/* ==========================================================================
   im钱包下载中心 — 共享样式 /assets/site.css
   结构：reset → 变量 → 基础排版 → 布局容器 → 页头 → 页脚 → 通用组件 → 图片容器 → 响应式 → 动效
   ========================================================================== */

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

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--nav-h) + 24px);
}

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

ul, ol { padding: 0; list-style: none; }

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

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

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

a { color: inherit; }

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

/* ---------- 变量 ---------- */
:root {
  --ink-950: #070F1C;
  --ink-900: #0B1526;
  --ink-800: #121F35;
  --ink-700: #1B2C48;
  --hairline: #2C3E5E;

  --teal: #2ED3A6;
  --teal-deep: #12866A;
  --amber: #FFB44D;
  --amber-deep: #B9720F;
  --violet-legacy: #6C6A88;

  --paper: #F1EFE8;
  --text-hi: #E9EEF6;
  --text-mid: #9DAAC0;
  --text-on-paper: #14213A;

  --teal-a08: rgba(46, 211, 166, 0.08);
  --teal-a16: rgba(46, 211, 166, 0.16);
  --teal-a32: rgba(46, 211, 166, 0.32);
  --teal-a56: rgba(46, 211, 166, 0.56);
  --amber-a08: rgba(255, 180, 77, 0.08);
  --amber-a28: rgba(255, 180, 77, 0.28);
  --amber-a48: rgba(255, 180, 77, 0.48);
  --violet-a28: rgba(108, 106, 136, 0.28);
  --violet-a50: rgba(108, 106, 136, 0.50);
  --paper-a06: rgba(241, 239, 232, 0.06);
  --paper-a10: rgba(241, 239, 232, 0.10);

  --font-display: "Inter Tight", "Inter", "Noto Sans SC", "Source Han Sans SC",
    system-ui, -apple-system, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --font-body: "Inter", "Noto Sans SC", "Source Han Sans SC",
    system-ui, -apple-system, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --font-mono: "JetBrains Mono", "IBM Plex Mono", SFMono-Regular, Menlo, Consolas,
    "Liberation Mono", monospace;

  --shell: 1280px;
  --gutter: clamp(18px, 4vw, 40px);
  --nav-h: 68px;

  --ease: cubic-bezier(0.2, 0.7, 0.2, 1);
  --dur: 180ms;
  --dur-slow: 220ms;

  --shadow-hover: 0 18px 40px -28px rgba(0, 0, 0, 0.92);
}

/* ---------- 基础排版 ---------- */
body {
  padding-top: var(--nav-h);
  background-color: var(--ink-900);
  color: var(--text-hi);
  font-family: var(--font-body);
  font-size: 16.5px;
  line-height: 1.75;
  font-weight: 400;
  letter-spacing: 0.005em;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
}

h1, h2, h3, h4 {
  font-family: var(--font-display);
  font-weight: 250;
  line-height: 1.12;
  letter-spacing: -0.018em;
  color: var(--text-hi);
}

h1 { font-size: clamp(34px, 5.4vw, 76px); line-height: 1.04; }
h2 { font-size: clamp(26px, 3.4vw, 46px); }
h3 { font-size: clamp(19px, 2vw, 26px); font-weight: 300; }
h4 { font-size: 17px; font-weight: 450; letter-spacing: 0.005em; }

p { color: var(--text-mid); }

strong, b { color: var(--text-hi); font-weight: 550; }

::selection {
  background: var(--teal-a32);
  color: var(--text-hi);
}

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

hr {
  border: 0;
  border-top: 1px solid var(--hairline);
  margin: 0;
}

/* ---------- 布局容器 ---------- */
.shell {
  width: 100%;
  max-width: var(--shell);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.grid-12 {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  gap: 24px;
}

.grid-12 > .col-3 { grid-column: span 3; }
.grid-12 > .col-4 { grid-column: span 4; }
.grid-12 > .col-5 { grid-column: span 5; }
.grid-12 > .col-6 { grid-column: span 6; }
.grid-12 > .col-7 { grid-column: span 7; }
.grid-12 > .col-8 { grid-column: span 8; }
.grid-12 > .col-12 { grid-column: span 12; }

