The font size in the Composer and chat window is too small. I don’t want to use Command + because it enlarges all windows along with it, which is not an ideal solution. I just want to increase the font size, but I couldn’t find any settings for this.
In my searches, I came across suggestions about installing some extensions and adding specific code to the settings.json file. I tried it, but it didn’t have any effect.
If anyone could help, I’d greatly appreciate it. Thanks! 
Hey, install this extension and add the code, then change the font size to the desired value.
"custom-ui-style.stylesheet": {
".anysphere-markdown-container-root": "font-size: 14px !important; line-height: 1.5 !important;"
}
“Oh, thanks a lot! That worked perfectly, and now the size is bigger. :))
I was just looking for this struggling with my presbiopya, and after installing the extension and adding lines to settings.json ( I guessed ) with this exact contents :
"custom-ui-style.external.imports": [
".anysphere-markdown-container-root": "font-size: 14px !important; line-height: 1.5 !important;"
]
I got the warning to reload the windows by Custom UI Style
and immediately a much severe message :
“Your Cursor installations appears to be corrupt. Please Reinstall.”
Then I removed both settings and plugin and prayed 
for a few seconds, luckly it worked !
Then I went to the 2nd post found ( mentioning this one ) and found the best way to do it :
Ctrl+CMD +
GENIOUS @hiteck !!! thanks a lot
and @deanrie always helps and give the best advice, constantly this was a first time and unique event, you still rank #1 community hero for me ( and I assume many of us here ).
Why Apc Customize UI++ doesn’t work anymore after 0.45? It applied changes seamlessly.
Custom UI Style requires restarting Cursor every time when i make changes.
and does Anysphere have any plans to provide actual solution to this? other than making people relying on third party extensions and looking for alternative solution every time when there is an update?
I answered this question here:
As for solving the problem, I think we have it in our plans, but I can’t say anything for now.
hi,
using 0.47.8 and this method does not worked for me. installed and enabled the extension, added the code in settings.json…
its quiet annoying to face such a problem btw. we should just simply and easily adjust the font configuration.
0.47.8, custom ui style works for me.
"custom-ui-style.stylesheet": {
".anysphere-markdown-container-root": "font-size: 16px !important; line-height: 1.5 !important;",
".markdown-section": "font-size: 16px !important; line-height: 1.5 !important;",
".monaco-mouse-cursor-text": "font-size: 16px !important; line-height: 1.5 !important;",
".aislash-editor-input-readonly": "font-size: 16px !important; line-height: 1.5 !important;",
},
"custom-ui-style.webview.enable": false,
Such font size make my eyes feel better. The last line must be added, or you see nothing in webview frame. Check the markdown file preview, you’ll got what I mean.
BTW, you should choose “open chat as editor”, and drag the tab to join other file editor tabs.
we Got the What & we Got the Why but anyone else but me wondering about the Where ? this be great, specificaly Where would be greatly apreciated.
Not working on Cursor 0.48.7
It looks like on the main page of the extension the author states that it has not been tested with Cursor - FYI. That link to alternative extensions goes nowhere.
Installing this extension did not change the font size, but it broke something in the editor - now my cursor is not where it actually is (that is when I position the cursor and start making changes they turn out to be couple of characters to the left). What is worse is that uninstalling the extension and removing its variables from settings did not solve this problem. So thanks to this I will now have to do clean re-install of cursor on my laptop! How great!
All because there is no easy official way to change font size in the AI panel from unreadable.
Worked for me using custom ui style but only after I removed the space before “!important”
"custom-ui-style.stylesheet": {
".anysphere-markdown-container-root": "font-size: 16px!important; line-height: 1.5!important;",
}
p.s. for anyone trying to change prompt input font size in chat add this:
".aislash-editor-input": "font-size: 16px!important; line-height: 1.5!important;",
This works for changing the font of both the prompt inputs into Cursor, and for changing the way the prompts are then displayed in the conversation by accessing the readonly version of the class as well (bottom two lines) 
"custom-ui-style.stylesheet": {
".anysphere-markdown-container-root": "font-size: 13px !important; line-height: 1.4 !important; font-family: Consolas, monospace !important;",
".chat-input": "font-family: Consolas, monospace !important; font-size: 16px !important;",
".aislash-editor-input": "font-family: Consolas, monospace !important; font-size: 12px !important; line-height: 1.5 !important;",
".aislash-editor-input-readonly": "font-family: Consolas, monospace !important; font-size: 12px !important; line-height: 1.5 !important;"
},
I found a dumb workaround: click the 3 dots in the chat window and click “Open as Editor”. Then right click on the “Chat” tab and click “Move into New Window”. In the new window, using cmd+= to zoom in is not gonna affect the other editor windows. And arrange the windows as you like. The layout seems to persist between sessions.