.site-header { background:#fff; border-bottom:1px solid #e6e6e6; }
.header-top { display:flex; justify-content:space-between; align-items:center; padding:12px 20px; }
.site-branding img { max-height:60px; }
.main-menu { display:flex; gap:18px; list-style:none; padding:0; margin:0; }
.menu-toggle { display:none; }

/* スマホ */
@media (max-width:768px){
  .main-menu { display:none; flex-direction:column; }
  .main-menu.open { display:flex; }
  .menu-toggle { display:block; }
}