CMS websites
WordPress theme customization
Some WordPress sites start from a theme that nearly fits: the layout is close, but the colours, fonts, header, page templates or a few features need to change. Customising a theme can be the quickest route to a site that looks like your brand, provided the changes are made in a way that survives theme updates, stays within what the theme was designed to do, and leaves the site maintainable. Pushed too far, customisation can cost more than building templates designed for the site.
This page covers what is usually customised, how to keep changes safe through updates, the difference between working in settings and in code, the limits of customising and how to decide when to stop. LetGetGrow builds, redesigns and maintains WordPress and Webflow websites, with the scope, cost and timeline of each project set out in a custom quotation.
Illustrative diagram
Theme customisation
- Settings
- Colours
- Fonts
- Logo
- Styles
- Global styles
- Patterns
- CSS
- Code
- Child theme
- Templates
- Functions
Levels of customisation
| Level | Examples | Risk on update |
|---|---|---|
| Theme settings | Colours, fonts, logo, layout options | Low |
| Editor styles and patterns | Saved block layouts, global styles | Low to moderate |
| Custom CSS | Spacing, small visual changes | Moderate if selectors change |
| Template and code changes | New templates, changed markup, functions | Higher unless kept separate |
Settings before code
Start with what the theme offers through its settings and the WordPress editor. Changes made there are designed to survive updates and are easy for the next person to find. Move to custom CSS or code only for what settings cannot do, and keep a record of every change and why it was made.
Keeping changes through updates
Editing a theme's own files directly is risky: the next update can overwrite those edits. For classic themes, a common approach is a child theme, a small separate theme that holds your changes and inherits everything else. Block themes keep many style choices in the editor's global styles and templates. Whichever applies, keep customisations separate from the original theme so it can still be updated safely.
Block themes and classic themes
Newer block themes let you edit headers, footers and templates in the site editor, which puts more control in editors' hands. Classic themes rely more on theme options and code. Find out which kind your theme is before planning changes, since the approach and the effort differ.
A safe customisation process
Review the theme
Maintained? Block or classic? Options available?
Output: Theme notes
List changes
Each change and its purpose.
Output: Change list
Work on staging
Settings first, then separate code.
Output: Customised staging site
Test an update
Apply a theme update on staging.
Output: Changes confirmed safe
Document
Record every change.
Output: Customisation log
Example: adapting a theme for a café group
Illustrative example — not a client case study
Situation: A small café group uses a popular theme but wants its own fonts, a simpler header and a menu page layout.
- Fonts and colours are set through the theme's global styles.
- The header is simplified in the site editor, and a menu page pattern is saved for reuse.
- One remaining spacing issue is fixed in a small, documented CSS addition.
What this shows: The site matched the brand and still updated cleanly. This example is illustrative.
Theme customisation checks
Safety
- Original theme files untouched
- Update tested on staging
Record
- Customisation log kept
- Reason for each code change
Fit
- Editors can still update pages
- Mobile layouts checked
Knowing the limits
Every theme has a structure. When the list of changes starts to rewrite its templates, override most of its styles or fight its layout system, customising may cost more than building templates designed for your site. A useful test: if more than a handful of templates need structural change, compare the cost of a custom build.
Is the theme maintained?
Before investing in customisation, check that the theme is still updated by its author and works with current WordPress versions. Customising an abandoned theme builds on ground that will not be repaired.
Speed and accessibility
Customisations can add weight: extra fonts, scripts and large images. Load only the fonts and features you use. Check that colour changes keep sufficient contrast and that custom elements work with a keyboard.
Handing over a customised theme
Whoever maintains the site next needs to know what was changed. A short customisation log, listing settings changed, CSS added and any child theme or template changes, saves them from rediscovering everything.
Questions about WordPress theme customization
What can be customised in a WordPress theme?
Colours, fonts, layouts, headers, templates and, with code, much more.
Will customisations survive theme updates?
Yes, if they are kept separate from the original theme files.
What is a child theme?
A separate theme that holds changes and inherits the rest from a classic parent theme.
Should we use settings or code?
Settings first; code only for what settings cannot do.
When should we stop customising?
When changes rewrite most templates; compare a custom build.
Do premium themes need licences?
Often, to receive updates; keep them in the business's name.
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