/* ==========================================================================
   CSS Custom Properties for Theming System
   ========================================================================== */

/* Base theme variables - Light theme (default) */
:root {
  /* Color palette */
  --color-bg: #ffffff;
  --color-text: #333333;
  --color-text-secondary: #666666;
  --color-card-bg: #f8f9fa;
  --color-card-border: #e9ecef;
  --color-accent: #007bff;
  --color-accent-hover: #0056b3;
  --color-focus: #0056b3;
  
  /* Status colors */
  --color-status-planning: #6c757d;
  --color-status-progress: #ffc107;
  --color-status-active: #28a745;
  --color-status-done: #17a2b8;
  
  /* Interactive states */
  --color-link: #007bff;
  --color-link-hover: #0056b3;
  --color-link-visited: #6f42c1;
  
  /* Shadows and borders */
  --shadow-card: 0 2px 4px rgba(0, 0, 0, 0.1);
  --shadow-card-hover: 0 4px 8px rgba(0, 0, 0, 0.15);
  --border-radius: 8px;
  --border-width: 1px;
  
  /* Typography */
  --font-family-base: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  --font-size-base: 1rem;
  --font-size-small: 0.875rem;
  --font-size-large: 1.125rem;
  --font-size-xl: 1.25rem;
  --font-size-xxl: 1.5rem;
  --line-height-base: 1.5;
  --line-height-tight: 1.25;
  
  /* Spacing */
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2rem;
  --spacing-xxl: 3rem;
}

/* Dark theme */
[data-theme="dark"] {
  --color-bg: #1a1a1a;
  --color-text: #ffffff;
  --color-text-secondary: #cccccc;
  --color-card-bg: #2d2d2d;
  --color-card-border: #404040;
  --color-accent: #4dabf7;
  --color-accent-hover: #339af0;
  --color-focus: #339af0;
  
  /* Status colors - adjusted for dark theme */
  --color-status-planning: #868e96;
  --color-status-progress: #ffd43b;
  --color-status-active: #51cf66;
  --color-status-done: #22b8cf;
  
  /* Interactive states */
  --color-link: #4dabf7;
  --color-link-hover: #339af0;
  --color-link-visited: #9775fa;
  
  /* Shadows and borders */
  --shadow-card: 0 2px 4px rgba(0, 0, 0, 0.3);
  --shadow-card-hover: 0 4px 8px rgba(0, 0, 0, 0.4);
}

/* High contrast theme */
[data-theme="high-contrast"] {
  --color-bg: #000000;
  --color-text: #ffffff;
  --color-text-secondary: #ffffff;
  --color-card-bg: #000000;
  --color-card-border: #ffffff;
  --color-accent: #ffff00;
  --color-accent-hover: #ffff99;
  --color-focus: #ffff00;
  
  /* Status colors - high contrast */
  --color-status-planning: #ffffff;
  --color-status-progress: #ffff00;
  --color-status-active: #00ff00;
  --color-status-done: #00ffff;
  
  /* Interactive states */
  --color-link: #ffff00;
  --color-link-hover: #ffff99;
  --color-link-visited: #ff00ff;
  
  /* Shadows and borders - more prominent for high contrast */
  --shadow-card: 0 2px 4px rgba(255, 255, 255, 0.3);
  --shadow-card-hover: 0 4px 8px rgba(255, 255, 255, 0.5);
  --border-width: 2px;
}

/* CSS-only theme switching using prefers-color-scheme */
@media (prefers-color-scheme: dark) {
  :root:not([data-theme]) {
    --color-bg: #1a1a1a;
    --color-text: #ffffff;
    --color-text-secondary: #cccccc;
    --color-card-bg: #2d2d2d;
    --color-card-border: #404040;
    --color-accent: #4dabf7;
    --color-accent-hover: #339af0;
    --color-focus: #339af0;
    
    --color-status-planning: #868e96;
    --color-status-progress: #ffd43b;
    --color-status-active: #51cf66;
    --color-status-done: #22b8cf;
    
    --color-link: #4dabf7;
    --color-link-hover: #339af0;
    --color-link-visited: #9775fa;
    
