Based on @PureLine's answer and many other answers to related questions, I test my Mathematica for maybe 4h to learn the following things. And I will give the maybe untimate method to do this (At least works for my Mathematica 13.1).
The problem also arised when I got my new computer with relatively high screen resolution(2.5k). That's the code-assistant-popup fonts is too small, not zoomed to the ratio of the other normal texts. Even, I use other stylesheet instead of Default. So the problem become more complex.
Phenomena I encounter includes:
- Don't know what terms control only the code-assistant popup font.
- When I find out the answer, it's found that it doesn't save the change I make. i.e. I do successfully change the font, but when I close and reopen the .nb, it come back to the original status.
So here is the solutions:
Case A. You use Default stylesheet.
Go to menu Format / Edit Stylesheet. This open the first window which is going to (futher)modify your current stylesheet. It's first line is "Inheriting base definitions from style sheet Default.nb"
Open the Core.nb, find the following terms (depends on your need). Copy them one by one to the first window mentioned before. Append them in the next several lines, as follows:
(I suggest to set them in the same size, a little smaller than the code in the notebook.)
As for the meaning of these 5 terms, just change it to a big font and try typing some code (e.g.
Table) and you will understand. (It's so hard to describe sorry.)
Change them to the font style you wants. For examples, 12 pts heavy.
In the top of the window, click "Export" and name it. Then this is your stylesheet in which fonts are correctly(as you want) shown.
Apply it to your current notebook or set as default.
Case B. You use some other stylesheet.
ATTENTIONS!!! Before going into next steps, DESELECT it from the "DefaultStyleDefinitions"! Otherwise it will fail.
After this prior preparation, open your stylesheet file (e.g. my "Dracula.nb"). Go to the 2. and 3. steps mentioned before. And the 4th step is, save the file. Finally step 5----set it again as the default stylesheet by going to
Ctrl+Shift+O(see Additional knowledge 1.).
- How to set stylesheet .nb file as default. : Press
Ctrl+Shift+O, in "Show option values" select "Global Preferences". Search in "Lookup" for "DefaultStyleDefinitions". Change it to your stylesheet .nb file. Reboot Mathematica.
- There is a bug here. That's why you need to deselect original stylesheet before successfully update it. The phenomena that it goes inaccurately: a.
Ctrl+S doesn't save the file and when you close the window you
receive a warning asking whether to save it. Actually even though
you tap "Save" it doesn't work. b. You reopen the stylesheet file. You will find all your changes have disappeared.