/* =========================================================
   lebo-future.com.cn — 共享样式 /assets/site.css
   ========================================================= */

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

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

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

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

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

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

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

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

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

hr { border: 0; border-top: 1px solid currentColor; }

/* ---------- 设计令牌 ---------- */
:root {
  --ink: #0F1B2A;
  --ink-2: #1B2C40;
  --paper: #F2EDE4;
  --paper-2: #E4DFD6;
  --brown: #241C16;
  --copper: #C4622D;
  --copper-deep: #8E4118;
  --copper-soft: #E08A4F;
  --cyan: #57E0D2;
  --cyan-deep: #1E8C82;
  --signal: #B23A2E;
  --gray: #6B6862;

  --rule: rgba(36, 28, 22, 0.16);
  --rule-dark: rgba(242, 237, 228, 0.16);
  --veil: rgba(242, 237, 228, 0.78);
  --veil-dim: rgba(242, 237, 228, 0.55);

  --wrap: 1240px;
  --rail: 240px;
  --gutter: clamp(18px, 4vw, 52px);
  --nav-h: 58px;

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

  --ease: cubic-bezier(0.2, 0.7, 0.3, 1);
  --dur: 0.16s;
}

/* ---------- 基础排版 ---------- */
body {
  min-height: 100vh;
  background-color: var(--paper);
  color: var(--brown);
  font-family: var(--font-sans);
  font-size: 16px;
  font-weight: 400;
  line-height: 1.75;
  letter-spacing: 0.01em;
  -webkit-font-smoothing: antialiased;
}

p + p { margin-top: 1.2em; }

h1, h2, h3, h4 {
  font-weight: 900;
  line-height: 1.15;
  letter-spacing: -0.02em;
}

strong, b { font-weight: 500; }

:focus-visible {
  outline: 2px solid var(--cyan-deep);
  outline-offset: 2px;
}

.section--ink :focus-visible,
.site-footer :focus-visible,
.brand-band :focus-visible,
.site-nav[data-open] :focus-visible {
  outline-color: var(--cyan);
}

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

/* ---------- 布局工具 ---------- */
.wrap {
  width: min(calc(100% - var(--gutter) * 2), var(--wrap));
  margin-inline: auto;
}

.wrap--wide { max-width: 1480px; }

.section {
  padding-block: clamp(48px, 7vw, 110px);
}

.section--tight { padding-block: clamp(26px, 4vw, 56px); }

.section--paper2 { background-color: var(--paper-2); }

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

.section--ink .t-lede { color: var(--veil); }

.grid {
  display: grid;
  gap: clamp(16px, 2.4vw, 32px);
}

.grid--2 { grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); }
.grid--3 { grid-template-columns: repeat(auto-fit, minmax(210px, 1fr)); }
.grid--stats { grid-template-columns: repeat(auto-fit, minmax(168px, 1fr)); }

.offset { padding-left: clamp(0px, 6vw, 88px); }

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: -1px;
  padding: 0;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
  border: 0;
}

/* ---------- 文字阶梯 ---------- */
.t-display {
  font-size: clamp(2.75rem, 7.2vw, 7.5rem);
  font-weight: 900;
  line-height: 1.02;
  letter-spacing: -0.035em;
}

.t-h1 {
  font-size: clamp(2rem, 4.2vw, 3.5rem);
  font-weight: 900;
  line-height: 1.1;
  letter-spacing: -0.028em;
}

.t-h2 {
  font-size: clamp(1.5rem, 2.6vw, 2.25rem);
  font-weight: 900;
  letter-spacing: -0.022em;
}

.t-h3 {
  font-size: 1.25rem;
  font-weight: 900;
  letter-spacing: -0.012em;
}

.t-lede {
  font-size: clamp(1.0625rem, 1.6vw, 1.375rem);
  line-height: 1.72;
  color: #3a322a;
  max-width: 62ch;
}

