Create a Bootstrap Theme for WordPress

In this tutorial I will show you how to create a Bootstrap theme for WordPress. If you just want the finished product, feel free to download the theme from my repository.

It’s important to note that the theme has minimal styling, and serves as a blank slate for developers. The only assumption this theme makes is that you want to use Bootstrap. You can use as little or as much of the framework as you see fit. Below is the final result.

screenshot of Bootstrap theme for WordPressClick to expand

0. Install the WordPress Command Line

The WordPress Command Line is a Command line interface for WordPress. Simply put, this means that it can automate many tasks for us. One task is generating a starter theme. However, it can do much, much more.

1. Use the WordPress Command Line To Generate a New Starter Theme

Once you’ve installed the CLI, follow these steps to generate a base theme.

  1. In the root of your WordPress install, run wp scaffold _s slug_for_your_theme --activate. For the case of this tutorial, I will run wp scaffold _s wordpress-bootstrap-starter-theme --activate.
    • The wp scaffold _s function generates starter code for a theme based on _s (Underscores).
    • The Underscores Theme is created by Automatic, which is the same company that brings us WordPress. By default, it generates all files and directories needed for a valid WordPress theme.
    • Note that you can manually download the Underscores Theme, but using the CLI is much more effective.

If you navigate to the front end of your website, you should notice an underwhelming theme.

default underscores themeClick to expand

As underwhelming as it is, this starter theme meets all of WordPress’s theme development standards. In short, this means that all the necessary templates, functions and css are generated for you.

2. Install and Configure WPGulp

Now that we have a base theme configured, we’ll want it to be customized with Bootstrap’s CSS, JS and template files. Using a build tool like WPGulp helps speed up this process.

WPGulp is an advanced & extensively documented Gulp.js + WordPress workflow. It can help you kick-start a build-workflow for your WordPress plugins and themes with Gulp.js, save you a lot of grunt work time, follow the DRY (Don’t Repeat Yourself) principle, and #0CJS Zero-config JavaScript startup but still configurable via wpgulp.config.js file…

You can read about all of what WPGulp does, but some of my favorite features are…

  • Hot reloading
  • ES6 compiling
  • SASS compiling
  • Automatic image minification
  • Compiles all JS and CSS into one file each
  1. Follow the docs to install WPGulp.
    1. In my case I cd into my theme by running cd wp-content/themes/wordpress-bootstrap-starter-theme/.
    2. I then run npx wpgulp.
  2. Once installation is complete, you’ll want to edit the wpgulp.config.js file.
    1. Change the projectURL: 'wpgulp.local' variable to match your local development URL.
    2. If you plan on translating your site, make sure to update the translation options.

3. Update Your Theme’s File Structure To Work With WPGulp

Now that WPGulp is installed and configured, we’ll want to update our theme’s file structure to match the recommendations in the wpgulp.config.js. These updates are based on the styleSRC, jsVendorSRC, jsCustomSRC and imgSRC variables.

  1. Assuming you’re still in your theme’s directory, run the following commands.
    1. mkdir -p assets/css assets/js/vendor assets/js/custom assets/img/raw
  2. Now that the file structure matches the wpgulp.config.js configuration, we’ll want to move existing .css and .js files by running the following commands.
    1. mv style.css assets/css/style.scss
      • This moves the theme’s style.css file into the assets/css, and also changes it to a .scss file.
    2. mv js/customizer.js assets/js/custom/customizer.js
    3. mv js/skip-link-focus-fix.js assets/js/custom/skip-link-focus-fix.js
    4. rm -R js/
      • These commands simply move existing javascript files generated by the wp scaffold _s command into the new javascript directory.
      • Note that we did not keep js/navigation.js. This is an opinionated script to handle mobile navigation that ships with _s. This isn’t necessary since Bootstrap comes with it’s own navbar component.
    5. rm -R layouts/
      • This directory is generated by the wp scaffold _s command, and is not needed since Bootstrap ships with a layout system.

