:root {
  --bg: #ffffff;
  --bg-alt: #f8fafc;
  --text: #0f172a;
  --text-2: #475569;
  --text-3: #94a3b8;
  --border: #e2e8f0;
  --accent: #2563eb;
  --accent-soft: #eff6ff;
  --radius: 16px;
  --shadow-sm: 0 1px 2px rgba(15, 23, 42, 0.04);
  --shadow-md: 0 12px 32px -12px rgba(15, 23, 42, 0.12);
  --container: 1080px;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: 76px;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

.container {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 24px;
}

/* ---------- 导航 ---------- */

.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid transparent;
  transition: border-color 0.25s, box-shadow 0.25s;
}

.nav.scrolled {
  border-bottom-color: var(--border);
  box-shadow: var(--shadow-sm);
}

.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 20px;
  font-weight: 700;
  color: var(--text);
  text-decoration: none;
  letter-spacing: 0.5px;
}

.brand i {
  color: var(--accent);
  font-style: normal;
}

.brand-icon {
  width: 22px;
  height: 22px;
  color: var(--accent);
}

.nav-menu {
  display: flex;
  gap: 32px;
}

.nav-menu a {
  color: var(--text-2);
  text-decoration: none;
  font-size: 15px;
  font-weight: 500;
  transition: color 0.2s;
}

.nav-menu a:hover {
  color: var(--accent);
}

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  padding: 8px;
  cursor: pointer;
}

.nav-toggle span {
  width: 22px;
  height: 2px;
  background: var(--text);
  border-radius: 2px;
  transition: transform 0.25s, opacity 0.25s;
}

.nav-toggle.open span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.nav-toggle.open span:nth-child(2) {
  opacity: 0;
}

.nav-toggle.open span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* ---------- Hero ---------- */

.hero {
  position: relative;
  padding: 168px 0 96px;
  overflow: hidden;
  text-align: center;
}

.hero::before,
.hero::after {
  content: "";
  position: absolute;
  border-radius: 50%;
  filter: blur(90px);
  pointer-events: none;
}

.hero::before {
  width: 480px;
  height: 480px;
  background: rgba(37, 99, 235, 0.1);
  top: -180px;
  right: -120px;
}

.hero::after {
  width: 420px;
  height: 420px;
  background: rgba(14, 165, 233, 0.08);
  bottom: -200px;
  left: -140px;
}

.hero .container {
  position: relative;
  z-index: 1;
}

.hero-eyebrow {
  display: inline-block;
  font-size: 14px;
  font-weight: 600;
  color: var(--accent);
  background: var(--accent-soft);
  border: 1px solid #dbeafe;
  border-radius: 999px;
  padding: 6px 16px;
  margin-bottom: 24px;
}

.hero h1 {
  font-size: clamp(34px, 6vw, 56px);
  line-height: 1.25;
  font-weight: 800;
  letter-spacing: -0.02em;
}

.hero h1 em {
  font-style: normal;
  color: var(--accent);
}

.hero-sub {
  max-width: 560px;
  margin: 20px auto 0;
  font-size: 17px;
  color: var(--text-2);
}

.hero-actions {
  display: flex;
  justify-content: center;
  gap: 16px;
  margin-top: 36px;
}

.btn {
  display: inline-block;
  padding: 12px 28px;
  border-radius: 12px;
  font-size: 15px;
  font-weight: 600;
  text-decoration: none;
  transition: transform 0.2s, box-shadow 0.2s, background 0.2s, border-color 0.2s;
}

.btn-primary {
  background: var(--accent);
  color: #fff;
  box-shadow: 0 8px 20px -8px rgba(37, 99, 235, 0.5);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 12px 24px -8px rgba(37, 99, 235, 0.55);
}

.btn-ghost {
  color: var(--text);
  border: 1px solid var(--border);
  background: #fff;
}

.btn-ghost:hover {
  border-color: var(--text-3);
  transform: translateY(-2px);
}

.hero-stats {
  display: flex;
  justify-content: center;
  gap: clamp(32px, 8vw, 80px);
  list-style: none;
  margin-top: 64px;
}

.hero-stats li {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.hero-stats strong {
  font-size: 32px;
  font-weight: 800;
  color: var(--text);
}

