Changed

• Failed unlock attempts now stop at and highlight the directly missing prerequisite instead of silently relying on recursive purchasing.
• Added an on-screen explanation naming the prerequisite, target node, unmet attribute requirement, or missing skill points.
• Refreshed the skill tree presentation with a panning grid backdrop, clearer connection lines, framed nodes, stronger hover and selection feedback, a polished skill point header, and bordered detail overlays.
• Removed the fallback chat message that printed Activated ability: <id> when an ability node had no registered handler.

Fixed

• Prevented empty ability-slot labels from overlapping their slot names.
• Highlighted the first blocked prerequisite node after a failed unlock attempt, or the skill-point counter when the planned unlock path costs more points than are available.