/* =========================================================
   必搏登录 · 全站共享样式 /assets/site.css
   结构：reset → 变量 → 基础排版 → 布局 → 组件 → 头部 → 页脚 → 响应式
   ========================================================= */

*, *::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 { margin: 0; }
ul, ol { padding: 0; list-style: none; }
img, svg, video, canvas { display: block; max-width: 100%; }
button { font: inherit; color: inherit; background: none; border: 0; cursor: pointer; }
a { color: inherit; text-decoration: none; }
table { border-collapse: collapse; width: 100%; }

:where(a, button, summary, [tabindex]):focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 3px;
  border-radius: 3px;
}

/* ---------- 变量 ---------- */
:root {
  --sea-900: #061A31;
  --sea-800: #0A2B4E;
  --ink: #0E1620;
  --paper: #F4F7FA;
  --graphite: #2B3A4A;
  --steel: #6B8299;
  --cyan: #00E5C7;
  --cyan-soft: #6FE9DC;
  --orange: #FF7A45;

  --rail-w: 272px;
  --bar-h: 60px;
  --wrap: 1180px;

  --radius-s: 6px;
  --radius-m: 14px;
  --radius-l: 26px;

  --line-dark: rgba(244, 247, 250, 0.14);
  --line-light: rgba(10, 43, 78, 0.14);
  --glass-dark: rgba(244, 247, 250, 0.07);

  --font-display: Inter, "Helvetica Neue", Arial, "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;
  --font-body: "PingFang SC", "Microsoft YaHei", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  --font-mono: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, "Courier New", monospace;

  --ease: cubic-bezier(0.22, 0.61, 0.36, 1);
  --shadow-1: 0 22px 48px -30px rgba(6, 26, 49, 0.65);
}

/* ---------- 基础排版 ---------- */
body {
  background: var(--paper);
  color: var(--graphite);
  font-family: var(--font-body);
  font-size: 17px;
  line-height: 1.8;
  min-height: 100vh;
  overflow-x: hidden;
}

.display {
  font-family: var(--font-display);
  font-weight: 300;
  font-size: clamp(2.4rem, 6vw, 5.5rem);
  line-height: 1.05;
  letter-spacing: -0.02em;
  color: var(--sea-800);
}
.section--dark .display,
.section--deep .display { color: var(--paper); }

.h2 {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: clamp(1.55rem, 3vw, 2.5rem);
  line-height: 1.2;
  letter-spacing: -0.01em;
  color: var(--sea-800);
}
.section--dark .h2,
.section--deep .h2,
.panel--dark .h2,
.tile--dark .h2 { color: var(--paper); }

.h3 {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: clamp(1.1rem, 1.6vw, 1.35rem);
  line-height: 1.35;
  color: var(--sea-800);
}
.section--dark .h3,
.section--deep .h3 { color: var(--paper); }

.lead {
  font-size: clamp(1rem, 1.3vw, 1.15rem);
  line-height: 1.75;
  color: var(--steel);
}
.section--dark .lead,
.section--deep .lead { color: rgba(244, 247, 250, 0.74); }

.eyebrow {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--steel);
}
.section--dark .eyebrow,
.section--deep .eyebrow,
.tile--dark .eyebrow,
.tile--glass .eyebrow,
.panel--dark .eyebrow { color: var(--cyan-soft); }

.index {
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--steel);
}

.is-cyan { color: var(--cyan); }

.prose { max-width: 68ch; }
.prose p { font-size: 17px; line-height: 1.85; }
.prose p + p { margin-top: 1rem; }
.prose h3 { margin-top: 1.8rem; }

/* ---------- 布局 ---------- */
.wrap {
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding-inline: clamp(1.1rem, 4vw, 2.6rem);
}

.section {
  position: relative;
  padding-block: clamp(3.2rem, 7vw, 6.5rem);
}
.section--paper { background: var(--paper); }
.section--dark { background: var(--sea-800); color: var(--paper); }
.section--deep { background: var(--sea-900); color: var(--paper); }
.section--glass {
  background:
    radial-gradient(120% 90% at 8% 0%, rgba(0, 229, 199, 0.12), transparent 60%),
    linear-gradient(180deg, var(--sea-800), var(--sea-900));
  color: var(--paper);
}

.page-main { display: block; }
#main-content { scroll-margin-top: calc(var(--bar-h) + 1rem); }

