Add styles for quadrant pages

styles/components/item-page.css

@@ -1,32 +1,39 @@
 .item-page {
   display: flex;
-  height: 100vh;
+  min-height: 100vh;
+  width: 100vw;
+  position: fixed;
+  top: 0;
+  left: 0;
+
   &__nav,
   &__content {
-    height: 100%;
+    box-sizing: border-box;
+    padding-top: 150px;
+    height: 100vh;
+    position: relative;
   }
 
   &__header {
     min-height: 40px;
-    margin: 50px 0 25px;
+    margin: 0 0 25px;
   }
 
   &__nav {
-    flex: 0 0 30%;
-    background: var(--color-gray-dark);
+    flex: 0 0 37%;
     &__inner {
       float: right;
       width: 375px;
-      margin: 60px 40px 0 0;
+      margin: 0 40px 0 0;
     }
   }
 
   &__content {
-    flex: 0 0 70%;
+    flex: 0 0 63%;
     background: var(--color-white);
     &__inner {
       width: 680px;
-      margin: 60px 0 0 110px;
+      margin: 0 0 0 100px;
     }
   }
 }