/* 51Talk Promotional Landing Page - Main Stylesheet */
/* Mobile-First Responsive Design */

/* CSS Custom Properties (CSS Variables) */
:root {
  /* 51Talk Brand Colors - Enhanced for Activity */
  --primary-yellow: #FFD700;
  --primary-blue: #FF6B35; /* 改为更活泼的橙红色 */
  --secondary-blue: #FF5722;
  --accent-yellow: #FFA500;
  --accent-blue: #4FC3F7;

  /* Neutral Colors */
  --white: #FFFFFF;
  --black: #000000;
  --gray-100: #F8F9FA;
  --gray-200: #E9ECEF;
  --gray-300: #DEE2E6;
  --gray-400: #CED4DA;
  --gray-500: #ADB5BD;
  --gray-600: #6C757D;
  --gray-700: #495057;
  --gray-800: #343A40;
  --gray-900: #212529;

  /* Status Colors */
  --success: #28A745;
  --warning: #FFC107;
  --error: #DC3545;
  --info: #17A2B8;

  /* Typography */
  --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', 'Helvetica Neue', Helvetica, Arial, sans-serif;
  --font-size-xs: 0.75rem;    /* 12px */
  --font-size-sm: 0.875rem;   /* 14px */
  --font-size-base: 1rem;     /* 16px */
  --font-size-lg: 1.125rem;   /* 18px */
  --font-size-xl: 1.25rem;    /* 20px */
  --font-size-2xl: 1.5rem;    /* 24px */
  --font-size-3xl: 1.875rem;  /* 30px */
  --font-size-4xl: 2.25rem;   /* 36px */
  --font-size-5xl: 3rem;      /* 48px */

  /* Spacing */
  --spacing-xs: 0.25rem;   /* 4px */
  --spacing-sm: 0.5rem;    /* 8px */
  --spacing-md: 0.75rem;   /* 12px */
  --spacing-lg: 1rem;      /* 16px */
  --spacing-xl: 1.5rem;    /* 24px */
  --spacing-2xl: 2rem;     /* 32px */
  --spacing-3xl: 3rem;     /* 48px */
  --spacing-4xl: 4rem;     /* 64px */

  /* Border Radius */
  --radius-sm: 0.25rem;    /* 4px */
  --radius-md: 0.5rem;     /* 8px */
  --radius-lg: 0.75rem;    /* 12px */
  --radius-xl: 1rem;       /* 16px */
  --radius-2xl: 1.5rem;    /* 24px */

  /* 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-normal: 300ms ease-in-out;
  --transition-slow: 500ms ease-in-out;

  /* Z-index */
  --z-dropdown: 1000;
  --z-modal-backdrop: 1040;
  --z-modal: 1050;
  --z-toast: 1060;
  --z-tooltip: 1070;
}

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

html {
  font-size: 16px;
  line-height: 1.5;
  -webkit-text-size-adjust: 100%;
  -ms-text-size-adjust: 100%;
}

body {
  font-family: var(--font-family);
  font-size: var(--font-size-base);
  line-height: 1.6;
  color: var(--gray-800);
  background: linear-gradient(135deg, #FFE5B4 0%, #FFF9E6 25%, #E8F5FF 75%, #F0F8FF 100%);
  background-attachment: fixed;
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  position: relative;
}

/* 添加背景装饰元素 */
body::before {
  content: '';
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-image:
    radial-gradient(circle at 20% 20%, rgba(255, 215, 0, 0.1) 0%, transparent 50%),
    radial-gradient(circle at 80% 80%, rgba(79, 195, 247, 0.1) 0%, transparent 50%),
    radial-gradient(circle at 40% 70%, rgba(255, 165, 0, 0.05) 0%, transparent 40%);
  z-index: -1;
  pointer-events: none;
}


/* Main Container */
.container {
  max-width: 100%;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  position: relative;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
  font-weight: 600;
  line-height: 1.3;
  margin-bottom: var(--spacing-lg);
  color: var(--gray-900);
}

h1 { font-size: var(--font-size-3xl); }
h2 { font-size: var(--font-size-2xl); }
h3 { font-size: var(--font-size-xl); }
h4 { font-size: var(--font-size-lg); }

p {
  margin-bottom: var(--spacing-lg);
}

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

a:hover {
  color: var(--secondary-blue);
  text-decoration: underline;
}

/* Buttons Base Styles */
button {
  font-family: inherit;
  font-size: var(--font-size-base);
  line-height: 1.5;
  border: none;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all var(--transition-fast);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-sm);
  text-align: center;
  text-decoration: none;
  background: none;
  padding: 0;
  margin: 0;
}

button:focus {
  outline: 2px solid var(--primary-blue);
  outline-offset: 2px;
}

button:disabled {
  cursor: not-allowed;
  opacity: 0.6;
}

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

/* Accessibility */
@media (prefers-reduced-motion: reduce) {
  * {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

