/* ==========================================================================
   PP电子 · 简体中文站  /assets/site.css
   共享层：reset · 变量 · 中文排印 · 页头 · 页脚 · 通用组件 · 基础网格
   ========================================================================== */

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

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-h, 106px) + 20px);
}

html.nav-locked { overflow: hidden; }

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

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

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

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

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

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

/* ---------- 变量 ---------- */
:root {
  /* 品牌色 */
  --pulse-violet: #6A2BE2;
  --pulse-violet-lift: #7B3DF0;
  --signal-cyan: #00B4D8;
  --cyan-ink: #00778F;
  --indigo-night: #150C2E;
  --pine-deep: #0E3B33;
  --amber-highland: #E0A233;
  --archive-wine: #7A1F3D;
  --paper-ivory: #F6F3EC;
  --lilac-mist: #E7E1FA;
  --ink-graphite: #1B1A22;
  --boundary-cloud: #C9C5D6;

  --ink-soft: #4A4757;
  --ink-mute: #6D6A7A;

  /* 字体 */
  --font-display: "Archivo Black", "Noto Sans SC", "PingFang SC",
                  "Microsoft YaHei", system-ui, -apple-system, sans-serif;
  --font-body: Inter, "Noto Sans SC", "PingFang SC", "Microsoft YaHei",
               system-ui, -apple-system, "Helvetica Neue", Arial, sans-serif;
  --font-mono: "IBM Plex Mono", "Noto Sans Mono", ui-monospace, SFMono-Regular,
               Menlo, Consolas, monospace;

  /* 圆角 / 骨架 */
  --r-lg: 28px;
  --r-md: 22px;
  --r-sm: 14px;
  --r-pill: 999px;
  --wrap: 1240px;
  --col-left: 220px;
  --col-right: 260px;
  --header-h: 106px;
  --ease: cubic-bezier(.22, .61, .36, 1);
}

/* ---------- 基础排印 ---------- */
body {
  background: var(--paper-ivory);
  color: var(--ink-graphite);
  font-family: var(--font-body);
  font-size: 17px;
  line-height: 1.85;
  letter-spacing: .01em;
  font-weight: 400;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

h1, h2, h3, h4 {
  font-family: var(--font-display);
  font-weight: 900;
  line-height: 1.05;
  letter-spacing: .02em;
}

:focus-visible {
  outline: 2px solid var(--pulse-violet);
  outline-offset: 3px;
  border-radius: 6px;
}

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

::selection { background: var(--pulse-violet); color: #fff; }

/* ---------- 工具与容器 ---------- */
.wrap {
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding-inline: clamp(18px, 4vw, 44px);
}

#main-content {
  display: block;
  padding-top: var(--header-h);
}

#main-content.main--flush { padding-top: 0; }

.skip-link {
  position: fixed;
  top: 10px;
  left: 10px;
  z-index: 200;
  display: inline-block;
  padding: 10px 20px;
  border-radius: var(--r-pill);
  background: var(--pulse-violet);
  color: #fff;
  font-size: 14px;
  font-weight: 700;
  letter-spacing: .04em;
  transform: translateY(-180%);
  transition: transform .16s var(--ease);
}

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

.section { padding-block: clamp(46px, 7vw, 96px); }

.section--pine,
.section--wine {
  margin-inline: clamp(12px, 3vw, 36px);
  padding-block: clamp(42px, 6vw, 84px);
  border-radius: var(--r-lg);
  color: var(--paper-ivory);
}

.section--pine { background: var(--pine-deep); }
.section--wine { background: var(--archive-wine); }

.section__head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: 14px 28px;
  margin-bottom: clamp(20px, 3vw, 40px);
}

.section__title {
  font-size: clamp(28px, 4vw, 48px);
  line-height: 1.05;
}

.section__meta {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .12em;
  color: var(--ink-mute);
}

