styling issue - advised code not working

[es88]

Hello,

First of all. I am loving your plugin. So much nicer than anything out there.
I am struggling to change the style of the tooltip though.

I would really appreciate some help.

//Tooltip
Opentip.styles.tooltip = {

ajax: true, // The URL to download will be taken from the href attribute
showOn: 'mouseover',
target: true, /
tipJoint: "top",
group: "tags" ,
background: "#ffffff",

};

Opentip.defaultStyle = "tooltip"

This is my code and it is not changing the style.
Is there anything I am missing?

Thanks so much,
Eva