/* Design System - Base Styles with Dark/Light Mode Support */

:root {
  /* Light Mode Colors */
  --bg-primary: #ffffff;
  --bg-secondary: #f8f9fa;
  --bg-secondary-rgb: 248, 249, 250;
  --bg-tertiary: #e9ecef;
  --text-primary: #1f2937;
  --text-secondary: #6b7280;
  --text-tertiary: #9ca3af;
  --border-color: #e5e7eb;
  --border-hover: #d1d5db;
  
  /* Brand Colors */
  --primary: #3b82f6;
  --primary-hover: #2563eb;
  --primary-light: #dbeafe;
  --success: #10b981;
  --success-hover: #059669;
  --success-light: #d1fae5;
  --danger: #ef4444;
  --danger-hover: #dc2626;
  --danger-light: #fee2e2;
  --warning: #f59e0b;
  --warning-light: #fef3c7;
  
  /* 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);
  
  /* Spacing */
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2rem;
  --spacing-2xl: 3rem;
  
  /* Border Radius */
  --radius-sm: 0.25rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
  
  /* Transitions */
  --transition-fast: 150ms ease-in-out;
  --transition-base: 200ms ease-in-out;
  --transition-slow: 300ms ease-in-out;
  color-scheme: light;
}

/* Dark Mode (follows OS setting) */
@media (prefers-color-scheme: dark) {
  :root {
    --bg-primary: #111827;
    --bg-secondary: #1f2937;
    --bg-secondary-rgb: 31, 41, 55;
    --bg-tertiary: #374151;
    --text-primary: #f9fafb;
    --text-secondary: #d1d5db;
    --text-tertiary: #9ca3af;
    --border-color: #374151;
    --border-hover: #4b5563;
    
    --primary: #60a5fa;
    --primary-hover: #3b82f6;
    --primary-light: #1e3a8a;
    --success: #34d399;
    --success-hover: #10b981;
    --success-light: #065f46;
    --danger: #f87171;
    --danger-hover: #ef4444;
    --danger-light: #7f1d1d;
    
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.4), 0 2px 4px -1px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.5), 0 4px 6px -2px rgba(0, 0, 0, 0.4);
    color-scheme: dark;
  }
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  transition: background-color var(--transition-base), color var(--transition-base);
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
  font-weight: 600;
  line-height: 1.2;
  margin-bottom: var(--spacing-md);
  color: var(--text-primary);
}

h1 { font-size: 2rem; }
h2 { font-size: 1.75rem; }
h3 { font-size: 1.5rem; }
h4 { font-size: 1.25rem; }
h5 { font-size: 1.125rem; }
h6 { font-size: 1rem; }

p {
  margin-bottom: var(--spacing-md);
  color: var(--text-secondary);
}

a {
  color: var(--primary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

a:hover {
  color: var(--primary-hover);
}

/* Layout */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--spacing-md);
}

@media (min-width: 768px) {
  .container {
    padding: 0 var(--spacing-xl);
  }
}

/* Navigation */
.navbar {
  background-color: var(--bg-secondary);
  border-bottom: 1px solid var(--border-color);
  padding: var(--spacing-md) 0;
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(10px);
  background-color: rgba(var(--bg-secondary-rgb, 248, 249, 250), 0.8);
}

.navbar-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--spacing-md);
}

@media (min-width: 768px) {
  .navbar-content {
    padding: 0 var(--spacing-xl);
  }
}

.navbar-brand {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--text-primary);
}

.navbar-links {
  display: flex;
  gap: var(--spacing-lg);
  align-items: center;
  list-style: none;
}

.navbar-links a {
  color: var(--text-secondary);
  font-weight: 500;
  padding: var(--spacing-sm) var(--spacing-md);
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
}

.navbar-links a:hover {
  color: var(--text-primary);
  background-color: var(--bg-tertiary);
}

.navbar-actions {
  display: flex;
  gap: var(--spacing-md);
  align-items: center;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: var(--spacing-sm) var(--spacing-lg);
  font-size: 0.875rem;
  font-weight: 500;
  border: none;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all var(--transition-fast);
  text-decoration: none;
  line-height: 1.5;
}

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

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

.btn-primary:hover:not(:disabled) {
  background-color: var(--primary-hover);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

.btn-secondary {
  background-color: var(--bg-tertiary);
  color: var(--text-primary);
}

