HTML Цвета, цвет текста фона
Цвета HTML задаются с использованием предопределенных имен цветов, или RGB, Hex, HSL, RGBA, HSLA значений.
Названия цветов
В HTML цвет можно задать с помощью имени цвета:
Цвет фона
Можно задать цвет фона для элементов HTML:
Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat.
Пример
Цвет текста
Вы можете установить цвет текста:
Всем привет
Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat.
Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat.
Пример
Цвет границы
Вы можете установить цвет границ:
Всем привет
Всем привет
Всем привет
Example
Значения цвета
В HTML цвета также могут быть заданы с помощью значений RGB, шестнадцатеричных значений, HSL значений, RGBA значений и HSLA значений:
Так же, как название цвет «Tomato»:
Так же, как название цвета «Tomato», но 50% прозрачный:
Пример
Значение RGB
В HTML, цвет может быть указан как RGB значение, используя эту формулу:
Каждый параметр (красный, зеленый и синий) определяет интенсивность цвета между 0 и 255.
Например, RGB (255, 0, 0) отображается красным цветом, так как красный цвет устанавливается в его наивысшее значение (255), а остальные устанавливаются в 0.
Для отображения черного цвета, все параметры цвета должны быть установлены в 0, как это: RGB (0, 0, 0).
Для отображения белого цвета, все параметры цвета должны быть установлены в 255, как это: RGB (255, 255, 255).
background-color
The background-color CSS property sets the background color of an element.
Try it
Syntax
The background-color property is specified as a single <color> value.
Values
The uniform color of the background. It is rendered behind any background-image that is specified, although the color will still be visible through any transparency in the image.
Accessibility concerns
It is important to ensure that the contrast ratio between the background color and the color of the text placed over it is high enough that people experiencing low vision conditions will be able to read the content of the page.
Color contrast ratio is determined by comparing the luminance of the text and background color values. In order to meet current Web Content Accessibility Guidelines (WCAG), a ratio of 4.5:1 is required for text content and 3:1 for larger text such as headings. Large text is defined as 18.66px and bold or larger, or 24px or larger.
# Backgrounds
With CSS you can set colors, gradients, and images as the background of an element.
It is possible to specify various combinations of images, colors, and gradients, and adjust the size, positioning, and repetition (among others) of these.
# Background Color
The background-color property sets the background color of an element using a color value or through keywords, such as transparent , inherit or initial .
This can be applied to all elements, and ::first-letter / ::first-line pseudo-elements
Colors in CSS can be specified by different methods
# Color names
CSS
HTML
- The example used above is one of several ways that CSS has to represent a single color.
# Hex color codes
Hex code is used to denote RGB components of a color in base-16 hexadecimal notation. #ff0000, for example, is bright red, where the red component of the color is 256 bits (ff) and the corresponding green and blue portions of the color is 0 (00).
If both values in each of the three RGB pairings (R, G, and B) are the same, then the color code can be shortened into three characters (the first digit of each pairing). #ff0000 can be shortened to #f00 , and #ffffff can be shortened to #fff .
Hex notation is case-insensitive.
# RGB / RGBa
Another way to declare a color is to use RGB or RGBa.
RGB stands for Red, Green and Blue, and requires of three separate values between 0 and 255, put between brackets, that correspond with the decimal color values for respectively red, green and blue.
RGBa allows you to add an additional alpha parameter between 0.0 and 1.0 to define opacity.
# HSL / HSLa
Another way to declare a color is to use HSL or HSLa and is similar to RGB and RGBa.
HSL stands for hue, saturation, and lightness, and is also often called HLS:
- Hue is a degree on the color wheel (from 0 to 360).
- Saturation is a percentage between 0% and 100%.
- Lightness is also a percentage between 0% and 100%.
HSLa allows you to add an additional alpha parameter between 0.0 and 1.0 to define opacity.
# Interaction with background-image
The following statements are all equivalent:
They will all lead to the red color being shown underneath the image, where the parts of the image are transparent, or the image is not showing (perhaps as a result of background-repeat ).
Note that the following is not equivalent:
Here, the value of background overrides your background-image .
For more info on the background property, see Background Shorthand
# Background Gradients
Gradients are new image types, added in CSS3. As an image, gradients are set with the background-image
(opens new window) property, or the background shorthand.
There are two types of gradient functions, linear and radial. Each type has a non-repeating variant and a repeating variant:
- linear-gradient()
- repeating-linear-gradient()
- radial-gradient()
- repeating-radial-gradient()
# linear-gradient()
A linear-gradient has the following syntax
| Value | Meaning |
|---|---|
| <direction> | Could be an argument like to top , to bottom , to right or to left ; or an angle |
(opens new window) as 0deg , 90deg . . The angle starts from to top and rotates clockwise. Can be specified in deg
For example, this creates a linear gradient that starts from the right and transitions from red to blue
You can create a diagonal gradient by declaring both a horizontal and vertical starting position.