.mono {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  letter-spacing: 0.02em;
}

.cap {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--gray);
}

.rot-label {
  writing-mode: vertical-rl;
  text-orientation: mixed;
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.22em;
  color: var(--gray);
}

/* ---------- 跳转链接 ---------- */
.skip-link {
  position: absolute;
  left: var(--gutter);
  top: 0;
  z-index: 200;
  transform: translateY(-130%);
  background-color: var(--copper);
  color: #fff;
  padding: 0.7rem 1.1rem;
  font-size: 0.875rem;
  font-weight: 500;
  letter-spacing: 0.04em;
  transition: transform var(--dur) var(--ease);
}

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

/* ---------- 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5em;
  padding: 0.58em 1.05em;
  border: 1px solid transparent;
  font-size: 0.8125rem;
  font-weight: 500;
  letter-spacing: 0.06em;
  line-height: 1.4;
  white-space: nowrap;
  cursor: pointer;
  transition: background-color var(--dur) var(--ease),
    color var(--dur) var(--ease),
    border-color var(--dur) var(--ease),
    transform var(--dur) var(--ease);
}

.btn:active { transform: translateY(1px); }

.btn--cut {
  clip-path: polygon(9px 0, 100% 0, 100% calc(100% - 9px),
    calc(100% - 9px) 100%, 0 100%, 0 9px);
}

.btn--copper {
  background-color: var(--copper);
  border-color: var(--copper);
  color: #fff;
}

.btn--copper:hover {
  background-color: var(--copper-soft);
  border-color: var(--copper-soft);
}

.btn--ghost {
  border-color: var(--rule-dark);
  color: var(--paper);
}

.btn--ghost:hover {
  border-color: var(--copper-soft);
  color: var(--copper-soft);
}

.btn--line {
  border-color: var(--copper);
  color: var(--copper-deep);
}

.btn--line:hover {
  background-color: var(--copper);
  color: #fff;
}

.btn--cyan {
  background-color: var(--cyan);
  border-color: var(--cyan);
  color: var(--ink);
}

.btn--cyan:hover { background-color: #7ff0e4; border-color: #7ff0e4; }

/* =========================================================
   页头
   ========================================================= */
.site-header {
  position: relative;
  z-index: 60;
}

/* --- 上层：墨蓝品牌带 --- */
.brand-band {
  background-color: var(--ink);
  color: var(--paper);
  border-bottom: 1px solid var(--rule-dark);
}

.brand-band__row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.55rem clamp(12px, 2.2vw, 30px);
  padding-block: 0.62rem;
}

.brand-mark {
  display: inline-flex;
  align-items: baseline;
  gap: 0.55rem;
  flex: 0 0 auto;
}

.brand-mark__cn {
  font-size: 1.02rem;
  font-weight: 900;
  letter-spacing: 0.02em;
}

.brand-mark__en {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.24em;
  color: var(--copper-soft);
  transition: color var(--dur) var(--ease);
}

.brand-mark:hover .brand-mark__en { color: var(--cyan); }

.brand-band__tagline {
  font-size: 0.8125rem;
  letter-spacing: 0.06em;
  color: var(--veil-dim);
  padding-left: clamp(12px, 2.2vw, 30px);
  border-left: 1px solid var(--rule-dark);
}

.brand-band__note {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.04em;
  color: var(--cyan);
}

.brand-band__note::before {
  content: "";
  flex: none;
  width: 6px;
  height: 6px;
  background-color: var(--cyan);
}

.brand-band__cta {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  flex: 0 0 auto;
}

/* --- 下层：粘性主导航带 --- */
.nav-band {
  position: sticky;
  top: 0;
  z-index: 70;
  background-color: var(--paper);
  border-bottom: 1px solid var(--rule);
}

.nav-band__row {
  position: relative;
  display: flex;
  align-items: center;
  gap: clamp(12px, 3vw, 40px);
  min-height: var(--nav-h);
}

