index.css

body {
  font-family: "Lato", sans-serif;
  transition: background-color .5s;
  background-image: url(background.jpg);
  background-size: cover;
  overflow: hidden;

  
}


.sidenav {
  height: 100%;
  width: 0;
  position: absolute;
  float: top;
  z-index: 1;
  top: 0;
  left: 0;
  background-color: #111;
  overflow-x: hidden;
  transition: 0.5s;
  padding-top: 60px;
}

.sidenav a {
  padding: 8px 8px 8px 5px;
  text-decoration: none;
  font-size: 25px;
  color: #818181;
  display: block;
  transition: 0.3s;
}

.sidenav a:hover {
  color: #f1f1f1;
}

.sidenav .closebtn {
  position: absolute;
  top: 0;
  right: 25px;
  font-size: 36px;
  margin-left: 50px;
}

#main {
  transition: margin-left .3s;
  padding: 10px;
  background-color: transparent

}

@media screen and (max-height: 450px) {
  .sidenav {padding-top: 15px;}
  .sidenav a {font-size: 18px;}
}



h1{
    text-align: center;
    font-size: 60px;
   
}

p{
    text-align: center;
    font-size: 30px;
    
}

ul{
  float: right;
  list-style-type: none;
  margin-top: 15vw;
}
ul li{
  display: block;
  max-width:1200px;
  margin:0 auto;
  float: right;
}
ul li a{
  text-decoration: none;
  color: #000;
  padding: 3px 20px;
  border: 1px solid transparent;
    transition: 0.6s ease;
    font-size: 23px;
}

ol{
  float: center;
  list-style-type: none;
  margin-top: 0px;
  margin-left: 35vw;
}
ol li{
  display: block;
  max-width:1200px;
    margin:0 auto;
}
ol li a{
  text-decoration: none;
  color: #000;
  padding: 3px 20px;
  border: 1px solid transparent;
    transition: 0.6s ease;
    font-size: 23px;
}
ol li a:hover{
  background-color:#000;
  color: #fff;  
}

ol li.active a{
  background-color: #fff;
  color: #000;  
}






.middle{
  position: absolute;
  top: 80%;
  transform: translateY(-50%);
  width: 100%;
  text-align: center;
}
.btn{
  display: inline-block;
  width: 70px;
  height: 70px;
  background: #f1f1f1;
  margin: 10px;
  border-radius: 30%;
  box-shadow: 0 5px 15px -5px #00000070;
  color: darkorange;
  overflow: hidden;
  position: relative;
}
.btn i{
  line-height: 70px;
  font-size: 26px;
  transition: 0.2s linear;
}
.btn:hover i{
  transform: scale(1.3);
  color: #f1f1f1;
}
.btn::before{
  content: "";
  position: absolute;
  width: 120%;
  height: 120%;
  background: darkorange;
  transform: rotate(45deg);
  left: -110%;
  top: 90%;
}
.btn:hover::before{
  animation: aaa 0.7s 1;
  top: -10%;
  left: -10%;
}
@keyframes aaa {
  0%{
    left: -110%;
    top: 90%;
  }50%{
    left: 10%;
    top: -30%;
  }100%{
    top: -10%;
    left: -10%;
  }
}





@media only screen and (max-width: 1100px){
    body {
        font-family: "Lato", sans-serif;
        transition: background-color .5s;
        background-image: url(background.jpg);
        background-size: auto;
        background-position: auto;
}



@media only screen and (max-width: 600px){
    h1{
        font-size: 35px;
    }

    p{
        font-size: 17px;
    }

    body {
  font-family: "Lato", sans-serif;
  transition: background-color .5s;
  background-image: url(background.jpg);
  background-size: auto;
  background-position: center;
    }