You can see their names and change them in "Plugins/Plugin Options" and then "Isabelle/Rendering". The names give a relatively clear explanation, and you can refer to the manuals from the terms used in the names.
There is a lot of colors so I won't describe them all.
For the most important default colors:
Logic:
- blue : free variable
- green : bound variable
- orange : skolem constant ("free" variables existentially "quantified")
- cyan : syntax (not a variable or a constant, like
case
or if
)
Isar Keywords:
- sky blue : commands (like
lemma
, proof
or have
)
- red : tactic-style commands (like
apply
, done
or prefer
)
- turquoise : statements (like
where
, fixes
, shows
or and
)
Messages highlighting in output:
- red : error
- yellow : warning
- light blue : info
Highlighting in editor:
- red : error
- light yellow : current line
- gray : quoted text (logic and types)
- light gray : comment and formal text (introduced with
text
or section
)
- purple : running process on the command (also shown on the right)
- pink : unprocessed (outdated) command (also shown on the right)
In general, an underlined command displays a message in the output (possibly associated with an icon and a box on the right). More specifically:
Icons, [boxes] and {in text}:
- red exclamation mark [red box] {squiggly red underline} : error
- orange exclamation mark [orange box] {squiggly orange underline} : warning
- blue i {squiggly blue underline}: information (often provided by automatic tools)
- {squiggly gray underline} : the command shows a message in the output
- {red text} : comment (like
(* This is a comment *)
)