*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}html{line-height:1.5;font-size:16px}body{font-family:-apple-system,BlinkMacSystemFont,'Segoe UI',Roboto,Oxygen,Ubuntu,Cantarell,sans-serif;line-height:1.6;color:#222;background:#f8f9fa}.container{max-width:1200px;margin:0 auto;padding:0 20px}a{color:#2563eb;text-decoration:none}a:hover{text-decoration:underline}header{background:#fff;border-bottom:2px solid #e9ecef;padding:1rem 0;margin-bottom:2rem}nav{display:flex;justify-content:space-between;align-items:center}.logo{font-size:1.5rem;font-weight:700;color:#212529}.nav-menu{display:flex;list-style:none;gap:1.5rem}.nav-menu a{color:#495057;font-weight:500}.nav-menu a:hover{color:#2563eb}main{background:#fff;padding:3rem 2rem;margin:2rem auto;max-width:900px;border-radius:8px;box-shadow:0 2px 10px rgba(0,0,0,0.05)}h1{font-size:2.5rem;font-weight:700;color:#212529;line-height:1.2;margin-bottom:1.5rem}h2{font-size:1.8rem;font-weight:600;color:#343a40;margin:2rem 0 1rem 0}h3{font-size:1.3rem;font-weight:600;color:#495057;margin:1.5rem 0 0.5rem 0}p{margin-bottom:1rem;color:#495057}ul{margin-left:2rem;margin-bottom:1rem}li{margin-bottom:0.5rem}footer{text-align:center;padding:2rem;margin-top:4rem;color:#6c757d;border-top:1px solid #e9ecef}