/* Glassmorphism Design System for Renxuai.com */
:root {
  /* Primary brand colors */
  --primary-500: #2563eb;
  --primary-600: #1d4ed8;
  --primary-700: #1e40af;
  --cta-500: #f97316;
  --cta-600: #ea580c;
  
  /* Glassmorphism base colors */
  --glass-bg: rgba(255, 255, 255, 0.8);
  --glass-bg-dark: rgba(255, 255, 255, 0.1);
  --glass-border: rgba(255, 255, 255, 0.2);
  --glass-border-dark: rgba(255, 255, 255, 0.1);
  
  /* Text colors */
  --text-primary: #1e293b;
  --text-secondary: #475569;
  --text-muted: #64748b;
  --text-on-primary: #ffffff;
  
  /* Background colors */
  --bg-base: #f8fafc;
  --bg-surface: #ffffff;
  
  /* Dark mode variants */
  --dark-bg-base: #0f172a;
  --dark-bg-surface: #1e293b;
  --dark-text-primary: #f1f5f9;
  --dark-text-secondary: #cbd5e1;
  --dark-text-muted: #94a3b8;
  
  /* 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 -2px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -4px rgba(0, 0, 0, 0.1);
  
  /* Border radius */
  --radius-sm: 0.25rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
  --radius-2xl: 1.5rem;
  --radius-full: 9999px;
  
  /* Spacing */
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2rem;
  --spacing-2xl: 3rem;
  
  /* Fonts */
  --font-sans: "Poppins", "Open Sans", "Inter", ui-sans-serif, system-ui, sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace;
}

/* Dark mode variables */
[data-theme="dark"] {
  --glass-bg: rgba(30, 41, 59, 0.8);
  --glass-bg-dark: rgba(15, 23, 42, 0.8);
  --glass-border: rgba(255, 255, 255, 0.1);
  --glass-border-dark: rgba(255, 255, 255, 0.05);
  --text-primary: var(--dark-text-primary);
  --text-secondary: var(--dark-text-secondary);
  --text-muted: var(--dark-text-muted);
  --bg-base: var(--dark-bg-base);
  --bg-surface: var(--dark-bg-surface);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font-sans);
  background: linear-gradient(135deg, var(--bg-base) 0%, #e2e8f0 100%);
  color: var(--text-primary);
  line-height: 1.6;
}

/* Container */
.container {
  width: min(1200px, 92vw);
  margin: 0 auto;
}

/* Skip link for accessibility */
.skip-link {
  position: absolute;
  left: -9999px;
}

.skip-link:focus {
  left: 12px;
  top: 10px;
  background: var(--primary-500);
  color: var(--text-on-primary);
  padding: 6px 10px;
  border-radius: var(--radius-md);
  z-index: 1000;
}

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  background: var(--glass-bg);
  border-bottom: 1px solid var(--glass-border);
}

.header-inner,
.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 0;
  gap: 12px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 20px;
  font-weight: 700;
  letter-spacing: 0.02em;
  color: var(--text-primary);
}

.brand-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--primary-500);
  box-shadow: 0 0 0 4px rgba(37, 99, 235, 0.2);
}

.nav,
.header-nav {
  display: flex;
  gap: 20px;
  font-size: 14px;
  font-weight: 500;
}

.nav a,
.header-nav a {
  color: var(--text-secondary);
  text-decoration: none;
  transition: color 0.2s ease;
}

.nav a:hover,
.header-nav a:hover {
  color: var(--primary-500);
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 12px;
}

.theme-toggle {
  border: 1px solid var(--glass-border);
  background: var(--glass-bg);
  color: var(--text-primary);
  border-radius: var(--radius-full);
  padding: 8px 12px;
  cursor: pointer;
  font-size: 14px;
  font-weight: 500;
  transition: all 0.2s ease;
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
}

.theme-toggle:hover {
  background: var(--primary-500);
  color: var(--text-on-primary);
  border-color: var(--primary-500);
}

.back {
  text-decoration: none;
  background: var(--primary-500);
  color: var(--text-on-primary);
  padding: 8px 16px;
  border-radius: var(--radius-full);
  font-weight: 600;
  font-size: 14px;
  transition: all 0.2s ease;
}

.back:hover {
  background: var(--primary-600);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

/* Hero section */
.hero {
  padding: 64px 0 40px;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.5fr 0.9fr;
  gap: 32px;
  align-items: stretch;
}

.eyebrow,
.section-kicker {
  text-transform: uppercase;
  letter-spacing: 0.1em;
  font-size: 12px;
  font-weight: 600;
  color: var(--primary-500);
  margin-bottom: 12px;
}

.hero h1,
.section-head h2 {
  margin: 0;
  font-size: clamp(32px, 4vw, 56px);
  font-weight: 700;
  line-height: 1.1;
  letter-spacing: -0.02em;
}

