Both. Tabs for indents. Spaces for alignments after the indent level is reached. Everyone can view code with their preferred indent width. Perfect solution wi

Both. Tabs for indents. Spaces for alignments after the indent level is reached. Everyone can view code with their preferred indent width. Perfect solution with no flaws or drawbacks. Maybe 1 drawback, it requires advanced tooling (emacs smart-tabs-mode) to automatically handle the indentation/alignment. Indent width is a visual effect. Mandating an indent width with hard spaces is like mandating the color scheme.