顏色（Colors）
借助一些顏色通用類別讓顏色的表達具有意義。這也包括支持有hover狀態(tài)的樣式連接。
顏色
使用color通用類別為文字上色。如果要為連接上色，你可以使用助手中的彩色鏈接。它們具有：hover and：focus的狀態(tài)。
.text-primary
.text-secondary
.text-success
.text-danger
.text-warning
.text-info
.text-light
.text-dark
.text-body
.text-muted
.text-white
.text-black-50
.text-white-50
<p class="text-primary">.text-primary</p>
<p class="text-secondary">.text-secondary</p>
<p class="text-success">.text-success</p>
<p class="text-danger">.text-danger</p>
<p class="text-warning bg-dark">.text-warning</p>
<p class="text-info bg-dark">.text-info</p>
<p class="text-light bg-dark">.text-light</p>
<p class="text-dark">.text-dark</p>
<p class="text-body">.text-body</p>
<p class="text-muted">.text-muted</p>
<p class="text-white bg-dark">.text-white</p>
<p class="text-black-50">.text-black-50</p>
<p class="text-white-50 bg-dark">.text-white-50</p>Conveying meaning to assistive technologies
Using color to add meaning only provides a visual indication, which will not be conveyed to users of assistive
technologies – such as screen readers. Ensure that information denoted by the color is either obvious from the
content itself (e.g. the visible text), or is included through alternative means, such as additional text hidden
with the .visually-hidden class.
處理特殊性
有時候情境色彩并無法套用在其他的提取器，解決方案是用一個div包裝元素內(nèi)容，并將class套用在上面。
Sass
除了下面的Sass功能外，請考慮閱讀我們的CSS自定義屬性（aka CSS variables）中包含的顏色等內(nèi)容。
Most color utilities are generated by our theme colors, reassigned from our generic color palette
variables.
$blue: #0d6efd;
$indigo: #6610f2;
$purple: #6f42c1;
$pink: #d63384;
$red: #dc3545;
$orange: #fd7e14;
$yellow: #ffc107;
$green: #198754;
$teal: #20c997;
$cyan: #0dcaf0;
$primary: $blue;
$secondary: $gray-600;
$success: $green;
$info: $cyan;
$warning: $yellow;
$danger: $red;
$light: $gray-100;
$dark: $gray-900;
Grayscale colors are also available, but only a subset are used to generate any utilities.
$white: #fff;
$gray-100: #f8f9fa;
$gray-200: #e9ecef;
$gray-300: #dee2e6;
$gray-400: #ced4da;
$gray-500: #adb5bd;
$gray-600: #6c757d;
$gray-700: #495057;
$gray-800: #343a40;
$gray-900: #212529;
$black: #000;
Map
Theme colors are then put into a Sass map so we can loop over them to generate our utilities, component modifiers, and more.
$theme-colors: (
"primary": $primary,
"secondary": $secondary,
"success": $success,
"info": $info,
"warning": $warning,
"danger": $danger,
"light": $light,
"dark": $dark
);
Grayscale colors are also available as a Sass map. This map is not used to generate any utilities.
$grays: (
"100": $gray-100,
"200": $gray-200,
"300": $gray-300,
"400": $gray-400,
"500": $gray-500,
"600": $gray-600,
"700": $gray-700,
"800": $gray-800,
"900": $gray-900
);
Utilities API
Color utilities are declared in our utilities API in scss/_utilities.scss.
"color": (
property: color,
class: text,
values: map-merge(
$theme-colors,
(
"white": $white,
"body": $body-color,
"muted": $text-muted,
"black-50": rgba($black, .5),
"white-50": rgba($white, .5),
"reset": inherit,
)
)
),