/* === Bi安官网 - 安全专业易用智能科技主题 === */
:root {
  --bg-primary: #0a1628;
  --bg-secondary: #0d1f3c;
  --bg-card: #111d35;
  --bg-card-hover: #152340;
  --text-primary: #ffffff;
  --text-secondary: #b0bec5;
  --text-muted: #78909c;
  --accent-blue: #2563eb;
  --accent-blue-light: #3b82f6;
  --accent-purple: #7c3aed;
  --accent-green: #10b981;
  --gradient-primary: linear-gradient(135deg, #2563eb, #7c3aed);
  --gradient-hero: linear-gradient(135deg, #0a1628 0%, #1a1050 50%, #0a1628 100%);
  --border-color: rgba(37, 99, 235, 0.15);
  --shadow-glow: 0 0 40px rgba(37, 99, 235, 0.15);
  --shadow-card: 0 4px 24px rgba(0, 0, 0, 0.3);
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 24px;
  --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --max-width: 1200px;
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

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

/* === Skip link === */
.skip-link {
  position: absolute;
  top: -100%;
  left: 16px;
  background: var(--accent-blue);
  color: #fff;
  padding: 8px 16px;
  border-radius: 0 0 var(--radius-sm) var(--radius-sm);
  z-index: 1000;
  text-decoration: none;
  transition: top 0.3s;
}
.skip-link:focus {
  top: 0;
}

/* === Header & Navigation === */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 999;
  background: rgba(10, 22, 40, 0.85);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border-color);
  transition: var(--transition);
}

.site-header.scrolled {
  background: rgba(10, 22, 40, 0.95);
  box-shadow: 0 4px 30px rgba(0, 0, 0, 0.5);
}

.nav-container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 70px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: var(--text-primary);
}

.brand-logo {
  width: 40px;
  height: 40px;
  background: var(--gradient-primary);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 20px;
  font-weight: 700;
  color: #fff;
}

.brand-text {
  font-size: 1.3rem;
  font-weight: 700;
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

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

.nav-menu a {
  color: var(--text-secondary);
  text-decoration: none;
  padding: 8px 16px;
  border-radius: var(--radius-sm);
  font-size: 0.95rem;
  font-weight: 500;
  transition: var(--transition);
  position: relative;
}

.nav-menu a:hover,
.nav-menu a.active {
  color: var(--text-primary);
  background: rgba(37, 99, 235, 0.1);
}

.nav-menu a.active::after {
  content: '';
  position: absolute;
  bottom: 2px;
  left: 50%;
  transform: translateX(-50%);
  width: 20px;
  height: 2px;
  background: var(--accent-blue);
  border-radius: 1px;
}

.nav-download {
  background: var(--gradient-primary) !important;
  color: #fff !important;
  padding: 10px 22px !important;
  font-weight: 600 !important;
}

.nav-download:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 25px rgba(37, 99, 235, 0.4) !important;
  background: var(--gradient-primary) !important;
}

.hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  background: none;
  border: none;
  padding: 4px;
}

.hamburger span {
  display: block;
  width: 26px;
  height: 2px;
  background: var(--text-primary);
  border-radius: 2px;
  transition: var(--transition);
}

/* === Hero Section === */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  background: var(--gradient-hero);
  position: relative;
  overflow: hidden;
  padding: 100px 24px 80px;
}

.hero::before {
  content: '';
  position: absolute;
  top: -50%;
  right: -20%;
  width: 800px;
  height: 800px;
  background: radial-gradient(circle, rgba(37, 99, 235, 0.15) 0%, transparent 70%);
  border-radius: 50%;
}

.hero::after {
  content: '';
  position: absolute;
  bottom: -30%;
  left: -10%;
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, rgba(124, 58, 237, 0.1) 0%, transparent 70%);
  border-radius: 50%;
}

.hero-container {
  max-width: var(--max-width);
  margin: 0 auto;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  align-items: center;
  position: relative;
  z-index: 1;
}

.hero-content h1 {
  font-size: 3.2rem;
  font-weight: 800;
  line-height: 1.2;
  margin-bottom: 24px;
  background: linear-gradient(135deg, #ffffff 0%, #a0c4ff 50%, #c4b5fd 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-content p {
  font-size: 1.2rem;
  color: var(--text-secondary);
  margin-bottom: 36px;
  line-height: 1.8;
  max-width: 540px;
}

