body {
    background-color: black;
    font-family: Arial, serif;
}

.logo {
    width: 100px;
    height: 100px;
}

.top {
    height: 50px;
    color: white;
    margin-bottom: 75px;
}

#ntrInput, #rtnInput {
    width: 98%;
    height: 40px;
    border: solid white 1px;
    border-radius: 15px;
    font-size: 32px;
    background-color: black;
    color: white;
    text-align: right;
    position: relative;
    top: -50%;
}

.keyboard1 {
    height: 420px;
    width: 325px;
    border: solid white 1px;
    margin-left: auto;
    margin-right: auto;
    margin-top: 5%;
    border-radius: 25px;
    background-color: black;
    text-align: center;
    /*1080x2106  1.95 ratio*/
}

.keyboard2 {
    height: 340px;
    width: 325px;
    border: solid white 1px;
    margin-left: auto;
    margin-right: auto;
    margin-top: 5%;
    border-radius: 25px;
    background-color: black;
    text-align: center;
    /*1080x2106  1.95 ratio*/
}

.guideline {
    height: 30px;
}

.instruction {
    font-size: 15px;
    color: white;
    text-align: center;
}

.left, .right {
    float: left;
    width: 49%;
}

@media screen and (max-width: 1000px) {
    .left, .right{
        width: 100%;
    }

    .keyboard1 {
        margin-top: 50px;
        margin-bottom: 50px;
    }

    .keyboard2 {
        margin-top: 50px;
        margin-bottom: 50px;
    }
}

/*buttons*/
button {
    display: inline-block;
    margin-top: 5px;
    width: 25%;
    height: 75px;
    border: none;
    border-radius: 50%;
    font-size: 24px;
    font-weight: bold;
    color: white;
    cursor: pointer;
}

.number {
    background-color: rgb(50, 50, 50);
}

.number:hover {
    background-color: grey;
}

.clear {
    background-color: rgb(51, 0, 9);
}

.clear:hover {
    background-color: darkmagenta;
}

.unused {
    background-color: black;
    color: black;
}

.enter {
    background-color: tan;
}

.enter:hover {
    background-color: antiquewhite;
}