A more flexible chart element function that modifies built-in chart element functions to add thick lines:

    ClearAll[ceF]
    ceF[cedf_: "GlassRectangle", o : OptionsPattern[]][col_: Black, thickness_: 3] := 
      {ChartElementDataFunction[cedf, o][##], 
       col, AbsoluteThickness[thickness], 
       Line[{{#[[1, 1]], #[[2, 1]]}, {#[[1, 1]], #[[2, 2]]},
             {#[[1, 2]], #[[2, 2]]}, {#[[1, 2]], #[[2, 1]]}}]} &

Examples:

    SeedRandom[42];
    data = RandomVariate[NormalDistribution[0, 1], 200];

    Histogram[data, ChartStyle -> 1, ChartElementFunction -> ceF[][]]
![Mathematica graphics](https://i.sstatic.net/SgudS.png)

    Histogram[data, ChartStyle -> 1, 
     ChartElementFunction -> 
      ceF["FadingRectangle"][Dynamic[Darker@Darker@CurrentValue["Color"]], 5]]
![Mathematica graphics](https://i.sstatic.net/VwoMx.png)

    Histogram[data, ChartStyle -> 1, 
     ChartElementFunction -> 
      ceF["FadingRectangle", "GradientOrigin"->Top][Dynamic[Darker@CurrentValue["Color"]], 5]]
![Mathematica graphics](https://i.sstatic.net/99s98.png)