At this point your assets directory should look like this.

WPGulp assets directory structureClick to expand

4. Add Bootstrap

Now that we have a working a file structure, we can sprinkle in Bootstrap to our theme.

  1. Download the latest version of Bootstrap
    • At the time of this writing, the version is 4.3
    • Once unzipped, the folder should look something like this: Bootstrap file structureClick to expand
  2. Copy the scss directory and place it into assets/css/
  3. Rename the assets/css/scss directory to assets/css/bootstrap
  4. Copy dist/js/bootstrap.js and place it into assets/js/vendor
  5. Create a new directory called base in assets/css/
  6. Create the following files in assets/css/base
    1. _bootstrap_overrides.scss
    2. _forms.scss
    3. _wordpress.scss

At this point your assets directory should look like this.

WPGulp assets directory structure with BootstrapClick to expand

5. Update SCSS Partials and style.scss

Now that we’ve loaded Bootstrap into our theme, we need to update the partials in the base directory. We also need to update the style.scss file.

  1. Copy the css under # Forms in style.scss and paste into assets/css/base/_forms.scss

    /*--------------------------------------------------------------
# Forms
--------------------------------------------------------------*/
button,
input[type="button"],
input[type="reset"],
input[type="submit"] {
  border: 1px solid;
  border-color: #ccc #ccc #bbb;
  border-radius: 3px;
  background: #e6e6e6;
  color: rgba(0, 0, 0, 0.8);
  font-size: 12px;
  font-size: 0.75rem;
  line-height: 1;
  padding: 0.6em 1em 0.4em;
}

button:hover,
input[type="button"]:hover,
input[type="reset"]:hover,
input[type="submit"]:hover {
  border-color: #ccc #bbb #aaa;
}

button:active,
button:focus,
input[type="button"]:active,
input[type="button"]:focus,
input[type="reset"]:active,
input[type="reset"]:focus,
input[type="submit"]:active,
input[type="submit"]:focus {
  border-color: #aaa #bbb #bbb;
}

input[type="text"],
input[type="email"],
input[type="url"],
input[type="password"],
input[type="search"],
input[type="number"],
input[type="tel"],
input[type="range"],
input[type="date"],
input[type="month"],
input[type="week"],
input[type="time"],
input[type="datetime"],
input[type="datetime-local"],
input[type="color"],
textarea {
  color: #666;
  border: 1px solid #ccc;
  border-radius: 3px;
  padding: 3px;
}

input[type="text"]:focus,
input[type="email"]:focus,
input[type="url"]:focus,
input[type="password"]:focus,
input[type="search"]:focus,
input[type="number"]:focus,
input[type="tel"]:focus,
input[type="range"]:focus,
input[type="date"]:focus,
input[type="month"]:focus,
input[type="week"]:focus,
input[type="time"]:focus,
input[type="datetime"]:focus,
input[type="datetime-local"]:focus,
input[type="color"]:focus,
textarea:focus {
  color: #111;
}

select {
  border: 1px solid #ccc;
}

textarea {
  width: 100%;
}

  2. Update assets/css/base/_forms.scss with the following

    /*--------------------------------------------------------------
# Forms
--------------------------------------------------------------*/
button,
input[type="button"],
input[type="reset"],
input[type="submit"] {
  @extend .btn;
  @extend .btn-primary;
}

input[type="text"],
input[type="email"],
input[type="url"],
input[type="password"],
input[type="search"],
input[type="number"],
input[type="tel"],
input[type="range"],
input[type="date"],
input[type="month"],
input[type="week"],
input[type="time"],
input[type="datetime"],
input[type="datetime-local"],
input[type="color"],
textarea {
  @extend .form-control;
}

select {
  @extend .form-control;
}

textarea {
  @extend .form-control;
}

  3. Add the following css to assets/css/base/_wordpress.scss

    • These styles are taken from style.scss, which was originally style.css. This was generated by the wp scaffold _s command.
    • This file contains styles for WordPress Generated Classes.
    /*--------------------------------------------------------------
# Accessibility
--------------------------------------------------------------*/
/* Do not show the outline on the skip link target. */
#content[tabindex="-1"]:focus {
  outline: 0;
}

