Change size & colors of list, table, and kanban blocks

Custom Coding
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1

Hi! I am trying this code

#table1 .container { max-width: none; }

above to change the size of my kanban block but am not having success.

I have the code

#kanban1 .card-ul-element{ background: #343434; } #kanban1 .kanban-column{ background: #343434; }

above it in the custom header code area then a blank row then i started the code to change the size below. What am i doing wrong?
Thanks in advance!