\begin{table}
\centering
\begin{tblr}[         %% tabularray outer open
]                     %% tabularray outer close
{                     %% tabularray inner open
colspec={Q[]Q[]Q[]Q[]},
hline{1}={1-4}{solid, white, 0.5em},
hline{2}={1-4}{solid, white, 0.5em},
hline{3}={1-4}{solid, white, 0.5em},
vline{1}={1-2}{solid, white, 0.5em},
vline{2}={1-2}{solid, white, 0.5em},
vline{3}={1-2}{solid, white, 0.5em},
vline{4}={1-2}{solid, white, 0.5em},
vline{5}={1-2}{solid, white, 0.5em},
column{1-4}={}{fg=white, bg=c0000FF},
}                     %% tabularray inner close
\tinytableDefineColor{c0000FF}{HTML}{0000FF}
1 & 3 & 5 & 7 \\
2 & 4 & 6 & 8 \\
\end{tblr}
\end{table} 
