[Ramses505]

I have an ePub file where I have adjusted the line spacing by editing an entry in the 'stylesheet.css' from this;
.calibre5 {
font-family: "Calibri", "sans-serif";
font-size: 1.33333em;
}

to this;
.calibre5 {
font-family: "Calibri", "sans-serif";
font-size: 1.33333em;
line-height: 2.0em
}

Adding the line-height modifier and checking that the text in the file preview looks something like I am after. However, after converting the file to a MOBI format, the spacing of the lines in the paragraghs of text are not changed from how they were before I adjusted them in the ePub file. When I go back to the ePub file, my edits show and the paragraph text spacing still looks correct as per my edits.

What is happening and how can I maybe get things to look the way I need them ?

Thanks for reading and any helpful suggestions.