:root {
  /* Dynamic themes using CSS variables */
  --primary: #6366F1;
  --primary-hover: #4F46E5;
  --secondary: #8B5CF6;
  --accent: #22D3EE;
  
  --success: #10B981;
  --warning: #F59E0B;
  --danger: #EF4444;
  
  /* Shared Base */
  --border-radius: 12px;
  --font-family: 'Inter', system-ui, -apple-system, sans-serif;
  --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --shadow-color: rgba(0, 0, 0, 0.2);
  
  /* Dark Mode Default */
  --bg-color: #0F172A;
  --surface-color: rgba(30, 41, 59, 0.6);
  --surface-border: rgba(255, 255, 255, 0.08);
  --text-primary: #F8FAFC;
  --text-muted: #94A3B8;
  --input-bg: rgba(15, 23, 42, 0.7);
  --hover-bg: rgba(255, 255, 255, 0.05);
}

.light-mode {
  --bg-color: #F8FAFC;
  --surface-color: rgba(255, 255, 255, 0.8);
  --surface-border: rgba(0, 0, 0, 0.08);
  --text-primary: #0F172A;
  --text-muted: #64748B;
  --input-bg: rgba(255, 255, 255, 1);
  --hover-bg: rgba(0, 0, 0, 0.05);
  --shadow-color: rgba(0, 0, 0, 0.05);
}

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

body {
  font-family: var(--font-family);
  background-color: var(--bg-color);
  color: var(--text-primary);
  min-height: 100vh;
  transition: background-color var(--transition), color var(--transition);
  overflow-x: hidden;
}

/* Utilities */
.hidden { display: none !important; }
.fade-in { animation: fadeIn 0.5s ease; }
.text-xs { font-size: 0.75rem; }
.text-sm { font-size: 0.875rem; }
.text-muted { color: var(--text-muted); }
.text-primary { color: var(--primary); }
.text-success { color: var(--success); }
.text-warning { color: var(--warning); }
.text-danger { color: var(--danger); }
.uppercase { text-transform: uppercase; letter-spacing: 0.05em; }
.mt-4 { margin-top: 1.5rem; }
.mb-4 { margin-bottom: 1.5rem; }

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(10px); }
  to { opacity: 1; transform: translateY(0); }
}

/* Glassmorphism */
.glass-panel {
  background: var(--surface-color);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border: 1px solid var(--surface-border);
  box-shadow: 0 4px 20px var(--shadow-color);
  border-radius: var(--border-radius);
}

.glass-input, .glass-select {
  background: var(--input-bg);
  border: 1px solid var(--surface-border);
  color: var(--text-primary);
  border-radius: 8px;
  padding: 0.75rem 1rem;
  font-family: var(--font-family);
  font-size: 1rem;
  outline: none;
  transition: var(--transition);
}

.glass-input:focus, .glass-select:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.2);
}

.glass-select {
  padding: 0.5rem;
  font-size: 0.875rem;
  cursor: pointer;
}

/* Layout */
.navbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 2rem;
  position: sticky;
  top: 0;
  z-index: 100;
  border-radius: 0;
  border-top: none;
  border-left: none;
  border-right: none;
}

.logo {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  color: var(--primary);
}

.logo h1 {
  font-size: 1.25rem;
  font-weight: 700;
  background: linear-gradient(135deg, var(--primary), var(--accent));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.nav-controls {
  display: flex;
  align-items: center;
  gap: 1.5rem;
}

.export-group {
  display: flex;
  gap: 0.5rem;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 2rem;
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.75rem 1.5rem;
  border-radius: 8px;
  font-weight: 600;
  font-family: var(--font-family);
  font-size: 0.875rem;
  cursor: pointer;
  transition: var(--transition);
  border: 1px solid transparent;
}

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.btn-sm {
  padding: 0.5rem 1rem;
  font-size: 0.75rem;
}

.btn-primary {
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  color: white;
  box-shadow: 0 4px 12px rgba(99, 102, 241, 0.3);
}

.btn-primary:hover:not(:disabled) {
  box-shadow: 0 6px 16px rgba(99, 102, 241, 0.5);
  transform: translateY(-1px);
}

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

.btn-outline:hover:not(:disabled) {
  border-color: var(--primary);
  color: var(--primary);
  background: rgba(99, 102, 241, 0.05);
}

.icon-btn {
  background: transparent;
  border: none;
  color: var(--text-muted);
  width: 36px;
  height: 36px;
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: var(--transition);
}

