Unfortunately we cannot change the theme of ArchiCAD itself but you can change themes of Windows. I did some experiments and installed this one:
https://www.deviantart.com/yorgash/art/Steam-VS-for-Windows-7-449032822
Its appearance is based on Steam and its code is based on AERO theme which is default for Windows 7. Nice option if you have ArchiCAD 20 or newer, which will not run if you change your Windows theme to classic.
Gotta say, this theme is really dark and you may find some icons hard to see (both in OS and ArchiCAD GUI). But if you know ArchiCAD and your system well enough, this shouldn't be a burden. I personally love this theme - it's elegant, reducing contrast on my screen and strain of my eyes.
If you like dark GUIs, you can give this theme a chance. I checked it on my computer - no viruses.
Just remember to first patch your system settings in order to allow proper installation of external visual styles (themes). All the instructions you'll find in the link.
If you're curious, some other programs will also be affected by changing Windows theme. Here I listed some of mine:
Other programs with GUI that WILL be fully affected by changing (AERO-based) Windows theme:
- Corel Draw
- Trimble SketchUp
- Mozilla Firefox
These will NOT be affected fully (or not at all):
- Autodesk AutoCAD (I guess any Autodesk soft)
- GIMP (unless you change the setting of theme to "system" - GIMP has quite customizable GUI)
- Blender (it's actually dark itself)
- Rhinoceros (part of the GUI is affected and it looks a bit strange but acceptable)
- any Adobe program
- Google Earth Pro
- MS Officle bundle (Word, Excel, PPoint etc.) but default page color will change to dark gray so you'll have to alter this by hand every time (no problem for me).
ArchiCAD 25
Windows 10