.inner_column ::selection {
    color: #282c2e;
    background: #c8e0e8;
  }

General advice for web developers: don’t override selection colours for aesthetic reasons, it tends to harm accessibility: https://developer.mozilla.org/en-US/docs/Web/CSS/::selection...

::selection is more or less one of the mistakes of the past that I wish browser makers would agree to kill off. I wish Firefox had at least an about:config switch to disable it.

Nice catch! FWIW on my machine the background is the same but the font changes colors slightly when selected.