.section--pine .section__meta,
.section--wine .section__meta { color: rgba(246, 243, 236, .66); }

/* ---------- 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 9px;
  padding: 12px 22px;
  border: 1px solid transparent;
  border-radius: var(--r-pill);
  font-size: 15px;
  font-weight: 700;
  letter-spacing: .02em;
  line-height: 1.2;
  white-space: nowrap;
  transition: transform .16s var(--ease), background-color .16s var(--ease),
              border-color .16s var(--ease), color .16s var(--ease);
}

.btn--pulse {
  background: var(--pulse-violet);
  color: #fff;
}

.btn--pulse:hover {
  background: var(--pulse-violet-lift);
  transform: translateX(4px);
}

.btn--ghost {
  border-color: var(--boundary-cloud);
  color: var(--ink-graphite);
}

.btn--ghost:hover {
  border-color: var(--pulse-violet);
  color: var(--pulse-violet);
  transform: translateX(4px);
}

.btn--light {
  border-color: rgba(246, 243, 236, .4);
  color: var(--paper-ivory);
}

.btn--light:hover {
  background: var(--paper-ivory);
  border-color: var(--paper-ivory);
  color: var(--indigo-night);
  transform: translateX(4px);
}

.btn--small { padding: 8px 16px; font-size: 14px; }

/* ---------- 标签 / 旁注 / 卡片 ---------- */
.badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 5px 13px;
  border: 1px solid var(--boundary-cloud);
  border-radius: var(--r-pill);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .1em;
  line-height: 1.6;
  color: var(--ink-soft);
}

.badge--violet {
  border-color: var(--pulse-violet);
  background: var(--lilac-mist);
  color: var(--pulse-violet);
}

.badge--amber {
  border-color: var(--amber-highland);
  background: rgba(224, 162, 51, .14);
  color: #8A610F;
}

.badge--wine {
  border-color: var(--archive-wine);
  background: rgba(122, 31, 61, .08);
  color: var(--archive-wine);
}

.note {
  border-left: 3px solid var(--signal-cyan);
  padding: 14px 0 14px 18px;
  font-family: var(--font-mono);
  font-size: 13px;
  line-height: 1.75;
  color: var(--ink-soft);
}

.note--amber { border-left-color: var(--amber-highland); }

.card {
  background: #fff;
  border: 1px solid var(--boundary-cloud);
  border-radius: var(--r-md);
  padding: clamp(20px, 2.6vw, 30px);
  transition: border-color .16s var(--ease), background-color .16s var(--ease);
}

.card:hover {
  border-color: var(--pulse-violet);
  background: #fff;
}

/* ---------- 图片容器基础规则 ---------- */
.media-frame {
  position: relative;
  display: block;
  width: 100%;
  aspect-ratio: 16 / 9;
  overflow: hidden;
  border: 1px solid var(--boundary-cloud);
  border-radius: var(--r-md);
  background: var(--lilac-mist);
}

.media-frame--wide { aspect-ratio: 21 / 9; }
.media-frame--tall { aspect-ratio: 4 / 5; }
.media-frame--square { aspect-ratio: 1 / 1; }

.media-frame img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.media-frame__label {
  position: absolute;
  left: 14px;
  bottom: 14px;
  padding: 4px 12px;
  border-radius: var(--r-pill);
  background: rgba(246, 243, 236, .92);
  color: var(--cyan-ink);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .16em;
  line-height: 1.7;
}

.cover .media-frame,
.section--pine .media-frame,
.section--wine .media-frame {
  border-color: rgba(246, 243, 236, .24);
  background: rgba(246, 243, 236, .08);
}

/* ---------- 面包屑 ---------- */
.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin-bottom: 18px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .1em;
  color: var(--ink-mute);
}

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

.breadcrumb li::after {
  content: "/";
  margin-left: 8px;
  color: var(--boundary-cloud);
}

