/**
 * Color Contrast Checker Styles
 * 
 * Uses CSS custom properties for dynamic color updates
 * and a clean, accessible design system.
 */

/* ============================================
   CSS Custom Properties
   ============================================ */
:root {
  /* Colors - All checked for WCAG AA contrast */
  --color-bg: #f8f9fa;
  --color-surface: #ffffff;
  --color-text: #1a1a2e;
  --color-text-muted: #545963;
  /* 7.0:1 on white, 5.5:1 on #f8f9fa - passes AA */
  --color-border: #dee2e6;
  --color-border-focus: #0056b3;
  /* Darker blue for better contrast */
  --color-success: #0d6a3c;
  /* Darker green: 5.9:1 on white - passes AA */
  --color-error: #c41c2d;
  /* Slightly darker: 5.5:1 on white - passes AA */
  --color-accent: #0056b3;
  /* 7.2:1 on white - passes AA */
  --color-focus-ring: #0056b3;

  /* Spacing */
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;

  /* Typography */
  --font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-mono: 'SF Mono', Monaco, 'Cascadia Code', Consolas, monospace;
  --font-size-sm: 0.875rem;
  --font-size-base: 1rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.5rem;
  --font-size-2xl: 2rem;

  /* Borders & Shadows */
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.07);
  --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.1);

  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-base: 250ms ease;
}

/* ============================================
   Reset & Base Styles
   ============================================ */
*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  margin: 0;
  padding: 0;
  font-family: var(--font-family);
  font-size: var(--font-size-base);
  line-height: 1.6;
  color: var(--color-text);
  background-color: var(--color-bg);
}

/* Visually hidden but accessible to screen readers */
.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* Skip link for keyboard navigation (WCAG 2.4.1) */
.skip-link {
  position: absolute;
  top: -100px;
  left: 50%;
  transform: translateX(-50%);
  padding: var(--space-md) var(--space-lg);
  background: var(--color-text);
  color: var(--color-surface);
  font-weight: 600;
  text-decoration: none;
  border-radius: var(--radius-md);
  z-index: 1001;
  transition: top var(--transition-fast);
}

.skip-link:focus {
  top: var(--space-md);
  outline: 3px solid var(--color-focus-ring);
  outline-offset: 2px;
}

/* ============================================
   Layout
   ============================================ */
.container {
  width: 100%;
  max-width: 900px;
  margin: 0 auto;
  padding: var(--space-lg);
}

/* ============================================
   Header
   ============================================ */
.header {
  text-align: center;
  margin-bottom: var(--space-2xl);
}

.logo-link {
  display: inline-block;
  margin-bottom: var(--space-lg);
  transition: opacity var(--transition-fast);
}

.logo-link:hover {
  opacity: 0.8;
}

.logo-link:focus-visible {
  outline: 3px solid var(--color-focus-ring);
  outline-offset: 4px;
  border-radius: var(--radius-sm);
}

.logo {
  display: block;
  height: 30px;
  width: auto;
  margin: 0 auto;
}

.header h1 {
  margin: 0 0 var(--space-sm);
  font-size: var(--font-size-2xl);
  font-weight: 700;
  color: var(--color-text);
}

.subtitle {
  margin: 0;
  color: var(--color-text-muted);
  font-size: var(--font-size-lg);
}

/* ============================================
   Input Section
   ============================================ */
.input-section {
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  padding: var(--space-xl);
  padding-top: calc(var(--space-xl) + 4px);
  /* Extra space for focus outlines */
  box-shadow: var(--shadow-md);
  margin-bottom: var(--space-xl);
}

.input-row {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: var(--space-lg);
  margin-bottom: var(--space-lg);
}

.color-input-group {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
  min-width: 0;
  /* Prevent grid blowout */
  /* Removed overflow: hidden to allow focus outlines to be visible */
}

.color-input-group label {
  font-weight: 600;
  font-size: var(--font-size-sm);
  color: var(--color-text);
}

.color-input-wrapper {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  position: relative;
  min-width: 0;
  /* Prevent flex overflow */
}

.color-picker {
  width: 44px;
  height: 44px;
  padding: 0;
  border: 2px solid var(--color-border);
  border-radius: var(--radius-md);
  cursor: pointer;
  flex-shrink: 0;
  transition: border-color var(--transition-fast);
  background: var(--color-surface);
  box-shadow: var(--shadow-sm);
}

