/* ===== 北京智三科技有限公司 - 企业门户样式 ===== */
/* ===== CSS Variables ===== */
:root {
  --primary: #1a6bff;
  --primary-dark: #0a4fc4;
  --primary-light: #e8f0ff;
  --secondary: #00c9a7;
  --accent: #ff6b35;
  --dark: #1a2332;
  --dark-2: #2a3a52;
  --text: #333;
  --text-light: #666;
  --bg: #fff;
  --bg-gray: #f5f8fc;
  --bg-dark: #0d1520;
  --border: #e5e9f0;
  --shadow: 0 2px 20px rgba(26, 107, 255, 0.08);
  --shadow-hover: 0 8px 40px rgba(26, 107, 255, 0.15);
  --radius: 12px;
  --radius-lg: 20px;
  --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --font: 'PingFang SC', 'Microsoft YaHei', -apple-system, BlinkMacSystemFont, sans-serif;
}

/* ===== Reset ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; font-size: 16px; }
body {
  font-family: var(--font);
  color: var(--text);
  line-height: 1.7;
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
}
a { color: var(--primary); text-decoration: none; transition: var(--transition); }
a:hover { color: var(--primary-dark); }
img { max-width: 100%; height: auto; display: block; }
ul { list-style: none; }
.container { max-width: 1200px; margin: 0 auto; padding: 0 20px; }

/* ===== Typography ===== */
.section-title {
  text-align: center;
  margin-bottom: 50px;
}
.section-title h2 {
  font-size: 2rem;
  font-weight: 700;
  color: var(--dark);
  position: relative;
  display: inline-block;
  margin-bottom: 15px;
}
.section-title h2::after {
  content: '';
  display: block;
  width: 50px;
  height: 3px;
  background: linear-gradient(90deg, var(--primary), var(--secondary));
  margin: 12px auto 0;
  border-radius: 2px;
}
.section-title p {
  color: var(--text-light);
  font-size: 1.05rem;
  max-width: 600px;
  margin: 0 auto;
}

/* ===== Header / Navbar ===== */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: rgba(255,255,255,0.97);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
  transition: var(--transition);
}
.header.scrolled { box-shadow: 0 2px 30px rgba(0,0,0,0.08); }
.navbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 70px;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}
.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--dark);
}
.logo-icon {
  width: 40px;
  height: 40px;
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-weight: 800;
  font-size: 1rem;
}
.nav-links { display: flex; align-items: center; gap: 5px; }
.nav-links a {
  padding: 8px 18px;
  color: var(--text);
  font-weight: 500;
  font-size: 0.95rem;
  border-radius: 8px;
  transition: var(--transition);
  position: relative;
}
.nav-links a:hover,
.nav-links a.active {
  color: var(--primary);
  background: var(--primary-light);
}
.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  padding: 5px;
  background: none;
  border: none;
}
.nav-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--dark);
  border-radius: 2px;
  transition: var(--transition);
}

/* ===== Hero Section ===== */
.hero {
  padding: 140px 0 80px;
  background: linear-gradient(135deg, #0d1520 0%, #1a2332 50%, #1a3060 100%);
  color: #fff;
  position: relative;
  overflow: hidden;
}
.hero::before {
  content: '';
  position: absolute;
  top: -50%;
  right: -20%;
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, rgba(26,107,255,0.15) 0%, transparent 70%);
  border-radius: 50%;
}
.hero::after {
  content: '';
  position: absolute;
  bottom: -30%;
  left: -10%;
  width: 400px;
  height: 400px;
  background: radial-gradient(circle, rgba(0,201,167,0.1) 0%, transparent 70%);
  border-radius: 50%;
}
.hero .container {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  align-items: center;
}
.hero-content h1 {
  font-size: 2.8rem;
  font-weight: 800;
  line-height: 1.2;
  margin-bottom: 20px;
}
.hero-content h1 span {
  background: linear-gradient(90deg, var(--primary), var(--secondary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.hero-content p {
  font-size: 1.1rem;
  color: rgba(255,255,255,0.75);
  margin-bottom: 30px;
  max-width: 500px;
}
.hero-buttons { display: flex; gap: 15px; flex-wrap: wrap; }
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 14px 32px;
  border-radius: 8px;
  font-weight: 600;
  font-size: 1rem;
  cursor: pointer;
  border: none;
  transition: var(--transition);
  font-family: var(--font);
}
.btn-primary { background: var(--primary); color: #fff; }
.btn-primary:hover { background: var(--primary-dark); transform: translateY(-2px); box-shadow: 0 8px 25px rgba(26,107,255,0.35); }
.btn-outline { background: transparent; color: #fff; border: 2px solid rgba(255,255,255,0.3); }
.btn-outline:hover { border-color: #fff; transform: translateY(-2px); }
.btn-outline-light { background: transparent; color: var(--primary); border: 2px solid var(--primary); }
.btn-outline-light:hover { background: var(--primary); color: #fff; }

