/* ========================================
   51吃瓜 App 官网 - 全局样式
   现代潮流设计：Glassmorphism + Gradient + Dark Mode
   ======================================== */

/* === CSS Variables === */
:root {
  --primary: #ff6b35;
  --primary-light: #ff8c5a;
  --primary-dark: #e55a2b;
  --secondary: #ffd700;
  --accent: #ff2d87;
  --bg-dark: #0a0a1a;
  --bg-card: rgba(255, 255, 255, 0.05);
  --bg-glass: rgba(255, 255, 255, 0.08);
  --text-primary: #ffffff;
  --text-secondary: rgba(255, 255, 255, 0.7);
  --text-muted: rgba(255, 255, 255, 0.4);
  --border-glass: rgba(255, 255, 255, 0.1);
  --gradient-main: linear-gradient(135deg, #ff6b35 0%, #ff2d87 50%, #7c3aed 100%);
  --gradient-warm: linear-gradient(135deg, #ff6b35 0%, #ffd700 100%);
  --gradient-cool: linear-gradient(135deg, #7c3aed 0%, #06b6d4 100%);
  --shadow-glow: 0 0 40px rgba(255, 107, 53, 0.3);
  --shadow-card: 0 8px 32px rgba(0, 0, 0, 0.3);
  --radius-sm: 8px;
  --radius-md: 16px;
  --radius-lg: 24px;
  --radius-xl: 32px;
  --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --font-main: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
}

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

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

body {
  font-family: var(--font-main);
  background: var(--bg-dark);
  color: var(--text-primary);
  line-height: 1.6;
  overflow-x: hidden;
  min-height: 100vh;
}

/* === Animated Background === */
body::before {
  content: '';
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: 
    radial-gradient(ellipse at 20% 20%, rgba(255, 107, 53, 0.15) 0%, transparent 50%),
    radial-gradient(ellipse at 80% 80%, rgba(124, 58, 237, 0.15) 0%, transparent 50%),
    radial-gradient(ellipse at 50% 50%, rgba(255, 45, 135, 0.08) 0%, transparent 50%);
  z-index: -1;
  animation: bgPulse 15s ease-in-out infinite alternate;
}

@keyframes bgPulse {
  0% { opacity: 0.8; }
  100% { opacity: 1; }
}

/* === Typography === */
h1, h2, h3, h4, h5, h6 {
  font-weight: 700;
  line-height: 1.2;
  letter-spacing: -0.02em;
}

h1 { font-size: clamp(2.5rem, 6vw, 4.5rem); }
h2 { font-size: clamp(2rem, 4vw, 3rem); }
h3 { font-size: clamp(1.25rem, 2.5vw, 1.75rem); }

p {
  color: var(--text-secondary);
  font-size: 1.05rem;
  line-height: 1.8;
}

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

/* === Utility Classes === */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

.section {
  padding: 100px 0;
  position: relative;
}

.section-header {
  text-align: center;
  margin-bottom: 64px;
}

.section-header h2 {
  background: var(--gradient-main);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: 16px;
}

.section-header p {
  max-width: 600px;
  margin: 0 auto;
  font-size: 1.1rem;
}

.gradient-text {
  background: var(--gradient-main);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* === Glass Card === */
.glass-card {
  background: var(--bg-glass);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border: 1px solid var(--border-glass);
  border-radius: var(--radius-lg);
  padding: 32px;
  transition: var(--transition);
}

.glass-card:hover {
  transform: translateY(-4px);
  border-color: rgba(255, 107, 53, 0.3);
  box-shadow: var(--shadow-glow);
}

/* === Buttons === */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 14px 32px;
  border-radius: 50px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  border: none;
  transition: var(--transition);
  text-decoration: none;
}

.btn-primary {
  background: var(--gradient-main);
  color: white;
  box-shadow: 0 4px 20px rgba(255, 107, 53, 0.4);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 30px rgba(255, 107, 53, 0.6);
}

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

.btn-secondary:hover {
  background: rgba(255, 255, 255, 0.15);
  border-color: var(--primary);
}

