Pgfplots：用不同颜色进行阴影处理

Question

我有这张照片：

它是使用此代码生成的：

\documentclass[border=5mm]{standalone}
\usepackage{pgfplots}
\pgfplotsset{width=10cm,compat=1.14, label style={font=\huge}, tick label style={font=\huge}}
\usepgfplotslibrary{fillbetween}
\begin{document}

\pgfmathdeclarefunction{gauss}{2}{%
  \pgfmathparse{1/(#2*sqrt(2*pi))*exp(-((x-#1)^2)/(2*#2^2))}%
}

\begin{tikzpicture}
\begin{axis}[
  no markers, domain=-4:4, samples=100,
  axis x line=bottom, axis y line=left,
  every axis y label/.style={at=(current axis.above origin),anchor=south},
  every axis x label/.style={at=(current axis.right of origin),anchor=west},
  height=5cm, width=16cm,
  xtick={-3, -2, -1, 0, 1, 2, 3}, ytick=\empty,
  enlargelimits=false, clip=false, axis on top,
  xticklabels={-3, -2, -1, 0, 1, 2, 3}, %  so do it manually instead
  ]

  \addplot [very thick,black, name path=f] {gauss(0,1)};



    \path[name path=axis](axis cs:-2,0) -- (axis cs:-1,0);
    \addplot[thick, color=blue, fill=blue, fill opacity=0.5] fill between [of=f and axis, soft clip={domain=-2:-1},];

       \path[name path=axis](axis cs:1,0) -- (axis cs:2,0);
    \addplot[thick, color=blue, fill=blue, fill opacity=0.5] fill between [of=f and axis, soft clip={domain=1:2},];

         \path[name path=axis](axis cs:-3,0) -- (axis cs:-2,0);
    \addplot[thick, color=yellow, fill=yellow, fill opacity=0.5] fill between [of=f and axis, soft clip={domain=-3:-2},];

        \path[name path=axis](axis cs:2,0) -- (axis cs:3,0);
    \addplot[thick, color=yellow, fill=yellow, fill opacity=0.5] fill between [of=f and axis, soft clip={domain=2:3},];

        \path[name path=axis](axis cs:-1,0) -- (axis cs:1,0);
    \addplot[thick, color=red, fill=red, fill opacity=0.5] fill between [of=f and axis, soft clip={domain=-1:1},];
\end{axis}

\end{tikzpicture}
\end{document}

我想去掉那个白色三角形。也就是说，从 -1 到 1 的区域应该全部是红色。

我如何获得它？

作为备份，如果这不起作用，在 (-1, 1) 处进行红色处理并在 (-2, 2) 处进行红色与蓝色重叠以及在 (-3, 3) 处进行红色和蓝色与黄色重叠也有效（甚至可能更好...）