/* SeoCraft Website - Global Styles */
/* Version: 1.0.0 */

/* ============================================
   CSS Variables (Design Tokens)
   ============================================ */
:root {
  /* Colors */
  --primary-color: #2563EB;
  --primary-dark: #1E40AF;
  --primary-light: #3B82F6;
  --secondary-color: #F97316;
  --secondary-dark: #EA580C;
  --background-color: #FFFFFF;
  --background-light: #F9FAFB;
  --text-primary: #1F2937;
  --text-secondary: #6B7280;
  --text-light: #9CA3AF;
  --border-color: #E5E7EB;
  --success-color: #10B981;
  --error-color: #EF4444;
  --warning-color: #F59E0B;

  /* Typography */
  --font-family-primary: 'Inter', 'PingFang SC', 'Microsoft YaHei', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-family-code: 'Fira Code', 'Monaco', monospace;

  /* Spacing */
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2rem;
  --spacing-2xl: 3rem;
  --spacing-3xl: 4rem;

  /* Border Radius */
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-xl: 16px;
  --radius-full: 9999px;

  /* Shadows */
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);

  /* Transitions */
  --transition-fast: 150ms ease-in-out;
  --transition-base: 300ms ease-in-out;
  --transition-slow: 500ms ease-in-out;
}

/* ============================================
   Reset & Base Styles
   ============================================ */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

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

body {
  font-family: var(--font-family-primary);
  font-size: 1rem;
  line-height: 1.6;
  color: var(--text-primary);
  background-color: var(--background-color);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* ============================================
   Typography
   ============================================ */
h1, h2, h3, h4, h5, h6 {
  font-weight: 700;
  line-height: 1.2;
  margin-bottom: var(--spacing-md);
  color: var(--text-primary);
}

h1 {
  font-size: 3rem;
  margin-bottom: var(--spacing-lg);
}

h2 {
  font-size: 2.25rem;
}

h3 {
  font-size: 1.5rem;
}

h4 {
  font-size: 1.25rem;
}

p {
  margin-bottom: var(--spacing-md);
  color: var(--text-secondary);
}

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

a:hover {
  color: var(--primary-dark);
}

/* ============================================
   Container & Layout
   ============================================ */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--spacing-lg);
}

.container-fluid {
  width: 100%;
  padding: 0 var(--spacing-lg);
}

.section {
  padding: var(--spacing-3xl) 0;
}

.section-sm {
  padding: var(--spacing-2xl) 0;
}

/* ============================================
   Header & Navigation
   ============================================ */
.header {
  background-color: var(--background-color);
  border-bottom: 1px solid var(--border-color);
  position: sticky;
  top: 0;
  z-index: 1000;
  box-shadow: var(--shadow-sm);
}

.navbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--spacing-md) 0;
}

.logo {
  display: flex;
  align-items: center;
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--primary-color);
}

.logo img {
  height: 40px;
  margin-right: var(--spacing-sm);
}

.nav-menu {
  display: flex;
  list-style: none;
  gap: var(--spacing-xl);
  align-items: center;
}

.nav-menu a {
  color: var(--text-primary);
  font-weight: 500;
  padding: var(--spacing-sm) 0;
  position: relative;
}

.nav-menu a::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background-color: var(--primary-color);
  transition: width var(--transition-base);
}

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

/* Language Switcher */
.lang-switcher {
  display: flex;
  gap: var(--spacing-sm);
  margin-left: var(--spacing-lg);
}

.lang-switcher a {
  padding: var(--spacing-xs) var(--spacing-sm);
  border-radius: var(--radius-md);
  font-size: 0.875rem;
  font-weight: 500;
}

.lang-switcher a.active {
  background-color: var(--primary-color);
  color: white;
}

/* Mobile Menu Toggle */
.menu-toggle {
  display: none;
  background: none;
  border: none;
  font-size: 1.5rem;
  cursor: pointer;
  color: var(--text-primary);
}