.hero-stats span {
  font-size: 14px;
  color: var(--text-3);
}

/* ---------- 通用 Section ---------- */

.section {
  padding: 96px 0;
}

.section-alt {
  background: var(--bg-alt);
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}

.section-head {
  text-align: center;
  max-width: 560px;
  margin: 0 auto 56px;
}

.section-eyebrow {
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 8px;
}

.section-head h2 {
  font-size: clamp(26px, 4vw, 36px);
  font-weight: 800;
  letter-spacing: -0.01em;
}

.section-desc {
  margin-top: 12px;
  color: var(--text-2);
  font-size: 16px;
}

/* ---------- 项目卡片 ---------- */

.card {
  position: relative;
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px;
  box-shadow: var(--shadow-sm);
  transition: transform 0.25s, box-shadow 0.25s, border-color 0.25s;
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
  border-color: #cbd5e1;
}

.card-featured {
  margin-bottom: 24px;
  padding: 36px;
  background: linear-gradient(135deg, #ffffff 0%, #f0f9ff 100%);
  border-color: #bae6fd;
}

.card-featured:hover {
  border-color: #7dd3fc;
}

.card-head {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-bottom: 16px;
}

.card-icon {
  flex-shrink: 0;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 56px;
  height: 56px;
  border-radius: 14px;
  background: var(--tint, var(--accent-soft));
  color: var(--color, var(--accent));
}

.card-icon svg {
  width: 28px;
  height: 28px;
}

.card-head h3 {
  font-size: 20px;
  font-weight: 700;
}

.card-badges {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 6px;
}

.badge {
  display: inline-block;
  font-size: 12px;
  font-weight: 600;
  color: var(--text-2);
  background: var(--bg-alt);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 2px 10px;
}

.badge-hot {
  color: #fff;
  background: linear-gradient(135deg, #0284c7, #2563eb);
  border-color: transparent;
}

.badge-soon {
  color: #b45309;
  background: #fffbeb;
  border-color: #fde68a;
}

.badge-ok {
  color: #15803d;
  background: #f0fdf4;
  border-color: #bbf7d0;
}

.card-desc {
  color: var(--text-2);
  font-size: 15px;
}

.card-feats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 10px 24px;
  list-style: none;
  margin: 20px 0 4px;
}

.card-feats li {
  position: relative;
  padding-left: 20px;
  font-size: 14px;
  color: var(--text-2);
}

.card-feats li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 9px;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: #0284c7;
  opacity: 0.7;
}

.card-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 20px;
}

.card-tags span {
  font-size: 12px;
  font-weight: 500;
  color: var(--text-2);
  background: var(--bg-alt);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 3px 10px;
}

.card-actions {
  display: flex;
  gap: 12px;
  margin-top: 20px;
}

.card-btn {
  display: inline-block;
  padding: 8px 20px;
  border-radius: 10px;
  border: 1px solid #0284c7;
  color: #0284c7;
  font-size: 14px;
  font-weight: 600;
  text-decoration: none;
  transition: background 0.2s, color 0.2s;
}

.card-btn.primary {
  background: #0284c7;
  color: #fff;
}

.card-btn.primary:hover {
  background: #0369a1;
  border-color: #0369a1;
}

.card-btn:hover {
  background: #0284c7;
  color: #fff;
}

/* 卡片整体可点击（详情页入口） */

.card-stretch {
  position: absolute;
  inset: 0;
  z-index: 1;
  border-radius: var(--radius);
}

.card-actions,
.footer-links {
  position: relative;
  z-index: 2;
}

.card-hint {
  display: block;
  margin-top: 16px;
  font-size: 13px;
  font-weight: 600;
  color: var(--accent);
}

.card:hover .card-hint {
  text-decoration: underline;
}

/* ---------- 项目详情页 ---------- */

.detail-hero {
  padding: 148px 0 56px;
  border-bottom: 1px solid var(--border);
  background: linear-gradient(180deg, #f8fafc 0%, #ffffff 100%);
}

.detail-hero-top {
  display: flex;
  align-items: center;
  gap: 20px;
  flex-wrap: wrap;
}

.detail-hero-top .card-icon {
  width: 72px;
  height: 72px;
  border-radius: 18px;
}

.detail-hero-top .card-icon svg {
  width: 36px;
  height: 36px;
}

.detail-hero h1 {
  font-size: clamp(28px, 4.5vw, 40px);
  font-weight: 800;
  letter-spacing: -0.01em;
}

