Kindle: How Can I Set Font To Bold

[wander]

For my Kindle, converted a scanned book from RTF to MOBI. The conversion is successful, but I would like to have all of the converted text bolded. (After converting, copied the resultibg .MOBI and .OPF files to my Kindle)

On one forum post there was an instruction to enter

body { font-weight: bold; }

in the "Extra CSS" column of the "Look & Feel" section of the "Convert books" function.

I did that, but the converted output is not bolded. This means that I have not done something else to make the "body" statement work, but I cannot see what it is. (I tried removing the ; after "body", but did not make any difference.)

After converting, copied the resultibg .MOBI and .OPF files to my Kindle
Will appreciate any help.