First working draft of Style Guide for #1185 combines several commits

Initial dump of outline with some contents
Rearranged and built out more contents and links
More slight adjustments
Further touchups
Various continuing enhancements
Rearrangment and spiffup
Many more adjustments to draft style guide
Pushing up missing assets (thanks @david-waltermire-nist)
More touchups; pretty close to a complete draft 1 for #1185

docs/README.md

@@ -27,6 +27,8 @@ From the root directory of the repository, execute the following command to gene
 ./build/ci-cd/generate-model-documentation.sh
 ```
 
+Check the `ci-cd` directory for any similar scripts that may need to be run, such as `generate-specification-documentation.sh`.
+
 ## Using Hugo
 
 [Hugo](https://gohugo.io/) is a popular open source static site generator that is used to develop all of the content for the OSCAL website. It is a general-purpose framework that builds pages when the content is created or updated.

docs/assets/oscal-styleguide.css

@@ -0,0 +1,5 @@
+/* styleguide.css for Style Guide (demo) */
+
+.usa-sidenav { font-size: 0.95rem }
+
+.BigRed { font-size: 110%; font-weight: bold; color: #d54309 }

docs/content/reference/develop/_index.md

@@ -11,7 +11,7 @@ sidenav:
   debug: false
 oscal:
     type: "branch"
-    branch: "develop"
+    branch: "issue1185-styleguideA"
     revision: "develop"
     version: "develop"
 ---

docs/content/reference/develop/assessment-plan/_index.md

@@ -11,12 +11,12 @@ sidenav:
 ---
 
 <p><span class="usa-tag">Release Version</span> Latest Development Snapshot</p>
-<p><span class="usa-tag">Github</span> <a href="https://github.com/usnistgov/OSCAL">usnistgov/OSCAL</a> <span class="usa-tag">Branch</span> <a href="https://github.com/usnistgov/OSCAL/tree/develop">develop</a></p>
+<p><span class="usa-tag">Github</span> <a href="https://github.com/usnistgov/OSCAL">usnistgov/OSCAL</a> <span class="usa-tag">Branch</span> <a href="https://github.com/usnistgov/OSCAL/tree/issue1185-styleguideA">issue1185-styleguideA</a></p>
 
 The following reference documentation is available for the OSCAL Assessment Plan model.
 
 - **[Conceptual Overview](/concepts/layer/assessment/assessment-plan/):** Provides a high-level overview of the model's intended purpose and role in the [OSCAL architecture](/concepts/layer/). Describes the model's purpose, target audience, and key concepts.
 - **Outline ([JSON/YAML](json-outline/), [XML](xml-outline/)):** Provides a brief listing of the model's information items organized hierarchically. Useful for understanding the structure and basic syntax of the model in a given format.
 - **Reference ([JSON/YAML](json-reference/), [XML](xml-reference/)):** Provides a detailed description of the structure and syntax for the model's information items organized hierarchically. Useful for understanding how to use information items within the model in the given format. 
 - **Index ([JSON/YAML](json-index/), [XML](xml-index/)):** Provides a listing of the model's information items organized by where they are used.
-- **Definitions ([JSON/YAML](json-definitions/), [XML](xml-definitions/)):** Provides a reference for the XML Schema types and JSON Schema definitions derived from this model's [metaschema](https://github.com/usnistgov/OSCAL/blob/develop/src/metaschema/oscal_assessment-plan). A metaschema is used to [express the model](/concepts/layer/overview/#modeling-approach) in a format agnostic way, that is then used to generate the XML and JSON Schema, XML <-> JSON content converters, and this reference documentation.
+- **Definitions ([JSON/YAML](json-definitions/), [XML](xml-definitions/)):** Provides a reference for the XML Schema types and JSON Schema definitions derived from this model's [metaschema](https://github.com/usnistgov/OSCAL/blob/issue1185-styleguideA/src/metaschema/oscal_assessment-plan). A metaschema is used to [express the model](/concepts/layer/overview/#modeling-approach) in a format agnostic way, that is then used to generate the XML and JSON Schema, XML <-> JSON content converters, and this reference documentation.

