Hi, A suggestion: I think it would be nice if you moved the "Custom Styles" CSS edit field to the top of the page it's on, and added a save button next to it. Alternatively, would be to create a page just for the "Custom Styles" editing.
The rationale is that on this page most of the fields are links to files which would be set once and then never touched, whereas the manual edits are done rapidly while trying out different things. Each time I have to scroll all the way down to the field, make a small change, then scroll to the bottom to click save. That then refreshes the page and I have to repeat this whole process.
There is a general reorganization of the options pages underway, the effects of which can be seen on various admin pages in the recent releases.
Technically the only situation in which you will revisit the custom CSS is during your blog's initial setup, so once you have finalized it, it will be as invariable as the rest of your fields on that page. But I agree that it can be a bit of a headache if you are making repeated changes to it.
That being said, adding a "save" button next to individual fields is a major pain to implement, since it will require a fundamental redesign of the options pages.
I do admit this simple & repetitive task will be time-consuming - but calling it a "headache" is too much!
My first reaction when I saw this was a series of expletives in each of the 7 languages that I speak. But in keeping with my self-created forum rules I decided not to post those.
I know what I have coded in Suffusion - not you. I know what is a real pain to implement - not you. I am calling this a headache, since this is a monster-bore and I will be doing the work just because somebody like you is too lazy to scroll down a page about 10 times a year. Instead of asking me to do this for you, you could be a lot smarter about it and simply create a CSS file with your custom styles and save it ONCE by including the CSS file in the Custom Includes page, rather than repeatedly saving information on the same page.