/* Dark Mode CSS Variables and Styles */

/* Light theme (default) */
:root {
  --color-bg: #fff;
  --color-text: #000;
  --color-text-light: #777;
  --color-border: #ddd;
  --color-link: #0000ff;
  --color-link-hover: #000;
}

/* Dark theme */
[data-theme="dark"] {
  --color-bg: #1a1a1a;
  --color-text: #e0e0e0;
  --color-text-light: #b3b3b3;  /* Changed from #999 for WCAG AA compliance (4.5:1 contrast) */
  --color-border: #333;
  --color-link: #6b9eff;
  --color-link-hover: #fff;
}

/* Apply theme colors */
html {
  background-color: var(--color-bg);
}

body {
  background-color: var(--color-bg);
  color: var(--color-text);
  transition: background-color 0.3s ease, color 0.3s ease;
}

a {
  color: var(--color-link);
}

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

.header {
  border-bottom-color: var(--color-border);
}

.footer {
  border-top-color: var(--color-border);
}

/* Theme toggle button styles */
.theme-toggle {
  background: none;
  border: 1px solid var(--color-border);
  border-radius: 4px;
  padding: 0.5rem;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  transition: all 0.3s ease;
  width: 2.5rem;
  height: 2.5rem;
}

.theme-toggle:hover {
  background-color: var(--color-border);
}

.theme-toggle svg {
  width: 1.25rem;
  height: 1.25rem;
  fill: var(--color-text);
}

/* Show/hide icons based on theme */
[data-theme="light"] .moon-icon {
  display: none;
}

[data-theme="dark"] .sun-icon {
  display: none;
}

/* ============================================
   SKIP NAVIGATION LINK
   Accessibility - allows keyboard users to
   bypass repetitive navigation
   ============================================ */

.skip-link {
  /* Visually hidden but accessible to screen readers and keyboard */
  position: absolute;
  left: -9999px;
  width: 1px;
  height: 1px;
  overflow: hidden;

  /* Styling for when it becomes visible */
  background: #000;
  color: #fff;
  padding: 8px 16px;
  text-decoration: none;
  z-index: 100;
}

.skip-link:focus {
  /* Make visible and positioned at top when focused */
  left: 0;
  top: 0;
  width: auto;
  height: auto;
  overflow: visible;
}

/* Dark mode skip-link */
[data-theme="dark"] .skip-link {
  background: #fff;
  color: #000;
}

/* ============================================
   FOCUS INDICATORS
   Critical for keyboard navigation accessibility
   ============================================ */

/* Base focus style - applies to all interactive elements */
a:focus,
button:focus,
input:focus,
textarea:focus,
select:focus {
  /* Visible outline for keyboard users */
  outline: 2px solid var(--color-link);
  outline-offset: 2px;
}

/* Remove outline for mouse users (if browser supports :focus-visible) */
a:focus:not(:focus-visible),
button:focus:not(:focus-visible),
input:focus:not(:focus-visible),
textarea:focus:not(:focus-visible),
select:focus:not(:focus-visible) {
  outline: none;
}

/* Enhanced focus for keyboard users only */
a:focus-visible,
button:focus-visible,
input:focus-visible,
textarea:focus-visible,
select:focus-visible {
  outline: 3px solid var(--color-link);
  outline-offset: 2px;
}