/* {{RIPER-5:
  Action: "Added"
  Task_ID: "#1"
  Timestamp: "2025-12-31"
  Authoring_Role: "LD"
  Principle_Applied: "Aether-Design-Liquid-Glass, Aether-Design-Universal-Softness, Aether-Engineering-DRY"
  Quality_Check: "遵循玻璃效果、统一圆角(rounded-2xl/rounded-full)、流体动画原则"
}} */

/* ========================================
   DOCFLUX.TECH - LIQUID GLASS DESIGN SYSTEM
   ======================================== */

/* === ROOT VARIABLES === */
:root {
  /* Color Palette - Tech Blue & Purple Gradient */
  --primary: #6366f1;
  --primary-dark: #4f46e5;
  --secondary: #8b5cf6;
  --accent: #06b6d4;
  --success: #10b981;
  --warning: #f59e0b;
  --danger: #ef4444;
  
  /* Neutral Colors */
  --bg-base: #0f172a;
  --bg-elevated: #1e293b;
  --text-primary: #f1f5f9;
  --text-secondary: #cbd5e1;
  --text-muted: #94a3b8;
  
  /* Glass Effect Variables */
  --glass-bg: rgba(255, 255, 255, 0.05);
  --glass-border: rgba(255, 255, 255, 0.1);
  --glass-blur: 20px;
  
  /* Border Radius - ONLY TWO VALUES */
  --radius-soft: 1rem; /* rounded-2xl equivalent */
  --radius-full: 9999px; /* rounded-full */
  
  /* Shadows */
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.1);
  --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.2);
  --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.3);
  --shadow-glow: 0 0 24px rgba(99, 102, 241, 0.3);
  
  /* Transitions - Physics-based cubic-bezier */
  --ease-smooth: cubic-bezier(0.4, 0.0, 0.2, 1);
  --ease-bounce: cubic-bezier(0.68, -0.55, 0.265, 1.55);
  --duration-fast: 150ms;
  --duration-normal: 300ms;
  --duration-slow: 500ms;
}

/* === RESET & BASE === */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Inter', 'Helvetica Neue', Arial, sans-serif;
  background: linear-gradient(135deg, var(--bg-base) 0%, #1a1f3a 100%);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  overflow-x: hidden;
  position: relative;
}

/* Animated Background Gradient */
body::before {
  content: '';
  position: fixed;
  top: -50%;
  left: -50%;
  width: 200%;
  height: 200%;
  background: radial-gradient(circle at 20% 50%, rgba(99, 102, 241, 0.1) 0%, transparent 50%),
              radial-gradient(circle at 80% 80%, rgba(139, 92, 246, 0.1) 0%, transparent 50%),
              radial-gradient(circle at 40% 90%, rgba(6, 182, 212, 0.1) 0%, transparent 50%);
  animation: bgShift 20s ease infinite;
  pointer-events: none;
  z-index: -1;
}

@keyframes bgShift {
  0%, 100% { transform: translate(0, 0) rotate(0deg); }
  50% { transform: translate(5%, 5%) rotate(5deg); }
}

/* === GLASS COMPONENTS === */
.glass {
  background: var(--glass-bg);
  backdrop-filter: blur(var(--glass-blur)) saturate(150%) brightness(1.1);
  -webkit-backdrop-filter: blur(var(--glass-blur)) saturate(150%) brightness(1.1);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-soft);
  box-shadow: var(--shadow-md);
}

.glass-strong {
  background: rgba(255, 255, 255, 0.08);
  backdrop-filter: blur(30px) saturate(180%) brightness(1.2);
  -webkit-backdrop-filter: blur(30px) saturate(180%) brightness(1.2);
  border: 1px solid rgba(255, 255, 255, 0.15);
  border-radius: var(--radius-soft);
}

/* === NAVIGATION === */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  padding: 1rem 0;
  transition: all var(--duration-normal) var(--ease-smooth);
}

.navbar.scrolled {
  background: rgba(15, 23, 42, 0.8);
  backdrop-filter: blur(20px);
  box-shadow: var(--shadow-md);
}

.nav-container {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 2rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  font-size: 1.5rem;
  font-weight: 700;
  background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  text-decoration: none;
  transition: transform var(--duration-fast) var(--ease-smooth);
}

.logo:hover {
  transform: scale(1.05);
}

.nav-menu {
  display: flex;
  gap: 2rem;
  list-style: none;
  align-items: center;
}

.nav-link {
  color: var(--text-secondary);
  text-decoration: none;
  font-weight: 500;
  transition: color var(--duration-fast) var(--ease-smooth);
  position: relative;
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--primary), var(--secondary));
  border-radius: var(--radius-full);
  transition: width var(--duration-normal) var(--ease-smooth);
}

