Slate Blackboard Chalk

The classroom slate blackboard — first dark-gray slate, later porcelain-enamel in its signature green — is a matte surface dusted with white chalk and the ghostly streaks of an eraser. Wikipedia documents "Blackboard Green" as #274C43, the deep black-green that carries looping chalk script.

This design system distills that vernacular: a genuinely dark slate ground, hand-written headings in white chalk, pale-green annotation smears, and diagrams drawn as if pulled freehand across the board.

教室里的黑板 —— 最初是深灰色石板，后来是带有标志性绿色的搪瓷板 —— 是一块布满白色粉笔痕迹与黑板擦拖扫的哑光表面。维基百科将这种"黑板绿"记录为 #274C43，这种深黑绿色承载着回环缠绕的粉笔手写体。

本设计系统提炼了这一民间质感：真正深沉的石板底色、白色粉笔书写的标题、淡绿色批注涂抹，以及仿佛在黑板上徒手随意绘出的图表。整体保持哑光石板感，覆着粉笔灰与擦痕，从不光亮，也绝不是奶油色或纯白。