Pozadina
Prenesite značenje kroz background-colorgradijente i dodajte ukrase.
Boja pozadine
Slično kontekstualnim klasama boja teksta, postavite pozadinu elementa na bilo koju kontekstualnu klasu. Pomoćni programi za pozadinu ne postavljaju secolor , pa ćete u nekim slučajevima htjeti koristiti pomoćne programe za .text-* boje .
<div class="p-3 mb-2 bg-primary text-white">.bg-primary</div>
<div class="p-3 mb-2 bg-secondary text-white">.bg-secondary</div>
<div class="p-3 mb-2 bg-success text-white">.bg-success</div>
<div class="p-3 mb-2 bg-danger text-white">.bg-danger</div>
<div class="p-3 mb-2 bg-warning text-dark">.bg-warning</div>
<div class="p-3 mb-2 bg-info text-dark">.bg-info</div>
<div class="p-3 mb-2 bg-light text-dark">.bg-light</div>
<div class="p-3 mb-2 bg-dark text-white">.bg-dark</div>
<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>Gradijent pozadine
Dodavanjem .bg-gradientklase, linearni gradijent dodaje se kao pozadinska slika pozadini. Ovaj gradijent počinje s poluprozirnom bijelom koja blijedi prema dnu.
Trebate li gradijent u prilagođenom CSS-u? Samo dodajte background-image: var(--bs-gradient);.
Neprozirnost
Dodano u v5.1.0
Od v5.1.0, background-coloruslužni programi se generiraju sa Sass-om pomoću CSS varijabli. To omogućuje promjene boja u stvarnom vremenu bez kompilacije i promjene dinamičke alfa transparentnosti.
Kako radi
Razmotrite naš zadani .bg-successuslužni program.
.bg-success {
--bs-bg-opacity: 1;
background-color: rgba(var(--bs-success-rgb), var(--bs-bg-opacity)) !important;
}
Koristimo RGB verziju naše --bs-success(s vrijednošću 25, 135, 84) CSS varijable i dodali smo drugu CSS varijablu, --bs-bg-opacity, za alfa transparentnost (sa zadanom vrijednošću 1zahvaljujući lokalnoj CSS varijabli). To znači da je .bg-successvaša izračunata colorvrijednost svaki put kada sada koristite rgba(25, 135, 84, 1). Lokalna CSS varijabla unutar svake .bg-*klase izbjegava probleme nasljeđivanja tako da ugniježđene instance uslužnih programa nemaju automatski modificiranu alfa transparentnost.
Primjer
Da biste promijenili tu neprozirnost, nadjačajte --bs-bg-opacitypomoću prilagođenih stilova ili ugrađenih stilova.
<div class="bg-success p-2 text-white">This is default success background</div>
<div class="bg-success p-2" style="--bs-bg-opacity: .5;">This is 50% opacity success background</div>Ili odaberite neki od .bg-opacityuslužnih programa:
<div class="bg-success p-2 text-white">This is default success background</div>
<div class="bg-success p-2 text-white bg-opacity-75">This is 75% opacity success background</div>
<div class="bg-success p-2 text-dark bg-opacity-50">This is 50% opacity success background</div>
<div class="bg-success p-2 text-dark bg-opacity-25">This is 25% opacity success background</div>
<div class="bg-success p-2 text-dark bg-opacity-10">This is 10% opacity success background</div>Sass
Uz sljedeće Sass funkcije, razmislite o čitanju o našim uključenim CSS prilagođenim svojstvima (poznatim i kao CSS varijable) za boje i više.
Varijable
Većina background-coloruslužnih programa generirana je našim bojama tema, dodijeljenim iz naših generičkih varijabli palete boja.
$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;
$gradient: linear-gradient(180deg, rgba($white, .15), rgba($white, 0));
Dostupne su i sive boje, ali samo se podskup koristi za generiranje bilo kakvih pomoćnih programa.
$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;
Karta
Boje teme se zatim stavljaju u Sass mapu kako bismo mogli prelaziti preko njih kako bismo generirali svoje pomoćne programe, modifikatore komponenti i još mnogo toga.
$theme-colors: (
"primary": $primary,
"secondary": $secondary,
"success": $success,
"info": $info,
"warning": $warning,
"danger": $danger,
"light": $light,
"dark": $dark
);
Boje u sivim tonovima također su dostupne kao Sass karta. Ova se karta ne koristi za generiranje pomoćnih programa.
$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
);
RGB boje se generiraju iz zasebne Sass karte:
$theme-colors-rgb: map-loop($theme-colors, to-rgb, "$value");
A neprozirnost pozadinske boje temelji se na tome s vlastitom kartom koju koristi API uslužnih programa:
$utilities-bg: map-merge(
$utilities-colors,
(
"black": to-rgb($black),
"white": to-rgb($white),
"body": to-rgb($body-bg)
)
);
$utilities-bg-colors: map-loop($utilities-bg, rgba-css-var, "$key", "bg");
Mixins
Miksini se ne koriste za generiranje naših uslužnih programa u pozadini , ali imamo neke dodatne miksine za druge situacije u kojima biste željeli stvoriti vlastite gradijente.
@mixin gradient-bg($color: null) {
background-color: $color;
@if $enable-gradients {
background-image: var(--#{$variable-prefix}gradient);
}
}
// Horizontal gradient, from left to right
//
// Creates two color stops, start and end, by specifying a color and position for each color stop.
@mixin gradient-x($start-color: $gray-700, $end-color: $gray-800, $start-percent: 0%, $end-percent: 100%) {
background-image: linear-gradient(to right, $start-color $start-percent, $end-color $end-percent);
}
// Vertical gradient, from top to bottom
//
// Creates two color stops, start and end, by specifying a color and position for each color stop.
@mixin gradient-y($start-color: $gray-700, $end-color: $gray-800, $start-percent: null, $end-percent: null) {
background-image: linear-gradient(to bottom, $start-color $start-percent, $end-color $end-percent);
}
@mixin gradient-directional($start-color: $gray-700, $end-color: $gray-800, $deg: 45deg) {
background-image: linear-gradient($deg, $start-color, $end-color);
}
@mixin gradient-x-three-colors($start-color: $blue, $mid-color: $purple, $color-stop: 50%, $end-color: $red) {
background-image: linear-gradient(to right, $start-color, $mid-color $color-stop, $end-color);
}
@mixin gradient-y-three-colors($start-color: $blue, $mid-color: $purple, $color-stop: 50%, $end-color: $red) {
background-image: linear-gradient($start-color, $mid-color $color-stop, $end-color);
}
@mixin gradient-radial($inner-color: $gray-700, $outer-color: $gray-800) {
background-image: radial-gradient(circle, $inner-color, $outer-color);
}
@mixin gradient-striped($color: rgba($white, .15), $angle: 45deg) {
background-image: linear-gradient($angle, $color 25%, transparent 25%, transparent 50%, $color 50%, $color 75%, transparent 75%, transparent);
}
API za pomoćne programe
Pozadinski pomoćni programi navedeni su u našem API-ju za pomoćne programe u scss/_utilities.scss. Naučite kako koristiti API uslužnih programa.
"background-color": (
property: background-color,
class: bg,
local-vars: (
"bg-opacity": 1
),
values: map-merge(
$utilities-bg-colors,
(
"transparent": transparent
)
)
),
"bg-opacity": (
css-var: true,
class: bg-opacity,
values: (
10: .1,
25: .25,
50: .5,
75: .75,
100: 1
)
),