.site-nav { margin-left: auto; }

.site-nav__list {
  display: flex;
  align-items: center;
  gap: clamp(6px, 1.8vw, 28px);
  counter-reset: navc;
}

.site-nav__list li { counter-increment: navc; }

.site-nav__list a {
  position: relative;
  display: inline-block;
  padding: 0.95rem 0;
  font-size: 0.9rem;
  font-weight: 500;
  letter-spacing: 0.02em;
  color: var(--brown);
  transition: color var(--dur) var(--ease);
}

.site-nav__list a::before {
  content: "0" counter(navc);
  margin-right: 0.5em;
  font-family: var(--font-mono);
  font-size: 0.6rem;
  letter-spacing: 0.12em;
  color: var(--gray);
  vertical-align: 0.2em;
  transition: color var(--dur) var(--ease);
}

.site-nav__list a::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0.6rem;
  height: 2px;
  background-color: var(--copper);
  transform: scaleX(0);
  transform-origin: 0 50%;
  transition: transform 0.18s var(--ease);
}

.site-nav__list a:hover { color: var(--copper-deep); }

.site-nav__list a:hover::after,
.site-nav__list a[aria-current="page"]::after { transform: scaleX(1); }

.site-nav__list a[aria-current="page"] { color: var(--copper-deep); }

.site-nav__list a[aria-current="page"]::before { color: var(--copper); }

/* 移动端按钮 */
.nav-toggle {
  display: none;
  align-items: center;
  gap: 0.55rem;
  margin-left: auto;
  padding: 0.5rem 0;
  border-top: 2px solid var(--copper);
  border-bottom: 2px solid var(--copper);
  font-size: 0.85rem;
  font-weight: 500;
  letter-spacing: 0.1em;
  color: var(--brown);
  transition: color var(--dur) var(--ease);
}

.nav-toggle__bars {
  position: relative;
  flex: none;
  width: 18px;
  height: 10px;
}

.nav-toggle__bars::before,
.nav-toggle__bars::after {
  content: "";
  position: absolute;
  left: 0;
  width: 100%;
  height: 1.5px;
  background-color: currentColor;
  transition: transform var(--dur) var(--ease), top var(--dur) var(--ease);
}

.nav-toggle__bars::before { top: 0; }
.nav-toggle__bars::after { top: 8px; }

.nav-toggle[aria-expanded="true"] { color: var(--copper-deep); }
.nav-toggle[aria-expanded="true"] .nav-toggle__bars::before { top: 4px; transform: rotate(45deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle__bars::after { top: 4px; transform: rotate(-45deg); }

/* 滚动进度 */
.scroll-progress {
  position: absolute;
  left: 0;
  right: 0;
  bottom: -1px;
  height: 2px;
  overflow: hidden;
  pointer-events: none;
}

.scroll-progress__fill {
  display: block;
  width: 100%;
  height: 100%;
  background-image: linear-gradient(90deg, var(--copper), var(--copper-soft));
  transform: scaleX(var(--p, 0));
  transform-origin: 0 50%;
}

/* =========================================================
   页脚
   ========================================================= */
.site-footer {
  background-color: var(--ink);
  color: var(--paper);
}

.foot-rail {
  height: 13px;
  border-bottom: 1px solid var(--rule-dark);
  background-image: repeating-linear-gradient(
    90deg,
    var(--copper) 0 1px,
    transparent 1px 13px
  );
  opacity: 0.45;
}

.site-footer__inner {
  display: grid;
  grid-template-columns: minmax(220px, 1.1fr) minmax(0, 2fr) minmax(230px, 1fr);
  gap: clamp(28px, 4vw, 64px);
  padding-block: clamp(36px, 5vw, 68px);
}

.site-footer__brand { min-width: 0; }

.foot-brand {
  font-size: 1.35rem;
  font-weight: 900;
  letter-spacing: -0.01em;
}