.hero-buttons {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 14px 32px;
  border-radius: var(--radius-md);
  font-size: 1rem;
  font-weight: 600;
  text-decoration: none;
  transition: var(--transition);
  cursor: pointer;
  border: none;
}

.btn-primary {
  background: var(--gradient-primary);
  color: #fff;
  box-shadow: 0 4px 20px rgba(37, 99, 235, 0.3);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 30px rgba(37, 99, 235, 0.5);
}

.btn-secondary {
  background: rgba(255, 255, 255, 0.05);
  color: var(--text-primary);
  border: 1px solid rgba(255, 255, 255, 0.1);
}

.btn-secondary:hover {
  background: rgba(255, 255, 255, 0.1);
  border-color: rgba(255, 255, 255, 0.2);
  transform: translateY(-2px);
}

.hero-visual {
  display: flex;
  justify-content: center;
  align-items: center;
}

.hero-visual img {
  max-width: 100%;
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-glow);
  animation: float 6s ease-in-out infinite;
}

@keyframes float {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-20px); }
}

.hero-stats {
  display: flex;
  gap: 40px;
  margin-top: 40px;
  padding-top: 30px;
  border-top: 1px solid var(--border-color);
}

.stat-item {
  text-align: center;
}

.stat-number {
  font-size: 2rem;
  font-weight: 800;
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.stat-label {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-top: 4px;
}

/* === Features Section === */
.features {
  padding: 100px 24px;
  background: var(--bg-primary);
}

.section-header {
  text-align: center;
  max-width: 700px;
  margin: 0 auto 60px;
}

.section-header h2 {
  font-size: 2.4rem;
  font-weight: 700;
  margin-bottom: 16px;
  color: var(--text-primary);
}

.section-header p {
  font-size: 1.1rem;
  color: var(--text-secondary);
}

.features-grid {
  max-width: var(--max-width);
  margin: 0 auto;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.feature-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 36px 28px;
  transition: var(--transition);
  position: relative;
  overflow: hidden;
}

.feature-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: var(--gradient-primary);
  opacity: 0;
  transition: var(--transition);
}

.feature-card:hover::before {
  opacity: 1;
}

.feature-card:hover {
  background: var(--bg-card-hover);
  transform: translateY(-4px);
  box-shadow: var(--shadow-card);
  border-color: rgba(37, 99, 235, 0.3);
}

.feature-icon {
  width: 56px;
  height: 56px;
  background: rgba(37, 99, 235, 0.1);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 26px;
  margin-bottom: 20px;
}

.feature-icon.purple {
  background: rgba(124, 58, 237, 0.1);
}

.feature-icon.green {
  background: rgba(16, 185, 129, 0.1);
}

.feature-card h3 {
  font-size: 1.2rem;
  font-weight: 700;
  margin-bottom: 12px;
}

.feature-card p {
  font-size: 0.95rem;
  color: var(--text-secondary);
  line-height: 1.7;
}

/* === CTA Section === */
.cta {
  padding: 80px 24px;
  background: var(--bg-secondary);
  text-align: center;
}

.cta-container {
  max-width: var(--max-width);
  margin: 0 auto;
}

.cta h2 {
  font-size: 2.2rem;
  font-weight: 700;
  margin-bottom: 16px;
}

.cta p {
  font-size: 1.1rem;
  color: var(--text-secondary);
  margin-bottom: 36px;
}

.cta .btn-primary {
  padding: 16px 48px;
  font-size: 1.1rem;
}

/* === Page Header === */
.page-header {
  padding: 120px 24px 60px;
  background: var(--gradient-hero);
  text-align: center;
  position: relative;
  overflow: hidden;
}

.page-header::before {
  content: '';
  position: absolute;
  top: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, rgba(37, 99, 235, 0.1) 0%, transparent 70%);
}

.page-header h1 {
  font-size: 2.8rem;
  font-weight: 800;
  position: relative;
  z-index: 1;
}

.page-header p {
  font-size: 1.1rem;
  color: var(--text-secondary);
  margin-top: 16px;
  position: relative;
  z-index: 1;
}

/* === About Page === */
.about-section {
  padding: 80px 24px;
}

.about-container {
  max-width: var(--max-width);
  margin: 0 auto;
}

.about-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  align-items: center;
  margin-bottom: 80px;
}

.about-grid img {
  width: 100%;
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-card);
}

.about-text h2 {
  font-size: 2rem;
  font-weight: 700;
  margin-bottom: 20px;
}

.about-text p {
  color: var(--text-secondary);
  line-height: 1.8;
  margin-bottom: 16px;
}

