With[{styles = {"Section", "Subsection", "Subsubsection"}},
    SetOptions[EvaluationNotebook[],
        DockedCells -> Cell @ BoxData @ ToBoxes @ Button[
            "align",
            Map[
                Set[
                    CurrentValue[#, {CellMargins,1,1}],
                    CurrentValue[PreviousCell[#, CellStyle->styles], {CellMargins,1,1}]
                ]&,
                Cells[CellStyle->"Text"]
            ]
        ]
    ]
]