[design] improve head item margins

Author: zombieFox

index.html

@@ -30,10 +30,10 @@
 
 <divclass="grid-item-head">
 <divclass="head">
-<divclass="head-item mb-3 mb-md-0">
+<divclass="head-item mb-3 mb-lg-0">
 <pclass="clock"></p>
 </div>
-<divclass="head-item head-search mb-3 mb-md-0">
+<divclass="head-item head-search mb-3 mb-lg-0">
 <formclass="search" action="http://www.google.com/search" method="get">
 <inputclass="search-input mb-0" type="text" placeholder="Find bookmarks or search" tabindex="1" name="q" autocomplete="off" tabindex="1">
 <inputtype="submit" value="Search" class="is-hidden">
@@ -42,17 +42,17 @@
 <spanclass="icon-close"></span>
 </button>
 </div>
-<divclass="head-item mb-3 mb-md-0">
+<divclass="head-item mb-3 mb-lg-0">
 <buttonclass="button mb-0 control-add" tabindex="1">
 <spanclass="button-text">Add</span>
 </button>
 </div>
-<divclass="head-item mb-3 mb-md-0">
+<divclass="head-item mb-3 mb-lg-0">
 <buttonclass="button mb-0 control-edit" tabindex="1">
 <spanclass="button-text">Edit</span>
 </button>
 </div>
-<divclass="head-item mb-3 mb-md-0">
+<divclass="head-item mb-3 mb-lg-0">
 <formclass="theme">
 <labelclass="button mb-0 theme-label" for="accent-picker">
 <spanclass="button-text">Accent</span>