.section {
  padding-block: clamp(56px, 8vw, 104px);
  border-top: 1px solid var(--hairline);
}

.section--plain { border-top: 0; }

.section--deep {
  background-color: var(--ink-950);
}

.section--panel {
  background-color: var(--ink-800);
}

.hero--overlay {
  margin-top: calc(-1 * var(--nav-h));
  padding-top: calc(var(--nav-h) + clamp(40px, 6vw, 88px));
}

/* ---------- 跳过链接 ---------- */
.skip-link {
  position: fixed;
  top: 10px;
  left: 10px;
  z-index: 200;
  padding: 10px 16px;
  background-color: var(--ink-800);
  color: var(--text-hi);
  border: 1px solid var(--teal);
  border-radius: 2px;
  font-size: 13px;
  letter-spacing: 0.04em;
  text-decoration: none;
  transform: translateY(-160%);
  transition: transform var(--dur) var(--ease);
}

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

/* ---------- 页头 ---------- */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 80;
  background-color: transparent;
  border-bottom: 1px solid transparent;
  transition: background-color var(--dur-slow) var(--ease),
              border-color var(--dur-slow) var(--ease);
}

.site-header[data-scrolled="true"],
.site-header[data-open] {
  background-color: var(--ink-900);
  border-bottom-color: var(--hairline);
}

.site-header__inner {
  position: relative;
  display: flex;
  align-items: center;
  gap: clamp(14px, 2vw, 30px);
  width: 100%;
  max-width: var(--shell);
  margin-inline: auto;
  padding-inline: var(--gutter);
  height: var(--nav-h);
  transition: height var(--dur-slow) var(--ease);
}

.site-header[data-scrolled="true"] .site-header__inner {
  height: 58px;
}

/* 品牌 */
.brand {
  display: inline-flex;
  align-items: center;
  gap: 11px;
  flex: 0 0 auto;
  text-decoration: none;
  color: var(--text-hi);
}

.brand__mark {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 34px;
  height: 26px;
  padding: 0 7px;
  font-family: var(--font-mono);
  font-size: 12.5px;
  font-weight: 500;
  letter-spacing: 0.06em;
  line-height: 1;
  color: var(--teal);
  background-color: var(--teal-a08);
  border: 1px solid var(--teal-a32);
  border-radius: 2px;
  transition: background-color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.brand:hover .brand__mark,
.brand:focus-visible .brand__mark {
  background-color: var(--teal-a16);
  border-color: var(--teal);
}

.brand__text {
  display: flex;
  flex-direction: column;
  gap: 1px;
  min-width: 0;
}

.brand__name {
  font-family: var(--font-display);
  font-size: 15.5px;
  font-weight: 450;
  letter-spacing: 0.01em;
  line-height: 1.2;
  white-space: nowrap;
}

.brand__tag {
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: 0.14em;
  color: var(--text-mid);
  line-height: 1.2;
  white-space: nowrap;
}

/* 导航 */
.nav {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: clamp(14px, 2vw, 32px);
  flex: 1 1 auto;
  margin-left: auto;
}

.nav__list {
  display: flex;
  align-items: center;
  gap: clamp(12px, 1.7vw, 28px);
}

.nav__item { position: relative; }

.nav__link {
  position: relative;
  display: inline-block;
  padding: 6px 1px;
  font-size: 13.5px;
  letter-spacing: 0.02em;
  color: var(--text-mid);
  text-decoration: none;
  white-space: nowrap;
  transition: color var(--dur) var(--ease), opacity var(--dur) var(--ease);
}

.nav__link::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 1px;
  background-color: var(--teal);
  transform: scaleX(0);
  transform-origin: left center;
  transition: transform var(--dur) var(--ease);
}

.nav__link:hover,
.nav__link:focus-visible {
  color: var(--text-hi);
}

.nav__link:hover::after,
.nav__link:focus-visible::after,
.nav__link[aria-current="page"]::after {
  transform: scaleX(1);
}

