fixed overlap issue with background color, fixed image sizing

style.css

@@ -8,6 +8,16 @@
   box-sizing: border-box;
 }
 
+#header {
+  display: flex;
+  align-items: center;
+  justify-content: center;
+}
+
+#logo {
+  width: 290px;
+  height: 82px;
+}
 body {
   min-width: 290px;
   background-color: #2b5b84;
@@ -17,7 +27,7 @@ body {
 }
 
 main {
-  margin-left: 310px;
+  margin-left: 400px;
   padding: 20px;
 }
 
@@ -27,7 +37,7 @@ main {
   min-width: 290px;
   top: 0px;
   left: 0px;
-  width: 300px;
+  width: 400px;
   height: 100%;
   border-right: solid;
 }
@@ -81,20 +91,22 @@ a:hover {
 @media (max-width: 815px) {
   #navbar {
     display: block;
-    position: absolute;
+    position: fixed;
     top: 0;
     padding: 0;
     margin: 0;
     width: 100%;
-    max-height: 275px;
+    max-height: 350px;
     border: none;
     z-index: 1;
+    background-color: #2b5b84;
   }
   #main-doc {
     display: block;
     position: relative;
     margin-left: 0px;
-    margin-top: 270px;
+    margin-top: 325px;
+    
   }
 }