/* Clean, Polished Design System */

/* Variables */
:root {
  --color-white: #ffffff;
  --color-gray-50: #f8fafc;
  --color-gray-100: #f1f5f9;
  --color-gray-200: #e2e8f0;
  --color-gray-300: #cbd5e1;
  --color-gray-500: #64748b;
  --color-gray-600: #475569;
  --color-gray-700: #334155;
  --color-gray-800: #1e293b;
  --color-gray-900: #0f172a;
  
  --color-primary: #3b82f6;
  --color-accent: #06b6d4;
  --color-success: #10b981;
  --color-warning: #f59e0b;
  
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 8px 25px rgba(0, 0, 0, 0.15);
}

/* Global */
body {
  font-family: -apple-system, BlinkMacSystemFont, 'Inter', 'Segoe UI', Roboto, sans-serif;
  line-height: 1.6;
  color: var(--color-gray-700);
  background: var(--color-gray-50);
  margin: 0;
}

h1, h2, h3, h4, h5, h6 {
  font-weight: 600;
  color: var(--color-gray-900);
  line-height: 1.3;
}

/* Layout */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 2rem;
}

/* Navigation - Clean */
.navbar {
  background: rgba(255, 255, 255, 0.95) !important;
  backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--color-gray-200);
  box-shadow: var(--shadow-sm);
}

.navbar-brand {
  font-weight: 700 !important;
  font-size: 1.75rem !important;
  color: var(--color-gray-900) !important;
}

.nav-link {
  font-weight: 500 !important;
  color: var(--color-gray-600) !important;
  margin: 0 0.5rem !important;
  transition: color 0.2s ease;
}

.nav-link:hover {
  color: var(--color-primary) !important;
}

/* Hero Section - Refined */
.hero {
  background: linear-gradient(135deg, var(--color-white) 0%, var(--color-gray-50) 100%);
  padding: 5rem 0 3rem;
  text-align: center;
  border-bottom: 1px solid var(--color-gray-200);
}

.hero h1 {
  font-size: 4rem;
  font-weight: 800;
  color: var(--color-gray-900);
  margin-bottom: 1.5rem;
  line-height: 1.1;
}

.hero .subtitle {
  font-size: 1.25rem;
  color: var(--color-gray-600);
  margin-bottom: 2rem;
  max-width: 700px;
  margin-left: auto;
  margin-right: auto;
}

.hero .badges {
  margin-bottom: 2.5rem;
}

.badge {
  background: var(--color-primary);
  color: white;
  padding: 0.5rem 1.25rem;
  border-radius: 25px;
  font-size: 0.875rem;
  font-weight: 500;
  margin: 0 0.5rem;
  display: inline-block;
  box-shadow: var(--shadow-sm);
}

/* Stats Section - Clean Cards */
.stats {
  background: var(--color-white);
  padding: 4rem 0;
  border-bottom: 1px solid var(--color-gray-200);
}

.stat-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 2rem;
  max-width: 1000px;
  margin: 0 auto;
  padding: 0 2rem;
}

.stat-item {
  background: var(--color-white);
  padding: 2rem 1.5rem;
  border-radius: 12px;
  border: 1px solid var(--color-gray-200);
  box-shadow: var(--shadow-md);
  text-align: center;
  transition: all 0.3s ease;
}

.stat-item:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}

.stat-number {
  font-size: 3rem;
  font-weight: 800;
  color: var(--color-primary);
  display: block;
  margin-bottom: 0.5rem;
  line-height: 1;
}

.stat-label {
  color: var(--color-gray-500);
  font-size: 0.875rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  font-weight: 600;
}

/* Grid Layouts */
.grid {
  display: grid;
  gap: 2rem;
  margin: 3rem 0;
}

.grid-2 {
  grid-template-columns: repeat(auto-fit, minmax(450px, 1fr));
}

.grid-3 {
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
}

/* Cards - Enhanced */
.card {
  background: var(--color-white);
  border: 1px solid var(--color-gray-200);
  border-radius: 12px;
  padding: 2rem;
  box-shadow: var(--shadow-md);
  transition: all 0.3s ease;
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}

.card h3 {
  color: var(--color-gray-900);
  margin-bottom: 1rem;
  font-size: 1.25rem;
}

.card img {
  width: 100%;
  height: 200px;
  object-fit: cover;
  border-radius: 8px;
  margin-bottom: 1.5rem;
}

/* Tables - Clean styling */
.table-container {
  margin: 3rem 0;
  border-radius: 12px;
  overflow: hidden;
  box-shadow: var(--shadow-md);
  border: 1px solid var(--color-gray-200);
  background: var(--color-white);
}

table {
  width: 100%;
  border-collapse: collapse;
  margin: 0;
  background: var(--color-white);
}

th {
  background: var(--color-gray-50);
  padding: 1.25rem 1.5rem;
  font-weight: 600;
  color: var(--color-gray-800);
  border-bottom: 2px solid var(--color-gray-200);
  text-align: left;
  font-size: 0.875rem;
}

td {
  padding: 1rem 1.5rem;
  border-bottom: 1px solid var(--color-gray-100);
  color: var(--color-gray-700);
  font-weight: 500;
}

tbody tr:hover {
  background: var(--color-gray-50);
}

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

/* Buttons - Clean design */
.btn-group {
  text-align: center;
  margin: 3rem 0;
}

