Since Custom CSS is now compatible to Nextcloud 32 as well, you can just apply my CSS rules, if you want to.
Also see the post on my website.
Some of the rules may not be neccessary any longer, but everything works as expected for me so far.
Edit: from time to time I will add additional rules or updates there.
It seems, the coordination between the different āFeatured Appsā in Nextcloud is still not that easy.
When Nextcloud released version 32.0.0 there was also a new version of the text editor component which now provides ādrag handlesā on the left to move text blocks in editing mode and hash symbols when hovering headings, so you can link to headings directly.
However, it looks like Collectives did not know about this at all. First the text editor in Collectives was too small, because of the layout changes introduced in the new version of Nextcloud and the editor:
This got fixed, but then a new issue showed up - now the margins are ok, but the ādrag handlesā and the link symbols for headers are not visible, because another change has to be implemented as well:
As usual I created a workaround for my own instance using custom CSS rules (which I also addded as comment in the Github issue). But I wonder how this happend in the first place. Yes I am aware that there may be changes which need to be backported and may fix this as well. But until this is done, the current user experience is, that Collectives behaves a bit āstrangeā.
And then in āDeckā there is an issue the settings button on the lower left corner, which does not follow the UI of Nextcloud but looks a bit weird:
Again I created a workaround using custom CSS rules. Yes, visual glitches like these this are not a big problem - but I wonder why apps have these issue at all. It would be nice, if there was a common component library to provide stuff like this, so not every single app as to re-invent the wheel and possibly introduce errors or glitches in the UI.
Quick answer: There is and it is used. Otherwise, you would see much more diverse styles.
The point is that the components are rather generic and allow for customization. These take time and need handling.
So, if you want to have a more coupled look and feel, I fear, the FOSS world is not yours. There are spare-time contributors and changes might take time. There is no unique style police in place that will reject an app that looks out of place. And in face, we all make mistakes. it is nice if these can be fixed quickly. But letās be honest, we all have our priorities.
I will quit this discussion here as I personally think it unfitting and personally offending to claim the devs are doing this intentionally. I am dev as well and I am having my own issues. This is not how I want to spend my time. Open issues or continue your rant as you see fit. I am out.
I am sorry - it was not my intention to suggest, that developers are doing this intentionally. My feedback was to reflect how the impression to end users can be.
I am also a developer of open source software, maintain a number of projects on my own and contributed time and money to many projects in the past. I also know what it means to spend free time on projects besides my full time job.
I am using and promoting Nextcloud now for many years, maintain multiple instances used by more than 100 people in total as I believe the best way to convince people to not only use Big Tech products is to provide them alternatives which work for them.
My feedback is an attempt to point out aspects may need a bit more attention if one does not want to give the impression that Nextcloud is just a hobby project that is not suitable for serious use. Nextcloud is not only FOSS - with Nextcloud GmbH there is also a company behind it with a revenue of 2.5 Mio EUR in 2023 according to the information which is publicly available. Maybe it may help to use some of that money to pay developers to get a more consistent UI and to avoid issues like that with Collectives after the upgrade to Nextcloud 32.0.0.
Of course Iād like to participate in the development wherever possible, but my time is also limited and I already maintain a number of projects. But at least I try to help by providing workarounds to fix some of the UI issues.
If thatās correct, a revenue of EUR 2.5 million isnāt really all that much. I mean, come on! The design team at Google who draw the mock-ups for the next iteration of Material Design buttons for the next Android version alone probably costs more than that. 
Obviously, I have no insight into the internal workings of either Nextcloud GmbH or Google. But honestly, EUR 2.5 million doesnāt seem like that much when you consider everything Nextcloud offers.
Yes, I know there are people who say the team should focus on polishing existing core features instead of constantly adding new ones. But if they did only that, Nextcloud would proobably be less competitive with M365 or Google Workspace. People want these features. And in the end, Iād rather have an icon thatās slightly misaligned than see Nextcloud disappear because it couldnāt attract enough paying customers due to missing functionality.
