site/themes/hugo-theme-gruvbox/README.md

# Gruvbox Hugo Theme

A retro-looking [Hugo](https://gohugo.io/) theme inspired by
[gruvbox](https://github.com/morhetz/gruvbox) to build secure, fast, and
SEO-ready websites.

This theme is easily customizable with features that any coder loves.

I took a lot of inspiration from the
[Hello Friend](https://github.com/panr/hugo-theme-hello-friend) and
[Doks](https://github.com/h-enk/doks) Hugo themes.

## DEMO [https://hugo-theme-gruvbox.schnerring.net/](https://hugo-theme-gruvbox.schnerring.net/)

![Screenshot of the theme in dark and light colors](https://raw.githubusercontent.com/schnerring/hugo-theme-gruvbox/main/images/tn.png)

## DISCLAIMER: Project Status

This theme is still in early development.
[Check out the issues](https://github.com/schnerring/hugo-theme-gruvbox/issues)
to see what's still missing.

## Highlights

- [Code highlighting with Prism](#prism)
- Full-text search with [Flex Search](https://github.com/nextapps-de/flexsearch)
- Display your CV using structured [JSON Resume](https://jsonresume.org/) data
- [Integrated image optimization with next-gen image formats and lazy loading](#image-optimization)
- Dark mode that also changes Prism themes
- [Dynamic color choices from the Gruvbox color palette](#colors)
- [Extensible to make it suit your needs](#extensibility)
- Responsive, mobile-first design
- Beautiful SVG icons with [Tabler Icons](https://tabler-icons.io/)

A big thank you to the authors of the software that make this theme possible! ❤️

## Quickstart

The theme requires _extended_ Hugo because it uses Sass/SCSS. You'll also have
to install Go because the theme uses Go modules.

1. `git clone` the repository and `cd` into it
2. Run `npm ci` to install the dependencies
3. Run `hugo server`

## Install The Theme

Create a new Hugo website:

```shell
hugo new site example.com
cd example.com/
```

Initialize the site as Hugo module

```shell
hugo mod init example.com
```

Add the following to the `config.toml` file:

```toml
[markup]
  # (Optional) To be able to use all Prism plugins, the theme enables unsafe
  # rendering by default
  #_merge = "deep"

[build]
  # The theme enables writeStats which is required for PurgeCSS
  _merge = "deep"

# This hopefully will be simpler in the future.
# See: https://github.com/schnerring/hugo-theme-gruvbox/issues/16
[module]
  [[module.imports]]
    path = "github.com/schnerring/hugo-theme-gruvbox"
  [[module.imports]]
    path = "github.com/schnerring/hugo-mod-json-resume"
    [[module.imports.mounts]]
      source = "data"
      target = "data"
    [[module.imports.mounts]]
      source = "layouts"
      target = "layouts"
    [[module.imports.mounts]]
      source = "assets/css/json-resume.css"
      target = "assets/css/critical/44-json-resume.css"
  [[module.mounts]]
    source = "assets"
    target = "assets"
  [[module.mounts]]
    source = "layouts"
    target = "layouts"
  [[module.mounts]]
    source = "static"
    target = "static"
  [[module.mounts]]
    source = "node_modules/prismjs"
    target = "assets/prismjs"
  [[module.mounts]]
    source = "node_modules/prism-themes/themes"
    target = "assets/prism-themes"
  [[module.mounts]]
    source = "node_modules/typeface-fira-code/files"
    target = "static/fonts"
  [[module.mounts]]
    source = "node_modules/typeface-roboto-slab/files"
    target = "static/fonts"
  [[module.mounts]]
    source = "node_modules/@tabler/icons/icons"
    target = "assets/tabler-icons"
```

Install the theme:

```shell
hugo mod get
```

Initialize the NPM `package.json` and install the dependencies:

```shell
hugo mod npm pack
npm install
```

Run Hugo:

```shell
hugo server
```

## Update The Theme

Update the Hugo modules:

```shell
hugo mod get -u
hugo mod tidy
```

Update the NPM dependencies:

```shell
hugo mod npm pack
npm install
```

## Colors

Two options are available to configure the theme colors:

- `defaultTheme`: `dark` or `light` (defaults to `light`)  
  Default theme color for when a user visits the site for the first time. OS or
  user preference override this setting.
  [See this comment for more details.](https://github.com/schnerring/hugo-theme-gruvbox/issues/34#issuecomment-1235870375)
- `themeColor`: `gray`, `red`, `green`, `yellow`, `blue`, `purple`, `aqua`, or
  `orange` (defaults to `blue`)  
  Theme color for things such as links, headings etc.
- `themeContrast`: `soft`, `medium`, or `hard` (defaults to `medium`)  
  Theme background color

## Prism

The theme allows customization of [Prism](https://prismjs.com/) via
`config.toml` parameters:

```toml
[params]
  [params.prism]
    languages = [
      "markup",
      "css",
      "clike",
      "javascript"
    ]
    plugins = [
      "normalize-whitespace",
      "toolbar",
      "copy-to-clipboard"
    ]
```

In my opinion, this is the coolest feature of the theme. Other Hugo themes
usually include a pre-configured version of Prism, which complicates updates and
change tracking, and clutters the theme's code base with third-party JavaScript.

The Prism theme is not configurable because of the integration with the dark
mode functionality. Toggling between color modes swaps the Prism theme between
[`gruvbox-dark`](https://github.com/PrismJS/prism-themes/blob/master/themes/prism-gruvbox-dark.css)
and
[`gruvbox-light`](https://github.com/PrismJS/prism-themes/blob/master/themes/prism-gruvbox-light.css)
from [github.com/PrismJS/prism-themes](https://github.com/PrismJS/prism-themes).

Check out the
[Prism showcase on the Demo site for examples](https://hugo-theme-gruvbox.schnerring.net/blog/prism-code-highlighting-showcase/)

### Explore Prism Features

After running `npm install`, explore Prism features like this:

```shell
# Languages
ls node_modules/prismjs/components

# Plugins
ls node_modules/prismjs/plugins
```

## Image Optimization

Images are optimized by default without requiring
[shortcodes](https://gohugo.io/content-management/shortcodes/). A
[custom render hook](https://gohugo.io/getting-started/configuration-markup#markdown-render-hooks)
does all the heavy lifting (see
[render-image.html](./layouts/_default/_markup/render-image.html)).

By default, the theme creates resized versions of images ranging from 300 to 700
pixels wide in increments of 100 pixels.

If the image format is not [WebP](https://en.wikipedia.org/wiki/WebP), the image
is converted. The original file format will serve as a fallback for browsers
that don't support the WebP format.

Note that only images that are part of the
[page bundle](https://gohugo.io/content-management/page-bundles/) are processed.
If served from the `static/` directory or external sources, the image will be
displayed but not be processed.

Additionally, all images are lazily loaded to save the bandwidth of your users.

### Configuration

The default quality is 75%. See the
[official Image Processing Config Hugo docs](https://gohugo.io/content-management/image-processing/#image-processing-config).
Change it by adding the following to the `config.toml` file:

```toml
[imaging]
  quality = 75
```

Change the resize behavior:

```toml
[params]
  [params.imageResize]
    min = 300
    max = 700
    increment = 100
```

### Captions

```markdown
![Alt text](image-url.jpg "Caption with **markdown support**")
```

[The demo site features examples you can look at](https://hugo-theme-gruvbox.schnerring.net/blog/image-optimization/).
I also use the theme for [my website](https://schnerring.net).

### Blog Post Covers

Add blog post covers by defining them in the
[front matter](https://gohugo.io/content-management/front-matter/) of your
posts:

```markdown
---
cover:
  src: my-blog-cover.jpg
  alt: A beautiful image containing interesting things
  caption: [Source](https://www.flickr.com/)
---
```

## Embed Video Files

Use the
[video shortcode](https://github.com/schnerring/hugo-theme-gruvbox/blob/main/layouts/shortcodes/video.html)
to embed your video files from
[Page Resources](https://gohugo.io/content-management/page-resources/).