.foot-brand__en {
  margin-left: 0.45em;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.24em;
  color: var(--copper-soft);
  vertical-align: 0.18em;
}

.foot-brand__line {
  margin-top: 0.6rem;
  font-size: 0.8125rem;
  letter-spacing: 0.06em;
  color: var(--veil-dim);
}

.foot-brand__legal {
  margin-top: 1rem;
  max-width: 34ch;
  font-size: 0.75rem;
  line-height: 1.75;
  color: rgba(242, 237, 228, 0.45);
}

.foot-cols {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: clamp(16px, 2.4vw, 34px);
}

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

.foot-title {
  padding-bottom: 0.6rem;
  margin-bottom: 0.9rem;
  border-bottom: 1px solid var(--rule-dark);
  font-family: var(--font-mono);
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.16em;
  color: var(--copper-soft);
}

.foot-list {
  display: grid;
  gap: 0.5rem;
}

.foot-list a {
  position: relative;
  display: inline-block;
  font-size: 0.85rem;
  color: var(--veil);
  transition: color var(--dur) var(--ease);
}

.foot-list a::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -2px;
  width: 100%;
  height: 1px;
  background-color: var(--cyan);
  transform: scaleX(0);
  transform-origin: 0 50%;
  transition: transform var(--dur) var(--ease);
}

.foot-list a:hover { color: #fff; }
.foot-list a:hover::after { transform: scaleX(1); }

.foot-contact__list {
  display: grid;
  gap: 0.8rem;
}

.foot-contact__list li {
  display: grid;
  gap: 0.15rem;
}

.foot-k {
  font-family: var(--font-mono);
  font-size: 0.65rem;
  letter-spacing: 0.14em;
  color: rgba(242, 237, 228, 0.42);
}

.foot-v {
  font-size: 0.8125rem;
  line-height: 1.6;
  color: rgba(242, 237, 228, 0.86);
  overflow-wrap: anywhere;
}

.foot-v--mono {
  font-family: var(--font-mono);
  letter-spacing: 0.03em;
}

.foot-base {
  border-top: 1px solid var(--rule-dark);
}

.foot-base__row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.6rem 1.5rem;
  padding-block: 1rem;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.06em;
  color: rgba(242, 237, 228, 0.5);
}

.foot-base__links {
  display: flex;
  flex-wrap: wrap;
  gap: 1.2rem;
  margin-left: auto;
}

.foot-base__links a {
  color: rgba(242, 237, 228, 0.72);
  transition: color var(--dur) var(--ease);
}

.foot-base__links a:hover { color: var(--cyan); }

.foot-icp { color: rgba(242, 237, 228, 0.42); }

/* =========================================================
   通用内容组件
   ========================================================= */

/* --- 面包屑 --- */
.crumbs {
  padding-block: 1rem;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.08em;
  color: var(--gray);
}

.crumbs ol {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.5rem;
}

.crumbs li {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
}

.crumbs li::after {
  content: "/";
  color: rgba(36, 28, 22, 0.3);
}

.crumbs li:last-child::after { content: none; }

.crumbs a { transition: color var(--dur) var(--ease); }
.crumbs a:hover { color: var(--copper-deep); }
.crumbs [aria-current="page"] { color: var(--brown); }

/* --- 左索引右内容 --- */
.layout-split {
  display: grid;
  grid-template-columns: var(--rail) minmax(0, 1fr);
  gap: clamp(24px, 4vw, 72px);
  align-items: start;
}

.rail {
  position: sticky;
  top: calc(var(--nav-h) + 16px);
  padding-top: 1rem;
  border-top: 2px solid var(--copper);
}

.rail__title {
  margin-bottom: 0.85rem;
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.16em;
  color: var(--gray);
}

