Conditional Formatting using JSON

I have this code which is working great, however, every time I make a change to add in that if it is blank it should be light coral as well - 

here is the original - 

{ "$schema": "https://developer.microsoft.com/json-schemas/sp/v2/column-formatting.schema.json", "elmType": "div", "txtContent": "@currentField", "style": { "background-color": "=if((Number([$Emp_x0020_Returns_x0020_OF306]) - Number([$LP_x0020_Sends_x0020_OF306])) / (1000 * 60 * 60 * 24) == 0, 'LightGreen', if((Number([$Emp_x0020_Returns_x0020_OF306]) - Number([$LP_x0020_Sends_x0020_OF306])) / (1000 * 60 * 60 * 24) <= 10, 'LightGreen', if((Number([$Emp_x0020_Returns_x0020_OF306]) - Number([$LP_x0020_Sends_x0020_OF306])) / (1000 * 60 * 60 * 24) >= 11 && (Number([$Emp_x0020_Returns_x0020_OF306]) - Number([$LP_x0020_Sends_x0020_OF306])) / (1000 * 60 * 60 * 24) <= 20, 'LightYellow', if((Number([$Emp_x0020_Returns_x0020_OF306]) - Number([$LP_x0020_Sends_x0020_OF306])) / (1000 * 60 * 60 * 24) > 20, 'LightCoral', '')))", "color": "black", "padding": "5px", "border-radius": "5px" } }

Here is the new attempt at adding in a null value is also Light Coral. 

{
  "$schema": "https://developer.microsoft.com/json-schemas/sp/v2/column-formatting.schema.json",
  "elmType": "div",
  "txtContent": "@currentField",
  "style": {
    "background-color": "=if(isBlank([$Emp_x0020_Returns_x0020_OF306]) || isBlank([$LP_x0020_Sends_x0020_OF306]), 'LightCoral', if((Number([$Emp_x0020_Returns_x0020_OF306]) - Number([$LP_x0020_Sends_x0020_OF306])) / (1000 * 60 * 60 * 24) <= 10, 'LightGreen', if((Number([$Emp_x0020_Returns_x0020_OF306]) - Number([$LP_x0020_Sends_x0020_OF306])) / (1000 * 60 * 60 * 24) >= 11 && (Number([$Emp_x0020_Returns_x0020_OF306]) - Number([$LP_x0020_Sends_x0020_OF306])) / (1000 * 60 * 60 * 24) <= 20, 'LightYellow', if((Number([$Emp_x0020_Returns_x0020_OF306]) - Number([$LP_x0020_Sends_x0020_OF306])) / (1000 * 60 * 60 * 24) > 20 || isBlank([$Emp_x0020_Returns_x0020_OF306]) || isBlank([$LP_x0020_Sends_x0020_OF306]), 'LightCoral', '')))))",
    "color": "black",
    "padding": "5px",
    "border-radius": "5px"
  }
}

It just makes everything transparent.  Any help would be highly appreciated!  Too bad this isn't built in functionality.