/*--------------------------------------------------------------
# Alignments
--------------------------------------------------------------*/
.alignleft {
  display: inline;
  float: left;
  margin-right: 1.5em;
}

.alignright {
  display: inline;
  float: right;
  margin-left: 1.5em;
}

.aligncenter {
  clear: both;
  display: block;
  margin-left: auto;
  margin-right: auto;
}

/*--------------------------------------------------------------
# Content
--------------------------------------------------------------*/
/*--------------------------------------------------------------
## Posts and pages
--------------------------------------------------------------*/
.sticky {
  display: block;
}

.post,
.page {
  margin: 0 0 1.5em;
}

.updated:not(.published) {
  display: none;
}

.page-content,
.entry-content,
.entry-summary {
  margin: 1.5em 0 0;
}

.page-links {
  clear: both;
  margin: 0 0 1.5em;
}

/*--------------------------------------------------------------
## Comments
--------------------------------------------------------------*/
.comment-content a {
  word-wrap: break-word;
}

.bypostauthor {
  display: block;
}

/*--------------------------------------------------------------
# Infinite scroll
--------------------------------------------------------------*/
/* Globally hidden elements when Infinite Scroll is supported and in use. */
.infinite-scroll .posts-navigation,
.infinite-scroll.neverending .site-footer {
  /* Theme Footer (when set to scrolling) */
  display: none;
}

/* When Infinite Scroll has reached its end we need to re-display elements that
were hidden (via .neverending) before. */
.infinity-end.neverending .site-footer {
  display: block;
}

/*--------------------------------------------------------------
# Media
--------------------------------------------------------------*/
.page-content .wp-smiley,
.entry-content .wp-smiley,
.comment-content .wp-smiley {
  border: none;
  margin-bottom: 0;
  margin-top: 0;
  padding: 0;
}

/* Make sure embeds and iframes fit their containers. */
embed,
iframe,
object {
  max-width: 100%;
}

/* Make sure logo link wraps around logo image. */
.custom-logo-link {
  display: inline-block;
}

/*--------------------------------------------------------------
## Captions
--------------------------------------------------------------*/
.wp-caption {
  margin-bottom: 1.5em;
  max-width: 100%;
}

.wp-caption img[class*="wp-image-"] {
  display: block;
  margin-left: auto;
  margin-right: auto;
}

.wp-caption .wp-caption-text {
  margin: 0.8075em 0;
}

.wp-caption-text {
  text-align: center;
}

/*--------------------------------------------------------------
## Galleries
--------------------------------------------------------------*/
.gallery {
  margin-bottom: 1.5em;
}

.gallery-item {
  display: inline-block;
  text-align: center;
  vertical-align: top;
  width: 100%;
}

.gallery-columns-2 .gallery-item {
  max-width: 50%;
}

.gallery-columns-3 .gallery-item {
  max-width: 33.33%;
}

.gallery-columns-4 .gallery-item {
  max-width: 25%;
}

.gallery-columns-5 .gallery-item {
  max-width: 20%;
}

.gallery-columns-6 .gallery-item {
  max-width: 16.66%;
}

.gallery-columns-7 .gallery-item {
  max-width: 14.28%;
}

.gallery-columns-8 .gallery-item {
  max-width: 12.5%;
}

.gallery-columns-9 .gallery-item {
  max-width: 11.11%;
}

.gallery-caption {
  display: block;
}

  4. Remove all css from style.scss, and replace with @import statements.

    /*
Theme Name: Wordpress-bootstrap-starter-theme
Theme URI: http://underscores.me/
Author: Me
Author URI: http://underscores.me/
Description: Custom theme: Wordpress-bootstrap-starter-theme, developed by Me
Version: 1.0.0
License: GNU General Public License v2 or later
License URI: LICENSE
Text Domain: wordpress-bootstrap-starter-theme
Tags: custom-background, custom-logo, custom-menu, featured-images,
threaded-comments, translation-ready
   
This theme, like WordPress, is licensed under the GPL.
Use it to make something cool, have fun, and share what you've learned with
others.
   
