generateStyles(className, colors, resize = false) {
      return `
        .${className} {
          background-color: ${colors.background} !important;
          border: 1px dashed transparent;
        }
        .${className}.${STATE_CLASS_MODS.active}:not(.${STATE_CLASS_MODS.hidden}) {
          color: ${colors.activeText} !important;
          background-color: ${resize ? colors.resizeBackground : colors.activeBackground} !important;
        }
      `;
    }
Generate styles for region and active region, but with a lighter background is that's a resized region,
so the selection of the same color will give the original color of active region.
@see getColors
@param {string} className
@param {object} colors see `getColors()`
@param {boolean} resize lighter background for resized region or original one for active region
@returns {string} styles to apply to the region