Add Sass docs (variables, mixins, and loops) to most pages (#32747)

* WIP: Mention variables, mixins, and loops in docs

* Add Sass sections to component pages

* add sass docs for forms and content

* Update buttons.md

* Remove empty mixins sections

* Massive update to utilities and some consistency changes

Co-authored-by: XhmikosR <xhmikosr@gmail.com>

site/content/docs/5.0/forms/checks-radios.md

@@ -269,3 +269,9 @@ Different variants of `.btn`, such at the various outlined styles, are supported
 <input type="radio" class="btn-check" name="options-outlined" id="danger-outlined" autocomplete="off">
 <label class="btn btn-outline-danger" for="danger-outlined">Danger radio</label>
 {{< /example >}}
+
+## Sass
+
+### Variables
+
+{{< scss-docs name="form-check-variables" file="scss/_variables.scss" >}}

site/content/docs/5.0/forms/floating-labels.md

@@ -100,3 +100,9 @@ When working with the Bootstrap grid system, be sure to place form elements with
   </div>
 </div>
 {{< /example >}}
+
+## Sass
+
+### Variables
+
+{{< scss-docs name="form-floating-variables" file="scss/_variables.scss" >}}

site/content/docs/5.0/forms/form-control.md

@@ -130,3 +130,17 @@ Learn more about [support for datalist elements](https://caniuse.com/datalist).
   <option value="Chicago">
 </datalist>
 {{< /example >}}
+
+## Sass
+
+### Variables
+
+`$input-*` are shared across most of our form controls (and not buttons).
+
+{{< scss-docs name="form-input-variables" file="scss/_variables.scss" >}}
+
+`$form-label-*` and `$form-text-*` are for our `<label>`s and `.form-text` component.
+
+{{< scss-docs name="form-label-variables" file="scss/_variables.scss" >}}
+
+{{< scss-docs name="form-text-variables" file="scss/_variables.scss" >}}

site/content/docs/5.0/forms/input-group.md

@@ -308,3 +308,9 @@ Input groups include support for custom selects and custom file inputs. Browser
   <button class="btn btn-outline-secondary" type="button" id="inputGroupFileAddon04">Button</button>
 </div>
 {{< /example >}}
+
+## Sass
+
+### Variables
+
+{{< scss-docs name="input-group-variables" file="scss/_variables.scss" >}}

site/content/docs/5.0/forms/overview.md

@@ -142,3 +142,13 @@ For situations where it's not possible to include a visible `<label>` or appropr
 If none of these are present, assistive technologies may resort to using the `placeholder` attribute as a fallback for the accessible name on `<input>` and `<textarea>` elements. The examples in this section provide a few suggested, case-specific approaches.
 
 While using visually hidden content (`.visually-hidden`, `aria-label`, and even `placeholder` content, which disappears once a form field has content) will benefit assistive technology users, a lack of visible label text may still be problematic for certain users. Some form of visible label is generally the best approach, both for accessibility and usability.
+
+## Sass
+
+Many form variables are set at a general level to be re-used and extended by individual form components. You'll see these most often as `$btn-input-*` and `$input-*` variables.
+
+### Variables
+
+`$btn-input-*` variables are shared global variables between our [buttons]({{< docsref "/components/buttons" >}}) and our form components. You'll find these frequently reassigned as values to other component-specific variables.
+
+{{< scss-docs name="input-btn-variables" file="scss/_variables.scss" >}}

site/content/docs/5.0/forms/range.md

@@ -41,3 +41,9 @@ By default, range inputs "snap" to integer values. To change this, you can speci
 <label for="customRange3" class="form-label">Example range</label>
 <input type="range" class="form-range" min="0" max="5" step="0.5" id="customRange3">
 {{< /example >}}
+
+## Sass
+
+### Variables
+
+{{< scss-docs name="form-range-variables" file="scss/_variables.scss" >}}

site/content/docs/5.0/forms/select.md

@@ -73,3 +73,9 @@ Add the `disabled` boolean attribute on a select to give it a grayed out appeara
   <option value="3">Three</option>
 </select>
 {{< /example >}}
+
+## Sass
+
+### Variables
+
+{{< scss-docs name="form-select-variables" file="scss/_variables.scss" >}}

site/content/docs/5.0/forms/validation.md

@@ -349,18 +349,34 @@ If your form layout allows it, you can swap the `.{valid|invalid}-feedback` clas
 </form>
 {{< /example >}}
 
-## Customizing
+## Sass
 
-Validation states can be customized via Sass with the `$form-validation-states` map. Located in our `_variables.scss` file, this Sass map is how we generate the default `valid`/`invalid` validation states. Included is a nested map for customizing each state's color, icon, tooltip color, and focus shadow. While no other states are supported by browsers, those using custom styles can easily add more complex form feedback.
+### Variables
 
-Please note that we do not recommend customizing these values without also modifying the `form-validation-state` mixin.
+{{< scss-docs name="form-feedback-variables" file="scss/_variables.scss" >}}
 
-This is the Sass map from `_variables.scss`. Override this and recompile your Sass to generate different states:
+### Mixins
+
+Two mixins are combined together, through our [loop](#loop), to generate our form validation feedback styles.
+
+{{< scss-docs name="form-validation-mixins" file="scss/mixins/_forms.scss" >}}
+
+### Map
+
+This is the validation Sass map from `_variables.scss`. Override or extend this to generate different or additional states.
 
 {{< scss-docs name="form-validation-states" file="scss/_variables.scss" >}}
 
 Maps of `$form-validation-states` can contain three optional parameters to override tooltips and focus styles.
 
-This is the loop from `forms/_validation.scss`. Any modifications to the above Sass map will be reflected in your compiled CSS via this loop:
+### Loop
+
+Used to iterate over `$form-validation-states` map values to generate our validation styles. Any modifications to the above Sass map will be reflected in your compiled CSS via this loop.
 
 {{< scss-docs name="form-validation-states-loop" file="scss/forms/_validation.scss" >}}
+
+### Customizing
+
+Validation states can be customized via Sass with the `$form-validation-states` map. Located in our `_variables.scss` file, this Sass map is how we generate the default `valid`/`invalid` validation states. Included is a nested map for customizing each state's color, icon, tooltip color, and focus shadow. While no other states are supported by browsers, those using custom styles can easily add more complex form feedback.
+
+Please note that **we do not recommend customizing `$form-validation-states` values without also modifying the `form-validation-state` mixin**.