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diff --git a/site/content/docs/5.2/layout/breakpoints.md b/site/content/docs/5.2/layout/breakpoints.md new file mode 100644 index 0000000..e773b8f --- /dev/null +++ b/site/content/docs/5.2/layout/breakpoints.md @@ -0,0 +1,174 @@ +--- +layout: docs +title: Breakpoints +description: Breakpoints are customizable widths that determine how your responsive layout behaves across device or viewport sizes in Bootstrap. +group: layout +aliases: "/docs/5.2/layout/" +toc: true +--- + +## Core concepts + +- **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. + +- **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. + +- **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. + +## Available breakpoints + +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. + +{{< bs-table "table" >}} +| Breakpoint | Class infix | Dimensions | +| --- | --- | --- | +| Extra small | <em>None</em> |<576px | +| Small | `sm` | ≥576px | +| Medium | `md` | ≥768px | +| Large | `lg` | ≥992px | +| Extra large | `xl` | ≥1200px | +| Extra extra large | `xxl` | ≥1400px | +{{< /bs-table >}} + + +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. + +These breakpoints are customizable via Sass—you'll find them in a Sass map in our `_variables.scss` stylesheet. + +{{< scss-docs name="grid-breakpoints" file="scss/_variables.scss" >}} + +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" >}}). + +## Media queries + +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. + +### Min-width + +Bootstrap primarily uses the following media query ranges—or breakpoints—in our source Sass files for our layout, grid system, and components. + +```scss +// Source 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) { ... } +@include media-breakpoint-up(xxl) { ... } + +// Usage + +// 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; + } +} +``` + +These Sass mixins translate in our compiled CSS using the values declared in our Sass variables. For example: + +```scss +// X-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) { ... } + +// X-Large devices (large desktops, 1200px and up) +@media (min-width: 1200px) { ... } + +// XX-Large devices (larger desktops, 1400px and up) +@media (min-width: 1400px) { ... } +``` + +### Max-width + +We occasionally use media queries that go in the other direction (the given screen size *or smaller*): + +```scss +// No media query necessary for xs breakpoint as it's effectively `@media (max-width: 0) { ... }` +@include media-breakpoint-down(sm) { ... } +@include media-breakpoint-down(md) { ... } +@include media-breakpoint-down(lg) { ... } +@include media-breakpoint-down(xl) { ... } +@include media-breakpoint-down(xxl) { ... } + +// Example: Style from medium breakpoint and down +@include media-breakpoint-down(md) { + .custom-class { + display: block; + } +} +``` + +These mixins take those declared breakpoints, subtract `.02px` from them, and use them as our `max-width` values. For example: + +```scss +// `xs` returns only a ruleset and no media query +// ... { ... } + +// `sm` applies to x-small devices (portrait phones, less than 576px) +@media (max-width: 575.98px) { ... } + +// `md` applies to small devices (landscape phones, less than 768px) +@media (max-width: 767.98px) { ... } + +// `lg` applies to medium devices (tablets, less than 992px) +@media (max-width: 991.98px) { ... } + +// `xl` applies to large devices (desktops, less than 1200px) +@media (max-width: 1199.98px) { ... } + +// `xxl` applies to x-large devices (large desktops, less than 1400px) +@media (max-width: 1399.98px) { ... } +``` + +{{< callout warning >}} +{{< partial "callout-info-mediaqueries-breakpoints.md" >}} +{{< /callout >}} + +### Single breakpoint + +There are also media queries and mixins for targeting a single segment of screen sizes using the minimum and maximum breakpoint widths. + +```scss +@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) { ... } +@include media-breakpoint-only(xxl) { ... } +``` + +For example the `@include media-breakpoint-only(md) { ... }` will result in : + +```scss +@media (min-width: 768px) and (max-width: 991.98px) { ... } +``` + +### Between breakpoints + +Similarly, media queries may span multiple breakpoint widths: + +```scss +@include media-breakpoint-between(md, xl) { ... } +``` + +Which results in: + +```scss +// Example +// Apply styles starting from medium devices and up to extra large devices +@media (min-width: 768px) and (max-width: 1199.98px) { ... } +``` |