CSS Requirements for RFCs

The HTML format for RFCs, described in assigns style guidance to an RFC Editor-defined Cascading Style Sheet (CSS). This CSS will be embedded in the published HTML, and may be overridden by a locally defined CSS as desired. The embedded, default CSS as included by the RFC Editor is expected to take into account accessibility needs and be built along a responsive design model. This document describes the requirements for the default CSS used by the RFC Editor. Unless called out otherwise, any styling provided for these classes must not alter the natural language content in any visible way. Many of these classes are provided to mark the elements semantically: elements using them should simply inherit their surrounding styling. Exceptions are called out below. A class is identified for Internet Drafts, such that certain features found only in I-Ds may be made distinct in some fashion within those drafts. The requirements will only be applied to HTML documents published by the RFC Editor as per . The details described in this document are expected to change based on experience gained in implementing the RFC production center's toolset. Revised documents will be published capturing those changes as the toolset is completed. Other implementers must not expect those changes to remain backwards-compatible with the details described this document.

RFCs must be adaptable to a wide variety of devices and displays, accessible to assisted readers, and printable.

Support the display of the semantic HTML described in . Follow best practice for accessibility, as defined by the W3C's "Best Practices for Authoring HTML" . Follow best practice for mobile devices, as defined by the W3C's "Best Practices for Authoring HTML." Allow for a broad range of internationalized scripts.

The document header must be at the top of the page and include all information described in the "Style Guide" and "RFC Streams, Headers, and Boilerplates"

The body of the document must conform to the following: Examples and code blocks must be in a fixed-width font ASCII art must be in a fixed-width font Reflow the text as the screen gets smaller and limit max width Block quotes must be indented Tables must allow for distinct header rows Paragraphs should include a hover-over paragraph identifier All anchor tags and URLs should be clearly distinguished as links, for example through the use of color and/or text decoration, following appropriate accessibility standards.

Default to a sans-serif font family with broad Unicode support for web browser viewing. Default to a serif font family with broad Unicode support for printing. A fixed-width font must be used for code and artwork-tagged sections. All fonts should be publicly licensed and supported by all major web browsers.

The CSS must include support for a printer-friendly output. The print rules should be a part of the embedded style sheet; consumers of an RFC may develop their own print-specific style sheet as desired.

Lists should provide ample whitespace between list elements for legibility unless a ‘compact’ class is specified (e.g., .dlcompact, .ulcompact, .olcompact).

This section describes the CSS classes that result in specific changes to the natural language content of a document. A full list of available classes, not including basic selectors, are included in "Appendix A".

These classes will mostly be styled as part of .artwork. Specific classes may include '.art-ascii-art' and '.art-svg'. Artwork will be held in its own block of space, centered in the page flow, and will not float. Images shoul dhave a max width of 100% so views will scale properly across a variety of screens and devices.

Must use a mono-spaced font.

No visible changes to the natural language content; keep in default style. Note that such images are not currently allowed in RFCs.

A comment within an I-D; should be visually distinct. For I-Ds only; not for RFCs.

Do not use the standard hanging indent for a definition list; align terms and definitions along left side.

Use less spacing on a definition list than the default.

Hide from visible content.

Standard link formatting (underlined, change in color).

Hide from visible content.

Notes should be emphasized and distinct from normal paragraph text.

An rfceditor note may be added after the standard boilerplage. It should be visually distinct to highlight final removal of the note by the RFC Editor.

Use less spacing on a numbered list than the default.

If the style attribute from the source XML contains a percent sign, a particular style setting will be required to make this setting behave like an HTML ordered list.

Pilcrows, when used as described in draft-hildebrand-html-rfc, should appear at the end of the paragraph, artwork, or sourcecode segment.

Should be clearly distinguished as links.

Hide from visible content.

Code examples or components should be in a fixed-width font if the human language used has an available fixed-width font option, and should be visually distinct. If no fixed-width font is available, use the default font for that human language.

Example: lang-c

should be clearly distinguished using an indented, ordered list with the list style set to 'none', allowing for hyperlinked, in-line dotted number notation (e.g., 1., 1.1., 1.1.1.).

No visible changes to the natural language content; keep in default style.

Use less spacing on a bulleted list than the default.

Should be clearly distinguished as links.

No visible changes to the natural language content; keep in default style.

Should be clearly distinguished as links.

Security vulnerabilities can be introduced through the CSS. How much detail do we need to go into here to say "don't do foolish things and introduce security issues?"

This draft contains no action for IANA

With many thanks to the RFC Format Design Team for their efforts in making this transition successful: Nevil Brownlee (ISE), Tony Hansen, Joe Hildebrand, Paul Hoffman, Ted Lemon, Julian Reschke, Adam Roach, Alice Russo, Robert Sparks (Tools Team liaison), and Dave Thaler. Additional thanks to Arlen Johnson of Spherical Cow Group, LLC, for his assistance in clarifying the requirements in more CSS designer-friendly language.

To be removed before publication

Moved full list of classes to Appendix; only discussed classes that will have visible changes to the text in the body Introduction: text regarding expected future changes added. Body: added text regarding anchors and tags; this text also applied to .relref, .url, .xref Artwork: clarified non-floating behavior of artwork List behavior: clarified the behavior of .ulcompact, .olcompact, and .dlcompact as distinct from default list behavior; clarified behavior of .dlparallel Note: clarified text around behavior of notes RFC: added additional class to allow the CSS to distinguish between RFCs and Internet Drafts if desired TOC: clarified text around behavior of table of contents

.adr .annotation .anticomma .artwork .art-ascii-art .art-logo .art-svg .ascii .author .authors .bcp14 .city .comma .compact .country-name .cref .crefAnchor .cref-source .dlparallel .dlcompact .docinfo .email .eref .finalized .fn .index .indexChar .indexComma .indexIndex .indexItem .indexPrimary .indexSubItem .initial .iref .irefItem .irefRefs .irefSubItem .label .locality .namerole .note .rfceditor-remove .olcompact .olpercent .org .organization .pilcrow .postal-code .published .refauthor .refcontent .reference .referencegroup .region .relref .rendered .RFC .role .self-ref .series .seriesInfo .sourcecode .lang- .street-address .status .street-address .surname .tel .toc .type .ulcompact .url .workgroup .xref .vcard