.nav-link:hover {
  color: var(--text-primary);
}

.nav-link:hover::after {
  width: 100%;
}

.nav-link.active {
  color: var(--primary);
}

/* Mobile Menu Toggle */
.menu-toggle {
  display: none;
  flex-direction: column;
  gap: 6px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
}

.menu-toggle span {
  width: 28px;
  height: 3px;
  background: var(--text-primary);
  border-radius: var(--radius-full);
  transition: all var(--duration-normal) var(--ease-smooth);
}

/* === BUTTONS === */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.75rem 1.5rem;
  font-weight: 600;
  text-decoration: none;
  border: none;
  border-radius: var(--radius-soft); /* ENFORCED */
  cursor: pointer;
  transition: all var(--duration-normal) var(--ease-smooth);
  position: relative;
  overflow: hidden;
}

.btn::before {
  content: '';
  position: absolute;
  top: 50%;
  left: 50%;
  width: 0;
  height: 0;
  border-radius: var(--radius-full);
  background: rgba(255, 255, 255, 0.2);
  transform: translate(-50%, -50%);
  transition: width var(--duration-slow) var(--ease-smooth),
              height var(--duration-slow) var(--ease-smooth);
}

.btn:hover::before {
  width: 300px;
  height: 300px;
}

.btn-primary {
  background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
  color: white;
  box-shadow: var(--shadow-md);
}

.btn-primary:hover {
  box-shadow: var(--shadow-glow);
  transform: translateY(-2px);
}

.btn-secondary {
  background: var(--glass-bg);
  color: var(--text-primary);
  border: 1px solid var(--glass-border);
  backdrop-filter: blur(10px);
}

.btn-secondary:hover {
  background: rgba(255, 255, 255, 0.1);
  border-color: var(--primary);
}

/* === HERO SECTION === */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 6rem 2rem 4rem;
  position: relative;
  overflow: hidden;
}

.hero-content {
  max-width: 1280px;
  text-align: center;
  z-index: 1;
}

.hero-title {
  font-size: clamp(2.5rem, 8vw, 5rem);
  font-weight: 800;
  line-height: 1.1;
  margin-bottom: 1.5rem;
  background: linear-gradient(135deg, #fff 0%, var(--primary) 50%, var(--secondary) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  animation: fadeInUp 0.8s var(--ease-smooth);
}

.hero-subtitle {
  font-size: clamp(1.125rem, 3vw, 1.5rem);
  color: var(--text-secondary);
  margin-bottom: 3rem;
  max-width: 700px;
  margin-left: auto;
  margin-right: auto;
  animation: fadeInUp 0.8s var(--ease-smooth) 0.2s both;
}

.hero-cta {
  display: flex;
  gap: 1rem;
  justify-content: center;
  flex-wrap: wrap;
  animation: fadeInUp 0.8s var(--ease-smooth) 0.4s both;
}

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

/* === CARDS === */
.card {
  background: var(--glass-bg);
  backdrop-filter: blur(var(--glass-blur)) saturate(150%) brightness(1.1);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-soft); /* ENFORCED */
  padding: 2rem;
  transition: all var(--duration-normal) var(--ease-smooth);
  position: relative;
  overflow: hidden;
}

.card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--primary), var(--secondary), var(--accent));
  transform: scaleX(0);
  transition: transform var(--duration-normal) var(--ease-smooth);
}

.card:hover::before {
  transform: scaleX(1);
}

.card:hover {
  transform: translateY(-8px);
  box-shadow: var(--shadow-lg), var(--shadow-glow);
  border-color: var(--primary);
}

.card-icon {
  width: 60px;
  height: 60px;
  border-radius: var(--radius-soft);
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  margin-bottom: 1.5rem;
  box-shadow: var(--shadow-glow);
}

.card-title {
  font-size: 1.5rem;
  font-weight: 700;
  margin-bottom: 1rem;
  color: var(--text-primary);
}

.card-description {
  color: var(--text-secondary);
  line-height: 1.7;
}

/* === SECTIONS === */
.section {
  padding: 5rem 2rem;
  position: relative;
}

.container {
  max-width: 1280px;
  margin: 0 auto;
}

.section-header {
  text-align: center;
  margin-bottom: 4rem;
}

.section-title {
  font-size: clamp(2rem, 5vw, 3rem);
  font-weight: 800;
  margin-bottom: 1rem;
  background: linear-gradient(135deg, var(--text-primary) 0%, var(--primary) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.section-subtitle {
  font-size: 1.25rem;
  color: var(--text-secondary);
  max-width: 600px;
  margin: 0 auto;
}

/* === GRID LAYOUTS === */
.grid {
  display: grid;
  gap: 2rem;
}

.grid-2 {
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
}

.grid-3 {
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
}

.grid-4 {
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
}

/* === PRICING CARDS === */
.pricing-card {
  background: var(--glass-bg);
  backdrop-filter: blur(var(--glass-blur)) saturate(150%) brightness(1.1);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-soft);
  padding: 2.5rem;
  text-align: center;
  transition: all var(--duration-normal) var(--ease-smooth);
}

