style.css

body{
    margin: 0;
    padding: 0;
    line-height: 0.5;
    background: url(C.jpg);
}
.calci{
    width: 600px;
    padding-top: 100px;
    padding-bottom: 100px;
    position: absolute;
    top: 50%;
    left: 70%;
    transform: translate(-50%,-50%);
    transition: 0.25px;
    text-align: center;
}
#display{


   border: none;
   background: white;
   border-radius: 30px; 
   width: 250; 
   font-size: 40;
   font-family: 'DS-Digital';
   font-weight: 300;
   height: 60;
   margin-top: 1;
   border: 2px solid rgb(0, 0, 0);
   color: black;
   border: 1px solid black;
}
.btnDesign{
    width: 55;
    height: 55;
    padding-top: -1;
    font-family: sans-serif;
    font-size: 20;
    font-weight: 300;
    border-radius: 30px;
    margin: 1;
}
.operatorDesign{
    width: 55;
    height: 55;
    padding-top: -1;
    font-family: sans-serif;
    font-size: 20;
    font-weight: 300;
    border-radius: 30px;
    margin: 1;
    color: white;
    background-color: black;
    transition: 0.25px;
    cursor: pointer;
}
.color1{
    width: 112;
    height: 55;
    padding-top: -1;
    font-family: sans-serif;
    font-size: 20;
    font-weight: 300;
    border-radius: 30px;
    margin: 1;
    background-color: red;
    color: white;
}
.color2{
    width: 55;
    height: 55;
    padding-top: -1;
    font-family: sans-serif;
    font-size: 20;
    font-weight: 300;
    border-radius: 30px;
    margin: 1;
    background-color: gray;
    color: white;
}
.zero{
    width: 55;
    height: 55;
    padding-top: -1;
    font-family: sans-serif;
    font-size: 20;
    font-weight: 300;
    border-radius: 30px;
    margin: 1;
}
h1{
    color: black;
    outline: black;
    margin-top: 140px;
    margin-left: 100px;
    text-transform: uppercase;
   font-family: 'Times New Roman';
    font-weight: 700px;
    text-decoration: underline;
    font-size: 50;
}
h2{
    color: black;
    margin-top: -1px;
    margin-left: 120px;
    font-family: cursive;
    font-weight: 500px;
    text-decoration: initial;
    font-size: 20;
}
h6{
    color: black;
    margin: 360px;
    margin-top: 420px;
    margin-left: 500px;
    text-transform: initial;
    font-family: sans-serif;
    font-weight: 700px;
    text-decoration: initial;
    font-size: 18;
}