.rail__list {
  display: grid;
  gap: 2px;
}

.rail__link {
  display: flex;
  align-items: baseline;
  gap: 0.6rem;
  padding: 0.5rem 0.6rem 0.5rem 0.1rem;
  border-left: 2px solid transparent;
  font-size: 0.85rem;
  color: var(--gray);
  transition: color var(--dur) var(--ease),
    border-color var(--dur) var(--ease),
    background-color var(--dur) var(--ease),
    padding-left var(--dur) var(--ease);
}

.rail__link:hover {
  padding-left: 0.42rem;
  color: var(--brown);
  border-left-color: var(--copper-soft);
  background-color: rgba(196, 98, 45, 0.06);
}

.rail__link[aria-current="true"] {
  font-weight: 500;
  color: var(--copper-deep);
  border-left-color: var(--copper);
}

.rail__no {
  font-family: var(--font-mono);
  font-size: 0.65rem;
  color: var(--copper);
}

.rail__stamp {
  margin-top: 1.3rem;
  font-family: var(--font-mono);
  font-size: 0.65rem;
  line-height: 1.85;
  letter-spacing: 0.04em;
  color: var(--gray);
}

/* --- 展板 --- */
.board {
  position: relative;
  margin-top: clamp(32px, 5vw, 68px);
  padding-top: 1.3rem;
  border-top: 1px solid var(--rule);
}

.board:first-child { margin-top: 0; }

.board__label {
  position: absolute;
  top: -0.72em;
  left: 0;
  padding-right: 0.75rem;
  background-color: var(--paper);
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.16em;
  color: var(--copper);
}

.section--ink .board { border-top-color: var(--rule-dark); }
.section--ink .board__label { background-color: var(--ink); }
.section--paper2 .board__label { background-color: var(--paper-2); }

.board__title {
  margin-bottom: 0.5rem;
  font-size: clamp(1.35rem, 2.4vw, 2rem);
  font-weight: 900;
  letter-spacing: -0.022em;
}

/* --- 关键数字 --- */
.stat {
  display: grid;
  gap: 0.35rem;
}

.stat__num {
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: clamp(2.75rem, 7vw, 6rem);
  line-height: 0.95;
  letter-spacing: -0.03em;
  color: var(--brown);
}

.section--ink .stat__num { color: var(--paper); }

.stat__num--copper { color: var(--copper); }
.stat__num--cyan { color: var(--cyan); }
.section--ink .stat__num--cyan { color: var(--cyan); }

.stat__cap {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  line-height: 1.6;
  letter-spacing: 0.08em;
  color: var(--gray);
}

.section--ink .stat__cap { color: var(--veil-dim); }

/* --- 数据归纳条 --- */
.data-bar {
  padding-block: clamp(20px, 3vw, 34px);
  background-color: var(--ink-2);
  border-top: 2px solid var(--copper);
  border-bottom: 1px solid var(--rule-dark);
  color: var(--paper);
}

.data-bar__grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: clamp(16px, 2.5vw, 36px);
}

/* --- 参数抽屉 --- */
.drawer { border-top: 1px solid var(--rule); }
.drawer:last-child { border-bottom: 1px solid var(--rule); }

.section--ink .drawer { border-top-color: var(--rule-dark); }
.section--ink .drawer:last-child { border-bottom-color: var(--rule-dark); }

.drawer__head {
  display: flex;
  align-items: baseline;
  gap: 1rem;
  width: 100%;
  padding: 1.05rem 0;
  text-align: left;
}

.drawer__title {
  font-size: 1rem;
  font-weight: 500;
  letter-spacing: 0.01em;
  transition: color var(--dur) var(--ease);
}

.drawer__head:hover .drawer__title { color: var(--copper-deep); }

.section--ink .drawer__head:hover .drawer__title { color: var(--cyan); }

.drawer__meta {
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.06em;
  color: var(--gray);
}

.section--ink .drawer__meta { color: var(--veil-dim); }

.drawer__sign {
  position: relative;
  flex: none;
  width: 12px;
  height: 12px;
  align-self: center;
}

