/* 
 * Accessible Jekyll Template CSS
 * WCAG 2.1 Level AA Compliant
 * Title II Requirements Compliant
 */

/* ============================================
   CSS Reset and Base Styles
   ============================================ */

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

/* ============================================
   Root Variables - WCAG AA Compliant Colors
   ============================================ */

:root {
  /* Color Palette with 4.5:1 contrast ratio minimum */
  --color-primary: #0056b3;        /* Dark blue - 7.54:1 contrast on white */
  --color-primary-dark: #003d82;   /* Darker blue for hover */
  --color-secondary: #6c757d;      /* Gray - 4.54:1 contrast on white */
  --color-text: #212529;           /* Dark gray - 15.96:1 contrast on white */
  --color-text-light: #495057;     /* Medium gray - 8.59:1 contrast on white */
  --color-background: #ffffff;     /* White */
  --color-background-alt: #f8f9fa; /* Light gray */
  --color-border: #dee2e6;         /* Border gray */
  --color-border-dark: #ced4da;    /* Darker border - for code elements */
  --color-focus: #0056b3;          /* Focus indicator color */
  --color-error: #721c24;          /* Error text - 9.65:1 contrast */
  --color-success: #155724;        /* Success text - 8.59:1 contrast */
  
  /* Typography */
  --font-family-base: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-family-mono: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, Courier, monospace;
  --font-size-base: 1rem;
  --line-height-base: 1.6;
  
  /* Spacing */
  --spacing-xs: 0.5rem;
  --spacing-sm: 1rem;
  --spacing-md: 1.5rem;
  --spacing-lg: 2rem;
  --spacing-xl: 3rem;
  
  /* Layout */
  --container-max-width: 1200px;
  --content-max-width: 800px;
}

/* ============================================
   Base Typography
   ============================================ */

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

body {
  font-family: var(--font-family-base);
  font-size: var(--font-size-base);
  line-height: var(--line-height-base);
  color: var(--color-text);
  background-color: var(--color-background);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* Ensure proper heading hierarchy */
h1, h2, h3, h4, h5, h6 {
  margin-top: var(--spacing-lg);
  margin-bottom: var(--spacing-sm);
  line-height: 1.3;
  font-weight: 700;
  color: var(--color-text);
}

h1 {
  font-size: 2.5rem;
}

h2 {
  font-size: 2rem;
}

h3 {
  font-size: 1.75rem;
}

h4 {
  font-size: 1.5rem;
}

h5 {
  font-size: 1.25rem;
}

h6 {
  font-size: 1rem;
}

p {
  margin-bottom: var(--spacing-sm);
}

/* ============================================
   Links - WCAG AA Compliant
   ============================================ */

a {
  color: var(--color-primary);
  text-decoration: underline;
  text-decoration-skip-ink: auto;
  transition: color 0.2s ease;
}

a:hover,
a:focus {
  color: var(--color-primary-dark);
  text-decoration: underline;
}

/* Focus styles for keyboard navigation - CRITICAL for accessibility */
a:focus,
button:focus,
input:focus,
textarea:focus,
select:focus {
  outline: 3px solid var(--color-focus);
  outline-offset: 2px;
}

/* Skip link for keyboard users */
.skip-link {
  position: absolute;
  top: -40px;
  left: 0;
  background: var(--color-text);
  color: var(--color-background);
  padding: var(--spacing-xs) var(--spacing-sm);
  text-decoration: none;
  font-weight: 700;
  z-index: 100;
}

.skip-link:focus {
  top: 0;
  outline: 3px solid var(--color-focus);
}

/* ============================================
   Layout Components
   ============================================ */

.container {
  max-width: var(--container-max-width);
  margin: 0 auto;
  padding: 0 var(--spacing-md);
}

/* ============================================
   Header and Navigation
   ============================================ */

.site-header {
  background-color: var(--color-background);
  border-bottom: 2px solid var(--color-border);
  padding: var(--spacing-sm) 0;
  position: sticky;
  top: 0;
  z-index: 10;
}

.site-header nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--spacing-sm);
}

.site-title {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--color-text);
  text-decoration: none;
}

.site-title:hover,
.site-title:focus {
  color: var(--color-primary);
}

.nav-menu {
  display: flex;
  list-style: none;
  gap: var(--spacing-md);
  flex-wrap: wrap;
}

.nav-menu li {
  margin: 0;
}

.nav-menu a {
  color: var(--color-text);
  text-decoration: none;
  font-weight: 500;
  padding: var(--spacing-xs) var(--spacing-sm);
  display: block;
  border-radius: 4px;
  transition: background-color 0.2s ease, color 0.2s ease;
}

.nav-menu a:hover,
.nav-menu a:focus {
  background-color: var(--color-background-alt);
  color: var(--color-primary);
}

.nav-menu a[aria-current="page"] {
  background-color: var(--color-primary);
  color: var(--color-background);
  font-weight: 700;
}

/* ============================================
   Main Content
   ============================================ */

.main-content {
  min-height: 60vh;
  padding: var(--spacing-xl) 0;
}

/* ============================================
   Page and Post Styles
   ============================================ */

.page,
.post {
  max-width: var(--content-max-width);
  margin: 0 auto;
}

.page-header,
.post-header {
  margin-bottom: var(--spacing-lg);
  padding-bottom: var(--spacing-md);
  border-bottom: 2px solid var(--color-border);
}

.post-meta {
  color: var(--color-text-light);
  font-size: 0.9rem;
  margin-top: var(--spacing-sm);
}

