/* ==========================================================================
   PP王电子 · 王电子指南 — 共享样式 /assets/site.css
   原型：技术蓝图网格 + 电子仪器前面板
   ========================================================================== */

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

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

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

ul, ol { list-style: none; }

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

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

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

[hidden] { display: none !important; }

/* ---------- 设计令牌 ---------- */
:root {
  --ink: #0C1116;
  --ink-2: #161C22;
  --panel: #E9EDF0;
  --white: #FAFBFC;
  --silver: #96A2AB;
  --silver-soft: #C9D3DA;
  --rule: #C6CFD6;
  --blue: #0E6BA8;
  --blue-deep: #08405F;
  --amber: #D69A2D;
  --orange: #D2541C;
  --orange-deep: #8F3512;
  --focus: #7FD3F0;

  --font-display: "Archivo Narrow", "Noto Sans SC", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --font-body: "Noto Sans SC", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --font-mono: "IBM Plex Mono", "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;

  --fs-12: 0.75rem;
  --fs-14: 0.875rem;
  --fs-17: 1.0625rem;
  --fs-21: 1.3125rem;
  --fs-28: 1.75rem;
  --fs-40: 2.5rem;
  --fs-64: 4rem;

  --shell: min(1240px, 100% - 3rem);
  --shell-narrow: min(760px, 100% - 3rem);
  --header-h: 70px;

  --dur-1: 150ms;
  --dur-2: 260ms;
  --ease: cubic-bezier(.22, .61, .36, 1);

  --shadow-1: 0 10px 26px -20px rgba(12, 17, 22, .70);
  --shadow-2: 0 22px 46px -28px rgba(12, 17, 22, .88);

  --radius-sm: 3px;
  --radius: 8px;
}

/* ---------- 中文正文与全局排版 ---------- */
body {
  font-family: var(--font-body);
  font-size: var(--fs-17);
  line-height: 1.75;
  color: var(--ink);
  background-color: var(--white);
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
}

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

::selection { background: var(--blue); color: var(--white); }

/* ---------- 跳转链接 ---------- */
.skip-link {
  position: absolute;
  left: 50%;
  top: .5rem;
  transform: translate(-50%, -240%);
  z-index: 200;
  padding: .6rem 1.1rem;
  background: var(--blue);
  color: #FFFFFF;
  font-size: var(--fs-14);
  border-radius: 2px;
  transition: transform var(--dur-2) var(--ease);
}

.skip-link:focus { transform: translate(-50%, 0); }

/* ---------- 布局容器 ---------- */
.shell { width: var(--shell); margin-inline: auto; }
.shell--narrow { width: var(--shell-narrow); margin-inline: auto; }
.shell--wide { width: min(1440px, 100% - 2rem); margin-inline: auto; }

.section { padding-block: clamp(2.75rem, 6vw, 6rem); }
.section--ink { background-color: var(--ink); color: var(--white); }
.section--panel { background-color: var(--panel); color: var(--ink); }
.section--rule { border-top: 1px solid var(--rule); }

.grid-bg {
  background-image:
    linear-gradient(to right, rgba(150, 162, 171, .09) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(150, 162, 171, .09) 1px, transparent 1px);
  background-size: 72px 72px;
}

.grid-bg--light {
  background-image:
    linear-gradient(to right, rgba(150, 162, 171, .26) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(150, 162, 171, .26) 1px, transparent 1px);
  background-size: 72px 72px;
}

.grid { display: grid; gap: clamp(1.25rem, 3vw, 2.5rem); }
.grid--2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid--3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.grid--62 { grid-template-columns: minmax(0, 1.65fr) minmax(0, 1fr); }
.grid--58 { grid-template-columns: minmax(0, 1.4fr) minmax(0, 1fr); }

/* ---------- 文字层级 ---------- */
.display {
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(2.25rem, 7vw, var(--fs-64));
  line-height: 1.02;
  letter-spacing: -.01em;
  text-transform: uppercase;
}

.h-1 {
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(1.75rem, 3.4vw, var(--fs-40));
  line-height: 1.12;
  letter-spacing: -.01em;
}

.h-2 {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: var(--fs-28);
  line-height: 1.2;
  letter-spacing: -.005em;
}