.color-picker:hover {
  border-color: var(--color-border-focus);
}

.color-picker:focus {
  outline: 3px solid var(--color-focus-ring);
  outline-offset: 2px;
}

/* Remove default color picker styling */
.color-picker::-webkit-color-swatch-wrapper {
  padding: 2px;
}

.color-picker::-webkit-color-swatch {
  border: none;
  border-radius: var(--radius-sm);
}

.color-picker::-moz-color-swatch {
  border: none;
  border-radius: var(--radius-sm);
}

.hex-input {
  flex: 1;
  min-width: 0;
  /* Prevent flex item from overflowing */
  width: 100%;
  /* Ensure it respects container */
  height: 44px;
  padding: 0 var(--space-md);
  font-family: var(--font-mono);
  font-size: var(--font-size-base);
  border: 2px solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-surface);
  color: var(--color-text);
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.hex-input:hover {
  border-color: var(--color-border-focus);
}

.hex-input:focus {
  outline: 2px solid var(--color-focus-ring);
  outline-offset: 2px;
  border-color: var(--color-border-focus);
}

.hex-input:invalid {
  border-color: var(--color-error);
}

.error-message {
  position: absolute;
  bottom: -20px;
  left: 52px;
  font-size: 0.75rem;
  color: var(--color-error);
}

/* ============================================
   WCAG Selector
   ============================================ */
.wcag-selector {
  border-top: 1px solid var(--color-border);
  padding-top: var(--space-lg);
}

.wcag-selector fieldset {
  border: none;
  padding: 0;
  margin: 0;
}

.wcag-selector legend {
  font-weight: 600;
  font-size: var(--font-size-sm);
  color: var(--color-text);
  margin-bottom: var(--space-md);
}

.radio-group {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-md);
}

.radio-label {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-sm) var(--space-md);
  min-height: 44px;
  /* WCAG 2.5.8 Target Size - exceeds 24px minimum */
  border: 2px solid var(--color-border);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all var(--transition-fast);
  user-select: none;
}

.radio-label:hover {
  border-color: var(--color-border-focus);
  background: rgba(74, 144, 217, 0.05);
}

.radio-label:has(input:checked) {
  border-color: var(--color-accent);
  background: rgba(74, 144, 217, 0.1);
}

.radio-label:has(input:focus-visible) {
  outline: 3px solid var(--color-focus-ring);
  outline-offset: 2px;
}

.radio-label input {
  appearance: none;
  width: 18px;
  height: 18px;
  border: 2px solid var(--color-border);
  border-radius: 50%;
  margin: 0;
  cursor: pointer;
  position: relative;
  transition: all var(--transition-fast);
}

.radio-label input:checked {
  border-color: var(--color-accent);
  background: var(--color-accent);
}

.radio-label input:checked::after {
  content: '';
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 6px;
  height: 6px;
  background: white;
  border-radius: 50%;
}

.radio-text {
  font-weight: 500;
}

.ratio-hint {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  font-family: var(--font-mono);
}

/* ============================================
   Results Section
   ============================================ */
.results-section {
  margin-bottom: var(--space-xl);
}

.results-section h2 {
  font-size: var(--font-size-xl);
  font-weight: 700;
  margin: 0 0 var(--space-lg);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-text);
}

.results-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: var(--space-lg);
}

/* ============================================
   Result Cards
   ============================================ */
.result-card {
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
  box-shadow: var(--shadow-md);
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
}

.result-card h3 {
  margin: 0;
  font-size: var(--font-size-base);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-text);
  /* Use main text color for AA compliance */
}

.color-preview {
  aspect-ratio: 16 / 9;
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  border: 2px solid var(--color-border);
  transition: background-color var(--transition-base);
}

.preview-text {
  font-size: 2.5rem;
  font-weight: 700;
  transition: color var(--transition-base);
}

.contrast-info {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-md);
}

.contrast-ratio {
  font-family: var(--font-mono);
  font-size: var(--font-size-lg);
  font-weight: 600;
}

.pass-fail {
  padding: var(--space-xs) var(--space-sm);
  border-radius: var(--radius-sm);
  font-size: var(--font-size-sm);
  font-weight: 600;
  text-transform: uppercase;
}

.pass-fail.pass {
  background: rgba(13, 106, 60, 0.15);
  color: var(--color-success);
  border: 1px solid var(--color-success);
  /* Non-color indicator per WCAG 1.4.1 */
}