.nav__link[aria-current="page"] {
  color: var(--text-hi);
}

.nav:hover .nav__link:not(:hover):not([aria-current="page"]) {
  opacity: 0.7;
}

/* 页头工具入口 */
.nav__tools {
  display: flex;
  align-items: center;
  gap: 10px;
}

.utility-link {
  display: inline-flex;
  align-items: center;
  padding: 7px 11px;
  font-size: 12px;
  letter-spacing: 0.05em;
  line-height: 1.2;
  color: var(--text-hi);
  text-decoration: none;
  border: 1px solid var(--hairline);
  border-radius: 2px;
  white-space: nowrap;
  transition: border-color var(--dur) var(--ease), color var(--dur) var(--ease),
              background-color var(--dur) var(--ease);
}

.utility-link:hover,
.utility-link:focus-visible {
  border-color: var(--teal-a56);
  color: var(--teal);
  background-color: var(--teal-a08);
}

.utility-link--legacy {
  color: var(--violet-legacy);
  border-color: var(--violet-a28);
}

.utility-link--legacy:hover,
.utility-link--legacy:focus-visible {
  color: var(--violet-legacy);
  border-color: var(--violet-a50);
  background-color: var(--paper-a06);
}

/* 移动导航按钮 */
.nav-toggle {
  display: none;
  align-items: center;
  gap: 9px;
  padding: 8px 11px;
  color: var(--text-hi);
  border: 1px solid var(--hairline);
  border-radius: 2px;
  transition: border-color var(--dur) var(--ease), background-color var(--dur) var(--ease);
}

.nav-toggle:hover,
.nav-toggle:focus-visible {
  border-color: var(--teal-a56);
  background-color: var(--teal-a08);
}

.nav-toggle__bars {
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  width: 16px;
  height: 10px;
}

.nav-toggle__bar {
  display: block;
  width: 100%;
  height: 1px;
  background-color: currentColor;
  transition: transform var(--dur) var(--ease), opacity var(--dur) var(--ease);
}

.nav-toggle__label {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
}

.nav-toggle[aria-expanded="true"] .nav-toggle__bar:first-child {
  transform: translateY(4.5px) rotate(45deg);
}

.nav-toggle[aria-expanded="true"] .nav-toggle__bar:last-child {
  transform: translateY(-4.5px) rotate(-45deg);
}

/* 滚动进度 */
.scroll-progress {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 1px;
  background-color: transparent;
  pointer-events: none;
}

.scroll-progress::after {
  content: "";
  position: absolute;
  inset: 0 auto 0 0;
  width: 100%;
  background-image: linear-gradient(90deg, var(--teal), var(--amber));
  transform: scaleX(var(--progress, 0));
  transform-origin: left center;
  transition: transform 90ms linear;
}

/* ---------- 页脚 ---------- */
.site-footer {
  background-color: var(--ink-950);
  border-top: 1px solid var(--hairline);
  color: var(--text-mid);
  font-size: 14px;
  padding-top: clamp(44px, 6vw, 80px);
}

.footer-inner {
  width: 100%;
  max-width: var(--shell);
  margin-inline: auto;
  padding-inline: var(--gutter);
  padding-bottom: 34px;
}

.footer-lead {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  padding-bottom: 28px;
  border-bottom: 1px solid var(--hairline);
}

.brand--footer .brand__tag { color: var(--violet-legacy); }

.footer-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: clamp(22px, 3vw, 48px);
  padding-block: clamp(30px, 4vw, 52px);
}

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

.footer-col__title {
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 400;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--text-mid);
  margin-bottom: 15px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--hairline);
}

.footer-links {
  display: grid;
  gap: 11px;
}

.footer-links a {
  display: inline-block;
  font-size: 13.5px;
  line-height: 1.5;
  color: var(--text-hi);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color var(--dur) var(--ease), color var(--dur) var(--ease);
}

.footer-links a:hover,
.footer-links a:focus-visible {
  color: #ffffff;
  border-bottom-color: var(--teal);
}

.footer-links em {
  display: block;
  margin-top: 3px;
  font-style: normal;
  font-size: 12px;
  line-height: 1.5;
  color: var(--text-mid);
}