.h-3 {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: var(--fs-21);
  line-height: 1.3;
}

.lede {
  font-size: var(--fs-21);
  line-height: 1.62;
  color: var(--blue-deep);
  max-width: 34em;
}

.lede--dark { color: var(--silver-soft); }

.eyebrow {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: .18em;
  text-transform: uppercase;
  color: var(--blue);
}

.eyebrow--amber { color: var(--amber); }
.eyebrow--dark { color: var(--focus); }

.mono {
  font-family: var(--font-mono);
  font-size: var(--fs-14);
  letter-spacing: .02em;
  font-variant-numeric: tabular-nums;
}

.index-num {
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: .12em;
  color: var(--amber);
  font-variant-numeric: tabular-nums;
}

/* ---------- 正文容器 ---------- */
.prose {
  width: min(40rem, 100%);
  font-size: var(--fs-17);
  line-height: 1.75;
}

.prose > * + * { margin-top: 1.1em; }
.prose h2 { font-family: var(--font-display); font-size: var(--fs-28); line-height: 1.25; margin-top: 1.9em; }
.prose h3 { font-family: var(--font-display); font-size: var(--fs-21); line-height: 1.35; margin-top: 1.6em; }
.prose ul, .prose ol { padding-left: 1.3em; }
.prose ul { list-style: none; }
.prose ul > li { position: relative; }
.prose ul > li::before {
  content: "";
  position: absolute;
  left: -1.1em;
  top: .78em;
  width: 6px;
  height: 1px;
  background: var(--amber);
}
.prose ol { list-style: decimal; }
.prose a {
  color: var(--blue-deep);
  text-decoration: underline;
  text-underline-offset: .2em;
}
.prose a:hover { color: var(--blue); }
.prose code {
  font-family: var(--font-mono);
  font-size: .92em;
  background: rgba(198, 207, 214, .35);
  padding: .1em .35em;
  border-radius: 2px;
}

.prose--dark { color: var(--silver-soft); }
.prose--dark h2, .prose--dark h3 { color: var(--white); }
.prose--dark a { color: var(--focus); }
.prose--dark code { background: rgba(150, 162, 171, .18); }

/* ---------- 注释 / 刻度线 ---------- */
.note {
  font-size: 13px;
  line-height: 1.65;
  color: var(--blue-deep);
  border-left: 2px solid var(--rule);
  padding-left: .75rem;
}

.note--dark {
  color: var(--silver);
  border-left-color: rgba(150, 162, 171, .42);
}

.rule-scale {
  display: block;
  height: 8px;
  border-top: 1px solid var(--rule);
  color: var(--rule);
  background-image: repeating-linear-gradient(to right, currentColor 0 1px, transparent 1px 24px);
  background-size: auto 4px;
  background-repeat: repeat-x;
  background-position: top left;
}

.rule-scale--dark {
  border-top-color: rgba(150, 162, 171, .40);
  color: rgba(150, 162, 171, .55);
}

/* ---------- 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: .5rem;
  font-family: var(--font-display);
  font-size: var(--fs-14);
  font-weight: 700;
  letter-spacing: .05em;
  padding: .62rem 1.15rem;
  border: 1px solid transparent;
  border-radius: 2px;
  text-decoration: none;
  white-space: nowrap;
  transition:
    background-color var(--dur-1) var(--ease),
    color var(--dur-1) var(--ease),
    border-color var(--dur-1) var(--ease),
    transform var(--dur-1) var(--ease),
    box-shadow var(--dur-2) var(--ease);
}

.btn--primary {
  background-color: var(--blue);
  color: var(--white);
  border-color: var(--blue);
}

.btn--primary:hover {
  background-color: var(--blue-deep);
  border-color: var(--blue-deep);
  transform: translateY(-2px);
  box-shadow: var(--shadow-2);
}

.btn--ghost {
  background-color: transparent;
  color: var(--silver-soft);
  border-color: rgba(150, 162, 171, .50);
}

.btn--ghost:hover {
  color: var(--white);
  border-color: var(--silver);
  background-color: rgba(150, 162, 171, .12);
  transform: translateY(-2px);
}

.btn--outline {
  background-color: transparent;
  color: var(--ink);
  border-color: var(--rule);
}