.breadcrumb li:last-child::after { content: ""; }

.breadcrumb a:hover { color: var(--pulse-violet); }

/* ---------- 正文容器 ---------- */
.prose { max-width: 68ch; }

.prose p { margin-bottom: 1.1em; }

.prose p:last-child { margin-bottom: 0; }

.prose h2 {
  font-size: clamp(26px, 3.4vw, 40px);
  margin: 1.5em 0 .55em;
}

.prose h3 {
  font-family: var(--font-body);
  font-size: 22px;
  font-weight: 700;
  line-height: 1.35;
  margin: 1.4em 0 .5em;
}

.prose ul,
.prose ol {
  margin: 0 0 1.1em;
  padding-left: 1.1em;
}

.prose ul { list-style: disc; }
.prose ol { list-style: decimal; }
.prose li { margin-bottom: .4em; }

.prose a {
  color: var(--cyan-ink);
  text-decoration: underline;
  text-decoration-color: var(--signal-cyan);
  text-decoration-thickness: 2px;
  text-underline-offset: 4px;
  transition: color .16s var(--ease), text-decoration-color .16s var(--ease);
}

.prose a:hover {
  color: var(--pulse-violet);
  text-decoration-color: var(--pulse-violet);
}

/* ==========================================================================
   页头
   ========================================================================== */
.site-header {
  --nav-ink: var(--paper-ivory);
  --nav-dim: rgba(246, 243, 236, .68);
  --nav-hover: rgba(246, 243, 236, .12);
  --nav-line: rgba(246, 243, 236, .18);
  --nav-accent: #B79BFF;

  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 80;
  color: var(--nav-ink);
  background: transparent;
  transition: background-color .22s var(--ease), color .22s var(--ease),
              box-shadow .22s var(--ease);
}

.site-header.is-solid,
.site-header.is-nav-open {
  --nav-ink: var(--ink-graphite);
  --nav-dim: var(--ink-mute);
  --nav-hover: var(--lilac-mist);
  --nav-line: var(--boundary-cloud);
  --nav-accent: var(--pulse-violet);

  color: var(--nav-ink);
  background: var(--paper-ivory);
  box-shadow: 0 1px 0 var(--boundary-cloud), 0 18px 34px -30px rgba(21, 12, 46, .6);
}

.site-header.is-nav-open {
  --nav-ink: var(--paper-ivory);
  --nav-dim: rgba(246, 243, 236, .7);
  --nav-hover: rgba(246, 243, 236, .12);
  --nav-line: rgba(246, 243, 236, .2);
  --nav-accent: #B79BFF;

  color: var(--paper-ivory);
  background: var(--indigo-night);
  box-shadow: none;
}

/* 顶部等宽索引条 */
.header-rail {
  max-height: 46px;
  overflow: hidden;
  border-bottom: 1px solid var(--nav-line);
  transition: max-height .22s var(--ease), opacity .14s linear,
              visibility 0s linear 0s, border-color .22s var(--ease);
}

.site-header.is-solid .header-rail,
.site-header.is-nav-open .header-rail {
  max-height: 0;
  opacity: 0;
  visibility: hidden;
  border-bottom-color: transparent;
  transition: max-height .22s var(--ease), opacity .14s linear,
              visibility 0s linear .22s, border-color .22s var(--ease);
}

.header-rail__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  min-height: 34px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .14em;
  color: var(--nav-dim);
}

.header-rail__tag { line-height: 1.7; }

.header-rail__links {
  display: flex;
  align-items: center;
  gap: 20px;
}

.header-rail__links a {
  transition: color .16s var(--ease);
}

.header-rail__links a:hover { color: var(--nav-ink); }

/* 主横条 */
.header-bar { position: relative; }

.header-bar__inner {
  display: flex;
  align-items: center;
  gap: clamp(14px, 2.6vw, 34px);
  min-height: 72px;
  padding-block: 8px;
}

/* 品牌 */
.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  flex: none;
  margin-right: auto;
}

