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CSS variables

Use Boosted’s CSS custom properties for fast and forward-looking design and development.

Boosted includes many CSS custom properties (variables) in its compiled CSS for real-time customization without the need to recompile Sass. These provide easy access to commonly used values like our theme colors, breakpoints, and primary font stacks when working in your browser’s inspector, a code sandbox, or general prototyping.

All our custom properties are prefixed with bs- to avoid conflicts with third party CSS.

Root variables

Here are the variables we include (note that the :root is required) that can be accessed anywhere Boosted’s CSS is loaded. They’re located in our _root.scss file and included in our compiled dist files.

:root {
  --bs-blue: #527edb;
  --bs-indigo: #a885d8;
  --bs-purple: #a885d8;
  --bs-pink: #ffb4e6;
  --bs-red: #cd3c14;
  --bs-orange: #ff7900;
  --bs-yellow: #fc0;
  --bs-green: #32c832;
  --bs-teal: #50be87;
  --bs-cyan: #4bb4e6;
  --bs-white: #fff;
  --bs-gray: #999;
  --bs-gray-dark: #595959;
  --bs-gray-100: #fafafa;
  --bs-gray-200: #f6f6f6;
  --bs-gray-300: #eee;
  --bs-gray-400: #ddd;
  --bs-gray-500: #ccc;
  --bs-gray-600: #999;
  --bs-gray-700: #666;
  --bs-gray-800: #595959;
  --bs-gray-900: #333;
  --bs-primary: #ff7900;
  --bs-secondary: #000;
  --bs-success: #32c832;
  --bs-info: #527edb;
  --bs-warning: #fc0;
  --bs-danger: #cd3c14;
  --bs-light: #ccc;
  --bs-dark: #000;
  --bs-primary-rgb: 255, 121, 0;
  --bs-secondary-rgb: 0, 0, 0;
  --bs-success-rgb: 50, 200, 50;
  --bs-info-rgb: 82, 126, 219;
  --bs-warning-rgb: 255, 204, 0;
  --bs-danger-rgb: 205, 60, 20;
  --bs-light-rgb: 204, 204, 204;
  --bs-dark-rgb: 0, 0, 0;
  --bs-white-rgb: 255, 255, 255;
  --bs-black-rgb: 0, 0, 0;
  --bs-body-color-rgb: 0, 0, 0;
  --bs-body-bg-rgb: 255, 255, 255;
  --o-chevron-icon: url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 9 14'%3e%3cpath d='M9 2L7 0 0 7l7 7 2-2-5-5 5-5z'/%3e%3c/svg%3e");
  --o-close-icon: url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 30 30' fill='%23000'%3e%3cpath stroke='%23000' stroke-width='5' stroke-linecap='round' d='M15 17.121l-8.132 8.132-2.121-2.12L12.879 15 4.747 6.868l2.12-2.121L15 12.879l8.132-8.132 2.12 2.121L17.122 15l8.132 8.132-2.121 2.12L15 17.123z'/%3e%3c/svg%3e");
  --o-check-icon: url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 15 12'%3e%3cpath fill='%23000' d='M13 0L5 8 2 5 0 7l5 5L15 2z'/%3e%3c/svg%3e");
  --o-success-icon: url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 125 125'%3e%3cpath fill='%2332c832' d='M62.5 0a62.5 62.5 0 100 125 62.5 62.5 0 000-125zm28 29.4c3.3 0 6 2.6 6 5.9a5.9 5.9 0 01-1.3 3.7L57.7 86a5.8 5.8 0 01-9.1 0L29.8 62.5c-.8-1-1.2-2.3-1.2-3.7a5.9 5.9 0 011.7-4.1l2.3-2.4a5.8 5.8 0 014.2-1.7 5.8 5.8 0 013.8 1.4L52 64.7 86.6 31a5.8 5.8 0 014-1.6z'/%3e%3c/svg%3e");
  --o-error-icon: url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 140 125'%3e%3cpath fill='%23cd3c14' d='M70.3 0c-5.8 0-10.8 3.1-13.5 7.8L2.3 101.3l-.2.2A15.6 15.6 0 0015.6 125H125a15.6 15.6 0 0013.5-23.5L83.8 7.8A15.6 15.6 0 0070.3 0zm19.2 50a6.4 6.4 0 014.4 1.9 6.4 6.4 0 010 9L79.4 75.6l15 15a6.4 6.4 0 010 9.2 6.4 6.4 0 01-4.5 1.9 6.4 6.4 0 01-4.6-2l-15-15-15 15a6.4 6.4 0 01-4.6 2 6.4 6.4 0 01-4.6-2 6.4 6.4 0 010-9l15-15L46.8 61a6.4 6.4 0 119-9.1l14.6 14.5L84.8 52a6.4 6.4 0 014.7-1.9z'/%3e%3c/svg%3e");
  --bs-font-sans-serif: HelvNeueOrange/*rtl:insert:Arabic*/, Helvetica Neue, Helvetica, Arial, Liberation Sans, sans-serif, Apple Color Emoji, Segoe UI Emoji, Segoe UI Symbol, Noto Color Emoji;
  --bs-font-monospace: SFMono-Regular, Menlo, Monaco, Consolas, Liberation Mono, Courier New, monospace;
  --bs-gradient: linear-gradient(180deg, rgba(255, 255, 255, 0.15), rgba(255, 255, 255, 0));
  --bs-body-font-family: var(--bs-font-sans-serif);
  --bs-body-font-size: 1rem;
  --bs-body-font-weight: 400;
  --bs-body-line-height: calc(18 / 16);
  --bs-body-color: #000;
  --bs-body-bg: #fff;
}

Component variables

We’re also beginning to make use of custom properties as local variables for various components. This way we can reduce our compiled CSS, ensure styles aren’t inherited in places like nested tables, and allow some basic restyling and extending of Boosted components after Sass compilation.

Have a look at our table documentation for some insight into how we’re using CSS variables.

We’re also using CSS variables across our grids—primarily for gutters—with more component usage coming in the future.

Deduping embedded SVGs

Boosted uses embedded SVGs as data URIs in the wild, which means extremely long strings in CSS. When one of them is used several times in the stylesheet, CSS custom properties allows to factorize its string— thus to decrease output filesize.

:root {
  --o-chevron-icon: url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 9 14'%3e%3cpath d='M9 2L7 0 0 7l7 7 2-2-5-5 5-5z'/%3e%3c/svg%3e");
}

.back-to-top-link::after {
  background-image: var(--o-chevron-icon);
}

.pagination-item:first-child .page-link::before {
  background-image: var(--o-chevron-icon);
}

Examples

CSS variables offer similar flexibility to Sass’s variables, but without the need for compilation before being served to the browser. For example, here we’re resetting our page’s font and link styles with CSS variables.

body {
  font: 1rem/1.5 var(--bs-font-sans-serif);
}
a {
  color: var(--bs-blue);
}

Grid breakpoints

While we include our grid breakpoints as CSS variables (except for xs), be aware that CSS variables do not work in media queries. This is by design in the CSS spec for variables, but may change in coming years with support for env() variables. Check out this Stack Overflow answer for some helpful links. In the mean time, you can use these variables in other CSS situations, as well as in your JavaScript.