.hero-text,
.desc,
.section-desc {
  margin: 16px 0 0;
  max-width: 760px;
  font-size: 18px;
  line-height: 1.7;
  color: var(--text-secondary);
}

.hero-actions {
  display: flex;
  gap: 16px;
  margin-top: 32px;
  flex-wrap: wrap;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 24px;
  border-radius: var(--radius-full);
  border: 2px solid transparent;
  font-size: 15px;
  font-weight: 600;
  text-decoration: none;
  cursor: pointer;
  transition: all 0.2s ease;
  font-family: var(--font-sans);
}

.btn-primary {
  background: var(--primary-500);
  color: var(--text-on-primary);
  border-color: var(--primary-500);
}

.btn-primary:hover {
  background: var(--primary-600);
  border-color: var(--primary-600);
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

.btn-secondary {
  background: transparent;
  color: var(--text-primary);
  border-color: var(--glass-border);
}

.btn-secondary:hover {
  background: var(--glass-bg);
  border-color: var(--primary-500);
  color: var(--primary-500);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.btn-cta {
  background: var(--cta-500);
  color: var(--text-on-primary);
  border-color: var(--cta-500);
}

.btn-cta:hover {
  background: var(--cta-600);
  border-color: var(--cta-600);
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

/* Glassmorphism cards */
.glass-card {
  background: var(--glass-bg);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-xl);
  padding: 24px;
  box-shadow: var(--shadow-md);
  transition: all 0.3s ease;
}

.glass-card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
  border-color: rgba(37, 99, 235, 0.3);
}

[data-theme="dark"] .glass-card {
  background: var(--glass-bg-dark);
  border: 1px solid var(--glass-border-dark);
}

/* Metric cards */
.metric-card {
  background: var(--glass-bg);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-xl);
  padding: 24px;
  box-shadow: var(--shadow-md);
}

.metric-card strong {
  display: block;
  font-size: 36px;
  font-weight: 700;
  margin-top: 8px;
  color: var(--primary-500);
}

.metric-label {
  display: inline-block;
  font-size: 12px;
  font-weight: 600;
  color: var(--text-muted);
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.metric-card.large p {
  color: var(--text-secondary);
  margin: 12px 0 0;
  line-height: 1.7;
}

/* Sections */
.section {
  padding: 40px 0 60px;
}

.section-alt {
  background: rgba(248, 250, 252, 0.5);
  border-top: 1px solid var(--glass-border);
  border-bottom: 1px solid var(--glass-border);
}

.section-head {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 20px;
  margin-bottom: 24px;
}

/* Grid layouts */
.intro-grid,
.method-grid,
.directory-grid,
.card-grid,
.vendor-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 24px;
}

@media (min-width: 768px) {
  .intro-grid,
  .method-grid {
    grid-template-columns: repeat(3, 1fr);
  }
  
  .directory-grid,
  .card-grid,
  .vendor-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

.intro-card,
.method-card {
  background: var(--glass-bg);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-xl);
  padding: 28px;
  box-shadow: var(--shadow-md);
}

.intro-card h2,
.method-card h3 {
  margin: 0 0 16px;
  font-size: 20px;
  font-weight: 700;
}

/* Filters */
.filters {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
  margin-bottom: 20px;
}

.filters label {
  display: flex;
  flex-direction: column;
  gap: 8px;
  font-size: 13px;
  font-weight: 500;
  color: var(--text-muted);
}

.filters select,
.filters input {
  min-width: 180px;
  padding: 12px 16px;
  border-radius: var(--radius-lg);
  border: 1px solid var(--glass-border);
  background: var(--glass-bg);
  font-size: 15px;
  color: var(--text-primary);
  font-family: var(--font-sans);
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
}

.filters input {
  width: min(100%, 460px);
}

.result-meta {
  font-size: 14px;
  color: var(--text-muted);
  margin-bottom: 24px;
}

/* Badges */
.badge {
  display: inline-flex;
  align-items: center;
  padding: 6px 14px;
  border-radius: var(--radius-full);
  font-size: 12px;
  font-weight: 600;
  background: rgba(37, 99, 235, 0.1);
  color: var(--primary-500);
  border: 1px solid rgba(37, 99, 235, 0.2);
}

/* Pills */
.pill {
  display: inline-flex;
  align-items: center;
  padding: 8px 16px;
  border-radius: var(--radius-full);
  background: var(--glass-bg);
  border: 1px solid var(--glass-border);
  font-size: 13px;
  color: var(--text-primary);
  font-weight: 500;
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
  transition: all 0.2s ease;
}

.pill-button {
  cursor: pointer;
}

.pill-button:hover {
  background: var(--primary-500);
  color: var(--text-on-primary);
  border-color: var(--primary-500);
  transform: translateY(-1px);
}

