style.css

.container{
    margin: 0 auto;
    width: 540px;
}
.calc-body{
    display: flex;
    flex-direction: row;
    justify-content: space-around;
    border: 1px solid black;
    flex-wrap: wrap;
    align-items: center;
    padding: 10px;

}

.calc-body .top{
    height: 150px;
    background-color: antiquewhite;
    display: flex;
    flex-direction: column;
    justify-content: flex-start;
    align-items: center;
    
}
.calc-body .top div{
    display: inline-block;
    padding: 10px;
}
.calc-body .top input{
    text-align: center;
}
.calc-body .top button{

}

.calc-body .bottom{
    height: 150px;
    width: 250px;
    background-color: antiquewhite;
    display: flex;
    flex-direction: column;
    align-items: center;
}

.calc-body .bottom p{
    margin-top:-18px;
    height: 100px;
    width: 200px;
    border: 1px solid black;
    background-color: white;
    text-align: center;
    display: block;
    line-height: 100px;
}