*{
    padding: 0;
    margin: 0;
    box-sizing: border-box;
    outline: none;
    background-color: #ecf0f3;
}
.container{
    height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    background-color: #555;
}

.calculator{
    box-shadow: 6px 6px 13px #555,
                6px 6px 13px #fff;
    border-radius: 30px;
    padding: 15px;
    display: grid;
    grid-template-columns: repeat(4, 65px);            
}

input{
    grid-column: span 4;
    height: 68px;
    width: 258px;
    box-shadow: inset -6px -6px 13px #fff,
                inset -6px -6px 13px rgba(0, 0, 0, 0);
    background-color: #ecf0ec;
    border: none;
    border-radius: 32px;
    color: grey;
    text-align: end;
    margin: 40px 0px 30px 0px;
    padding: 25px;
    font-size: 35px;

}

button{
    box-shadow: inset -6px -6px 13px #fff,
                 6px 6px 13px rgba(0, 0, 0, 0);
    background-color: #ecf0ec;
    border: none;
    border-radius: 50%;
    width: 50px;
    height: 50px;
    margin: 10px;
    font-size: 15px;
    cursor: pointer;
}

.equal{
    width: 120px;
    border-radius: 42px;
    box-shadow: inset -6px -6px 13px #fff,
                 6px 6px 13px rgba(0, 0, 0, 0);
    background-color: #ecf0ec;

}