Thin Table Dividing Row

Question

I need to add some dividing rows to a longtable to set apart different sections. The Word template I'm working off of has dividing lines like so:

My current attempt to replicate this uses three hlines and changes \arrayrulewidth and \arrayrulecolor for the middle one. Some example code:

\documentclass[letterpaper,10pt]{article} 
\usepackage[margin=.5in]{geometry}
\usepackage[table]{xcolor}
\usepackage{longtable}
\usepackage{array}
\usepackage{multicol}
\begin{document}
\arrayrulecolor{red}
\begin{longtable}{|m{1.5in}|m{2.5in}|m{2.5in}|}
\hline
Section 1 & Scales 1 & Subscales 1 \\
\hline
\noalign{\global\arrayrulewidth=4pt}\arrayrulecolor{blue}
\hline
\noalign{\global\arrayrulewidth=.4pt}\arrayrulecolor{red}
\hline
Section 2 & Scales 2 & Subscales 2 \\
\hline
\end{longtable}
\end{document}

However, this causes a break in the outer border and looks a little awkward:

Is there some workaround to get the border to show, or is there an alternate way of achieving this?

Answer 1

This is easy to do with \hhline:

\documentclass[letterpaper,10pt]{article}
\usepackage[margin=.5in]{geometry}
\usepackage[table]{xcolor}
\usepackage{longtable}
\usepackage{array, hhline}
\usepackage{multicol}

\begin{document}

\arrayrulecolor{red}
\setlength{\doublerulesep }{4pt}
\doublerulesepcolor{blue}
\begin{longtable}{|m{1.5in}|m{2.5in}|m{2.5in}|}
\hhline{|-|-|-|}
Section 1 & Scales 1 & Subscales 1 \\
\hhline{|=|=|=|}
Section 2 & Scales 2 & Subscales 2 \\
\hhline{|-|-|-|}
\end{longtable}
\arrayrulecolor{black}
\doublerulesepcolor{white}

\end{document} 

Answer 2

For information, here is what you can do with {NiceTabular} of nicematrix with a perfect output (you won't see thin white lines as you see with hhline). However, nicematrix provides no breakable environment.

\documentclass[10pt]{article}
\usepackage{xcolor}
\usepackage{nicematrix,tikz}

\NiceMatrixOptions
 {
   custom-line = 
    {
      command = doubleline ,
      tikz = 
       { 
         draw = red , 
         double = blue , 
         shorten < = 0.5 \arrayrulewidth ,
         shorten > = 0.5 \arrayrulewidth ,
       } ,
      total-width = 3 \arrayrulewidth  ,
    }
 }

\begin{document}

\begin{NiceTabular}{|ccc|}[rules/color=red]
one & two & three \\
four & five & six \\
\doubleline
seven & eight & nine \\
ten & eleven & twelve \\
\end{NiceTabular}

\end{document}

You need several compilations (because nicematrix uses PGF/Tikz nodes under the hood).