body {
    margin: 0;
    padding: 0;
   background-color: black;
     color: white;
     font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
}
html {
    border: solid 5px green;
    
}
h2 {
    text-align: center;
     padding-bottom: 1px;
     color: #84BBEF
}
#head {
     text-align: center;
     padding-bottom: 1px;
     color: #B6E94F
}
#main {
    color: #08DBFB ;
    text-align: center;
    margin: 1px;
    padding-bottom:30px;
    font-size: 60px;
    background: #F315F7
}
header {
     background: #F315F7;
     padding-bottom: 15px;
     padding-top: 1px
}
footer {
      background-color: black;
      font-size: px;
}

p {
   color: goldenrod;
   text-align: center;
   font-size: 20px;
}
button {
    margin-left: 289px;
    padding: 10px;
    background: #F31E7E;
    color: yellow;
}
#sub {
    margin-left: 4px;
    padding:10px 12px;
    background: #9066F1;
}
#run {
     margin-left: 352px;
    padding:10px 12px;
    background: #4B58EB;
    margin-top: 10px;
}
#div {
    margin-left: 4px;
    padding:10px 13px;
    background: #2462F3;
}
#mul {
    margin-left: 4px;
    padding:10px 12px;
    background: #FA5E70;

}