Fit coloured longtable to pagewidth

Question

There is a similar question and solution posted here. However, I can't use this solution as I have a coloured table, and the given solution causes white gaps between each column.

Is there a way to fit a coloured long table to the width of a page (including landscape pages) so that the row colouring is maintained?

Here is an example of my current code:

\documentclass{article}

\usepackage[table]{xcolor}
\usepackage{float}
\usepackage{array}
\usepackage{longtable}

\restylefloat{table}

\definecolor{Gray}{gray}{0.65}
\definecolor{Blue}{RGB}{0,176,240}
\definecolor{light-gray}{gray}{0.90}

% Margins
\topmargin=-0.45in
\evensidemargin=0in
\oddsidemargin=0in
\textwidth=6.5in
\textheight=8.5in
\headsep=0.25in 

\linespread{1.1} % Line spacing

\newcommand{\specialcell}[2][c]{\begin{tabular}[#1]{@{}c@{}}#2\end{tabular}}
\newcommand\setrowfont[1]{\noalign{\gdef\rowfont{#1}}}
\gdef\rowfont{}

\makeatletter
\newcommand*{\@rowstyle}{}

\newcommand*{\rowstyle}[1]{% sets the style of the next row
  \gdef\@rowstyle{#1}%
  \@rowstyle\ignorespaces%
}

\newcolumntype{=}{% resets the row style
  >{\gdef\@rowstyle{}}%
}

\newcolumntype{+}{% adds the current row style to the next column
  >{\@rowstyle}%
}
\newcolumntype{C}{>{\rowfont}c}

\let\oldlongtable\longtable
\let\endoldlongtable\endlongtable
\renewenvironment{longtable}{\rowcolors{2}{light-gray}{Gray}\oldlongtable} {
\endoldlongtable}

\begin{document}

% Normal
\setlength\LTcapwidth{\textwidth}
\setlength\LTleft{-10cm plus -1fill}
\setlength\LTright{\LTleft}
\begin{longtable}{=C+C+C}
\rowcolor{Blue} 
\rowstyle{\color{white}}
A & B & C \\
1 & 2 & 3 \\
4 & 5 & 6 \\
7 & 8 & 9 \\
\end{longtable}

% To page width but has white gaps between columns
\setlength\LTcapwidth{\textwidth}
\setlength\LTleft{0pt}
\setlength\LTright{0pt}
\begin{longtable}{@{\extracolsep{\fill}}=C+C+C}
\rowcolor{Blue} 
\rowstyle{\color{white}}
A1 & B1 & C1 \\
1 & 2 & 3 \\
4 & 5 & 6 \\
7 & 8 & 9 \\
\end{longtable}

\end{document}

Generates:

Answer 1

\documentclass{article}

\usepackage[table]{xcolor}
\usepackage{float}
\usepackage{array}
\usepackage{longtable}

\restylefloat{table}

\definecolor{Gray}{gray}{0.65}
\definecolor{Blue}{RGB}{0,176,240}
\definecolor{light-gray}{gray}{0.90}

% Margins
\topmargin=-0.45in
\evensidemargin=0in
\oddsidemargin=0in
\textwidth=6.5in
\textheight=8.5in
\headsep=0.25in 

\linespread{1.1} % Line spacing

\newcommand{\specialcell}[2][c]{\begin{tabular}[#1]{@{}c@{}}#2\end{tabular}}
\newcommand\setrowfont[1]{\noalign{\gdef\rowfont{#1}}}
\gdef\rowfont{}

\makeatletter
\newcommand*{\@rowstyle}{}

\newcommand*{\rowstyle}[1]{% sets the style of the next row
  \gdef\@rowstyle{#1}%
  \@rowstyle\ignorespaces%
}

\newcolumntype{=}{% resets the row style
  @{\zz}>{\gdef\@rowstyle{}}%
}

\makeatletter
\def\zz{%
{\let\CT@color\color\CT@row@color\leaders\vrule\hskip\textwidth}%
\kern-\textwidth}

\newcolumntype{+}{% adds the current row style to the next column
  >{\@rowstyle}%
}
\newcolumntype{C}{>{\rowfont}c}

\let\oldlongtable\longtable
\let\endoldlongtable\endlongtable
\renewenvironment{longtable}{\rowcolors{2}{light-gray}{Gray}\oldlongtable} {
\endoldlongtable}

\begin{document}


% To page width but has white gaps between columns
\setlength\LTcapwidth{\textwidth}
\setlength\LTleft{0pt}
\setlength\LTright{0pt}
\begin{longtable}{=C@{\extracolsep{\fill}}+C+C@{}}
\rowcolor{Blue} 
\rowstyle{\color{white}}
A1 & B1 & C1 \\
1 & 2 & 3 \\
4 & 5 & 6 \\
7 & 8 & 9 \\
\end{longtable}

\end{document}