html {
    height: 100%;
}
body {
    height: 100%;
    margin: 0;
    padding: 0;
    background-size: 100% 100%;
    background-repeat: no-repeat;
    background-attachment: fixed;
    font-family: Arial, sans-serif;
}

.tabs {
    display: flex;
    justify-content: space-around;
    color: #fff;
}

.tab {
    flex: 1;
    cursor: pointer;
    text-align: center;
    display: flex;
    flex-direction: row;
    align-items: center;
    justify-content: center;
}

.buttons {
    flex-direction: column;
    justify-content: center;
    align-items: center;
    padding: 20px;
}

.flex {
    display: flex;
}

.hidden {
    display: none;
}

a.button {
    -webkit-appearance: button;
    -moz-appearance: button;
    appearance: button;
    background-color: #247bff;
    border: none;
    border-radius: 20px;
    font-size: 30px;
    font-weight: 300;     
    letter-spacing: 1px;       
    color: #fff;
    padding: 15px;
    margin: 10px;
    text-align: center;
    text-decoration: none;
    cursor: pointer;
    display: block;
    max-width: 500px;
    width: 100%;
}

a.red {
    background-color: #ac2925;
}

a.green {
    background-color: #13da86;
}

.button:hover {
    background-color: #0056b3;
}
.red:hover {
    background-color: #800000;
}

img {
    border-radius: 50%;
    padding: 5px;   
}

@media (max-width: 250px) {
    .tabs {
        flex-direction: column;
        text-align: center;
    }

    .tab {
        flex: none;
        width: 100%;
        padding: 10px;
    }
}

@media (prefers-color-scheme: dark) {
    body {
        background-color: #1e1e1e;
        background-image: linear-gradient(#171717, #1e1e1e);
    }

    .tabs {
        background-color: #2d2d2d;
    }

    .tabs .tab {
        color: #fff;
    }

    .tab.active {
        background-color: #171717;
    }

    .tab:hover {
        background-color: #555;
    }

    .tab.active:hover {
        background-color: #171717;
    }
}

@media (prefers-color-scheme: light) {
    body {
        background-image: linear-gradient(#f4f4f4, #efefef);
    }

    .tabs {
        background-color: #cacaca;
    }

    .tabs .tab {
        color: #000;
    }

    .tab.active {
        background-color: #f4f4f4;
    }

    .tab:hover {
        background-color: #dadada;
    }

    .tab.active:hover {
        background-color: #f4f4f4;
    }
}