/* ============================================
   Buttons
   ============================================ */
.btn {
  display: inline-block;
  padding: var(--spacing-md) var(--spacing-xl);
  font-size: 1rem;
  font-weight: 600;
  text-align: center;
  border-radius: var(--radius-md);
  border: none;
  cursor: pointer;
  transition: all var(--transition-base);
  text-decoration: none;
}

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

.btn-primary:hover {
  background-color: var(--primary-dark);
  color: white;
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

.btn-secondary {
  background-color: transparent;
  color: var(--primary-color);
  border: 2px solid var(--primary-color);
}

.btn-secondary:hover {
  background-color: var(--primary-color);
  color: white;
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.btn-cta {
  background-color: var(--secondary-color);
  color: white;
  font-size: 1.125rem;
  padding: var(--spacing-lg) var(--spacing-2xl);
}

.btn-cta:hover {
  background-color: var(--secondary-dark);
  transform: translateY(-2px);
  box-shadow: var(--shadow-xl);
}

.btn-lg {
  padding: var(--spacing-lg) var(--spacing-2xl);
  font-size: 1.125rem;
}

.btn-sm {
  padding: var(--spacing-sm) var(--spacing-md);
  font-size: 0.875rem;
}

/* ============================================
   Hero Section
   ============================================ */
.hero {
  background: linear-gradient(135deg, var(--primary-color) 0%, var(--primary-dark) 100%);
  color: white;
  padding: var(--spacing-3xl) 0;
  text-align: center;
}

.hero h1 {
  color: white;
  font-size: 3.5rem;
  margin-bottom: var(--spacing-lg);
}

.hero p {
  font-size: 1.25rem;
  color: rgba(255, 255, 255, 0.9);
  margin-bottom: var(--spacing-2xl);
  max-width: 800px;
  margin-left: auto;
  margin-right: auto;
}

.hero-cta {
  display: flex;
  gap: var(--spacing-lg);
  justify-content: center;
  flex-wrap: wrap;
}

/* ============================================
   Features Grid
   ============================================ */
.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--spacing-xl);
  margin-top: var(--spacing-2xl);
}

.feature-card {
  background: white;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: var(--spacing-xl);
  text-align: center;
  box-shadow: var(--shadow-md);
  transition: all var(--transition-base);
}

.feature-card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-lg);
  border-color: var(--primary-color);
}

.feature-icon {
  width: 64px;
  height: 64px;
  margin: 0 auto var(--spacing-lg);
  background: linear-gradient(135deg, var(--primary-color), var(--primary-light));
  border-radius: var(--radius-lg);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2rem;
}

.feature-card h3 {
  margin-bottom: var(--spacing-md);
}

/* ============================================
   Pricing Table
   ============================================ */
.pricing-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--spacing-lg);
  margin-top: var(--spacing-2xl);
  max-width: 1400px;
  margin-left: auto;
  margin-right: auto;
}

.pricing-card {
  background: white;
  border: 2px solid var(--border-color);
  border-radius: var(--radius-xl);
  padding: var(--spacing-xl);
  text-align: center;
  box-shadow: var(--shadow-md);
  transition: all var(--transition-base);
  position: relative;
  transition: all var(--transition-base);
  display: flex;
  flex-direction: column;
  min-height: 100%;
}

.pricing-card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-xl);
  border-color: var(--primary-color);
}

.pricing-card.featured {
  border-color: var(--primary-color);
  box-shadow: var(--shadow-lg);
}

.pricing-card.featured::before {
  content: '推荐';
  position: absolute;
  top: -12px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--primary-color);
  color: white;
  padding: var(--spacing-xs) var(--spacing-lg);
  border-radius: var(--radius-full);
  font-size: 0.875rem;
  font-weight: 600;
}

.pricing-header {
  margin-bottom: var(--spacing-lg);
}

.pricing-header h3 {
  margin-bottom: var(--spacing-sm);
  font-size: 1.5rem;
  white-space: nowrap;
}

.pricing-price {
  font-size: 3rem;
  font-weight: 700;
  color: var(--primary-color);
  margin: var(--spacing-lg) 0;
}

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

.pricing-features {
  list-style: none;
  text-align: left;
  margin: var(--spacing-xl) 0;
  flex-grow: 1;
}