With a page bundle looking like the following:

```text
embed-videos/
|-- index.md
|-- my-video.jpg
|-- my-video.mp4
|-- my-video.webm
```

You can embed `my-video` like this:

```markdown
{{< video src="my-video" autoplay="true" controls="false" loop="true" >}}
```

The shortcode looks for media files matching the filename `my-video*`. For each
`video` MIME type file, a `<source>` element is added. The first `image` MIME
type file is used as `poster` (thumbnail). It will render the following HTML:

```html
<video
  autoplay
  loop
  poster="/blog/embed-videos/my-video.jpg"
  width="100%"
  playsinline
>
  <source src="/blog/embed-videos/my-video.mp4" type="video/mp4" />
  <source src="/blog/embed-videos/my-video.webm" type="video/webm" />
</video>
```

You can set a Markdown `caption`, wrapping the `<video>` inside a `<figure`>.

Additionally, the shortcode allows you to set the following attributes:

| Attribute   | Default |
| ----------- | ------- |
| autoplay    | `false` |
| controls    | `true`  |
| height      |         |
| loop        | `false` |
| muted       | `true`  |
| preload     |         |
| width       | `100%`  |
| playsinline | `true`  |

[Learn more about the `<video>` attributes here.](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/video#attributes)

## SEO

Due to the
[European Copyright Directive](https://wayback.archive-it.org/12090/20210304045117/https://ec.europa.eu/digital-single-market/en/modernisation-eu-copyright-rules)
it is required to opt into displaying
[snippets](https://developers.google.com/search/docs/advanced/appearance/title-link?hl=en)
in search engine results.

By default, every page (except 404) includes the
`index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1`
robots meta value, opting into all snippet features.

You can override the robots meta value in the front matter of your pages:

```markdown
---
robots: noindex, nofollow
---
```

## Social Share Links

Configure social share links in the Hugo config like this:

```toml
[params]
  [[params.socialShare]]
    iconSuite = "simple-icon"
    iconName = "facebook"
    formatString = "https://www.facebook.com/sharer.php?u={url}"
  [[params.socialShare]]
    iconSuite = "simple-icon"
    iconName = "reddit"
    formatString = "https://reddit.com/submit?url={url}&title={title}"
  [[params.socialShare]]
    iconSuite = "tabler-icon"
    iconName = "mail"
    formatString = "mailto:?subject={title}&body={url}"
```

Use the `iconSuite` option to specify the icon suite used for the social share
link: `simple-icon` or `tabler-icon`. Select an icon from the suite with the
`iconName` option.

The `formatString` supports the following placeholders:

- `{url}` is replaced with the `.Permalink` of the post
- `{title}` is replaced with the `.Title` of the post

To enable social share links, set the following in the post's front matter:

```markdown
---
socialShare: true
---
```

Check out the
[Social Share URLs repo on GitHub](https://github.com/bradvin/social-share-urls)
for more format strings.

## Favicon

The favicons and [corresponding markup](./layouts/partials/head/favicons.html)
were generated with the free
[RealFaviconGenerator.net](https://realfavicongenerator.net/).

The easiest way to replace the default favicons is to generate them using
RealFaviconGenerator.net and put the generated files into the `static/`
directory.

## Extensibility

You can extend the theme by overriding the following partials in the
`layouts/partials` directory which by default are empty placeholder files:

- [`head/head_start.html`](./layouts/partials/head_start.html)  
  Custom HTML at the start of `<head>`
- [`head/head_end.html`](./layouts/partials/head_end.html)  
  Custom HTML at the end of `<head>`
- [`footer_end.html`](./layouts/partials/footer_end.html)  
  Custom HTML at the end of `<body>`
- [`comments.html`](./layouts/partials/comments.html)  
  Comments at the end of posts

### Example: Adding KaTeX Support to the Theme

[KaTeX](https://katex.org/) is a fast, easy-to-use JavaScript library for TeX
math rendering on the web. Let's add it to the theme via `npm`. First, add the
following to the `package.hugo.json` file:

```json
"dependencies": {
  "katex": "^0.16.8"
}
```

Then run `hugo mod npm pack` to sync the `package.hugo.json` dependencies with
`package.json`. Run `npm install` after. We then need to mount the
`node_modules/katex` folder into Hugo's virtual filesystem by adding the
following to the `config/_default/module.toml` file:

```toml
[[mounts]]
  source = "node_modules/katex"
  target = "assets/katex"
```

We can then add the following to `layouts/partials/head/head_end.html`:

