div.absolute0 {
position: absolute;
top: 0px;
left: 0px;
}
div.absolute5
{
 position: absolute;
 bottom: 0px;
 right: 0px;
}

div.absolute {
position: absolute;
top: 100px;
left: 250px;
width: 1010px;
height: 510px;
;
}
div.absolute1 
{
position: absolute;
top: 0px;
left: 310px;
width: 210px;
height: 480px;

}
div.absolute2 
{
position: absolute;
top: 5px;
left: 10px;
width: 110px;
height: 110px;

}
div.absolute3 
{
position: absolute;
top: 80px;
left: 10px;
width: 100px;
height: 110px;

}
div.absolute4
{
 position: absolute;
 top: 50px;
 left: 10px;
}
div.absolute6
{
 position: absolute;
 bottom: 0px;
 left: 0px;
}


.container{
  position:absolute;
  left:530px;
  top:100px;
 }
.btn{
  border: 1px solid #3498db;
  background: none;
  padding: 15px 50px;
  font-size: 20px;
  font-family: "montserrat";
  cursor: pointer;
  margin: 10px;
  transition: 0.8s;
  position: relative;
  overflow: hidden;
  border-radius: 5px;
  box-shadow: 1px 1px 5px black;
}
.btn1,.btn2{
  color: #3498db;
}
.btn3,.btn4{
  color: #fff;
}
.btn1:hover,.btn2:hover{
  color: #fff;
}
.btn3:hover,.btn4:hover{
  color: #3498db;
}
.btn::before{
  content: "";
  position: absolute;
  left: 0;
  width: 100%;
  height: 0%;
  background: #3498db;
  z-index: -1;
  transition: 0.8s;
}
.btn1::before,.btn3::before{
  top: 0;
  border-radius: 0 0 50% 50%;
}
.btn2::before,.btn4::before{
  bottom: 0;
  border-radius: 50% 50% 0 0;
}
.btn3::before,.btn4::before{
  height: 180%;
}
.btn1:hover::before,.btn2:hover::before{
  height: 180%;
}
.btn3:hover::before,.btn4:hover::before{
  height: 0%;
}