Design principles¶

A tarn is a small, still mountain lake. Tarn takes that stillness as a design aim: give the reader a calm surface for reading, with clear cues for finding their way.

By day, you read against the warm grey of sunlit clouds over the lake. By night, the page becomes the sky above it: a starlit indigo, deep blue-violet and never black. Both palettes draw on the same place at different hours.

Text takes priority in the default appearance. The header shares the page background, and thin dividing lines separate regions without large blocks of contrasting colour. Spacing and heading sizes give the text structure. Borders and icons draw attention to controls or distinguish kinds of content. The aim is to keep these cues useful without making every part of the page equally prominent.

Tarn retains Zensical's interactive controls, which can include transitions and shadows. The surrounding reading surface stays visually quiet so that readers can find the controls when they need them.

Colour has recurring roles within this design. The default blue marks links and primary buttons, as well as the current page in navigation. Green marks learning and success. Inline code uses plum in light mode and muted lavender-silver in dark mode. Its monospaced font and quiet background chip distinguish names from prose and blue links. The colour explanation describes the palette, while Diátaxis in the navigation explains the section cues.

These choices shape Tarn's defaults. A site's own logo, colours and fonts can change its appearance through Zensical configuration and CSS overrides. The guides to adding a logo and adjusting colours describe how to customise them.