You can adjust the following button styles. Remove any line to revert it back it’s default value.

/**
* Pocket View
* Button Styles
* From Will-Myers.com
**/
[data-wm-plugin="pocket-view"] {
  --pocket-button-background: white;
  --pocket-button-title-color: black;
  --pocket-button-description-color: black;

  --pocket-button-active-background: black;
  --pocket-button-active-title-color: white;
  --pocket-button-active-description-color: white;

  --pocket-button-hover-background: black;
  --pocket-button-hover-title-color: white;
  --pocket-button-hover-description-color: white;

  --pocket-button-border-width: 2px;
  --pocket-button-border-type: solid;
  --pocket-button-border-color: black;
  --pocket-button-border-radius: 5px;

  --pocket-button-list-alignment: start;
  --pocket-button-gap: 2px;
  --pocket-button-padding: 10px;
  --pocket-button-text-align: right;
}
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Button Styles (Minimal)