Master Your Site: Customizing WordPress Themes

Just as a house is more than bricks and mortar, a WordPress site is much more than simple code. It’s a cohesive structure built with various layers such as PHP, HTML, CSS, and other key elements. Customizing WordPress themes involves gaining an in-depth understanding of this structure, learning to inspect and adjust design elements with HTML and CSS, modifying functions, and mastering the use of plugins & Page Builders. This journey allows for optimal customization, transforming a default theme into a truly personalized and functionally rich digital landscape.

Understanding WordPress Structure

Understanding PHP and Template Hierarchy in WordPress

In a WordPress theme, PHP and template hierarchy are integral components. PHP is the coding language largely used in WordPress. It’s the backbone that determines the functionality of your website. By understanding and altering PHP files, you can change how certain features on your site behave.

WordPress template hierarchy, on the other hand, is the system WordPress uses to understand which template file will be used to generate a specific page on your website. The template hierarchy consists of various PHP files that are used depending on the content being requested. For example, the index.php file serves as the default template.

Significance of HTML and CSS

HTML and CSS are critical for adjusting your website’s design in WordPress themes. HTML (HyperText Markup Language) forms the structure of your web pages and is responsible for displaying your website content in the web browser.

CSS, or Cascading Style Sheets, is used to style the HTML elements. This includes things like colors, fonts, layout, and other aspects of the design. By understanding how HTML and CSS work, you can make detailed adjustments to the overall appearance and layout of your WordPress site.

The Importance of Child Themes

When customizing a WordPress theme, using a child theme is paramount. A child theme is a subordinate theme that inherits all the features and appearance of its parent theme. It allows you to make changes and customize your site without affecting the original parent theme files.

The importance of a child theme lies in the way it preserves your customizations. Whenever the parent theme is updated, changes made directly within the theme files can be lost. However, by using a child theme, your modifications will remain intact even after updating the parent theme.

To create a child theme, you’ll need to make a new directory in your themes directory. This will hold the child theme’s PHP and CSS files. From there, you can enqueue the parent and child theme stylesheets, copy any necessary files from the parent theme, and begin customizing.

Remember, learning and experimenting with WordPress structure and its components will essentially help you customize your themes efficiently. It’s also recommended to take backups of your site before making any major changes to avoid any unwanted results.

Image depicting the structure of a WordPress theme and its components

Customizing HTML and CSS

Understanding HTML and CSS in WordPress

HTML (Hypertext Markup Language) is the standard language for creating websites. CSS (Cascading Style Sheets) allows you to apply styles (like colors, fonts, and layouts) to web pages and influences how HTML elements are displayed. WordPress themes are written in HTML and CSS.

Using Browser Tools to Inspect Elements

Most browsers have inspection tools for developers, which will be useful in understanding how the theme is structured. Right-click on an element you want to inspect and select ‘Inspect Element’ or ‘Inspect’ depending on your browser. This brings up the inspection pane that shows the HTML elements and CSS rules applied.

Modifying CSS in the WordPress Customizer

The WordPress Customizer allows for live previews of any changes made to your site. In your WordPress dashboard, navigate to ‘Appearance’ > ‘Customize’ > ‘Additional CSS’. Here, you can add your custom CSS rules. As you add or modify CSS rules, the changes will appear in real-time in the preview window. Remember to click ‘Publish’ or ‘Save Draft’ when you’re done, to implement the changes.

Adding Custom CSS Classes into HTML

Sometimes, you may need to apply styles to specific HTML elements only. In these cases, you can add custom CSS classes directly into the HTML. For example, if you wish to style all paragraphs with the class ‘special-text’, in your HTML you would write <p class=”special-text”> and in your CSS, you would write .special-text { your styles here }.

Responsive Design Fundamentals

Responsive design ensures your website looks good on all devices, regardless of screen size. The use of media queries in your CSS allows you to apply different styles depending on the size of the viewer’s screen. For example, you could have a CSS rule like @media screen and (max-width: 700px) { body { font-size: 16px; } }, which would decrease the body font size when viewed on screens smaller than 700 pixels wide.

Final Note

Always make sure to test your changes on various devices and browsers to ensure your design is responsive and accessible. And remember, it’s crucial to backup your website before making any major changes, just in case something goes wrong.

Illustration of a person writing code on a computer screen

Working with WordPress Functions

Understanding the functions.php File in a Child Theme

The functions.php file is like a plugin for your WordPress child theme, acting as an essential component to extend the functionality of the parent theme. Located in your child theme’s directory, this file allows you to add features or modify the behaviors of your site without touching the original code of the parent theme.

How to Create a Child Theme’s functions.php File

Initially, your child theme might not contain a functions.php file. To create one, you must manually add it using an FTP client or the file manager of your hosting control panel.

  1. Navigate to the directory of your child theme.
  2. Create a new file and name it “functions.php”.
  3. Open the file in a text editor.
  4. Add an opening PHP tag at the top of the file (<?php).

Now you have a blank functions.php file ready to be utilized.

Adding Actions in functions.php

Actions are triggered by specific events that occur in WordPress. You can add actions using the add_action() function. This function needs two parameters, the name of the action hook and the name of the function to be executed.

