Try editing this example and specifying your own values, for example rgb(100, 100, 100) .

Setting color using RGBA

CSS3 has a new tool for working with color - the RGBA format. It can be called an evolution of the RGB model, but with the addition of one new channel - the A or alpha channel. This channel sets the transparency of the color. Its values ​​are set in the range from 0 to 1. A value of 0 corresponds to full transparency, 1 - full opacity (the color will be the same as it was specified in the first three RGB channels), and intermediate values ​​like 0.4 or 0.6 - translucency to varying degrees.

Example code.

Here's how it will work:

This code is visually similar to the following, which uses the RGB model to specify a color value:

Here is his result:

An alpha channel value equal to zero makes any color invisible - absolutely transparent; a value equal to one translates the color in the RGB code without changes. The rgba(255,0,0,1.0) property shows the color red rgb(255, 0, 0) .

By hexadecimal value (HEX code)

In everyday life, we use the decimal counting system. Its origins are very simple - we have ten fingers on our hands, and counting on our fingers has been convenient in life. If the decimal system has ten digits: from 0 to 9, and the number 10 is the next digit, then the hexadecimal number system has 16 digits, and the next digit is the number 16.

To indicate color codes, ordinary decimal digits from 0 to 9 are used as hexadecimal digits, and Latin letters from A to F are used to indicate numbers from 10 to 15, that is, (0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F). For clarity, let's put this in a table:

To write hexadecimal numbers greater than F (15 in the decimal system), as in the decimal system, they also use the combination of two digits, but already hexadecimal, which is obvious. Thus, to write the decimal number 255 in hexadecimal notation, use FF notation.

The hexadecimal system is more understandable to the computer, and it processes values ​​​​set by hexadecimal value faster.

To specify a color in hexadecimal, precede the numeric value with a “#” sign, example: #FFC0CB. The value #FFC0CB itself consists of three hexadecimal digits FF, C0 and CB. The meaning of this entry is the same as setting the color in the RGB format (rgb(r, g, b)) - each hexadecimal digit in the HEX code indicates the color saturation in its channel of the RGB model.

This code will display the following elements:

And here is a picture with the result from the section "Setting colors using RGB" on this page above.

We see that the colors are identical.

A shortened notation of the HEX color code is allowed: a 6-digit number can be written as a 3-digit number. This is only valid when two digits in the color value of one channel are repeated.

That is, the following abbreviation is acceptable:

For example, the color #ff22aa can be written as #f2a, or the color #44aa22 can be written as #4a2.

Setting Color Using HSL

Appeared in CSS3 new format to indicate color.

The HSL format is an abbreviation for the English words: Hue (hue), Saturate (saturation) and Lightness (lightness).

Hue in HSL is the value of a color on a special color wheel (Figure 2) and is specified in degrees. If we draw analogies with the RGB model, then 0° corresponds to red, 120° corresponds to green, and 240° corresponds to blue.

The hue value will change in the range from 0 to 359.

The second value - saturation (Saturate) is set as a percentage. At 100% saturation, the color is as “juicy” as possible; as the saturation indicator moves towards 0%, the color becomes duller and fades into gray.

The third value, Lightness, is also set as a percentage. The higher the percentage, the brighter the color will be. The extreme values ​​of 0% and 100% will indicate black (no light) and white (overexposed) colors, respectively, and it does not matter which color from the color wheel was selected in the first channel. The optimal color brightness value is 50%.

Setting Color Using HSLA

The HSLA format is related to HSL, just as RGB is to RGBA. In the HSLA format, as in RGBA, an alpha channel is added, which is responsible for color transparency.

Color specified in HSL format is easier to read. We can say that it is intuitive. For example, the code hsl(120,60%,50%) can represent the final color if there is a picture of the HSL color wheel in memory. The same cannot be said about the RGB and HEX formats; the color code specified in these formats becomes clear only after it is visualized on the monitor.

New formats in CSS3 (HSL, HSLA and RGBA) work in browsers starting from versions: IE 9.0, Opera 10.0 Firefox 3.0. How can I make styles work on older browsers?

Somebloсk ( background-color: rgb(255,50,50); background-color: rgba(255,50,50,0.85) )

When using this code in older browsers, the background color for the .somebloсk class, although it will not use an alpha channel, will be displayed in RGB format.

Hexadecimal numbers are used to specify colors. The hexadecimal system, unlike the decimal system, is based, as its name suggests, on the number 16. The numbers will be as follows: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C , D, E, F. Numbers from 10 to 15 are replaced by Latin letters. Numbers greater than 15 in the hexadecimal system are formed by combining two numbers into one. For example, the number 255 in decimal corresponds to the number FF in hexadecimal. To avoid confusion in determining the number system, a hash symbol # is placed before the hexadecimal number, for example #666999. Each of the three colors - red, green and blue - can take values ​​from 00 to FF. Thus, the color symbol is divided into three components #rrggbb, where the first two symbols indicate the red component of the color, the middle two - green, and the last two - blue. It is allowed to use the abbreviated form #rgb, where each character should be doubled. Thus, the entry #fe0 should be regarded as #ffee00.

By name

Browsers support some colors by their name. In table 1 shows the names, hexadecimal code, RGB, HSL values ​​and description.

Using RGB

You can define color using the red, green, and blue values ​​in decimal terms. Each of the three color components takes a value from 0 to 255. It is also permissible to specify the color as a percentage, with 100% corresponding to the number 255. First, specify the rgb keyword, and then specify the color components in parentheses, separated by commas, for example rgb(255 , 128, 128) or rgb(100%, 50%, 50%).

RGBA

The RGBA format is similar in syntax to RGB, but includes an alpha channel that specifies the element's transparency. A value of 0 is fully transparent, 1 is opaque, and an intermediate value like 0.5 is semi-transparent.

RGBA was added to CSS3, so CSS code must be validated against this version. It should be noted that the CSS3 standard is still under development and some features may change. For example, a color in RGB format added to the background-color property is validated, but one added to the background property is no longer valid. At the same time, browsers quite correctly understand the color for both properties.

HSL

The name of the HSL format is derived from the combination of the first letters Hue (hue), Saturate (saturation) and Lightness (lightness). Hue is the color value on the color wheel (Fig. 1) and is given in degrees. 0° corresponds to red, 120° to green, and 240° to blue. The hue value can vary from 0 to 359.

Rice. 1. Color wheel

Saturation is the intensity of a color and is measured as a percentage from 0% to 100%. A value of 0% indicates no color and a shade of gray, 100% is the maximum value for saturation.

Lightness specifies how bright the color is and is specified as a percentage from 0% to 100%. Low values ​​make the color darker, and high values ​​make the color lighter; extreme values ​​of 0% and 100% correspond to black and white.

HSLA

The HSLA format is similar in syntax to HSL, but includes an alpha channel to specify the element's transparency. A value of 0 is fully transparent, 1 is opaque, and an intermediate value like 0.5 is semi-transparent.

RGBA, HSL, and HSLA color values ​​have been added to CSS3, so please check your code for version validity when using these formats.

HTML5 CSS2.1 CSS3 IE Cr Op Sa Fx

Warning

All lion catching methods listed on the site are theoretical and based on computational methods. The authors do not guarantee your safety when using them and disclaim any responsibility for the results. Remember, a lion is a predator and a dangerous animal!

The result of this example is shown in Fig. 2.

Rice. 2. Colors on the web page