better svg namespace declaration https://developer.mozilla.org/en/docs/Web/SVG/Namespaces_Crash_Course
stroke-width under 1 px
a xlink:href in place. plus: cursor:pointer for hover items.
colors in css (fill and stroke).
adding a little css transition for the item-hover
added viewbox, changed default height of items to 40, added a little animation scale(1,1.6)