step1-tooltip.css

step1-tooltip.css

button{
  margin:auto;
  background: #3498db;
  font-family: Arial;
  color: #ffffff;
  font-size: 14px;
}
[tooltip]{
  margin:20px;
  position:relative;
}
[tooltip]::before {
    content: "";
    position: absolute;
    top:-6px;
    left:50%;
    transform: translateX(-50%);
    border-width: 4px 6px 0 6px;
    border-style: solid;
    border-color: rgba(0,0,0,0.7) transparent transparent     transparent;
    z-index: 100;
}
[tooltip]::after {
    content: attr(tooltip);
    position: absolute;
    left:50%;
    top:-6px;
    transform: translateX(-50%)   translateY(-100%);
    background: rgba(0,0,0,0.7);
    text-align: center;
    color: #fff;
    padding:4px 2px;
    font-size: 12px;
    min-width: 80px;
    border-radius: 5px;
    pointer-events: none;
}