/* Global Styles */
* { box-sizing: border-box; }
body { font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif; }
a { transition: color 0.3s ease; }
img { max-width: 100%; height: auto; }

/* Layout Variant D Specific Styles */
.ui-style-4 .nav { box-shadow: 0 2px 10px rgba(0,0,0,0.1); }
.ui-style-4 .card { border: 1px solid #e0e0e0; }
.ui-style-4 .card:hover { border-color: #1976d2; }