.btn-glow {
  animation: btnGlow 2s ease-in-out infinite alternate;
}

@keyframes btnGlow {
  0% { box-shadow: 0 4px 20px rgba(255, 107, 53, 0.4); }
  100% { box-shadow: 0 4px 40px rgba(255, 107, 53, 0.7); }
}

/* === Navigation === */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  padding: 16px 0;
  transition: var(--transition);
}

.navbar.scrolled {
  background: rgba(10, 10, 26, 0.9);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border-glass);
  padding: 12px 0;
}

.navbar .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.5rem;
  font-weight: 800;
}

.nav-logo .logo-icon {
  width: 40px;
  height: 40px;
  background: var(--gradient-main);
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 32px;
  list-style: none;
}

.nav-links a {
  color: var(--text-secondary);
  font-weight: 500;
  font-size: 0.95rem;
  position: relative;
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--gradient-main);
  transition: var(--transition);
}

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

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

.nav-cta .btn {
  padding: 10px 24px;
  font-size: 0.9rem;
}

/* Mobile Menu */
.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  padding: 8px;
}

.nav-toggle span {
  width: 24px;
  height: 2px;
  background: white;
  border-radius: 2px;
  transition: var(--transition);
}

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

.hero-content {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  align-items: center;
}

.hero-text h1 {
  margin-bottom: 24px;
}

.hero-text h1 .highlight {
  background: var(--gradient-warm);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-text p {
  font-size: 1.2rem;
  margin-bottom: 40px;
  max-width: 500px;
}

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

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

.phone-mockup {
  width: 280px;
  height: 560px;
  background: linear-gradient(145deg, #1a1a2e, #16213e);
  border-radius: 40px;
  border: 3px solid rgba(255, 255, 255, 0.1);
  position: relative;
  overflow: hidden;
  box-shadow: var(--shadow-card), var(--shadow-glow);
  animation: phoneFloat 6s ease-in-out infinite;
}

.phone-mockup::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 100%;
  background: var(--gradient-main);
  opacity: 0.1;
}

.phone-screen {
  position: absolute;
  top: 12px;
  left: 12px;
  right: 12px;
  bottom: 12px;
  border-radius: 30px;
  background: linear-gradient(180deg, #1a1a2e 0%, #0a0a1a 100%);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 20px;
}

.phone-screen .app-icon {
  width: 64px;
  height: 64px;
  background: var(--gradient-main);
  border-radius: 16px;
  margin-bottom: 16px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2rem;
}

.phone-screen .app-name {
  font-size: 1.2rem;
  font-weight: 700;
  margin-bottom: 8px;
}

@keyframes phoneFloat {
  0%, 100% { transform: translateY(0px) rotate(2deg); }
  50% { transform: translateY(-20px) rotate(-1deg); }
}

.hero-stats {
  display: flex;
  gap: 40px;
  margin-top: 48px;
}

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

.stat-number {
  font-size: 2rem;
  font-weight: 800;
  background: var(--gradient-warm);
  -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 Grid === */
.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 24px;
}

.feature-card {
  padding: 40px 32px;
  text-align: center;
}

.feature-icon {
  width: 72px;
  height: 72px;
  margin: 0 auto 24px;
  background: var(--bg-glass);
  border: 1px solid var(--border-glass);
  border-radius: 20px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2rem;
  transition: var(--transition);
}

.feature-card:hover .feature-icon {
  background: var(--gradient-main);
  border-color: transparent;
  transform: scale(1.1) rotate(5deg);
}

.feature-card h3 {
  margin-bottom: 12px;
  font-size: 1.25rem;
}

/* === How It Works === */
.steps-container {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 32px;
  position: relative;
}

.step-card {
  text-align: center;
  padding: 40px 24px;
  position: relative;
}

.step-number {
  width: 56px;
  height: 56px;
  background: var(--gradient-main);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  font-weight: 800;
  margin: 0 auto 24px;
}

/* === Testimonials === */
.testimonials-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 24px;
}

.testimonial-card {
  padding: 32px;
}

.testimonial-header {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 16px;
}

.testimonial-avatar {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: var(--gradient-main);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 1.1rem;
}

.testimonial-info h4 {
  font-size: 1rem;
  margin-bottom: 2px;
}

.testimonial-info span {
  font-size: 0.85rem;
  color: var(--text-muted);
}

.testimonial-stars {
  color: var(--secondary);
  margin-bottom: 12px;
}

/* === CTA Section === */
.cta-section {
  text-align: center;
  position: relative;
}

