This article explains how WordPress themes work and how to customise them safely without losing your changes.
What Are WordPress Themes
A WordPress theme controls how your website looks. It contains template files that tell WordPress how to display your content, including colours, fonts, layouts, and where elements appear on each page.
Themes are made up of PHP files, CSS stylesheets, and sometimes JavaScript. The main theme files include:
style.css- Controls colours, fonts, and layoutindex.php- The main template fileheader.phpandfooter.php- Header and footer sectionsfunctions.php- Adds features and functionality
Installing New Themes
To change your website's appearance, you can install new WordPress themes. Web60 includes access to thousands of free themes, plus you can upload premium themes you've purchased.
Go to your WordPress admin dashboard, click Appearance > Themes, then "Add New" to browse available options. Always preview a theme before activating it to see how it looks with your content.
Understanding Child Themes
If you want to customise a theme's code, you must use a child theme. A child theme inherits all the functionality of its parent theme but keeps your customisations separate.
Without a child theme, any code changes you make will disappear when the theme updates. This is why understanding WordPress child themes is essential before making modifications.
Child themes contain:
- Their own
style.cssfile for custom CSS - A
functions.phpfile for custom code - Any template files you want to modify
Basic Theme Customisation
Most theme changes can be made through WordPress's built-in Customizer (Appearance > Customize). This lets you:
- Change colours and fonts
- Upload logos and images
- Modify layouts
- Add custom CSS
For more advanced styling, you can add custom CSS styling through the Customizer's Additional CSS section. This method is safe and won't be lost during theme updates.
When to Modify Theme Files
Only edit theme files directly if you need functionality that can't be achieved through the Customizer or plugins. Always:
- Create a child theme first
- Back up your website
- Test changes on a staging site if possible
- Keep a record of what you've modified
Common file modifications include customising the header layout, changing how posts are displayed, or adding new template sections.
Theme Development Best Practices
If you're creating custom templates:
- Follow WordPress coding standards
- Make themes responsive for mobile devices
- Test with different content types and lengths
- Ensure accessibility for users with disabilities
- Keep code organised and well-commented
Remember that themes should handle presentation, while functionality belongs in plugins. This keeps your site flexible if you change themes later.
If you're still stuck with theme customisation, contact Web60 support for guidance on the best approach for your specific needs.
FAQ
Q: Will I lose my customisations if I update my theme?
A: Yes, if you've modified the theme files directly. This is why you should always use a child theme for customisations, as it protects your changes from theme updates.
Q: Can I edit my theme's PHP files through WordPress?
A: Yes, go to Appearance > Theme Editor, but this is risky. One mistake can break your website. Always create a backup first and use a child theme.
Q: How do I know if my theme is mobile-friendly?
A: Check your website on different devices or use Google's Mobile-Friendly Test tool. Most modern themes are responsive, but older themes may need updates.
Q: What's the difference between a theme and a template?
A: A theme is the complete design package for your website. Templates are individual files within the theme that control specific page types like the homepage or blog posts.
Q: Can I use multiple themes on one WordPress site?
A: No, only one theme can be active at a time. However, you can install multiple themes and switch between them as needed.
Q: Why does my website look different after changing themes?
A: Each theme has its own design and layout structure. Your content remains the same, but how it's displayed changes. Some themes may not support features your previous theme had.
Q: How do I find theme files on my server?
A: Themes are stored in the /wp-content/themes/ folder. Each theme has its own subfolder containing all its files.
Last updated: 1 March 2026