.stack { display: grid; gap: clamp(0.9rem, 2vw, 1.5rem); }
.cluster { display: flex; flex-wrap: wrap; gap: 0.7rem 1rem; align-items: center; }
.grid-2 { display: grid; gap: clamp(1rem, 2.4vw, 1.8rem); grid-template-columns: 1fr; }
.grid-3 { display: grid; gap: clamp(1rem, 2.4vw, 1.8rem); grid-template-columns: 1fr; }

@media (min-width: 768px) {
  .grid-2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .grid-3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
}

.divider {
  height: 1px;
  border: 0;
  width: 100%;
  background: linear-gradient(90deg, var(--cyan), rgba(0, 229, 199, 0) 70%);
}
.divider--light { background: linear-gradient(90deg, rgba(10, 43, 78, 0.35), rgba(10, 43, 78, 0) 70%); }

/* ---------- 版块头 ---------- */
.section-head {
  display: grid;
  gap: 0.7rem;
  max-width: 62ch;
  margin-bottom: clamp(1.4rem, 3vw, 2.4rem);
}
.section-head__index {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--cyan);
}
.section--paper .section-head__index { color: var(--sea-800); }
.section-head__title { font-family: var(--font-display); font-weight: 600; font-size: clamp(1.5rem, 3vw, 2.4rem); line-height: 1.2; color: var(--sea-800); }
.section--dark .section-head__title,
.section--deep .section-head__title { color: var(--paper); }
.section-head__lead { color: var(--steel); font-size: 16px; }
.section--dark .section-head__lead,
.section--deep .section-head__lead { color: rgba(244, 247, 250, 0.72); }

/* ---------- 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.45rem;
  padding: 0.72rem 1.2rem;
  border: 1px solid transparent;
  border-radius: 999px;
  font-family: var(--font-display);
  font-size: 14px;
  font-weight: 600;
  letter-spacing: 0.02em;
  line-height: 1.2;
  text-align: center;
  transition: background 0.2s var(--ease), color 0.2s var(--ease),
              border-color 0.2s var(--ease), transform 0.2s var(--ease);
}
.btn:hover { transform: translateY(-1px); }
.btn--primary { background: var(--cyan); color: var(--sea-900); }
.btn--primary:hover { background: var(--cyan-soft); }
.btn--ghost { background: transparent; color: var(--paper); border-color: rgba(244, 247, 250, 0.32); }
.btn--ghost:hover { border-color: var(--cyan); color: var(--cyan); }
.btn--accent { background: var(--orange); color: #341405; }
.btn--accent:hover { background: #ff8f63; }
.btn--outline { background: transparent; color: var(--sea-800); border-color: rgba(10, 43, 78, 0.3); }
.btn--outline:hover { border-color: var(--sea-800); background: rgba(10, 43, 78, 0.06); }
.btn--sm { padding: 0.5rem 0.9rem; font-size: 12.5px; }

/* ---------- 小元素 ---------- */
.chip {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.28rem 0.7rem;
  border-radius: 999px;
  background: rgba(0, 229, 199, 0.14);
  border: 1px solid rgba(0, 229, 199, 0.42);
  color: var(--sea-800);
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}
.section--dark .chip,
.section--deep .chip { color: var(--cyan-soft); }

.tag {
  display: inline-flex;
  align-items: center;
  padding: 0.22rem 0.62rem;
  border-radius: var(--radius-s);
  background: rgba(10, 43, 78, 0.08);
  color: var(--sea-800);
  font-size: 12.5px;
  letter-spacing: 0.04em;
}
.tag--accent { background: rgba(255, 122, 69, 0.16); color: #A83F14; }

/* ---------- 内容层 ---------- */
.bento-grid {
  display: grid;
  gap: clamp(0.85rem, 2vw, 1.4rem);
  grid-template-columns: repeat(2, minmax(0, 1fr));
}
@media (min-width: 768px) { .bento-grid { grid-template-columns: repeat(4, minmax(0, 1fr)); } }
@media (min-width: 1200px) { .bento-grid { grid-template-columns: repeat(6, minmax(0, 1fr)); } }

.bento-cell { grid-column: span 2; }
.bento-cell--wide { grid-column: span 2; }
@media (min-width: 768px) { .bento-cell--wide { grid-column: span 4; } }
@media (min-width: 768px) { .bento-cell--tall { grid-row: span 2; } }

