.sp-menu {
  display: none;
}

@media screen and (max-width: 768px) {
  .sp-menu {
    display: block;
    position: fixed;
    top: 12px;
    right: 12px;
    z-index: 9999;
  }

  .hamburger {
    width: 48px;
    height: 48px;
    background: #8b0000;
    border: none;
    border-radius: 4px;
    cursor: pointer;
  }

  .hamburger span {
    display: block;
    width: 26px;
    height: 2px;
    background: #fff;
    margin: 6px auto;
    transition: 0.3s;
  }

  .sp-nav {
    display: none;
    position: fixed;
    top: 68px;
    right: 12px;
    width: 240px;
    background: #fff;
    border: 1px solid #8b0000;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
    padding: 0;
    margin: 0;
    list-style: none;
  }

  .sp-nav li {
    border-bottom: 1px solid #eee;
  }

  .sp-nav a {
    display: block;
    padding: 14px 16px;
    color: #8b0000;
    text-decoration: none;
    font-weight: bold;
  }

  .sp-menu.is-open .sp-nav {
    display: block;
  }

  .sp-menu.is-open .hamburger span:nth-child(1) {
    transform: translateY(8px) rotate(45deg);
  }

  .sp-menu.is-open .hamburger span:nth-child(2) {
    opacity: 0;
  }

  .sp-menu.is-open .hamburger span:nth-child(3) {
    transform: translateY(-8px) rotate(-45deg);
  }
}