/* ============================================================================
   Accessibility Add-On Layer
   WCAG AAA & UDL Compliance Enhancements
   ============================================================================ */

:root {
  /* Dark mode color scheme - WCAG AAA compliant (all 7:1+) */
  --background: #0d1117;
  --foreground: #ffffff;
  --a11y-accent: #58a6ff;
  --a11y-accent-hover: #79c0ff;
  --a11y-accent-visited: #bc8ef8;
  --a11y-success: #3fb950;
  --a11y-error: #ff8888;
  --a11y-warning: #d29922;
  --a11y-focus-color: #ffffff;
  --a11y-focus-outline: #58a6ff;
  --a11y-focus-bg: #0d1117;
}

/* Skip to main content link - hidden by default, visible on focus */
.skip-to-main {
  position: absolute;
  top: -40px;
  left: 0;
  background: var(--a11y-focus-bg);
  color: var(--a11y-focus-color);
  padding: 8px 16px;
  text-decoration: none;
  z-index: 100;
  border-bottom: 2px solid var(--a11y-focus-color);
  font-weight: bold;
}

.skip-to-main:focus {
  top: 0;
  outline: 3px solid var(--a11y-focus-color);
  outline-offset: 2px;
}

/* Enhanced focus visible styles for AAA compliance */
a:focus-visible,
button:focus-visible,
input:focus-visible,
textarea:focus-visible,
select:focus-visible {
  outline: 3px solid var(--a11y-focus-color) !important;
  outline-offset: 2px;
}

/* Keyboard focus indicator for interactive elements */
*:focus-visible {
  outline: 3px solid var(--a11y-focus-color);
  outline-offset: 2px;
}

/* Enhanced visibility for navigation links */
.navigation-menu__inner a:focus-visible {
  outline: 3px solid #ffff00;
  outline-offset: 2px;
  box-shadow: 0 0 0 2px rgba(255, 255, 0, 0.4);
}

/* Enhanced heading contrast and hierarchy */
h1, h2, h3, h4, h5, h6 {
  color: var(--foreground);
  margin-bottom: 0.5em;
  margin-top: 0.75em;
}

h1 {
  font-size: 2.2em;
  font-weight: 700;
  letter-spacing: -0.02em;
}

h2 {
  font-size: 1.8em;
  font-weight: 700;
  letter-spacing: -0.01em;
}

h3 {
  font-size: 1.4em;
  font-weight: 600;
}

h4 {
  font-size: 1.2em;
  font-weight: 600;
}

h5, h6 {
  font-size: 1em;
  font-weight: 600;
}

/* Link contrast enhancement - AAA compliant bright colors */
a {
  color: var(--a11y-accent);
  text-decoration: underline;
  text-decoration-thickness: 2px;
  text-underline-offset: 3px;
  transition: color 0.15s linear;
}

a:hover {
  color: var(--a11y-accent-hover);
  text-decoration-thickness: 3px;
}

a:visited {
  color: var(--a11y-accent-visited);
}

/* Form accessibility improvements */
label {
  display: block;
  margin-bottom: 0.5em;
  font-weight: 500;
  color: var(--foreground);
}

label input[type="checkbox"],
label input[type="radio"] {
  margin-right: 0.5em;
  margin-top: 0;
  width: auto;
}

input[type="text"],
input[type="email"],
input[type="password"],
input[type="search"],
input[type="url"],
textarea,
select {
  min-height: 44px; /* WCAG touch target size */
  font-size: 16px; /* Prevents zoom on focus on iOS */
  border: 2px solid var(--foreground);
}

input:focus-visible,
textarea:focus-visible,
select:focus-visible {
  border-color: var(--a11y-focus-color);
  background-color: rgba(255, 255, 255, 0.05);
}

/* Error messages - AAA compliant red */
.form-error,
[aria-invalid="true"],
.error {
  color: var(--a11y-error);
  background-color: rgba(248, 81, 73, 0.15);
  padding: 0.5em;
  border-left: 4px solid var(--a11y-error);
  margin: 0.5em 0;
  font-weight: 500;
}

/* Success messages - AAA compliant green */
.form-success,
.success {
  color: var(--a11y-success);
  background-color: rgba(63, 185, 80, 0.15);
  padding: 0.5em;
  border-left: 4px solid var(--a11y-success);
  margin: 0.5em 0;
  font-weight: 500;
}

/* Ensure sufficient line height for readability */
body {
  line-height: 1.6;
}

p, li, dt, dd {
  line-height: 1.6;
}

/* Code blocks - AAA compliant cyan text */
code,
pre {
  background-color: rgba(88, 166, 255, 0.1);
  color: var(--a11y-accent);
  border-radius: 4px;
  padding: 2px 6px;
}

pre {
  padding: 1em;
  overflow-x: auto;
  border: 1px solid var(--foreground);
}

/* Alt text for images that are missing */
img:not([alt]),
img[alt=""] {
  border: 3px dashed #ff6b6b;
  background-color: rgba(255, 107, 107, 0.1);
}

/* Reduce motion for users who prefer it */
@media (prefers-reduced-motion: reduce) {
  * {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}

/* Dark mode support - respects prefers-color-scheme */
@media (prefers-color-scheme: light) {
  :root {
    --a11y-focus-color: #000000;
    --a11y-focus-bg: #ffffff;
  }
}

/* High contrast mode support */
@media (prefers-contrast: more) {
  a {
    text-decoration-thickness: 3px;
  }

  button,
  input,
  textarea,
  select {
    border-width: 2px;
  }
}

/* Print styles for accessibility */
@media print {
  a {
    text-decoration: underline;
  }

  a::after {
    content: " (" attr(href) ")";
  }

  .skip-to-main {
    display: none;
  }
}

/* Visually hide content but keep it available to screen readers */
.sr-only,
.a11y-sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border-width: 0;
}

/* Visible focus indicator for keyboard navigation */
.keyboard-focus:focus-visible {
  outline: 3px dashed var(--a11y-focus-color);
  outline-offset: 3px;
}

/* Wider container for full navigation visibility */
.container {
  max-width: 1200px;
}

/* Navigation menu - compact spacing so items fit */
.navigation-menu__inner > li:not(:last-of-type) {
  margin-right: 15px;
}