The common frame
The header, the tab bar and the team switcher, present everywhere.
Every page except sign-in and the error pages shares the same frame. Learning it once is enough to find your way anywhere.
At the top: where I am and who I am

The pill on the left carries the name of the active team, tinted with its colour. That colour is derived from the team identifier: it cannot be set, but it never changes either, which makes it a reliable landmark when you juggle two teams. The user name on the right is a reminder of which account is writing, a detail that matters on a phone left on the kitchen table and picked up by anyone.
The intent is simple: no entry should ever land in the wrong team by inattention. So the answer is shown permanently, not hidden in a menu.
Switching teams
Touching the pill opens a sheet that slides up from the bottom and lists the teams I belong to.
The active team is not stored in the database, it is a setting of the device. The phone can stay on the household while the laptop stays on the association, without the two stepping on each other.
At the bottom: four tabs

The bar stays pinned at the bottom, within thumb reach. Four tabs only, ordered by how often they are used: you add time often, you look at statistics regularly, you deal with tasks now and then, you visit the settings rarely.
Two important screens deliberately have no tab. “My time” is reached from the statistics and from the settings, because you go there to correct something, not to browse. “Categories” is reached from the Add tab, exactly where a missing category makes itself felt.