N3 — outside your level filter
on top of that — a second circumstance stacked on the first, pulling the same way
昨日、財布を落としてさ。その上、電車まで止まってて最悪だったよ。
kinou, saifu o otoshite sa. sono ue, densha made tomattete saiaku datta yo.
I dropped my wallet yesterday. And on top of that the trains stopped too — it was the worst. casual
この部屋は日当たりがいいです。その上、収納も十分にあるんです。
kono heya wa hiatari ga ii desu. sono ue, shuunou mo juubun ni aru n desu.
This room gets good sunlight. On top of that, there's plenty of storage. neutral
その上
そのうえsono ueN3neutral