body { margin:0; font-family:system-ui,-apple-system,sans-serif; background:#0a0a0a; color:#ddd; line-height:1.6; }
.topnav {
  max-width:960px; margin:0 auto; padding:0 20px; background:#0a0a0a; border-bottom:1px solid #222; overflow:hidden;
}
.topnav a {
  float:left; display:block; color:#ddd; text-align:center; padding:14px 16px; text-decoration:none;
}
.topnav a:hover, .topnav a.active { color:#22c55e; }
.topnav .icon {
  float:right; display:none; padding:14px 16px; font-size:28px; cursor:pointer;
}
.container { max-width:960px; margin:0 auto; padding:40px 20px; }
@media screen and (max-width:768px) {
  .topnav a:not(:first-child) { display:none; }
  .topnav a.icon { display:block; }
  .topnav.responsive { position:relative; }
  .topnav.responsive a { float:none; display:block; text-align:left; }
  .topnav.responsive .icon { position:absolute; right:0; top:0; }
}
.kit { background:#111; border-radius:12px; padding:25px; margin:20px 0; cursor:pointer; }
details summary { cursor:pointer; font-weight:600; color:#22c55e; font-size:1.1rem; }