/* ============================
   全局样式 & 设计系统
   ============================ */
:root {
  --primary: #4F8EF7;
  --primary-dark: #2563EB;
  --secondary: #7C3AED;
  --accent: #06B6D4;
  --bg-dark: #0A0E1A;
  --bg-card: #111827;
  --bg-card2: #161D2E;
  --border: rgba(255,255,255,0.08);
  --text-primary: #F1F5F9;
  --text-secondary: #94A3B8;
  --text-muted: #64748B;
  --gradient: linear-gradient(135deg, #4F8EF7 0%, #7C3AED 100%);
  --gradient-text: linear-gradient(135deg, #60A5FA, #A78BFA);
  --shadow-card: 0 4px 32px rgba(0,0,0,0.4);
  --radius: 12px;
  --radius-lg: 20px;
  --transition: 0.3s ease;
  --font: 'Inter', 'PingFang SC', 'Microsoft YaHei', sans-serif;
}

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

html { scroll-behavior: smooth; }

body {
  font-family: var(--font);
  background: var(--bg-dark);
  color: var(--text-primary);
  line-height: 1.6;
  overflow-x: hidden;
}

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

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

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

/* ============================
   导航栏
   ============================ */
.navbar {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 1000;
  padding: 0 0;
  transition: background var(--transition), box-shadow var(--transition);
}

.navbar.scrolled {
  background: rgba(10, 14, 26, 0.95);
  backdrop-filter: blur(20px);
  box-shadow: 0 1px 0 var(--border);
}

.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 68px;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.3rem;
  font-weight: 700;
  letter-spacing: -0.5px;
}

.logo-icon {
  width: 36px; height: 36px;
  background: var(--gradient);
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1rem;
}

.logo-text {
  background: var(--gradient-text);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 8px;
  list-style: none;
}

.nav-links a {
  padding: 8px 16px;
  border-radius: 8px;
  font-size: 0.9rem;
  color: var(--text-secondary);
  transition: color var(--transition), background var(--transition);
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--text-primary);
  background: rgba(79,142,247,0.1);
}

.nav-cta {
  background: var(--gradient) !important;
  color: white !important;
  padding: 8px 20px !important;
  border-radius: 8px !important;
  font-weight: 600 !important;
  transition: opacity var(--transition) !important;
}

.nav-cta:hover { opacity: 0.85 !important; background: var(--gradient) !important; }

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  padding: 4px;
}

.nav-toggle span {
  display: block;
  width: 24px; height: 2px;
  background: var(--text-primary);
  border-radius: 2px;
  transition: var(--transition);
}

/* ============================
   通用区块
   ============================ */
.section {
  padding: 100px 0;
}

.section-header {
  text-align: center;
  margin-bottom: 64px;
}

.section-tag {
  display: inline-block;
  padding: 6px 16px;
  background: rgba(79,142,247,0.12);
  border: 1px solid rgba(79,142,247,0.3);
  border-radius: 100px;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--primary);
  letter-spacing: 1px;
  text-transform: uppercase;
  margin-bottom: 16px;
}

.section-title {
  font-size: clamp(1.8rem, 3vw, 2.6rem);
  font-weight: 800;
  letter-spacing: -0.5px;
  line-height: 1.2;
  margin-bottom: 16px;
}

.section-title .highlight {
  background: var(--gradient-text);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.section-desc {
  font-size: 1rem;
  color: var(--text-secondary);
  max-width: 560px;
  margin: 0 auto;
  line-height: 1.7;
}

/* ============================
   按钮
   ============================ */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 28px;
  border-radius: var(--radius);
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  border: none;
  transition: all var(--transition);
}

.btn-primary {
  background: var(--gradient);
  color: white;
  box-shadow: 0 4px 20px rgba(79,142,247,0.35);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 30px rgba(79,142,247,0.5);
}

.btn-outline {
  background: transparent;
  color: var(--text-primary);
  border: 1px solid var(--border);
}

.btn-outline:hover {
  background: rgba(255,255,255,0.05);
  border-color: rgba(255,255,255,0.2);
  transform: translateY(-2px);
}

.btn-lg {
  padding: 16px 36px;
  font-size: 1rem;
  border-radius: 14px;
}

/* ============================
   卡片
   ============================ */
.card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 32px;
  transition: transform var(--transition), border-color var(--transition), box-shadow var(--transition);
}

.card:hover {
  transform: translateY(-4px);
  border-color: rgba(79,142,247,0.3);
  box-shadow: 0 20px 60px rgba(79,142,247,0.1);
}

/* ============================
   页脚
   ============================ */
.footer {
  background: var(--bg-card);
  border-top: 1px solid var(--border);
  padding: 60px 0 32px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 48px;
  margin-bottom: 48px;
}

