css color: introduction to different definitions of color in css

Color is widely used in CSS, whether it is text color, background color, gradient, shadow, border... all require a method of defining color, and each color definition method has its own advantages and disadvantages. This article will share with you the different definitions of color in CSS.

The color attribute is very simple to define the color of text. More importantly, the definition of color can use different types of color units. (Recommended course: css video tutorial)

Color Name

CSS provides more than 140 color names, starting from the most basic Colors are some richer colors can be said to be colorful.

body{ color: black;}
a{ color: orange;}

The above example is defined with specific color names, but because color names are difficult to remember, and maybe you want a very specific color, the color name may not be easy to use, Let's take a look at other ways to define colors

RGB

Computer monitors, TVs, and mobile phones all use the RGB color model to display colors. Basically, every color is defined by a combination of red, green, and blue. There are 256 possible values ​​for red, green or blue. Since computers start counting at 0 (zero), the maximum value is 255.

Considering that color is the result of the combination of red, green and blue, and since each of these 3 colors has 256 possible values, 256 * 256 * 256 = 16,777,216 colors can be used .

Because the RGB model is directly related to the way colors are physically rendered, it has become a CSS color unit.

For example, you could define red as 219 red, 78 green, and 68 blue:

a{ color: rgb(219, 78, 68);}

Black is not red, green, or blue:

body{ color: rgb(0, 0, 0);}

in the spectrum On the other side, white is the full amount of each red, green and blue:

body{ color: rgb(255, 255, 255);}

RGBA

rgba color unit is rgb, which is the alpha we added Value (ranging from 0 to 1, in decimal values) that defines what the color transparency is:

body{ color: rgba(0, 0, 0, 0.8);}

A slightly transparent black.

The purpose of color transparency is to blend with the background, so it looks slightly different depending on the context. It's especially useful for background colors.

HSL and HSLA

HSL is another way to define colors. Think of it like a color wheel.

You can define it this way: Instead of combining colors as red, green and blue.

Hue values ​​range from 0 to 360, limiting them to specific colors.

Saturation is a percentage, ranging from 0% to 100%, that defines how dark or light you want the color to be.

Brightness is a percentage, ranging from 0% to 100%, that defines how bright you want the color to be.

Similarly, you can define it this way in HSL:

a{ color: hsl(4, 68%, 56%);}

4 means red 68% means red is very prominent 56% means it is between black and white

body{ color: hsla(4, 68%, 56%, 0.5);}

Hex

Treat 0-9 numbers and AF letters as symbols.

Humans use decimal. We have 10 symbols to form numbers.

In hexadecimal, we have 16 symbols to form numbers. Since 0-9 are not enough symbols, we also use A to F. It starts from scratch. So:

4The number in hexadecimal is 4

12The number in hexadecimal is C

16The number in hexadecimal is 10 because in After running out of symbols (last symbol F) add a second symbol on the left and increment (0 to 1) while the symbol on the right starts from (F to 0)

Do I have to remember this?

not at all! An explanation of how hexadecimal values ​​work is provided here. The most important thing to remember is that there are 16 hexadecimal symbols.

Just like RGB, hexadecimal color values ​​are combinations of red, green and blue, each of them is represented as a hexadecimal value such as DB red, 4E green and 44 blue color.

Because there can only be 2 symbols for red, green or blue, their possible values ​​are 16 * 16 = 256, which reflects the RGB color units!

Why not use RGB?

Generally, when choosing colors, don't write them directly. You can use the color picker or copy/paste it from Photoshop or choose a palette somewhere.

Hex values ​​are easier to copy and paste because they only contain 6 characters.

It's easier to paste a single field than 3 separate fields.

In CSS, you just prepend the hash with the hexadecimal color value #.

Which one to choose?

If you don't plan on using any transparent colors, stick with hex values ​​as they are easier to copy/paste and don't take up as much space in your code.

If you want some transparency, convert the color from hex to rgba and then use rgba color units.

If you want to use colors directly in the browser, you can use hsl.

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