.btn--outline:hover {
  color: var(--blue-deep);
  border-color: var(--blue);
  transform: translateY(-2px);
  box-shadow: var(--shadow-1);
}

.btn--compact {
  padding: .46rem .85rem;
  font-size: var(--fs-12);
  letter-spacing: .07em;
}

/* ---------- 标签 ---------- */
.chip {
  display: inline-flex;
  align-items: center;
  gap: .35rem;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  line-height: 1.5;
  padding: .16rem .5rem;
  border: 1px solid currentColor;
  border-radius: 2px;
  letter-spacing: .04em;
  white-space: nowrap;
}

.chip--amber { color: var(--amber); }
.chip--blue { color: var(--blue); }
.chip--orange { color: var(--orange-deep); }
.chip--silver { color: var(--silver); }

/* ---------- 卡片 ---------- */
.card {
  position: relative;
  background-color: var(--white);
  border: 1px solid var(--rule);
  border-radius: var(--radius-sm);
  transition: border-color var(--dur-1) var(--ease), box-shadow var(--dur-2) var(--ease), transform var(--dur-1) var(--ease);
}

.card:hover {
  border-color: var(--blue);
  box-shadow: var(--shadow-1);
  transform: translateY(-2px);
}

.card--ink {
  background-color: var(--ink-2);
  border-color: rgba(150, 162, 171, .30);
  color: var(--white);
}

.card--ink:hover { border-color: var(--blue); }

.card__head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 1rem;
  padding: 1rem 1.15rem;
  border-bottom: 1px solid var(--rule);
}

.card--ink .card__head { border-bottom-color: rgba(150, 162, 171, .28); }

.card__body { padding: 1.15rem; }

.card__foot {
  padding: .8rem 1.15rem;
  border-top: 1px solid var(--rule);
  background-color: rgba(198, 207, 214, .24);
  font-size: var(--fs-14);
}

.card--ink .card__foot {
  border-top-color: rgba(150, 162, 171, .28);
  background-color: rgba(150, 162, 171, .08);
  color: var(--silver-soft);
}

/* ---------- 面包屑 ---------- */
.breadcrumbs {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: .45rem;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: .04em;
  color: var(--blue-deep);
}

.breadcrumbs a { text-decoration: none; }
.breadcrumbs a:hover { text-decoration: underline; text-underline-offset: .2em; }
.breadcrumbs__sep { color: var(--silver); }
.breadcrumbs--dark { color: var(--silver); }
.breadcrumbs--dark .breadcrumbs__sep { color: rgba(150, 162, 171, .7); }

/* ---------- 图片容器（页面阶段复用） ---------- */
.media-frame {
  position: relative;
  display: block;
  overflow: hidden;
  background-color: var(--ink-2);
  border: 1px solid var(--rule);
  border-radius: var(--radius-sm);
}

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

.media-frame--16x9 { aspect-ratio: 16 / 9; }
.media-frame--4x3 { aspect-ratio: 4 / 3; }
.media-frame--1x1 { aspect-ratio: 1 / 1; }
.media-frame--3x4 { aspect-ratio: 3 / 4; }

.media-frame--empty {
  background-image: repeating-linear-gradient(
    135deg,
    rgba(150, 162, 171, .16) 0 1px,
    transparent 1px 12px
  );
}

.media-frame__caption {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  padding: .55rem .75rem;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  line-height: 1.5;
  letter-spacing: .03em;
  color: var(--white);
  background-image: linear-gradient(to top, rgba(12, 17, 22, .90), rgba(12, 17, 22, 0));
}

.media-frame__tag {
  position: absolute;
  top: .6rem;
  left: .6rem;
  padding: .16rem .45rem;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  line-height: 1.5;
  color: var(--ink);
  background-color: var(--amber);
  border-radius: 2px;
}

/* ==========================================================================
   头部
   ========================================================================== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 60;
  color: var(--white);
  background-color: var(--ink);
  background-image: linear-gradient(to right, rgba(150, 162, 171, .10) 1px, transparent 1px);
  background-size: 80px 100%;
  border-bottom: 1px solid rgba(150, 162, 171, .30);
}

.header-inner {
  width: var(--shell);
  margin-inline: auto;
  min-height: var(--header-h);
  display: flex;
  align-items: center;
  gap: clamp(.75rem, 2vw, 2rem);
}

