How can I reduce the space between 2 blocks in TikZposter?

Question

Hi all I have this code and I would like to reduce the space between block, in horizontal and in vertical, and I also would like to optimize the space inside block reducing empty space on lateral side.

\documentclass[a2paper]{tikzposter}
    %\geometry{paperwidth=1080px,paperheight=1980px}
    \usepackage{multicol}
    \usetheme{Board}
    \usepackage{lipsum}
    
    \begin{document}
    
    \node[above right,opacity=1.2,inner sep=0pt,outer sep=0pt] at (bottomleft) {\includegraphics[width=\paperwidth,height=\paperheight]{example-image-duck}};
    
    \maketitle[titletotopverticalspace=-8cm] % See Section 4.1
    \colorlet{blockbodybgcolor}{black}
    \colorlet{blockbodyfgcolor}{white}
    \colorlet{blocktitlefgcolor}{red}
    \block{\textbf{Ultrastructural anylisis}}{}
    
    \begin{columns}
    \column{0.55} 
    \block{\large Scientific Relevance}{
    \small The overall \textcolor{red}{why is this outside?mmmmmmmmmmmmmmmmmm}}
    
    \column{0.45} \block{Ciao}{\lipsum[1]}
    \end{columns}
    
    \end{document}

Answer 1

The tikzposter class has a class option to adjust the space between the columns:

\documentclass[a2paper,colspace=1pt]{tikzposter}
\usetheme{Board}
\usepackage{lipsum}

\begin{document}

\node[above right,opacity=1.2,inner sep=0pt,outer sep=0pt] at (bottomleft) {\includegraphics[width=\paperwidth,height=\paperheight]{example-image-duck}};

\maketitle[titletotopverticalspace=-8cm] % See Section 4.1
\colorlet{blockbodybgcolor}{black}
\colorlet{blockbodyfgcolor}{white}
\colorlet{blocktitlefgcolor}{red}
\block{\textbf{Ultrastructural anylisis}}{}

\begin{columns}
\column{0.55} 
\block{\large Scientific Relevance}{
\small The overall \textcolor{red}{why is this outside?mmmmmmmmmmmmmmmmmm}}

\column{0.45} \block{Ciao}{\lipsum[1]}
\end{columns}

\end{document}