.footer-info {
  display: grid;
  gap: 10px;
  font-size: 12.5px;
  line-height: 1.65;
}

.footer-info .mono {
  font-size: 12px;
}

.footer-base {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: 14px;
  padding-top: 22px;
  border-top: 1px solid var(--hairline);
}

.footer-reminder {
  flex: 1 1 420px;
  max-width: 62ch;
  font-size: 12.5px;
  line-height: 1.7;
  color: var(--violet-legacy);
}

.footer-legal {
  flex: 0 0 auto;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.08em;
  color: var(--text-mid);
}

/* ---------- 通用按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  min-height: 42px;
  padding: 0 18px;
  font-family: var(--font-body);
  font-size: 13.5px;
  letter-spacing: 0.03em;
  line-height: 1.2;
  color: var(--text-hi);
  text-decoration: none;
  background-color: transparent;
  border: 1px solid var(--hairline);
  border-radius: 2px;
  transition: background-color var(--dur) var(--ease), border-color var(--dur) var(--ease),
              color var(--dur) var(--ease);
}

.btn--primary {
  color: var(--teal);
  border-color: var(--teal-a32);
  background-color: var(--teal-a08);
}

.btn--primary:hover,
.btn--primary:focus-visible {
  border-color: var(--teal);
  background-color: var(--teal-a16);
}

.btn--ghost:hover,
.btn--ghost:focus-visible {
  border-color: var(--text-mid);
  background-color: var(--paper-a06);
}

.btn--legacy {
  color: var(--violet-legacy);
  border-color: var(--violet-a28);
}

.btn--legacy:hover,
.btn--legacy:focus-visible {
  border-color: var(--violet-a50);
  background-color: var(--paper-a06);
}

/* ---------- 面包屑 ---------- */
.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 9px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.1em;
  color: var(--text-mid);
  padding-block: 22px;
}

.breadcrumb a {
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.breadcrumb a:hover,
.breadcrumb a:focus-visible {
  color: var(--text-hi);
  border-bottom-color: var(--hairline);
}

.breadcrumb__sep {
  color: var(--hairline);
}

/* ---------- 文字区块 ---------- */
.prose {
  max-width: 42em;
  font-size: 16.5px;
  line-height: 1.75;
  color: var(--text-mid);
}

.prose > * + * { margin-top: 0.9em; }

.prose h2 { margin-top: 1.6em; }
.prose h3 { margin-top: 1.4em; color: var(--text-hi); }
.prose ul, .prose ol { padding-left: 1.15em; }
.prose ul { list-style: none; }
.prose ol { list-style: decimal; }
.prose li { margin-top: 0.4em; }
.prose li::marker { color: var(--text-mid); }
.prose a {
  color: var(--teal);
  text-decoration: none;
  border-bottom: 1px solid var(--teal-a32);
}
.prose a:hover { border-bottom-color: var(--teal); }

.lede {
  max-width: 40em;
  font-size: clamp(16px, 1.5vw, 19px);
  line-height: 1.7;
  color: var(--text-mid);
}

.display {
  font-family: var(--font-display);
  font-weight: 200;
  font-size: clamp(38px, 6vw, 96px);
  line-height: 1.02;
  letter-spacing: -0.02em;
  color: var(--text-hi);
}

.display--sm {
  font-size: clamp(28px, 3.6vw, 52px);
  line-height: 1.06;
}

.on-paper { color: var(--text-on-paper); }
.on-paper p, .on-paper .prose { color: rgba(20, 33, 58, 0.78); }

/* ---------- 展览标签与刻度 ---------- */
.exhibit-label {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--text-mid);
}

.exhibit-label__no {
  color: var(--teal);
  letter-spacing: 0.08em;
}

.exhibit-label__dot {
  width: 5px;
  height: 5px;
  border: 1px solid var(--teal);
  border-radius: 50%;
  flex: 0 0 auto;
}

.exhibit-label--legacy .exhibit-label__no,
.exhibit-label--legacy .exhibit-label__dot {
  color: var(--violet-legacy);
  border-color: var(--violet-legacy);
}

.chapter-head {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-bottom: 22px;
}