.brand-block {
  display: flex;
  align-items: center;
  gap: .7rem;
  min-width: 0;
}

.brand-mark {
  display: inline-flex;
  align-items: center;
  gap: .6rem;
  padding: .3rem 0;
  color: var(--white);
  text-decoration: none;
}

.brand-mark__sigil {
  flex: none;
  width: 12px;
  height: 12px;
  border-radius: 1px;
  background-color: var(--amber);
  box-shadow: 0 0 0 1px rgba(214, 154, 45, .40), 0 0 0 4px rgba(214, 154, 45, .12);
  transition: box-shadow var(--dur-2) var(--ease);
}

.brand-mark:hover .brand-mark__sigil {
  box-shadow: 0 0 0 1px rgba(214, 154, 45, .95), 0 0 0 6px rgba(214, 154, 45, .18);
}

.brand-mark__text {
  display: flex;
  flex-direction: column;
  line-height: 1.15;
  min-width: 0;
}

.brand-mark__name {
  font-family: var(--font-display);
  font-weight: 900;
  font-size: var(--fs-17);
  letter-spacing: -.01em;
  white-space: nowrap;
}

.brand-mark__sub {
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: .06em;
  color: var(--silver);
  white-space: nowrap;
}

.version-badge {
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: .02em;
  color: var(--silver-soft);
  border: 1px solid rgba(150, 162, 171, .42);
  border-left: 2px solid var(--amber);
  border-radius: 2px;
  padding: .2rem .5rem;
  white-space: nowrap;
}

/* --- 导航 --- */
.site-nav { margin-left: auto; }

.site-nav__list {
  display: flex;
  align-items: center;
  gap: clamp(.15rem, 1.1vw, 1.15rem);
}

.site-nav__item { display: block; }

.site-nav__link {
  position: relative;
  display: inline-block;
  padding: .55rem .3rem;
  font-size: var(--fs-14);
  font-weight: 500;
  color: var(--silver-soft);
  text-decoration: none;
  white-space: nowrap;
  transition: color var(--dur-1) var(--ease);
}

.site-nav__link::after {
  content: "";
  position: absolute;
  left: .3rem;
  right: .3rem;
  bottom: .22rem;
  height: 1px;
  background-color: var(--blue);
  transform: scaleX(0);
  transform-origin: left center;
  transition: transform var(--dur-2) var(--ease), background-color var(--dur-1) var(--ease);
}

.site-nav__link:hover { color: var(--white); }
.site-nav__link:hover::after { transform: scaleX(1); }

.site-nav__link[aria-current="page"] { color: var(--white); }
.site-nav__link[aria-current="page"]::after {
  transform: scaleX(1);
  background-color: var(--amber);
}

/* --- 头部右侧操作 --- */
.header-actions {
  display: flex;
  align-items: center;
  gap: .55rem;
  flex: none;
}

.announce-toggle {
  display: inline-flex;
  align-items: center;
  gap: .45rem;
  padding: .44rem .6rem;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: .04em;
  color: var(--silver-soft);
  border: 1px solid rgba(150, 162, 171, .34);
  border-radius: 2px;
  transition: color var(--dur-1) var(--ease), border-color var(--dur-1) var(--ease), background-color var(--dur-1) var(--ease);
}

.announce-toggle:hover {
  color: var(--white);
  border-color: var(--silver);
  background-color: rgba(150, 162, 171, .10);
}

.announce-toggle[aria-expanded="true"] {
  color: var(--white);
  border-color: var(--amber);
  background-color: rgba(214, 154, 45, .12);
}

.announce-toggle__dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background-color: var(--amber);
}

/* --- 更新公告浮层 --- */
.announce-panel {
  position: absolute;
  top: calc(100% + 1px);
  right: max(1.5rem, calc((100% - 1240px) / 2));
  width: min(340px, calc(100% - 2rem));
  z-index: 8;
  padding: 1rem 1.1rem 1.15rem;
  background-color: var(--ink-2);
  border: 1px solid rgba(150, 162, 171, .34);
  border-left: 3px solid var(--amber);
  border-radius: 0 0 var(--radius-sm) var(--radius-sm);
  box-shadow: var(--shadow-2);
}