.drawer__sign::before,
.drawer__sign::after {
  content: "";
  position: absolute;
  background-color: var(--copper);
}

.drawer__sign::before { left: 0; top: 5px; width: 12px; height: 2px; }
.drawer__sign::after { left: 5px; top: 0; width: 2px; height: 12px; transition: transform var(--dur) var(--ease); }

.drawer__head[aria-expanded="true"] .drawer__sign::after { transform: scaleY(0); }

.drawer__body {
  display: none;
  padding-bottom: 1.25rem;
  font-size: 0.9375rem;
}

.drawer__body[data-open] { display: block; }

/* --- 变更对照 --- */
.diff__row {
  display: grid;
  grid-template-columns: minmax(130px, 0.9fr) 1fr 1fr;
  gap: 1rem;
  padding: 0.7rem 0;
  border-bottom: 1px solid var(--rule);
  font-size: 0.875rem;
}

.section--ink .diff__row { border-bottom-color: var(--rule-dark); }

.diff__key {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--gray);
}

.diff__before {
  color: var(--gray);
  text-decoration: line-through;
  text-decoration-color: rgba(178, 58, 46, 0.55);
}

.diff__after { color: var(--brown); font-weight: 500; }
.section--ink .diff__after { color: var(--paper); }

.diff__mark {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.06em;
  color: var(--signal);
}

.section--ink .diff__mark { color: var(--cyan); }

/* --- 表格 --- */
.table-scroll {
  overflow-x: auto;
  border: 1px solid var(--rule);
  background-color: var(--paper);
  -webkit-overflow-scrolling: touch;
}

.data-table {
  min-width: 640px;
  font-size: 0.85rem;
}

.data-table th,
.data-table td {
  padding: 0.7rem 0.9rem;
  text-align: left;
  border-bottom: 1px solid var(--rule);
  vertical-align: top;
}

.data-table thead th {
  position: sticky;
  top: 0;
  background-color: var(--paper-2);
  font-family: var(--font-mono);
  font-size: 0.68rem;
  font-weight: 500;
  letter-spacing: 0.1em;
  color: var(--gray);
}

.data-table tbody tr:hover { background-color: rgba(196, 98, 45, 0.05); }

/* --- 时间轴 --- */
.timeline {
  position: relative;
  padding-left: 28px;
}

.timeline::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 6px;
  bottom: 6px;
  width: 1px;
  background-color: var(--rule);
}

.section--ink .timeline::before { background-color: var(--rule-dark); }

.timeline__node {
  position: relative;
  padding-bottom: clamp(20px, 3vw, 36px);
}

.timeline__node::before {
  content: "";
  position: absolute;
  left: -28px;
  top: 0.5em;
  width: 11px;
  height: 11px;
  background-color: var(--paper);
  border: 2px solid var(--copper);
  transition: transform var(--dur) var(--ease), background-color var(--dur) var(--ease);
}

.section--ink .timeline__node::before { background-color: var(--ink); }

.timeline__node:hover::before {
  transform: scale(1.08);
  background-color: var(--copper);
}

/* --- 标签 --- */
.tag {
  display: inline-flex;
  align-items: center;
  gap: 0.4em;
  padding: 0.28em 0.6em;
  border: 1px solid currentColor;
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.08em;
  color: var(--copper-deep);
}

.tag--cyan { color: var(--cyan-deep); }
.tag--signal { color: var(--signal); }
.tag--dark {
  background-color: var(--ink);
  border-color: var(--ink);
  color: var(--paper);
}

/* --- 复制按钮 --- */
.copy-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5em;
  padding: 0.5em 0.9em;
  border: 1px solid var(--copper);
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.08em;
  color: var(--copper-deep);
  transition: background-color var(--dur) var(--ease), color var(--dur) var(--ease);
}

