Vertical Kerning Between the Footnoteline and First Footnote in a Tikzpicture

Question

This is related to How to Change the Color of the Footnoteline and Footnotemark Beneath within a Tikzpicture

Consider the code

\documentclass[12pt]{book}
\textwidth=5in \textheight=3.50in 
\usepackage[sfdefault]{cabin} 
\usepackage{lipsum}
\usepackage{csquotes}
\usepackage{xcolor}
\definecolor{bblue}{RGB}{33,41,88}
\usepackage{tikz}
\usetikzlibrary{decorations.pathmorphing}
\renewcommand{\thefootnote}{\fnsymbol{footnote}}

\let\ltxfootnoterule\footnoterule
\renewcommand\footnoterule{%
  \ltxfootnoterule
  \kern 5pt% back up
}

\begin{document}
\thispagestyle{empty}

Some text with a footnote.\footnote{Footnote for the text.}

\begin{center}
\begin{tikzpicture}[pencildraw/.style={ %
    /utils/exec=\renewcommand\footnoterule{\color{white}\rule{.3\linewidth}{0.8pt}},
    decorate,
    decoration={random steps,segment length=2pt,amplitude=1pt}
    } %
]
\node[
preaction={fill=black,opacity=0.5,transform canvas={xshift=1mm,yshift=-1mm}},
pencildraw,draw,fill=bblue,text=white,text width=1.00\textwidth,inner sep=2.5mm,align=justify] 
{\fontsize{11.5}{14}\selectfont {\bfseries \enquote{How to increase the vertical space between the footnoteline and the (first) footnote?\footnote{\textcolor{white}{Tikz footnote.}}} \par}};
\end{tikzpicture}
\end{center}
\end{document}

which produces

I would like to increase the vertical space between the footnoteline and the first footnote in the tikzpicture.

Outside of the tikzpicture, this can be accomplished, for example, as follows:

 \let\ltxfootnoterule\footnoterule
\renewcommand\footnoterule{%
  \ltxfootnoterule
  \kern 5pt% back up
}

which seems to work well for the text footnote outside of the tikzpicture. But, the above macro appears to have no effect for the footnote within the tikzpicture.

QUESTION: How may I adjust (increase, in this case) the vertical kerning between the footnoteline and the first (only, in this case) footnote within the tikzpicture? Remark: I do not want to affect the kerning for the footnote outside of the picture, which is being handled separately by the above macro.

Thank you.

Answer 1

You can change the length of \footnotesep inside the tikz picture.

For example using \addtolength{\footnotesep}{<lenght>} (2mm in the example)

\documentclass[12pt]{book}
\textwidth=5in \textheight=3.50in 
\usepackage[sfdefault]{cabin} 
\usepackage{lipsum}
\usepackage{csquotes}
\usepackage{xcolor}
\definecolor{bblue}{RGB}{33,41,88}
\usepackage{tikz}
\usetikzlibrary{decorations.pathmorphing}
\renewcommand{\thefootnote}{\fnsymbol{footnote}}

\let\ltxfootnoterule\footnoterule
\renewcommand\footnoterule{%
    \ltxfootnoterule
    \kern 5pt% back up
}

\begin{document}
    \thispagestyle{empty}
    
    Some text with a footnote.\footnote{Footnote for the text.}
    
    \begin{center}
        \begin{tikzpicture}[pencildraw/.style={ % changed <<<<<<<<<<<<<
                /utils/exec=\addtolength{\footnotesep}{2mm}\renewcommand\footnoterule{\color{white}\rule{.3\linewidth}{0.8pt}},
                decorate,   decoration={random steps,segment length=2pt,amplitude=1pt}}%
            ]
            \node[
            preaction={fill=black,opacity=0.5,transform canvas={xshift=1mm,yshift=-1mm}},
            pencildraw,draw,fill=bblue,text=white,text width=1.00\textwidth,inner sep=2.5mm,align=justify] 
            {\fontsize{11.5}{14}\selectfont {\bfseries \enquote{How to increase the vertical space between the footnoteline and the (first) footnote?\footnote{\textcolor{white}{Tikz footnote.}}} \par}};
        \end{tikzpicture}
    \end{center}

\end{document}