Wiki source code of HTML & CSS Code Style

Last modified by Lucas Charpentier on 2026/03/11 10:23

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1 {{box cssClass="floatinginfobox" title="**Contents**"}}
2 {{toc/}}
3 {{/box}}
4
5 This document covers some basic conventions that are used in XWiki codebase. Please read over this document and make sure your code conforms to the rules here.
6
7 = HTML =
8
9 The following rules must be followed:
10
11 * The HTML output produced by XWiki pages must be valid HTML 5.
12 * Use kebab-case for values of the {{code language="html"}}class{{/code}} and {{code language="html"}}id{{/code}} attributes
13
14 == WCAG ==
15
16 The XWiki project is following the [[W3C WCAG 2.1 Guidelines>>https://www.w3.org/TR/WCAG21/]] (level AA). See the [[XWiki accessibility statement>>doc:xwiki:Documentation.UserGuide.Features.Accessibility.WebHome]] for more information about this.
17
18 The following WCAG-related rules (not verified automatically) **must** be followed (in addition to the ones automatically enforced by the [[XWiki's WCAG Tests>>Community.Testing.WCAGTesting]]):
19
20 * Only use icons along text alternatives. The text alternative can be visually hidden.
21 * The size of the target for pointer inputs must be at least 24 by 24 CSS pixels, in LESS use {{code language="css"}}@target-size-minimum{{/code}} [[see exceptions>>Target size exceptions]].
22
23 The following WCAG-related rules **should** be followed:
24
25 * The size of the target for pointer inputs should be at least 44 by 44 CSS pixels, in LESS use {{code language="css"}}@target-size-recommended{{/code}} [[see exceptions>>Target size exceptions]].
26 * [[Properly hide elements>>Properly hiding elements]]
27
28 = CSS =
29
30 The following rules must be followed:
31
32 * the CSS must be valid conform [[CSS 2.1 specification>>http://www.w3.org/TR/CSS21/]]. This can be tested using the [[W3C CSS Validator>>http://jigsaw.w3.org/css-validator/]]
33 * don't use ##!important## declarations.
34 ** An exception to this rule is allowed for a generic CSS class whose purpose is to force some styling (which cannot be forced otherwise).
35 * don't use inline style declarations
36 * (((
37 Some properties must not be hardcoded. Instead they must use Flamingo ColorTheme variables ([[LESS variables>>doc:xwiki:Documentation.DevGuide.FrontendResources.Style variables.WebHome||anchor="HLESSvariables"]] or [[CSS properties>>doc:xwiki:Documentation.DevGuide.FrontendResources.Style variables.WebHome||anchor="HUsingCSSproperties"]]). Those properties are:
38
39 * Colors
40 * Font weights
41 )))
42 * All colors must be defined for either a foregound or a background. To name those, use the “color” word in the variable name for foreground color, and the “background” or “bg” words in the variable name for background colors. For example, we use {{code language="css"}}@btn-default-color{{/code}} for the text color in the default button, and {{code language="css"}}@btn-default-bg{{/code}} for its background color.
43 * test your code all the [[supported browsers>>doc:Community.SupportStrategy.BrowserSupportStrategy]]
44 * the unit must be omitted when the value is zero (i.e., ##width: 0;## is ok, and ##width: 0em;## is not) 1) the unit is optional in this case 2) it is more concise
45 * Use kebab-case for CSS properties (and LESS variables) names.
46
47 The following recommendations could be followed:
48
49 * Properties:
50 ** alphabetical order
51 ** 2 spaces indentation
52 ** put a space between selector and declaration start, ex. "##a {}##"
53 ** put a space before the property value, ex. "background-color: @dropdown-bg;"
54 ** use CSS shorthands
55 ** use relative sizes (em, %) instead of fixed ones (px)
56 ** IE hacks must be removed when updating existing code (since we do not support it anymore)
57 ** Avoid using {{code language="css"}}display: contents{{/code}}.
58 * Organization:
59 ** comment headers for separation and grouping of different parts of the code
60 ** Separate adjacent rulesets with an empty line.
61 * Overwriting:
62 ** document the localization of the overwrite using "Overwrites" and "Should be in" comments
63
64 == Comments ==
65
66 **Short comments** (less then 120 characters):
67
68 {{code language="css"}}
69 /* This is a short comment. */
70 {{/code}}
71
72 **Long comments**:
73
74 {{code language="css"}}
75 /* This is a very long comment that wraps
76 on multiple lines ...
77 and so on. */
78 {{/code}}
79
80 **Sectionning**:
81
82 This style should be used to declare sub-sections on a CSS file.
83
84 {{code language="css"}}
85 /**
86 * Section title.
87 */
88 {{/code}}
89
90 == Tools ==
91
92 * [[Firebug>>http://getfirebug.com/]]
93 * [[CSS Optimizer>>http://www.cssoptimiser.com/]] and [[CSS Compressor>>http://www.csscompressor.com/]] are two excellent online tools that can shrink CSS
94
95 = Testing =
96
97 See the [[Community.Testing]].

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