style.css

body{
    background: rgb(98, 177, 177);
}
.container{
    width: 100vw;
    height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    flex-direction: column;
}
.box{
    width: 255px;
    min-height: 350px;
    background-color: #d4cec7;
    border: 3px solid #424040;
    border-radius: 5%;
    padding: 25px;
}
input{
    height: 30px;
    border-radius: 8px;
}
input:focus{
    border-color: blue;
}
button{
    height: 40px;
    border-radius: 8px;
    background-color: aquamarine;
    cursor: pointer;
}
button:hover{
    background-color: aqua;
}
#numbersField, #results{
    background-color: antiquewhite;
    color: #424040;
    border: 1px solid #424040;
    border-radius: 20px;
    width: 230px;
    padding-left: 15px;
    min-height: 25px;
}
#results{
    margin-top: 25px;
}
#calculate{
    margin-top: 25px;
    width: 250px;
}