Siblings not getting on

[cerealkillah]

DD is 17, DS is 20 and they just don't get on. She winds him up and he's rude to her. It's just a cycle that never ends. I dread mealtimes as the sniping always happens. I'm a single parent and their dad doesn't really see them and doesn't get involved in this type of thing. They love their dad, but he's not really acting like a dad, if that makes sense.
I've spoken to them both about how it upsets me. Then they just get cross with me.
I am at my wits end with how to deal with it. We all live under the same roof and I feel I'm walking on eggshells all the times. I don't expect them to be best friends but it'd be nice if they could at least be civil to each other.
Does anyone have any words of advice?

When I reached that age me and my siblings wound each other up all the time. Mum and Dad had firm boundaries which we knew not to cross (within their earshot), otherwise they ignored or used humour to diffuse the situation and make us realise how ridiculous we were being.

If it is any consolation, we got on much better once we left home and weren't in each others space all the time.

My sister and I were like this. Still are. I like her much more when we're nit in each other's pockets.

They need to understand though that it can't carry on at the dinner table or whatever though. My parents would never have tolerated that.

Thanks @helloxhristmas @WeAllHaveWings for the replies.
I've always been strict about table manners. And they know I don't like it when they argue. I like the idea of diffusing it with humour though.
I think I have to accept that while they're under the same roof they probably won't get on.