.pricing-card.featured {
  border: 2px solid var(--primary);
  box-shadow: var(--shadow-glow);
  transform: scale(1.05);
}

.pricing-card:hover {
  transform: translateY(-8px) scale(1.02);
  box-shadow: var(--shadow-lg);
}

.pricing-badge {
  display: inline-block;
  padding: 0.5rem 1rem;
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  color: white;
  border-radius: var(--radius-full); /* ENFORCED */
  font-size: 0.875rem;
  font-weight: 600;
  margin-bottom: 1rem;
}

.pricing-plan {
  font-size: 1.5rem;
  font-weight: 700;
  margin-bottom: 1rem;
}

.pricing-price {
  font-size: 3rem;
  font-weight: 800;
  color: var(--primary);
  margin-bottom: 0.5rem;
}

.pricing-price span {
  font-size: 1.25rem;
  color: var(--text-secondary);
}

.pricing-features {
  list-style: none;
  margin: 2rem 0;
  text-align: left;
}

.pricing-features li {
  padding: 0.75rem 0;
  color: var(--text-secondary);
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.pricing-features li::before {
  content: '✓';
  color: var(--success);
  font-weight: 700;
  font-size: 1.25rem;
}

/* === FORMS === */
.form-group {
  margin-bottom: 1.5rem;
}

.form-label {
  display: block;
  margin-bottom: 0.5rem;
  font-weight: 600;
  color: var(--text-primary);
}

.form-input,
.form-textarea {
  width: 100%;
  padding: 0.875rem 1.25rem;
  background: var(--glass-bg);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-soft); /* ENFORCED */
  color: var(--text-primary);
  font-size: 1rem;
  transition: all var(--duration-normal) var(--ease-smooth);
  backdrop-filter: blur(10px);
}

.form-input:focus,
.form-textarea:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.2);
}

.form-textarea {
  min-height: 150px;
  resize: vertical;
}

/* === FOOTER === */
.footer {
  background: rgba(15, 23, 42, 0.8);
  backdrop-filter: blur(20px);
  padding: 3rem 2rem 1.5rem;
  border-top: 1px solid var(--glass-border);
}

.footer-content {
  max-width: 1280px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 3rem;
  margin-bottom: 2rem;
}

.footer-section h3 {
  margin-bottom: 1rem;
  color: var(--text-primary);
}

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

.footer-links li {
  margin-bottom: 0.75rem;
}

.footer-links a {
  color: var(--text-secondary);
  text-decoration: none;
  transition: color var(--duration-fast) var(--ease-smooth);
}

.footer-links a:hover {
  color: var(--primary);
}

.footer-bottom {
  max-width: 1280px;
  margin: 0 auto;
  padding-top: 2rem;
  border-top: 1px solid var(--glass-border);
  text-align: center;
  color: var(--text-muted);
}

/* === BADGES === */
.badge {
  display: inline-block;
  padding: 0.375rem 0.875rem;
  background: var(--glass-bg);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-full); /* ENFORCED */
  font-size: 0.875rem;
  font-weight: 600;
}

/* === AVATARS === */
.avatar {
  width: 48px;
  height: 48px;
  border-radius: var(--radius-full); /* ENFORCED */
  object-fit: cover;
  border: 2px solid var(--glass-border);
}

/* === RESPONSIVE === */
@media (max-width: 768px) {
  .nav-menu {
    position: fixed;
    top: 70px;
    left: -100%;
    width: 80%;
    max-width: 300px;
    height: calc(100vh - 70px);
    background: rgba(15, 23, 42, 0.95);
    backdrop-filter: blur(20px);
    flex-direction: column;
    align-items: flex-start;
    padding: 2rem;
    border-right: 1px solid var(--glass-border);
    transition: left var(--duration-normal) var(--ease-smooth);
    box-shadow: var(--shadow-lg);
  }
  
  .nav-menu.active {
    left: 0;
  }
  
  .menu-toggle {
    display: flex;
  }
  
  .menu-toggle.active span:nth-child(1) {
    transform: rotate(45deg) translate(8px, 8px);
  }
  
  .menu-toggle.active span:nth-child(2) {
    opacity: 0;
  }
  
  .menu-toggle.active span:nth-child(3) {
    transform: rotate(-45deg) translate(7px, -7px);
  }
  
  .hero-cta {
    flex-direction: column;
  }
  
  .btn {
    width: 100%;
  }
}

/* === UTILITY CLASSES === */
.text-center { text-align: center; }
.text-gradient {
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.mt-3 { margin-top: 1.5rem; }
.mt-4 { margin-top: 2rem; }
.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }
.mb-4 { margin-bottom: 2rem; }