Bootstrap Icons in CSS

A 100% pure CSS icon implementation of Bootstrap Icons using CSS custom properties and SVG masks.

Docs and icon gallery: https://coliff.github.io/bootstrap-icons-css/docs/

• No JavaScript, dependencies, SVGs or webfonts needed!
• 100% accessible, fast and easy-to-use
• Includes all 2078 icons
• Icons can be colored any color by setting color or background-color
• Icon size can be set with width and height (icons scale to fit with mask-size: contain)

By using CSS custom properties the icons can also be used as background-images instead of masks if needed.

Advantages of using CSS variables

• Theme-aware — Use a single stylesheet and change icon color via color or CSS variables; no need for separate icon assets per theme.
• One request — All icons live in one CSS file instead of hundreds of SVGs or a webfont, reducing HTTP requests.
• Override locally — Set --bi-* or background-color on any element (or a parent) to style icons without extra classes.
• Smaller payload — Icons are defined once as data URIs in variables; repeated use doesn’t duplicate the SVG data in the DOM.
• No JS — No runtime, no icon components, no tree-shaking step; works with plain HTML/CSS and any framework.
• Cascade-friendly — Icons inherit currentColor and variables from the cascade, so they fit naturally into your design system.

Usage

Include the stylesheet:

<link rel="stylesheet" href="bootstrap-icons.min.css" />

Each icon is exposed as a CSS variable --bi-<name> whose value is a url("data:image/svg+xml;utf8,...") data URI.

CSS classes (webfont-style)

Use the same class names as Bootstrap Icons: add the base class bi plus the icon class bi-<name>.

<i class="bi bi-0-circle"></i>
<i class="bi bi-heart"></i>
<i class="bi bi-star-fill" style="color: #ffd700"></i>
<i class="bi bi-cpu" style="height: 2rem; width: 2rem"></i>

Icons inherit color and default to 1rem. Resize with width and height.

As CSS variables (mask or background)

Use the variables anywhere—e.g. a repeating mask with custom color and size:

.my-banner {
  background-color: hotpink;
  display: inline-block;
  height: 3rem;
  mask-image: var(--bi-heart);
  mask-repeat: repeat;
  mask-size: 32px 32px;
  width: 640px;
}

Or as a background image with background-image: var(--bi-heart);, background-size: contain, etc.

Browser compatibility

mask-image is supported unprefixed in all modern browsers (Chrome 120, Safari 15.4, Firefox 53 — caniuse). To widen support (e.g. older Safari), use Autoprefixer to add -webkit-mask-image alongside mask-image. Because this uses CSS variables, the same variables are referenced from :root without increasing filesize. Neat!

File size

The stylesheet is approx 1.3 MB (~230 KB gzipped) and includes all 2078 icons. I recommend only including the CSS (or variables) for the icons you need to reduce file size and improve performance.

License

MIT