Opera desktop and Nepali Unicode

Nagariknews.com in opera looks very unreadable in nepali unicode font at least difficult. The mangal font would have been easier to read in the browser. Firefox by default takes mangal and so no problem in it. But opera (my version 11.61) takes Aparajita as default in monospace font for Devnagari. In monospace font it is only Aparajita font, could not be changed. Though changing the other in Mangal worked in my co-workers but has not resolved in mine. Whereas Kantipur site is fine in this.

For the co-worker changing it to Mangal font in Normal section  Devnagari Writing system > in International fonts from the fonts of the advanced tab from the preference menu, it switched back to Mangal Font.

Tools >> Preference >> Advanced >> Fonts >> International fonts >> Writing system >> Devnagari >> Normal font >> Mangal.