Flattening the Archive Lists in Blogger

.BlogArchive #ArchiveList ul ul li {padding-left: 0;}

.sidebar li {
text-indent: 0;
padding-left: 0;
}

.BlogArchive #ArchiveList ul li {
padding-left: 0;
text-indent: 0;
}

.BlogArchive #ArchiveList ul.posts li {padding-left: 0;}

To change spacing between the list elements:

.sidebar li {margin: 0 0 1em 0;}