main.css

body {
    margin: 0;
    padding: 0;
}

div {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    overflow: hidden
}

input {
    border-radius: 10px;
    padding: 5px;
}

#mainFrame {
    width: 350px;
    margin: auto;
    text-align: left;
    border-radius: 25px;
    font-size: 20px;
    margin-top: 20px;
}

#mainFrameHeader {
    background-color: black;
    color: white;
    text-align: center;
    padding: 2px;
}

#mainFrameContent {
    background-color: white;
    padding: 10px;
    padding-bottom: 50px;
}

#calculateButtonDiv {
    display: flex;
    justify-content: center;
    align-items: center;
}

#calculateButton {
    background-color: darkred;
    color: white;
    border: none;
    padding: 10px;
    border-radius: 10px;
    font-weight: bold;
    margin: 20px;
    display: inline-block;
}

#calculateButton:hover {
    cursor: pointer;
}

#opinion {
    border-radius: 10px;
    padding: 5px;
}

#gradient {
    z-index: -1;
    position: fixed;
    top: 0;
    bottom: 0;
    width: 100vw;
    height: 100vh;
    background: linear-gradient(-45deg, #EE7752, #E73C7E, #23A6D5, #23D5AB);
    background-size: 400% 400%;
    animation: Gradient 15s ease infinite;
}

@keyframes Gradient {
    0% {
        background-position: 0% 50%
    }
    50% {
        background-position: 100% 50%
    }
    100% {
        background-position: 0% 50%
    }
}