:root {
  /* Light Theme */
  --bg-primary: #ffffff;
  --bg-secondary: #f8f9fa;
  --bg-card: #ffffff;
  --text-primary: #111827;
  --text-secondary: #4b5563;
  --accent: #2563eb;
  --accent-hover: #1d4ed8;
  --border: #e5e7eb;
  --shadow: 0 1px 3px rgba(0,0,0,0.1);
  
  /* Syntax Highlighting Base */
  --code-bg: #f3f4f6;
  --code-text: #1f2937;
}

[data-theme="dark"] {
  /* Dark Theme */
  --bg-primary: #111827;
  --bg-secondary: #1f2937;
  --bg-card: #1f2937;
  --text-primary: #f9fafb;
  --text-secondary: #9ca3af;
  --accent: #60a5fa;
  --accent-hover: #3b82f6;
  --border: #374151;
  --shadow: 0 1px 3px rgba(0,0,0,0.3);

  --code-bg: #111827;
  --code-text: #e5e7eb;
}

/* Reset & Base */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: 'Inter', system-ui, -apple-system, sans-serif;
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  transition: background-color 0.3s, color 0.3s;
}

a {
  color: var(--accent);
  text-decoration: none;
  transition: color 0.2s;
}

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

img {
  max-width: 100%;
  height: auto;
  border-radius: 8px;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
  color: var(--text-primary);
  line-height: 1.2;
  margin-bottom: 1rem;
}

h1 { font-size: 2.5rem; font-weight: 800; letter-spacing: -0.025em; }
h2 { font-size: 2rem; font-weight: 700; margin-top: 2rem; }
h3 { font-size: 1.5rem; font-weight: 600; }

p { margin-bottom: 1.5rem; }

/* Layout */
.container {
  width: 100%;
  max-width: 800px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* Header & Nav */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background-color: rgba(255, 255, 255, 0.8);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  padding: 1rem 0;
}

[data-theme="dark"] .site-header {
  background-color: rgba(17, 24, 39, 0.8);
}

.nav-container {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

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

.nav-links {
  display: flex;
  gap: 1.5rem;
  list-style: none;
}

.nav-links a {
  color: var(--text-secondary);
  font-weight: 500;
  text-decoration: none;
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--accent);
}

.theme-toggle {
  background: none;
  border: 1px solid var(--border);
  color: var(--text-primary);
  padding: 0.5rem;
  border-radius: 50%;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  transition: all 0.2s;
}

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

/* Mobile Menu */
.menu-toggle {
  display: none;
  background: none;
  border: none;
  color: var(--text-primary);
  font-size: 1.5rem;
  cursor: pointer;
}

/* Hero Section */
.hero {
  padding: 4rem 0;
  text-align: center;
  background-color: var(--bg-secondary);
  border-bottom: 1px solid var(--border);
  margin-bottom: 3rem;
}

.hero h1 { margin-bottom: 0.5rem; }
.hero .subtitle {
  color: var(--text-secondary);
  font-size: 1.25rem;
}

/* Cards */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 2rem;
  margin-bottom: 4rem;
}

.post-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 1.5rem;
  transition: transform 0.2s, box-shadow 0.2s;
  display: flex;
  flex-direction: column;
}

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

.post-card h3 {
  margin-top: 0;
  margin-bottom: 0.5rem;
  font-size: 1.25rem;
}

.post-card h3 a {
  color: var(--text-primary);
  text-decoration: none;
}

.post-card .subtitle {
  color: var(--text-secondary);
  font-size: 0.95rem;
  margin-bottom: 1rem;
  flex-grow: 1;
}

.post-meta {
  font-size: 0.85rem;
  color: var(--text-secondary);
  margin-top: auto;
  border-top: 1px solid var(--border);
  padding-top: 1rem;
}

/* Footer */
.site-footer {
  margin-top: auto;
  padding: 3rem 0;
  border-top: 1px solid var(--border);
  text-align: center;
  color: var(--text-secondary);
  background-color: var(--bg-secondary);
}

.social-links {
  margin-bottom: 1rem;
}

.social-links a {
  margin: 0 0.5rem;
  color: var(--text-secondary);
  font-size: 1.5rem;
}

.social-links a:hover {
  color: var(--accent);
}

/* Buttons */
.btn {
  display: inline-block;
  padding: 0.75rem 1.5rem;
  border-radius: 6px;
  font-weight: 600;
  text-decoration: none;
  text-align: center;
  cursor: pointer;
  transition: all 0.2s;
}

.btn-primary {
  background-color: var(--accent);
  color: white;
  border: none;
}

.btn-primary:hover {
  background-color: var(--accent-hover);
  color: white;
  text-decoration: none;
}

/* Alerts */
.alert {
  padding: 1rem;
  border-radius: 8px;
  margin-bottom: 1.5rem;
  text-align: center;
}
.alert-warning {
  background-color: rgba(251, 191, 36, 0.1);
  border: 1px solid rgba(251, 191, 36, 0.5);
  color: #b45309;
}
[data-theme="dark"] .alert-warning { color: #fbbf24; }

/* Tables */
table {
  width: 100%;
  border-collapse: collapse;
  margin-bottom: 2rem;
}
th, td {
  padding: 0.75rem;
  border-bottom: 1px solid var(--border);
  text-align: left;
}
th {
  font-weight: 600;
  color: var(--text-primary);
}

/* Responsive */
@media (max-width: 768px) {
  .nav-links {
    display: none; /* Add JS toggle logic later */
    flex-direction: column;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: var(--bg-primary);
    border-bottom: 1px solid var(--border);
    padding: 1rem;
  }
  
  .nav-links.active {
    display: flex;
  }

  .menu-toggle {
    display: block;
  }

  h1 { font-size: 2rem; }
  h2 { font-size: 1.75rem; }
}