Today I successfully changed the font using a custom CSS file. However, I had to resorted to use the “Toggle Developer Tools” to inspect the DOM.
With Obsidian default theme, to change the font:
/* Set fonts for both Edit and Preview mode
.view-content {
font-family: 'Courier New', monospace !important;
}
*/
.markdown-source-view {
font-family: 'JetBrainsMono Nerd Font', Menlo, Monaco, 'Courier New', monospace !important;
}
.markdown-preview-view {
font-family: Lora, sans-serif !important;
}
Please make sure that you activate the snippet under Settings > Appearance > CSS snippets.