/* ============================================================
   量化 · AI · 工程 · 企业官网风设计系统（主站 / 文章页共享规范）
   藏青 + 品牌蓝 · 白底浅灰交替 · 线性图标 · 无 webfont
   ============================================================ */

/* ---------- 设计变量 ---------- */
:root {
  --navy: #0A2540;            /* 页脚、数据带、深色区块 */
  --navy-2: #0E3158;
  --brand: #1B66FF;           /* 品牌蓝 */
  --brand-dark: #154DD1;
  --brand-soft: #EDF3FF;      /* 图标底、浅蓝背景 */
  --ink: #0F1F33;             /* 标题 */
  --text: #3D4A5C;            /* 正文 */
  --muted: #7A8699;           /* 次级 */
  --bg: #FFFFFF;
  --bg-soft: #F5F8FC;         /* 区块交替背景 */
  --line: #E3E9F2;            /* 边框 */
  --radius: 12px;
  --shadow: 0 12px 32px rgba(15, 31, 51, .10);
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", "微软雅黑", "Noto Sans SC", sans-serif;
  --font-mono: Consolas, "SF Mono", "JetBrains Mono", Menlo, Monaco, "Courier New", monospace;
  --header-h: 64px;
}

/* ---------- 基础 ---------- */
* { box-sizing: border-box; }

html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-h) + 16px);
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  padding-top: var(--header-h);
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.75;
  color: var(--text);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

h1, h2, h3, h4, p, ul, ol { margin: 0; }
ul, ol { padding: 0; list-style: none; }
a { color: var(--brand); }
img, svg { display: block; }
button { font-family: inherit; cursor: pointer; }
::selection { background: var(--brand-soft); color: var(--ink); }

a:focus-visible, button:focus-visible {
  outline: 2px solid var(--brand);
  outline-offset: 2px;
  border-radius: 4px;
}

[id] { scroll-margin-top: calc(var(--header-h) + 12px); }

/* ---------- 工具类 ---------- */
.container { max-width: 1200px; margin: 0 auto; }
.mono { font-family: var(--font-mono); }

.icon { width: 24px; height: 24px; flex: none; }
.li-arrow { width: 16px; height: 16px; flex: none; margin-top: 5px; color: var(--brand); }

/* ---------- 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 24px;
  border-radius: 8px;
  font-size: 15px;
  font-weight: 600;
  line-height: 1.4;
  text-decoration: none;
  border: 1.5px solid transparent;
  transition: transform .2s ease, background-color .2s ease, border-color .2s ease,
    color .2s ease, box-shadow .2s ease;
}

.btn-primary {
  background: var(--brand);
  color: #fff;
}
.btn-primary:hover {
  background: var(--brand-dark);
  transform: translateY(-1px);
  box-shadow: 0 8px 20px rgba(27, 102, 255, .28);
}

.btn-secondary {
  background: #fff;
  color: var(--ink);
  border-color: var(--line);
}
.btn-secondary:hover {
  border-color: var(--brand);
  color: var(--brand);
  transform: translateY(-1px);
}

.btn-invert {
  background: #fff;
  color: var(--brand);
}
.btn-invert:hover {
  color: var(--brand-dark);
  transform: translateY(-1px);
  box-shadow: 0 8px 24px rgba(0, 0, 0, .25);
}

.btn-sm { padding: 8px 16px; font-size: 13.5px; }

.text-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: var(--brand);
  font-weight: 600;
  font-size: 15px;
  text-decoration: none;
}
.text-link:hover { color: var(--brand-dark); text-decoration: underline; }
.text-link .li-arrow { margin-top: 0; }

/* ---------- 顶部导航 ---------- */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--header-h);
  background: #fff;
  border-bottom: 1px solid var(--line);
  z-index: 100;
  transition: box-shadow .25s ease;
}
.site-header.scrolled { box-shadow: 0 4px 16px rgba(15, 31, 51, .08); }

.nav-inner {
  max-width: 1200px;
  margin: 0 auto;
  height: var(--header-h);
  padding: 0 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: var(--ink);
  font-weight: 700;
  font-size: 17px;
  letter-spacing: .01em;
}
.brand-mark {
  width: 36px;
  height: 36px;
  border-radius: 8px;
  flex: none;
}
span.brand-mark {
  background: var(--navy);
  color: #fff;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 14px;
  font-weight: 800;
  letter-spacing: .04em;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 28px;
}
.nav-links a {
  color: var(--muted);
  text-decoration: none;
  font-size: 14.5px;
  font-weight: 500;
  transition: color .2s ease;
}
.nav-links a:hover,
.nav-links a.active { color: var(--ink); }