/* Timeline */
.timeline {
  max-width: 800px;
  margin: 0 auto;
  padding: 0 24px;
}

.timeline h2 {
  text-align: center;
  font-size: 2rem;
  margin-bottom: 48px;
}

.timeline-list {
  position: relative;
  padding-left: 40px;
}

.timeline-list::before {
  content: '';
  position: absolute;
  left: 15px;
  top: 0;
  bottom: 0;
  width: 2px;
  background: var(--gradient-primary);
}

.timeline-item {
  position: relative;
  margin-bottom: 36px;
  padding: 20px 24px;
  background: var(--bg-card);
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
}

.timeline-item::before {
  content: '';
  position: absolute;
  left: -33px;
  top: 24px;
  width: 12px;
  height: 12px;
  background: var(--accent-blue);
  border-radius: 50%;
  border: 3px solid var(--bg-primary);
}

.timeline-year {
  font-size: 0.85rem;
  color: var(--accent-blue);
  font-weight: 700;
  margin-bottom: 4px;
}

.timeline-item h3 {
  font-size: 1.1rem;
  margin-bottom: 8px;
}

.timeline-item p {
  color: var(--text-secondary);
  font-size: 0.95rem;
}

/* Team */
.team-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
  margin-top: 40px;
}

.team-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 28px 20px;
  text-align: center;
  transition: var(--transition);
}

.team-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-card);
}

.team-card img {
  width: 80px;
  height: 80px;
  border-radius: 50%;
  margin-bottom: 16px;
  border: 3px solid var(--accent-blue);
}

.team-card h3 {
  font-size: 1.05rem;
  margin-bottom: 4px;
}

.team-card .role {
  color: var(--accent-blue);
  font-size: 0.85rem;
  margin-bottom: 8px;
}

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

/* === Services Page === */
.services-section {
  padding: 80px 24px;
}

.services-grid {
  max-width: var(--max-width);
  margin: 0 auto;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.service-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 36px 28px;
  transition: var(--transition);
}

.service-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-card);
  border-color: rgba(37, 99, 235, 0.4);
}

.service-card .icon {
  font-size: 36px;
  margin-bottom: 16px;
}

.service-card h3 {
  font-size: 1.2rem;
  font-weight: 700;
  margin-bottom: 12px;
}

.service-card p {
  color: var(--text-secondary);
  font-size: 0.95rem;
  line-height: 1.7;
  margin-bottom: 16px;
}

.service-card ul {
  list-style: none;
  padding: 0;
}

.service-card ul li {
  color: var(--text-secondary);
  font-size: 0.9rem;
  padding: 6px 0 6px 20px;
  position: relative;
}

.service-card ul li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 14px;
  width: 8px;
  height: 8px;
  background: var(--accent-green);
  border-radius: 50%;
}

/* === FAQ Page === */
.faq-section {
  padding: 80px 24px;
}

.faq-container {
  max-width: 800px;
  margin: 0 auto;
}

.faq-search {
  margin-bottom: 40px;
}

.faq-search input {
  width: 100%;
  padding: 14px 20px;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-size: 1rem;
  outline: none;
  transition: var(--transition);
}

.faq-search input:focus {
  border-color: var(--accent-blue);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.faq-category {
  margin-bottom: 36px;
}

.faq-category h2 {
  font-size: 1.5rem;
  font-weight: 700;
  margin-bottom: 16px;
  display: flex;
  align-items: center;
  gap: 12px;
}

.faq-category h2::before {
  content: '';
  width: 4px;
  height: 24px;
  background: var(--gradient-primary);
  border-radius: 2px;
}

.faq-item {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  margin-bottom: 12px;
  overflow: hidden;
  transition: var(--transition);
}

.faq-item:hover {
  border-color: rgba(37, 99, 235, 0.3);
}

.faq-item summary {
  padding: 18px 24px;
  cursor: pointer;
  font-weight: 600;
  font-size: 1.02rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  user-select: none;
  color: var(--text-primary);
}

.faq-item summary::-webkit-details-marker {
  display: none;
}

.faq-item summary::after {
  content: '+';
  font-size: 1.3rem;
  color: var(--accent-blue);
  transition: var(--transition);
  font-weight: 300;
}

.faq-item[open] summary::after {
  content: '-';
}

.faq-item .faq-answer {
  padding: 0 24px 20px;
  color: var(--text-secondary);
  font-size: 0.95rem;
  line-height: 1.8;
}

