/* Modern Academy Theme - Orange & Purple Design System */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800&family=Playfair+Display:wght@400;500;600;700&display=swap');

:root {
  /* Academy Color Palette */
  --primary-orange: #FF6B35;
  --primary-purple: #6B46C1;
  --secondary-orange: #FF8C42;
  --secondary-purple: #8B5CF6;
  --accent-gold: #F59E0B;
  --accent-silver: #6B7280;
  
  /* Gradients */
  --gradient-primary: linear-gradient(135deg, var(--primary-orange) 0%, var(--primary-purple) 100%);
  --gradient-secondary: linear-gradient(135deg, var(--secondary-orange) 0%, var(--secondary-purple) 100%);
  --gradient-accent: linear-gradient(135deg, var(--accent-gold) 0%, var(--primary-orange) 100%);
  
  /* Neutral Colors */
  --bg-primary: #FAFAFA;
  --bg-secondary: #FFFFFF;
  --text-primary: #1F2937;
  --text-secondary: #6B7280;
  --text-muted: #9CA3AF;
  --border-light: #E5E7EB;
  --border-medium: #D1D5DB;
  
  /* 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);
  
  /* Typography */
  --font-primary: 'Inter', system-ui, -apple-system, sans-serif;
  --font-display: 'Playfair Display', Georgia, serif;
  
  /* Spacing */
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;
  
  /* Border Radius */
  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-primary);
  font-weight: 400;
  line-height: 1.6;
  color: var(--text-primary);
  background: var(--bg-primary);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* Container */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--space-lg);
}

/* Header */
.site-header {
  background: var(--bg-secondary);
  border-bottom: 1px solid var(--border-light);
  box-shadow: var(--shadow-sm);
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(10px);
}

.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-md) var(--space-lg);
}

.site-header h1 {
  font-family: var(--font-display);
  font-size: 1.5rem;
  font-weight: 600;
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin: 0;
}

.site-header nav {
  display: flex;
  gap: var(--space-lg);
}

.site-header nav a {
  text-decoration: none;
  color: var(--text-secondary);
  font-weight: 500;
  padding: var(--space-sm) var(--space-md);
  border-radius: var(--radius-md);
  transition: all 0.3s ease;
  position: relative;
}

.site-header nav a:hover {
  color: var(--primary-orange);
  background: rgba(255, 107, 53, 0.1);
  transform: translateY(-1px);
}

.site-header nav a.active {
  color: var(--primary-orange);
  background: var(--gradient-primary);
  color: white;
}

/* Hero Section */
.hero {
  background: var(--gradient-primary);
  color: white;
  padding: var(--space-2xl);
  margin: var(--space-xl) 0;
  border-radius: var(--radius-xl);
  text-align: center;
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><defs><pattern id="grain" width="100" height="100" patternUnits="userSpaceOnUse"><circle cx="50" cy="50" r="1" fill="white" opacity="0.1"/></pattern></defs><rect width="100" height="100" fill="url(%23grain)"/></svg>');
  opacity: 0.1;
}

.hero h2 {
  font-family: var(--font-display);
  font-size: 2.5rem;
  font-weight: 600;
  margin-bottom: var(--space-md);
  position: relative;
  z-index: 1;
}

.hero p {
  font-size: 1.125rem;
  margin-bottom: var(--space-md);
  opacity: 0.9;
  position: relative;
  z-index: 1;
}

.hero .meta {
  font-size: 0.875rem;
  opacity: 0.8;
  position: relative;
  z-index: 1;
}

/* Articles Section */
.articles {
  margin: var(--space-2xl) 0;
}

.articles h3 {
  font-family: var(--font-display);
  font-size: 1.875rem;
  font-weight: 600;
  margin-bottom: var(--space-xl);
  color: var(--text-primary);
  position: relative;
}

.articles h3::after {
  content: '';
  position: absolute;
  bottom: -8px;
  left: 0;
  width: 60px;
  height: 3px;
  background: var(--gradient-primary);
  border-radius: 2px;
}

.articles-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
  gap: var(--space-lg);
}

/* Cards */
.card {
  background: var(--bg-secondary);
  padding: var(--space-xl);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
  border: 1px solid var(--border-light);
  transition: all 0.3s ease;
  position: relative;
  overflow: hidden;
}

.card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  background: var(--gradient-primary);
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-xl);
  border-color: var(--primary-orange);
}

.card h4 {
  font-family: var(--font-display);
  font-size: 1.25rem;
  font-weight: 600;
  margin-bottom: var(--space-sm);
  color: var(--text-primary);
  line-height: 1.4;
}

.card .authors {
  color: var(--primary-orange);
  font-weight: 500;
  font-size: 0.875rem;
  margin-bottom: var(--space-md);
}