.nav-cta { padding: 9px 20px; font-size: 14px; }

.nav-toggle {
  display: none;
  width: 40px;
  height: 40px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fff;
  color: var(--ink);
  align-items: center;
  justify-content: center;
}
.nav-toggle .icon { width: 20px; height: 20px; }
.nav-toggle .icon-close { display: none; }
.nav-open .nav-toggle .icon-menu { display: none; }
.nav-open .nav-toggle .icon-close { display: block; }

/* 移动端下拉面板 */
.mobile-panel {
  display: none;
  position: fixed;
  top: var(--header-h);
  left: 0;
  right: 0;
  z-index: 99;
  background: #fff;
  border-bottom: 1px solid var(--line);
  box-shadow: 0 20px 40px rgba(15, 31, 51, .10);
  padding: 6px 24px 22px;
}
.nav-open .mobile-panel { display: block; }
.mobile-panel nav { display: flex; flex-direction: column; }
.mobile-panel a {
  padding: 13px 4px;
  color: var(--ink);
  text-decoration: none;
  font-size: 15px;
  font-weight: 500;
  border-bottom: 1px solid var(--line);
}
.mobile-panel a.btn {
  margin-top: 16px;
  border-bottom: none;
  justify-content: center;
}

/* ---------- Hero ---------- */
.hero {
  position: relative;
  padding: 104px 24px 96px;
  text-align: center;
  overflow: hidden;
  background:
    radial-gradient(640px 420px at 86% -4%, rgba(27, 102, 255, .09), transparent 70%),
    linear-gradient(rgba(15, 31, 51, .03) 1px, transparent 1px),
    linear-gradient(90deg, rgba(15, 31, 51, .03) 1px, transparent 1px),
    linear-gradient(180deg, #FFFFFF 0%, var(--bg-soft) 100%);
  background-size: auto, 40px 40px, 40px 40px, auto;
}

.hero-inner { max-width: 860px; margin: 0 auto; }

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 7px 16px;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 999px;
  font-size: 13px;
  font-weight: 500;
  color: var(--muted);
}
.hero-badge .dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: #22A06B;
  flex: none;
}

.hero-title { margin-top: 28px; }
.hero-name {
  display: block;
  font-size: clamp(40px, 6vw, 56px);
  font-weight: 800;
  color: var(--ink);
  line-height: 1.18;
  letter-spacing: -.01em;
}
.hero-line2 {
  display: block;
  margin-top: 14px;
  font-size: clamp(24px, 3.4vw, 34px);
  font-weight: 700;
  color: var(--ink);
  line-height: 1.35;
}
.hero-line2 em {
  font-style: normal;
  color: var(--brand);
}

.hero-intro {
  max-width: 720px;
  margin: 24px auto 0;
  font-size: 16.5px;
  color: var(--muted);
}

.hero-titles {
  margin-top: 18px;
  font-size: 14px;
  color: var(--muted);
  letter-spacing: .02em;
}

.hero-cta {
  margin-top: 36px;
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 14px;
}

/* ---------- 数据带（stats band） ---------- */
.stats-band {
  background: var(--navy);
  padding: 56px 24px;
}
.stats-grid {
  max-width: 1200px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: repeat(6, 1fr);
}
.stat {
  padding: 4px 18px;
  text-align: center;
  border-left: 1px solid rgba(255, 255, 255, .12);
}
.stat:first-child { border-left: none; }
.stat-num {
  font-family: var(--font-mono);
  font-size: clamp(26px, 2.8vw, 38px);
  font-weight: 700;
  color: #fff;
  line-height: 1.15;
  white-space: nowrap;
}
.stat-suffix {
  font-size: .55em;
  color: rgba(255, 255, 255, .85);
  margin-left: 2px;
  font-family: var(--font-sans);
  font-weight: 600;
}
.stat-label {
  margin-top: 10px;
  font-size: 13px;
  color: rgba(255, 255, 255, .65);
  line-height: 1.5;
}

/* ---------- 区块与标题模式 ---------- */
.section { padding: 88px 24px; }
.section.alt { background: var(--bg-soft); }