.brand__mark {
  position: relative;
  display: block;
  flex: none;
  width: 24px;
  height: 28px;
}

.brand__mark::before,
.brand__mark::after {
  content: "";
  position: absolute;
  bottom: 0;
  width: 7px;
  border-radius: var(--r-pill);
}

.brand__mark::before {
  left: 0;
  height: 28px;
  background: var(--pulse-violet);
}

.brand__mark::after {
  right: 0;
  height: 17px;
  background: var(--signal-cyan);
}

.brand__text {
  display: flex;
  flex-direction: column;
  line-height: 1.05;
}

.brand__name {
  font-family: var(--font-display);
  font-size: 21px;
  font-weight: 900;
  letter-spacing: .06em;
}

.brand__sub {
  margin-top: 3px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .22em;
  color: var(--nav-dim);
}

/* 移动菜单按钮 */
.nav-toggle {
  display: none;
  align-items: center;
  gap: 9px;
  padding: 9px 16px;
  border: 1px solid var(--nav-line);
  border-radius: var(--r-pill);
  color: var(--nav-ink);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .16em;
  transition: background-color .16s var(--ease), border-color .16s var(--ease);
}

.nav-toggle:hover { background: var(--nav-hover); }

.nav-toggle__bars {
  display: flex;
  flex-direction: column;
  gap: 4px;
  width: 16px;
}

.nav-toggle__bars i {
  display: block;
  height: 2px;
  border-radius: var(--r-pill);
  background: currentColor;
  transition: transform .16s var(--ease);
}

.nav-toggle[aria-expanded="true"] .nav-toggle__bars i:first-child {
  transform: translateY(3px) rotate(45deg);
}

.nav-toggle[aria-expanded="true"] .nav-toggle__bars i:last-child {
  transform: translateY(-3px) rotate(-45deg);
}

/* 导航 */
.site-nav {
  display: flex;
  align-items: center;
  gap: clamp(8px, 1.6vw, 22px);
}

.site-nav__list {
  display: flex;
  align-items: center;
  gap: 2px;
}

.site-nav__list a {
  position: relative;
  display: inline-flex;
  align-items: baseline;
  gap: 7px;
  padding: 9px 14px;
  border-radius: var(--r-pill);
  color: var(--nav-dim);
  transition: color .16s var(--ease), background-color .16s var(--ease);
}

.site-nav__list a:hover {
  color: var(--nav-ink);
  background: var(--nav-hover);
}

.site-nav__idx {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .08em;
  color: var(--nav-accent);
  opacity: .9;
}

.site-nav__label { font-size: 15px; font-weight: 500; }

.site-nav__list a[aria-current="page"] {
  color: var(--nav-ink);
  background: var(--nav-hover);
}

.site-nav__list a[aria-current="page"]::after {
  content: "";
  position: absolute;
  left: 16px;
  right: 16px;
  bottom: 3px;
  height: 2px;
  border-radius: var(--r-pill);
  background: var(--signal-cyan);
}

.site-nav__foot {
  display: flex;
  align-items: center;
  flex: none;
}

/* 滚动进度 */
.header-progress {
  position: absolute;
  left: 0;
  bottom: 0;
  display: block;
  width: 0;
  height: 2px;
  background: var(--signal-cyan);
  transition: width .1s linear, background-color .16s var(--ease);
}

.site-header.is-solid .header-progress { background: var(--pulse-violet); }

/* ==========================================================================
   页脚
   ========================================================================== */
.site-footer {
  margin-top: clamp(48px, 7vw, 96px);
  padding-top: clamp(46px, 7vw, 88px);
  background: var(--indigo-night);
  color: var(--paper-ivory);
}

.site-footer__inner {
  display: grid;
  grid-template-columns: minmax(0, 1.05fr) minmax(0, 1.5fr) minmax(0, 1fr);
  gap: clamp(28px, 4vw, 64px);
  padding-bottom: clamp(34px, 5vw, 62px);
}

