:root {
  --bg: #f5f7fa;
  --fg: #2c3e50;
  --accent: #3498db;
  --card-bg: #ffffff;
  --shadow-light: rgba(0, 0, 0, 0.1);
  --shadow-medium: rgba(0, 0, 0, 0.15);
  --border: #e1e8ed;
  --success: #27ae60;
  --warning: #f39c12;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen', 
               'Ubuntu', 'Cantarell', 'Fira Sans', 'Droid Sans', 'Helvetica Neue', 
               sans-serif;
  background: var(--bg);
  color: var(--fg);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

header, main, footer {
  max-width: 1200px;
  margin: 0 auto;
  padding: 2rem 1rem;
}

header {
  text-align: center;
  padding: 3rem 1rem 2rem;
}

header h1 {
  color: var(--accent);
  font-size: 2.5rem;
  margin: 0;
  font-weight: 700;
}

header p {
  color: #7f8c8d;
  font-size: 1.1rem;
  margin: 0.5rem 0 0;
}

main h2 {
  color: var(--fg);
  font-size: 1.8rem;
  margin-bottom: 2rem;
  text-align: center;
  font-weight: 600;
}

/* Grid layout for repository cards */
.repo-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 2rem;
  margin: 2rem 0;
}

/* Repository card styling */
.repo-card {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 1.5rem;
  transition: all 0.3s ease;
  box-shadow: 0 2px 8px var(--shadow-light);
  display: flex;
  flex-direction: column;
  height: 100%;
}

.repo-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 8px 24px var(--shadow-medium);
  border-color: var(--accent);
}

.repo-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  margin-bottom: 0.75rem;
  gap: 1rem;
}

.repo-name {
  margin: 0;
  font-size: 1.25rem;
  font-weight: 600;
  flex: 1;
  word-break: break-word;
}

.repo-name a {
  color: var(--accent);
  text-decoration: none;
  transition: color 0.2s ease;
}

.repo-name a:hover {
  color: #2980b9;
  text-decoration: underline;
}

.repo-stars {
  background: var(--warning);
  color: white;
  padding: 0.25rem 0.5rem;
  border-radius: 12px;
  font-size: 0.85rem;
  white-space: nowrap;
  font-weight: 500;
}

.repo-description {
  color: #5a6c7d;
  font-size: 0.95rem;
  margin: 0 0 1rem;
  flex: 1;
  line-height: 1.5;
}

.repo-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.85rem;
  color: #95a5a6;
  padding-top: 1rem;
  border-top: 1px solid var(--border);
  gap: 1rem;
  flex-wrap: wrap;
}

.repo-language {
  display: flex;
  align-items: center;
  font-weight: 500;
  color: var(--success);
}

.repo-language::before {
  content: '●';
  margin-right: 0.5rem;
  font-size: 1.2rem;
}

.repo-updated {
  color: #95a5a6;
}

/* Loading and error states */
.loading, .no-repos, .error {
  text-align: center;
  padding: 3rem 1rem;
  color: #7f8c8d;
  font-size: 1.1rem;
  grid-column: 1 / -1;
}

.error {
  color: #e74c3c;
}

/* Footer styling */
footer {
  text-align: center;
  padding: 2rem 1rem;
  color: #95a5a6;
}

footer a {
  color: var(--accent);
  text-decoration: none;
  transition: color 0.2s ease;
}

footer a:hover {
  color: #2980b9;
  text-decoration: underline;
}

/* Responsive design */
@media (max-width: 768px) {
  header h1 {
    font-size: 2rem;
  }
  
  main h2 {
    font-size: 1.5rem;
  }
  
  .repo-grid {
    grid-template-columns: 1fr;
    gap: 1.5rem;
  }
  
  .repo-card {
    padding: 1.25rem;
  }
}