.navtoggle{
  display:none;
  width:40px;height:40px;border-radius:10px;border:1px solid var(--line);
  background:var(--paper);align-items:center;justify-content:center;cursor:pointer;
}
.navtoggle span,.navtoggle span::before,.navtoggle span::after{
  content:"";display:block;width:18px;height:2px;background:var(--ink);position:relative;
}
.navtoggle span::before{position:absolute;top:-6px;}
.navtoggle span::after{position:absolute;top:6px;}

@media (max-width:900px){
  .navtoggle{display:flex;}
  nav.mainnav{
    display:none;
    position:absolute;top:100%;left:0;right:0;background:var(--paper);
    border-bottom:1px solid var(--line);flex-direction:column;gap:0;padding:8px 24px 16px;
    box-shadow:0 20px 40px -28px rgba(11,42,107,.3);
  }
  nav.mainnav a{padding:12px 0;border-bottom:1px solid var(--line-soft);}
  .topbar.open nav.mainnav{display:flex;}
  .head-right .btn-primary{padding:9px 16px;font-size:13px;}
}