/* Screen reader only content */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* Header Banner */
.header-banner {
  background: linear-gradient(135deg, #FF6B35 0%, #FFA500 50%, #FF5722 100%);
  color: var(--white);
  padding: var(--spacing-3xl) var(--spacing-lg);
  text-align: center;
  position: relative;
  overflow: hidden;
  box-shadow: 0 10px 30px rgba(255, 107, 53, 0.3);
}

/* 添加动态背景元素 */
.header-banner::before {
  content: '🎉📚🌟🎯🏆';
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  font-size: 120px;
  opacity: 0.05;
  letter-spacing: 30px;
  animation: float 6s ease-in-out infinite;
}

@keyframes float {
  0%, 100% { transform: translate(-50%, -50%) rotate(0deg); }
  50% { transform: translate(-50%, -60%) rotate(5deg); }
}

.banner-content {
  position: relative;
  z-index: 2;
  max-width: 800px;
  margin: 0 auto;
}

.logo {
  width: 120px;
  height: auto;
  margin: 0 auto var(--spacing-xl);
  filter: drop-shadow(0 4px 8px rgba(0, 0, 0, 0.3));
  transition: transform 0.3s ease;
}

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

.main-title {
  font-size: var(--font-size-3xl);
  font-weight: 800;
  margin-bottom: var(--spacing-md);
  text-shadow: 0 4px 8px rgba(0, 0, 0, 0.4);
  animation: titleGlow 2s ease-in-out infinite alternate;
}

@keyframes titleGlow {
  from { text-shadow: 0 4px 8px rgba(0, 0, 0, 0.4); }
  to { text-shadow: 0 4px 12px rgba(255, 215, 0, 0.6); }
}

.subtitle {
  font-size: var(--font-size-xl);
  font-weight: 600;
  opacity: 0.95;
  margin-bottom: 0;
  animation: subtitleBounce 1s ease-in-out infinite;
}

@keyframes subtitleBounce {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-2px); }
}

.banner-decoration {
  position: absolute;
  top: -20px;
  right: -20px;
  width: 150px;
  height: 150px;
  background: radial-gradient(circle, var(--accent-yellow) 0%, transparent 70%);
  opacity: 0.3;
  border-radius: 50%;
  animation: bounce 3s ease-in-out infinite;
}

.banner-decoration::after {
  content: '';
  position: absolute;
  bottom: -20px;
  left: -20px;
  width: 100px;
  height: 100px;
  background: radial-gradient(circle, var(--accent-blue) 0%, transparent 70%);
  opacity: 0.3;
  border-radius: 50%;
  animation: bounce 3s ease-in-out infinite reverse;
}

@keyframes bounce {
  0%, 100% { transform: translateY(0) rotate(0deg); }
  50% { transform: translateY(-10px) rotate(10deg); }
}

/* Value Proposition Section */
.value-section {
  padding: var(--spacing-2xl) var(--spacing-lg);
  background: linear-gradient(135deg, rgba(255, 255, 255, 0.95) 0%, rgba(240, 248, 255, 0.95) 100%);
  border-bottom: 3px solid var(--accent-yellow);
  position: relative;
  overflow: hidden;
}

.value-section::before {
  content: '';
  position: absolute;
  top: -50%;
  right: -10%;
  width: 200px;
  height: 200px;
  background: radial-gradient(circle, rgba(255, 215, 0, 0.1) 0%, transparent 70%);
  border-radius: 50%;
  animation: float 8s ease-in-out infinite;
}

.value-content {
  max-width: 800px;
  margin: 0 auto;
  text-align: center;
  position: relative;
  z-index: 2;
}

.value-title {
  font-size: var(--font-size-2xl);
  font-weight: 800;
  color: #FF6B35;
  margin-bottom: var(--spacing-2xl);
  text-shadow: 2px 2px 4px rgba(255, 107, 53, 0.2);
  position: relative;
}

