I’m going to add an answer to “How to change font styles/sizes in Obsidian?” for referencing in other threads. The contents of this snippet are from the Minimal Theme by @kepano , and can be found here.
/*----------------------------------------------------------------
Font styles
Preview mode and UI */
--text:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Oxygen-Sans,Ubuntu,Cantarell,"Helvetica Neue",sans-serif;
/* Editor mode */
--text-editor:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Oxygen-Sans,Ubuntu,Cantarell,"Helvetica Neue",sans-serif;
/* Code */
--font-monospace:Menlo,SFMono-Regular,Consolas,"Roboto Mono",monospace;
/* Sizes, weights, padding */
--font-normal:16px;
--font-small:13px;
--font-smaller:11px;
--font-smallest:10px;
--normal-weight:400; /* Switch to 300 if you want thinner default text */
--bold-weight:600; /* Switch to 700 if you want thicker bold text */
--line-width:40rem; /* Maximum characters per line */
--line-height:1.5;
--max-width:87%; /* Amount of padding around the text, use 90% for narrower padding */
--nested-padding:3.5%; /* Amount of padding for quotes and transclusions */
--icon-muted:0.4;
--border-width:1px;
--border-width-alt:1px;
/*----------------------------------------------------------------