Simple pure css spinner

The CSS:

spinner.css:

.spinner,
.spinner:after {
  border-radius: 50%;
  width: 10em;
  height: 10em;
}

.spinner {
  margin: 60px auto;
  font-size: 10px;
  position: relative;
  text-indent: -9999em;
  border-top: 1.1em solid rgba(0, 0, 0, 0.2);
  border-right: 1.1em solid rgba(0, 0, 0, 0.2);
  border-bottom: 1.1em solid rgba(0, 0, 0, 0.2);
  border-left: 1.1em solid rgba(0, 0, 0, 0.6);
  -webkit-transform: translateZ(0);
  -ms-transform: translateZ(0);
  transform: translateZ(0);
  -webkit-animation: spin 2.1s infinite linear;
  animation: spin 2.1s infinite linear;
}

@keyframes spin {
  0% {
    -webkit-transform: rotate(0deg);
    transform: rotate(0deg);
  }
  100% {
    -webkit-transform: rotate(360deg);
    transform: rotate(360deg);
  }
}

React example:

Spinner.jsx:

import React from "react";
import "./spinner.css";

const Spinner = () => <div className="spinner"></div>;

export default Spinner;

Source: https://projects.lukehaas.me/css-loaders/