    --shadow-card: 0 2px 4px rgba(0, 0, 0, 0.3);
    --shadow-card-hover: 0 4px 8px rgba(0, 0, 0, 0.4);
  }
}

/* Respect user's motion preferences */
@media (prefers-reduced-motion: reduce) {
  :root {
    --transition-duration: 0s;
  }
}

@media (prefers-reduced-motion: no-preference) {
  :root {
    --transition-duration: 0.2s;
  }
}

/* ==========================================================================
   Base Styles
   ========================================================================== */

/* Reset and base styles */
*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  font-size: 100%;
  scroll-behavior: smooth;
}

body {
  margin: 0;
  padding: 0;
  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-bg);
  transition: background-color var(--transition-duration) ease,
              color var(--transition-duration) ease;
}

/* Accessibility utilities */
.visually-hidden {
  position: absolute !important;
  width: 1px !important;
  height: 1px !important;
  padding: 0 !important;
  margin: -1px !important;
  overflow: hidden !important;
  clip: rect(0, 0, 0, 0) !important;
  white-space: nowrap !important;
  border: 0 !important;
}

.skip-link {
  position: absolute;
  top: -40px;
  left: 6px;
  background: var(--color-accent);
  color: var(--color-bg);
  padding: var(--spacing-sm) var(--spacing-md);
  text-decoration: none;
  border-radius: var(--border-radius);
  z-index: 1000;
  transition: top var(--transition-duration) ease;
}

.skip-link:focus {
  top: 6px;
}

/* Focus styles for accessibility */
:focus {
  outline: 2px solid var(--color-focus);
  outline-offset: 2px;
}

:focus:not(:focus-visible) {
  outline: none;
}

:focus-visible {
  outline: 2px solid var(--color-focus);
  outline-offset: 2px;
}

/* Enhanced focus styles for interactive elements */
.project-card:focus-within {
  box-shadow: var(--shadow-card-hover), 0 0 0 2px var(--color-focus);
}

.card-link:focus {
  outline: 2px solid var(--color-focus);
  outline-offset: 2px;
  border-radius: 2px;
}

.social-links a:focus {
  outline: 2px solid var(--color-focus);
  outline-offset: 2px;
}

/* ARIA live region for screen reader announcements */
#aria-live-region {
  position: absolute !important;
  width: 1px !important;
  height: 1px !important;
  padding: 0 !important;
  margin: -1px !important;
  overflow: hidden !important;
  clip: rect(0, 0, 0, 0) !important;
  white-space: nowrap !important;
  border: 0 !important;
}

/* Portfolio status indicator */
.portfolio-status {
  position: absolute !important;
  width: 1px !important;
  height: 1px !important;
  padding: 0 !important;
  margin: -1px !important;
  overflow: hidden !important;
  clip: rect(0, 0, 0, 0) !important;
  white-space: nowrap !important;
  border: 0 !important;
}
/* =
=========================================================================
   Layout - Header and Navigation
   ========================================================================== */

.site-header {
  background-color: var(--color-card-bg);
  border-bottom: var(--border-width) solid var(--color-card-border);
  padding: var(--spacing-lg) var(--spacing-md);
  margin-bottom: var(--spacing-xl);
  transition: background-color var(--transition-duration) ease,
              border-color var(--transition-duration) ease;
}

.site-header h1 {
  margin: 0 0 var(--spacing-md) 0;
  font-size: var(--font-size-xxl);
  font-weight: 700;
  line-height: var(--line-height-tight);
  color: var(--color-text);
}

/* Theme switcher navigation */
.theme-switcher {
  margin-top: var(--spacing-md);
}

.theme-switcher fieldset {
  border: none;
  margin: 0;
  padding: 0;
  display: flex;
  gap: var(--spacing-md);
  flex-wrap: wrap;
}

.theme-switcher label {
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
  cursor: pointer;
  padding: var(--spacing-sm) var(--spacing-md);
  border: var(--border-width) solid var(--color-card-border);
  border-radius: var(--border-radius);
  background-color: var(--color-bg);
  color: var(--color-text);
  transition: all var(--transition-duration) ease;
  font-size: var(--font-size-small);
}

