Draft improvements from assistant conversations: sidebar/font CSS and OpenAPI URL note

api-playground/openapi-setup.mdx

@@ -343,7 +343,7 @@
 
 Add an `openapi` field to any navigation element in your `docs.json` to automatically generate pages for OpenAPI endpoints. You can control where these pages appear in your navigation structure, as dedicated API sections or with other pages.
 
-The `openapi` field accepts either a path in your docs repo or a URL to a hosted OpenAPI document.
+The `openapi` field accepts either a path in your docs repo or a URL to a hosted OpenAPI document. Hosted specs must be reachable from the public internet; `localhost` URLs and private hosts cannot be fetched at build time.
 
 <Tip>
   When you use a URL for your OpenAPI spec, changes to the spec don't trigger a Git push, so your docs won't redeploy automatically. To keep your docs in sync, call the [Trigger deployment](/api/update/trigger) API endpoint in the same CI action that generates or updates your spec. This way your docs update automatically without needing to manually trigger a deployment from the dashboard.

customize/custom-scripts.mdx

@@ -343,6 +343,49 @@
   </Accordion>
 </AccordionGroup>
 
+### Common customizations
+
+Mintlify's appearance settings in `docs.json` do not include options for sidebar width, font size, or other fine-grained layout controls. To adjust these, target the selectors above with custom CSS.
+
+<AccordionGroup>
+  <Accordion title="Change the sidebar width">
+    Override the sidebar container width to make the sidebar narrower or wider. The main content area adjusts automatically.
+
+    ```css
+    #sidebar {
+      width: 240px;
+    }
+    ```
+  </Accordion>
+  <Accordion title="Change the sidebar font size">
+    The `fonts` field in `docs.json` sets font family and weight, but not font size. Use custom CSS to resize sidebar text.
+
+    ```css
+    #sidebar-content {
+      font-size: 0.8rem;
+    }
+    ```
+  </Accordion>
+  <Accordion title="Change the body font size">
+    Resize the main content area without changing headings.
+
+    ```css
+    #content-area {
+      font-size: 0.95rem;
+    }
+    ```
+  </Accordion>
+  <Accordion title="Hide the sign-in or CTA button">
+    Prefer removing `navbar.primary` from `docs.json` when possible. If you need to hide the button conditionally with CSS, target its ID:
+
+    ```css
+    #topbar-cta-button {
+      display: none;
+    }
+    ```
+  </Accordion>
+</AccordionGroup>
+
 ## Custom JavaScript
 
 Custom JS lets you add custom executable code globally. It is the equivalent of adding a `<script>` tag with JS code into every page.
@@ -350,7 +393,7 @@
 Mintlify includes any `.js` file inside your content directory on every page of your documentation site. Custom JavaScript files run after the page becomes interactive. You cannot scope them to specific pages. For example, you can add the following `ga.js` file to enable [Google Analytics](https://marketingplatform.google.com/about/analytics) across the entire documentation.
 
 ```js
 window.dataLayer = window.dataLayer || [];
 function gtag() {
   dataLayer.push(arguments);
 }