0
0
mirror of https://github.com/twbs/bootstrap.git synced 2024-12-05 17:24:20 +01:00
Bootstrap/site/content/docs/5.0/utilities/background.md

79 lines
3.1 KiB
Markdown
Raw Normal View History

---
layout: docs
title: Background
description: Convey meaning through `background-color` and add decoration with gradients.
group: utilities
toc: true
---
## Background color
Similar to the contextual text color classes, set the background of an element to any contextual class. Background utilities **do not set `color`**, so in some cases you'll want to use `.text-*` [color utilities]({{< docsref "/utilities/colors" >}}).
{{< example >}}
{{< colors.inline >}}
{{- range (index $.Site.Data "theme-colors") }}
<div class="p-3 mb-2 bg-{{ .name }}{{ if .contrast_color }} text-{{ .contrast_color }}{{ else }} text-white{{ end }}">.bg-{{ .name }}</div>
{{- end -}}
{{< /colors.inline >}}
<div class="p-3 mb-2 bg-body text-dark">.bg-body</div>
<div class="p-3 mb-2 bg-white text-dark">.bg-white</div>
<div class="p-3 mb-2 bg-transparent text-dark">.bg-transparent</div>
{{< /example >}}
## Background gradient
By adding a `.bg-gradient` class, a linear gradient is added as background image to the backgrounds. This gradient starts with a semi-transparent white which fades out to the bottom.
Do you need a gradient in your custom CSS? Just add `background-image: var(--bs-gradient);`.
{{< markdown >}}
{{< colors.inline >}}
{{- range (index $.Site.Data "theme-colors") }}
<div class="p-3 mb-2 bg-{{ .name }} bg-gradient{{ with .contrast_color }} text-{{ . }}{{ else }} text-white{{ end }}">.bg-{{ .name }}.bg-gradient</div>
{{- end -}}
{{< /colors.inline >}}
{{< /markdown >}}
## Sass
In addition to the following Sass functionality, consider reading about our included [CSS custom properties]({{< docsref "/customize/css-variables" >}}) (aka CSS variables) for colors and more.
### Variables
Most `background-color` utilities are generated by our theme colors, reassigned from our generic color palette variables.
{{< scss-docs name="color-variables" file="scss/_variables.scss" >}}
{{< scss-docs name="theme-color-variables" file="scss/_variables.scss" >}}
{{< scss-docs name="variable-gradient" file="scss/_variables.scss" >}}
Grayscale colors are also available, but only a subset are used to generate any utilities.
{{< scss-docs name="gray-color-variables" file="scss/_variables.scss" >}}
### Map
Theme colors are then put into a Sass map so we can loop over them to generate our utilities, component modifiers, and more.
{{< scss-docs name="theme-colors-map" file="scss/_variables.scss" >}}
Grayscale colors are also available as a Sass map. **This map is not used to generate any utilities.**
{{< scss-docs name="gray-colors-map" file="scss/_variables.scss" >}}
### Mixins
**No mixins are used to generate our background utilities**, but we do have some additional mixins for other situations where you'd like to create your own gradients.
{{< scss-docs name="gradient-bg-mixin" file="scss/mixins/_gradients.scss" >}}
{{< scss-docs name="gradient-mixins" file="scss/mixins/_gradients.scss" >}}
### Utilities API
Background utilities are declared in our utilities API in `scss/_utilities.scss`. [Learn how to use the utilities API.]({{< docsref "/utilities/api#using-the-api" >}})
{{< scss-docs name="utils-bg-color" file="scss/_utilities.scss" >}}