#search-form-header {
  margin-top: 6px;
}

#masthead {
  z-index: $zindex-navbar + 1;
}

#search-form-header {
  margin-top: 6px;
}

#masthead {
  margin-bottom: 0;
  z-index: $zindex-navbar + 1;
}

Remove bottom margin from sufia masthead navbar
Remove bottom margin from sufia masthead navbar