.site-footer__brand { max-width: 34ch; }

.footer-lockup {
  font-family: var(--font-display);
  font-size: clamp(24px, 2.8vw, 34px);
  font-weight: 900;
  line-height: 1.12;
  letter-spacing: .03em;
}

.footer-tagline {
  margin-top: 16px;
  font-size: 16px;
  line-height: 1.8;
  color: rgba(246, 243, 236, .76);
}

.footer-note {
  margin-top: 14px;
  padding-top: 14px;
  border-top: 1px solid rgba(246, 243, 236, .16);
  font-family: var(--font-mono);
  font-size: 12px;
  line-height: 1.75;
  letter-spacing: .04em;
  color: var(--amber-highland);
}

.footer-cols {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 22px clamp(16px, 2.4vw, 32px);
}

.footer-col__title {
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 400;
  letter-spacing: .22em;
  line-height: 1.8;
  color: var(--signal-cyan);
}

.footer-col__list {
  margin-top: 14px;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.footer-col__list a {
  font-size: 15px;
  color: rgba(246, 243, 236, .82);
  transition: color .16s var(--ease), transform .16s var(--ease);
  display: inline-block;
}

.footer-col__list a:hover {
  color: var(--paper-ivory);
  transform: translateX(4px);
}

/* 客服面板（深松绿分区） */
.footer-contact {
  padding: clamp(20px, 2.4vw, 28px);
  border-radius: var(--r-md);
  background: var(--pine-deep);
}

.footer-contact__title {
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 400;
  letter-spacing: .22em;
  line-height: 1.8;
  color: var(--amber-highland);
}

.copy-btn {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  width: 100%;
  margin-top: 12px;
  padding: 11px 14px;
  border: 1px solid rgba(246, 243, 236, .26);
  border-radius: var(--r-pill);
  text-align: left;
  transition: border-color .16s var(--ease), background-color .16s var(--ease),
              transform .16s var(--ease);
}

.copy-btn:hover {
  border-color: var(--signal-cyan);
  transform: translateX(4px);
}

.copy-btn.is-copied { border-color: var(--amber-highland); }

.copy-btn__val {
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: .02em;
  color: var(--paper-ivory);
  word-break: break-all;
}

.copy-btn__hint {
  flex: none;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .14em;
  color: var(--signal-cyan);
}

.copy-btn.is-copied .copy-btn__hint { color: var(--amber-highland); }

.footer-contact__hours {
  margin-top: 14px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .1em;
  color: rgba(246, 243, 236, .68);
}

/* 底部法务行 */
.footer-base {
  border-top: 1px solid rgba(246, 243, 236, .16);
  padding-block: 22px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .06em;
  color: rgba(246, 243, 236, .62);
}

.footer-base__inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 8px 28px;
}

.footer-base__addr { min-width: min(100%, 320px); }
.footer-base__legal { color: rgba(246, 243, 236, .74); }
.footer-base__copy { color: rgba(246, 243, 236, .5); }

/* ==========================================================================
   基础网格与可复用模块
   ========================================================================== */
.grid-rail {
  display: grid;
  grid-template-columns: var(--col-left) minmax(0, 1fr) var(--col-right);
  gap: clamp(20px, 3vw, 48px);
  align-items: start;
}

.rail {
  position: sticky;
  top: calc(var(--header-h) + 18px);
}

.aside {
  font-size: 15px;
  color: var(--ink-soft);
}

/* 目录高亮协议 */
[data-toc] a {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 8px 12px;
  border-left: 2px solid var(--boundary-cloud);
  font-size: 14px;
  line-height: 1.6;
  color: var(--ink-mute);
  transition: color .16s var(--ease), border-color .16s var(--ease),
              background-color .16s var(--ease);
}

