How to apply two kinds of Plot styles in single graph

My version is 9.0

I want to apply ColorData and Line Width styles at the same time, like the ColorTheme Function new in 10.0, but there is always errors. Codes under here:

a[x_] := Sin[x] b[x_] := Sin[x - 2 Pi/3] c[x_] := Sin[x - 4 Pi/3] f[x_] := Max[a[x], b[x], c[x]] g[x_] := Min[a[x], b[x], c[x]] Plot[{f[x] - g[x], a[x] - b[x], a[x] - c[x], b[x] - c[x], b[x] - a[x], c[x] - a[x], c[x] - b[x]}, {x, 0, 5 Pi}, PlotStyle -> {Thick, Dashed, Dashed, Dashed, Dashed, Dashed, Dashed}, PlotRange -> {-2, 2}, AxesLabel -> {\[Omega] t, Subscript[u, Subscript[VT, 1]]}, AxesStyle -> {{Arrowheads[{0, 0.025}], Italic, 12, FontFamily -> "Helvetica"}, {Arrowheads[{0, 0.025}], Italic, 12, FontFamily -> "Helvetica"}}] And graph is

How can i make lines separately Dashed and Thick, and at the same time the graph can use ColorData for a different view?

Suspect this is a duplicate. Not sure if it is the most straightforward but, e.g.:

PlotStyle ->
Transpose[{ColorData[3, "ColorList"][[;; 7]], {Thick, Dashed, Dashed,
Dashed, Dashed, Dashed, Dashed}}]


or, in the same vain:

PlotStyle ->