The following are key concepts for Hugo site customization with themes. Hugo permits you to supplement *or* override any theme template or static file with files in your working directory.
{{% note %}}
When you use a theme cloned from its git repository, do not edit the theme's files directly. Instead, theme customization in Hugo is a matter of *overriding* the templates made available to you in a theme. This provides the added flexibility of tweaking a theme to meet your needs while staying current with a theme's upstream.
{{% /note %}}
## Override Static Files
There are times where you want to include static assets that differ from versions of the same asset that ships with a theme.
For example, a theme may use jQuery 1.8 in the following location:
```
/themes/<THEME>/static/js/jquery.min.js
```
You want to replace the version of jQuery that ships with the theme with the newer `jquery-3.1.1.js`. The easiest way to do this is to replace the file *with a file of the same name* in the same relative path in your project's root. Therefore, change `jquery-3.1.1.js` to `jquery.min.js` so that it is *identical* to the theme's version and place the file here:
```
/static/js/jquery.min.js
```
## Override Template Files
Anytime Hugo looks for a matching template, it will first check the working directory before looking in the theme directory. If you would like to modify a template, simply create that template in your local `layouts` directory.
The [template lookup order][lookup] explains the rules Hugo uses to determine which template to use for a given piece of content. Read and understand these rules carefully.
This is especially helpful when the theme creator used [partial templates][partials]. These partial templates are perfect for easy injection into the theme with minimal maintenance to ensure future compatibility.
For example:
```
/themes/<THEME>/layouts/_default/single.html
```
Would be overwritten by
```
/layouts/_default/single.html
```
{{% warning %}}
This only works for templates that Hugo "knows about" (i.e., that follow its convention for folder structure and naming). If a theme imports template files in a creatively named directory, Hugo won’t know to look for the local `/layouts` first.
{{% /warning %}}
## Override Archetypes
If the archetype that ships with the theme for a given content type (or all content types) doesn’t fit with how you are using the theme, feel free to copy it to your `/archetypes` directory and make modifications as you see fit.
{{% warning "Beware of `layouts/_default`" %}}
The `_default` directory is a very powerful force in Hugo, especially as it pertains to overwriting theme files. If a default file is located in the local [archetypes](/content-management/archetypes/) or layout directory (i.e., `archetypes/default.md` or `/layouts/_default/*.html`, respectively), it will override the file of the same name in the corresponding theme directory (i.e., `themes/<THEME>/archetypes/default.md` or `themes/<THEME>/layout/_defaults/*.html`, respectively).
It is usually better to override specific files; i.e. rather than using `layouts/_default/*.html` in your working directory.
