body { font-family: Arial, sans-serif; margin:0; padding:0; background-color:#0f111a; color:#fff; }
header { display:flex; justify-content:space-between; align-items:center; padding:1rem; background:#0b0c17; }
header .logo { font-weight:bold; font-size:1.5rem; color:#00b4d8; }
nav a { margin-left:1rem; color:#fff; text-decoration:none; }
nav a.contact { background:#00b4d8; padding:0.3rem 0.6rem; border-radius:4px; }
main { padding:2rem; }
section { margin-bottom:2rem; }
.diagram { width:100%; height:auto; border:1px solid #333; border-radius:6px; }
footer { text-align:center; padding:1rem; background:#0b0c17; color:#888; }