:root{--primary: #2c3e50;--secondary: #3498db;--accent: #e74c3c;--light: #ecf0f1;--dark: #2c3e50;--gray: #95a5a6;--transition: all .3s ease}*{box-sizing:border-box;margin:0;padding:0}html{scroll-behavior:smooth}body{font-family:Segoe UI,Tahoma,Geneva,Verdana,sans-serif;background-color:#f9f9f9;color:#333;line-height:1.6}.container{max-width:1200px;margin:0 auto;padding:0 20px}section{padding:100px 0}:root{--header-height: 70px}main{margin-top:var(--header-height)}@media (max-width: 768px){main{margin-top:calc(var(--header-height) + 0px)}}