.tick-rule {
  flex: 1 1 auto;
  height: 6px;
  background-image: repeating-linear-gradient(
    90deg,
    var(--hairline) 0 1px,
    transparent 1px 13px
  );
}

/* ---------- 编号锚点与关键串 ---------- */
.step-no {
  font-family: var(--font-display);
  font-size: clamp(64px, 12vw, 160px);
  font-weight: 200;
  line-height: 0.8;
  letter-spacing: -0.045em;
  color: transparent;
  -webkit-text-stroke: 1px var(--hairline);
  user-select: none;
}

.step-no--solid {
  color: var(--ink-700);
  -webkit-text-stroke: 0;
}

.step-no--accent {
  -webkit-text-stroke-color: var(--teal-a56);
}

.mono {
  font-family: var(--font-mono);
  font-size: 0.92em;
  letter-spacing: 0.01em;
  white-space: nowrap;
  padding: 1px 6px;
  color: var(--text-hi);
  background-color: var(--paper-a06);
  border: 1px solid var(--paper-a10);
  border-radius: 2px;
}

.mono--amber {
  color: var(--amber);
  background-color: var(--amber-a08);
  border-color: var(--amber-a28);
}

.mono--teal {
  color: var(--teal);
  background-color: var(--teal-a08);
  border-color: var(--teal-a32);
}

.index-label {
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--text-mid);
}

/* ---------- 面板与清单 ---------- */
.panel {
  position: relative;
  padding: clamp(18px, 2.6vw, 30px);
  background-color: var(--ink-800);
  border: 1px solid var(--hairline);
  border-radius: 3px;
  transition: border-color var(--dur) var(--ease), box-shadow var(--dur) var(--ease),
              background-color var(--dur) var(--ease);
}

.panel:hover,
.panel:focus-within {
  border-color: var(--teal-a32);
  box-shadow: var(--shadow-hover);
}

.panel--legacy {
  filter: saturate(0.55);
  border-color: var(--violet-a28);
}

.panel--legacy:hover,
.panel--legacy:focus-within {
  border-color: var(--violet-a50);
  box-shadow: none;
}

.panel--paper {
  background-color: var(--paper);
  color: var(--text-on-paper);
  border-color: rgba(20, 33, 58, 0.18);
}

.panel--paper p { color: rgba(20, 33, 58, 0.78); }

.panel--paper .mono {
  color: var(--text-on-paper);
  background-color: rgba(20, 33, 58, 0.07);
  border-color: rgba(20, 33, 58, 0.16);
}

.panel__head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 14px;
  margin-bottom: 14px;
}

.panel__title {
  font-family: var(--font-display);
  font-size: 18px;
  font-weight: 400;
  letter-spacing: 0.005em;
  color: var(--text-hi);
  line-height: 1.35;
}

.panel--paper .panel__title { color: var(--text-on-paper); }

/* 勾选清单 */
.check-list {
  display: grid;
  gap: 0;
}

.check-item {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  min-height: 44px;
  padding: 11px 4px;
  border-bottom: 1px solid var(--hairline);
  font-size: 14.5px;
  line-height: 1.6;
  color: var(--text-mid);
  transition: color var(--dur) var(--ease), background-color var(--dur) var(--ease);
}

.check-item:last-child { border-bottom: 0; }

.check-item:hover {
  color: var(--text-hi);
  background-color: var(--paper-a06);
}

.check-item__box {
  flex: 0 0 auto;
  width: 15px;
  height: 15px;
  margin-top: 4px;
  border: 1px solid var(--hairline);
  border-radius: 2px;
  position: relative;
  transition: border-color var(--dur) var(--ease), background-color var(--dur) var(--ease);
}

.check-item[data-checked] .check-item__box,
.check-item input:checked + .check-item__box {
  border-color: var(--teal);
  background-color: var(--teal-a16);
}

.check-item[data-checked] .check-item__box::after,
.check-item input:checked + .check-item__box::after {
  content: "";
  position: absolute;
  left: 4px;
  top: 1px;
  width: 4px;
  height: 8px;
  border: solid var(--teal);
  border-width: 0 1px 1px 0;
  transform: rotate(42deg);
}

