24, 224, 208, .18);
  border-radius: var(--radius);
}

.panel--paper {
  color: var(--ink);
  background: var(--paper);
  border-color: var(--line);
}

.panel--glass {
  color: var(--paper);
  background: rgba(234, 242, 245, .06);
  border: 1px solid rgba(141, 255, 244, .22);
  -webkit-backdrop-filter: blur(8px);
  backdrop-filter: blur(8px);
}

/* 可复用图片容器：页面阶段放占位图 */
.media-frame {
  position: relative;
  isolation: isolate;
  overflow: hidden;
  width: 100%;
  background: linear-gradient(140deg, var(--abyss), var(--harbor));
  border: 1px solid rgba(24, 224, 208, .2);
  border-radius: var(--radius);
}

.media-frame::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  opacity: .45;
  background-image:
    repeating-linear-gradient(90deg, rgba(24, 224, 208, .14) 0 1px, transparent 1px 34px),
    repeating-linear-gradient(0deg, rgba(24, 224, 208, .1) 0 1px, transparent 1px 34px);
}

.media-frame img,
.media-frame picture,
.media-frame video,
.media-frame svg {
  position: relative;
  z-index: 1;
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.media-frame--wide { aspect-ratio: 16 / 9; }
.media-frame--square { aspect-ratio: 1 / 1; }
.media-frame--tall { aspect-ratio: 3 / 4; }
.media-frame--band { aspect-ratio: 21 / 9; }

/* 前端切换（大屏预览 / 导出格式对比等） */
.tabbar {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin: 0 0 22px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--line);
}

.tabbar-btn {
  padding: 9px 16px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .1em;
  color: var(--steel);
  background: transparent;
  border: 1px solid transparent;
  border-radius: var(--radius);
  cursor: pointer;
  transition: color .16s var(--ease), background-color .16s var(--ease), border-color .16s var(--ease);
}

.tabbar-btn:hover {
  color: var(--abyss);
  border-color: var(--line);
}

.tabbar-btn[aria-selected="true"] {
  color: var(--paper);
  background: var(--abyss);
  border-color: var(--abyss);
}

.section--dark .tabbar { border-bottom-color: rgba(234, 242, 245, .16); }

.section--dark .tabbar-btn { color: rgba(234, 242, 245, .6); }

.section--dark .tabbar-btn:hover { color: var(--paper); border-color: rgba(141, 255, 244, .4); }

.section--dark .tabbar-btn[aria-selected="true"] {
  color: var(--harbor);
  background: var(--cyan);
  border-color: var(--cyan);
}

[data-tab-panel][hidden] { display: none; }

[data-tab-panel].is-active { display: block; }

/* 显现 */
[data-reveal] { opacity: 1; transform: none; }

html.reveal-ready [data-reveal] {
  opacity: 0;
  transform: translateY(14px);
  transition: opacity .5s var(--ease), transform .5s var(--ease);
}

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

/* ---------- 9. 响应式 ---------- */
@media (max-width: 1080px) {
  .footer-brand { grid-column: span 12; }
  .footer-nav { grid-column: span 7; }
  .footer-contact { grid-column: span 5; }
  .footer-statement { max-width: 26ch; }
}

@media (max-width: 900px) {
  .nav-toggle { display: inline-flex; }

  .header-utility .header-inner { min-height: 44px; gap: 12px; }
  .header-primary .header-inner { min-height: 58px; }

  .header-cta { margin-left: 0; margin-right: auto; }

  .primary-nav {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    max-height: 0;
    overflow: hidden;
    padding: 0 var(--gutter);
    visibility: hidden;
    opacity: 0;
    pointer-events: none;
    transform: translateY(-6px);
    background: var(--harbor);
    border-bottom: 1px solid rgba(24, 224, 208, .3);
    box-shadow: 0 26px 50px -30px #000;
    transition: max-height .22s var(--ease), opacity .18s var(--ease),
                transform .22s var(--ease), visibility .18s linear, padding .22s var(--ease);
  }

  .site-header[data-open] .primary-nav {
    max-height: 72vh;
    overflow-y: auto;
    visibility: visible;
    opacity: 1;
    pointer-events: auto;
    transform: none;
    padding-top: 6px;
    padding-bottom: 18px;
  }

  .nav-list {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
  }

  .nav-link {
    width: 100%;
    justify-content: flex-start;
    padding: 15px 8px;
    font-size: 16px;
    border-bottom: 1px solid rgba(234, 242, 245, .08);
  }

  .nav-link::after { display: none; }

  .nav-link[aria-current="page"] {
    padding-left: 18px;
    background: rgba(24, 224, 208, .08);
  }

  .nav-link[aria-current="page"]::before {
    left: 8px;
    margin-top: -2.5px;
  }

  .footer-nav { grid-column: span 12; }
  .footer-contact { grid-column: span 12; }
}

@media (max-width: 640px) {
  .header-utility .header-inner { align-items: center; }

  .brand { gap: 9px; }

  .brand-name { font-size: 13.5px; letter-spacing: .04em; }

  .utility-nav { min-width: 0; }

  .utility-nav ul {
    gap: 12px;
    overflow-x: auto;
    scrollbar-width: none;
  }

  .utility-nav ul::-webkit-scrollbar { display: none; }

  .utility-nav a { font-size: 11.5px; letter-spacing: .02em; }

  .header-cta { padding: 9px 13px; font-size: 12.5px; }

  .header-cta::after { display: none; }

  .nav-toggle { padding: 8px 11px; }

  .footer-top { gap: 30px; }

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

  .footer-statement { max-width: none; font-size: 22px; }

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

  .media-frame--band { aspect-ratio: 16 / 9; }
}

@media (max-width: 380px) {
  .brand-tagline { display: none; }
}

/* ---------- 10. 动效偏好 ---------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }

  *,
  *::before,
  *::after {
    animation-duration: .001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .001ms !important;
    transition-delay: 0ms !important;
  }

  html.reveal-ready [data-reveal] {
    opacity: 1;
    transform: none;
  }

  .header-progress::after { transition: none; }

  .btn:hover,
  .header-cta:hover { transform: none; }
}