@media (max-width:900px){
  .site-header nav{align-items:flex-start}

  .nav-menu summary{
    display:inline-flex;
    align-items:flex-start;
    line-height:1.2;
  }

  .nav-menu summary:after{
    display:block;
    margin-top:-1px;
    line-height:1;
  }
}