Chuunibyou demo Koi ga Shitai! was a 12 episode anime TV series aired in 2012. Main character Rikka owns an extravagantly decorated Mauser Schnellfeuer model 712 (here in the hands of Yuuta):
This from the ending credits is probably the most detailed shot:
It seems though she also has a plain regular C96 model:
So because fandom I attempted to recreate the decoration:
Nailed it:
DAMN, Nice DIY there