@media (max-width: 768px) {
  #site-header .main-nav {
    position: absolute;
    top: 100%;
    right: 0;
    z-index: 1100;
    width: auto;
    flex-basis: auto;
    max-width: calc(100vw - 24px);
    margin-top: 8px;
    padding: 10px 34px;
    white-space: nowrap;
    background: #fff;
    border: 1px solid var(--line);
    border-radius: 10px;
    box-shadow: 0 12px 28px rgba(0, 0, 0, .16);
  }
}