*{
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    background-color: #ecf0f3;
    font-family: sans-serif;
    outline: none;
}
.con{
height: 100vh;
display: flex;
justify-content: center;
align-items: center;
}
.cal{
    background-color: #ecf0f3;
    padding: 15px;
    border-radius: 30px;
    box-shadow: inset 5px 5px 12px #fff,
                      5px 5px 12px rgba(0, 0, 0, .17);
    display: grid; 
    grid-template-columns: repeat(4,65px);                 
}
input{
    grid-column: span 4;
    height: 70px;
    width: 260px;
    background-color: #ecf0f3;
    box-shadow: inset -5px -5px 12px #fff,
                inset 5px 5px 12px rgba(0, 0, 0, .16);
    border: none;
    border-radius: 30px;       
    color: rgb(70, 70, 70);     
    font-size: 48px;
    text-align: end;
    margin: auto;
    margin-top: 40px;
    margin-bottom: 30px;
    padding: 20px;
}
button{
    height: 48px;
    width: 48px;
    background-color: #ecf0f3;
    box-shadow: -5px -5px 12px #fff,
                 5px  5px 12px rgba(0, 0, 0, .17);
    border: none;
    border-radius: 50%;  
    margin: 8px; 
    font-size: 16px;         
}
.equal{
    width: 115px;
    border-radius: 40px;
    background-color: #ecf0f3;
    box-shadow: -5px -5px 12px #fff,
                 5px  5px 12px rgba(0, 0, 0, .17);
}