rounding error on some browser, now flexible if we add/remove items

ippisite/ippidb/static/css/admin-session.css

@@ -18,14 +18,20 @@ Description: IPPI-DB Theme
 .step_nav ul {
   margin: 0 ;
   padding: 0;
+  display:flex;
 }
 
 .step_nav li {
   display: inline;
+  flex:1 auto;
+}
+
+.step_nav li:not(:first-child) {
+  padding-left: 5px;
 }
 
 .step_nav li a, .step_nav  li a:hover, .step_nav li a:focus {
-  width: 12.19%;
+  width: 100%;
   background-color: #E3E9EB;
   color:#8D8888;
   font-family: "PlayfairDisplayReg";