.check-item__text { flex: 1 1 auto; min-width: 0; }

/* 对比表 */
.compare {
  width: 100%;
  font-size: 14px;
}

.compare th,
.compare td {
  padding: 10px 12px;
  text-align: left;
  border-bottom: 1px solid var(--hairline);
  line-height: 1.6;
  vertical-align: top;
}

.compare thead th {
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 400;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--text-mid);
  border-bottom-color: var(--text-mid);
}

.compare tbody tr { height: 40px; }

.compare tbody tr:nth-child(even) {
  background-color: var(--ink-700);
}

.compare__legacy {
  filter: saturate(0.55);
  color: var(--violet-legacy);
}

/* 折叠问答 */
.faq {
  border-top: 1px solid var(--hairline);
}

.faq__item {
  border-bottom: 1px solid var(--hairline);
}

.faq__item > summary,
.faq__trigger {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  width: 100%;
  padding: 16px 2px;
  font-size: 15.5px;
  line-height: 1.6;
  color: var(--text-hi);
  cursor: pointer;
  list-style: none;
  transition: color var(--dur) var(--ease), background-color var(--dur) var(--ease);
}

.faq__item > summary::-webkit-details-marker { display: none; }

.faq__item > summary:hover,
.faq__trigger:hover { color: var(--teal); }

.faq__mark {
  flex: 0 0 auto;
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--text-mid);
  transition: color var(--dur) var(--ease);
}

.faq__item[open] > summary .faq__mark { color: var(--teal); }

.faq__panel {
  padding: 0 2px 20px;
  font-size: 15px;
  line-height: 1.75;
  color: var(--text-mid);
  max-width: 42em;
}

.faq__panel[hidden] { display: none; }

/* 锚点轨道 */
.anchor-rail {
  display: grid;
  gap: 2px;
}

.anchor-rail a {
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding: 9px 10px;
  font-size: 14px;
  line-height: 1.5;
  color: var(--text-mid);
  text-decoration: none;
  border-left: 1px solid var(--hairline);
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease),
              background-color var(--dur) var(--ease);
}

.anchor-rail a:hover,
.anchor-rail a:focus-visible {
  color: var(--text-hi);
  background-color: var(--paper-a06);
}

.anchor-rail a[aria-current="location"] {
  color: var(--text-hi);
  border-left-color: var(--teal);
  background-color: var(--teal-a08);
}

.anchor-rail__no {
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.08em;
  color: var(--teal);
}

.anchor-rail a[aria-current="location"] .anchor-rail__no { color: var(--teal); }

/* 标签 */
.tag {
  display: inline-flex;
  align-items: center;
  padding: 3px 8px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  line-height: 1.5;
  border-radius: 2px;
  border: 1px solid var(--hairline);
  color: var(--text-mid);
}

.tag--current {
  color: var(--teal);
  border-color: var(--teal-a32);
  background-color: var(--teal-a08);
}

.tag--todo {
  color: var(--amber);
  border-color: var(--amber-a28);
  background-color: var(--amber-a08);
}

.tag--legacy {
  color: var(--violet-legacy);
  border-color: var(--violet-a28);
  background-color: var(--paper-a06);
}

/* ---------- 图片容器（页面阶段放图使用） ---------- */
.figure {
  margin: 0;
}

.figure__frame {
  position: relative;
  overflow: hidden;
  aspect-ratio: 16 / 10;
  border: 1px solid var(--hairline);
  border-radius: 3px;
  background-color: var(--ink-800);
  background-image: linear-gradient(140deg, var(--ink-800), var(--ink-900) 62%);
}

.figure__frame > img,
.figure__frame > picture > img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.figure__frame::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  opacity: 0.18;
  background-image:
    linear-gradient(var(--hairline) 1px, transparent 1px),
    linear-gradient(90deg, var(--hairline) 1px, transparent 1px);
  background-size: 32px 32px;
}

.figure--portrait .figure__frame { aspect-ratio: 4 / 5; }
.figure--wide .figure__frame { aspect-ratio: 21 / 9; }
.figure--square .figure__frame { aspect-ratio: 1 / 1; }

