how to make download button in css code example

Example: button download css

<style>
.buttonYN {
  margin: 10em auto 0;
  display: inline-block;
  font-size: 1.15em;
  position: relative;
  text-align: center;
  padding: 0.5em 1em;
  background: linear-gradient(45deg, #59adeb, #40c3af);
  color: #fff;
  box-shadow: 0 0.2em 0.2em rgba(0,0,0,0.25);
  border-radius: 0.2em;
  transition: box-shadow 0.2s ease-in-out;
  cursor: pointer;
}
.buttonYN:active {
  background-color: #ccc;
  box-shadow: 0 0 6px rgba(0,121,238,0.6);
  transition: box-shadow 0.1s ease-in-out;
}
.buttonYN:after {
  content: "\0021e7";
  position: absolute;
  top: -0.4em;
  left: 0;
  right: 0;
  display: block;
  transform: rotate(180deg);
  font-size: 5em;
  opacity: 0;
  text-shadow: 0 0 1em #000;
  transition: opacity 0.3s ease-in-out, font-size 0.3s ease-in-out, top 0.3s ease-in-out;
  box-sizing: border-box;
  text-align: center;
  color: #fff;
}
.buttonYN:active:after {
  font-size: 1em;
  opacity: 1;
  transition: none;
  top: 0.3em;
}
.buttonYN:hover {
  box-shadow: 0 0.1em 0.25em rgba(0,0,0,0.25);
}
</style>

<div style='margin: 0; padding: 0; text-align: center; font-family: sans-serif;'>
  <div class="buttonYN">Download</div>
  </div>