.announce-panel:not([hidden]) {
  animation: panel-in var(--dur-2) var(--ease) both;
}

@keyframes panel-in {
  from { opacity: 0; transform: translateY(-6px); }
  to { opacity: 1; transform: none; }
}

.announce-panel__head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: .6rem;
}

.announce-panel__close {
  width: 24px;
  height: 24px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 18px;
  line-height: 1;
  color: var(--silver);
  border-radius: 2px;
  transition: color var(--dur-1) var(--ease), background-color var(--dur-1) var(--ease);
}

.announce-panel__close:hover {
  color: var(--white);
  background-color: rgba(150, 162, 171, .18);
}

.announce-panel__text {
  font-size: var(--fs-14);
  line-height: 1.7;
  color: var(--silver-soft);
}

.announce-panel__link {
  display: inline-block;
  margin-top: .85rem;
  padding-bottom: 1px;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: .04em;
  color: var(--focus);
  border-bottom: 1px solid rgba(127, 211, 240, .45);
  transition: color var(--dur-1) var(--ease), border-color var(--dur-1) var(--ease);
}

.announce-panel__link:hover {
  color: var(--white);
  border-bottom-color: var(--white);
}

/* --- 滚动进度 --- */
.scroll-progress {
  position: absolute;
  left: 0;
  right: 0;
  bottom: -1px;
  height: 2px;
  background-color: rgba(150, 162, 171, .18);
  pointer-events: none;
}

.scroll-progress__bar {
  display: block;
  width: 100%;
  height: 100%;
  transform: scaleX(0);
  transform-origin: 0 50%;
  background-image: linear-gradient(90deg, var(--blue) 0%, var(--blue) 72%, var(--amber) 100%);
  will-change: transform;
}

/* --- 移动菜单按钮 --- */
.nav-toggle {
  display: none;
  align-items: center;
  gap: .5rem;
  padding: .44rem .6rem;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: .04em;
  color: var(--silver-soft);
  border: 1px solid rgba(150, 162, 171, .34);
  border-radius: 2px;
  transition: color var(--dur-1) var(--ease), border-color var(--dur-1) var(--ease);
}

.nav-toggle:hover { color: var(--white); border-color: var(--silver); }

.nav-toggle__bars {
  position: relative;
  width: 18px;
  height: 2px;
  border-radius: 1px;
  background-color: currentColor;
  transition: background-color var(--dur-1) var(--ease);
}

.nav-toggle__bars::before,
.nav-toggle__bars::after {
  content: "";
  position: absolute;
  left: 0;
  width: 18px;
  height: 2px;
  border-radius: 1px;
  background-color: currentColor;
  transition: transform var(--dur-2) var(--ease), top var(--dur-2) var(--ease);
}

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

.nav-toggle[aria-expanded="true"] .nav-toggle__bars { background-color: transparent; }
.nav-toggle[aria-expanded="true"] .nav-toggle__bars::before { top: 0; transform: rotate(45deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle__bars::after { top: 0; transform: rotate(-45deg); }

/* ==========================================================================
   页脚
   ========================================================================== */
.site-footer {
  position: relative;
  background-color: var(--ink);
  color: var(--silver-soft);
  border-top: 1px solid rgba(150, 162, 171, .30);
  padding-block: clamp(2.5rem, 5vw, 4.25rem) 1.5rem;
}

.site-footer::before {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background-image: linear-gradient(to right, rgba(150, 162, 171, .07) 1px, transparent 1px);
  background-size: 80px 100%;
}

.footer-inner {
  position: relative;
  width: var(--shell);
  margin-inline: auto;
}

.footer-top {
  display: grid;
  grid-template-columns: minmax(0, 1.1fr) minmax(0, 1.6fr);
  gap: clamp(2rem, 4vw, 4rem);
  padding-bottom: clamp(1.75rem, 3.5vw, 3rem);
  border-bottom: 1px solid rgba(150, 162, 171, .22);
}

.footer-brand__mark {
  font-family: var(--font-display);
  font-weight: 900;
  font-size: var(--fs-21);
  letter-spacing: -.01em;
  color: var(--white);
}

.footer-brand__meta {
  margin-top: .55rem;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: .03em;
  color: var(--silver);
}