[data-toc] a:hover {
  color: var(--pulse-violet);
  border-left-color: var(--signal-cyan);
  background: var(--lilac-mist);
}

[data-toc] a[aria-current] {
  color: var(--pulse-violet);
  border-left-color: var(--pulse-violet);
  background: var(--lilac-mist);
}

/* 封面 */
.cover {
  position: relative;
  overflow: hidden;
  padding-top: calc(var(--header-h) + clamp(42px, 8vw, 104px));
  padding-bottom: clamp(46px, 8vw, 94px);
  border-radius: 0 0 var(--r-lg) var(--r-lg);
  background: var(--indigo-night);
  color: var(--paper-ivory);
}

.cover__inner {
  display: grid;
  grid-template-columns: minmax(0, 1.5fr) minmax(0, .68fr);
  gap: clamp(24px, 5vw, 64px);
  align-items: end;
}

.cover__eyebrow {
  margin-bottom: 20px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .24em;
  color: var(--signal-cyan);
}

.cover__title {
  font-size: clamp(44px, 8vw, 104px);
  line-height: 1;
  letter-spacing: .02em;
}

.cover__lead {
  max-width: 34ch;
  margin-top: 22px;
  font-size: clamp(17px, 1.5vw, 20px);
  line-height: 1.8;
  color: rgba(246, 243, 236, .78);
}

.cover__index {
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding-top: 16px;
  border-top: 1px solid rgba(246, 243, 236, .22);
}

.cover__index a {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 14px;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: .08em;
  color: rgba(246, 243, 236, .72);
  transition: color .16s var(--ease), transform .16s var(--ease);
}

.cover__index a:hover {
  color: var(--paper-ivory);
  transform: translateX(4px);
}

/* 索引条带 */
.index-strip {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.index-strip__item {
  display: grid;
  grid-template-columns: 64px minmax(0, 1fr) auto;
  gap: 14px 18px;
  align-items: baseline;
  padding: 17px 20px;
  border: 1px solid transparent;
  border-radius: var(--r-sm);
  transition: background-color .16s var(--ease), border-color .16s var(--ease);
}

.index-strip__item:hover {
  background: var(--lilac-mist);
  border-color: var(--boundary-cloud);
}

.index-strip__item.is-active {
  background: var(--lilac-mist);
  border-color: var(--pulse-violet);
}

.index-strip__num {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: .06em;
  color: var(--pulse-violet);
  transition: transform .16s var(--ease);
}

.index-strip__item:hover .index-strip__num { transform: translateX(4px); }

.index-strip__title {
  font-size: 22px;
  font-weight: 700;
  line-height: 1.3;
  letter-spacing: .01em;
}

.index-strip__meta {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .08em;
  color: var(--ink-mute);
  text-align: right;
}

/* 三步数字块 */
.steps {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(210px, 1fr));
  gap: clamp(18px, 3vw, 36px);
}

.step__num {
  display: block;
  font-family: var(--font-display);
  font-size: clamp(56px, 8vw, 104px);
  font-weight: 900;
  line-height: .86;
  letter-spacing: -.02em;
  color: var(--lilac-mist);
  -webkit-text-stroke: 2px var(--pulse-violet);
}

.step__title {
  margin-top: 16px;
  font-size: 22px;
  font-weight: 700;
  line-height: 1.3;
}

.step__desc {
  margin-top: 8px;
  font-size: 15px;
  line-height: 1.8;
  color: var(--ink-soft);
}

/* 时间线 */
.timeline {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: clamp(20px, 3vw, 34px);
  padding-left: clamp(18px, 3vw, 32px);
  border-left: 1px solid var(--boundary-cloud);
}

.timeline__node { position: relative; }

.timeline__node::before {
  content: "";
  position: absolute;
  top: 10px;
  left: calc(-1 * clamp(18px, 3vw, 32px) - 5px);
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--signal-cyan);
  transition: transform .16s var(--ease);
}