/* Hero Stats */
.hero-visual {
  display: flex;
  flex-direction: column;
  gap: 20px;
}
.hero-stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 15px;
}
.stat-card {
  background: rgba(255,255,255,0.06);
  border: 1px solid rgba(255,255,255,0.1);
  border-radius: var(--radius);
  padding: 25px 20px;
  text-align: center;
  backdrop-filter: blur(10px);
}
.stat-card .number {
  font-size: 2rem;
  font-weight: 800;
  color: #fff;
  line-height: 1.2;
}
.stat-card .number span { color: var(--secondary); }
.stat-card .label {
  font-size: 0.85rem;
  color: rgba(255,255,255,0.6);
  margin-top: 5px;
}
.hero-code {
  background: rgba(255,255,255,0.05);
  border: 1px solid rgba(255,255,255,0.1);
  border-radius: var(--radius);
  padding: 20px;
  backdrop-filter: blur(10px);
}
.hero-code .code-header {
  display: flex;
  gap: 8px;
  margin-bottom: 15px;
}
.hero-code .dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
}
.hero-code .dot.r { background: #ff5f56; }
.hero-code .dot.y { background: #ffbd2e; }
.hero-code .dot.g { background: #27c93f; }
.hero-code code {
  display: block;
  font-family: 'JetBrains Mono', 'Consolas', monospace;
  font-size: 0.85rem;
  color: rgba(255,255,255,0.7);
  line-height: 1.8;
}
.hero-code code .kw { color: #c792ea; }
.hero-code code .fn { color: #82aaff; }
.hero-code code .str { color: #c3e88d; }
.hero-code code .cm { color: #546e7a; }
.hero-code code .num { color: #f78c6c; }

/* ===== Feature / Section Styles ===== */
section { padding: 80px 0; }
section.bg-light { background: var(--bg-gray); }
section.bg-dark { background: var(--bg-dark); color: #fff; }

/* ===== Services Section ===== */
.services-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 25px;
}
.service-card {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 35px 30px;
  transition: var(--transition);
  cursor: default;
}
.service-card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-hover);
  border-color: var(--primary);
}
.service-icon {
  width: 60px;
  height: 60px;
  border-radius: 14px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  margin-bottom: 20px;
}
.service-card h3 { font-size: 1.2rem; margin-bottom: 12px; color: var(--dark); }
.service-card p { color: var(--text-light); font-size: 0.92rem; line-height: 1.7; }
.service-card .learn-more {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  margin-top: 15px;
  font-weight: 600;
  font-size: 0.9rem;
}

/* ===== About Section ===== */
.about-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  align-items: center;
}
.about-image {
  background: linear-gradient(135deg, var(--primary-light), #d5e5ff);
  border-radius: var(--radius-lg);
  height: 400px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 4rem;
  color: var(--primary);
  position: relative;
  overflow: hidden;
}
.about-image::before {
  content: '';
  position: absolute;
  width: 200px;
  height: 200px;
  border: 3px solid rgba(26,107,255,0.15);
  border-radius: 50%;
  animation: pulse 3s ease-in-out infinite;
}
@keyframes pulse {
  0%, 100% { transform: scale(1); opacity: 0.5; }
  50% { transform: scale(1.2); opacity: 1; }
}
.about-text h3 {
  font-size: 1.6rem;
  margin-bottom: 20px;
  color: var(--dark);
}
.about-text p { color: var(--text-light); margin-bottom: 15px; }
.about-features { margin-top: 25px; }
.about-features li {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 0;
  color: var(--text);
}
.about-features li::before {
  content: '✓';
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 22px;
  height: 22px;
  background: var(--secondary);
  color: #fff;
  border-radius: 50%;
  font-size: 0.8rem;
  flex-shrink: 0;
}

/* ===== Clients / Partners ===== */
.clients-grid {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 30px;
  align-items: center;
}
.client-item {
  padding: 20px 35px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  font-weight: 600;
  color: var(--text-light);
  font-size: 0.95rem;
  transition: var(--transition);
}
.client-item:hover {
  border-color: var(--primary);
  color: var(--primary);
  box-shadow: var(--shadow);
}

