Simple UI mode
One toggle strips the editor to the essentials, hiding the extra toolbar groups, tool-window stripe, breadcrumb, gutter, and minimap for a calm, minimal surface.
One toggle strips the editor to the essentials (hiding the extra toolbar groups, the tool-window stripe, the breadcrumb, the entire gutter (line numbers, fold chevrons, and all markers), and the minimap) and turns off the heavier features (LSP, debugging, Git, multiple cursors) for a calm, minimal surface.
Toggle it from Settings → Application, the toolbar, the palette, or the --simple CLI flag (session-only). Toggling off restores everything exactly.