refactored all script : replaced onupdate by onbeforeupdate (red more about lifecycle in mithrile)

assets/main.scss

@@ -22,8 +22,13 @@ html, body{
 }
 
 header{
+  position: fixed;
+  width:100%; top:0; z-index: 5;
   >*{
     display: inline-block;
+    vertical-align: top;
+    &:first-child{ margin-left: 1em;}
+    &:last-child{ margin-right: 1em;}
   }
 }
 
@@ -44,18 +49,18 @@ aside#menus{
   }
 }
 
-#app{
-  position: relative;
-  text-align: center;
-  margin: 0 auto;
-}
+// #app{
+//   position: relative;
+//   text-align: center;
+//   margin: 3em auto;
+// }
 
 main#content{
-  display:inline-block;
-  text-align: left;
-  // &>*{
-  //   width: 450px;
-  // }
+  margin: 3em auto;
+  width: 450px;
+  &>*{
+    width: 450px;
+  }
 }
 
 h1.part{
@@ -114,3 +119,9 @@ section.enonce{
 
   }
 }
+
+footer{
+  position: fixed;
+  bottom: 0;
+  >*{margin-left: 1em;}
+}