Deepin GTK theme for GNOME fell in love with Arc theme and they had a baby. For the most part it's Deepin theme look, but with Arc accent colours, window buttons, and wiget styles for radio buttons, switches and many other.
This theme is mostly a mash up of those two themes, credits go to the authors or Deepin and Arc GTK themes.
You end up with beautiful flat GTK theme with transparent elements for GTK 3, GTK 2 and GNOME Shell, high contrast, beautiful whites and blacks and with Arc's blue accent.
Clone the repository into ~/.themes or as root into /usr/share/themes for global installation, you can also download it as ZIP file. On GNOME you also want to install Gnome Tweak Tool and User Themes plugin. Then use Tweaks Tool to change GTK and Shell theme to DeepinMeetsArc.
In future I'll look into getting it on Gnome Look website and packaging.
To uninstall just remove DeepinMeetsArc directory from place of installation.
If you find a bug please report it here. Note that I only tested it under Gnome 3.24 but theme should also work under 3.26.
Both Arc theme and Deepin theme are aviable under GPL-3.0, and so is DeepinMeetsArc. See LICENSE file for full license text.