style.css

html {
    /*color: white;*/
    /*background-color: rgb(50, 50, 50);*/
    font-family: Source Sans Pro,ui-sans-serif,system-ui,-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Helvetica Neue,Arial,Noto Sans,sans-serif,Apple Color Emoji,Segoe UI Emoji,Segoe UI Symbol,Noto Color Emoji;
    line-height: 1.5;
}

body {
    display: flex;
    align-items: center;
    flex-direction: column;
}

button {
    height: 90px;
    width: 200px;
    margin-top: 20px;
    cursor: pointer;
    background-color: rgb(220, 220, 240);
    border: none;
    border-radius: 10px;
    border-bottom: 3px solid rgb(200, 200, 220);
    border-right: 3px solid rgb(200, 200, 220);
    transition: all 0.2s ease;
}

button:hover {
    background-color: rgb(240, 220, 220);
    border-bottom: 3px solid rgb(220, 200, 200);
    border-right: 3px solid rgb(220, 200, 200);
    transition: all 0.2s ease;
}

.graphs {
    margin: 20px;
    display: flex;
    flex-direction: row;
    justify-content: center;
    width: 100%;
}

.option-div {
    border-radius: 10px;
    border-color: rgb(180, 180, 200);
    border-style: solid;
    border-width: 2px 4px 4px 2px;
    margin: 14px 0;
    padding: 5px;
}

.option-div > div {
    margin-left: 20px;
}

.warning-div {
    background-color: rgb(255, 230, 164);
    border-radius: 10px;
    border-bottom: 3px solid rgb(235, 210, 144);
    border-right: 3px solid rgb(235, 210, 144);
    margin: 10px;
    padding: 20px;
}

.submit {
    margin-bottom: 50px;
}

.graphs > div {
    margin: 20px;
    width: 300px;
    padding: 30px 40px;
    background-color: rgb(220, 220, 240);
    border-bottom: 3px solid rgb(200, 200, 220);
    border-right: 3px solid rgb(200, 200, 220);
    border-radius: 10px;
    line-height: 30px;
}

.graphs > div > h3 {
    font-weight: 400;
    text-decoration: underline;
}

.lds-ripple {
    display: inline-block;
    position: relative;
    width: 80px;
    height: 80px;
}
.lds-ripple div {
    position: absolute;
    border: 4px solid #000;
    opacity: 1;
    border-radius: 50%;
    animation: lds-ripple 1s cubic-bezier(0, 0.2, 0.8, 1) infinite;
}

.lds-ripple .dark-theme div {
    border: 4px solid #fff;
}
.lds-ripple div:nth-child(2) {
    animation-delay: -0.5s;
}
@keyframes lds-ripple {
    0% {
        top: 36px;
        left: 36px;
        width: 0;
        height: 0;
        opacity: 0;
    }
    4.9% {
        top: 36px;
        left: 36px;
        width: 0;
        height: 0;
        opacity: 0;
    }
    5% {
        top: 36px;
        left: 36px;
        width: 0;
        height: 0;
        opacity: 1;
    }
    100% {
        top: 0px;
        left: 0px;
        width: 72px;
        height: 72px;
        opacity: 0;
    }
}