.tile {
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
  min-height: 100%;
  padding: clamp(1rem, 2.4vw, 1.7rem);
  border-radius: var(--radius-m);
  background: #ffffff;
  box-shadow: var(--shadow-1);
}
.tile__label {
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--steel);
}
.tile__title { font-family: var(--font-display); font-weight: 600; font-size: 1.15rem; line-height: 1.3; color: var(--sea-800); }
.tile__body { font-size: 15.5px; color: var(--graphite); }
.tile--glass {
  background: var(--glass-dark);
  border: 1px solid rgba(244, 247, 250, 0.18);
  -webkit-backdrop-filter: blur(14px);
  backdrop-filter: blur(14px);
  color: var(--paper);
  box-shadow: none;
}
.tile--glass .tile__title { color: var(--paper); }
.tile--glass .tile__label { color: var(--cyan-soft); }
.tile--glass .tile__body { color: rgba(244, 247, 250, 0.78); }
.tile--dark { background: var(--sea-800); color: var(--paper); box-shadow: none; }
.tile--dark .tile__title { color: var(--paper); }
.tile--dark .tile__label { color: var(--cyan-soft); }
.tile--dark .tile__body { color: rgba(244, 247, 250, 0.78); }
.tile--accent {
  background: linear-gradient(155deg, rgba(0, 229, 199, 0.2), rgba(10, 43, 78, 0.94) 72%);
  border: 1px solid rgba(0, 229, 199, 0.38);
  color: var(--paper);
  box-shadow: none;
}
.tile--accent .tile__title { color: var(--paper); }
.tile--accent .tile__label { color: var(--cyan-soft); }
.tile--accent .tile__body { color: rgba(244, 247, 250, 0.82); }

.panel {
  padding: clamp(1.2rem, 3vw, 2.2rem);
  border-radius: var(--radius-l);
  background: #ffffff;
}
.panel--glass {
  background: rgba(244, 247, 250, 0.07);
  border: 1px solid rgba(244, 247, 250, 0.16);
  -webkit-backdrop-filter: blur(16px);
  backdrop-filter: blur(16px);
  color: var(--paper);
}
.panel--dark { background: var(--sea-900); color: var(--paper); }

/* ---------- 数据 ---------- */
.stat { display: grid; gap: 0.3rem; }
.stat__num {
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(2.2rem, 5vw, 3.6rem);
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--cyan);
}
.stat__unit { font-size: 0.45em; font-weight: 600; margin-left: 0.15em; color: var(--cyan-soft); }
.stat__label { font-size: 13.5px; color: var(--steel); letter-spacing: 0.02em; }
.section--paper .stat__num { color: var(--sea-800); }

/* ---------- 图形位 ---------- */
.figure { margin: 0; display: grid; gap: 0.7rem; }
.figure__media {
  position: relative;
  display: grid;
  place-items: center;
  width: 100%;
  aspect-ratio: 16 / 9;
  overflow: hidden;
  border-radius: var(--radius-m);
  background:
    radial-gradient(90% 80% at 20% 10%, rgba(0, 229, 199, 0.18), transparent 62%),
    linear-gradient(150deg, var(--sea-800), var(--sea-900));
}
.figure__media img,
.figure__media svg { width: 100%; height: 100%; object-fit: cover; }
.figure__caption { font-size: 12.5px; letter-spacing: 0.02em; color: var(--steel); }
.figure--21x9 .figure__media { aspect-ratio: 21 / 9; }
.figure--4x3 .figure__media { aspect-ratio: 4 / 3; }
.figure--3x2 .figure__media { aspect-ratio: 3 / 2; }
.figure--1x1 .figure__media { aspect-ratio: 1 / 1; }

/* ---------- 面包屑 ---------- */
.breadcrumb {
  padding-block: 1rem 0;
  font-size: 12.5px;
  letter-spacing: 0.04em;
  color: var(--steel);
}
.breadcrumb ol { display: flex; flex-wrap: wrap; align-items: center; gap: 0.35rem; }
.breadcrumb li { display: inline-flex; align-items: center; }
.breadcrumb li + li::before { content: "/"; margin-right: 0.35rem; color: rgba(107, 130, 153, 0.65); }
.breadcrumb a:hover { color: var(--cyan); }
.section--dark .breadcrumb a:hover { color: var(--cyan); }

