How to get rid of Dotted lines on the sidebar

Go to Customize Click Edit HTML, Look under the post area and you will find the following..

.sidebar .widget, .main .widget {
border-bottom:0px dotted $bordercolor;
margin:0 0 1.5em;
padding:0 0 1.5em;
}

Now all you need to do is change the 1px to 0px
Preview before Saving template.
Any problems, give me a shout.