/* ==========================================================================
   Base Design System - Lunar Minimalism ("纯白月相")
   ========================================================================== */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600&family=Playfair+Display:ital,wght@0,400;0,600;1,400&display=swap');

:root {
  --bg-primary: #FAFAFA;
  --bg-glow: #E8E4F0;
  --text-primary: #1A1A2E;
  --text-secondary: rgba(26, 26, 46, 0.7);
  --accent: #6C63FF;
  --accent-hover: #564ED4;
  --card-bg: rgba(255, 255, 255, 0.6);
  --card-border: rgba(108, 99, 255, 0.1);
  --glass-blur: blur(20px);
  --font-sans: 'Inter', system-ui, -apple-system, sans-serif;
  --font-serif: 'Playfair Display', Georgia, serif;
  --transition: all 0.4s cubic-bezier(0.25, 0.46, 0.45, 0.94);
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

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

body {
  font-family: var(--font-sans);
  color: var(--text-primary);
  background-color: var(--bg-primary);
  background-image: radial-gradient(circle at top center, var(--bg-glow) 0%, var(--bg-primary) 50%);
  background-attachment: fixed;
  background-repeat: no-repeat;
  background-size: 100vw 100vh;
  line-height: 1.6;
  overflow-x: hidden;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-serif);
  font-weight: 600;
  line-height: 1.2;
  margin-bottom: 1rem;
}

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

a:hover {
  color: var(--accent-hover);
}

ul {
  list-style: none;
}

/* ==========================================================================
   Typography & Utilities
   ========================================================================== */

.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 2rem;
}

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

.glass-panel {
  background: var(--card-bg);
  backdrop-filter: var(--glass-blur);
  -webkit-backdrop-filter: var(--glass-blur);
  border: 1px solid var(--card-border);
  border-radius: 16px;
}

/* ==========================================================================
   Buttons
   ========================================================================== */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.8rem 2rem;
  border-radius: 30px;
  font-weight: 500;
  font-size: 1rem;
  cursor: pointer;
  transition: var(--transition);
  border: 1px solid transparent;
}

.btn-primary {
  background-color: var(--accent);
  color: white;
  box-shadow: 0 4px 15px rgba(108, 99, 255, 0.3);
}

.btn-primary:hover {
  background-color: var(--accent-hover);
  color: white;
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(108, 99, 255, 0.4);
}

.btn-secondary {
  background-color: transparent;
  color: var(--text-primary);
  border-color: var(--card-border);
  backdrop-filter: var(--glass-blur);
  -webkit-backdrop-filter: var(--glass-blur);
}

.btn-secondary:hover {
  background-color: rgba(108, 99, 255, 0.05);
  border-color: rgba(108, 99, 255, 0.3);
  transform: translateY(-2px);
}

/* ==========================================================================
   Layout Sections
   ========================================================================== */

section {
  padding: 6rem 0;
}

/* Hero Section */
.hero {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  position: relative;
  padding-top: 2rem;
}

.hero-moon {
  margin-bottom: 2rem;
  animation: slow-rotate 60s linear infinite;
  opacity: 0.8;
}

.hero-title {
  font-size: 4rem;
  letter-spacing: -0.02em;
  margin-bottom: 0.5rem;
  font-style: italic;
}

.hero-subtitle {
  font-family: var(--font-sans);
  font-size: 1.25rem;
  color: var(--text-secondary);
  font-weight: 300;
  letter-spacing: 0.05em;
  margin-bottom: 3rem;
  text-transform: uppercase;
}

.hero-cta {
  display: flex;
  gap: 1.5rem;
  flex-wrap: wrap;
  justify-content: center;
}

/* Features Cards */
.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2rem;
  margin-top: 4rem;
}

.feature-card {
  padding: 3rem 2rem;
  text-align: center;
  transition: var(--transition);
}

.feature-card:hover {
  transform: translateY(-5px);
  border-color: rgba(108, 99, 255, 0.3);
}

.feature-icon {
  width: 64px;
  height: 64px;
  margin: 0 auto 1.5rem;
  color: var(--accent);
}

