Font Management

Molkit lets you set the typeface for atom labels and text annotations, and add fonts beyond the five built-in system faces. Fonts you choose are tracked with the document so they survive save and reload, and they carry into SVG and other exports. This page covers where you pick a font, how to add Google or local fonts, and what happens when a saved file references a font you no longer have.

Where you choose a font

There are two places fonts get applied:

Atom labels. Open Structure Settings and go to the Atoms panel. The Label Font dropdown sets the typeface for element symbols across the structure. The default is Arial; the list also includes Times New Roman, Helvetica, Georgia, and Courier New, plus any fonts you have added.
Text annotations. When you edit a text annotation, the formatting toolbar shows a font picker. Each entry previews in its own typeface so you can see it before applying. Selecting a Google font loads it on demand.

The five system fonts (Arial, Times New Roman, Helvetica, Courier New, Georgia) are always available and need no setup.

Adding fonts

Both the Label Font dropdown (the + button next to it) and the annotation font picker open the Add Fonts dialog. It has two modes:

Google fonts

Search the curated Google Fonts catalog by name or browse by category (sans-serif, serif, display, handwriting, monospace). Typing a name also runs a live check against the Google Fonts API, so fonts outside the bundled list can still be found. When you add a Google font, Molkit injects a stylesheet link to load it; nothing is downloaded to your machine.

Local fonts

Switch to the Upload tab to add a font file from disk. Supported formats are .ttf, .otf, and .woff2. The file is stored in your browser (IndexedDB) and registered with an @font-face rule so it renders immediately. Local fonts are tied to the browser you uploaded them in.

Added fonts persist in your font library across sessions. To remove a user-added font, select it in the Label Font dropdown and click the × button; this also deletes a local font’s stored file.

Missing-font warnings

Molkit records which non-system fonts a document uses and saves that list with the file. When you open a file that references a local font missing from this browser, a status-bar notification appears reading Missing font: "<name>" with two actions:

Upload opens the Add Fonts dialog so you can supply the file again.
Substitute prompts for a replacement name and swaps it across all atoms, annotations, and structure settings. Leaving it blank falls back to Arial.

Google fonts referenced by a file reload automatically, so the warning is specific to local fonts that are not present.

How fonts reach exports

Before each save, Molkit scans the document for every non-system font in use and stores an accurate list. On export, those fonts are written into the output so the file looks right elsewhere: local fonts are always embedded as base64, and Google fonts are either embedded or linked depending on the export option. See the export fonts page for the embed-versus-link choice.