/* ===== News Section ===== */
.news-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 25px;
}
.news-card {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  transition: var(--transition);
}
.news-card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-hover);
}
.news-img {
  height: 200px;
  background: linear-gradient(135deg, var(--primary-light), #e0eaff);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2.5rem;
  color: var(--primary);
}
.news-body { padding: 25px; }
.news-tag {
  display: inline-block;
  padding: 4px 12px;
  background: var(--primary-light);
  color: var(--primary);
  border-radius: 20px;
  font-size: 0.8rem;
  font-weight: 600;
  margin-bottom: 10px;
}
.news-body h3 { font-size: 1.05rem; margin-bottom: 10px; line-height: 1.5; }
.news-body p { color: var(--text-light); font-size: 0.88rem; }
.news-body .date { color: #999; font-size: 0.82rem; margin-top: 12px; }

/* ===== Contact Section ===== */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 50px;
}
.contact-info h3 { font-size: 1.4rem; margin-bottom: 20px; color: var(--dark); }
.contact-info > p { color: var(--text-light); margin-bottom: 30px; }
.contact-item {
  display: flex;
  gap: 15px;
  margin-bottom: 20px;
}
.contact-item .icon {
  width: 50px;
  height: 50px;
  background: var(--primary-light);
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  flex-shrink: 0;
}
.contact-item .info h4 { font-size: 0.95rem; color: var(--dark); margin-bottom: 4px; }
.contact-item .info p { color: var(--text-light); font-size: 0.9rem; }
.contact-form { background: var(--bg); border: 1px solid var(--border); border-radius: var(--radius-lg); padding: 35px; }
.contact-form h3 { font-size: 1.2rem; margin-bottom: 25px; color: var(--dark); }
.form-row { display: grid; grid-template-columns: 1fr 1fr; gap: 15px; }
.form-group { margin-bottom: 15px; }
.form-group label { display: block; font-weight: 600; font-size: 0.9rem; margin-bottom: 6px; color: var(--dark); }
.form-group input,
.form-group textarea,
.form-group select {
  width: 100%;
  padding: 12px 15px;
  border: 1px solid var(--border);
  border-radius: 8px;
  font-size: 0.95rem;
  font-family: var(--font);
  transition: var(--transition);
  color: var(--text);
  background: var(--bg);
}
.form-group input:focus,
.form-group textarea:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(26,107,255,0.1);
}
.form-group textarea { min-height: 120px; resize: vertical; }
.submit-btn {
  width: 100%;
  padding: 14px;
  background: var(--primary);
  color: #fff;
  border: none;
  border-radius: 8px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition);
  font-family: var(--font);
}
.submit-btn:hover { background: var(--primary-dark); }
.submit-btn:disabled { opacity: 0.6; cursor: not-allowed; }
.form-message {
  padding: 12px 16px;
  border-radius: 8px;
  margin-bottom: 15px;
  font-size: 0.9rem;
  display: none;
}
.form-message.success { display: block; background: #e8f5e9; color: #2e7d32; border: 1px solid #a5d6a7; }
.form-message.error { display: block; background: #fbe9e7; color: #c62828; border: 1px solid #ef9a9a; }

/* ===== Page Banner (Inner Pages) ===== */
.page-banner {
  padding: 120px 0 60px;
  background: linear-gradient(135deg, #0d1520 0%, #1a3060 100%);
  color: #fff;
  text-align: center;
}
.page-banner h1 { font-size: 2.2rem; font-weight: 700; margin-bottom: 10px; }
.page-banner p { color: rgba(255,255,255,0.7); max-width: 600px; margin: 0 auto; }

/* ===== About Page ===== */
.mission-vision {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 25px;
  margin-top: 40px;
}
.mv-card {
  padding: 35px;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  text-align: center;
}
.mv-card .icon { font-size: 2.5rem; margin-bottom: 15px; }
.mv-card h3 { font-size: 1.2rem; margin-bottom: 10px; }
.mv-card p { color: var(--text-light); font-size: 0.92rem; }

/* Timeline */
.timeline {
  position: relative;
  padding-left: 30px;
}
.timeline::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 2px;
  background: linear-gradient(180deg, var(--primary), var(--secondary));
}
.timeline-item {
  position: relative;
  padding: 0 0 35px 30px;
}
.timeline-item::before {
  content: '';
  position: absolute;
  left: -6px;
  top: 5px;
  width: 14px;
  height: 14px;
  background: var(--primary);
  border-radius: 50%;
  border: 3px solid #fff;
  box-shadow: 0 0 0 2px var(--primary);
}
.timeline-item .year {
  font-weight: 700;
  color: var(--primary);
  font-size: 1.1rem;
  margin-bottom: 5px;
}
.timeline-item p { color: var(--text-light); }

