JSFiddle - React, Tailwind, and code Playground

HTML

<div>
  <button class="close" aria-label="Close"></button>
</div>

CSS

/*Button to quit the form*/
.close {
    vertical-align: middle;
    border: none;
    color: inherit;
    border-radius: 50%;
    background: transparent;
    position: relative;
    width: 20px;
    height: 20px;
    opacity: 0.6;
}
.close:focus,
.close:hover {
    opacity: 1;
    background: rgba(128, 128, 128, 0.5);
}
.close:active {
    background: rgba(128, 128, 128, 0.9);
}
/* tines of the X */
.close::before,
.close::after {
    content: " ";
    position: absolute;
    top: 50%;
    right: 0;
    height: 20px;
    width: 3px;
    background-color: currentColor;
}
.close::before {
    transform: translate(-50%, -50%) rotate(45deg);
}
.close::after {
    transform: translate(-50%, -50%) rotate(-45deg);
}