/* === Contact Page === */
.contact-section {
  padding: 80px 24px;
}

.contact-container {
  max-width: var(--max-width);
  margin: 0 auto;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
}

.contact-info h2 {
  font-size: 2rem;
  margin-bottom: 20px;
}

.contact-info p {
  color: var(--text-secondary);
  margin-bottom: 36px;
}

.contact-methods {
  display: grid;
  gap: 20px;
}

.contact-method {
  display: flex;
  align-items: flex-start;
  gap: 16px;
  padding: 20px;
  background: var(--bg-card);
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
}

.contact-method .icon {
  font-size: 24px;
  width: 48px;
  height: 48px;
  background: rgba(37, 99, 235, 0.1);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.contact-method h3 {
  font-size: 1rem;
  margin-bottom: 4px;
}

.contact-method p {
  color: var(--text-muted);
  font-size: 0.9rem;
  margin: 0;
}

.contact-form {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 36px;
}

.contact-form h3 {
  font-size: 1.4rem;
  margin-bottom: 24px;
}

.form-group {
  margin-bottom: 20px;
}

.form-group label {
  display: block;
  margin-bottom: 6px;
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-secondary);
}

.form-group input,
.form-group select,
.form-group textarea {
  width: 100%;
  padding: 12px 16px;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  color: var(--text-primary);
  font-size: 0.95rem;
  font-family: inherit;
  outline: none;
  transition: var(--transition);
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
  border-color: var(--accent-blue);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.form-group textarea {
  resize: vertical;
  min-height: 120px;
}

/* === Footer === */
.site-footer {
  background: var(--bg-secondary);
  border-top: 1px solid var(--border-color);
  padding: 60px 24px 30px;
}

.footer-container {
  max-width: var(--max-width);
  margin: 0 auto;
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 40px;
}

.footer-brand h3 {
  font-size: 1.3rem;
  margin-bottom: 12px;
}

.footer-brand p {
  color: var(--text-muted);
  font-size: 0.9rem;
  line-height: 1.7;
}

.footer-links h4 {
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 16px;
}

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

.footer-links ul li {
  margin-bottom: 10px;
}

.footer-links ul li a {
  color: var(--text-muted);
  text-decoration: none;
  font-size: 0.9rem;
  transition: var(--transition);
}

.footer-links ul li a:hover {
  color: var(--accent-blue);
}

.footer-bottom {
  max-width: var(--max-width);
  margin: 40px auto 0;
  padding-top: 24px;
  border-top: 1px solid var(--border-color);
  text-align: center;
  color: var(--text-muted);
  font-size: 0.85rem;
}

/* === Animations === */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

[data-animate] {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

[data-animate].visible {
  opacity: 1;
  transform: translateY(0);
}

/* === Pulse animation === */
@keyframes pulse {
  0%, 100% { box-shadow: 0 0 0 0 rgba(37, 99, 235, 0.4); }
  50% { box-shadow: 0 0 0 15px rgba(37, 99, 235, 0); }
}

.pulse {
  animation: pulse 2s infinite;
}

/* === Responsive === */
@media (max-width: 1024px) {
  .features-grid,
  .services-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .team-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .footer-container {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 768px) {
  .nav-menu {
    position: fixed;
    top: 70px;
    left: 0;
    right: 0;
    background: rgba(10, 22, 40, 0.98);
    flex-direction: column;
    padding: 24px;
    gap: 4px;
    transform: translateY(-120%);
    transition: var(--transition);
    backdrop-filter: blur(20px);
  }

  .nav-menu.active {
    transform: translateY(0);
  }

  .hamburger {
    display: flex;
  }

  .hero-container {
    grid-template-columns: 1fr;
    text-align: center;
  }

  .hero-content h1 {
    font-size: 2.2rem;
  }

  .hero-buttons {
    justify-content: center;
  }

  .hero-stats {
    justify-content: center;
    gap: 24px;
  }

  .hero-visual {
    order: -1;
  }

  .features-grid,
  .services-grid {
    grid-template-columns: 1fr;
  }

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

  .contact-container {
    grid-template-columns: 1fr;
  }

  .footer-container {
    grid-template-columns: 1fr;
  }

  .section-header h2 {
    font-size: 1.8rem;
  }
}

@media (max-width: 480px) {
  .hero-content h1 {
    font-size: 1.8rem;
  }
  .hero-stats {
    flex-direction: column;
    gap: 16px;
  }
  .page-header h1 {
    font-size: 2rem;
  }
}