# Style Customization

All the Widgets in this catalog are based on a simple design, based on Bootstrap, waiting to be modified to suit the client's designs and guidelines. Remember that these Widgets are intended to be used as a base for the final product and not as a product by itself.

For both the style base, as well as the grid used in the Widgets, Bootstrap (opens new window) is used in its 4.5.x version, using the helpers and classes it includes as much as possible. This way the number of custom styles in our Widgets is very low, which makes modifying them simple and easy.


To take full advantage of Bootstrap's potential, we use SCSS as a pre-processor for css, which allows us to modify the default values of the variables used in the Bootstrap build.


<div class="bg-white px-3 pt-3 pb-2 rounded mt-3">
  <div class="d-flex justify-content-between mb-2">
    <!-- content -->

# File structure and style loading

In the “src” folder of the project we will find a folder called “scss” that has the following structure:


├── src/
│   ├── ...
│   ├── scss/
│   │   ├── _theme.scss
│   │   ├── _variables.scss
│   │   └── custom.scss
│   ├── ...

# Topic

The _theme.scss file is used for:

  • Global Widget Styles
  • Extend bootstrap using your mixins




//Example: we use the bg-variant mixin to create more background colors
@include bg-variant (“.bg-tertiary”, $tertiary, true);
@include bg-variant (“.bg-tertiary-10", $tertiary-10, true);

//In the following examples we use the button-variant mixin that allows us to create new buttons with all their states
.btn-tertiary {
 @include button-variant ($tertiary, $tertiary);
.btn-outline-tertiary {
 @include button-outline-variant ($tertiary, $white, $primary-80, $primary-80);
 color: $secondary-100;


You can find a list of available mixins here (opens new window) and a detailed explanation here (opens new window)

# Variables

The _variables.scss file contains all the Bootstrap default variables (colors, sizes, buttons, etc). Here you can change the values we need to fit the Bootstrap base styles to our design, thus avoiding having to overwrite or add more classes to the project (you can read more about how to modify Bootstrap here (opens new window)).

# Example


// ...
$light: $secondary-10;
// ...
$border-width: 1px;
$border-color: $primary-10;
$border-radius: 0.35rem;
Image with the CSS before the edits




// ...
$light: lightblue;
// ...
$border-width: 2px;
$border-color: $secondary;
$border-radius: 1.35rem;
Image with the CSS after the edits

# Custom SCSS

In the custom.scss file import and sort all the other stylesheets you have in the scss folder along with the Bootstrap base:


@import "./variables"; // always before Bootstrap
@import "~bootstrap";
@import "./theme.scss";


The order is important, variables always go before you import Bootstrap.

The custom.scss file is imported into the project's main.js.


import Vue from "vue";
import "bootstrap"; // only imports javascript, not the styles
import "./scss/custom.scss";
new Vue({
  render: (h) => h(App),


The @import 'bootstrap' of this file only imports bootstrap.js and not the styles!

# Component styles

Some of the Widgets components have their own styles, and these are written in the same component (.vue). This way we can define the scope of these styles at the component level without affecting other parts of the Widget using the scoped attribute.




<style lang="scss" scoped>
  .consumer-loan-months-selector {
    .card {
      border: 1px solid $primary-10;
    .card-header {
      padding: 0.75rem 1.25rem;

# PurgeCSS

When you're building a Widget with Bootstrap (or another styling framework) you'll only use a small set of it, and many unused CSS styles will be included. This is where PurgeCSS comes into play. PurgeCSS analyzes your content and CSS files. It then matches the selectors used in your files with those in your content files and removes unused selectors from your CSS, resulting in smaller CSS files.

Widgets use PurgeCSS (opens new window) in conjunction with PostCSS (opens new window) as part of the development flow. This way we managed to optimize the size of our Widgets.

# PostCSS

What about styles NOT declared in the content, but that ARE used in the Widget? Sometimes styling problems occur, for example when the Bootstrap modal component is used and the modal-backdrop style does not load because this element is created dynamically when we open the modal; or when we use external component libraries in our Widgets where the styles of that component have not been loaded and they're not loaded on the site. This happens because PurgeCSS does not know where to read the contents of the external component.

To include the styles that PurgeCSS has removed but that we need on the site we need to declare them in a PostCSS config file. This file is located at the root of the Widget and is called postcss.config.js

const PURGE_CSS = require("@fullhuman/postcss-purgecss");

const IN_PRODUCTION = process.env.NODE_ENV === "production";
const plugins = {};

  plugins.purgecss = PURGE_CSS({
    content: ["./public/**/*.html", "./src/**/*.vue"],
    defaultExtractor(content) {
      const contentWithoutStyleBlocks = content.replace(
      return (
        contentWithoutStyleBlocks.match(/[A-Za-z0-9-_/:]*[A-Za-z0-9-_/]+/g) ||
    whitelist: [],
    whitelistPatterns: [
// ...

In this file you can force PurgeCSS to include styles in 3 different ways:

  1. Add the content file to the content property, so PurgeCSS is able to read the content and determine what styles it should include.


// ...
plugins.purgecss = PURGE_CSS({
  content: [
  defaultExtractor(content) { // block code }
// ...
  1. Add keywords to the whitelist property


  defaultExtractor(content) { // block code }
  whitelist: ['modal-backdrop', 'fade', 'show'],
  1. Add regex patterns to whitelistPatterns


// ...
  defaultExtractor(content) { // block code }
  whitelist: ['fade', 'show'],
  whitelistPatterns: [
  // ...
// ...
Last Updated: 10/11/2022,