.mobile-menu-toggle {
  display: none;
}

.mobile-menu-scrim {
  display: none;
}

.back-to-top {
  position: fixed;
  right: 24px;
  bottom: 24px;
  z-index: 50;
  display: inline-flex;
  width: 44px;
  height: 44px;
  align-items: center;
  justify-content: center;
  padding: 0;
  border: 1px solid rgba(30, 35, 35, .16);
  border-radius: 50%;
  color: #fff;
  background: var(--ink);
  box-shadow: 0 10px 24px rgba(30, 35, 35, .2);
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transform: translateY(10px);
  transition: opacity .18s ease, transform .18s ease, background .18s ease, visibility .18s ease;
}

.back-to-top span {
  font-size: 23px;
  font-weight: 700;
  line-height: 1;
}

.back-to-top.is-visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.back-to-top:hover {
  background: var(--rose-dark);
}

@media (max-width: 760px) {
  body.is-mobile-menu-open {
    overflow: hidden;
  }

  .header-inner {
    position: relative;
    grid-template-columns: minmax(0, 1fr) 42px;
    gap: 0;
    padding: 10px 0;
  }

  .mobile-menu-toggle {
    display: inline-flex;
    width: 42px;
    height: 42px;
    align-items: center;
    justify-content: center;
    gap: 4px;
    flex-direction: column;
    padding: 0;
    border: 1px solid var(--line);
    border-radius: var(--radius);
    background: #fff;
    cursor: pointer;
  }

  .mobile-menu-toggle span {
    display: block;
    width: 18px;
    height: 2px;
    border-radius: 999px;
    background: var(--ink);
    transition: transform .18s ease, opacity .18s ease;
  }

  .header.is-menu-open .mobile-menu-toggle span:nth-child(1) {
    transform: translateY(6px) rotate(45deg);
  }

  .header.is-menu-open .mobile-menu-toggle span:nth-child(2) {
    opacity: 0;
  }

  .header.is-menu-open .mobile-menu-toggle span:nth-child(3) {
    transform: translateY(-6px) rotate(-45deg);
  }

  .nav {
    display: none;
  }

  .header.is-menu-open .nav {
    display: grid;
    position: absolute;
    top: calc(100% + 10px);
    right: 0;
    left: 0;
    z-index: 2;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 8px;
    max-height: calc(100dvh - 86px);
    margin: 0;
    padding: 12px;
    border: 1px solid var(--line);
    border-radius: var(--radius);
    background: #fff;
    box-shadow: var(--shadow);
    overflow-y: auto;
    overscroll-behavior: contain;
  }

  .nav a {
    padding: 10px 8px;
    border: 1px solid var(--line);
    border-radius: var(--radius);
    background: var(--paper);
    text-align: center;
    font-size: 14px;
  }

  .mobile-menu-scrim {
    position: fixed;
    inset: 0;
    z-index: 35;
    display: block;
    background: rgba(30, 35, 35, .28);
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
    transition: opacity .18s ease, visibility .18s ease;
  }

  .mobile-menu-scrim.is-visible {
    opacity: 1;
    visibility: visible;
    pointer-events: auto;
  }

  .back-to-top {
    right: 16px;
    bottom: 16px;
  }
}