.feature-title {
  font-size: 1.5rem;
  margin-bottom: 1rem;
}

.feature-desc {
  color: var(--text-secondary);
  font-weight: 300;
}

/* Media & AI */
.media-ai {
  text-align: center;
}

.logo-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
  gap: 2rem;
  margin-top: 3rem;
  align-items: center;
  justify-items: center;
  opacity: 0.7;
}

.logo-grid img {
  max-width: 100px;
  filter: grayscale(100%) opacity(0.6);
  transition: var(--transition);
}

.logo-grid img:hover {
  filter: grayscale(0%) opacity(1);
}

/* Pricing */
.pricing-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 2rem;
  margin-top: 4rem;
}

.pricing-card {
  padding: 3rem 2rem;
  display: flex;
  flex-direction: column;
  position: relative;
  overflow: hidden;
}

.pricing-card.popular::before {
  content: 'RECOMMENDED';
  position: absolute;
  top: 1.5rem;
  right: -2rem;
  background: var(--accent);
  color: white;
  font-size: 0.75rem;
  font-weight: 600;
  padding: 0.25rem 3rem;
  transform: rotate(45deg);
  letter-spacing: 0.1em;
}

.price {
  font-size: 3rem;
  font-family: var(--font-serif);
  margin: 1.5rem 0;
  color: var(--accent);
}

.price span {
  font-size: 1rem;
  font-family: var(--font-sans);
  color: var(--text-secondary);
}

.pricing-features {
  margin: 2rem 0;
  flex-grow: 1;
  text-align: left;
}

.pricing-features li {
  margin-bottom: 1rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-weight: 300;
}

.pricing-features li::before {
  content: '✓';
  color: var(--accent);
}

/* FAQ */
.faq-grid {
  max-width: 800px;
  margin: 3rem auto 0;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.faq-item {
  padding: 1.5rem;
  text-align: left;
}

.faq-question {
  font-family: var(--font-serif);
  font-size: 1.25rem;
  margin-bottom: 0.5rem;
  color: var(--accent);
}

.faq-answer {
  color: var(--text-secondary);
  font-weight: 300;
}

/* Reviews */
.reviews-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 2rem;
  margin-top: 4rem;
}

.review-card {
  padding: 2rem;
  text-align: left;
}

.review-text {
  font-style: italic;
  font-weight: 300;
  margin-bottom: 1.5rem;
}

.review-author {
  font-weight: 500;
  font-size: 0.9rem;
  color: var(--accent);
}

/* Footer */
footer {
  border-top: 1px solid var(--card-border);
  padding: 4rem 0 2rem;
  margin-top: 4rem;
}

.footer-content {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 4rem;
  margin-bottom: 3rem;
}

.footer-brand h3 {
  font-size: 2rem;
  margin-bottom: 1rem;
  color: var(--text-primary);
}

.footer-brand p {
  color: var(--text-secondary);
  font-weight: 300;
  max-width: 300px;
}

.footer-links {
  display: flex;
  gap: 4rem;
}

.footer-links-col {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.footer-links-col h4 {
  font-family: var(--font-sans);
  font-size: 0.9rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 0.5rem;
}

.footer-links-col a {
  color: var(--text-secondary);
  font-weight: 300;
  font-size: 0.9rem;
}

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

.footer-bottom {
  text-align: center;
  color: var(--text-secondary);
  font-size: 0.8rem;
  font-weight: 300;
}

/* Auxiliary Pages Content Layout */
.page-header {
  padding: 8rem 0 4rem;
  text-align: center;
}

.page-content {
  max-width: 800px;
  margin: 0 auto;
  padding: 2rem;
  margin-bottom: 6rem;
}

.page-content h2 {
  margin-top: 2.5rem;
  color: var(--accent);
}

.page-content p, .page-content ul {
  margin-bottom: 1.5rem;
  font-weight: 300;
}

.page-content ul {
  padding-left: 1.5rem;
  list-style: disc;
}

/* ==========================================================================
   Animations & Motion
   ========================================================================== */