.timeline__node:hover::before,
.timeline__node:focus-within::before { transform: scale(1.35); }

.timeline__node--amber::before { background: var(--amber-highland); }
.timeline__node--wine::before { background: var(--archive-wine); }

.timeline__time {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .12em;
  color: var(--cyan-ink);
}

.timeline__title {
  margin-top: 5px;
  font-size: 22px;
  font-weight: 700;
  line-height: 1.32;
}

.timeline__title a { transition: color .16s var(--ease); }
.timeline__title a:hover { color: var(--pulse-violet); }

/* 回到顶部 */
.to-top {
  position: fixed;
  right: clamp(14px, 3vw, 32px);
  bottom: clamp(14px, 3vw, 32px);
  z-index: 70;
  display: inline-flex;
  align-items: center;
  gap: 9px;
  padding: 12px 20px;
  border-radius: var(--r-pill);
  background: var(--indigo-night);
  color: var(--paper-ivory);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .14em;
  box-shadow: 0 16px 36px -20px rgba(21, 12, 46, .95);
  opacity: 0;
  visibility: hidden;
  transform: translateY(10px);
  transition: opacity .18s var(--ease), transform .18s var(--ease),
              visibility 0s linear .18s, background-color .16s var(--ease);
}

.to-top.is-visible {
  opacity: 1;
  visibility: visible;
  transform: none;
  transition: opacity .18s var(--ease), transform .18s var(--ease),
              visibility 0s linear 0s, background-color .16s var(--ease);
}

.to-top:hover {
  background: var(--pulse-violet);
  transform: translateX(4px);
}

/* ==========================================================================
   响应式
   ========================================================================== */
@media (max-width: 1080px) {
  .grid-rail { grid-template-columns: minmax(0, 1fr); }
  .rail { position: static; }
  .site-footer__inner {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  }
  .footer-contact { grid-column: 1 / -1; }
}

@media (max-width: 920px) {
  :root { --header-h: 62px; }

  .header-rail { display: none; }

  .header-bar__inner { min-height: 62px; padding-block: 6px; }

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

  .site-nav {
    position: fixed;
    inset: 0;
    z-index: -1;
    display: flex;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: calc(var(--header-h) + 18px) clamp(18px, 6vw, 40px) 40px;
    overflow-y: auto;
    background: var(--indigo-night);
    color: var(--paper-ivory);
    opacity: 0;
    visibility: hidden;
    transform: translateY(-8px);
    transition: opacity .18s var(--ease), transform .18s var(--ease),
                visibility 0s linear .18s;
  }

  .site-nav[data-open] {
    opacity: 1;
    visibility: visible;
    transform: none;
    transition: opacity .18s var(--ease), transform .18s var(--ease),
                visibility 0s linear 0s;
  }

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

  .site-nav__list a {
    padding: 15px 4px;
    border-radius: 0;
    border-bottom: 1px solid rgba(246, 243, 236, .14);
    color: var(--paper-ivory);
    font-size: 20px;
    transition: color .16s var(--ease), transform .16s var(--ease);
  }

  .site-nav__list a:hover,
  .site-nav__list a[aria-current="page"] {
    background: transparent;
    color: var(--amber-highland);
    transform: translateX(4px);
  }

  .site-nav__list a[aria-current="page"]::after { display: none; }

  .site-nav__idx { font-size: 12px; }

  .site-nav__foot { margin-top: 24px; }

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

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

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

@media (max-width: 640px) {
  body { font-size: 16px; }

  .header-rail__inner { min-height: 30px; }

  .brand__name { font-size: 19px; }

  .index-strip__item {
    grid-template-columns: 44px minmax(0, 1fr);
    padding: 15px 14px;
  }

  .index-strip__meta { grid-column: 2; text-align: left; }

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

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

  .to-top { padding: 11px 16px; letter-spacing: .1em; }
}

/* ==========================================================================
   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: 0s !important;
  }
}