+Accessible documents allow everyone to access information equally.
+This also improves the user experience. To improve accessibility, use
+clear headings, descriptive alt text, and high colour contrast. This
+supports assistive technologies and aids users with visual or hearing
+impairments.
+
+Make your information easy to read by using clear tables and simple
+lists. These formats act like a map, helping your reader navigate
+complex data quickly.
+
+Give every diagram and table a descriptive title. For technical
+drawings like engineering diagrams, add call-outs to explain key
+parts. These labels guide the eye and clarify how systems connect.
+
+Follow the other design rules in this document to improve your layout.
+Use consistent fonts, proper spacing, and organised headings. These
+elements work together to create a professional look. Structured
+formatting helps lessen eye strain and keeps readers focused on the
+content.
+
+=== Admonitions
+
+Pick the admonition type by what happens to the reader who ignores the
+box, not by how much we want their attention. Overusing WARNING trains
+readers to skip all five.
+
+.Admonition types
+[cols="1,3,2",options="header"]
+|===
+| Type | Use when | Cost of ignoring it
+| NOTE | Extra context that helps but isn't needed to finish the task. | Nothing breaks.
+| TIP | A faster or cleaner way to do what the reader is already doing. | Nothing breaks, the reader uses a slower method.
+| IMPORTANT | A step or condition the reader must not skip. | The task fails or gives the wrong result.
+| CAUTION | An action that can lose data, break a running server, or need manual recovery. | Recoverable damage.
+| WARNING | An action that can lock out access, expose credentials, or take down production. | Serious or hard to reverse damage.
+|===
+
+Keep an admonition to three sentences. Anything longer belongs in body
+text under its own heading.
+
+Never stack two admonitions together, as readers skip both. Never open
+a section with an admonition, because the reader has no context yet
+for the thing they're being warned about.
+
+=== Capitalisation
+
+Use *Title Case* for all Table of Contents (TOC) entries to ensure
+clear organisation.
+
+Use *Title Case* for your main titles and top-level headings, such as
+H1 and H2. This consistency helps readers navigate your document like
+a map. Ensure navigation panels match the H1 and H2 headings on
+selected pages to avoid confusing users.
+
+Use *Sentence case* for all smaller headings from H3 to H6. This style
+follows a regular sentence. Only the first word and proper nouns are
+capitalised. This shows the reader that these sections provide
+supporting details, not main topics. The documentation needs varying
+heading styles to guide the reader through the content.
+
+[#collapsible]
+=== Collapsible text
+
+Use a collapsible block for very large code snippets, programming
+examples, debug outputs, or anything longer than 20 lines. This allows
+us to place more information on one or two pages, and readers can
+select exactly the information they need by expanding sections.
+
+A collapsible block is an example block (`====` delimiters) marked
+with `[%collapsible]`:
+
+----
+.Server startup output
+[%collapsible]
+====
+FreeRADIUS Version 4.0.0
+Copyright (C) 1999-2026 The FreeRADIUS server project and contributors
+====
+----