UPDATE
Then i decided to make the best that suits me so far, both strips at the end with some gap together with white paper
It turns out like this with single strip...

And with the double strips
even though the glowing effect is not equally distributed, but it's fine for me since its my first experience doing this...maybe other sifu can give better suggestions on dealing with RGB colors...
First attempt (without gap, LED strip attached closely to the edge of the acrylic);

Second attempt (with gap, LED strip at attached directly to the acrylic...just below the surface with gap around 0.9 cm, black tape attached to cover the LED bulb);

It turns out a lil bit better...perhaps dealing with multi-color LED is not that easy..but this is the best so far...
Experimentation still under progress, perhaps a lil bit slow due to packed schedule..got a 2-months contract work to earn some money before starting off my third year later..