Clearer controls in chat

Changed

• System messages are no longer uniformly white. Their body uses a calmer cool tone while player chat stays white, making the two kinds of text easier to distinguish.
• Controls such as right-click and Esc now appear as compact keycaps. Supporting instructions are subdued, so the important action stands out immediately in fading chat as well.
• EXP values, repetition counters, and the /pm command now use restrained color accents that improve scanning without turning messages into multicolored blocks.