.detail-hero .card-badges {
  margin-top: 8px;
}

.detail-intro {
  max-width: 720px;
  margin-top: 24px;
  font-size: 17px;
  color: var(--text-2);
}

.detail-section {
  padding: 56px 0;
}

.detail-section h2 {
  font-size: 22px;
  font-weight: 800;
  margin-bottom: 24px;
  padding-left: 14px;
  border-left: 4px solid var(--accent);
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
}

.feature-item {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px 24px;
  box-shadow: var(--shadow-sm);
}

.feature-item strong {
  display: block;
  font-size: 16px;
  margin-bottom: 6px;
}

.feature-item p {
  font-size: 14px;
  color: var(--text-2);
}

.detail-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 12px;
  max-width: 820px;
}

.detail-list li {
  position: relative;
  padding-left: 24px;
  color: var(--text-2);
  font-size: 15px;
}

.detail-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 10px;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--accent);
  opacity: 0.65;
}

.detail-list li strong {
  color: var(--text);
}

.back-link {
  display: inline-block;
  margin-top: 8px;
  color: var(--accent);
  font-size: 15px;
  font-weight: 600;
  text-decoration: none;
}

.back-link:hover {
  text-decoration: underline;
}

@media (max-width: 860px) {
  .feature-grid {
    grid-template-columns: 1fr;
  }
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}

/* ---------- 关于 ---------- */

.about-grid {
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: 48px;
  align-items: start;
}

.about-text p {
  color: var(--text-2);
  font-size: 16px;
  margin-bottom: 16px;
}

.about-text strong {
  color: var(--text);
}

.principles {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.principles li {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 18px 22px;
  box-shadow: var(--shadow-sm);
}

.principles strong {
  display: block;
  font-size: 15px;
  margin-bottom: 4px;
}

.principles span {
  font-size: 14px;
  color: var(--text-3);
}

/* ---------- 联系 ---------- */

.contact-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 340px));
  justify-content: center;
  gap: 24px;
}

.contact-card {
  display: flex;
  flex-direction: column;
  gap: 4px;
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px 28px;
  text-decoration: none;
  box-shadow: var(--shadow-sm);
  transition: transform 0.2s, box-shadow 0.2s, border-color 0.2s;
}

.contact-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
  border-color: var(--accent);
}

.contact-card strong {
  font-size: 16px;
}

.contact-card span {
  color: var(--text-2);
  font-size: 14px;
}

/* ---------- 页脚 ---------- */

.footer {
  border-top: 1px solid var(--border);
  padding: 28px 0;
  background: var(--bg-alt);
}

.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 8px;
  font-size: 14px;
  color: var(--text-3);
}

.footer a {
  color: var(--text-3);
  text-decoration: none;
}

.footer-links {
  display: flex;
  gap: 16px;
}

.footer a:hover {
  color: var(--text-2);
}

/* ---------- 入场动画 ---------- */

.reveal {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.reveal.visible {
  opacity: 1;
  transform: none;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  .reveal {
    opacity: 1;
    transform: none;
    transition: none;
  }
}

/* ---------- 响应式 ---------- */

@media (max-width: 860px) {
  .card-grid,
  .about-grid {
    grid-template-columns: 1fr;
  }
  .about-grid {
    gap: 32px;
  }
  .contact-grid {
    grid-template-columns: 1fr;
    max-width: 420px;
    margin: 0 auto;
  }
}

@media (max-width: 640px) {
  .hero {
    padding: 132px 0 72px;
  }
  .section {
    padding: 72px 0;
  }
  .hero-stats {
    gap: 28px;
    margin-top: 48px;
  }
  .hero-stats strong {
    font-size: 26px;
  }
  .hero-actions {
    flex-direction: column;
    align-items: center;
  }
  .card {
    padding: 22px;
  }
  .card-featured {
    padding: 26px 22px;
  }

  .nav-menu {
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    flex-direction: column;
    gap: 0;
    background: #fff;
    border-bottom: 1px solid var(--border);
    box-shadow: var(--shadow-md);
    display: none;
  }
  .nav-menu.open {
    display: flex;
  }
  .nav-menu a {
    padding: 14px 24px;
    border-top: 1px solid var(--border);
  }
  .nav-toggle {
    display: flex;
  }
}