docs/content/reference/develop/assessment-plan/json-index.md

@@ -10,7 +10,7 @@ toc:
   headingselectors: "h1.toc1"
 ---
 
-The following is an index of each JSON property used in the [JSON format](https://github.com/usnistgov/OSCAL/blob/develop/json/schema/oscal_assessment-plan_schema.json) for this [model](/concepts/layer/assessment/assessment-plan/). Each entry in the index lists all uses of the given property in the format, which is linked to the corresponding entry in the [JSON Format Reference](../json-reference/). Each entry also lists the formal name for the definition which is linked to the corresponding JSON definition in the [JSON Format Metaschema Reference](../json-definitions/).
+The following is an index of each JSON property used in the [JSON format](https://github.com/usnistgov/OSCAL/blob/issue1185-styleguideA/json/schema/oscal_assessment-plan_schema.json) for this [model](/concepts/layer/assessment/assessment-plan/). Each entry in the index lists all uses of the given property in the format, which is linked to the corresponding entry in the [JSON Format Reference](../json-reference/). Each entry also lists the formal name for the definition which is linked to the corresponding JSON definition in the [JSON Format Metaschema Reference](../json-definitions/).
 
 <!-- DO NOT REMOVE. Generated text below -->
 {{< rawhtml >}}

docs/content/reference/develop/assessment-plan/json-outline.md

@@ -10,7 +10,7 @@ sidenav:
 
 ---
 
-The following outline is a representation of the [JSON format](https://github.com/usnistgov/OSCAL/blob/develop/json/schema/oscal_assessment-plan_schema.json) for this [model](/concepts/layer/assessment/assessment-plan/). For each property, the name links to the corresponding entry in the [JSON Format Reference](../json-reference/). The cardinality and data type are also provided for each property where appropriate.
+The following outline is a representation of the [JSON format](https://github.com/usnistgov/OSCAL/blob/issue1185-styleguideA/json/schema/oscal_assessment-plan_schema.json) for this [model](/concepts/layer/assessment/assessment-plan/). For each property, the name links to the corresponding entry in the [JSON Format Reference](../json-reference/). The cardinality and data type are also provided for each property where appropriate.
 
 <!-- DO NOT REMOVE. Generated text below -->
 {{< rawhtml >}}
@@ -56,7 +56,7 @@ The following outline is a representation of the [JSON format](https://github.co
                                  <p class="OM-line"><a class="OM-name" href="../json-reference/#/assessment-plan/metadata/revisions/last-modified">last-modified</a> <span class="OM-cardinality">[0 or 1]</span>: <span class="OM-datatype"><a href="/reference/datatypes/#datetime-with-timezone">dateTime-with-timezone</a></span><span class="OM-lit">,</span></p>
                               </div>
                               <div class="OM-entry">
-                                 <p class="OM-line"><a class="OM-name" href="../json-reference/#/assessment-plan/metadata/revisions/version">version</a> <span class="OM-cardinality">[0 or 1]</span>: <span class="OM-datatype"><a href="/reference/datatypes/#string">string</a></span><span class="OM-lit">,</span></p>
+                                 <p class="OM-line"><a class="OM-name" href="../json-reference/#/assessment-plan/metadata/revisions/version">version</a> <span class="OM-cardinality">[1]</span>: <span class="OM-datatype"><a href="/reference/datatypes/#string">string</a></span><span class="OM-lit">,</span></p>
                               </div>
                               <div class="OM-entry">
                                  <p class="OM-line"><a class="OM-name" href="../json-reference/#/assessment-plan/metadata/revisions/oscal-version">oscal-version</a> <span class="OM-cardinality">[0 or 1]</span>: <span class="OM-datatype"><a href="/reference/datatypes/#string">string</a></span><span class="OM-lit">,</span></p>