Class Basics

Named Cascading Style Sheets are divided into:

  • Namespaces
  • Structural Classes
  • Component Classes
  • Type Classes
  • Modifier Classes
  • Functional Classes
  • Exceptions
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Pick a namespace once you provide your library to a third party or need to prevent naming conflicts inside your project.




Prefix Tag Example
{namespace}- * .foo-main
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Structural Classes

Structural classes provide a semantic context for the underlying elements and are preferably utilized to define a layout.




Tag Example
article .content
body .body
footer .footer
header .header
main .main
nav .navigation
section .section
aside .sidebar
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Component Classes

Component classes provide a group context for the underlying elements and are preferably utilized to define a working unit.




Prefix Tag Example
component- * .component-accordion
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Type Classes

Type classes are the foundation for reusable, modular and semantic CSS to provide the reader what elements, tags and sections are affected.




Prefix Tag Example
address- address .address-content
audio- audio, object .audio-content
box- div .box-content
break- hr .break-content
button- a, button .button-content
caption- caption .caption-content
code- code, pre .code-content
col- td, th .col-content
data- datalist .data-content
field- input, select, textarea .field-content
form- form .form-content
frame- iframe .frame-content
image- canvas, img, object, picture, svg .image-content
item- dd, dt, li .item-content
label- label .label-content
legend- legend .legend-content
link- a .link-content
list- dl, ol, ul .list-content
modal- div .modal-content
overlay- div .overlay-content
progress- progress .progress-content
quote- blockquote, citie .quote-content
set- fieldset .set-content
shape- cicle, path, rect, symbol, use .shape-content
table- table .table-content
row- tr .row-content
text- em, small, span, strong, p .text-content
title- h1, h2, h3, h4, h5, h6 .title-content
video- object, video .video-content
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Modifier Classes

There is no limitation to extend your type classes with individual state, size and position modifier. Proper handling of context and type should prevent the need of adjoining classes.


State related syntax:


Size related syntax:


Position related syntax:



Suffix Tag Example
-active * .item-active
-idle * .item-idle
-hover * .item-hover
-touch * .item-touch
-small * .item-small
-medium * .item-medium
-large * .item-large
-first * .item-first
-second * .item-second
-third * .item-third
-last * .item-last
-odd * .item-odd
-even * .item-even
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Functional Classes

Functional classes using pure CSS are marked with the is, no, has and fn prefix. JavaScript enhanced and therefore reusable classes on the other hand can be identified by the js prefix. Each of them should never have styles for painting.


Pure CSS related syntax:


JavaScript related syntax:



Prefix Tag Example
is- * .is-active
has- * .has-tooltip
no- * .no-webgl
fn- * .fn-clearfix
js- * .js-click
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There are exceptions that are not following the specifications.




Prefix Tag Example
wrapper- * .wrapper-body
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