.all{
    display:flex;
    height : 97vh;
    flex-direction: column;
}
.top{
    flex:2
}
.middle{
    flex:4;
}
.bottom{
    flex:2;
}
h1 {
    font-size:6em;
    text-align: center;
    font-family : "Born Ready Slanted"
}  
#content1{
    text-align: center;
    font-size:0.8em;
}
#content2{
    text-align: center;
    font-size:2em;
}
#start_btn{ 
    font-size: 30px;
    margin-left: 20px;
    margin-right : 20px;
    height : 60px;
} 
#btn_group button{ 
    border: 1px solid #4e73df; 
    background-color: rgba(0,0,0,0); 
    color: white; 
    background-color: #4e73df;
    padding: 5px; 
    display: table;
    margin-left: auto; 
    margin-right: auto;
    margin-top: 60px;
    padding-left: 50px;
    padding-right: 50px;
}
#btn_group button:hover{
    color:#4e73df; 
    background-color: white;
}
.centered { 
    display: table; margin-left: auto; 
    margin-right: auto;
}