It is possible to specify any number of color stops in a gradient by separating them with commas. The following examples will create a gradient with 8 color stops
# radial-gradient()
| Value | Meaning |
|---|---|
| circle | Shape of gradient. Values are circle or ellipse , default is ellipse . |
| farthest-corner | Keywords describing how big the ending shape must be. Values are closest-side , farthest-side , closest-corner , farthest-corner |
| top left | Sets the position of the gradient center, in the same way as background-position . |
# Repeating gradients
Repeating gradient functions take the same arguments as the above examples, but tile the gradient across the background of the element.
| Value | Meaning |
|---|---|
| -45deg | Angle unit |
(opens new window) . The angle starts from to top and rotates clockwise. Can be specified in deg
Note that HEX, RGB, RGBa, HSL, and HSLa color codes may be used instead of color names. Color names were used for the sake of illustration. Also note that the radial-gradient syntax is much more complex than linear-gradient, and a simplified version is shown here. For a full explanation and specs, see the MDN Docs
# Background Image
The background-image property is used to specify a background image to be applied to all matched elements. By default, this image is tiled to cover the entire element, excluding margin.
To use multiple images as background-image , define comma separated url()
The images will stack according to their order with the first declared image on top of the others and so on.
| Value | Result |
|---|---|
| url(‘/path/to/image.jpg’) | Specify background image’s path(s) or an image resource specified with data URI schema (apostrophes can be omitted), separate multiples by comma |
| none | No background image |
| initial | Default value |
| inherit | Inherit parent’s value |
More CSS for Background Image
This following attributes are very useful and almost essential too.
# Background Shorthand
The background property can be used to set one or more background related properties:
| Value | Description | CSS Ver. |
|---|---|---|
| background-image | Background image to use | 1+ |
| background-color | Background color to apply | 1+ |
| background-position | Background image’s position | 1+ |
| background-size | Background image’s size | 3+ |
| background-repeat | How to repeat background image | 1+ |
| background-origin | How the background is positioned (ignored when background-attachment is fixed ) | 3+ |
| background-clip | How the background is painted relative to the content-box , border-box , or the padding-box | 3+ |
| background-attachment | How the background image behaves, whether it scrolls along with its containing block or has a fixed position within the viewport | 1+ |
| initial | Sets the property to value to default | 3+ |
| inherit | Inherits property value from parent | 2+ |
The order of the values does not matter and every value is optional
# Syntax
The syntax of the background shorthand declaration is:
# Examples
Simply setting a background-color with the red value.
Setting a background-clip to border-box and a background-color to red.
Sets a background-repeat to no-repeat, background-origin to center and a background-image to an image.
In this example, the background-color of the element would be set to green with pattern.png , if it is available, overlayed on the colour, repeating as often as necessary to fill the element. If pattern.png includes any transparency then the green colour will be visible behind it.
In this example we have a black background with an image ‘picture.png’ on top, the image does not repeat in either axis and is positioned in the top left corner. The / after the position is to be able to include the size of the background image which in this case is set as 600px width and auto for the height. This example could work well with a feature image that can fade into a solid colour.
NOTE: Use of the shorthand background property resets all previously set background property values, even if a value is not given. If you wish only to modify a background property value previously set, use a longhand property instead.
# Background Size
# General overview
(opens new window) property enables one to control the scaling of the background-image . It takes up to two values, which determine the scale/size of the resulting image in vertical and and horizontal direction. If the property is missing, its deemed auto in both width and height .
auto will keep the image’s aspect ratio, if it can be determined. The height is optional and can be considered auto . Therefore, on a 256 px × 256 px image, all the following background-size settings would yield an image with height and width of 50 px:
So if we started with the following picture (which has the mentioned size of 256 px × 256 px),
we’ll end up with a 50 px × 50 px on the user’s screen, contained in the background of our element:
One can also use percentage values to scale the image with respect of the element. The following example would yield a 200 px × 133 px drawn image:
The behaviour depends on the background-origin
# Keeping the aspect ratio
The last example in the previos section lost its original aspect ratio. The circle got into an ellipse, the square into a rectangle, the triangle into another triangle.
The length or percentage approach isn’t flexible enough to keep the aspect ratio at all times. auto doesn’t help, since you might not know which dimension of your element will be larger. However, to cover certain areas with an image (and correct aspect ratio) completely or to contain an image with correct aspect ratio completely in a background area, the values, contain and cover provide the additional functionality.
# Eggsplanation for contain and cover
Sorry for the bad pun, but we’re going to use a picture of the day by Biswarup Ganguly
(opens new window) for demonstration. Lets say that this is your screen, and the gray area is outside of your visible screen. For demonstration, We’re going to assume a 16 × 9 ratio.
We want to use the aforementioned picture of the day as a background. However, we cropped the image to 4×3 for some reason. We could set the background-size property to some fixed length, but we will focus on contain and cover . Note that I also assume that we didn’t mangle the width and/or height of body .
# contain
Scale the image, while preserving its intrinsic aspect ratio (if any), to the largest size such that both its width and its height can fit inside the background positioning area.
This makes sure that the background image is always completely contained in the background positioning area, however, there could be some empty space filled with your background-color in this case:
# cover
Scale the image, while preserving its intrinsic aspect ratio (if any), to the smallest size such that both its width and its height can completely cover the background positioning area.
This makes sure that the background image is covering everything. There will be no visible background-color , however depending on the screen’s ratio a great part of your image could be cut off:
How to Add & Change Background Color in HTML
Setting the background color of a web page or an element on the page can enable you to create unique layouts.
Take the homepage of Delish as an example. The background image of its header section is a colorful soup. To ensure readers can still see the name of the recipe, the background color of the text box is set to white. The effect is striking and easy to read.