The icons were swapped to lucide line icons, but the buttons kept a boxed/light
background that clashed with the minimal toolbar icons. CSS-only fix: render
.tab-timeline + .push-toggle-btn as transparent, monochrome 18px line-icon
buttons (text-dim, accent on hover/active) — identical to .toolbtn — overriding
the earlier boxed default. Markup unchanged (tests stay green: 158 push+tabs).
b273b61795