.cta-box {
  background: var(--bg-glass);
  backdrop-filter: blur(20px);
  border: 1px solid var(--border-glass);
  border-radius: var(--radius-xl);
  padding: 80px 40px;
  position: relative;
  overflow: hidden;
}

.cta-box::before {
  content: '';
  position: absolute;
  top: -50%;
  left: -50%;
  width: 200%;
  height: 200%;
  background: conic-gradient(from 0deg, transparent, rgba(255, 107, 53, 0.1), transparent, rgba(124, 58, 237, 0.1), transparent);
  animation: ctaRotate 10s linear infinite;
}

@keyframes ctaRotate {
  100% { transform: rotate(360deg); }
}

.cta-box h2 {
  position: relative;
  z-index: 1;
  margin-bottom: 16px;
}

.cta-box p {
  position: relative;
  z-index: 1;
  margin-bottom: 32px;
  max-width: 500px;
  margin-left: auto;
  margin-right: auto;
}

.cta-box .btn {
  position: relative;
  z-index: 1;
}

/* === Download Section === */
.download-options {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 24px;
  max-width: 900px;
  margin: 0 auto;
}

.download-card {
  text-align: center;
  padding: 48px 32px;
}

.download-card .platform-icon {
  font-size: 3rem;
  margin-bottom: 20px;
}

.download-card h3 {
  margin-bottom: 8px;
}

.download-card p {
  margin-bottom: 24px;
  font-size: 0.95rem;
}

/* === FAQ === */
.faq-list {
  max-width: 800px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.faq-item {
  background: var(--bg-glass);
  border: 1px solid var(--border-glass);
  border-radius: var(--radius-md);
  overflow: hidden;
  transition: var(--transition);
}

.faq-item.active {
  border-color: rgba(255, 107, 53, 0.3);
}

.faq-question {
  padding: 24px 32px;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-weight: 600;
  font-size: 1.05rem;
}

.faq-question:hover {
  color: var(--primary);
}

.faq-toggle {
  width: 24px;
  height: 24px;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: var(--transition);
  font-size: 1.2rem;
  color: var(--primary);
}

.faq-item.active .faq-toggle {
  transform: rotate(45deg);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.4s ease, padding 0.4s ease;
}

.faq-item.active .faq-answer {
  max-height: 300px;
}

.faq-answer p {
  padding: 0 32px 24px;
  font-size: 0.95rem;
  line-height: 1.8;
}

/* === About Page === */
.about-content {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  align-items: center;
}

.about-text h2 {
  margin-bottom: 24px;
}

.about-text p {
  margin-bottom: 16px;
}

.about-values {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 24px;
  margin-top: 64px;
}

.value-card {
  text-align: center;
  padding: 40px 24px;
}

.value-icon {
  font-size: 2.5rem;
  margin-bottom: 16px;
}

/* === Footer === */
.footer {
  border-top: 1px solid var(--border-glass);
  padding: 64px 0 32px;
  margin-top: 80px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 40px;
  margin-bottom: 48px;
}

.footer-brand p {
  margin-top: 12px;
  font-size: 0.9rem;
  max-width: 300px;
}

.footer-links h4 {
  font-size: 0.95rem;
  margin-bottom: 16px;
  color: var(--text-primary);
}

.footer-links ul {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.footer-links a {
  color: var(--text-muted);
  font-size: 0.9rem;
}

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

.footer-bottom {
  border-top: 1px solid var(--border-glass);
  padding-top: 24px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 16px;
}

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

.footer-social {
  display: flex;
  gap: 16px;
}

.footer-social a {
  width: 36px;
  height: 36px;
  background: var(--bg-glass);
  border: 1px solid var(--border-glass);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.9rem;
  transition: var(--transition);
}

.footer-social a:hover {
  background: var(--gradient-main);
  border-color: transparent;
  transform: translateY(-2px);
}

/* === Scroll Animations === */
.fade-in {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

.fade-in-left {
  opacity: 0;
  transform: translateX(-30px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.fade-in-left.visible {
  opacity: 1;
  transform: translateX(0);
}