.value-title::after {
  content: '✨';
  position: absolute;
  top: -10px;
  right: -30px;
  font-size: var(--font-size-xl);
  animation: sparkle 1.5s ease-in-out infinite;
}

@keyframes sparkle {
  0%, 100% { transform: scale(1) rotate(0deg); }
  50% { transform: scale(1.2) rotate(180deg); }
}

.value-points {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--spacing-lg);
  margin-bottom: 0;
}

.value-point {
  display: flex;
  align-items: center;
  text-align: left;
  gap: var(--spacing-lg);
  padding: var(--spacing-lg);
  background: rgba(255, 255, 255, 0.8);
  border-radius: var(--radius-lg);
  border-left: 4px solid var(--accent-yellow);
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
  transition: all var(--transition-normal);
  position: relative;
  overflow: hidden;
}

.value-point::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 0;
  height: 100%;
  background: linear-gradient(90deg, rgba(255, 215, 0, 0.1) 0%, transparent 100%);
  transition: width var(--transition-normal);
}

.value-point:hover {
  transform: translateX(8px);
  box-shadow: 0 8px 25px rgba(255, 107, 53, 0.2);
  border-left-color: #FF6B35;
}

.value-point:hover::before {
  width: 100%;
}

.value-icon {
  font-size: var(--font-size-3xl);
  flex-shrink: 0;
  width: 60px;
  text-align: center;
  animation: iconBounce 2s ease-in-out infinite;
  animation-delay: calc(var(--animation-delay) * 0.5s);
}

.value-point:nth-child(1) .value-icon { --animation-delay: 0; }
.value-point:nth-child(2) .value-icon { --animation-delay: 1; }
.value-point:nth-child(3) .value-icon { --animation-delay: 2; }
.value-point:nth-child(4) .value-icon { --animation-delay: 3; }

@keyframes iconBounce {
  0%, 100% { transform: translateY(0) rotate(0deg); }
  25% { transform: translateY(-5px) rotate(5deg); }
  75% { transform: translateY(2px) rotate(-5deg); }
}

.value-point p {
  font-size: var(--font-size-lg);
  font-weight: 600;
  margin-bottom: 0;
  line-height: 1.4;
  color: var(--gray-800);
  position: relative;
  z-index: 2;
}


/* Version Selection Section */
.selection-section {
  padding: var(--spacing-2xl) var(--spacing-lg) calc(var(--spacing-2xl) + 120px);
  background: linear-gradient(135deg, #FFF9E6 0%, #F0F8FF 50%, #E6F3FF 100%);
  flex: 1;
  position: relative;
}

.selection-section::before {
  content: '📚';
  position: absolute;
  top: 20px;
  right: 20px;
  font-size: 40px;
  opacity: 0.1;
  animation: float 6s ease-in-out infinite;
}

.selection-section::after {
  content: '🎯';
  position: absolute;
  bottom: 20px;
  left: 20px;
  font-size: 40px;
  opacity: 0.1;
  animation: float 8s ease-in-out infinite reverse;
}

.selection-title {
  font-size: var(--font-size-2xl);
  font-weight: 800;
  color: #FF6B35;
  text-align: center;
  margin-bottom: var(--spacing-2xl);
  text-shadow: 2px 2px 4px rgba(255, 107, 53, 0.1);
  position: relative;
}

.selection-title::before {
  content: '👆';
  position: absolute;
  top: -10px;
  left: -30px;
  font-size: var(--font-size-xl);
  animation: point 2s ease-in-out infinite;
}

@keyframes point {
  0%, 100% { transform: translateX(0); }
  50% { transform: translateX(10px); }
}

.selection-hint {
  text-align: center;
  margin-top: var(--spacing-2xl);
  padding: var(--spacing-xl);
  background: linear-gradient(135deg, rgba(255, 215, 0, 0.2) 0%, rgba(255, 107, 53, 0.1) 100%);
  color: var(--gray-800);
  border-radius: var(--radius-lg);
  border: 2px solid var(--accent-yellow);
  position: relative;
  overflow: hidden;
}

.selection-hint::before {
  content: '💡';
  position: absolute;
  top: 50%;
  left: 20px;
  transform: translateY(-50%);
  font-size: var(--font-size-2xl);
  animation: glow 2s ease-in-out infinite;
}