.pass-fail.fail {
  background: rgba(196, 28, 45, 0.15);
  color: var(--color-error);
  border: 1px solid var(--color-error);
  /* Non-color indicator per WCAG 1.4.1 */
}

/* ============================================
   Suggestions
   ============================================ */
.suggestion {
  border-top: 1px solid var(--color-border);
  padding-top: var(--space-md);
}

.suggestion p {
  margin: 0 0 var(--space-sm);
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
}

.suggested-color-wrapper {
  display: flex;
  align-items: center;
  gap: var(--space-md);
}

.suggested-preview {
  width: 60px;
  height: 60px;
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  border: 2px solid var(--color-border);
  flex-shrink: 0;
}

.suggested-preview .preview-text {
  font-size: 1.25rem;
}

.copy-btn {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-sm) var(--space-md);
  min-height: 44px;
  /* WCAG 2.5.8 Target Size - exceeds 24px minimum */
  background: var(--color-bg);
  border: 2px solid var(--color-border);
  border-radius: var(--radius-md);
  font-family: var(--font-mono);
  font-size: var(--font-size-base);
  color: var(--color-text);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.copy-btn:hover {
  border-color: var(--color-border-focus);
  background: var(--color-surface);
}

.copy-btn:focus-visible {
  outline: 3px solid var(--color-focus-ring);
  outline-offset: 2px;
}

.copy-btn:active {
  transform: scale(0.98);
}

.copy-icon {
  flex-shrink: 0;
  opacity: 0.6;
}

.suggested-ratio {
  display: block;
  margin-top: var(--space-sm);
  font-family: var(--font-mono);
  font-size: var(--font-size-sm);
  color: var(--color-success);
}

/* ============================================
   Universal Card
   ============================================ */
.universal-card {
  background: linear-gradient(135deg, var(--color-surface) 0%, #f0f4f8 100%);
}

.universal-desc {
  margin: 0;
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
}

.universal-preview-group {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-sm);
}

.universal-preview {
  aspect-ratio: 1;
}

.universal-info {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

.universal-copy {
  width: 100%;
  justify-content: center;
}

.universal-ratios {
  display: flex;
  justify-content: space-between;
  font-family: var(--font-mono);
  font-size: var(--font-size-sm);
  color: var(--color-success);
}

.no-universal {
  margin: 0;
  padding: var(--space-md);
  background: rgba(220, 53, 69, 0.1);
  border-radius: var(--radius-md);
  font-size: var(--font-size-sm);
  color: var(--color-error);
  text-align: center;
}

/* ============================================
   Toast Notification
   ============================================ */
.toast {
  position: fixed;
  bottom: var(--space-xl);
  left: 50%;
  transform: translateX(-50%) translateY(100px);
  padding: var(--space-md) var(--space-lg);
  background: var(--color-text);
  color: var(--color-surface);
  border-radius: var(--radius-md);
  font-size: var(--font-size-sm);
  font-weight: 500;
  box-shadow: var(--shadow-lg);
  opacity: 0;
  transition: transform var(--transition-base), opacity var(--transition-base);
  z-index: 1000;
}

.toast.visible {
  transform: translateX(-50%) translateY(0);
  opacity: 1;
}

/* ============================================
   Footer
   ============================================ */
.footer {
  text-align: center;
  padding: var(--space-sm);
  border-top: 1px solid var(--color-border);
}

.footer-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--space-md);
}

.footer p {
  margin: 0;
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
}

.footer .heart {
  color: var(--color-error);
}

.footer a {
  color: var(--color-accent);
  text-decoration: underline;
  /* Always underline links per WCAG 1.4.1 */
}

.footer a:hover {
  text-decoration-thickness: 2px;
}

.footer a:focus-visible {
  outline: 3px solid var(--color-focus-ring);
  outline-offset: 2px;
}

/* ============================================
   Responsive Adjustments
   ============================================ */
@media (max-width: 600px) {
  .container {
    padding: var(--space-md);
  }

  .header h1 {
    font-size: var(--font-size-xl);
  }

  .input-section {
    padding: var(--space-lg);
  }

  .input-row {
    grid-template-columns: 1fr;
  }

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

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

  .results-grid {
    grid-template-columns: 1fr;
  }

  .preview-text {
    font-size: 2rem;
  }

  .footer-row {
    flex-direction: column;
    justify-content: center;
    align-items: center;
  }

  .footer p:first-child {
    order: 2;
  }
}

/* ============================================
   Reduced Motion
   ============================================ */
@media (prefers-reduced-motion: reduce) {

  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}