/* design-tokens.css */
:root {
  /* Spacing Tokens (4px baseline) */
  --space-1: 4px;
  --space-2: 8px;
  --space-3: 12px;
  --space-4: 16px;
  --space-5: 20px;
  --space-6: 24px;
  --space-8: 32px;
  --space-10: 40px;

  /* Base Colors - Light Mode */
  --colour-surface: #ffffff;
  --colour-surface-alt: #f9fafb; /* subtle background for cards/sections */
  --colour-muted-surface: #f3f4f6; /* zebra striping */
  --colour-border: #e5e7eb;
  --colour-text: #1f2937;
  --colour-text-muted: #6b7280;

  /* Brand Colors */
  --colour-primary: #ea580c; /* vibrant orange accent */
  --colour-primary-hover: #c2410c;
  --colour-secondary: #1e3a8a; /* deep blue for trust */

  /* Semantic Colors */
  --colour-success: #10b981;
  --colour-warning: #f59e0b;
  --colour-error: #ef4444;
  --colour-info: #3b82f6;

  /* Typography */
  --font-family-sans: 'Inter', 'Roboto', 'Helvetica Neue', Arial, sans-serif;
  
  /* Component Variables */
  --border-radius-sm: 4px; /* forms */
  --border-radius-md: 6px; /* buttons */
  --border-radius-lg: 8px; /* cards, modals */
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.1);
  --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.1), 0 2px 4px -1px rgba(0,0,0,0.06);
  --transition-fast: 0.15s ease-in-out;
  --transition-normal: 0.2s ease-in-out;
}

/* Dark Mode Tokens */
html.dark:root, body.dark {
  --colour-surface: #111827;
  --colour-surface-alt: #1f2937;
  --colour-muted-surface: #374151;
  --colour-border: #4b5563;
  --colour-text: #f9fafb;
  --colour-text-muted: #9ca3af;

  --colour-primary: #f97316;
  --colour-primary-hover: #ea580c;
  --colour-secondary: #60a5fa;

  --shadow-sm: 0 1px 3px rgba(0,0,0,0.5);
  --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.5), 0 2px 4px -1px rgba(0,0,0,0.3);
}

/* Base Styles enforcing Design System */
body {
  font-family: var(--font-family-sans);
  background-color: var(--colour-surface-alt);
  color: var(--colour-text);
  line-height: 1.5;
  transition: background-color var(--transition-normal), color var(--transition-normal);
}

/* Typography Scale */
h1 { font-size: 2.25rem; font-weight: 700; margin-top: 2em; margin-bottom: 1em; }
h2 { font-size: 1.875rem; font-weight: 600; margin-top: 1.75em; margin-bottom: 0.75em; }
h3 { font-size: 1.5rem; font-weight: 600; margin-top: 1.5em; margin-bottom: 0.75em; }
h4 { font-size: 1.25rem; font-weight: 600; margin-top: 1.25em; margin-bottom: 0.5em; }
h5 { font-size: 1.125rem; font-weight: 500; margin-top: 1em; margin-bottom: 0.5em; }
h6 { font-size: 1rem; font-weight: 500; margin-top: 1em; margin-bottom: 0.5em; }
p { margin-bottom: 1em; }
caption, .text-tiny { font-size: 0.875rem; color: var(--colour-text-muted); }

/* Buttons */
.button-primary, .button-secondary, .button-outline, .button-ghost {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--border-radius-md);
  font-weight: 500;
  letter-spacing: 0.5px;
  text-transform: uppercase;
  padding: 0 var(--space-4);
  height: 40px;
  transition: all var(--transition-normal);
  cursor: pointer;
  border: 1px solid transparent;
  font-size: 0.875rem;
  text-decoration: none;
}
@media (max-width: 768px) {
  .button-primary, .button-secondary, .button-outline, .button-ghost {
    height: 48px;
  }
}

.button-primary {
  background-color: var(--colour-primary);
  color: #ffffff;
}
.button-primary:hover {
  background-color: var(--colour-primary-hover);
  transform: translateY(-1px);
}
.button-secondary {
  background-color: var(--colour-secondary);
  color: #ffffff;
}
.button-secondary:hover {
  opacity: 0.9;
  transform: translateY(-1px);
}
.button-outline {
  background-color: transparent;
  border-color: var(--colour-primary);
  color: var(--colour-primary);
}
.button-outline:hover {
  background-color: rgba(234, 88, 12, 0.1);
}
.button-ghost {
  background-color: transparent;
  color: var(--colour-text);
}
.button-ghost:hover {
  background-color: var(--colour-muted-surface);
}

/* Forms */
input[type="text"], input[type="email"], input[type="password"], textarea, select {
  border: 1px solid var(--colour-border);
  border-radius: var(--border-radius-sm);
  padding: var(--space-3) var(--space-4);
  background-color: var(--colour-surface);
  color: var(--colour-text);
  font-family: var(--font-family-sans);
  transition: border-color var(--transition-normal), box-shadow var(--transition-normal);
  width: 100%;
}
input:focus, textarea:focus, select:focus {
  outline: none;
  border-color: var(--colour-primary);
  box-shadow: 0 0 0 3px rgba(234, 88, 12, 0.2);
}
.form-error {
  color: var(--colour-error);
  font-size: 12px;
  margin-top: var(--space-1);
}

/* Cards & Containers */
.card {
  background-color: var(--colour-surface);
  border: 1px solid var(--colour-border);
  border-radius: var(--border-radius-lg);
  box-shadow: var(--shadow-sm);
  padding: var(--space-4);
  transition: transform var(--transition-normal), box-shadow var(--transition-normal);
}
.card > * + * {
  margin-top: var(--space-3);
}

/* Modals & Overlays */
.modal-backdrop {
  position: fixed;
  top: 0; left: 0; right: 0; bottom: 0;
  background-color: rgba(0,0,0,0.5);
  z-index: 1000;
  display: flex;
  align-items: center;
  justify-content: center;
}
html.dark .modal-backdrop {
  background-color: rgba(0,0,0,0.4);
}
.modal-container {
  background-color: var(--colour-surface);
  max-width: 600px;
  width: 100%;
  border-radius: var(--border-radius-lg);
  padding: var(--space-6);
  box-shadow: var(--shadow-md);
  position: relative;
  animation: modal-fade-in var(--transition-fast);
}
@keyframes modal-fade-in {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: translateY(0); }
}
.modal-close {
  position: absolute;
  top: var(--space-4);
  right: var(--space-4);
  width: 24px; height: 24px;
  cursor: pointer;
  color: var(--colour-text-muted);
}
.modal-close:hover {
  color: var(--colour-text);
}

/* Tables */
table.data-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
}
table.data-table th {
  background-color: var(--colour-surface-alt);
  padding: var(--space-3) var(--space-4);
  border-bottom: 2px solid var(--colour-border);
  font-weight: 600;
  position: sticky;
  top: 0;
}
table.data-table td {
  padding: var(--space-3) var(--space-4);
  border-bottom: 1px solid var(--colour-border);
}
table.data-table tbody tr:nth-child(even) {
  background-color: var(--colour-muted-surface);
}

/* Grid System */
.grid-container {
  display: grid;
  grid-template-columns: repeat(12, 1fr);
  gap: var(--space-4);
  max-width: 1280px;
  margin: 0 auto;
}
@media (max-width: 768px) {
  .grid-container {
    grid-template-columns: 1fr;
  }
}