@keyframes slow-rotate {
  from { transform: rotate(0deg); }
  to { transform: rotate(360deg); }
}

.fade-in {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 1s ease-out, transform 1s ease-out;
}

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

/* Moon phases progress indicator */
.moon-phases {
  position: fixed;
  right: 2rem;
  top: 50%;
  transform: translateY(-50%);
  display: flex;
  flex-direction: column;
  gap: 1rem;
  z-index: 100;
}

.moon-phase-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  border: 1px solid var(--accent);
  background: transparent;
  transition: var(--transition);
}

.moon-phase-dot.active {
  background: var(--accent);
  box-shadow: 0 0 10px var(--accent);
}

/* ==========================================================================
   Navigation Bar
   ========================================================================== */

.navbar {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  padding: 1rem 0;
  background: rgba(250, 250, 250, 0.8);
  backdrop-filter: var(--glass-blur);
  -webkit-backdrop-filter: var(--glass-blur);
  border-bottom: 1px solid var(--card-border);
  z-index: 1000;
  transition: var(--transition);
}

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

.nav-logo {
  font-family: var(--font-serif);
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.nav-links {
  display: flex;
  gap: 2rem;
  align-items: center;
}

.nav-links a:not(.btn) {
  color: var(--text-secondary);
  font-weight: 500;
  font-size: 0.95rem;
}

.nav-links a:not(.btn):hover, .nav-links a:not(.btn).active {
  color: var(--accent);
}

.nav-links a.btn-primary {
  color: white;
}

/* Add padding to body to account for fixed navbar */
body {
  padding-top: 80px;
}

/* ==========================================================================
   Knowledge Base & Articles
   ========================================================================== */

.article-list {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 2rem;
  margin-top: 3rem;
}

.article-card {
  padding: 2rem;
  display: flex;
  flex-direction: column;
}

.article-card h3 {
  font-size: 1.25rem;
  margin-bottom: 1rem;
}

.article-card p {
  color: var(--text-secondary);
  font-size: 0.95rem;
  margin-bottom: 1.5rem;
  flex-grow: 1;
}

.article-card .read-more {
  font-weight: 500;
  color: var(--accent);
  display: inline-flex;
  align-items: center;
}

.article-card:hover {
  transform: translateY(-5px);
  border-color: rgba(108, 99, 255, 0.3);
}

.article-content {
  max-width: 800px;
  margin: 0 auto;
  padding: 3rem;
  font-size: 1.1rem;
}

.article-content h1 {
  font-size: 2.5rem;
  text-align: center;
  margin-bottom: 2rem;
  color: var(--accent);
}

.article-content h2 {
  font-size: 1.8rem;
  margin-top: 3rem;
  margin-bottom: 1.5rem;
}

.article-content p {
  margin-bottom: 1.5rem;
  line-height: 1.8;
  font-weight: 300;
}

.article-content a {
  text-decoration: underline;
  text-underline-offset: 4px;
}

.article-content strong {
  font-weight: 500;
  color: var(--text-primary);
}

.article-meta {
  text-align: center;
  color: var(--text-secondary);
  font-size: 0.9rem;
  margin-bottom: 3rem;
  padding-bottom: 2rem;
  border-bottom: 1px solid var(--card-border);
}

/* ==========================================================================
   Media Queries (Responsive)
   ========================================================================== */

@media (max-width: 768px) {
  .hero-title {
    font-size: 3rem;
  }
  
  .features-grid {
    grid-template-columns: 1fr;
  }

  .pricing-grid {
    grid-template-columns: 1fr;
  }
  
  .footer-content {
    grid-template-columns: 1fr;
    gap: 2rem;
  }
  
  .footer-links {
    flex-direction: column;
    gap: 2rem;
  }

  .btn {
    width: 100%;
    padding: 1rem;
  }
  
  .hero-cta {
    width: 100%;
    flex-direction: column;
  }
  
  .moon-phases {
    display: none; /* Hide on mobile to save space */
  }
}