.btn {
  display: inline-block;
  padding: 1rem 2rem;
  background: var(--color-primary);
  color: white;
  text-decoration: none;
  border-radius: 8px;
  font-weight: 600;
  margin: 0.5rem;
  transition: all 0.3s ease;
  border: none;
  font-size: 1rem;
  box-shadow: var(--shadow-sm);
}

.btn:hover {
  background: #2563eb;
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
  color: white;
  text-decoration: none;
}

/* Abstract & Content Areas */
.abstract {
  background: var(--color-white);
  padding: 3rem;
  border-radius: 12px;
  margin: 3rem 0;
  border-left: 4px solid var(--color-primary);
  box-shadow: var(--shadow-md);
}

.abstract p {
  margin-bottom: 1.5rem;
  color: var(--color-gray-700);
  line-height: 1.7;
}

/* Authors Section */
.authors {
  background: var(--color-white);
  padding: 3rem;
  border-radius: 12px;
  margin: 3rem 0;
  border: 1px solid var(--color-gray-200);
  box-shadow: var(--shadow-md);
}

.author-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 2rem;
  margin-top: 2rem;
}

.author {
  text-align: center;
  padding: 1.5rem;
  background: var(--color-gray-50);
  border-radius: 8px;
  transition: all 0.3s ease;
}

.author:hover {
  background: var(--color-white);
  box-shadow: var(--shadow-sm);
  transform: translateY(-2px);
}

.author-name {
  font-weight: 600;
  color: var(--color-gray-900);
  margin-bottom: 0.5rem;
}

.author-affiliation {
  color: var(--color-gray-500);
  font-size: 0.875rem;
  font-weight: 500;
}

/* Figures */
.figure {
  text-align: center;
  margin: 3rem 0;
}

.figure img {
  max-width: 100%;
  height: auto;
  border-radius: 12px;
  box-shadow: var(--shadow-lg);
}

.figure-caption {
  margin-top: 1.5rem;
  color: var(--color-gray-500);
  font-style: italic;
  font-size: 0.9rem;
  font-weight: 500;
}

/* Code Blocks */
pre {
  background: var(--color-gray-900);
  color: var(--color-gray-100);
  border-radius: 12px;
  padding: 2rem;
  overflow-x: auto;
  font-size: 0.875rem;
  line-height: 1.7;
  margin: 2rem 0;
  box-shadow: var(--shadow-md);
}

code {
  background: var(--color-gray-100);
  color: var(--color-gray-700);
  padding: 0.25rem 0.5rem;
  border-radius: 4px;
  font-size: 0.875em;
  font-weight: 500;
}

/* Section Styling */
section {
  margin: 4rem 0;
}

h2 {
  margin-top: 4rem;
  margin-bottom: 2rem;
  padding-bottom: 1rem;
  border-bottom: 2px solid var(--color-gray-200);
  color: var(--color-gray-900);
  font-size: 2.25rem;
}

h3 {
  margin-top: 3rem;
  margin-bottom: 1.5rem;
  color: var(--color-gray-900);
  font-size: 1.5rem;
}

/* Performance highlighting */
.best {
  background: #dcfce7 !important;
  font-weight: 700;
  color: #166534;
}

.second-best {
  background: #fef3c7 !important;
  font-weight: 700;
  color: #92400e;
}

/* Lists */
ul, ol {
  margin: 2rem 0;
  padding-left: 2rem;
}

li {
  margin-bottom: 0.75rem;
  color: var(--color-gray-700);
  line-height: 1.6;
}

/* Responsive Design */
@media (max-width: 768px) {
  .container {
    padding: 0 1rem;
  }
  
  .hero {
    padding: 4rem 0 3rem;
  }
  
  .hero h1 {
    font-size: 2.5rem;
  }
  
  .hero .subtitle {
    font-size: 1.1rem;
  }
  
  .stat-grid {
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1.5rem;
    padding: 0 1rem;
  }
  
  .stat-number {
    font-size: 2.5rem;
  }
  
  .grid-2,
  .grid-3 {
    grid-template-columns: 1fr;
  }
  
  .card {
    padding: 1.5rem;
  }
  
  .abstract,
  .authors {
    padding: 2rem;
  }
  
  th, td {
    padding: 0.75rem 1rem;
    font-size: 0.875rem;
  }
  
  h2 {
    font-size: 2rem;
    margin-top: 3rem;
  }
  
  section {
    margin: 3rem 0;
  }
}