Okay... So this isn't really related to Roleplaying Games beyond the fact that I use KDE for my desktop environment on Ubuntu, and Libreoffice to do a lot of my stuff for my personal games and some of my NSN Gaming work. That said
I like KDE, I like LibreOffice. LibreOffice has a few oddities on KDE. The default icon set and drop menus have some issues with dark themes. Also the default icon's aren't all that great. Worse, on a really dark color scheme in KDE, all of LibreOffice's tool tips are black text on really dark background.
So here's what I've figured out.
First, the instructions here are for debian/ubuntu packages... if you run some other version of linux you'll have to adapt.
There's an unoffical set of icons for LibreOffice that are named after the "Faenza" Theme of icons. They look pretty good, regardless of theme color. Get them off of gnomelook's website. Follow the instructions posted.
Yes, those instructions are messy... you download a iconset, then you install an official iconset and replace parts of it with the ones you downloaded... but it works.
Now make some color changes in Libreoffice Tools->Options->Appearance
Set your document background to white, and your font color to black. Why? That's the automatic settings!
Not really... the auto settings pull from your KDE color scheme. And sometimes its weird what you get.
Now pick your dark kde color scheme. If you loose the ability to read your menus and tooltips, change back long enough to enter Tools->Options->View. This is where you set the icons, set them back to oxygen. Change to your dark theme in KDE without closing the LibreOffice Options window, then change back to the "crystal" set (really Faenza). That's when my tooltips and dropbars and menus started being legible again!
Hope it works... tell me if it doesn't and what you had to do to make it work later!