style.css

*{
  margin:0;
  padding:0;
}

#header-img{
  height:30px;
  
}
header{
  display:flex;
  position:fixed;
  background-color:#5F9EA0;
 max-width:100000px;
  width:100%;
  height:100px;
 overflow:hidden;
  top:0;
  z-index:2;
  
}

.nav-link{
  font-size:20px;
  color: white;
  text-decoration:none;
  padding:30px;
 
}
#dom{
  widht:500px;
  height:300px;
  margin-bottom:200px;
  text-align: center;
  margin:auto;
  margin-top:200px;
  position:relative;
}
#email{
  width:250px;
  margin-top:10px;
  height:20px;
}
#submit{
  width:200px;
  margin-top:15px;
  height:30px;
  background-color:yellow;
    font-weight: bold;
}
#how{
  width:200px;
  margin:auto;
  margin-top:40px;
}
@media only screen and (max-width: 700px){
  #header{
    display:flex;
   flex-direction:column;
    height:200px;
    padding:0px;
    margin:0px;
    width:100%;
  }
  #nav-bar{
    display:flex;
    flex-direction:column;
    margin:0px;
    padding:0px;
  }
  .nav-link{
    padding:10px;
    text-align: center;
  }
  #dom{
    margin-top:300px;
  }
  
}