Use <button> for menu bar (#523)

src/theme/book.css

@@ -145,7 +145,8 @@ table thead td {
   position: relative;
   height: 50px;
 }
-.menu-bar i {
+.menu-bar i,
+.menu-bar .icon-button {
   position: relative;
   margin: 0 10px;
   z-index: 10;
@@ -156,7 +157,8 @@ table thead td {
   -ms-transition: color 0.5s;
   transition: color 0.5s;
 }
-.menu-bar i:hover {
+.menu-bar i:hover,
+.menu-bar .icon-button:hover {
   cursor: pointer;
 }
 .menu-bar .left-buttons {
@@ -322,10 +324,12 @@ table thead td {
 .light .nav-chapters:visited,
 .light .mobile-nav-chapters,
 .light .mobile-nav-chapters:visited,
+.light .menu-bar .icon-button,
 .light .menu-bar a i {
   color: #ccc;
 }
 .light .menu-bar i:hover,
+.light .menu-bar .icon-button:hover,
 .light .nav-chapters:hover,
 .light .mobile-nav-chapters i:hover {
   color: #333;
@@ -405,6 +409,15 @@ table thead td {
 .light pre > .result {
   margin-top: 10px;
 }
+.light .icon-button {
+  border: none;
+  background: none;
+  padding: 0;
+  color: inherit;
+}
+.light .icon-button i {
+  margin: 0;
+}
 .coal {
   color: #98a3ad;
   background-color: #141617;
@@ -443,10 +456,12 @@ table thead td {
 .coal .nav-chapters:visited,
 .coal .mobile-nav-chapters,
 .coal .mobile-nav-chapters:visited,
+.coal .menu-bar .icon-button,
 .coal .menu-bar a i {
   color: #43484d;
 }
 .coal .menu-bar i:hover,
+.coal .menu-bar .icon-button:hover,
 .coal .nav-chapters:hover,
 .coal .mobile-nav-chapters i:hover {
   color: #b3c0cc;
@@ -526,6 +541,15 @@ table thead td {
 .coal pre > .result {
   margin-top: 10px;
 }
+.coal .icon-button {
+  border: none;
+  background: none;
+  padding: 0;
+  color: inherit;
+}
+.coal .icon-button i {
+  margin: 0;
+}
 .navy {
   color: #bcbdd0;
   background-color: #161923;
@@ -564,10 +588,12 @@ table thead td {
 .navy .nav-chapters:visited,
 .navy .mobile-nav-chapters,
 .navy .mobile-nav-chapters:visited,
+.navy .menu-bar .icon-button,
 .navy .menu-bar a i {
   color: #737480;
 }
 .navy .menu-bar i:hover,
+.navy .menu-bar .icon-button:hover,
 .navy .nav-chapters:hover,
 .navy .mobile-nav-chapters i:hover {
   color: #b7b9cc;
@@ -647,6 +673,15 @@ table thead td {
 .navy pre > .result {
   margin-top: 10px;
 }
+.navy .icon-button {
+  border: none;
+  background: none;
+  padding: 0;
+  color: inherit;
+}
+.navy .icon-button i {
+  margin: 0;
+}
 .rust {
   color: #262625;
   background-color: #e1e1db;
@@ -685,10 +720,12 @@ table thead td {
 .rust .nav-chapters:visited,
 .rust .mobile-nav-chapters,
 .rust .mobile-nav-chapters:visited,
+.rust .menu-bar .icon-button,
 .rust .menu-bar a i {
   color: #737480;
 }
 .rust .menu-bar i:hover,
+.rust .menu-bar .icon-button:hover,
 .rust .nav-chapters:hover,
 .rust .mobile-nav-chapters i:hover {
   color: #262625;
@@ -768,6 +805,15 @@ table thead td {
 .rust pre > .result {
   margin-top: 10px;
 }
+.rust .icon-button {
+  border: none;
+  background: none;
+  padding: 0;
+  color: inherit;
+}
+.rust .icon-button i {
+  margin: 0;
+}
 .ayu {
   color: #c5c5c5;
   background-color: #0f1419;
@@ -806,10 +852,12 @@ table thead td {
 .ayu .nav-chapters:visited,
 .ayu .mobile-nav-chapters,
 .ayu .mobile-nav-chapters:visited,
+.ayu .menu-bar .icon-button,
 .ayu .menu-bar a i {
   color: #737480;
 }
 .ayu .menu-bar i:hover,
+.ayu .menu-bar .icon-button:hover,
 .ayu .nav-chapters:hover,
 .ayu .mobile-nav-chapters i:hover {
   color: #b7b9cc;
@@ -889,6 +937,15 @@ table thead td {
 .ayu pre > .result {
   margin-top: 10px;
 }
+.ayu .icon-button {
+  border: none;
+  background: none;
+  padding: 0;
+  color: inherit;
+}
+.ayu .icon-button i {
+  margin: 0;
+}
 @media only print {
   #sidebar,
   #menu-bar,

src/theme/index.hbs

@@ -78,15 +78,19 @@
                 {{> header}}
                 <div id="menu-bar" class="menu-bar">
                     <div class="left-buttons">
-                        <i id="sidebar-toggle" class="fa fa-bars" title="Toggle sidebar"></i>
-                        <i id="theme-toggle" class="fa fa-paint-brush" title="Change theme"></i>
+                        <button id="sidebar-toggle" class="icon-button" type="button" title="Toggle sidebar">
+                            <i class="fa fa-bars"></i>
+                        </button>
+                        <button id="theme-toggle" class="icon-button" type="button" title="Change theme">
+                            <i class="fa fa-paint-brush"></i>
+                        </button>
                     </div>
 
                     <h1 class="menu-title">{{ book_title }}</h1>
 
                     <div class="right-buttons">
-                        <a href="print.html">
-                            <i id="print-button" class="fa fa-print" title="Print this book"></i>
+                        <a href="print.html" title="Print this book">
+                            <i id="print-button" class="fa fa-print"></i>
                         </a>
                     </div>
                 </div>

src/theme/stylus/menu.styl

@@ -2,7 +2,7 @@
     position: relative
     height: 50px
 
-    i {
+    i, .icon-button {
         position: relative
         margin: 0 10px
         z-index: 10

src/theme/stylus/themes/base.styl

@@ -39,11 +39,13 @@
     .nav-chapters:visited,
     .mobile-nav-chapters,
     .mobile-nav-chapters:visited,
+    .menu-bar .icon-button,
     .menu-bar a i {
         color: $icons
     }
 
     .menu-bar i:hover,
+    .menu-bar .icon-button:hover,
     .nav-chapters:hover,
     .mobile-nav-chapters i:hover {
         color: $icons-hover
@@ -132,4 +134,15 @@
         & > .result { margin-top: 10px; }
 
     }
+
+    .icon-button {
+        border: none;
+        background: none;
+        padding: 0;
+        color: inherit;
+
+        i {
+            margin: 0;
+        }
+    }
 }