@keyframes glow {
  0%, 100% { opacity: 0.6; transform: translateY(-50%) scale(1); }
  50% { opacity: 1; transform: translateY(-50%) scale(1.1); }
}

.selection-hint p {
  margin-bottom: 0;
  font-weight: 600;
  font-size: var(--font-size-lg);
  margin-left: 40px;
}

/* Footer */
.footer {
  background: linear-gradient(135deg, var(--gray-900) 0%, var(--gray-800) 100%);
  color: var(--white);
  padding: var(--spacing-3xl) var(--spacing-lg) var(--spacing-2xl);
  text-align: center;
  margin-top: auto;
  position: relative;
  border-top: 3px solid var(--accent-yellow);
  box-shadow: 0 -10px 30px rgba(0, 0, 0, 0.1);
}

.footer-content {
  max-width: 800px;
  margin: 0 auto;
  position: relative;
  z-index: 2;
}

.footer::before {
  content: '🌟⭐✨';
  position: absolute;
  top: 20px;
  left: 50%;
  transform: translateX(-50%);
  font-size: 24px;
  letter-spacing: 20px;
  opacity: 0.3;
  animation: sparkle 3s ease-in-out infinite;
}

@keyframes sparkle {
  0%, 100% { opacity: 0.3; transform: translateX(-50%) scale(1); }
  50% { opacity: 0.6; transform: translateX(-50%) scale(1.1); }
}

.footer-logo {
  width: 100px;
  height: auto;
  margin: 0 auto var(--spacing-lg);
  opacity: 0.9;
  transition: all var(--transition-normal);
  background: var(--white);
  padding: 10px;
  border-radius: var(--radius-lg);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
}

.footer-logo:hover {
  opacity: 1;
  transform: scale(1.05);
}

.copyright {
  font-size: var(--font-size-base);
  color: var(--gray-300);
  margin-bottom: var(--spacing-sm);
  font-weight: 600;
}

.company-info {
  font-size: var(--font-size-base);
  color: var(--gray-400);
  margin-bottom: 0;
  font-weight: 500;
  padding: var(--spacing-lg);
  background: rgba(255, 255, 255, 0.05);
  border-radius: var(--radius-lg);
  border: 1px solid rgba(255, 255, 255, 0.1);
  margin-top: var(--spacing-lg);
}

/* Responsive Design */

/* Small tablets (576px and up) */
@media (min-width: 576px) {
  .value-points {
    grid-template-columns: repeat(2, 1fr);
    gap: var(--spacing-xl);
  }

  .main-title {
    font-size: var(--font-size-4xl);
  }

  .selection-title,
  .value-title {
    font-size: var(--font-size-3xl);
  }
}

/* Tablets (768px and up) */
@media (min-width: 768px) {
  html {
    font-size: 18px;
  }

  .header-banner {
    padding: var(--spacing-4xl) var(--spacing-xl);
  }

  .value-section,
  .selection-section {
    padding: var(--spacing-4xl) var(--spacing-xl);
  }

  .value-points {
    grid-template-columns: repeat(2, 1fr);
    gap: var(--spacing-2xl);
  }

  .logo {
    width: 150px;
  }

  .footer-logo {
    width: 100px;
  }
}

/* Desktop (992px and up) */
@media (min-width: 992px) {
  .value-points {
    grid-template-columns: repeat(4, 1fr);
    gap: var(--spacing-xl);
  }

  .value-point {
    flex-direction: column;
    text-align: center;
  }

  .value-icon {
    width: auto;
  }
}

/* Large Desktop (1200px and up) */
@media (min-width: 1200px) {
  .container {
    max-width: 1200px;
    margin: 0 auto;
    box-shadow: var(--shadow-xl);
  }

  .header-banner {
    border-radius: var(--radius-xl) var(--radius-xl) 0 0;
  }

  .footer {
    border-radius: 0 0 var(--radius-xl) var(--radius-xl);
  }
}

/* Print Styles */
@media print {
  * {
    background: transparent !important;
    color: black !important;
    box-shadow: none !important;
    text-shadow: none !important;
  }

  .claim-button-container,
  .modal,
  .toast,
  .restriction-notice {
    display: none !important;
  }

  .header-banner {
    background: var(--gray-200) !important;
    color: var(--black) !important;
  }
}