Nivo Slider margin-top -30px

Nivo slider custom.css

@media all and (max-width: 1000px) {
.theme-custom {
  max-width: 600px;
  margin: -20px auto 40px;
}
.theme-custom .nivo-directionNav {
  display: none;
}
}

@media all and (min-width: 1001px) {
.theme-custom {
  margin: -30px 0 60px;
}

I thing it should be in the default theme css and not as part of the nivo slider.
this way all new themes should be build according to the negative margin.