Keyboard Shortcut Tooltip

<div class="nuda-kbdtt-wrap">
  <button class="nuda-kbdtt-trigger">Save</button>
  <div class="nuda-kbdtt">
    Save document
    <span class="nuda-kbdtt__keys">
      <kbd>⌘</kbd>
      <kbd>S</kbd>
    </span>
  </div>
</div>

.nuda-kbdtt-wrap {
  position: relative;
  display: inline-block;
}

.nuda-kbdtt-trigger {
  padding: 6px 12px;
  background: rgba(255,255,255,.04);
  border: 1px solid rgba(255,255,255,.08);
  color: #fafafa;
  border-radius: 8px;
  font-size: 12px;
  cursor: pointer;
  transition: background .25s;
}

.nuda-kbdtt-wrap:hover .nuda-kbdtt-trigger {
  background: rgba(255,255,255,.07);
}

.nuda-kbdtt {
  position: absolute;
  left: 50%;
  bottom: calc(100% + 8px);
  transform: translateX(-50%) translateY(4px);
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 6px 10px;
  background: #09090b;
  border: 1px solid rgba(255,255,255,.1);
  border-radius: 7px;
  color: #fafafa;
  font-size: 11px;
  white-space: nowrap;
  opacity: 0;
  pointer-events: none;
  transition: opacity .25s,transform .35s cubic-bezier(.16,1,.3,1);
  z-index: 10;
}

.nuda-kbdtt-wrap:hover .nuda-kbdtt {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
  pointer-events: auto;
}

.nuda-kbdtt__keys {
  display: inline-flex;
  gap: 3px;
}

.nuda-kbdtt__keys kbd {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 18px;
  height: 16px;
  padding: 0 4px;
  background: rgba(255,255,255,.06);
  border: 1px solid rgba(255,255,255,.1);
  border-radius: 4px;
  font-family: ui-monospace,SFMono-Regular,Menlo,monospace;
  font-size: 10px;
  color: #a0a0a8;
  box-shadow: inset 0 -1px 0 rgba(0,0,0,.3);
}