.footer-brand p {
  color: var(--text-secondary);
  font-size: 0.9rem;
  margin-top: 16px;
  line-height: 1.7;
  max-width: 280px;
}

.footer-col h4 {
  font-size: 0.85rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--text-muted);
  margin-bottom: 20px;
}

.footer-col ul { list-style: none; }

.footer-col ul li {
  margin-bottom: 12px;
}

.footer-col ul li a {
  color: var(--text-secondary);
  font-size: 0.9rem;
  transition: color var(--transition);
}

.footer-col ul li a:hover {
  color: var(--primary);
}

.footer-bottom {
  border-top: 1px solid var(--border);
  padding-top: 28px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
}

.footer-bottom p {
  color: var(--text-muted);
  font-size: 0.85rem;
}

.footer-social {
  display: flex;
  gap: 12px;
}

.footer-social a {
  width: 36px; height: 36px;
  background: rgba(255,255,255,0.05);
  border: 1px solid var(--border);
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.85rem;
  color: var(--text-secondary);
  transition: all var(--transition);
}

.footer-social a:hover {
  background: rgba(79,142,247,0.15);
  border-color: rgba(79,142,247,0.4);
  color: var(--primary);
}

/* ============================
   粒子背景
   ============================ */
#particles-canvas {
  position: absolute;
  top: 0; left: 0;
  width: 100%; height: 100%;
  pointer-events: none;
  z-index: 0;
}

/* ============================
   动画
   ============================ */
.fade-in {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}

.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

.fade-delay-1 { transition-delay: 0.1s; }
.fade-delay-2 { transition-delay: 0.2s; }
.fade-delay-3 { transition-delay: 0.3s; }
.fade-delay-4 { transition-delay: 0.4s; }

/* ============================
   响应式
   ============================ */
@media (max-width: 900px) {
  .footer-grid {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 768px) {
  .nav-links { display: none; }
  .nav-toggle { display: flex; }

  .nav-links.open {
    display: flex;
    flex-direction: column;
    position: fixed;
    top: 68px; left: 0; right: 0;
    background: rgba(10, 14, 26, 0.98);
    backdrop-filter: blur(20px);
    padding: 24px;
    gap: 8px;
    border-bottom: 1px solid var(--border);
  }

  .section { padding: 72px 0; }

  .footer-grid {
    grid-template-columns: 1fr;
    gap: 32px;
  }
}

@media (max-width: 480px) {
  .btn-lg {
    padding: 14px 24px;
    font-size: 0.9rem;
  }
}

/* ============================
   滚动条
   ============================ */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: var(--bg-dark); }
::-webkit-scrollbar-thumb {
  background: rgba(79,142,247,0.4);
  border-radius: 3px;
}
::-webkit-scrollbar-thumb:hover {
  background: rgba(79,142,247,0.7);
}

/* ============================
   页面Hero光晕背景
   ============================ */
.page-hero {
  position: relative;
  padding: 160px 0 80px;
  overflow: hidden;
  text-align: center;
}

.page-hero::before {
  content: '';
  position: absolute;
  top: -200px; left: 50%;
  transform: translateX(-50%);
  width: 800px; height: 600px;
  background: radial-gradient(ellipse at center, rgba(79,142,247,0.12) 0%, transparent 70%);
  pointer-events: none;
}

.page-hero-title {
  font-size: clamp(2rem, 4vw, 3rem);
  font-weight: 800;
  letter-spacing: -1px;
  margin-bottom: 16px;
}

.page-hero-desc {
  font-size: 1.05rem;
  color: var(--text-secondary);
  max-width: 500px;
  margin: 0 auto;
}

/* ============================
   通用网格
   ============================ */
.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

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

@media (max-width: 900px) {
  .grid-3 { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 600px) {
  .grid-3, .grid-2 { grid-template-columns: 1fr; }
}

/* ============================
   图标圆形背景
   ============================ */
.icon-box {
  width: 52px; height: 52px;
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.4rem;
  margin-bottom: 20px;
  background: rgba(79,142,247,0.12);
  border: 1px solid rgba(79,142,247,0.2);
}

/* ============================
   徽章标签
   ============================ */
.badge {
  display: inline-block;
  padding: 4px 10px;
  border-radius: 100px;
  font-size: 0.75rem;
  font-weight: 600;
}

.badge-blue {
  background: rgba(79,142,247,0.15);
  color: #60A5FA;
  border: 1px solid rgba(79,142,247,0.25);
}

.badge-purple {
  background: rgba(124,58,237,0.15);
  color: #A78BFA;
  border: 1px solid rgba(124,58,237,0.25);
}

.badge-cyan {
  background: rgba(6,182,212,0.15);
  color: #22D3EE;
  border: 1px solid rgba(6,182,212,0.25);
}