Wordpress-bootstrap-starter-theme is based on Underscores
https://underscores.me/, (C) 2012-2017 Automattic, Inc.
Underscores is distributed under the terms of the GNU GPL v2 or later.
   
Normalizing styles have been helped along thanks to the fine work of
Nicolas Gallagher and Jonathan Neal https://necolas.github.io/normalize.css/
*/

// Base Styles
@import "./base/bootstrap_overrides";
@import "./base/wordpress";
@import "./base/forms";

// Bootstrap Styles
@import "./bootstrap/bootstrap";

5. Update functions.php

Now that the assets directory is configured, we’ll need to update the theme’s functions.php file.

  1. Open up your theme’s functions.php file and scroll down to the Enqueue scripts and styles. section. It should look something like this.

    /**
 * Enqueue scripts and styles.
 */
function wordpress_bootstrap_starter_theme_scripts()
{
  wp_enqueue_style(
    "wordpress-bootstrap-starter-theme-style",
    get_stylesheet_uri()
  );

  wp_enqueue_script(
    "wordpress-bootstrap-starter-theme-navigation",
    get_template_directory_uri() . "/js/navigation.js",
    [],
    "20151215",
    true
  );

  wp_enqueue_script(
    "wordpress-bootstrap-starter-theme-skip-link-focus-fix",
    get_template_directory_uri() . "/js/skip-link-focus-fix.js",
    [],
    "20151215",
    true
  );

  if (is_singular() && comments_open() && get_option("thread_comments")) {
    wp_enqueue_script("comment-reply");
  }
}
add_action(
  "wp_enqueue_scripts",
  "wordpress_bootstrap_starter_theme_scripts"
);

    WPGulp will concatenate all javascript files in the assets/js/custom and assets/js/vendor directories into one file each. This means that we don’t need to individually load navigation.js and skip-link-focus-fix.js anymore. Note that these files were generated by the wp scaffold _s command, and aren’t required for every WordPress theme.

  2. Remove the existing wp_enqueue_script functions and replace with the following.

    • We load https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.7/umd/popper.min.js as this is a requirement for Bootstrap.
    • We added 'jquery' as an argument to the wp_enqueue_script function for the vendor-scripts. This is because Bootstrap requires jQuery.
    • We added 'customize-preview' as an argument to the wp_enqueue_script function for the custom-scripts. This is because the /assets/js/custom/customizer.js file generated by the wp scaffold _s is only loaded on the theme customizer page.
    • I chose to load the .min versions of each file, but you can load the unminified versions if you wish.
    • The vendor.min.js and custom.min.js files will be generated once we run WPGulp.
    /**
 * Enqueue scripts and styles.
 */
function wordpress_bootstrap_starter_theme_scripts()
{
  wp_enqueue_style(
    "wordpress-bootstrap-starter-theme-style",
    get_stylesheet_uri()
  );
  wp_enqueue_script(
    "wordpress-bootstrap-starter-theme-popper",
    "https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.7/umd/popper.min.js",
    ["jquery"],
    "20151215",
    true
  );

  wp_enqueue_script(
    "wordpress-bootstrap-starter-theme-vendor-scripts",
    get_template_directory_uri() . "/assets/js/vendor.min.js",
    ["jquery"],
    "20151215",
    true
  );
  wp_enqueue_script(
    "wordpress-bootstrap-starter-theme-custom-scripts",
    get_template_directory_uri() . "/assets/js/custom.min.js",
    ["customize-preview"],
    "20151215",
    true
  );
  if (is_singular() && comments_open() && get_option("thread_comments")) {
    wp_enqueue_script("comment-reply");
  }
}
add_action(
  "wp_enqueue_scripts",
  "wordpress_bootstrap_starter_theme_scripts"
);

