Add menu styles

app/styles/app.css

@@ -1,3 +1,7 @@
+* {
+    box-sizing: border-box;
+}
+
 section {
     float: left;
 }
@@ -7,8 +11,8 @@ section {
 }
 
 .menu {
-    width: 13em;
-    margin-top: 20px;
+    width: 200px;
+    margin: 20px;
 }
 .menu ul {
     margin: 0;
@@ -16,9 +20,8 @@ section {
 }
 li.nav {
     display: block;
-    line-height: 2.5em;
-    padding: 0 1em;
     cursor: pointer;
+    margin-bottom: 5px;
 }
 .nav.empact {
     font-weight: 600;
@@ -27,9 +30,30 @@ li.nav {
     color: #aaa;
     cursor: default;
 }
+.menu a:before {
+    display: block;
+    float: left;
+    width: 3px;
+    height: 32px;
+    border-radius: 3px;
+    background-color: #218c8d;
+    content: '';
+    margin-right: 10px;
+}
+.menu a {
+    display: inline-block;
+    line-height: 32px;
+    width: 100%;
+    color: #222;
+    text-decoration: underline;
+    border-radius: 3px;
+}
+.menu a.active {
+    background-color: #bcdcdc;
+}
 
 .content {
-    width: calc(100% - 13em);
+    width: calc(100% - 240px);
     margin-top: 20px;
 }
 .content .left, .content .right {