.card .abstract {
  color: var(--text-secondary);
  margin-bottom: var(--space-lg);
  line-height: 1.6;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-md) var(--space-lg);
  background: var(--gradient-primary);
  color: white;
  text-decoration: none;
  border-radius: var(--radius-md);
  font-weight: 500;
  transition: all 0.3s ease;
  border: none;
  cursor: pointer;
  position: relative;
  overflow: hidden;
}

.btn::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
  transition: left 0.5s;
}

.btn:hover::before {
  left: 100%;
}

.btn:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

.btn:active {
  transform: translateY(0);
}

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

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

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

/* Tables */
.table {
  width: 100%;
  border-collapse: collapse;
  background: var(--bg-secondary);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-md);
  border: 1px solid var(--border-light);
}

.table th {
  background: var(--gradient-primary);
  color: white;
  padding: var(--space-lg);
  text-align: left;
  font-weight: 600;
  font-size: 0.875rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.table td {
  padding: var(--space-lg);
  border-bottom: 1px solid var(--border-light);
  color: var(--text-primary);
}

.table tr:hover {
  background: rgba(255, 107, 53, 0.05);
}

.table tr:last-child td {
  border-bottom: none;
}

/* Forms */
label {
  display: block;
  margin-bottom: var(--space-sm);
  font-weight: 500;
  color: var(--text-primary);
}

input[type="text"],
input[type="email"],
input[type="password"],
textarea,
input[type="file"],
select {
  width: 100%;
  padding: var(--space-md);
  border: 2px solid var(--border-medium);
  border-radius: var(--radius-md);
  font-family: var(--font-primary);
  font-size: 1rem;
  transition: all 0.3s ease;
  background: var(--bg-secondary);
}

input[type="text"]:focus,
input[type="email"]:focus,
input[type="password"]:focus,
textarea:focus,
select:focus {
  outline: none;
  border-color: var(--primary-orange);
  box-shadow: 0 0 0 3px rgba(255, 107, 53, 0.1);
}

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

/* Notes and Alerts */
.note {
  background: linear-gradient(135deg, #E0F2FE 0%, #F0F9FF 100%);
  border: 1px solid #0EA5E9;
  color: #0C4A6E;
  padding: var(--space-lg);
  margin-top: var(--space-lg);
  border-radius: var(--radius-md);
  border-left: 4px solid #0EA5E9;
}

.note.success {
  background: linear-gradient(135deg, #DCFCE7 0%, #F0FDF4 100%);
  border-color: #22C55E;
  color: #166534;
  border-left-color: #22C55E;
}

.note.warning {
  background: linear-gradient(135deg, #FEF3C7 0%, #FFFBEB 100%);
  border-color: #F59E0B;
  color: #92400E;
  border-left-color: #F59E0B;
}

/* Footer */
.site-footer {
  margin-top: var(--space-2xl);
  padding: var(--space-xl) 0;
  text-align: center;
  color: var(--text-muted);
  background: var(--bg-secondary);
  border-top: 1px solid var(--border-light);
}

/* Utility Classes */
.hidden {
  display: none;
}

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

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

/* Responsive Design */
@media (max-width: 768px) {
  .container {
    padding: 0 var(--space-md);
  }
  
  .site-header .container {
    flex-direction: column;
    gap: var(--space-md);
    padding: var(--space-md);
  }
  
  .site-header nav {
    flex-wrap: wrap;
    justify-content: center;
    gap: var(--space-md);
  }
  
  .hero {
    padding: var(--space-xl);
    margin: var(--space-lg) 0;
  }
  
  .hero h2 {
    font-size: 2rem;
  }
  
  .articles-grid {
    grid-template-columns: 1fr;
    gap: var(--space-md);
  }
  
  .card {
    padding: var(--space-lg);
  }
  
  .table {
    font-size: 0.875rem;
  }
  
  .table th,
  .table td {
    padding: var(--space-md);
  }
}

@media (max-width: 480px) {
  .hero h2 {
    font-size: 1.75rem;
  }
  
  .card {
    padding: var(--space-md);
  }
  
  .btn {
    width: 100%;
    justify-content: center;
  }
}

/* Animations */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.card {
  animation: fadeInUp 0.6s ease-out;
}

.card:nth-child(2) {
  animation-delay: 0.1s;
}

.card:nth-child(3) {
  animation-delay: 0.2s;
}

/* Loading States */
.loading {
  position: relative;
  overflow: hidden;
}

.loading::after {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.4), transparent);
  animation: loading 1.5s infinite;
}

@keyframes loading {
  0% {
    left: -100%;
  }
  100% {
    left: 100%;
  }
}