.page-content,
.post-content {
  line-height: 1.8;
}

.post-footer {
  margin-top: var(--spacing-lg);
  padding-top: var(--spacing-md);
  border-top: 1px solid var(--color-border);
}

.tag {
  display: inline-block;
  background-color: var(--color-background-alt);
  padding: var(--spacing-xs);
  border-radius: 4px;
  font-size: 0.85rem;
}

/* ============================================
   Lists
   ============================================ */

ul, ol {
  margin-left: var(--spacing-lg);
  margin-bottom: var(--spacing-sm);
}

li {
  margin-bottom: var(--spacing-xs);
}

/* ============================================
   Images - Accessible by Default
   ============================================ */

img {
  max-width: 100%;
  height: auto;
  display: block;
  margin: var(--spacing-md) 0;
}

/* Ensure images have alt text in development */
img:not([alt]) {
  border: 3px solid var(--color-error);
}

figure {
  margin: var(--spacing-lg) 0;
}

figcaption {
  font-size: 0.9rem;
  color: var(--color-text-light);
  font-style: italic;
  margin-top: var(--spacing-xs);
  text-align: center;
}

/* ============================================
   Code Blocks
   ============================================ */

code {
  font-family: var(--font-family-mono);
  font-size: 0.9em;
  background-color: var(--color-border);
  padding: 0.2em 0.4em;
  border-radius: 3px;
  border: 1px solid var(--color-border-dark);
  color: var(--color-text);
}

pre {
  background-color: var(--color-border);
  padding: var(--spacing-sm);
  border-radius: 4px;
  border: 1px solid var(--color-border-dark);
  overflow-x: auto;
  margin: var(--spacing-md) 0;
}

pre code {
  background-color: transparent;
  padding: 0;
}

/* ============================================
   Tables - Accessible Structure
   ============================================ */

table {
  width: 100%;
  border-collapse: collapse;
  margin: var(--spacing-md) 0;
}

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

th {
  background-color: var(--color-background-alt);
  font-weight: 700;
}

/* ============================================
   Forms - Accessible by Default
   ============================================ */

label {
  display: block;
  font-weight: 600;
  margin-bottom: var(--spacing-xs);
  color: var(--color-text);
}

input[type="text"],
input[type="email"],
input[type="url"],
input[type="tel"],
input[type="search"],
textarea,
select {
  width: 100%;
  padding: var(--spacing-xs) var(--spacing-sm);
  border: 2px solid var(--color-border);
  border-radius: 4px;
  font-family: inherit;
  font-size: 1rem;
  line-height: var(--line-height-base);
  background-color: var(--color-background);
  color: var(--color-text);
  transition: border-color 0.2s ease;
}

input:focus,
textarea:focus,
select:focus {
  border-color: var(--color-primary);
  outline: 3px solid var(--color-focus);
  outline-offset: 2px;
}

button,
input[type="submit"],
input[type="button"] {
  background-color: var(--color-primary);
  color: var(--color-background);
  border: none;
  padding: var(--spacing-xs) var(--spacing-md);
  font-size: 1rem;
  font-weight: 600;
  border-radius: 4px;
  cursor: pointer;
  transition: background-color 0.2s ease;
}

button:hover,
button:focus,
input[type="submit"]:hover,
input[type="submit"]:focus {
  background-color: var(--color-primary-dark);
}

/* ============================================
   Footer
   ============================================ */

.site-footer {
  background-color: var(--color-background-alt);
  border-top: 2px solid var(--color-border);
  padding: var(--spacing-lg) 0;
  margin-top: var(--spacing-xl);
  text-align: center;
}

.site-footer p {
  margin-bottom: var(--spacing-sm);
  color: var(--color-text-light);
}

/* ============================================
   Blog List
   ============================================ */

.post-list {
  list-style: none;
  margin-left: 0;
  margin-top: var(--spacing-lg);
}

.post-list-item {
  margin-bottom: var(--spacing-lg);
  padding-bottom: var(--spacing-lg);
  border-bottom: 1px solid var(--color-border);
}

.post-list-item:last-child {
  border-bottom: none;
}

.post-list-title {
  font-size: 1.75rem;
  margin-top: 0;
  margin-bottom: var(--spacing-xs);
}

.post-list-title a {
  color: var(--color-text);
  text-decoration: none;
}

.post-list-title a:hover,
.post-list-title a:focus {
  color: var(--color-primary);
  text-decoration: underline;
}

/* ============================================
   Responsive Design
   ============================================ */

@media (max-width: 768px) {
  html {
    font-size: 14px;
  }
  
  h1 {
    font-size: 2rem;
  }
  
  h2 {
    font-size: 1.75rem;
  }
  
  h3 {
    font-size: 1.5rem;
  }
  
  .site-header nav {
    flex-direction: column;
    align-items: flex-start;
  }
  
  .nav-menu {
    width: 100%;
    flex-direction: column;
    gap: var(--spacing-xs);
  }
  
  .nav-menu a {
    width: 100%;
  }
}

/* ============================================
   Print Styles
   ============================================ */

@media print {
  .skip-link,
  .site-header,
  .site-footer {
    display: none;
  }
  
  .main-content {
    padding: 0;
  }
  
  a {
    color: var(--color-text);
    text-decoration: none;
  }
  
  a[href^="http"]:after {
    content: " (" attr(href) ")";
  }
}

/* ============================================
   Reduced Motion Support
   ============================================ */

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}

/* ============================================
   High Contrast Mode Support
   ============================================ */

@media (prefers-contrast: high) {
  :root {
    --color-primary: #0000ff;
    --color-text: #000000;
    --color-background: #ffffff;
  }
  
  a {
    text-decoration: underline;
    font-weight: 700;
  }
}