formatting of colon is shifted to the left in a math assignment

[sanderhahn]

The colon in shifted to the left, see screenshot:

$x:=x$

On github:

$x:=x$

Also I needed to add this to the css to hide the unformatted formulas:

    *[aria-hidden="true"] {
      display: none;
    }

Added this to format blocks, but that might be more of a style interpretation:

    .katex-display {
      display: block;
      margin: 1em 0;
      text-align: center;
    }