Exploring Colors in CSS

After learning how to select HTML elements, it is time for us to talk about what you can do with them.

To get started, let's discuss how to change their colors. As we've seen previously, after you've selected a <p> element, you can change the text color by specifying a color property.

css

1p {
2  color: red;
3}

Or change the element's background color using the background-color property:

css

1p {
2  background-color: darkorange;
3}

The color property accepts descriptive words such as red, darkorange, and many more.

However, there are countless different colors in the world, and not all of them can be described with simple words. That is why CSS offers more accurate ways of specifying colors, including RGB, HEX, and HSL.

RGB color

RGB stands for Red, Green, and Blue. They are the fundamental colors in computer science, and when mixed together, they can create every color in the world. The RGB color is defined with the function rgb():

text

1rgb(<red>, <green>, <blue>)

The parameters red, green, and blue define the intensity of each color, using integer values between 0 and 255. 0 is the weakest, and 255 is the strongest. For example, the following example is the same as color: red;.

css

1p {
2  color: rgb(255, 0, 0);
3}

If you mix the colors together, you will be able to create all kinds of different colors.

css

1p {
2  color: rgb(168, 189, 45);
3}

It is recommended that you use VSCode to help you find the desired color because it is difficult to imagine the resulting color just from the numbers.

There is also a sibling function called rgba(), which takes an extra parameter.

css

1p {
2  color: rgba(<red>, <green>, <blue>, <alpha>);
3}

The last parameter, alpha, defines the transparency of the element. It accepts values from 0 to 1. 0 being completely transparent, and 1 being completely solid.

css

1p {
2  color: rgba(167, 189, 45, 0.408);
3}

HEX color

HEX colors are specified with a hexadecimal number like this:

text

1#rrggbb

The hex color code always starts with a #, and it is essentially a shorthand for the rgb() formula. Each variable, rr, gg, and bb, accepts a hex value from 00 to ff, corresponding to decimal numbers from 0 to 255. For example:

css

1p {
2  color: #ff0000;
3}

This example is the same as color: rgb(255, 0, 0); and color: red;.

Similarly, you can specify an alpha value to control the transparency of the element.

text

1#rrggbbaa

aa also takes values from 00 to ff, which are remapped to decimal values between 0 and 1.

css

1p {
2  color: #a7bd2d68;
3}

This example is the same as rgba(167, 189, 45, 0.408). You can verify that with this tool.

HSL color

If you are familiar with graphical design or some other related fields, you probably already know this color model. HSL takes three variables:

text

1hsl(<hue>, <saturation>, <lightness>)

hue is the degree on a color wheel, from 0 to 360. A color wheel looks like this:

Notice that this wheel has no black, white, or gray. That is the job for the parameters saturation and lightness.

saturation takes a percentage value, from 0 to 100, which determines how much gray should be added to the original color. 0 means the color is completely gray, and 100 means no gray is added.

lightness is also a percentage value, which determines how much black or white is added to the original color.

Lastly, hsla() is a similar formula that allows you to define an alpha value, which controls the transparency of the element.

text

1hsla(hue, saturation, lightness, alpha)

css

1p {
2  color: hsla(69, 62%, 46%, 0.408);
3}

This example is the same as #a7bd2d68 and rgba(167, 189, 45, 0.408).

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