Thank you, this is very helpful!
I second all your proposals to optimize the GUI and after implementing your CSS rules, I spontaneusly said to myself: Yes, this is it!
At least for meā¦ 
To avoid any misunderstanding: Iāve been using Nextcloud myself for many years and maintain multiple instances (the largest one for more than 80 users) for free. Nextcloud Office and Talk are also really great and AIO the AppAPI are a major improvement compared to the humble beginnings!
But besides all the great features itās sometimes little things, which may leave a good impression if they work fine - or not, if there are usability issues or errors. And some issues are already more than one year(!) old like [Bug]: Files: Context menu for files appearing in wrong location Ā· Issue #47970 Ā· nextcloud/server Ā· GitHub .
As silly as it may sound - but sometimes the impression of the UI is as important as the list of features a product has, especially when you want to convince people to switch from Google Workspace or M365 to Nextcloud.
And to be honest: eventhough Nextcloud is already very mature - there is still a significant gap to software like Confluence, Jira, Trello or MS-Teams with the integration of all the other apps Microsoft provides (Iāve been using all this stuff on a daily basis in my regular job for years now).
Of course - Google, Microsoft and Atlassian have way more resources, money and developers to add whatever they want. I even donāt want an exact ācloneā of M365 in Nextcloud and like it as it is. But because of that it would be nice to have the features which Nextcloud has, as good as possible and without the risk of breaking things with every major update.
I only want to help to improve Nextcloud. Unfortunately, I donāt have that much time to contribute a lot of code, but if there is any place to get into touch with the developers to learn how to help getting a bit more consistent UI accross the Nextcloud āeco systemā, Iām happy to do so.
Yeah, I guess thatās fair, and donāt get me wrong, I also appreciate a clean and consistent UI. But after using Linux and open-source software for more than 20 years and running Linux exclusively on my machines for about a decade, I suppose Iāve become quite battle-tested when it comes to. letās say, āunusualā UX and UI design.
In my humble opinion, Google is still unmatched in this regard, and Iād probably use Google Workspace if it werenāt for its well-known disadvantages. Despite the glitches you mentioned, Iād still say Nextcloud is a solid second, especially considering itās a small company compared to Google. Itās certainly far better than Microsoft, which, for some reason, is still used in most companies. 
I created a āHow toā post which explains how to use CustomCSS and also links to my set of CSS rules which I use for my production Nextcloud instance. When itās approved, others may hopefully find my rule suggestions more easily:
If i had someone like @awelzel in an opensource project, who obv. not only really cares about UX, does analysis and comes up not only with specific ideas but solutions, iād probably ask him if he would like to join and contribute to the UI team as āthe guy with the outside perspectiveā.
If there is something I learned about design systems and UX: You need it to manage costs and dependecies and usability, ā¦ but at the same time, these teams tend to get lost in their own little world of system, rules, governance, ā¦ they just loose the most important āthingā out of their sight: The user. Sometimes I got the impression when talking to professional UX teams, they got caught by surprise when i tell them, the interface does not need to work for them, it needs to work for the usersā¦. some UX teams seem to think the design system is the product they build, not the UI.
Iām not saying this is the case in NC. Just want to point out that sometimes, the best you can add to a UX team is an outside view.
Once a version is released, the design is still polished, bugs are fixed but the main decisions are already taken. For the main changes, it is much better to check out the new versions before they are released, so the beta and release candidate versions, which would be for NC 33 from early January next year (Maintenance and Release Schedule Ā· nextcloud/server Wiki Ā· GitHub).
I donāt know when and how the design decisions are taken, if you point out issues in a beta release, there is much more time to do something about it. At this point, constructive feedback from the community is very valuable.
Developers are more active on github, so the specific critique is best placed there, especially and even more on beta and RC candidates. If you want to post an overview here and link the issues or something, that is perfectly fine.
Just for completeness: for nearly all issues I addressed with my Custom CSS rules, I also created GitHub issues (along with the information which workaround I created to fix visual problems).