  3. Run npm start to make sure everything is working. You should be able to open up http://localhost:3000/ and see your site. It should look similar to the following:

    Bootstrap Underscores ThemeClick to expand

  4. To ensure everything is hooked up correctly, let’s override the $primary Bootstrap variable.

  • Open assets/css/base/_bootstrap_overrides.scss and add $primary: green;

    'Testing Bootstrap Underscores Theme'Click to expand

5. Update Header Markup

At this point we have everything we need to start building a Bootstrap theme. However, there are two small edits we should make. The current header.php file should look like this.

<div id="page" class="site">
    <a class="skip-link screen-reader-text" href="#content"><?php esc_html_e(
      "Skip to content",
      "wordpress-bootstrap-starter-theme"
    ); ?></a>

    <header id="masthead" class="site-header">
        <div class="site-branding">
            <?php
            the_custom_logo();
            if (is_front_page() && is_home()): ?>
                <h1 class="site-title"><a href="<?php echo esc_url(
                  home_url("/")
                ); ?>" rel="home"><?php bloginfo("name"); ?></a></h1>
                <?php else: ?>
                <p class="site-title"><a href="<?php echo esc_url(
                  home_url("/")
                ); ?>" rel="home"><?php bloginfo("name"); ?></a></p>
                <?php endif;
            $wordpress_bootstrap_starter_theme_description = get_bloginfo(
              "description",
              "display"
            );
            if (
              $wordpress_bootstrap_starter_theme_description ||
              is_customize_preview()
            ): ?>
                <p class="site-description"><?php echo $wordpress_bootstrap_starter_theme_description;
              /* WPCS: xss ok. */
              ?></p>
            <?php endif;
            ?>
        </div><!-- .site-branding -->

        <nav id="site-navigation" class="main-navigation">
            <button class="menu-toggle" aria-controls="primary-menu"
aria-expanded="false"><?php esc_html_e(
  "Primary Menu",
  "wordpress-bootstrap-starter-theme"
); ?></button>
            <?php wp_nav_menu([
              "theme_location" => "menu-1",
              "menu_id" => "primary-menu",
            ]); ?>
        </nav><!-- #site-navigation -->
    </header><!-- #masthead -->

    <div id="content" class="site-content">
  1. Update the skip link class to use Bootstrap’s screen reader, and remove the button.menu-toggle button, since that was specific to the _s theme.
<div id="page" class="site">
    <a class="sr-only sr-only-focusable" href="#content"><?php esc_html_e(
      'Skip
to content',
      "wordpress-bootstrap-starter-theme"
    ); ?></a>

    <header id="masthead" class="site-header">
        <div class="site-branding">
            <?php
            the_custom_logo();
            if (is_front_page() && is_home()): ?>
                <h1 class="site-title"><a href="<?php echo esc_url(
                  home_url("/")
                ); ?>" rel="home"><?php bloginfo("name"); ?></a></h1>
                <?php else: ?>
                <p class="site-title"><a href="<?php echo esc_url(
                  home_url("/")
                ); ?>" rel="home"><?php bloginfo("name"); ?></a></p>
                <?php endif;
            $wordpress_bootstrap_starter_theme_description = get_bloginfo(
              "description",
              "display"
            );
            if (
              $wordpress_bootstrap_starter_theme_description ||
              is_customize_preview()
            ): ?>
                <p class="site-description"><?php echo $wordpress_bootstrap_starter_theme_description;
              /* WPCS: xss ok. */
              ?></p>
            <?php endif;
            ?>
        </div><!-- .site-branding -->
        <nav id="site-navigation" class="main-navigation">
            <?php wp_nav_menu([
              "theme_location" => "menu-1",
              "menu_id" => "primary-menu",
            ]); ?>
        </nav><!-- #site-navigation -->
    </header><!-- #masthead -->

    <div id="content" class="site-content">

screenshot of Bootstrap theme for WordPressClick to expand