Trosolwg

Cydrannau ac opsiynau ar gyfer gosod eich prosiect Bootstrap, gan gynnwys cynwysyddion lapio, system grid pwerus, gwrthrych cyfryngau hyblyg, a dosbarthiadau cyfleustodau ymatebol.

Cynwysyddion

Cynhwysyddion yw'r elfen gosodiad mwyaf sylfaenol yn Bootstrap ac mae eu hangen wrth ddefnyddio ein system grid rhagosodedig . Defnyddir cynwysyddion i gynnwys, padio, ac (weithiau) canoli'r cynnwys sydd ynddynt. Er y gellir nythu cynwysyddion, nid oes angen cynhwysydd nythu ar y rhan fwyaf o gynlluniau.

Daw Bootstrap gyda thri chynhwysydd gwahanol:

• .container, sy'n gosod max-widthym mhob torbwynt ymatebol
• .container-fluid, sydd width: 100%o gwbl yn dorbwyntiau
• .container-{breakpoint}, sef width: 100%tan y torbwynt penodedig

Mae'r tabl isod yn dangos sut mae pob cynhwysydd yn max-widthcymharu â'r gwreiddiol .containerac .container-fluidar draws pob torbwynt.

Eu gweld ar waith a'u cymharu yn ein hesiampl Grid .

I gyd mewn un

Mae ein .containerdosbarth rhagosodedig yn gynhwysydd ymatebol, lled sefydlog, sy'n golygu ei max-widthnewidiadau ym mhob torbwynt.

<div class="container">
  <!-- Content here -->
</div>

Hylif

Use .container-fluid for a full width container, spanning the entire width of the viewport.

<div class="container-fluid">
  ...
</div>

Responsive

Responsive containers are new in Bootstrap v4.4. They allow you to specify a class that is 100% wide until the specified breakpoint is reached, after which we apply max-widths for each of the higher breakpoints. For example, .container-sm is 100% wide to start until the sm breakpoint is reached, where it will scale up with md, lg, and xl.

<div class="container-sm">100% wide until small breakpoint</div>
<div class="container-md">100% wide until medium breakpoint</div>
<div class="container-lg">100% wide until large breakpoint</div>
<div class="container-xl">100% wide until extra large breakpoint</div>

Responsive breakpoints

Since Bootstrap is developed to be mobile first, we use a handful of media queries to create sensible breakpoints for our layouts and interfaces. These breakpoints are mostly based on minimum viewport widths and allow us to scale up elements as the viewport changes.

Bootstrap primarily uses the following media query ranges—or breakpoints—in our source Sass files for our layout, grid system, and components.

// Extra small devices (portrait phones, less than 576px)
// No media query for `xs` since this is the default in Bootstrap

// Small devices (landscape phones, 576px and up)
@media (min-width: 576px) { ... }

// Medium devices (tablets, 768px and up)
@media (min-width: 768px) { ... }

// Large devices (desktops, 992px and up)
@media (min-width: 992px) { ... }

// Extra large devices (large desktops, 1200px and up)
@media (min-width: 1200px) { ... }

Since we write our source CSS in Sass, all our media queries are available via Sass mixins:

// No media query necessary for xs breakpoint as it's effectively `@media (min-width: 0) { ... }`
@include media-breakpoint-up(sm) { ... }
@include media-breakpoint-up(md) { ... }
@include media-breakpoint-up(lg) { ... }
@include media-breakpoint-up(xl) { ... }

// Example: Hide starting at `min-width: 0`, and then show at the `sm` breakpoint
.custom-class {
  display: none;
}
@include media-breakpoint-up(sm) {
  .custom-class {
    display: block;
  }
}

We occasionally use media queries that go in the other direction (the given screen size or smaller):

// Extra small devices (portrait phones, less than 576px)
@media (max-width: 575.98px) { ... }

// Small devices (landscape phones, less than 768px)
@media (max-width: 767.98px) { ... }

// Medium devices (tablets, less than 992px)
@media (max-width: 991.98px) { ... }

// Large devices (desktops, less than 1200px)
@media (max-width: 1199.98px) { ... }

// Extra large devices (large desktops)
// No media query since the extra-large breakpoint has no upper bound on its width

Once again, these media queries are also available via Sass mixins:

@include media-breakpoint-down(xs) { ... }
@include media-breakpoint-down(sm) { ... }
@include media-breakpoint-down(md) { ... }
@include media-breakpoint-down(lg) { ... }
// No media query necessary for xl breakpoint as it has no upper bound on its width

// Example: Style from medium breakpoint and down
@include media-breakpoint-down(md) {
  .custom-class {
    display: block;
  }
}

There are also media queries and mixins for targeting a single segment of screen sizes using the minimum and maximum breakpoint widths.

// Extra small devices (portrait phones, less than 576px)
@media (max-width: 575.98px) { ... }

// Small devices (landscape phones, 576px and up)
@media (min-width: 576px) and (max-width: 767.98px) { ... }

// Medium devices (tablets, 768px and up)
@media (min-width: 768px) and (max-width: 991.98px) { ... }

// Large devices (desktops, 992px and up)
@media (min-width: 992px) and (max-width: 1199.98px) { ... }

// Extra large devices (large desktops, 1200px and up)
@media (min-width: 1200px) { ... }

These media queries are also available via Sass mixins:

@include media-breakpoint-only(xs) { ... }
@include media-breakpoint-only(sm) { ... }
@include media-breakpoint-only(md) { ... }
@include media-breakpoint-only(lg) { ... }
@include media-breakpoint-only(xl) { ... }

Similarly, media queries may span multiple breakpoint widths:

// Example
// Apply styles starting from medium devices and up to extra large devices
@media (min-width: 768px) and (max-width: 1199.98px) { ... }

The Sass mixin for targeting the same screen size range would be:

@include media-breakpoint-between(md, xl) { ... }

Z-index

Several Bootstrap components utilize z-index, the CSS property that helps control layout by providing a third axis to arrange content. We utilize a default z-index scale in Bootstrap that’s been designed to properly layer navigation, tooltips and popovers, modals, and more.

These higher values start at an arbitrary number, high and specific enough to ideally avoid conflicts. We need a standard set of these across our layered components—tooltips, popovers, navbars, dropdowns, modals—so we can be reasonably consistent in the behaviors. There’s no reason we couldn’t have used 100+ or 500+.

We don’t encourage customization of these individual values; should you change one, you likely need to change them all.

$zindex-dropdown:          1000 !default;
$zindex-sticky:            1020 !default;
$zindex-fixed:             1030 !default;
$zindex-modal-backdrop:    1040 !default;
$zindex-modal:             1050 !default;
$zindex-popover:           1060 !default;
$zindex-tooltip:           1070 !default;

To handle overlapping borders within components (e.g., buttons and inputs in input groups), we use low single digit z-index values of 1, 2, and 3 for default, hover, and active states. On hover/focus/active, we bring a particular element to the forefront with a higher z-index value to show their border over the sibling elements.