.section-head {
  text-align: center;
  margin-bottom: 48px;
}
.eyebrow {
  font-size: 13px;
  font-weight: 700;
  color: var(--brand);
  letter-spacing: .2em;
  text-transform: uppercase;
  margin-bottom: 12px;
}
.section-head h2 {
  font-size: clamp(30px, 4vw, 40px);
  font-weight: 800;
  color: var(--ink);
  line-height: 1.25;
  letter-spacing: -.01em;
}
.section-sub {
  max-width: 720px;
  margin: 14px auto 0;
  font-size: 16px;
  color: var(--muted);
}
.section-more {
  margin-top: 14px;
}
.section-more .text-link {
  font-size: 13.5px;
}
.section-more .li-arrow {
  width: 14px;
  height: 14px;
  margin-top: 0;
  transition: transform .2s ease;
}
.section-more .text-link:hover .li-arrow { transform: translateX(2px); }

/* ---------- 卡片 / 图标容器 / 芯片 ---------- */
.card {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 28px;
  transition: transform .25s ease, box-shadow .25s ease, border-color .25s ease;
}
.card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow);
  border-color: #C9D8F5;
}

.icon-box {
  width: 48px;
  height: 48px;
  border-radius: 10px;
  background: var(--brand-soft);
  color: var(--brand);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 18px;
}
.icon-box .icon { width: 24px; height: 24px; }

.chip {
  display: inline-block;
  padding: 3px 10px;
  background: #F1F5FA;
  border: 1px solid var(--line);
  border-radius: 6px;
  font-size: 12px;
  line-height: 1.6;
  color: var(--muted);
  white-space: nowrap;
}
.tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 18px;
}

.points { display: grid; gap: 9px; margin-top: 16px; }
.points li {
  display: flex;
  align-items: flex-start;
  gap: 9px;
  font-size: 14.5px;
  line-height: 1.65;
  color: var(--text);
}

/* ---------- 卡片通用：小徽章 / 可点标题 / 文末文章链接 ---------- */
.mini-badge {
  display: inline-block;
  padding: 2px 10px;
  border-radius: 999px;
  border: 1px solid #D6E4FF;
  background: var(--brand-soft);
  color: var(--brand);
  font-size: 12px;
  font-weight: 600;
  line-height: 1.7;
  white-space: nowrap;
}

a.card-title {
  color: inherit;
  text-decoration: none;
  transition: color .2s ease;
}
a.card-title:hover { color: var(--brand); }
a.card-title:focus-visible { outline-offset: 4px; }

.card-cta {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  margin-top: 18px;
  font-size: 14px;
}
.card-cta .li-arrow {
  width: 14px;
  height: 14px;
  margin-top: 0;
  transition: transform .2s ease;
}
.card-cta:hover .li-arrow { transform: translateX(2px); }

/* ---------- 核心优势 ---------- */
.strengths-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}
.strength-card h3 {
  font-size: 18px;
  font-weight: 700;
  color: var(--ink);
}
.strength-card p {
  margin-top: 10px;
  font-size: 15px;
  color: var(--text);
}

/* ---------- 量化交易体系 ---------- */
.quant-highlights {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
  margin-bottom: 56px;
}
.metric-card {
  position: relative;
  overflow: hidden;
}
.metric-card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: var(--brand);
}
.metric-num {
  font-family: var(--font-mono);
  font-size: clamp(24px, 2.4vw, 32px);
  font-weight: 700;
  color: var(--navy);
  line-height: 1.2;
  white-space: nowrap;
}
.metric-label {
  margin-top: 10px;
  font-size: 15px;
  font-weight: 600;
  color: var(--ink);
}
.metric-note {
  margin-top: 4px;
  font-size: 13px;
  color: var(--muted);
}

.quant-projects { display: grid; gap: 20px; }
.proj-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 6px 16px;
}
.proj-head h3 {
  font-size: 18px;
  font-weight: 700;
  color: var(--ink);
}
.proj-role {
  font-size: 13px;
  font-weight: 600;
  color: var(--brand);
  white-space: nowrap;
}
.proj-head-meta {
  display: inline-flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 8px 10px;
}
.proj-head-meta .proj-role { white-space: normal; }
.proj-desc {
  margin-top: 10px;
  font-size: 15px;
  color: var(--text);
}

