in which line of code can I change the color of it? want to put red instead of gray
The arrows for the SnowFlat theme are done using images. Not sure if your theme is specifically SnowFlat or a derivitive version, but you should find the image at images/vote-buttons-2.png within your theme folder (here is the one for this site).
Use a graphics editor to change the grey ones to red.
Let me know if it helps.
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