/* ---------- CTA 带 ---------- */
.cta-band {
  position: relative;
  overflow: hidden;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 1.2rem;
  padding: clamp(1.5rem, 4vw, 3rem);
  border-radius: var(--radius-l);
  background:
    radial-gradient(90% 120% at 100% 0%, rgba(255, 122, 69, 0.22), transparent 62%),
    var(--sea-800);
  color: var(--paper);
}

/* =========================================================
   头部
   ========================================================= */
.skip-link {
  position: fixed;
  top: 0.5rem;
  left: 0.5rem;
  z-index: 120;
  padding: 0.6rem 1rem;
  border-radius: var(--radius-s);
  background: var(--cyan);
  color: var(--sea-900);
  font-size: 13px;
  font-weight: 700;
  transform: translateY(-180%);
  transition: transform 0.2s var(--ease);
}
.skip-link:focus { transform: none; }

.site-header { position: relative; z-index: 80; }

/* 移动端顶栏 */
.header-bar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--bar-h);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding-inline: clamp(0.9rem, 4vw, 1.4rem);
  background: rgba(6, 26, 49, 0.94);
  border-bottom: 1px solid var(--line-dark);
  -webkit-backdrop-filter: blur(12px);
  backdrop-filter: blur(12px);
  z-index: 85;
}
.header-bar::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -1px;
  width: 72px;
  height: 2px;
  background: var(--cyan);
}

.brand { display: inline-flex; align-items: center; gap: 0.6rem; color: var(--paper); }
.brand__mark { color: var(--cyan); display: grid; place-items: center; }
.brand__wordmark {
  display: flex;
  flex-direction: column;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 1rem;
  line-height: 1.15;
  letter-spacing: 0.02em;
}
.brand__line {
  font-family: var(--font-mono);
  font-size: 9.5px;
  font-weight: 400;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--cyan-soft);
}

.nav-toggle {
  display: inline-flex;
  align-items: center;
  gap: 0.55rem;
  padding: 0.5rem 0.85rem;
  border: 1px solid rgba(244, 247, 250, 0.26);
  border-radius: 999px;
  color: var(--paper);
  font-size: 12px;
  letter-spacing: 0.14em;
  transition: border-color 0.2s var(--ease), background 0.2s var(--ease);
}
.nav-toggle:hover { border-color: var(--cyan); background: rgba(0, 229, 199, 0.1); }
.nav-toggle__bars { display: grid; gap: 4px; width: 16px; }
.nav-toggle__bars i {
  display: block;
  height: 1.5px;
  background: currentColor;
  transition: transform 0.2s var(--ease), opacity 0.2s var(--ease);
}
.site-header[data-open="true"] .nav-toggle__bars i:nth-child(1) { transform: translateY(5.5px) rotate(45deg); }
.site-header[data-open="true"] .nav-toggle__bars i:nth-child(2) { opacity: 0; }
.site-header[data-open="true"] .nav-toggle__bars i:nth-child(3) { transform: translateY(-5.5px) rotate(-45deg); }

/* 抽屉 / 左框架栏 */
.header-rail {
  position: fixed;
  top: 0;
  bottom: 0;
  left: 0;
  z-index: 80;
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
  width: min(86vw, 340px);
  padding: calc(var(--bar-h) + 1.3rem) 1.3rem 2rem;
  overflow-y: auto;
  background: linear-gradient(180deg, var(--sea-900), var(--sea-800) 62%, var(--sea-900));
  border-right: 1px solid rgba(244, 247, 250, 0.1);
  transform: translateX(-101%);
  transition: transform 0.28s var(--ease);
}
.site-header[data-open="true"] .header-rail { transform: none; }
body.is-nav-open { overflow: hidden; }
body.is-nav-open::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: 75;
  background: rgba(6, 26, 49, 0.6);
  -webkit-backdrop-filter: blur(2px);
  backdrop-filter: blur(2px);
}

.rail-brand { display: grid; gap: 0.3rem; color: var(--paper); }
.rail-brand__index {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--cyan);
}
.rail-brand__name {
  font-family: var(--font-display);
  font-weight: 300;
  font-size: clamp(1.5rem, 2.2vw, 1.8rem);
  line-height: 1.1;
  letter-spacing: -0.01em;
}
.rail-brand__line { font-size: 12.5px; letter-spacing: 0.04em; color: rgba(244, 247, 250, 0.6); }