.copy-btn:hover { background-color: var(--copper); color: #fff; }

.copy-btn[data-copied] {
  background-color: var(--cyan-deep);
  border-color: var(--cyan-deep);
  color: #fff;
}

/* --- 图片容器 --- */
.media-frame {
  position: relative;
  overflow: hidden;
  aspect-ratio: 16 / 10;
  background-color: var(--ink-2);
}

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

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

.media-frame--empty::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image: repeating-linear-gradient(
      135deg,
      rgba(242, 237, 228, 0.06) 0 8px,
      transparent 8px 16px
    );
  background-color: var(--ink-2);
}

.media-frame--cyanotype img {
  filter: grayscale(1) brightness(0.9) contrast(1.08);
}

.media-frame--cyanotype::after {
  content: "";
  position: absolute;
  inset: 0;
  background-color: var(--ink);
  mix-blend-mode: color;
  opacity: 0.55;
  pointer-events: none;
}

.media-frame__cap {
  position: absolute;
  left: 0;
  bottom: 0;
  padding: 0.42rem 0.75rem;
  background-color: var(--ink);
  color: var(--paper);
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.06em;
}

/* =========================================================
   响应式
   ========================================================= */
@media (max-width: 1100px) {
  .site-footer__inner {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1.6fr);
  }
  .foot-contact { grid-column: 1 / -1; }
}

@media (max-width: 1000px) {
  .layout-split { grid-template-columns: minmax(0, 1fr); }
  .rail {
    position: static;
    padding-top: 0.85rem;
    padding-bottom: 0.4rem;
  }
  .rail__list {
    display: flex;
    flex-wrap: wrap;
    gap: 0.4rem;
  }
  .rail__link {
    border: 1px solid var(--rule);
    border-left-width: 2px;
    padding: 0.4rem 0.7rem;
  }
}

@media (max-width: 900px) {
  .brand-band__note { display: none; }

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

  .site-nav {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    margin-left: 0;
    padding: 0.35rem 0 1.1rem;
    background-color: var(--ink);
    border-top: 1px solid var(--copper);
    border-bottom: 1px solid var(--copper);
    box-shadow: 0 18px 34px rgba(15, 27, 42, 0.3);
  }

  .site-nav[data-open] { display: block; }

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

  .site-nav__list a {
    display: block;
    padding: 0.95rem 0;
    border-bottom: 1px solid var(--rule-dark);
    font-size: 1rem;
    color: var(--paper);
  }

  .site-nav__list a::before { color: var(--copper-soft); }
  .site-nav__list a::after { display: none; }
  .site-nav__list a[aria-current="page"] { color: var(--cyan); }
  .site-nav__list a[aria-current="page"]::before { color: var(--cyan); }
  .site-nav__list li:last-child a { border-bottom: 0; }
}

@media (max-width: 880px) {
  .site-footer__inner {
    grid-template-columns: minmax(0, 1fr);
  }
  .foot-cols {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 1.6rem;
  }
  .foot-base__links { margin-left: 0; width: 100%; }
}

@media (max-width: 736px) {
  body { font-size: 17px; }

  .brand-band__row { padding-block: 0.55rem; }
  .brand-band__tagline { display: none; }
  .brand-band__cta { gap: 0.4rem; }
  .brand-band__cta .btn { font-size: 0.75rem; padding: 0.5em 0.75em; }

  .crumbs { font-size: 0.66rem; }
  .diff__row {
    grid-template-columns: minmax(0, 1fr);
    gap: 0.2rem;
  }
}

@media (max-width: 560px) {
  .foot-cols { grid-template-columns: minmax(0, 1fr); }
  .foot-base__row { gap: 0.5rem 1rem; }
}

/* =========================================================
   无障碍与动效退化
   ========================================================= */
@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;
    scroll-behavior: auto !important;
  }

  .timeline__node:hover::before { transform: none; }
  .btn:active { transform: none; }
}