:root {
  --pageBlack: #262626;
  --pageYellow: #ffd83e;
  --pagePurple: #552b55;
  --pageRed: #E1332d;
  --pageGreen: #2ce771;
  --pageGrey: #212121;

}
body {
  margin: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  height: 100vh;
  background-color: var(--pageGrey);
}
button {
  border: none;
  padding: 12px 40px;
  background-color: rgb(117, 129, 39);
  color: white;
  font-family: Univers;
  font-size: 22px;
  text-transform: uppercase;
  cursor: pointer;
  position: relative;
}
button:before {
  content: '';
  position: absolute;
  width: 24px;
  height: 24px;
  top: -5px;
  left: -5px;
  border-top: 2px solid goldenrod;
  border-left: 2px solid goldenrod;
  transition: all .4s;
}
button:hover:before {
  height: 100%;
  width: 100%;
}
button:after {
  content: '';
  position: absolute;
  width: 24px;
  height: 24px;
  bottom: -5px;
  right: -5px;
  border-bottom: 2px solid goldenrod;
  border-right: 2px solid goldenrod;
  transition: all .4s;
}
button:hover:after {
  height: 100%;
  width: 100%;
}