Preventing “double” borders in CSS

Question

Say I have two divs next to each other (take https://chrome.google.com/webstore/category/home as reference) with a border.

Is there a way (preferably a CSS trick) to

Answer 1

CSS:

  .one{
    width:100px;
    height:100px;
    border:thin red solid;
    float:left;
  }
.two{
    width:100px;
    height:100px;
    border-style: solid solid solid none;

    border-color:red;
    border-width:1px;
    float:left;
}

jsFiddle ​