<!DOCTYPE html>
<html>
  <body style="width: 0">
    <span style="border: 2px solid blue; border-right: none"></span>
    <span style="display: block"></span>
    <span style="border: 2px solid blue; border-left: none; border-right: none">
      a b
    </span>
    <span style="display: block"></span>
    <span style="border: 2px solid blue; border-left: none;">
      c
    </span>
  </body>
</html>