.icon-btn:hover {
  background: var(--hover-bg);
  color: var(--text-primary);
}

/* Input Section */
.input-section {
  padding: 1.5rem;
}

.repo-form {
  display: flex;
  gap: 1rem;
}

.input-group {
  position: relative;
  flex: 1;
}

.input-icon {
  position: absolute;
  left: 1rem;
  top: 50%;
  transform: translateY(-50%);
  color: var(--text-muted);
}

.input-group input {
  padding-left: 3rem;
  width: 100%;
}

.loading {
  display: flex;
  align-items: center;
  gap: 1rem;
  margin-top: 1rem;
  color: var(--text-muted);
  font-weight: 500;
}

.spinner {
  width: 20px;
  height: 20px;
  border: 2px solid var(--surface-border);
  border-top-color: var(--primary);
  border-radius: 50%;
  animation: spin 1s linear infinite;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

.error-msg {
  color: var(--danger);
  margin-top: 1rem;
  padding: 0.75rem;
  background: rgba(239, 68, 68, 0.1);
  border-radius: 8px;
  border: 1px solid rgba(239, 68, 68, 0.2);
  font-size: 0.875rem;
}

/* Metrics Grid */
.metrics-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 1.5rem;
}

.metric-card {
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.metric-value {
  font-size: 2.25rem;
  font-weight: 700;
  line-height: 1.1;
  color: var(--text-primary);
}

.split-val {
  display: flex;
  gap: 1rem;
}

.metric-trend {
  font-size: 0.875rem;
  color: var(--text-muted);
}

.card-header-flex {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.health-indicator {
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--surface-border);
}

.health-good { background: var(--success); box-shadow: 0 0 8px var(--success); }
.health-warn { background: var(--warning); box-shadow: 0 0 8px var(--warning); }
.health-danger { background: var(--danger); box-shadow: 0 0 8px var(--danger); }

/* Charts Area */
.charts-grid-main {
  display: grid;
  grid-template-columns: 2fr 1fr;
  gap: 1.5rem;
}

.charts-grid-secondary {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.5rem;
}

.chart-container {
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.chart-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.chart-header h3 {
  font-size: 1.125rem;
  font-weight: 600;
}

.canvas-wrapper {
  position: relative;
  width: 100%;
}

/* Leaderboard */
.list-container {
  max-height: 400px;
}

.leaderboard-list {
  list-style: none;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  padding-right: 0.5rem;
}

/* custom scrollbar for leaderboard */
.leaderboard-list::-webkit-scrollbar {
  width: 6px;
}
.leaderboard-list::-webkit-scrollbar-track {
  background: var(--input-bg);
  border-radius: 10px;
}
.leaderboard-list::-webkit-scrollbar-thumb {
  background: var(--surface-border);
  border-radius: 10px;
}

.leaderboard-item {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 0.75rem;
  background: var(--input-bg);
  border-radius: 8px;
  border: 1px solid var(--surface-border);
  transition: var(--transition);
}

.leaderboard-item:hover {
  border-color: var(--primary);
  transform: translateX(4px);
}

.avatar {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: var(--surface-border);
  object-fit: cover;
}

.user-info {
  flex: 1;
  display: flex;
  flex-direction: column;
}

.user-name {
  font-weight: 600;
  font-size: 0.875rem;
}

.user-stats {
  font-size: 0.75rem;
  color: var(--text-muted);
}

.user-rank {
  font-weight: 700;
  font-size: 1rem;
  color: var(--primary);
  min-width: 24px;
  text-align: center;
}

/* Empty State */
.empty-state {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 4rem 2rem;
  height: 60vh;
}

.empty-state h2 {
  font-size: 1.5rem;
  margin-bottom: 0.5rem;
}

.empty-state p {
  max-width: 400px;
}

/* Toast */
.toast {
  position: fixed;
  bottom: 2rem;
  left: 50%;
  transform: translateX(-50%) translateY(0);
  background: var(--text-primary);
  color: var(--bg-color);
  padding: 0.75rem 1.5rem;
  border-radius: 999px;
  font-size: 0.875rem;
  font-weight: 600;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.4);
  z-index: 1000;
  transition: transform 0.3s, opacity 0.3s;
}

.toast.hidden {
  transform: translateX(-50%) translateY(20px);
  opacity: 0;
  pointer-events: none;
  display: block !important;
}

/* Responsive */
@media (max-width: 900px) {
  .charts-grid-main, .charts-grid-secondary {
    grid-template-columns: 1fr;
  }
  
  .repo-form {
    flex-direction: column;
  }
  
  .chart-container.span-2 {
    grid-column: span 1;
  }
}