.footer-brand__commit {
  margin-top: .85rem;
  font-size: var(--fs-14);
  line-height: 1.7;
  color: var(--silver-soft);
  max-width: 24em;
}

.footer-brand .rule-scale { margin-top: 1.4rem; }

.footer-nav {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1.5rem;
}

.footer-col__title {
  font-family: var(--font-display);
  font-size: var(--fs-12);
  font-weight: 700;
  letter-spacing: .2em;
  color: var(--amber);
  margin-bottom: .9rem;
}

.footer-col__list li + li { margin-top: .55rem; }

.footer-col__list a {
  font-size: var(--fs-14);
  color: var(--silver-soft);
  border-bottom: 1px solid transparent;
  transition: color var(--dur-1) var(--ease), border-color var(--dur-1) var(--ease);
}

.footer-col__list a:hover {
  color: var(--white);
  border-bottom-color: var(--amber);
}

.footer-contact {
  display: flex;
  flex-wrap: wrap;
  gap: .7rem 2rem;
  padding-block: 1.4rem;
  border-bottom: 1px solid rgba(150, 162, 171, .18);
  font-size: var(--fs-14);
  color: var(--silver-soft);
}

.footer-contact__item {
  display: inline-flex;
  align-items: baseline;
  gap: .5rem;
}

.footer-contact__key {
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: .08em;
  color: var(--amber);
}

.footer-bottom {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: .5rem 1.5rem;
  padding-top: 1.25rem;
}

.footer-legal {
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: .03em;
  color: var(--silver);
}

.footer-legal--muted { color: rgba(150, 162, 171, .75); }

/* ==========================================================================
   显现动效
   ========================================================================== */
.js-on [data-reveal] {
  opacity: 0;
  transform: translateY(10px);
  transition: opacity 320ms var(--ease), transform 320ms var(--ease);
}

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

/* ==========================================================================
   响应式
   ========================================================================== */
@media (max-width: 1180px) {
  :root { --shell: min(1240px, 100% - 2rem); }
  .site-nav__list { gap: .3rem; }
  .header-cta { display: none; }
}

@media (max-width: 980px) {
  .version-badge { display: none; }

  .site-nav {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    margin-left: 0;
    max-height: 0;
    overflow: hidden;
    visibility: hidden;
    background-color: var(--ink-2);
    border-bottom: 1px solid rgba(150, 162, 171, .30);
    transition: max-height var(--dur-2) var(--ease), visibility var(--dur-2) linear;
  }

  .site-nav[data-open="true"] {
    max-height: 26rem;
    visibility: visible;
  }

  .site-nav__list {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    width: var(--shell);
    margin-inline: auto;
    padding: .4rem 0 1rem;
  }

  .site-nav__link {
    display: block;
    padding: .85rem .1rem;
    font-size: var(--fs-17);
    border-bottom: 1px solid rgba(150, 162, 171, .16);
  }

  .site-nav__link::after { display: none; }
  .site-nav__link[aria-current="page"] { color: var(--amber); }

  .nav-toggle { display: inline-flex; }
  .header-inner { gap: .5rem; }

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

@media (max-width: 900px) {
  .grid--62,
  .grid--58 { grid-template-columns: minmax(0, 1fr); }
}

@media (max-width: 640px) {
  :root {
    --shell: calc(100% - 2rem);
    --shell-narrow: calc(100% - 2rem);
    --header-h: 62px;
    --fs-17: 1rem;
    --fs-21: 1.1875rem;
    --fs-28: 1.5rem;
    --fs-40: 2rem;
    --fs-64: 2.75rem;
  }

  .brand-mark__sub { display: none; }
  .announce-toggle__label { display: none; }
  .nav-toggle__label { display: none; }

  .announce-panel { right: 1rem; }

  .grid--2,
  .grid--3 { grid-template-columns: minmax(0, 1fr); }

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

/* ==========================================================================
   降低动效偏好
   ========================================================================== */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: .01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .01ms !important;
  }

  .js-on [data-reveal] {
    opacity: 1 !important;
    transform: none !important;
  }

  .announce-panel:not([hidden]) { animation: none; }
  .site-nav { transition: none; }

  .btn:hover,
  .card:hover { transform: none !important; }
}