:root {
  --side-control-size: 48px;
  --side-control-menu-item-height: 36px;
}

.side-lang-switch {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: flex-end;
  font-family: 'IBM Plex Mono', monospace;
  font-size: 11px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.side-lang-switch::after {
  content: attr(data-tooltip);
  position: absolute;
  right: calc(100% + 10px);
  top: calc(var(--side-control-size) / 2);
  transform: translateY(-50%);
  background: var(--fg);
  color: var(--bg);
  padding: 6px 10px;
  font-size: 12px;
  font-family: 'IBM Plex Mono', monospace;
  letter-spacing: 0.02em;
  line-height: 1;
  text-transform: none;
  white-space: nowrap;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.2s ease;
}

@media (any-hover: hover) {
  .side-lang-switch:not(.is-open):hover::after {
    opacity: 1;
  }
}

.side-lang-toggle {
  width: var(--side-control-size);
  height: var(--side-control-size);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--fg);
  background: var(--bg);
  color: var(--fg);
  font: inherit;
  letter-spacing: inherit;
  text-transform: inherit;
  cursor: pointer;
  appearance: none;
  transition: background 0.2s ease, color 0.2s ease;
}

.side-lang-toggle:hover,
.side-lang-switch.is-open .side-lang-toggle {
  background: var(--fg);
  color: var(--bg);
}

.side-lang-menu {
  position: absolute;
  top: 0;
  right: calc(100% + 8px);
  display: flex;
  flex-direction: row;
  gap: 8px;
  opacity: 0;
  transform: translateX(6px);
  pointer-events: none;
  transition: opacity 0.2s ease, transform 0.2s ease;
}

.side-lang-switch.is-open .side-lang-menu {
  opacity: 1;
  transform: translateX(0);
  pointer-events: auto;
}

.side-lang-menu a {
  width: var(--side-control-size);
  height: var(--side-control-size);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--fg);
  background: var(--bg);
  color: var(--fg);
  text-decoration: none;
  transition: background 0.2s ease, color 0.2s ease;
}

.side-lang-menu a:hover,
.side-lang-menu a.is-active {
  background: var(--fg);
  color: var(--bg);
}

@media (max-width: 768px) {
  :root {
    --side-control-size: 44px;
  }
}