:root {
  /* Premium Color Palette */
  --bg-primary: #ffffff;
  --bg-secondary: #f4f5f7;
  --text-primary: #1a1a1a;
  --text-secondary: #5e636e;
  --accent-color: #4f46e5;
  --accent-hover: #4338ca;
  --border-color: #e5e7eb;
  --card-bg: #ffffff;
  --card-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.05), 0 2px 4px -1px rgba(0, 0, 0, 0.03);
  --card-shadow-hover: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
  
  /* Typography */
  --font-body: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --font-heading: 'Outfit', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  
  /* Spacing & Layout */
  --max-width: 1200px;
  --transition: all 0.2s ease-in-out;
}

[data-theme="dark"] {
  --bg-primary: #0f1115;
  --bg-secondary: #1a1d24;
  --text-primary: #f3f4f6;
  --text-secondary: #9ca3af;
  --accent-color: #6366f1;
  --accent-hover: #818cf8;
  --border-color: #2d3748;
  --card-bg: #1f222b;
  --card-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.2);
  --card-shadow-hover: 0 10px 15px -3px rgba(0, 0, 0, 0.3);
}

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

body {
  font-family: var(--font-body);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  transition: background-color 0.3s ease, color 0.3s ease;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  font-weight: 700;
  line-height: 1.2;
}

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

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

/* Typography elements */
.gallery-header {
  text-align: center;
  padding: 4rem 1rem 3rem;
  background: linear-gradient(to bottom, var(--bg-secondary) 0%, var(--bg-primary) 100%);
  margin-bottom: 2rem;
  border-bottom: 1px solid var(--border-color);
}

.gallery-header h1 {
  font-size: 3rem;
  margin-bottom: 1.5rem;
  background: linear-gradient(135deg, var(--accent-color), #8b5cf6);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* Layout */
.container {
  flex: 1;
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* Navigation Bar */
.navbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 2rem;
  background-color: rgba(var(--bg-primary), 0.8);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border-color);
  position: sticky;
  top: 0;
  z-index: 1000;
}

.nav-brand a {
  font-family: var(--font-heading);
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--text-primary);
}

.nav-controls {
  display: flex;
  align-items: center;
  gap: 1rem;
}

#authContainer {
  display: flex;
  align-items: center;
}

#userMenu {
  display: flex;
  align-items: center;
  gap: 1rem;
}

/* Buttons */
.btn-primary {
  background-color: var(--accent-color);
  color: white;
  border: none;
  padding: 0.5rem 1.25rem;
  border-radius: 9999px;
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 0.95rem;
  cursor: pointer;
  transition: var(--transition);
  box-shadow: 0 4px 6px rgba(79, 70, 229, 0.2);
}

.btn-primary:hover {
  background-color: var(--accent-hover);
  transform: translateY(-1px);
  box-shadow: 0 6px 8px rgba(79, 70, 229, 0.3);
}

.btn-secondary {
  background-color: var(--bg-secondary);
  color: var(--text-primary);
  border: 1px solid var(--border-color);
  padding: 0.5rem 1.25rem;
  border-radius: 9999px;
  font-family: var(--font-heading);
  font-weight: 500;
  font-size: 0.95rem;
  cursor: pointer;
  transition: var(--transition);
}

.btn-secondary:hover {
  background-color: var(--border-color);
}

.btn-link {
  color: var(--text-secondary);
  font-weight: 500;
  padding: 0.5rem;
}

.btn-link:hover {
  color: var(--text-primary);
}

.btn-sm {
  padding: 0.35rem 0.75rem;
  font-size: 0.8rem;
}

.btn-icon {
  background: transparent;
  border: none;
  color: var(--text-primary);
  cursor: pointer;
  padding: 0.5rem;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background-color 0.2s;
}

.btn-icon:hover {
  background-color: var(--bg-secondary);
}

/* Search Bar */
.search-bar {
  max-width: 600px;
  margin: 0 auto;
  position: relative;
}

.search-bar input {
  width: 100%;
  padding: 1rem 1.5rem;
  font-size: 1.1rem;
  border: 2px solid var(--border-color);
  border-radius: 9999px;
  background-color: var(--bg-primary);
  color: var(--text-primary);
  font-family: var(--font-body);
  transition: var(--transition);
  box-shadow: var(--card-shadow);
}

.search-bar input:focus {
  outline: none;
  border-color: var(--accent-color);
  box-shadow: 0 0 0 4px rgba(79, 70, 229, 0.1);
}

/* Grid System */
.codelab-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 2rem;
  padding: 2rem 0;
}

/* Cards (Injected by JS later, styling prepared here) */
.codelab-card {
  background-color: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: 16px;
  overflow: hidden;
  transition: var(--transition);
  box-shadow: var(--card-shadow);
  display: flex;
  flex-direction: column;
  height: 100%;
}

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

.codelab-card-image {
  width: 100%;
  height: 160px;
  object-fit: cover;
  background-color: var(--bg-secondary);
}

.codelab-card-content {
  padding: 1.5rem;
  flex: 1;
  display: flex;
  flex-direction: column;
}

.codelab-card-title {
  font-size: 1.25rem;
  margin-bottom: 0.75rem;
  color: var(--text-primary);
}

.codelab-card-desc {
  color: var(--text-secondary);
  font-size: 0.95rem;
  margin-bottom: 1.5rem;
  flex: 1;
}

.codelab-card-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  border-top: 1px solid var(--border-color);
  padding-top: 1rem;
  font-size: 0.85rem;
  color: var(--text-secondary);
}

/* Footer */
.footer {
  background-color: var(--bg-secondary);
  border-top: 1px solid var(--border-color);
  padding: 2rem;
  text-align: center;
  margin-top: 4rem;
  color: var(--text-secondary);
  font-size: 0.9rem;
}

/* Auth state overriding inline styles locally where applicable */
[style*="display: none;"] {
  display: none !important;
}

/* Toggle Switch */
.toggle-switch {
  position: relative;
  display: inline-block;
  width: 36px;
  height: 20px;
}

.toggle-switch input {
  opacity: 0;
  width: 0;
  height: 0;
}

.toggle-slider {
  position: absolute;
  cursor: pointer;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: var(--border-color);
  transition: .3s;
  border-radius: 20px;
}

.toggle-slider:before {
  position: absolute;
  content: "";
  height: 14px;
  width: 14px;
  left: 3px;
  bottom: 3px;
  background-color: white;
  transition: .3s;
  border-radius: 50%;
  box-shadow: 0 1px 3px rgba(0,0,0,0.2);
}

input:checked + .toggle-slider {
  background-color: #10b981;
}

input:checked + .toggle-slider:before {
  transform: translateX(16px);
}