/* ===== Products Page ===== */
.product-hero-card {
  background: linear-gradient(135deg, var(--primary-light), #e0eaff);
  border-radius: var(--radius-lg);
  padding: 50px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 40px;
  align-items: center;
  margin-bottom: 30px;
}
.product-hero-card .icon { font-size: 5rem; text-align: center; }
.product-hero-card h3 { font-size: 1.4rem; margin-bottom: 12px; }
.product-hero-card p { color: var(--text-light); }
.product-features { margin-top: 20px; }
.product-features li {
  padding: 6px 0;
  display: flex;
  align-items: center;
  gap: 8px;
  color: var(--text);
}
.product-features li::before {
  content: '→';
  color: var(--primary);
  font-weight: 700;
}
.tech-stack {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 15px;
}
.tech-tag {
  padding: 4px 14px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 20px;
  font-size: 0.82rem;
  color: var(--text-light);
}

/* ===== Footer ===== */
.footer {
  background: var(--bg-dark);
  color: rgba(255,255,255,0.7);
  padding: 60px 0 0;
}
.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 40px;
}
.footer-about h3 {
  color: #fff;
  font-size: 1.2rem;
  margin-bottom: 15px;
}
.footer-about p { font-size: 0.9rem; line-height: 1.8; }
.footer-col h4 {
  color: #fff;
  font-size: 1rem;
  margin-bottom: 20px;
  font-weight: 600;
}
.footer-col a {
  display: block;
  padding: 6px 0;
  color: rgba(255,255,255,0.6);
  font-size: 0.9rem;
}
.footer-col a:hover { color: var(--primary); }
.footer-bottom {
  border-top: 1px solid rgba(255,255,255,0.08);
  padding: 20px 0;
  margin-top: 40px;
  text-align: center;
  font-size: 0.85rem;
  color: rgba(255,255,255,0.4);
}

/* ===== Back to Top ===== */
.back-to-top {
  position: fixed;
  bottom: 30px;
  right: 30px;
  width: 45px;
  height: 45px;
  border-radius: 50%;
  background: var(--primary);
  color: #fff;
  border: none;
  font-size: 1.2rem;
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transition: var(--transition);
  z-index: 999;
  box-shadow: 0 4px 15px rgba(26,107,255,0.3);
}
.back-to-top.show { opacity: 1; visibility: visible; }
.back-to-top:hover { transform: translateY(-3px); background: var(--primary-dark); }

/* ===== Page Loader ===== */
.page-loader {
  position: fixed;
  top: 0; left: 0; right: 0; bottom: 0;
  background: var(--bg);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 9999;
  transition: opacity 0.4s, visibility 0.4s;
}
.page-loader.hidden { opacity: 0; visibility: hidden; }
.loader-spinner {
  width: 40px;
  height: 40px;
  border: 3px solid var(--border);
  border-top-color: var(--primary);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* ===== Responsive ===== */
@media (max-width: 992px) {
  .hero .container { grid-template-columns: 1fr; gap: 40px; }
  .hero-content h1 { font-size: 2.2rem; }
  .hero-stats { grid-template-columns: repeat(3, 1fr); }
  .services-grid { grid-template-columns: 1fr 1fr; }
  .about-grid { grid-template-columns: 1fr; gap: 40px; }
  .news-grid { grid-template-columns: 1fr 1fr; }
  .contact-grid { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .product-hero-card { grid-template-columns: 1fr; padding: 30px; }
}

@media (max-width: 768px) {
  .nav-links {
    position: fixed;
    top: 70px;
    left: 0;
    right: 0;
    background: var(--bg);
    flex-direction: column;
    padding: 20px;
    border-bottom: 1px solid var(--border);
    transform: translateY(-100%);
    opacity: 0;
    visibility: hidden;
    transition: var(--transition);
    box-shadow: var(--shadow);
  }
  .nav-links.open { transform: translateY(0); opacity: 1; visibility: visible; }
  .nav-links a { width: 100%; padding: 12px 16px; }
  .nav-toggle { display: flex; }
  .hero { padding: 120px 0 60px; }
  .hero-content h1 { font-size: 1.8rem; }
  .hero-stats { grid-template-columns: repeat(3, 1fr); gap: 10px; }
  .stat-card { padding: 15px 10px; }
  .stat-card .number { font-size: 1.5rem; }
  .services-grid { grid-template-columns: 1fr; }
  .news-grid { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; }
  .form-row { grid-template-columns: 1fr; }
  .mission-vision { grid-template-columns: 1fr; }
  section { padding: 50px 0; }
  .section-title h2 { font-size: 1.6rem; }
  .page-banner { padding: 100px 0 40px; }
  .page-banner h1 { font-size: 1.7rem; }
}

@media (max-width: 480px) {
  .hero-content h1 { font-size: 1.5rem; }
  .hero-buttons { flex-direction: column; }
  .btn { justify-content: center; }
  .stat-card .number { font-size: 1.2rem; }
}