/* ---------- AI 技能生态 ---------- */
.ai-metrics {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 10px 0;
  margin-bottom: 48px;
}
.ai-metric {
  padding: 18px 12px;
  text-align: center;
  border-left: 1px solid var(--line);
}
.ai-metric:first-child { border-left: none; }
.ai-metric .num {
  font-family: var(--font-mono);
  font-size: clamp(24px, 2.6vw, 32px);
  font-weight: 700;
  color: var(--navy);
  line-height: 1.2;
  white-space: nowrap;
}
.ai-metric .label {
  margin-top: 6px;
  font-size: 13px;
  color: var(--muted);
}

.ai-flagships {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  margin-bottom: 24px;
}
.flagship-card h3 {
  font-size: 17px;
  font-weight: 700;
  color: var(--brand);
  line-height: 1.45;
}
.flagship-card a.card-title:hover { color: var(--brand-dark); }
.flagship-card p {
  margin-top: 10px;
  font-size: 14.5px;
  color: var(--text);
}

.cat-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 14px 24px;
}
.cat-item {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 16px 20px;
  transition: transform .25s ease, box-shadow .25s ease, border-color .25s ease;
}
.cat-item:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow);
  border-color: #C9D8F5;
}
.cat-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}
.cat-name {
  font-size: 15px;
  font-weight: 600;
  color: var(--ink);
}
.cat-count {
  flex: none;
  min-width: 28px;
  padding: 1px 9px;
  border-radius: 999px;
  background: var(--brand-soft);
  color: var(--brand);
  font-family: var(--font-mono);
  font-size: 12.5px;
  font-weight: 700;
  text-align: center;
}
.cat-egs {
  margin-top: 6px;
  font-family: var(--font-mono);
  font-size: 12.5px;
  color: var(--muted);
  line-height: 1.6;
  word-break: break-all;
}

/* ---------- 专利技术方案 ---------- */
.patents-lead {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 40px;
  margin-bottom: 48px;
}
.patents-note {
  max-width: 640px;
  font-size: 15px;
  color: var(--muted);
}
.patents-big {
  flex: none;
  display: flex;
  align-items: baseline;
  gap: 8px;
  font-family: var(--font-mono);
}
.patents-big .num {
  font-size: clamp(56px, 7vw, 76px);
  font-weight: 800;
  color: var(--navy);
  line-height: 1;
  letter-spacing: -.02em;
}
.patents-big .unit {
  font-family: var(--font-sans);
  font-size: 20px;
  font-weight: 700;
  color: var(--muted);
}

.patents-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}
.patent-card:last-child { grid-column: 1 / -1; }
.patent-card h3 {
  font-size: 18px;
  font-weight: 700;
  color: var(--ink);
}
.patent-range {
  margin-top: 2px;
  font-size: 13px;
  font-weight: 600;
  color: var(--brand);
  font-family: var(--font-mono);
}
.patent-card .patent-desc {
  margin-top: 10px;
  font-size: 14.5px;
  color: var(--text);
}
.patent-card .icon-box { margin-bottom: 14px; }

/* ---------- 著作 ---------- */
.books-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}
.book-card {
  position: relative;
  padding-left: 32px;
}
.book-card::before {
  content: "";
  position: absolute;
  left: 0;
  top: 24px;
  bottom: 24px;
  width: 4px;
  border-radius: 2px;
  background: var(--brand);
}
.book-name {
  font-size: 22px;
  font-weight: 800;
  color: var(--ink);
  line-height: 1.4;
}
.book-meta {
  margin-top: 6px;
  font-size: 13px;
  color: var(--muted);
}
.book-desc {
  margin-top: 14px;
  font-size: 15px;
  color: var(--text);
}
.book-method {
  margin-top: 18px;
  padding: 12px 16px;
  background: var(--brand-soft);
  border-radius: 8px;
  font-size: 13.5px;
  line-height: 1.7;
  color: var(--brand-dark);
}