.theme-switcher label:hover {
  background-color: var(--color-card-bg);
  border-color: var(--color-accent);
}

.theme-switcher input[type="radio"] {
  margin: 0;
  width: 1rem;
  height: 1rem;
}

.theme-switcher input[type="radio"]:checked + span {
  font-weight: 600;
}

.theme-switcher label:has(input:checked) {
  background-color: var(--color-accent);
  color: var(--color-bg);
  border-color: var(--color-accent);
}

/* ==========================================================================
   Responsive Grid Layout for Project Cards
   ========================================================================== */

.portfolio-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: var(--spacing-xl);
  padding: 0 var(--spacing-md);
  max-width: 1200px;
  margin: 0 auto var(--spacing-xxl) auto;
}

/* Mobile-first responsive breakpoints */

/* Small mobile devices (320px and up) */
@media (max-width: 480px) {
  .portfolio-grid {
    grid-template-columns: 1fr;
    gap: var(--spacing-lg);
    padding: 0 var(--spacing-sm);
  }
  
  .site-header {
    padding: var(--spacing-md) var(--spacing-sm);
  }
  
  .site-header h1 {
    font-size: var(--font-size-xl);
  }
  
  .theme-switcher fieldset {
    gap: var(--spacing-sm);
  }
  
  .theme-switcher label {
    padding: var(--spacing-xs) var(--spacing-sm);
    font-size: 0.75rem;
  }
}

/* Large mobile devices (481px to 768px) */
@media (min-width: 481px) and (max-width: 768px) {
  .portfolio-grid {
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-lg);
  }
}

/* Tablet devices (769px to 1024px) */
@media (min-width: 769px) and (max-width: 1024px) {
  .portfolio-grid {
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: var(--spacing-xl);
    padding: 0 var(--spacing-lg);
  }
  
  .site-header {
    padding: var(--spacing-lg);
  }
}

/* Desktop devices (1025px and up) */
@media (min-width: 1025px) {
  .portfolio-grid {
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: var(--spacing-xl);
    padding: 0 var(--spacing-xl);
  }
  
  .site-header {
    padding: var(--spacing-xl);
    display: flex;
    justify-content: space-between;
    align-items: center;
  }
  
  .site-header h1 {
    margin-bottom: 0;
  }
  
  .theme-switcher {
    margin-top: 0;
  }
}

/* Large desktop devices (1440px and up) */
@media (min-width: 1440px) {
  .portfolio-grid {
    max-width: 1400px;
    grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
  }
}

/* Ultra-wide displays (1920px and up) */
@media (min-width: 1920px) {
  .portfolio-grid {
    max-width: 1600px;
    grid-template-columns: repeat(auto-fit, minmax(450px, 1fr));
  }
}

/* Ensure grid items don't get too wide on very large screens */
.portfolio-grid > * {
  max-width: 500px;
  justify-self: center;
}

@media (min-width: 1025px) {
  .portfolio-grid > * {
    justify-self: stretch;
  }
}

/* Grid layout adjustments for different content amounts */
.portfolio-grid:has(.project-card:nth-child(1):nth-last-child(1)) {
  /* Single item - center it */
  justify-content: center;
}

.portfolio-grid:has(.project-card:nth-child(2):nth-last-child(1)) {
  /* Two items - ensure they don't get too wide */
  grid-template-columns: repeat(2, minmax(300px, 450px));
  justify-content: center;
}

@media (max-width: 768px) {
  .portfolio-grid:has(.project-card:nth-child(2):nth-last-child(1)) {
    grid-template-columns: 1fr;
  }
}/*
 ==========================================================================
   Project Card Components
   ========================================================================== */

.project-card {
  background-color: var(--color-card-bg);
  border: var(--border-width) solid var(--color-card-border);
  border-radius: var(--border-radius);
  box-shadow: var(--shadow-card);
  overflow: hidden;
  transition: all var(--transition-duration) ease;
  display: flex;
  flex-direction: column;
  height: 100%;
}