.figure--skew .figure__frame {
  clip-path: polygon(0 6%, 100% 0, 100% 94%, 0 100%);
}

.figure--legacy .figure__frame {
  filter: saturate(0.55);
  border-color: var(--violet-a28);
}

.figure__caption {
  margin-top: 10px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.08em;
  line-height: 1.6;
  color: var(--text-mid);
}

/* ---------- 响应式 ---------- */
@media (max-width: 1080px) {
  .footer-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 899px) {
  :root { --nav-h: 58px; }

  .grid-12 { grid-template-columns: repeat(4, minmax(0, 1fr)); }
  .grid-12 > .col-3,
  .grid-12 > .col-4,
  .grid-12 > .col-5,
  .grid-12 > .col-6,
  .grid-12 > .col-7,
  .grid-12 > .col-8 { grid-column: span 4; }

  .brand__tag { display: none; }

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

  .nav {
    position: fixed;
    top: var(--nav-h);
    left: 0;
    right: 0;
    display: flex;
    flex-direction: column;
    align-items: stretch;
    justify-content: flex-start;
    gap: 0;
    margin-left: 0;
    padding: 8px var(--gutter) 26px;
    max-height: calc(100vh - var(--nav-h));
    overflow-y: auto;
    background-color: var(--ink-900);
    border-bottom: 1px solid var(--hairline);
    opacity: 0;
    visibility: hidden;
    transform: translateY(-6px);
    transition: opacity var(--dur) var(--ease), transform var(--dur) var(--ease),
                visibility var(--dur) linear;
  }

  .site-header[data-open] .nav {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
  }

  .nav__list {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    width: 100%;
  }

  .nav__item {
    border-bottom: 1px solid var(--hairline);
  }

  .nav__link {
    display: block;
    padding: 15px 2px;
    font-size: 16px;
    color: var(--text-hi);
  }

  .nav__link::after {
    left: 2px;
    right: auto;
    width: 26px;
    bottom: -1px;
  }

  .nav__tools {
    flex-direction: column;
    align-items: stretch;
    gap: 10px;
    margin-top: 18px;
  }

  .utility-link {
    justify-content: center;
    padding: 11px 12px;
  }

  .site-header[data-scrolled="true"] .site-header__inner { height: var(--nav-h); }

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

@media (max-width: 620px) {
  body { font-size: 16px; }

  .footer-grid { grid-template-columns: minmax(0, 1fr); }
  .footer-inner { padding-bottom: 26px; }

  .step-no { font-size: clamp(56px, 22vw, 104px); }

  .figure--wide .figure__frame { aspect-ratio: 16 / 10; }

  .compare th,
  .compare td { padding: 9px 8px; font-size: 13px; }
}

/* ---------- 动效与可访问性 ---------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }

  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
    transition-delay: 0ms !important;
  }

  .nav,
  .skip-link {
    transform: none !important;
  }

  .site-header[data-open] .nav {
    opacity: 1;
    visibility: visible;
  }
}

/* 高对比偏好下加强边界 */
@media (prefers-contrast: more) {
  :root {
    --hairline: #4A6288;
    --text-mid: #B8C4D6;
  }
}

/* ---------- 打印 ---------- */
@media print {
  .site-header,
  .skip-link,
  .breadcrumb,
  .scroll-progress,
  .btn { display: none !important; }

  body {
    padding-top: 0;
    background: #ffffff;
    color: #10151F;
    font-size: 12pt;
  }

  h1, h2, h3, h4, .panel__title { color: #10151F; }
  p, li, .prose { color: #2A3345; }

  .panel,
  .figure__frame {
    background: #ffffff;
    border-color: #B9C0CC;
    box-shadow: none;
  }

  .figure__frame::after { display: none; }

  .mono {
    color: #10151F;
    background: #F1EFE8;
    border-color: #B9C0CC;
  }

  .site-footer {
    background: #ffffff;
    color: #2A3345;
    border-top-color: #B9C0CC;
  }

  .footer-links a,
  .footer-col__title,
  .footer-legal,
  .footer-reminder { color: #2A3345; }
}