Conditional Formatting a Date Column

For your requirements, you have to use the Column formatting in SharePoint. Follow steps given here in official documentation to open column formatting settings & add below JSON code.

You can use simple JSON like below to format your date columns:

{
    "$schema": "https://developer.microsoft.com/json-schemas/sp/v2/column-formatting.schema.json",
    "elmType": "div",
    "txtContent": "@currentField",
    "attributes": {
        "class": "=if(Number(@currentField) == 0, 'sp-field-severity--blocked', 'sp-field-severity--good')"
    }
}

Output:

See other ways to check if date column is empty at: SharePoint JSON formatting: Check if date & time column is blank/empty

Official documentation: Use column formatting to customize SharePoint

You can use column formatting to meet your needs in SharePoint Online.

Please following steps:

1.Go to the list as a site admin

2.Select the "Date and time" column >> Column settings >> Format this column

3.On the Format Column windows, click on "Advanced mode" link

4.Please use the below JSON code

{
  "$schema": "https://developer.microsoft.com/json-schemas/sp/v2/column-formatting.schema.json",
  "elmType": "div",
  "txtContent": "@currentField",
  "attributes": {
    "class": "=if(Number(@currentField) == 0, 'sp-field-severity--blocked','sp-field-severity--good')"
  }
}

5.Click "Save"