JSFiddle - React, Tailwind, and code Playground

HTML

<div>
    Letters
    <p>#aa0000</p>
    <p>#bb0000</p>
    <p>#cc0000</p>
    <p>#dd0000</p>
    <p>#ee0000</p>
    <p>#ff0000</p><!-- ff0000 -->
    Numbers
    <p>#990000</p>
    <p>#880000</p>
    <p>#770000</p>
    <p>#660000</p>
    <p>#550000</p>
    <p>#440000</p>
    <p>#330000</p>
    <p>#220000</p>
    <p>#110000</p>
</div>

CSS

*{
    border:0;
    margin:0;
    color:#fff;
    text-indent:25px;
}
div p:nth-of-type(1){
    background:#aa0000;
}
div p:nth-of-type(2){
    background:#bb0000;
}
div p:nth-of-type(3){
    background:#cc0000;
}
div p:nth-of-type(4){
    background:#dd0000;
}
div p:nth-of-type(5){
    background:#ee0000;
}
div p:nth-of-type(6){
    background:#ff0000;
}
div p:nth-of-type(7){
    background:#990000;
}
div p:nth-of-type(8){
    background:#880000;
}
div p:nth-of-type(9){
    background:#770000;
}
div p:nth-of-type(10){
    background:#660000;
}
div p:nth-of-type(11){
    background:#550000;
}
div p:nth-of-type(12){
    background:#440000;
}
div p:nth-of-type(13){
    background:#330000;
}
div p:nth-of-type(14){
    background:#220000;
}
div p:nth-of-type(15){
    background:#110000;
}