.btn {
  border-radius: 10px;
}

* {
  box-sizing: border-box;
}

*, *::before, *::after {
  box-sizing: inherit;
  margin: 0;
  padding: 0;
}

button {
  cursor: pointer;
  position: relative;
  margin-right: 7px;
  font-size: 12px;
  padding: 3px;
  border: none;
  outline: none;
  background-color: transparent;
}

button::before {
  content: attr(data-title);
  position: absolute;
  display: none;
  right: 0;
  top: -50px;
  background-color: rgba(0, 0, 0, 0.6);
  color: #fff;
  font-weight: bold;
  padding: 4px 6px;
  word-break: keep-all;
  white-space: pre;
}

button:hover::before {
  display: inline-block;
}