Typography¶

Note: The Siemens font is part of the official Siemens branding and must not be used in non-Siemens applications. Element uses a default font that is not associated with Siemens branding. Please note that the default theme is currently undocumented.

Typographic hierarchy is defined by text size and color. Each style can use color variants if necessary.

Usage ---¶

For a cohesive typography experience, Element's type scale uses the Siemens Sans typeface. Hierarchy is communicated through differences in font weight (Roman and Bold) and size.

Best practices¶

• Respect the typographic scale order for consistent and hierarchical design.
• Consider the purpose and context of the text when selecting a type style. Headings, subheadings, and body text each serve distinct functions and should be chosen accordingly.
• Combine font weight, size, and color to establish hierarchy, utilizing lighter colors or smaller font sizes to de-emphasize secondary content.
• Avoid style changes like bold and italic in the middle of a paragraph.

Design ---¶

Element’s typography is divided into body, headings and display styles.

Body¶

Body text is used for the main content, often following a heading or as part of UI components.

• Use body as the default style for most components and text blocks.
• Use body-lg for larger and more prominent text.
• Use caption for small, supportive text like annotations or metadata.

All body styles are also available in bold and italic. Bold is used to add emphasis or draw attention to key information, and is also applied in specific UI elements, such as button labels, or highlighted values in tables and lists.

Italic is used sparingly, for cases like technical terms.

Headings¶

Headings communicate the structure and visual hierarchy of content on the page. They are defined semantically from h1 to h6.

• Use h1 as the visual style for the largest headings.
• Use h2 as main page headings.
• Use h3 as section headings.
• Use h4 as secondary section titles.
• h5/h6 share the same visual style, used for smaller content blocks like cards or tertiary titles.

In order to adhere to accessibility best practices, each page should be structured according to the semantic hierarchy h1, h2, ... h6, starting from h1 and maintaining a logical order without skipping levels.

Web browsers, plug-ins, and assistive technologies rely on this structure to provide in-page navigation. When visual requirements do not align with the semantic hierarchy, the appropriate HTML elements (h1, h2, ... h6) should still be used, with the desired visual style applied through CSS classes.

When the visual style of h1 is too prominent for typical in-page headings, such as the page header, the h2 style is used instead for visual balance.

In this pattern, the h1 tag is assigned to the application name in the application header. This preserves both visual hierarchy and correct semantic structure for assistive technologies.

Links¶

• WCAG SC 2.4.10
• WCAG technique G141
• WCAG technique G69
• WCAG tutorial page structure

Display¶

Display styles are used for high-impact content, such as hero sections, widgets, or dashboards. They should be used sparingly to maintain clarity.

Using the bounding box¶

The vertical height of the text, known as the bounding box, is determined by the line-height. The value of the line-height is critical to make sure text aligns to the 8px grid.

Use the height of the bounding box together with top and bottom margin to determine spacing.

Line length¶

Wide lines of text are harder to read; aim for 45-75 characters per line on desktop, and 30-45 on mobile for optimal readability.

Color usage¶

Color is used in text to communicate information to the user. Color variants have meaning and are used to call attention to an action. The color of text must follow one of the predefined color variants and must not use any of the other defined colors.

See the Text Colors chapter.

Code ---¶

Type styles classes¶

Implementation of typography is done via Bootstrap's typography system. Mosts scenarios allow you to use the HTML semantic (e.g. h1, p) directly, all the required styles are set by default.

In case you can't use the HTML semantic (e.g. apply a text style to a non associated HTML tag) or you have to use a type style without matching semantic, you can use the .si- text classes.

Display styles classes¶

The display styles are provided as si-display* and are mapped to the related Bootstrap classes.

Typography specification¶

All font-sizes, line-heights and font-weights are specified as SASS variables, which can be used if required. The variables come in the form of $si-font-size-[name], $si-line-height-[name], $si-font-weight-[name] and are defined in _typography.scss.

@use '@siemens/element-theme/src/styles/variables';

font-size: variables.$si-font-size-h1;
line-height: variables.$si-line-height-h1;
font-weight: variables.$si-font-weight-h1;

We use the specifications for defining the style CSS classes and for configuring Bootstrap's typography system.

Color variants classes¶

Changing the color of a text can be done using bootstraps utility classes, without the need to of any custom SASS styling and is recommended in most cases. The default text color is applied automatically and only has to be defined, if a higher level component overwrites it.

All color variants can also be applied alternatively using SASS. It is heavily recommended to use the contextual colors for this:

@use '@siemens/element-theme/src/styles/variables';

color: variables.$element-text-primary;
color: variables.$element-text-secondary;
color: variables.$element-text-disabled;
color: variables.$element-text-active;
background-color: variables.$element-base-warning;
background-color: variables.$element-base-danger;
color: variables.$element-status-danger-contrast;
background-color: variables.$element-status-danger;

See _semantic-tokens.

Bootstrap typography utilities¶

Further typographical styling can be done using Bootstrap's wide range of font and text utility classes. They closely follow the HTML semantic and can be used without any additional styling.