.btn-secondary:hover:not(:disabled) {
  background-color: var(--border-color);
}

.btn-success {
  background-color: var(--success);
  color: white;
}

.btn-success:hover:not(:disabled) {
  background-color: var(--success-hover);
}

.btn-danger {
  background-color: var(--danger);
  color: white;
}

.btn-danger:hover:not(:disabled) {
  background-color: var(--danger-hover);
}

.btn-outline {
  background-color: transparent;
  border: 1px solid var(--border-color);
  color: var(--text-primary);
}

.btn-outline:hover:not(:disabled) {
  background-color: var(--bg-tertiary);
  border-color: var(--border-hover);
}

.btn-sm {
  padding: var(--spacing-xs) var(--spacing-md);
  font-size: 0.75rem;
}

.btn-lg {
  padding: var(--spacing-md) var(--spacing-xl);
  font-size: 1rem;
}

/* Forms */
.form-group {
  margin-bottom: var(--spacing-lg);
}

.form-label {
  display: block;
  margin-bottom: var(--spacing-sm);
  font-weight: 500;
  color: var(--text-primary);
  font-size: 0.875rem;
}

.form-control {
  width: 100%;
  padding: var(--spacing-sm) var(--spacing-md);
  font-size: 0.875rem;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  transition: all var(--transition-fast);
}

.form-control:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px var(--primary-light);
}

.form-control::placeholder {
  color: var(--text-tertiary);
}

.form-select {
  background-image: url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 16 16'%3e%3cpath fill='none' stroke='%23343a40' stroke-linecap='round' stroke-linejoin='round' stroke-width='2' d='M2 5l6 6 6-6'/%3e%3c/svg%3e");
  background-repeat: no-repeat;
  background-position: right 0.75rem center;
  background-size: 16px 12px;
  padding-right: 2.5rem;
  appearance: none;
}

textarea.form-control {
  resize: vertical;
  min-height: 100px;
}

.form-error {
  color: var(--danger);
  font-size: 0.75rem;
  margin-top: var(--spacing-xs);
  display: block;
}

.form-help {
  color: var(--text-tertiary);
  font-size: 0.75rem;
  margin-top: var(--spacing-xs);
  display: block;
}

/* Cards */
.card {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: var(--spacing-lg);
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-base);
}

.card:hover {
  box-shadow: var(--shadow-md);
}

.card-header {
  margin-bottom: var(--spacing-md);
  padding-bottom: var(--spacing-md);
  border-bottom: 1px solid var(--border-color);
}

.card-title {
  margin: 0;
  font-size: 1.25rem;
}

/* Tables */
.table-container {
  overflow-x: auto;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-color);
}

table {
  width: 100%;
  border-collapse: collapse;
  background-color: var(--bg-secondary);
}

thead {
  background-color: var(--bg-tertiary);
}

th, td {
  padding: var(--spacing-md);
  text-align: left;
  border-bottom: 1px solid var(--border-color);
}

th {
  font-weight: 600;
  color: var(--text-primary);
  font-size: 0.875rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

tbody tr:hover {
  background-color: var(--bg-tertiary);
}

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

/* Alerts */
.alert {
  padding: var(--spacing-md);
  border-radius: var(--radius-md);
  margin-bottom: var(--spacing-lg);
  border: 1px solid;
}

.alert-success {
  background-color: var(--success-light);
  border-color: var(--success);
  color: var(--success-hover);
}

.alert-error {
  background-color: var(--danger-light);
  border-color: var(--danger);
  color: var(--danger-hover);
}

.alert-info {
  background-color: var(--primary-light);
  border-color: var(--primary);
  color: var(--primary-hover);
}

/* Utilities */
.text-center {
  text-align: center;
}

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

.mt-1 { margin-top: var(--spacing-sm); }
.mt-2 { margin-top: var(--spacing-md); }
.mt-3 { margin-top: var(--spacing-lg); }
.mb-1 { margin-bottom: var(--spacing-sm); }
.mb-2 { margin-bottom: var(--spacing-md); }
.mb-3 { margin-bottom: var(--spacing-lg); }

.d-flex {
  display: flex;
}

.flex-column {
  flex-direction: column;
}

.gap-1 { gap: var(--spacing-sm); }
.gap-2 { gap: var(--spacing-md); }
.gap-3 { gap: var(--spacing-lg); }

.justify-between {
  justify-content: space-between;
}

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

.hidden {
  display: none !important;
}

/* Responsive */
@media (max-width: 767px) {
  .navbar-links {
    flex-direction: column;
    gap: var(--spacing-sm);
  }
  
  .navbar-content {
    flex-direction: column;
    gap: var(--spacing-md);
  }
  
  .container {
    padding: 0 var(--spacing-md);
  }
  
  table {
    font-size: 0.875rem;
  }
  
  th, td {
    padding: var(--spacing-sm);
  }
}