.rail-switch { display: grid; gap: 0.45rem; }
.rail-switch__label {
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: rgba(244, 247, 250, 0.5);
}
.rail-switch__track {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.25rem;
  padding: 0.25rem;
  border: 1px solid rgba(244, 247, 250, 0.16);
  border-radius: 999px;
  background: rgba(244, 247, 250, 0.06);
}
.rail-switch__btn {
  padding: 0.42rem 0.5rem;
  border-radius: 999px;
  color: rgba(244, 247, 250, 0.72);
  font-size: 13px;
  letter-spacing: 0.06em;
  transition: background 0.2s var(--ease), color 0.2s var(--ease);
}
.rail-switch__btn:hover { color: var(--paper); }
.rail-switch__btn.is-active {
  background: var(--cyan);
  color: var(--sea-900);
  font-weight: 600;
}

.rail-nav { display: grid; gap: 0.7rem; }
.rail-nav__caption {
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: rgba(244, 247, 250, 0.5);
}
.rail-nav__list { display: grid; gap: 0.18rem; }
.rail-nav__link {
  display: grid;
  grid-template-columns: 2.1rem 1fr;
  align-items: center;
  gap: 0.35rem;
  padding: 0.55rem 0.7rem;
  border-left: 2px solid transparent;
  border-radius: 0 10px 10px 0;
  color: rgba(244, 247, 250, 0.74);
  font-size: 14.5px;
  transition: background 0.2s var(--ease), color 0.2s var(--ease), border-color 0.2s var(--ease);
}
.rail-nav__idx {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: rgba(244, 247, 250, 0.42);
  transition: color 0.2s var(--ease);
}
.rail-nav__link:hover { background: rgba(244, 247, 250, 0.07); color: var(--paper); }
.rail-nav__link:hover .rail-nav__idx { color: var(--cyan-soft); }
.rail-nav__link[aria-current="page"] {
  background: rgba(0, 229, 199, 0.12);
  border-left-color: var(--cyan);
  color: var(--paper);
}
.rail-nav__link[aria-current="page"] .rail-nav__idx { color: var(--cyan); }

.rail-actions { display: grid; gap: 0.55rem; margin-top: auto; }
.rail-actions .btn { width: 100%; }
.rail-foot {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: rgba(244, 247, 250, 0.32);
}

/* 阅读进度 */
.scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  z-index: 95;
  background: rgba(10, 43, 78, 0.16);
  pointer-events: none;
}
.scroll-progress__bar {
  display: block;
  width: 0;
  height: 100%;
  background: linear-gradient(90deg, var(--cyan), var(--cyan-soft) 62%, var(--orange));
  transition: width 0.12s linear;
}

/* =========================================================
   页脚
   ========================================================= */
.site-footer {
  position: relative;
  overflow: hidden;
  background: var(--ink);
  color: var(--paper);
  border-top: 1px solid rgba(0, 229, 199, 0.3);
}
.site-footer::before {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  height: 300px;
  pointer-events: none;
  background:
    radial-gradient(110% 90% at 10% 0%, rgba(0, 229, 199, 0.14), transparent 62%),
    radial-gradient(80% 70% at 92% 0%, rgba(255, 122, 69, 0.1), transparent 60%);
}

.footer-inner {
  position: relative;
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding: clamp(2.6rem, 6vw, 4.6rem) clamp(1.1rem, 4vw, 2.6rem) 1.6rem;
}

.footer-head {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-end;
  justify-content: space-between;
  gap: 1rem 2rem;
  padding-bottom: 1.6rem;
  border-bottom: 1px solid var(--line-dark);
}
.footer-brand {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.75rem;
  font-family: var(--font-display);
  font-weight: 300;
  font-size: clamp(1.45rem, 3.4vw, 2.4rem);
  line-height: 1.1;
  letter-spacing: -0.01em;
}
.footer-brand__dot {
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--cyan);
  box-shadow: 0 0 0 5px rgba(0, 229, 199, 0.16);
}
.footer-tagline {
  max-width: 44ch;
  font-size: 14px;
  line-height: 1.7;
  color: var(--steel);
}

.footer-grid {
  display: grid;
  gap: clamp(1.6rem, 4vw, 3rem);
  grid-template-columns: 1fr;
  padding-block: clamp(1.8rem, 4vw, 2.8rem);
}
@media (min-width: 640px) { .footer-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); } }
@media (min-width: 1024px) { .footer-grid { grid-template-columns: 1.5fr 1fr 1fr; } }