/* ---------- 作品与下载 ---------- */
.downloads-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}
.dl-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}
.dl-kind-novel {
  background: rgba(10, 37, 64, .07);
  color: var(--navy);
  border-color: #DCE4EE;
}
.dl-size {
  flex: none;
  font-family: var(--font-mono);
  font-size: 12.5px;
  color: var(--muted);
}
.dl-card h3 {
  margin-top: 14px;
  font-size: 17px;
  font-weight: 700;
  color: var(--ink);
  line-height: 1.5;
}
.dl-desc {
  margin-top: 10px;
  font-size: 14px;
  color: var(--text);
}
.dl-actions {
  margin-top: 18px;
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 12px 18px;
}
.dl-note {
  margin-top: 36px;
  text-align: center;
  font-size: 13px;
  color: var(--muted);
}

/* ---------- 工程项目 ---------- */
.projects-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}
.project-card { position: relative; }
.project-card h3 {
  font-size: 18px;
  font-weight: 700;
  color: var(--ink);
  line-height: 1.5;
  padding-right: 84px;
}
.type-badge {
  position: absolute;
  top: 24px;
  right: 24px;
  padding: 2px 10px;
  border-radius: 999px;
  border: 1px solid transparent;
  font-size: 12px;
  font-weight: 600;
  line-height: 1.7;
  white-space: nowrap;
}
.badge-row {
  position: absolute;
  top: 24px;
  right: 24px;
  display: flex;
  align-items: flex-start;
  gap: 8px;
}
.badge-row .type-badge { position: static; }
.type-blue {
  background: var(--brand-soft);
  color: var(--brand);
  border-color: #D6E4FF;
}
.type-navy {
  background: rgba(10, 37, 64, .07);
  color: var(--navy);
  border-color: #DCE4EE;
}
.type-gray {
  background: #F1F4F8;
  color: var(--muted);
  border-color: var(--line);
}
.proj-role-card {
  margin-top: 4px;
  font-size: 13px;
  font-weight: 600;
  color: var(--brand);
}
.project-card .proj-desc {
  margin-top: 10px;
  font-size: 14.5px;
}
.project-card .points li { font-size: 14px; }
.project-card .tags { margin-top: 16px; }

/* ---------- 文章与动态 ---------- */
.posts-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}
.post-card {
  display: block;
  text-decoration: none;
}
.post-date {
  font-size: 12.5px;
  color: var(--muted);
  letter-spacing: .04em;
}
.post-card h3 {
  margin-top: 10px;
  font-size: 18px;
  font-weight: 700;
  color: var(--ink);
  line-height: 1.5;
  transition: color .2s ease;
}
.post-card:hover h3 { color: var(--brand); }
.post-summary {
  margin-top: 10px;
  font-size: 14px;
  color: var(--text);
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}
.post-card .tags { margin-top: 16px; }

.posts-more-wrap {
  margin-top: 40px;
  text-align: center;
}

.posts-fallback h3 {
  font-size: 17px;
  font-weight: 700;
  color: var(--ink);
}
.posts-fallback p {
  margin-top: 10px;
  font-size: 14.5px;
  color: var(--muted);
}
.posts-fallback .text-link { margin-top: 16px; }

/* ---------- CTA 横幅 ---------- */
.cta-wrap { padding: 0 24px; }
.cta-banner {
  position: relative;
  overflow: hidden;
  max-width: 1200px;
  margin: 0 auto;
  padding: 64px 32px;
  border-radius: 16px;
  background: radial-gradient(560px 300px at 88% 0%, rgba(27, 102, 255, .28), transparent 70%), var(--navy);
  text-align: center;
  color: #fff;
}
.cta-banner h2 {
  font-size: clamp(24px, 3.2vw, 34px);
  font-weight: 800;
  line-height: 1.35;
  color: #fff;
}
.cta-banner p {
  max-width: 640px;
  margin: 14px auto 0;
  font-size: 15.5px;
  color: rgba(255, 255, 255, .72);
}
.cta-banner .btn { margin-top: 28px; }

/* ---------- 联系 ---------- */
.contact-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}
.contact-card {
  display: flex;
  align-items: center;
  gap: 16px;
  text-decoration: none;
}
.contact-card .icon-box { margin-bottom: 0; }
.contact-label {
  display: block;
  font-size: 13px;
  color: var(--muted);
}
.contact-value {
  display: block;
  margin-top: 2px;
  font-size: 15px;
  font-weight: 600;
  color: var(--ink);
  word-break: normal;
  overflow-wrap: anywhere;
  transition: color .2s ease;
}
a.contact-card:hover .contact-value { color: var(--brand); }