/* Lists */
.bullet-list {
  margin: 0;
  padding-left: 24px;
  color: var(--text-secondary);
  line-height: 1.7;
}

.bullet-list li {
  margin: 8px 0;
}

/* Footer */
.site-footer {
  padding: 48px 0 64px;
}

.footer-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  border-top: 1px solid var(--glass-border);
  padding-top: 32px;
}

.footer-row p {
  color: var(--text-muted);
  margin: 8px 0 0;
}

.footer-links {
  display: flex;
  gap: 24px;
}

.footer-links a {
  color: var(--text-secondary);
  font-weight: 500;
  transition: color 0.2s ease;
}

.footer-links a:hover {
  color: var(--primary-500);
}

/* AINEWS specific styles */
.content-tabs {
  display: flex;
  gap: 12px;
  margin-bottom: 28px;
  flex-wrap: wrap;
  padding: 0 20px;
}

.content-tab {
  padding: 10px 20px;
  background: var(--glass-bg);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-full);
  cursor: pointer;
  font-size: 14px;
  font-weight: 600;
  color: var(--text-secondary);
  transition: all 0.2s ease;
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
}

.content-tab:hover {
  background: var(--primary-500);
  color: var(--text-on-primary);
  border-color: var(--primary-500);
}

.content-tab.active {
  background: var(--primary-500);
  color: var(--text-on-primary);
  border-color: var(--primary-500);
}

.top-brief {
  margin: 0;
  background: var(--glass-bg);
  border: 1px solid var(--glass-border);
  border-left: 4px solid var(--primary-500);
  border-radius: var(--radius-lg);
  padding: 16px 20px;
  color: var(--text-primary);
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
}

.fold {
  background: var(--glass-bg);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-lg);
  padding: 12px 16px;
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
}

.fold > summary {
  cursor: pointer;
  font-size: 16px;
  font-weight: 600;
  color: var(--text-primary);
  list-style: none;
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 8px 0;
}

.fold > summary::-webkit-details-marker {
  display: none;
}

.fold > summary::before {
  content: '▸';
  color: var(--primary-500);
  transition: transform 0.2s ease;
}

.fold[open] > summary::before {
  transform: rotate(90deg);
}

.paper-card,
.news-item,
.item,
.month-card,
.hot-card {
  background: var(--glass-bg);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-lg);
  padding: 16px;
  transition: all 0.2s ease;
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
}

.paper-card:hover,
.news-item:hover,
.item:hover,
.month-card:hover,
.hot-card:hover {
  transform: translateY(-2px);
  border-color: rgba(37, 99, 235, 0.3);
  box-shadow: var(--shadow-md);
}

/* Responsive design */
@media (max-width: 960px) {
  .hero-grid,
  .intro-grid,
  .method-grid,
  .directory-grid,
  .card-grid,
  .vendor-grid,
  .footer-row {
    grid-template-columns: 1fr;
  }
  
  .section-head,
  .header-inner,
  .topbar {
    display: block;
  }
  
  .nav,
  .header-nav {
    margin-top: 12px;
    flex-wrap: wrap;
    gap: 12px;
  }
  
  .content-tabs {
    padding: 0;
  }
}

@media (max-width: 640px) {
  .hero {
    padding: 40px 0 24px;
  }
  
  .hero-grid {
    gap: 20px;
  }
  
  .hero-panel {
    grid-template-columns: 1fr;
  }
  
  .hero-actions {
    gap: 12px;
    margin-top: 24px;
  }
  
  .btn {
    width: 100%;
  }
  
  .filters {
    flex-direction: column;
    gap: 12px;
  }
  
  .filters input,
  .filters select {
    width: 100%;
    min-width: 0;
  }
  
  .section {
    padding: 28px 0 40px;
  }
  
  .intro-card,
  .method-card,
  .metric-card,
  .glass-card {
    padding: 20px;
    border-radius: var(--radius-lg);
  }
}

/* Accessibility enhancements */
:focus-visible {
  outline: 2px solid var(--primary-500);
  outline-offset: 2px;
}

/* Ensure sufficient contrast for WCAG AA compliance */
a:not(.btn):not(.back):not(.link-arrow) {
  color: var(--primary-500);
  text-decoration: underline;
  text-underline-offset: 2px;
}

a:not(.btn):not(.back):not(.link-arrow):hover {
  color: var(--primary-600);
}

/* Loading states */
.loading {
  opacity: 0.7;
  pointer-events: none;
}

/* Empty states */
.empty-state {
  text-align: center;
  padding: 48px 24px;
  background: var(--glass-bg);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-xl);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
}

.empty-state h3 {
  margin: 0 0 12px;
  font-size: 24px;
  font-weight: 700;
}

.empty-state p {
  margin: 0;
  color: var(--text-muted);
  line-height: 1.7;
}