Move SCSS to styles folder

CONTRIBUTING.md

@@ -25,6 +25,7 @@ The XRPL Dev Portal provides comprehensive documentation of the the XRP Ledger,
     - [content/\_snippets/](content/_snippets/) - Reusable chunks of Markdown text that are included in other content files, using the Dactyl preprocessor.
 - [img/](img/) - Images used by the documentation contents.
 - [tool/](tool/) - Templates, style-checker rules, and other scripts.
+- [styles/](styles/) - Source files (SCSS) to generate the CSS files in the assets folder.
 - [`dactyl-config.yml`](dactyl-config.yml) - Main config file, which contains the metadata for all the docs. For information on our conventions, see [Config Formatting](#config-formatting).
 
 ## Requirements for a Successful Pull Request

styles/README.md

@@ -0,0 +1,37 @@
+# XRPL Styles
+
+This folder contains the source files for the XRP Ledger Dev Portal CSS. The combined, minified version of these styles is `assets/css/devportal.css`.
+
+## Prerequisites
+
+To edit or modify these styles, you need to install Bootstrap's SCSS files. The included `package.json` file should help you do this using [Yarn](https://yarnpkg.com/) or [NPM](https://www.npmjs.com/). For example, if you have Yarn installed, run the following command from this directory:
+
+```sh
+$ yarn
+```
+
+You also need a SASS/SCSS compiler; the dependency file should install [node-sass](https://www.npmjs.com/package/sass) and a script for running it by default. You can also use [`sassc`](https://github.com/sass/sassc/), which can be installed using your system's package manager (Linux) or Homebrew (macOS).
+
+## Building
+
+To build the output file using node-sass, run the following command from this directory:
+
+```sh
+$ yarn run build-css
+```
+
+(You could also use `npm` instead of `yarn`.)
+
+To build the output file using sassc, run the following command from this directory:
+
+```sh
+$ sassc xrpl.scss -t compressed -m > ../assets/css/devportal.css
+```
+
+You can omit the `-m` (include source map) to reduce the output file size. It provides useful information when debugging styles, about which original file specific rules came from.
+
+## Files
+
+`xrpl.scss` is the master file that includes all the other, `_`-prefixed SCSS files. This file also defines common colors and other utilities.
+
+Files prefixed with `_dactyl-` are pulled from the Dactyl built-in styles. You should edit these files as little as possible so that they we can pull in updates from upstream as easily as possible. ***TODO: Publish these files on NPM so they can be imported/installed the same way the Bootstrap styles are.***

styles/package.json

@@ -0,0 +1,9 @@
+{
+  "devDependencies": {
+    "bootstrap": "^4.5.0",
+    "node-sass": "^4.14.1"
+  },
+  "scripts": {
+    "build-css": "node-sass --include-path scss xrpl.scss ../assets/css/devportal.css --output-style compressed"
+  }
+}