/* ============================================
   集翼科技官网 - 蓝色科技极简风格
   ============================================ */

/* CSS Variables - 蓝色科技极简配色 */
:root {
  --color-primary: #2563eb;
  --color-primary-dark: #1A4CCF;
  --color-primary-darker: #1e3a8a;
  --color-primary-light: #eff6ff;
  --color-primary-50: #f0f6ff;
  --color-accent: #3b82f6;
  --color-dark: #0f172a;
  --color-gray-900: #0f172a;
  --color-gray-800: #1e293b;
  --color-gray-700: #334155;
  --color-gray-600: #475569;
  --color-gray-500: #64748b;
  --color-gray-400: #94a3b8;
  --color-gray-300: #cbd5e1;
  --color-gray-200: #e2e8f0;
  --color-gray-100: #f1f5f9;
  --color-gray-50: #f8fafc;
  --color-white: #ffffff;

  --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;

  --max-width: 1200px;
  --header-height: 68px;

  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.04);
  --shadow: 0 1px 3px rgba(0, 0, 0, 0.06), 0 1px 2px rgba(0, 0, 0, 0.04);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 12px 32px rgba(0, 0, 0, 0.08);
  --shadow-xl: 0 20px 48px rgba(0, 0, 0, 0.1);

  --transition: all 0.2s ease;
}

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

html {
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-family);
  color: var(--color-gray-800);
  background-color: var(--color-white);
  line-height: 1.6;
  overflow-x: hidden;
}

a {
  text-decoration: none;
  color: inherit;
  transition: var(--transition);
}

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

ul, ol {
  list-style: none;
}

/* ============================================
   Typography - 极简字体
   ============================================ */
h1, h2, h3, h4, h5, h6 {
  font-weight: 600;
  line-height: 1.3;
  color: var(--color-dark);
  letter-spacing: -0.01em;
}

h1 { font-size: 3rem; }
h2 { font-size: 2rem; }
h3 { font-size: 1.375rem; }
h4 { font-size: 1.125rem; }

p {
  line-height: 1.75;
  color: var(--color-gray-500);
}

/* ============================================
   Layout Utilities
   ============================================ */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

.section {
  padding: 96px 0;
}

.section-gray {
  background-color: var(--color-gray-50);
}

.section-dark {
  background-color: var(--color-dark);
  color: var(--color-white);
}

.section-header {
  text-align: center;
  margin-bottom: 56px;
}

.section-header .label {
  display: inline-block;
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--color-primary);
  background: var(--color-primary-light);
  padding: 5px 14px;
  border-radius: 6px;
  margin-bottom: 16px;
  letter-spacing: 0.02em;
  text-transform: uppercase;
}

.section-header h2 {
  margin-bottom: 12px;
}

.section-header p {
  max-width: 560px;
  margin: 0 auto;
  font-size: 1rem;
}

/* ============================================
   Header / Navigation - 极简导航
   ============================================ */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--header-height);
  background: rgba(255, 255, 255, 0.98);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  z-index: 1000;
  transition: var(--transition);
}

.header.scrolled {
  box-shadow: 0 1px 0 var(--color-gray-200);
}

.header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

.header-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--color-dark);
  letter-spacing: -0.01em;
}

.header-logo img {
  height: 44px;
  width: auto;
}

.header-logo .logo-icon {
  width: 32px;
  height: 32px;
  background: var(--color-primary);
  border-radius: 6px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-weight: 800;
  font-size: 0.75rem;
  letter-spacing: -0.02em;
}

.header-logo-img {
  height: 44px;
  width: auto;
  display: block;
}

.header-nav {
  display: flex;
  align-items: center;
  gap: 36px;
}

.header-nav a {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--color-gray-500);
  position: relative;
  padding: 4px 0;
  letter-spacing: 0;
}

.header-nav a:hover,
.header-nav a.active {
  color: var(--color-dark);
}

.header-nav a.active::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  right: 0;
  height: 2px;
  background: var(--color-primary);
  border-radius: 1px;
}

.header-cta {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 20px;
  background: var(--color-primary);
  color: var(--color-white);
  border-radius: 6px;
  font-size: 0.875rem;
  font-weight: 500;
  cursor: pointer;
  border: none;
  transition: var(--transition);
  white-space: nowrap;
}

.header-cta:hover {
  background: var(--color-primary-dark);
}

@media (max-width: 768px) {
  .header-cta {
    padding: 7px 14px;
    font-size: 0.8125rem;
  }
}

/* Mobile menu toggle */
.menu-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  padding: 4px;
  background: none;
  border: none;
}

.header-mobile-cta {
  display: none !important;
}

@media (max-width: 768px) {
  .header-mobile-cta {
    display: block !important;
    text-align: center;
    margin-top: 8px;
  }
}

.menu-toggle span {
  display: block;
  width: 20px;
  height: 2px;
  background: var(--color-dark);
  border-radius: 2px;
  transition: var(--transition);
}

/* ============================================
   Buttons - 极简按钮
   ============================================ */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 24px;
  border-radius: 6px;
  font-size: 0.9375rem;
  font-weight: 500;
  cursor: pointer;
  border: none;
  transition: var(--transition);
  text-align: center;
}

.btn-primary {
  background: var(--color-primary);
  color: var(--color-white);
}

.btn-primary:hover {
  background: var(--color-primary-dark);
}

.btn-secondary {
  background: transparent;
  color: var(--color-primary);
  border: 1.5px solid var(--color-primary);
}

.btn-secondary:hover {
  background: var(--color-primary);
  color: var(--color-white);
}

