in text object, press tab on beginning of each line makes TOO LONG indent.

How many different fonts or font sizes are involved? Maybe it would make sense to create a template file with all the variants and then copy only what you need into the new file?

Please show what exactly we are talking about.

Create two paragraph styles - one for 6pt and one for 12pt and set the tab as desired. That's all.

The question is changed as follow:

Hello,
I usually hand-input many lines of text of lecture notes in AI.

To organize the notes, I need to frequently make 1,2 or 3 indents on different lines to make them organized in a hierarchy manner.

What I do is to locate the cursor to beginning of one line and press tab button for 1,2,or 3 times.

It looks roughly OK, but sometimes I thought that the stroke of tab button makes a huge indent.

The I tested and found that tab indent is independent of font size, so if one-stroke of tab button make a nice indent of one line in 12 pt, it will looks too long in a line of 6 pt.

So is there a option to let the one-stroke of tab button makes a indent of length of several characters unddert current font, instead of fixed length?

Thanks.