/* ---------- 页脚 ---------- */
.footer {
  background: var(--navy);
  color: rgba(255, 255, 255, .65);
}
.footer-grid {
  max-width: 1200px;
  margin: 0 auto;
  padding: 64px 24px 48px;
  display: grid;
  grid-template-columns: 1.8fr 1fr 1fr 1.4fr;
  gap: 40px;
}
.footer h4 {
  margin-bottom: 18px;
  font-size: 14px;
  font-weight: 700;
  color: #fff;
  letter-spacing: .06em;
}
.footer-brand .brand { color: #fff; }
.footer-brand .footer-tagline {
  margin-top: 16px;
  font-size: 13.5px;
  line-height: 1.8;
  max-width: 300px;
}
.footer-brand .footer-domain {
  display: inline-block;
  margin-top: 12px;
  font-family: var(--font-mono);
  font-size: 13px;
  color: rgba(255, 255, 255, .45);
}
.footer-links { display: grid; gap: 10px; }
.footer-links a,
.footer-links span {
  color: rgba(255, 255, 255, .65);
  text-decoration: none;
  font-size: 14px;
  line-height: 1.6;
  transition: color .2s ease;
}
.footer-links a:hover { color: #fff; }
.footer-links .flabel {
  color: rgba(255, 255, 255, .45);
  margin-right: 8px;
  font-size: 13px;
}
.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, .12);
  padding: 20px 24px;
  text-align: center;
  font-size: 13px;
  color: rgba(255, 255, 255, .45);
}

/* ---------- 滚动渐入动画 ----------
   opacity:0 只在 <html> 带 js 类（main.js 启动时添加）时生效，
   JS 失败 / 被禁用时内容始终可见可点。 */
.reveal.visible {
  animation: fadeUp .55s cubic-bezier(.22, .61, .36, 1) both;
}
html.js .reveal { opacity: 0; }
html.js .reveal.revealed,
.revealed { opacity: 1; }
@keyframes fadeUp {
  from { opacity: 0; transform: translateY(18px); }
}

/* ---------- 响应式 ---------- */
@media (max-width: 1024px) {
  .strengths-grid,
  .ai-flagships,
  .projects-grid,
  .downloads-grid { grid-template-columns: repeat(2, 1fr); }
  .quant-highlights { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 900px) {
  .nav-links, .nav-cta { display: none; }
  .nav-toggle { display: inline-flex; }

  .books-grid,
  .patents-grid { grid-template-columns: 1fr; }
  .patent-card:last-child { grid-column: auto; }

  .posts-grid { grid-template-columns: 1fr; }
  .contact-grid { grid-template-columns: repeat(2, 1fr); }

  .footer-grid { grid-template-columns: repeat(2, 1fr); gap: 36px; }

  .ai-metrics { grid-template-columns: repeat(2, 1fr); }
  .ai-metric:nth-child(3) { border-left: none; }
  .ai-metric:nth-child(n+3) { border-top: 1px solid var(--line); }

  .patents-lead {
    flex-direction: column-reverse;
    align-items: flex-start;
    gap: 20px;
    margin-bottom: 40px;
  }
}

@media (max-width: 680px) {
  .section { padding: 64px 20px; }
  .hero { padding: 72px 20px 64px; }

  .stats-grid { grid-template-columns: repeat(2, 1fr); gap: 28px 0; }
  .stat { border-left: none; padding: 0 14px; }
  .stat:nth-child(even) { border-left: 1px solid rgba(255, 255, 255, .12); }

  .cat-grid { grid-template-columns: 1fr; }

  .downloads-grid { grid-template-columns: 1fr; }

  .cta-banner { padding: 48px 24px; }
}

@media (max-width: 560px) {
  .strengths-grid,
  .ai-flagships,
  .projects-grid,
  .quant-highlights,
  .quant-projects,
  .contact-grid { grid-template-columns: 1fr; }

  .project-card h3 { padding-right: 0; }
  .type-badge,
  .badge-row {
    position: static;
    display: inline-flex;
    flex-wrap: wrap;
    margin-bottom: 12px;
  }
  .footer-grid { grid-template-columns: 1fr; gap: 32px; }
  .hero-cta .btn { width: 100%; max-width: 320px; }
}

/* ---------- 降低动效 ---------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: .01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .01ms !important;
  }
  html.js .reveal { opacity: 1; }
  .reveal.visible { animation: none; }
}