:root {
    background-color: lightgray;
    animation: rainbow 20s linear infinite;
}

h1, h2, h3 {
    color: green;
    background-color: hotpink;
    border: 10px ridge hotpink;
}

:not(pre) > code {
    background-color: transparent;
    border: none;
}

p {
    color: yellow;
}

p:nth-of-type(2n) {
    color: red;
}

h1 {
    background-color: ;
}


@keyframes rainbow {
    from {
        background-color: red;
    }

    14% {
        background-color: darkorange;
    }

    28% {
        background-color: yellow;
    }

    42% {
        background-color: darkgreen;
    }

    56% {
        background-color: cyan;
    }

    70% {
        background-color: darkblue;
    }

    84% {
        background-color: violet;
    }

    100% {
        background-color: red;
    }
}