I am using the following code to set the page:

<style tyle="text/css">
@page { size:8.5in 11in; landscape}
body,  td {
        font-size: 10pt;
}
</style>

but it has no effect at all.

What am I doing wrong?

I changed the code a little and look like the font size has to go down to 6pt:

<style tyle="text/css">
@page { size:8.5in 11in portrait}
</style>

<style tyle="text/css">
body, td {
        font-size: 6pt;
}

When debugging CSS rules it can be handy to use "color: red" or "border: solid red thin" to check if a rule is being applied or not.