.fade-in-right {
  opacity: 0;
  transform: translateX(30px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.fade-in-right.visible {
  opacity: 1;
  transform: translateX(0);
}

/* === Breadcrumb === */
.breadcrumb {
  padding: 120px 0 20px;
  font-size: 0.9rem;
}

.breadcrumb a {
  color: var(--text-muted);
}

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

.breadcrumb span {
  color: var(--text-muted);
  margin: 0 8px;
}

/* === Page Header === */
.page-header {
  text-align: center;
  padding: 40px 0 80px;
}

.page-header h1 {
  background: var(--gradient-main);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: 16px;
}

/* === Content Pages (Privacy, Terms) === */
.content-page {
  max-width: 800px;
  margin: 0 auto;
}

.content-page h2 {
  font-size: 1.5rem;
  margin: 40px 0 16px;
  color: var(--primary-light);
}

.content-page h3 {
  font-size: 1.2rem;
  margin: 24px 0 12px;
}

.content-page p,
.content-page li {
  color: var(--text-secondary);
  line-height: 1.9;
  margin-bottom: 12px;
}

.content-page ul {
  padding-left: 24px;
  margin-bottom: 16px;
}

.content-page ul li {
  list-style: disc;
}

/* === Responsive === */
@media (max-width: 1024px) {
  .hero-content {
    grid-template-columns: 1fr;
    text-align: center;
  }
  
  .hero-text p {
    margin: 0 auto 40px;
  }
  
  .hero-buttons {
    justify-content: center;
  }
  
  .hero-stats {
    justify-content: center;
  }
  
  .hero-visual {
    order: -1;
  }
  
  .about-content {
    grid-template-columns: 1fr;
  }
  
  .footer-grid {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 768px) {
  .nav-links {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: rgba(10, 10, 26, 0.98);
    backdrop-filter: blur(20px);
    flex-direction: column;
    padding: 24px;
    gap: 16px;
    border-bottom: 1px solid var(--border-glass);
  }
  
  .nav-links.active {
    display: flex;
  }
  
  .nav-toggle {
    display: flex;
  }
  
  .nav-cta {
    display: none;
  }
  
  .section {
    padding: 60px 0;
  }
  
  .features-grid {
    grid-template-columns: 1fr;
  }
  
  .footer-grid {
    grid-template-columns: 1fr;
  }
  
  .footer-bottom {
    flex-direction: column;
    text-align: center;
  }
  
  .hero-stats {
    flex-direction: column;
    gap: 20px;
  }
  
  .phone-mockup {
    width: 220px;
    height: 440px;
  }
}

@media (max-width: 480px) {
  .hero-buttons {
    flex-direction: column;
    align-items: center;
  }
  
  .btn {
    width: 100%;
    justify-content: center;
  }
  
  .download-options {
    grid-template-columns: 1fr;
  }
}

/* === Floating Particles === */
.particles {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  z-index: -1;
  overflow: hidden;
}

.particle {
  position: absolute;
  width: 4px;
  height: 4px;
  background: var(--primary);
  border-radius: 50%;
  opacity: 0.3;
  animation: particleFloat linear infinite;
}

@keyframes particleFloat {
  0% { transform: translateY(100vh) rotate(0deg); opacity: 0; }
  10% { opacity: 0.3; }
  90% { opacity: 0.3; }
  100% { transform: translateY(-100px) rotate(720deg); opacity: 0; }
}

/* === Badge === */
.badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 14px;
  background: var(--bg-glass);
  border: 1px solid var(--border-glass);
  border-radius: 50px;
  font-size: 0.85rem;
  color: var(--text-secondary);
  margin-bottom: 24px;
}

.badge .dot {
  width: 6px;
  height: 6px;
  background: #22c55e;
  border-radius: 50%;
  animation: pulse 2s ease-in-out infinite;
}

@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.4; }
}

/* === Scrollbar === */
::-webkit-scrollbar {
  width: 8px;
}

::-webkit-scrollbar-track {
  background: var(--bg-dark);
}

::-webkit-scrollbar-thumb {
  background: rgba(255, 107, 53, 0.3);
  border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
  background: rgba(255, 107, 53, 0.5);
}