It has begun.After couple months of work, I have now finally managed to cobbletogether the QtWidgets side of Union.This means that your QtWidgets apps, such as Dolphin, KMail, Kate etc. cannow use the Union CSS files as the source of their styling.However, temper your expectations, as this is the first initial release! Do note that there are visual bugs and oddities!I'm still working on things!So yes, as you can see, some things look off. Not Breeze at all!Some things are just different, some other things have wrong colors.These are all fixable and I will do my best to get as many things as possiblefixed for the Plasma 6.8 release.But some other oddities are kind of expected: This is the first time everBreeze QtWidgets and QtQuick style have same shared source-of-truthas an easily editable file! (Excluding colorschemes.)So some of these designs are made with QtQuick in mind, so they can look a bit off in QtWidgets.I'll go through here what I did and what still needs to be done,but this was a huge undertaking, so I'm having a small celebration for the very first release of this. :)Hold on, can I try it!?Yes! It should be released in Plasma 6.8, unless someone tells me no.As of writing this, nobody has said no.You can make your own CSS files and see them affect QtWidgets apps too.Just expect some breakage and report all the bugs!Go crazy with the themes. Try everything. Bring back whimsy to computers.Tell us about the theming experience in general.Have fun. Your computer should be just as cool as you are.The rest of this blogpost is more a technical rant and ramble as I amventing all the exhaustion over this thing, lol.QStyle is difficultQStyle themes, which are the styles that modify the look of QtWidgetsapplications, are not easy to work on. Most themes I've seen takean existing one, such as Fusion or Breeze and make their changes on topof those.But for Union, we had to start from scratch. I took the very basic base of QStyle,which is called QCommonStyle (kind of a fallback theme), and began building on top of that.Then, there was multiple parts:Figure out a way for the QStyle to paint things using CSSBuild a hierarchy of the style by reading the CSS data and applying it to QStyle worldCreate a completely new set of element files we useThe QStyle themes are very unwieldy and hard to work on otherwiseGo through every single element and ensure they read all data from the CSS correctlyAnd ensure the style stays backwards compatible!This is still ongoing process, most bugs lurk here. :PFigure out how to use Union layouting system within QStyle elementsThis is also buggy, as QStyle is more "rigid" with layoutingApplications expect very specific layouting from QStyles over the years it has existedSo any application that deviates from those expectations will look brokenCaching so that the style is performantHere Arjen helped me a lot, thank you!And a lot of other stuff I have already forgotten..Thankfully redstrate had already made the painting part for the verysimplified proxystyle (which took Breeze and modified it a bit), so I did not have to modifythat too much. I mostly had to poke at it to make it work with my hierarchy system.So thanks!