.project-card:hover {
  box-shadow: var(--shadow-card-hover);
  transform: translateY(-2px);
}

@media (prefers-reduced-motion: reduce) {
  .project-card:hover {
    transform: none;
  }
}

/* Card image section */
.card-image {
  position: relative;
  overflow: hidden;
  aspect-ratio: 3 / 2;
  background-color: var(--color-card-border);
  background-image: linear-gradient(45deg, transparent 25%, rgba(255,255,255,0.1) 25%, rgba(255,255,255,0.1) 50%, transparent 50%, transparent 75%, rgba(255,255,255,0.1) 75%);
  background-size: 20px 20px;
}

.card-image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center;
  transition: transform var(--transition-duration) ease, opacity var(--transition-duration) ease;
}

/* Image loading states */
.card-image img[loading="lazy"] {
  opacity: 0;
}

.card-image img[loading="lazy"].loaded,
.card-image img:not([loading="lazy"]) {
  opacity: 1;
}

/* Image error state */
.card-image img.image-error {
  opacity: 0.7;
  filter: grayscale(100%);
}

/* Skeleton loading animation */
@keyframes skeleton-loading {
  0% {
    background-position: -200px 0;
  }
  100% {
    background-position: calc(200px + 100%) 0;
  }
}

.card-image::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(255,255,255,0.2), transparent);
  background-size: 200px 100%;
  animation: skeleton-loading 1.5s infinite;
  z-index: 1;
  opacity: 0;
  transition: opacity var(--transition-duration) ease;
}

.card-image:has(img[loading="lazy"]:not(.loaded))::before {
  opacity: 1;
}

/* Hide skeleton when image is loaded */
.card-image:has(img.loaded)::before,
.card-image:has(img:not([loading="lazy"]))::before {
  opacity: 0;
}

.project-card:hover .card-image img {
  transform: scale(1.05);
}

@media (prefers-reduced-motion: reduce) {
  .project-card:hover .card-image img {
    transform: none;
  }
}

/* Card content section */
.card-content {
  padding: var(--spacing-lg);
  display: flex;
  flex-direction: column;
  flex-grow: 1;
}

/* Card header */
.card-header {
  margin-bottom: var(--spacing-md);
}

.card-title {
  margin: 0 0 var(--spacing-xs) 0;
  font-size: var(--font-size-xl);
  font-weight: 600;
  line-height: var(--line-height-tight);
}

.card-link {
  color: var(--color-text);
  text-decoration: none;
  transition: color var(--transition-duration) ease;
}

.card-link:hover,
.card-link:focus {
  color: var(--color-accent);
  text-decoration: underline;
}

.card-link:visited {
  color: var(--color-text);
}

.card-link:visited:hover,
.card-link:visited:focus {
  color: var(--color-accent);
}

.card-subtitle {
  margin: 0 0 var(--spacing-sm) 0;
  font-size: var(--font-size-small);
  color: var(--color-text-secondary);
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

/* Status indicators */
.card-status {
  display: inline-block;
  padding: var(--spacing-xs) var(--spacing-sm);
  border-radius: calc(var(--border-radius) / 2);
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  border: var(--border-width) solid transparent;
}

/* Status color variations */
.project-card[data-status="planning"] .card-status {
  background-color: var(--color-status-planning);
  color: var(--color-bg);
  border-color: var(--color-status-planning);
}

.project-card[data-status="in-progress"] .card-status {
  background-color: var(--color-status-progress);
  color: var(--color-bg);
  border-color: var(--color-status-progress);
}

.project-card[data-status="active"] .card-status {
  background-color: var(--color-status-active);
  color: var(--color-bg);
  border-color: var(--color-status-active);
}

.project-card[data-status="done"] .card-status {
  background-color: var(--color-status-done);
  color: var(--color-bg);
  border-color: var(--color-status-done);
}

/* High contrast theme adjustments for status indicators */
[data-theme="high-contrast"] .card-status {
  border-width: 2px;
  font-weight: 700;
}

