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205 lines
6.5 KiB
Markdown
205 lines
6.5 KiB
Markdown
---
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layout: docs
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title: Breakpoints
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description: Breakpoints are the triggers in Bootstrap for how your layout responsive changes across device or viewport sizes.
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group: layout
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aliases: "/docs/5.0/layout/"
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toc: true
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---
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## Core concepts
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- **Breakpoints are the building blocks of responsive design.** Use them to control when your layout can be adapted at a particular viewport or device size.
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- **Use media queries to architect your CSS by breakpoint.** Media queries are a feature of CSS that allow you to conditionally apply styles based on a set of browser and operating system parameters. We most commonly use `min-width` in our media queries.
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- **Mobile first, responsive design is the goal.** Bootstrap's CSS aims to apply the bare minimum of styles to make a layout work at the smallest breakpoint, and then layers on styles to adjust that design for larger devices. This optimizes your CSS, improves rendering time, and provides a great experience for your visitors.
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## Available breakpoints
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Bootstrap includes six default breakpoints, sometimes referred to as _grid tiers_, for building responsively. These breakpoints can be customized if you're using our source Sass files.
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<table class="table">
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<thead>
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<tr>
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<th>Breakpoint</th>
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<th>Class infix</th>
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<th>Dimensions</th>
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</tr>
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</thead>
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<tbody>
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<tr>
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<td>X-Small</td>
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<td><em>None</em></td>
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<td><576px</td>
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</tr>
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<tr>
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<td>Small</td>
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<td><code>sm</code></td>
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<td>≥576px</td>
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</tr>
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<tr>
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<td>Medium</td>
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<td><code>md</code></td>
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<td>≥768px</td>
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</tr>
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<tr>
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<td>Large</td>
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<td><code>lg</code></td>
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<td>≥992px</td>
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</tr>
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<tr>
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<td>Extra large</td>
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<td><code>xl</code></td>
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<td>≥1200px</td>
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</tr>
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<tr>
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<td>Extra extra large</td>
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<td><code>xxl</code></td>
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<td>≥1400px</td>
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</tr>
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</tbody>
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</table>
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Each breakpoint was chosen to comfortably hold containers whose widths are multiples of 12. Breakpoints are also representative of a subset of common device sizes and viewport dimensions—they don't specifically target every use case or device. Instead, the ranges provide a strong and consistent foundation to build on for nearly any device.
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These breakpoints are customizable via Sass—you'll find them in a Sass map in our `_variables.scss` stylesheet.
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{{< scss-docs name="grid-breakpoints" file="scss/_variables.scss" >}}
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For more information and examples on how to modify our Sass maps and variables, please refer to [the Sass section of the Grid documentation]({{< docsref "/layout/grid#sass" >}}).
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## Media queries
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Since Bootstrap is developed to be mobile first, we use a handful of [media queries](https://developer.mozilla.org/en-US/docs/Web/CSS/Media_Queries/Using_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.
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### Min-width
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Bootstrap primarily uses the following media query ranges—or breakpoints—in our source Sass files for our layout, grid system, and components.
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```scss
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// Source mixins
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// No media query necessary for xs breakpoint as it's effectively `@media (min-width: 0) { ... }`
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@include media-breakpoint-up(sm) { ... }
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@include media-breakpoint-up(md) { ... }
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@include media-breakpoint-up(lg) { ... }
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@include media-breakpoint-up(xl) { ... }
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@include media-breakpoint-up(xxl) { ... }
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// Usage
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// Example: Hide starting at `min-width: 0`, and then show at the `sm` breakpoint
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.custom-class {
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display: none;
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}
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@include media-breakpoint-up(sm) {
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.custom-class {
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display: block;
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}
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}
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```
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These Sass mixins translate in our compiled CSS using the values declared in our Sass variables. For example:
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```scss
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// X-Small devices (portrait phones, less than 576px)
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// No media query for `xs` since this is the default in Bootstrap
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// Small devices (landscape phones, 576px and up)
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@media (min-width: 576px) { ... }
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// Medium devices (tablets, 768px and up)
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@media (min-width: 768px) { ... }
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// Large devices (desktops, 992px and up)
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@media (min-width: 992px) { ... }
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// X-Large devices (large desktops, 1200px and up)
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@media (min-width: 1200px) { ... }
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// XX-Large devices (larger desktops, 1400px and up)
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@media (min-width: 1400px) { ... }
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```
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### Max-width
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We occasionally use media queries that go in the other direction (the given screen size *or smaller*):
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```scss
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// No media query necessary for xs breakpoint as it's effectively `@media (max-width: 0) { ... }`
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@include media-breakpoint-down(sm) { ... }
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@include media-breakpoint-down(md) { ... }
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@include media-breakpoint-down(lg) { ... }
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@include media-breakpoint-down(xl) { ... }
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@include media-breakpoint-down(xxl) { ... }
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// Example: Style from medium breakpoint and down
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@include media-breakpoint-down(md) {
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.custom-class {
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display: block;
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}
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}
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```
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These mixins take those declared breakpoints, subtract `.02px` from them, and use them as our `max-width` values. For example:
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```scss
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// X-Small devices (portrait phones, less than 576px)
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@media (max-width: 575.98px) { ... }
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// Small devices (landscape phones, less than 768px)
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@media (max-width: 767.98px) { ... }
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// Medium devices (tablets, less than 992px)
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@media (max-width: 991.98px) { ... }
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// Large devices (desktops, less than 1200px)
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@media (max-width: 1199.98px) { ... }
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// X-Large devices (large desktops, less than 1400px)
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@media (max-width: 1399.98px) { ... }
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// XX-Large devices (larger desktops)
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// No media query since the xxl breakpoint has no upper bound on its width
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```
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{{< callout warning >}}
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{{< partial "callout-info-mediaqueries-breakpoints.md" >}}
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{{< /callout >}}
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### Single breakpoint
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There are also media queries and mixins for targeting a single segment of screen sizes using the minimum and maximum breakpoint widths.
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```scss
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@include media-breakpoint-only(xs) { ... }
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@include media-breakpoint-only(sm) { ... }
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@include media-breakpoint-only(md) { ... }
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@include media-breakpoint-only(lg) { ... }
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@include media-breakpoint-only(xl) { ... }
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@include media-breakpoint-only(xxl) { ... }
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```
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For example the `@include media-breakpoint-only(md) { ... }` will result in :
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```scss
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@media (min-width: 768px) and (max-width: 991.98px) { ... }
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```
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### Between breakpoints
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Similarly, media queries may span multiple breakpoint widths:
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```scss
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@include media-breakpoint-between(md, xl) { ... }
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```
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Which results in:
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```scss
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// Example
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// Apply styles starting from medium devices and up to extra large devices
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@media (min-width: 768px) and (max-width: 1199.98px) { ... }
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```
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