.pricing-features li {
  padding: var(--spacing-sm) 0;
  color: var(--text-secondary);
  font-size: 0.9rem;
  line-height: 1.5;
  word-break: break-word;
  overflow-wrap: break-word;
}

.pricing-features li::before {
  content: '✓';
  color: var(--success-color);
  font-weight: 700;
  margin-right: var(--spacing-sm);
}

/* ============================================
   Footer
   ============================================ */
.footer {
  background-color: var(--text-primary);
  color: white;
  padding: var(--spacing-3xl) 0 var(--spacing-xl);
  margin-top: var(--spacing-3xl);
}

.footer-content {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: var(--spacing-xl);
  margin-bottom: var(--spacing-xl);
}

.footer-section h4 {
  color: white;
  margin-bottom: var(--spacing-md);
}

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

.footer-section ul li {
  margin-bottom: var(--spacing-sm);
}

.footer-section a {
  color: rgba(255, 255, 255, 0.8);
  transition: color var(--transition-fast);
}

.footer-section a:hover {
  color: white;
}

.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  padding-top: var(--spacing-lg);
  text-align: center;
  color: rgba(255, 255, 255, 0.6);
}

/* ============================================
   Cards & Components
   ============================================ */
.card {
  background: white;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: var(--spacing-xl);
  box-shadow: var(--shadow-md);
  transition: all var(--transition-base);
}

.card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-lg);
  border-color: var(--primary-color);
}

.card-header {
  margin-bottom: var(--spacing-lg);
  padding-bottom: var(--spacing-md);
  border-bottom: 1px solid var(--border-color);
}

/* ============================================
   Forms
   ============================================ */
.form-group {
  margin-bottom: var(--spacing-lg);
}

.form-label {
  display: block;
  margin-bottom: var(--spacing-sm);
  font-weight: 500;
  color: var(--text-primary);
}

.form-input {
  width: 100%;
  padding: var(--spacing-md);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  font-size: 1rem;
  font-family: inherit;
  transition: border-color var(--transition-fast);
}

.form-input:focus {
  outline: none;
  border-color: var(--primary-color);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

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

/* ============================================
   Utilities
   ============================================ */
.text-center {
  text-align: center;
}

.text-left {
  text-align: left;
}

.text-right {
  text-align: right;
}

.mt-1 { margin-top: var(--spacing-sm); }
.mt-2 { margin-top: var(--spacing-md); }
.mt-3 { margin-top: var(--spacing-lg); }
.mt-4 { margin-top: var(--spacing-xl); }

.mb-1 { margin-bottom: var(--spacing-sm); }
.mb-2 { margin-bottom: var(--spacing-md); }
.mb-3 { margin-bottom: var(--spacing-lg); }
.mb-4 { margin-bottom: var(--spacing-xl); }

/* ============================================
   Responsive Design
   ============================================ */
@media (max-width: 768px) {
  html {
    font-size: 14px;
  }

  h1 {
    font-size: 2rem;
  }

  h2 {
    font-size: 1.75rem;
  }

  .hero h1 {
    font-size: 2.5rem;
  }

  .menu-toggle {
    display: block;
  }

  .nav-menu {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: white;
    flex-direction: column;
    padding: var(--spacing-lg);
    box-shadow: var(--shadow-lg);
    border-top: 1px solid var(--border-color);
  }

  .nav-menu.active {
    display: flex;
  }

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

  .pricing-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .hero-cta {
    flex-direction: column;
  }

  .hero-cta .btn {
    width: 100%;
  }

  .container {
    padding: 0 var(--spacing-md);
  }

  .section {
    padding: var(--spacing-2xl) 0;
  }
}

@media (max-width: 1024px) {
  .pricing-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  .pricing-grid {
    grid-template-columns: 1fr;
  }
  
  /* Download page: two columns to one column on mobile */
  [style*="grid-template-columns: 1fr 1fr"] {
    grid-template-columns: 1fr !important;
  }
}

@media (max-width: 480px) {
  .hero h1 {
    font-size: 2rem;
  }

  .pricing-price {
    font-size: 2rem;
  }
}