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Customization and Styling

When using fsdocs, there are six levels of extra content development and styling.

  1. Don't do any styling or documentation customization and simply write content. This is by far the simplest option to maintain.

  2. Add content such as an docs/index.md to customize the front-page content for your generated docs. You can also add content such as docs/reference/fslib.md to give a bespoke landing page for one of your namespaces, e.g. here assumed to be namespace FsLib. This will override any generated content.

  3. Customize via Styling Parameters
  4. Customize via CSS
  5. Customize via a new template
  6. Customize by generating your own site using your own code

By default fsdocs does no styling customization and uses the following defaults. These are the settings used to build this site.

For your project, you don't need any of these files. However you can add them if you wish, though if you adjust them there is no guarantee that your template will continue to work with future versions of F# Formatting.

Customizing via Styling Parameters

The following content parameters are particularly related to visual styling:

Substitution name

Value (if not overriden by --parameters)












<FsDocsReleaseNotesLink> else <PackageProjectUrl>/blob/master/RELEASE_NOTES.md




<FsDocsTheme>, must currently be default

These basic entry-level styling parameters can be set in the project file or Directory.Build.props. For example:

    <!-- Example ultra-simple styling and generation settings for FsDocs default template-->

As an example, here is a page with alternative styling.

Customizing via CSS

You can start styling by creating a file docs/content/fsdocs-theme.css and adding entries to it.
It is loaded by the standard template.

CSS variables

The default template is heavily based on CSS variables. These can easily be override to customize the look and feel of the default theme.
A full list of the overrideable variables can be found here.

:root {
    --text-color: red;

[data-theme=dark] {
    --text-color: darkred;

Please be aware that the dark mode in the default theme is using the same variables. When you override a variable, it will also be used in dark mode unless redefined in a [data-theme=dark] CSS query.

CSS classes

The API documentation uses a set of fixed CSS classes:

CSS class

Corresponding Content


generated tooltips


generated xmldoc sections


generated member lists (tables)


usage in generated member lists


tooltips in generated member lists


documentation in generated member lists


generated entity lists


generated entity lists


documentation in generated entity lists


generated exception lists


the 'summary' section of an XML doc


the 'remarks' section of an XML doc


the 'parameters' section of an XML doc


a 'parameter' section of an XML doc


a 'parameter' name of an XML doc


the 'returns' section of an XML doc


the 'example' section of an XML doc


the 'notes' section of an XML doc


a paragraph of an XML doc

Some generated elements are given specific HTML ids:

HTML element selector



The navigation-bar


The main menu on the left side


The generated content


The sub menu on the right side


The search dialog

dialog input[type=search]

The search box


The logo

If you write a new theme by CSS styling please contribute it back to FSharp.Formatting.

Customizing via a new template

You can do advanced styling by creating a new template. Add a file docs/_template.html, likely starting with the existing default template.

NOTE: To enable hot reload during development with fsdocs watch in a custom _template.html file, make sure to add the single line {{fsdocs-watch-script}} to your <head> tag. NOTE: There is no guarantee that your template will continue to work with future versions of F# Formatting. If you do develop a good template please consider contributing it back to F# Formatting.

Customizing menu items by template

You can add advanced styling to the sidebar generated menu items by creating a new template for it. fsdoc will look for menu templates in the --input folder which defaults to the docs folder.

To customize the generated menu-item headers, use file _menu_template.html with starting template:

<li class="nav-header">

Similarly, to customize the individual menu item list, use file _menu-item_template.html with starting template:

<li class="nav-item"><a href="{{fsdocs-menu-item-link}}" class="nav-link">{{fsdocs-menu-item-content}}</a></li>

Do note that files need to be added prior running or won't be generated. In case you want to get a unique identifier for a header or menu item, you can use {{fsdocs-menu-header-id}} and {{fsdocs-menu-item-id}}, respectively.

Injecting additional html into the default template

Occasionally, you may find the need to make small customizations to the default template, such as adding a Google Analytics snippet or including additional style or script tags. To address this scenario, you can create two files: _head.html and/or _body.html.

The content within these files will serve as replacements for the {{fsdocs-head-extra}} and {{fsdocs-body-extra}} placeholders, which are utilized in the default template.

Customizing by generating your own site using your own code

The FSharp.Formatting.ApiDocs namespace includes a GenerateModel that captures the results of documentation preparation in ApiDocsModel and allows you to generate your own site using your own code.

NOTE: The ApiDocsModel API is undergoing change and improvement and there is no guarantee that your bespoke site generation will continue to work with future versions of F# Formatting. NOTE: The ApiDocsModel currently includes some generated HTML with some specific style tags. In the long term these may be removed from the design of that component.

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