Give helpers folder an index.scss, migrate ratio helper to aspect-ratio utility

site/data/sidebar.yml

@@ -107,7 +107,6 @@
     - title: Focus ring
     - title: Icon link
     - title: Position
-    - title: Ratio
     - title: Stacks
     - title: Stretched link
     - title: Text truncation
@@ -119,6 +118,7 @@
   icon_color: red
   pages:
     - title: API
+    - title: Aspect ratio
     - title: Background
     - title: Borders
     - title: Colors

site/src/content/docs/utilities/aspect-ratio.mdx

@@ -1,46 +1,45 @@
 ---
-title: Ratios
+title: Aspect Ratio
 description: Use generated pseudo elements to make an element maintain the aspect ratio of your choosing. Perfect for responsively handling video or slideshow embeds based on the width of the parent.
 toc: true
 ---
 
-## About
-
-Use the ratio helper to manage the aspect ratios of external content like `<iframe>`s, `<embed>`s, `<video>`s, and `<object>`s. These helpers also can be used on any standard HTML child element (e.g., a `<div>` or `<img>`). Styles are applied from the parent `.ratio` class directly to the child.
-
-Aspect ratios are declared in a Sass map and included in each class via CSS variable, which also allows [custom aspect ratios](#custom-ratios).
+Use the ratio utility to manage the aspect ratios of content like `<iframe>`s, `<embed>`s, `<video>`s, and `<object>`s. These helpers also can be used on any standard HTML child element (e.g., a `<div>` or `<img>`). Customize the available aspect ratios with the Sass variable or the utility API.
 
 <Callout>
-**Pro-Tip!** You don’t need `frameborder="0"` on your `<iframe>`s as we override that for you in [Reboot]([[docsref:/content/reboot]]).
+**Pro-Tip!** You don't need `frameborder="0"` on your `<iframe>`s as we override that for you in [Reboot]([[docsref:/content/reboot]]).
 </Callout>
 
 ## Example
 
-Wrap any embed, like an `<iframe>`, in a parent element with `.ratio` and an aspect ratio class. The immediate child element is automatically sized thanks to our universal selector `.ratio > *`.
+Add your ratio utility to the element you want to modify, like an `<iframe>`. Ratio utilities also pair well with any width utilities, as shown below.
 
-<Example code={`<div class="ratio ratio-16x9">
-    <iframe src="https://www.youtube.com/embed/zpOULjyy-n8?rel=0" title="YouTube video" allowfullscreen></iframe>
-  </div>`} />
+<Example code={`<iframe class="w-100 ratio-16x9" src="https://www.youtube.com/embed/zpOULjyy-n8?rel=0" title="YouTube video" allowfullscreen></iframe>`} />
 
 ## Aspect ratios
 
 Aspect ratios can be customized with modifier classes. By default the following ratio classes are provided:
 
-<Example class="bd-example-ratios" code={`<div class="ratio ratio-1x1">
+<Example class="bd-example-ratios" code={`<div class="ratio-auto">
+    <div>Auto</div>
+  </div>
+  <div class="w-25 ratio-1x1">
     <div>1x1</div>
   </div>
-  <div class="ratio ratio-4x3">
+  <div class="w-50 ratio-4x3">
     <div>4x3</div>
   </div>
-  <div class="ratio ratio-16x9">
+  <div class="w-75 ratio-16x9">
     <div>16x9</div>
   </div>
-  <div class="ratio ratio-21x9">
+  <div class="w-100 ratio-21x9">
     <div>21x9</div>
   </div>`} />
 
 ## Custom ratios
 
+{/* mdo-do: do we bring these back?
+
 Each `.ratio-*` class includes a CSS custom property (or CSS variable) in the selector. You can override this CSS variable to create custom aspect ratios on the fly with some quick math on your part.
 
 For example, to create a 2x1 aspect ratio, set `--bs-aspect-ratio: 50%` on the `.ratio`.
@@ -62,10 +61,10 @@ This CSS variable makes it easy to modify the aspect ratio across breakpoints. T
 <Example class="bd-example-ratios bd-example-ratios-breakpoint" code={`<div class="ratio ratio-4x3">
     <div>4x3, then 2x1</div>
   </div>`} />
+*/}
 
+## Sass map
 
-## Sass maps
-
-Within `_variables.scss`, you can change the aspect ratios you want to use. Here’s our default `$ratio-aspect-ratios` map. Modify the map as you like and recompile your Sass to put them to use.
+Within `_variables.scss`, you can change the aspect ratios you want to use. Here's our default `$aspect-ratios` map. Modify the map as you like and recompile your Sass to put them to use.
 
 <ScssDocs name="aspect-ratios" file="scss/_variables.scss" />

site/src/scss/_component-examples.scss

@@ -181,29 +181,17 @@
 
 // Ratio helpers
 .bd-example-ratios {
-  .ratio {
-    display: inline-block;
-    width: 10rem;
+  [class*="ratio"] {
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    margin-bottom: 1rem;
     color: var(--bs-secondary-color);
     background-color: var(--bs-tertiary-bg);
     border: var(--bs-border-width) solid var(--bs-border-color);
-
-    > div {
-      display: flex;
-      align-items: center;
-      justify-content: center;
-    }
   }
 }
-.bd-example-ratios-breakpoint {
-  .ratio-4x3 {
-    width: 16rem;
 
-    @include media-breakpoint-up(md) {
-      --bs-aspect-ratio: 50%; // 2x1
-    }
-  }
-}
 
 .bd-example-offcanvas {
   .offcanvas {