For example, you could add a piece of code that is executed after the setup of the WordPress theme:

        // sample code
add_action( 'after_setup_theme', 'your_function' );

function your_function() {
    // Your code here.

Modifying and Removing Actions

To modify actions, you need to first remove the action and then add it back with your modifications.

Example of how to remove an action:

        // sample code
remove_action( 'action_hook', 'function_to_remove', $priority);


You can then add your customized action back using the add_action() function as shown above.

Using Filters in functions.php

Filters allow you to modify certain functions. They are added using the add_filter() function, which requires the same parameters as add_action().

Example of adding a filter:

        // sample code
add_filter('login_errors', 'override_login_errors');

function override_login_errors(){
   return 'Invalid login details.';

In this example, the ‘login_errors’ filter is being modified to return a custom error message when invalid login details are entered.

Understanding Shortcodes in functions.php

Shortcodes in WordPress allow you to create special content (forms, buttons, etc.) that can be reused across various posts or pages.

To create a shortcode, you use the add_shortcode() function:

        // sample code
add_shortcode('your_shortcode', 'your_shortcode_function');

function your_shortcode_function(){
    // Your code here.

The first parameter is the text used to call the shortcode and the second parameter is the function that runs when the shortcode is called.

Registering Widgets in functions.php

A widget often adds a specific feature or function to your WordPress site that’s accessible from the WordPress widgets screen.

To register a sidebar or a widget area, use the register_sidebar() function with parameters that define the ID, name, and description.

        // sample code
function your_widgets_init() {
            'name' => __( 'Your Sidebar', 'your_theme' ),
            'id' => 'your_sidebar',
            'description' => __( 'Widgets in this area will be shown on all posts and pages.', 'your_theme' ),
add_action( 'widgets_init', 'your_widgets_init' );

In this example, a new sidebar is being registered called “Your Sidebar”. Now you will be able to see this sidebar from the Widgets Screen.

Remember to Backup

Before you make any changes to your functions.php file, it’s always a good idea to backup your WordPress site. This prevents any unfortunate loss of data if something goes wrong.

Illustration of a child theme's functions.php file with code and WordPress logo

Plugins & Page Builders

Understanding WordPress Plugins and Page Builders

WordPress plugins and Page Builders like Elementor and Beaver Builder are powerful tools that can greatly enhance the functionality and aesthetics of your website. They simplify the process of customizing your theme by providing pre-built elements and layouts that can be adjusted and arranged to your liking. These tools offer drag-and-drop functionality and real-time preview modes, allowing you to design your site without needing to write any code.

How to Customize WordPress Themes with Plugins

Firstly, you need to install your desired plugin from the WordPress marketplace. Navigate to the Plugins menu in your WordPress dashboard, search for the plugin you want, install and then activate it. Once activated, the plugin will add its own set of options to your WordPress interface. You can use these options to customize various aspects of your website.

For instance, you might install a social sharing plugin that lets you add social share buttons to your posts and pages. After installing the plugin, you navigate to its settings and choose what types of social buttons you want to display, where you want them to appear, etc. You apply these changes and your website will now show the selected social buttons in the chosen areas.

Customizing with Page Builders

When it comes to page builders like Elementor or Beaver Builder, they give more fine-grained control over the details of your page layout. You can drag and drop various elements (like headers, images, text blocks, etc.) onto your page, and then move and resize those elements as desired.

To use one of these page builders, you need to install and activate it just like a plugin. Once activated, you create a new page or edit an existing one, and then choose to edit it with the page builder. You’re presented with a blank canvas (for a new page) or the current layout (for an existing page). On the side, you’ll find a panel with all the elements you can add to your page. Drag an element into the page, and then adjust its properties in the panel.

Going Beyond Plugins and Builders with Custom Coding

While WordPress plugins and Page Builders are remarkably powerful and user-friendly, they do have their limitations. When you desire a feature or style that’s beyond what these tools can offer, you may need to resort to custom coding.

For example, you might want to add a custom post type to your website. While there are plugins that can do this, you have more control when doing it through code. You can add the necessary PHP code to your theme’s functions.php file, ensuring it meets WordPress coding standards.

Additionally, CSS can be used to customize the appearance of your theme beyond what a Page Builder allows. You can access your site’s CSS file through the WordPress Theme Editor or by using a child theme. By learning the basics of CSS, you can alter the display of elements like headers, footers, and sidebars, enabling you to fully tweak your WordPress theme to match your vision.

In conclusion, while relying solely on WordPress plugins and Page Builders can limit customization to a certain extent, a basic understanding of PHP and CSS coding can provide you with unlimited customization opportunities for your WordPress theme.

An image of a person using a computer and designing a website with WordPress plugins and page builders

Photo by markadriane on Unsplash

It’s an exciting journey, learning how to customize WordPress themes. The secrets of the architecture lie in appreciating the underlying structure and learning how to modify it with HTML, CSS and PHP. Introducing plugins and Page Builders accelerates your design process and complements your burgeoning coding skills, giving you the best of both worlds. As you grow in your understanding and ability, your WordPress site evolves with you, moving from a generic platform to reflect your unique vision and purpose.

Toby Cryns

Toby Cryns is a freelance CTO and WordPress Guru. He also writes for