html {
  font-size: 62.5%;
  font-family: "Poppins", sans-serif;
}
* {
  box-sizing: border-box;
}
body {
  padding: 1rem;
}
.btn {
  cursor: pointer;
  border: 0;
  padding: 1rem 2.5rem;
  border-radius: 5rem;
  text-transform: uppercase;
  text-align: center;
  font-size: 1.6rem;
  font-family: "Poppins";
  overflow: hidden;
  position: relative;
  z-index: 1;
}
.btn:before {
  content: "";
  position: absolute;
  z-index: -1;
  background-color: #ff7870;
}
.btn--left:before {
  top: 0;
  left: 0;
  width: 0;
  height: 100%;
  transition: width 0.25s linear;
}
.btn--left:hover:before {
  width: 100%;
}
.btn--right:before {
  top: 0;
  right: 0;
  width: 0;
  height: 100%;
  transition: width 0.25s linear;
}
.btn--right:hover:before {
  width: 100%;
}
.btn--top:before {
  top: 0;
  left: 0;
  width: 100%;
  height: 0;
  transition: height 0.25s linear;
}
.btn--top:hover:before {
  height: 100%;
}
.btn--bottom:before {
  bottom: 0;
  left: 0;
  width: 100%;
  height: 0;
  transition: height 0.25s linear;
}
.btn--bottom:hover:before {
  height: 100%;
}