/* There are a bunch of named colors. */
li:nth-child(1) { color: dodgerblue; }

/* Or you can specify a hex value. Brands love these. */
li:nth-child(2) { color: #1e90ff; }

/* Or RGB for Red, Green, Blue, if you think like a screen. */
li:nth-child(3) { color: rgb(30, 144, 255); }

/* Or Hue, Saturation, Lightness, which is more human. */
li:nth-child(4) { color: hsl(210, 100%, 56%); }

/* RGB and HSL have a fourth value, for Alpha (transparency). */
li:nth-child(5) { color: rgba(30, 144, 255, 50%); }
li:nth-child(6) { color: hsla(210, 100%, 56%, 0.5); }
/* Alpha as a percentage, 0–100%, or a decimal, 0–1. */

/* Nowadays you can “mix” colors. */
li:nth-child(7) { color: color-mix(in srgb, dodgerblue, tomato); }

li:nth-child(8) {
	color: dodgerblue;
	opacity: 0.5; /* This will affect everything, not just text! */
}

li:nth-child(9) {
	color: white;
	background-color: dodgerblue; /* Same for backgrounds! */
}

li + li { margin-block-start: 2em } /* Just for the demo. */