/* Card description */
.card-description {
  margin: 0 0 var(--spacing-lg) 0;
  color: var(--color-text-secondary);
  line-height: var(--line-height-base);
  flex-grow: 1;
}

/* Card footer with social links */
.card-social {
  margin-top: auto;
  padding-top: var(--spacing-md);
  border-top: var(--border-width) solid var(--color-card-border);
}

.card-social h4 {
  margin: 0;
}

.social-links {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  gap: var(--spacing-sm);
  flex-wrap: wrap;
}

.social-links li {
  margin: 0;
}

.social-links a {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-xs);
  padding: var(--spacing-xs) var(--spacing-sm);
  background-color: var(--color-bg);
  color: var(--color-text-secondary);
  text-decoration: none;
  border: var(--border-width) solid var(--color-card-border);
  border-radius: calc(var(--border-radius) / 2);
  font-size: var(--font-size-small);
  font-weight: 500;
  transition: all var(--transition-duration) ease;
}

.social-links a:hover,
.social-links a:focus {
  background-color: var(--color-accent);
  color: var(--color-bg);
  border-color: var(--color-accent);
  text-decoration: none;
}

.social-links a:visited {
  color: var(--color-text-secondary);
}

.social-links a:visited:hover,
.social-links a:visited:focus {
  background-color: var(--color-accent);
  color: var(--color-bg);
  border-color: var(--color-accent);
}

/* Emoji/icon spacing in social links */
.social-links a span[aria-hidden="true"] {
  font-size: 1em;
  line-height: 1;
}

/* Mobile adjustments for social links */
@media (max-width: 480px) {
  .social-links {
    gap: var(--spacing-xs);
  }
  
  .social-links a {
    padding: var(--spacing-xs);
    font-size: 0.75rem;
  }
}

/* ==========================================================================
   Typography and Content Enhancements
   ========================================================================== */

/* Improved typography hierarchy */
h1, h2, h3, h4, h5, h6 {
  margin-top: 0;
  margin-bottom: var(--spacing-md);
  font-weight: 600;
  line-height: var(--line-height-tight);
  color: var(--color-text);
}

h1 {
  font-size: var(--font-size-xxl);
}

h2 {
  font-size: var(--font-size-xl);
}

h3 {
  font-size: var(--font-size-large);
}

/* Link styles */
a {
  color: var(--color-link);
  transition: color var(--transition-duration) ease;
}

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

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

/* Ensure sufficient color contrast for WCAG compliance */
@media (prefers-contrast: high) {
  :root {
    --color-text: #000000;
    --color-bg: #ffffff;
    --color-text-secondary: #000000;
    --border-width: 2px;
  }
  
  [data-theme="dark"] {
    --color-text: #ffffff;
    --color-bg: #000000;
    --color-text-secondary: #ffffff;
  }
}

/* Image optimization for different formats */
.webp-supported .card-image img[src$=".jpg"],
.webp-supported .card-image img[src$=".png"] {
  /* WebP images would be served here via server-side logic */
}

.avif-supported .card-image img[src$=".jpg"],
.avif-supported .card-image img[src$=".png"] {
  /* AVIF images would be served here via server-side logic */
}

/* Reduced motion preferences */
@media (prefers-reduced-motion: reduce) {
  .card-image::before {
    animation: none;
  }
  
  .card-image img {
    transition: none;
  }
}

/* High contrast mode adjustments */
@media (prefers-contrast: high) {
  .card-image {
    border: 2px solid var(--color-text);
  }
  
  .card-image img.image-error {
    filter: contrast(200%) grayscale(100%);
  }
}

/* Print styles */
@media print {
  .theme-switcher,
  .skip-link,
  #aria-live-region,
  .portfolio-status {
    display: none;
  }
  
  .project-card {
    break-inside: avoid;
    box-shadow: none;
    border: 1px solid #000;
  }
  
  .card-image img {
    filter: grayscale(100%);
  }
  
  .card-image::before {
    display: none;
  }
  
  .social-links a {
    color: #000 !important;
    background: transparent !important;
  }
  
  .social-links a::after {
    content: " (" attr(href) ")";
    font-size: 0.8em;
  }
}