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Overview

Components and options for laying out your Boosted project, including wrapping containers, a powerful grid system, a flexible media object, and responsive utility classes.

Containers

Containers are the most basic layout element in Boosted and are required when using our default grid system. Containers are used to contain, pad, and (sometimes) center the content within them. While containers can be nested, most layouts do not require a nested container.

Boosted comes with three different containers:

.container, which sets a max-width at each responsive breakpoint
.container-fluid, which is width: 100% at all breakpoints
.container-{breakpoint}, which is width: 100% until the specified breakpoint

The table below illustrates how each container’s max-width compares to the original .container and .container-fluid across each breakpoint.

See them in action and compare them in our Grid example.

	Extra small <480px	Small ≥480px	Medium ≥768px	Large ≥1024px	Extra large ≥1280px	Extra Extra large ≥1440px
`.container`	312px	468px	744px	960px	1200px	1320px
`.container-sm`	100%	468px	744px	960px	1200px	1320px
`.container-md`	100%	100%	744px	960px	1200px	1320px
`.container-lg`	100%	100%	100%	960px	1200px	1320px
`.container-xl`	100%	100%	100%	100%	1200px	1320px
`.container-xxl`	100%	100%	100%	100%	100%	1320px
`.container-fluid`	100%	100%	100%	100%	100%	100%

All-in-one

Our default .container class is a responsive, fixed-width container, meaning its max-width changes at each breakpoint.

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

Fluid

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 Boosted 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, xl and xxl.

<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>
<div class="container-xxl">100% wide until extra extra large breakpoint</div>

Responsive breakpoints

Since Boosted 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.

Boosted 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 480px)
// No media query for `xs` since this is the default in Boosted

// Small devices (landscape phones, 480px and up)
@media (min-width: 480px) { ... }

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

// Large devices (desktops, 1024px and up)
@media (min-width: 1024px) { ... }

// Extra large devices (large desktops, 1280px and up)
@media (min-width: 1280px) { ... }

// Extra extra large devices (large desktops, 1440px and up)
@media (min-width: 1440px) { ... }

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) { ... }
@include media-breakpoint-up(xxl) { ... }
// 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 480px)
@media (max-width: 479.98px) { ... }

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

// Medium devices (tablets, less than 1024px)
@media (max-width: 1023.98px) { ... }

// Large devices (desktops, less than 1280px)
@media (max-width: 1279.98px) { ... }

// Extra large devices (desktops, less than 1440px)
@media (max-width: 1439.98px) { ... }

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

Note that since browsers do not currently support range context queries, we work around the limitations of min- and max- prefixes and viewports with fractional widths (which can occur under certain conditions on high-dpi devices, for instance) by using values with higher precision for these comparisons.

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) { ... }
@include media-breakpoint-down(xl) { ... }
// No media query necessary for xxl 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 480px)
@media (max-width: 479.98px) { ... }

// Small devices (landscape phones, 480px and up)
@media (min-width: 480px) and (max-width: 767.98px) { ... }

// Medium devices (tablets, 768px and up)
@media (min-width: 768px) and (max-width: 1023.98px) { ... }

// Large devices (desktops, 1024px and up)
@media (min-width: 1024px) and (max-width: 1279.98px) { ... }

// Extra large devices (desktops, 1280px and up)
@media (min-width: 1280px) and (max-width: 1439.98px) { ... }

// Extra extra large devices (large desktops, 1440px and up)
@media (min-width: 1440px) { ... }

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) { ... }
@include media-breakpoint-only(xxl) { ... }

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: 1023.98px) { ... }

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

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

Z-index

Several Boosted 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 Boosted 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.