@import url('https://fonts.googleapis.com/css?family=Montserrat:600&display=swap');
*{
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}
body{
  height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
 background: black;
}
.container{
  background: linear-gradient(45deg,#e8effd 0%,#d6e3f5 100%);
  padding: 100px;
}
.btn{
  position: relative;
  display: inline-flex;
  height: 60px;
  width: 200px;
  border-radius: 5px;
  margin: 17px 20px;
  overflow: hidden;
  transition: all .4s;
}
.btn .inner{
  position: absolute;
  width: 300%;
  height: 100%;
  left: -100%;
  z-index: -1;
  transition: all .4s;
}
.btn button{
  height: 100%;
  width: 100%;
  border: none;
  outline: none;
  background: none;
  color: white;
  font-size: 20px;
  cursor: pointer;
  letter-spacing: 1px;
  text-transform: uppercase;
  font-family: 'Montserrat', sans-serif;
}
.btn:hover{
  transform: scale(1.03);
}
.btn:hover .inner{
  left: 0;
}
.btn1 .inner{
  background: -webkit-linear-gradient(right, #00dbde,#fc00ff,#00dbde,#fc00ff);
}
.btn2 .inner{
  background: -webkit-linear-gradient(right, #f7b733,#fc4a1a,#f7b733,#fc4a1a);
}
.btn3 .inner{
  background: -webkit-linear-gradient(right, #f1c40e,#26a65b,#f1c40e,#26a65b);
}
.btn4 .inner{
  background: -webkit-linear-gradient(right, #43cea2,#185a9d,#43cea2,#185a9d);
}