<!-- prettier-ignore-start -->

```html
{{ if .Params.katex }}
  {{ $katexCSS := resources.Get "katex/dist/katex.min.css" }}
  <link
    rel="stylesheet"
    href="{{ $katexCSS }}"
    {{ if hugo.IsProduction }}
      integrity="{{ $katexCSS.Data.Integrity }}"
    {{ end }}
    crossorigin="anonymous"
  />

  {{ $katexJS := resources.Get "katex/dist/katex.min.js" }}
  <script
    defer
    src="{{ $katexJS.RelPermalink }}"
    {{ if hugo.IsProduction }}
      integrity="{{ $katexJS.Data.Integrity }}"
    {{ end }}
    crossorigin="anonymous"
  ></script>

  {{ $autoRender := resources.Get "katex/dist/contrib/auto-render.min.js" }}
  <script
    defer
    src="{{ $autoRender.RelPermalink }}"
    {{ if hugo.IsProduction }}
      integrity="{{ $autoRender.Data.Integrity }}"
    {{ end }}
    crossorigin="anonymous"
    onload="renderMathInElement(document.body);"
  ></script>
{{ end }}
```

<!-- prettier-ignore-end -->

The only thing left is enabling KaTeX in the front matter of our content:

```markdown
---
title: "Hello World"
description: "The first post of this blog"
date: 2021-03-14T15:00:21+01:00
draft: false
katex: true
---

I'm a .NET developer by trade, so let's say hello in C#!
```

## Configure the Tag Cloud

The theme comes with a tag cloud partial. It is included in the sidebar, but it
is disabled by default. If you wish to configure it, add the following to the
`[params]` section in the `config.toml` file:

```toml
[params.tagCloud]
  enable = true
  minFontSizeRem = 0.8
  maxFontSizeRem = 2.0
```

## Remove the Sidebar

If you want to get rid of the sidebar, add an empty `data/en.json` file with the
following content:

```json
{
  "$schema": "https://raw.githubusercontent.com/jsonresume/resume-schema/v1.0.0/schema.json",
  "basics": {},
  "work": [],
  "volunteer": [],
  "education": [],
  "awards": [],
  "certificates": [],
  "publications": [],
  "skills": [],
  "languages": [],
  "interests": [],
  "references": [],
  "projects": [],
  "meta": {
    "canonical": "https://raw.githubusercontent.com/jsonresume/resume-schema/master/resume.json",
    "version": "v1.0.0",
    "lastModified": "2017-12-24T15:53:00"
  }
}
```

## Extend CSS

The theme uses PostCSS with following plugins:

- [postcss-import](https://github.com/postcss/postcss-import)
- [postcss-url](https://github.com/postcss/postcss-url)
- [postcss-nesting](https://github.com/csstools/postcss-plugins/tree/main/plugins/postcss-nesting)
- [postcss-custom-media](https://github.com/postcss/postcss-custom-media)

Additionally the following plugins are used if building the site with
`hugo -e production`:

- [postcss-preset-env](https://github.com/csstools/postcss-plugins/tree/main/plugin-packs/postcss-preset-env)
- [cssnano](https://github.com/cssnano/cssnano) for minification
- [@fullhuman/postcss-purgecss](https://github.com/FullHuman/purgecss)

Inside the `assets/css` two folders exist, `critical` and `non-critical`. Files
inside `critical` are concatenated during build time and inlined into the
`<head>` element. The styles target mostly
[above the fold content](https://en.wikipedia.org/wiki/Above_the_fold#In_web_design).
Try to keep inline CSS to a minimum because it can't be cached and will be
inlined into every single page. Files inside `non-critical` are concatenated
into a single file and included as `<style>`. Most of the styles are in there.

Files are concatenated in lexicographic order of their file names. File names
start with two digits and a hyphen: `NN-`. The order of files might differ
between Linux and Windows, so using this convention improves cross-platform
compatibility.
[You might know this approach if you're familiar with Xorg](https://wiki.archlinux.org/title/Xorg#Using_.conf_files).

You can add new CSS files to the PostCSS pipeline like this:

- `critical/50-foo.css`
- `non-critical/05-bar.css`
- `non-critical/99-last.css`