/* Enhanced UI CSS with modern features */
:root {
  /* Light theme variables */
  --bg-primary-light: #ffffff;
  --text-primary-light: #1a1a1a;
  --accent-light: #ff4500;
  --secondary-light: #f4f4f4;
  
  /* Dark theme variables */
  --bg-primary-dark: #121212;
  --text-primary-dark: #ffffff;
  --accent-dark: #ff5722;
  --secondary-dark: #1e1e1e;

  /* Common variables */
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 2rem;
  --spacing-xl: 4rem;
  
  --border-radius: 8px;
  --transition-speed: 0.3s;
}

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

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  line-height: 1.6;
  transition: background-color var(--transition-speed), color var(--transition-speed);
  scroll-behavior: smooth;
}

/* Light theme (default) */
body {
  background-color: var(--bg-primary-light);
  color: var(--text-primary-light);
}

/* Dark theme */
body[data-theme="dark"] {
  background-color: var(--bg-primary-dark);
  color: var(--text-primary-dark);
}

/* Typography improvements */
h1, h2, h3, h4, h5, h6 {
  margin-bottom: var(--spacing-md);
  line-height: 1.3;
  font-weight: 700;
}

h1 { font-size: 2.5rem; }
h2 { font-size: 2rem; }
h3 { font-size: 1.75rem; }

p {
  margin-bottom: var(--spacing-md);
  font-size: 1.1rem;
  max-width: 70ch; /* Optimal reading width */
}

/* Modern Card Design */
.card {
  background: var(--bg-primary-light);
  border-radius: var(--border-radius);
  padding: var(--spacing-lg);
  margin: var(--spacing-md) 0;
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
  transition: transform var(--transition-speed), box-shadow var(--transition-speed);
}

.card:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 12px rgba(0, 0, 0, 0.15);
}

/* Enhanced Navigation */
.nav-container {
  position: sticky;
  top: 0;
  backdrop-filter: blur(10px);
  z-index: 1000;
  padding: var(--spacing-sm) var(--spacing-lg);
}

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

.nav-links a {
  color: inherit;
  text-decoration: none;
  position: relative;
  padding: var(--spacing-xs) 0;
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--accent-light);
  transition: width var(--transition-speed);
}

.nav-links a:hover::after {
  width: 100%;
}

/* Enhanced Buttons */
.button {
  display: inline-block;
  padding: var(--spacing-sm) var(--spacing-lg);
  border-radius: var(--border-radius);
  background: var(--accent-light);
  color: white;
  text-decoration: none;
  font-weight: 600;
  transition: transform var(--transition-speed), box-shadow var(--transition-speed);
}

.button:hover {
  transform: translateY(-1px);
  box-shadow: 0 4px 8px rgba(255, 69, 0, 0.3);
}

/* Responsive Images */
img {
  max-width: 100%;
  height: auto;
  border-radius: var(--border-radius);
}

/* Layout Containers */
.container {
  width: 90%;
  max-width: 1200px;
  margin: 0 auto;
  padding: var(--spacing-md);
}

/* Grid Layout */
.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: var(--spacing-lg);
}

/* Dark mode toggle */
.theme-toggle {
  position: fixed;
  bottom: var(--spacing-lg);
  right: var(--spacing-lg);
  padding: var(--spacing-sm);
  border-radius: 50%;
  background: var(--accent-light);
  border: none;
  cursor: pointer;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
  z-index: 1000;
}

/* Animations */
@keyframes fadeIn {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}

.animate-in {
  animation: fadeIn 0.6s ease-out forwards;
}

/* Media Queries */
@media (max-width: 768px) {
  h1 { font-size: 2rem; }
  h2 { font-size: 1.75rem; }
  h3 { font-size: 1.5rem; }
  
  .container {
    width: 95%;
  }
  
  .nav-links {
    flex-direction: column;
    gap: var(--spacing-sm);
  }
}