/* ============================================
   CSS Custom Properties (Theme Variables)
   ============================================ */

:root {
  /* Light theme colors */
  --bg-primary: #ffffff;
  --bg-secondary: #f8f9fa;
  --bg-tertiary: #e9ecef;
  --text-primary: #1a1a1a;
  --text-secondary: #4a5568;
  --text-tertiary: #718096;
  --accent: #2563eb;
  --accent-hover: #1d4ed8;
  --border: #e2e8f0;
  --code-bg: #f7fafc;
  --shadow: rgba(0, 0, 0, 0.1);

  /* Typography */
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', 'Courier New', monospace;

  /* Spacing */
  --space-xs: 0.5rem;
  --space-sm: 1rem;
  --space-md: 1.5rem;
  --space-lg: 2rem;
  --space-xl: 3rem;
  --space-2xl: 4rem;

  /* Layout */
  --max-width: 800px;
  --border-radius: 8px;

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

/* Dark theme colors */
[data-theme="dark"] {
  --bg-primary: #0f172a;
  --bg-secondary: #1e293b;
  --bg-tertiary: #334155;
  --text-primary: #f1f5f9;
  --text-secondary: #cbd5e1;
  --text-tertiary: #94a3b8;
  --accent: #3b82f6;
  --accent-hover: #60a5fa;
  --border: #334155;
  --code-bg: #1e293b;
  --shadow: rgba(0, 0, 0, 0.3);
}

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

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
  /* Prevent layout shift from scrollbar appearing/disappearing */
  overflow-y: scroll;
}

body {
  font-family: var(--font-sans);
  font-size: 1rem;
  line-height: 1.7;
  color: var(--text-primary);
  background-color: var(--bg-primary);
  transition: background-color var(--transition-normal), color var(--transition-normal);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

.container {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.site-content {
  flex: 1;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: var(--space-xl) var(--space-md);
  width: 100%;
}

/* ============================================
   Header
   ============================================ */

.site-header {
  border-bottom: 1px solid var(--border);
  background-color: var(--bg-primary);
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(10px);
  transition: border-color var(--transition-normal);
}

.header-content {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: var(--space-md);
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: var(--space-md);
}

.site-title {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-primary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

.site-title:hover {
  color: var(--accent);
}

.site-nav {
  display: flex;
  align-items: center;
  gap: var(--space-md);
}

.site-nav a {
  color: var(--text-secondary);
  text-decoration: none;
  font-weight: 500;
  font-size: 0.9375rem;
  transition: color var(--transition-fast);
  padding: var(--space-xs) 0;
  position: relative;
}

.site-nav a:hover {
  color: var(--text-primary);
}

.site-nav a.active {
  color: var(--accent);
}

.site-nav a.active::after {
  content: '';
  position: absolute;
  bottom: -1px;
  left: 0;
  right: 0;
  height: 2px;
  background-color: var(--accent);
}

/* Theme toggle button */
.theme-toggle {
  background: transparent;
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 0.5rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition-fast);
  color: var(--text-secondary);
}

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

.theme-toggle svg {
  display: block;
  width: 20px;
  height: 20px;
}

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

[data-theme="light"] .sun-icon,
[data-theme="dark"] .moon-icon {
  display: block;
}

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

h1, h2, h3, h4, h5, h6 {
  font-weight: 700;
  line-height: 1.3;
  color: var(--text-primary);
  margin-top: var(--space-lg);
  margin-bottom: var(--space-sm);
}

h1 {
  font-size: 2.5rem;
  margin-top: 0;
  letter-spacing: -0.02em;
}

h2 {
  font-size: 1.875rem;
  margin-top: var(--space-2xl);
  letter-spacing: -0.01em;
}

h3 {
  font-size: 1.5rem;
  color: var(--text-primary);
}

h4 {
  font-size: 1.25rem;
  color: var(--text-primary);
}

p {
  margin-bottom: var(--space-md);
  color: var(--text-secondary);
}

a {
  color: var(--accent);
  text-decoration: none;
  transition: color var(--transition-fast);
}

a:hover {
  color: var(--accent-hover);
  text-decoration: underline;
}

strong {
  font-weight: 600;
  color: var(--text-primary);
}

em {
  font-style: italic;
}

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

ul, ol {
  margin-bottom: var(--space-md);
  padding-left: var(--space-lg);
}

li {
  margin-bottom: var(--space-xs);
  color: var(--text-secondary);
}

li::marker {
  color: var(--accent);
}

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

code {
  font-family: var(--font-mono);
  font-size: 0.875em;
  background-color: var(--code-bg);
  padding: 0.2em 0.4em;
  border-radius: 4px;
  color: var(--text-primary);
  border: 1px solid var(--border);
}

pre {
  background-color: var(--code-bg);
  border: 1px solid var(--border);
  border-radius: var(--border-radius);
  padding: var(--space-md);
  margin-bottom: var(--space-md);
  overflow-x: auto;
  line-height: 1.5;
}

pre code {
  background: transparent;
  padding: 0;
  border: none;
  font-size: 0.875rem;
}