.footer-col { display: grid; align-content: start; gap: 0.5rem; }
.footer-col__title {
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 400;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--cyan-soft);
  margin-bottom: 0.4rem;
}

.footer-links { display: grid; gap: 0.5rem; }
.footer-links__item { display: block; }
.footer-links a {
  display: inline-flex;
  align-items: center;
  gap: 0.55rem;
  padding-block: 0.15rem;
  color: rgba(244, 247, 250, 0.78);
  font-size: 14.5px;
  transition: color 0.2s var(--ease);
}
.footer-links a::before {
  content: "";
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: rgba(0, 229, 199, 0.45);
  transition: background 0.2s var(--ease);
}
.footer-links a:hover { color: var(--cyan); }
.footer-links a:hover::before { background: var(--orange); }

.footer-contact { display: grid; gap: 0.85rem; }
.footer-contact__item { display: grid; gap: 0.15rem; }
.footer-contact__label {
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--steel);
}
.footer-contact__value {
  font-family: var(--font-mono);
  font-size: 14px;
  line-height: 1.6;
  color: var(--paper);
  word-break: break-word;
}
.footer-note { margin-top: 0.4rem; font-size: 13px; line-height: 1.7; color: var(--steel); }

.footer-bottom {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 0.8rem 1.4rem;
  padding-top: 1.4rem;
  border-top: 1px solid rgba(244, 247, 250, 0.12);
}
.footer-copy { font-size: 12.5px; color: var(--steel); letter-spacing: 0.02em; }
.footer-legal { display: flex; flex-wrap: wrap; gap: 0.5rem 1.2rem; font-size: 12.5px; }
.footer-icp { font-family: var(--font-mono); letter-spacing: 0.06em; color: var(--steel); }

/* =========================================================
   工具类与状态
   ========================================================= */
.to-top {
  position: fixed;
  right: clamp(0.9rem, 3vw, 1.7rem);
  bottom: clamp(0.9rem, 3vw, 1.7rem);
  z-index: 70;
  display: grid;
  place-items: center;
  width: 46px;
  height: 46px;
  border-radius: 50%;
  border: 1px solid rgba(0, 229, 199, 0.42);
  background: var(--sea-800);
  color: var(--cyan);
  opacity: 0;
  visibility: hidden;
  transform: translateY(10px);
  transition: opacity 0.25s var(--ease), transform 0.25s var(--ease), visibility 0.25s;
}
.to-top.is-visible { opacity: 1; visibility: visible; transform: none; }
.to-top:hover { background: var(--sea-900); }

html[data-reveal-ready] [data-reveal] {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity 0.55s var(--ease), transform 0.55s var(--ease);
}
html[data-reveal-ready] [data-reveal].is-in { opacity: 1; transform: none; }

/* ---------- 桌面：左栏成为页面边框 ---------- */
@media (min-width: 1024px) {
  body { padding-left: var(--rail-w); padding-top: 0; }
  .header-bar { display: none; }
  .nav-toggle { display: none; }
  .header-rail {
    width: var(--rail-w);
    transform: none;
    padding: 2.4rem 1.5rem 1.8rem;
    box-shadow: 1px 0 0 rgba(0, 229, 199, 0.12) inset;
  }
  .header-rail::after {
    content: "";
    position: absolute;
    top: 0;
    right: -1px;
    width: 2px;
    height: 88px;
    background: linear-gradient(180deg, var(--cyan), rgba(0, 229, 199, 0));
  }
  .scroll-progress { left: var(--rail-w); }
  #main-content { scroll-margin-top: 1.5rem; }
}

/* ---------- 手机 / 平板 ---------- */
@media (max-width: 1023.98px) {
  body { padding-top: var(--bar-h); }
  .scroll-progress { top: 0; }
}

@media (max-width: 420px) {
  .brand__line { display: none; }
  .nav-toggle__label { display: none; }
}

/* ---------- 动效偏好 ---------- */
@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;
  }
  html[data-reveal-ready] [data-reveal] { opacity: 1; transform: none; }
  .btn:hover { transform: none; }
}

/* ---------- 打印 ---------- */
@media print {
  .site-header, .to-top, .scroll-progress { display: none; }
  body { padding: 0; background: #fff; color: #000; }
}