.btn-white {
  background: var(--color-white);
  color: var(--color-primary);
}

.btn-white:hover {
  background: rgba(255, 255, 255, 0.95);
}

.btn-lg {
  padding: 14px 32px;
  font-size: 1rem;
}

/* ============================================
   Cards - 极简卡片
   ============================================ */
.card {
  background: var(--color-white);
  border-radius: 12px;
  padding: 28px;
  transition: var(--transition);
  border: 1px solid var(--color-gray-200);
}

.card:hover {
  box-shadow: var(--shadow-lg);
  border-color: var(--color-gray-300);
}

.card-icon {
  width: 48px;
  height: 48px;
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 16px;
  font-size: 1.25rem;
}

.card-icon.blue {
  background: var(--color-primary-light);
  color: var(--color-primary);
}

.card-icon.cyan {
  background: #ecfeff;
  color: #0891b2;
}

.card-icon.indigo {
  background: #eef2ff;
  color: #4f46e5;
}

.card-icon.sky {
  background: #f0f9ff;
  color: #0284c7;
}

.card h3 {
  margin-bottom: 10px;
  font-size: 1.125rem;
}

.card p {
  font-size: 0.9375rem;
  line-height: 1.7;
}

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

.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.grid-4 {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}

.grid-5 {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 24px;
}

/* ============================================
   Footer - 极简页脚
   ============================================ */
.footer {
  background: var(--color-dark);
  color: var(--color-gray-400);
  padding: 56px 0 0;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 48px;
  padding-bottom: 40px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}

.footer-brand {
  max-width: 300px;
}

.footer-brand .logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--color-white);
  margin-bottom: 14px;
}

.footer-brand .logo .logo-icon {
  width: 32px;
  height: 32px;
  background: var(--color-primary);
  border-radius: 6px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-weight: 800;
  font-size: 0.75rem;
}

.footer-logo-img {
  height: 36px;
  width: auto;
  display: block;
  filter: brightness(0) invert(1);
  opacity: 0.9;
}

.footer-brand p {
  color: var(--color-gray-400);
  font-size: 0.8125rem;
  line-height: 1.7;
  margin-bottom: 12px;
}

/* Footer partner badges */
.footer-partners {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.partner-badge {
  display: inline-block;
  font-size: 0.625rem;
  color: var(--color-gray-400);
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid rgba(255, 255, 255, 0.08);
  padding: 2px 8px;
  border-radius: 4px;
}

.footer-column h4 {
  color: var(--color-white);
  font-size: 0.875rem;
  font-weight: 600;
  margin-bottom: 16px;
  letter-spacing: 0.02em;
}

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

.footer-column ul li a {
  color: var(--color-gray-400);
  font-size: 0.8125rem;
  transition: var(--transition);
}

.footer-column ul li a:hover {
  color: var(--color-white);
}

.footer-bottom {
  padding: 20px 0;
  text-align: center;
  color: var(--color-gray-500);
  font-size: 0.8125rem;
}

/* ============================================
   Animations
   ============================================ */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

.animate-fade-in-up {
  animation: fadeInUp 0.5s ease forwards;
}

.animate-fade-in {
  animation: fadeIn 0.5s ease forwards;
}

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

/* Scroll reveal */
.reveal {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.5s ease, transform 0.5s ease;
}

.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

/* Back to top button */
.back-to-top {
  position: fixed;
  bottom: 32px;
  right: 32px;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--color-primary);
  color: var(--color-white);
  border: none;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--shadow-lg);
  opacity: 0;
  visibility: hidden;
  transform: translateY(10px);
  transition: opacity 0.3s ease, visibility 0.3s ease, transform 0.3s ease, background 0.2s ease;
  z-index: 999;
}

.back-to-top.visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.back-to-top:hover {
  background: var(--color-primary-dark);
  transform: translateY(-2px);
}

/* ============================================
   Responsive Design
   ============================================ */
@media (max-width: 1024px) {
  h1 { font-size: 2.5rem; }
  h2 { font-size: 1.75rem; }
  
  .grid-4 {
    grid-template-columns: repeat(2, 1fr);
  }
  
  .grid-5 {
    grid-template-columns: repeat(3, 1fr);
  }
  
  .footer-grid {
    grid-template-columns: 1fr 1fr;
    gap: 32px;
  }
}

@media (max-width: 768px) {
  h1 { font-size: 2rem; }
  h2 { font-size: 1.5rem; }
  h3 { font-size: 1.25rem; }
  
  .section {
    padding: 64px 0;
  }
  
  .section-header {
    margin-bottom: 40px;
  }
  
  .header-nav {
    display: none;
    position: fixed;
    top: var(--header-height);
    left: 0;
    right: 0;
    background: var(--color-white);
    flex-direction: column;
    padding: 20px;
    gap: 12px;
    border-bottom: 1px solid var(--color-gray-200);
  }
  
  .header-nav.active {
    display: flex;
  }
  
  .menu-toggle {
    display: flex;
  }
  
  .grid-2,
  .grid-3,
  .grid-4,
  .grid-5 {
    grid-template-columns: 1fr;
  }
  
  .footer-grid {
    grid-template-columns: 1fr;
    gap: 28px;
  }
  
  .btn-lg {
    padding: 12px 24px;
    font-size: 0.9375rem;
  }
}

@media (max-width: 480px) {
  h1 { font-size: 1.75rem; }
  h2 { font-size: 1.375rem; }
  
  .container {
    padding: 0 16px;
  }
  
  .section {
    padding: 48px 0;
  }
  
  .card {
    padding: 20px;
  }
}