/* ============================================
   Blockquotes
   ============================================ */

blockquote {
  border-left: 4px solid var(--accent);
  padding-left: var(--space-md);
  margin: var(--space-lg) 0;
  color: var(--text-secondary);
  font-style: italic;
}

/* ============================================
   Horizontal Rules
   ============================================ */

hr {
  border: none;
  border-top: 1px solid var(--border);
  margin: var(--space-2xl) 0;
}

/* ============================================
   Images
   ============================================ */

img {
  max-width: 100%;
  height: auto;
  border-radius: var(--border-radius);
  margin: var(--space-md) 0;
}

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

.site-footer {
  border-top: 1px solid var(--border);
  background-color: var(--bg-secondary);
  margin-top: var(--space-2xl);
}

.footer-content {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: var(--space-lg) var(--space-md);
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--space-md);
}

.footer-content p {
  margin: 0;
  color: var(--text-tertiary);
  font-size: 0.875rem;
}

.social-links {
  display: flex;
  gap: var(--space-md);
}

.social-links a {
  color: var(--text-tertiary);
  font-size: 0.875rem;
  font-weight: 500;
  text-decoration: none;
  transition: color var(--transition-fast);
}

.social-links a:hover {
  color: var(--accent);
  text-decoration: none;
}

/* ============================================
   Project Cards (for projects page)
   ============================================ */

.project-card {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--border-radius);
  padding: var(--space-lg);
  margin-bottom: var(--space-xl);
  transition: all var(--transition-normal);
}

.project-card:hover {
  border-color: var(--accent);
  box-shadow: 0 4px 12px var(--shadow);
  transform: translateY(-2px);
}

.project-card h2 {
  margin-top: 0;
}

.project-meta {
  display: flex;
  gap: var(--space-md);
  margin-bottom: var(--space-md);
  flex-wrap: wrap;
}

.project-badge {
  display: inline-block;
  padding: 0.25rem 0.75rem;
  background-color: var(--bg-tertiary);
  border-radius: 12px;
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--text-primary);
}

/* ============================================
   Status badges
   ============================================ */

.status-badge {
  display: inline-block;
  padding: 0.25rem 0.75rem;
  border-radius: 12px;
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.status-active {
  background-color: #10b98120;
  color: #059669;
}

.status-planning {
  background-color: #3b82f620;
  color: #2563eb;
}

.status-complete {
  background-color: #8b5cf620;
  color: #7c3aed;
}

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

@media (max-width: 768px) {
  html {
    font-size: 15px;
  }

  h1 {
    font-size: 2rem;
  }

  h2 {
    font-size: 1.5rem;
  }

  h3 {
    font-size: 1.25rem;
  }

  .header-content {
    flex-direction: column;
    align-items: flex-start;
  }

  .site-nav {
    width: 100%;
    justify-content: space-between;
  }

  .site-content {
    padding: var(--space-lg) var(--space-md);
  }

  .footer-content {
    flex-direction: column;
    align-items: flex-start;
    text-align: left;
  }
}

@media (max-width: 480px) {
  .site-nav {
    font-size: 0.875rem;
    gap: var(--space-sm);
  }

  .site-nav a {
    padding: var(--space-xs);
  }
}

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

@media print {
  .site-header,
  .site-footer,
  .theme-toggle {
    display: none;
  }

  body {
    color: #000;
    background: #fff;
  }

  a {
    text-decoration: underline;
    color: #000;
  }

  a[href^="http"]:after {
    content: " (" attr(href) ")";
    font-size: 0.8em;
  }
}

/* ============================================
   Utility Classes
   ============================================ */

.text-center {
  text-align: center;
}

.mt-0 { margin-top: 0; }
.mb-0 { margin-bottom: 0; }
.mt-sm { margin-top: var(--space-sm); }
.mb-sm { margin-bottom: var(--space-sm); }
.mt-md { margin-top: var(--space-md); }
.mb-md { margin-bottom: var(--space-md); }
.mt-lg { margin-top: var(--space-lg); }
.mb-lg { margin-bottom: var(--space-lg); }