Cascading Style Sheets (CSS) Requirements for RFCs

The HTML format for RFCs assigns style guidance to a Cascading Style Sheet (CSS) specifically defined for the RFC Series. The embedded, default CSS as included by the RFC Editor is expected to take into account accessibility needs and to be built along a responsive design model. This document describes the requirements for the default CSS used by the RFC Editor. The class names are based on the classes defined in "HTML for RFCs" (RFC 7992).¶

This document is not an Internet Standards Track specification; it is published for informational purposes.¶

This document is a product of the Internet Architecture Board (IAB) and represents information that the IAB has deemed valuable to provide for permanent record. It represents the consensus of the Internet Architecture Board (IAB). Documents approved for publication by the IAB are not a candidate for any level of Internet Standard; see Section 2 of RFC 7841.¶

Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at http://www.rfc-editor.org/info/rfc7993.¶

Copyright (c) 2016 IETF Trust and the persons identified as the document authors. All rights reserved.¶

This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document.¶

The HTML format for RFCs, described in [RFC7992], assigns style guidance to a Cascading Style Sheet (CSS) specifically defined for the RFC Series. This CSS will be embedded in the published HTML, and it 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 to 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 listed 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 [RFC7990].¶

The details included in this document are expected to change based on experience gained in implementing the new publication toolsets. Revised documents will be published capturing those changes as the toolsets are completed. Other implementers must not expect those changes to remain backwards compatible with the details included in 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 [RFC7992].
• Follow best practice for accessibility, as defined by the W3C's "Best Practices for Authoring HTML" [HTMLBP].
• 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 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, is included in Appendix A.¶

Security vulnerabilities can be introduced through the CSS, as with CSS injection attacks [CSSATTACK]. In order to avoid or mitigate any attack vectors here, the CSS used must comply with the current CSS Specifications from the W3C.¶

This section lists all the CSS classes. Except for those also listed in Section 7, none of these result in specific changes to the natural language content of a document.¶

• .adr
• .alignCenter
• .alignRight
• .annotation
• .artwork
  • .art-ascii-art
  • .art-logo
  • .art-svg
• .ascii
• .author
• .authors
• .bcp14
• .center
• .city
• .compact
• .country-name
• .cref
• .crefAnchor
• .crefSource
• .dlCompact
• .dlHanging
• .dlParallel
• .docInfo
• .ears
• .email
• .eref
• .finalized
• .fn
• .index
• .indexChar
• .indexIndex
• .indexItem
• .indexPrimary
• .indexSubItem
• .initial
• .iref
• .irefItem
• .irefRefs
• .irefSubItem
• .label
• .left
• .locality
• .nameRole
• .note
  • .rfcEditorRemove
• .olCompact
• .olPercent
• .org
• .organization
• .pilcrow
• .postal-code
• .published
• .refContent
• .refDate
• .refInstance
• .refTitle
• .reference
• .region
• .relref
• .rendered
• .RFC
• .rfcEditorRemove
• .right
• .role
• .selfRef
• .series
• .seriesInfo
• .sourcecode
  • .lang-*
• .street-address
• .status
• .street-address
• .surname
• .tel
• .toc
• .type
• .ulCompact
• .ulEmpty
• .url
• .workgroup
• .xref
• .vcard

The IAB members at the time this memo was approved were (in alphabetical order): ¶

• Jari Arkko
• Ralph Droms
• Ted Hardie
• Joe Hildebrand
• Russ Housley
• Lee Howard
• Erik Nordmark
• Robert Sparks
• Andrew Sullivan
• Dave Thaler
• Martin Thomson
• Brian Trammell
• Suzanne Woolf

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.¶