Каскадная (1024-800-640) ширина основного раздела

style/main.css

@@ -3,7 +3,7 @@ html, body {
 }
 
 .mainContainer {
-    width: 85%;
+    width: 1024px;
     margin: auto;
     min-height: 100%;
 }
@@ -200,13 +200,116 @@ img, iframe {
     max-width: 100%;
 }
 
-@media only screen and (max-width : 640px) {
+@media only screen and (max-width : 1024px) {
     nav {
         display: block;
         overflow: hidden;
         background-color: #93ff83;
     }
 
+    .mainContainer {
+   	 width: 968px;
+    }    
+
+
+    .mainContainer > nav > a {
+        margin: 10px;
+    }
+
+    .mainContainer > nav > a > div {
+        transform: initial;
+        top: 0;
+        position: static;
+    }
+
+    .floatRight {
+        float: none;
+    }
+
+    .mainContainer img,
+    .mainContainer iframe {
+        margin: 15px 0;
+    }
+}
+
+
+
+
+@media only screen and (max-width : 968px) {
+    nav {
+        display: block;
+        overflow: hidden;
+        background-color: #93ff83;
+    }
+
+    .mainContainer {
+   	 width: 800px;
+    }    
+
+
+    .mainContainer > nav > a {
+        margin: 10px;
+    }
+
+    .mainContainer > nav > a > div {
+        transform: initial;
+        top: 0;
+        position: static;
+    }
+
+    .floatRight {
+        float: none;
+    }
+
+    .mainContainer img,
+    .mainContainer iframe {
+        margin: 15px 0;
+    }
+}
+
+@media only screen and (max-width : 800px) {
+    nav {
+        display: block;
+        overflow: hidden;
+        background-color: #93ff83;
+    }
+
+    .mainContainer {
+   	 width: 640px;
+    }    
+
+
+    .mainContainer > nav > a {
+        margin: 10px;
+    }
+
+    .mainContainer > nav > a > div {
+        transform: initial;
+        top: 0;
+        position: static;
+    }
+
+    .floatRight {
+        float: none;
+    }
+
+    .mainContainer img,
+    .mainContainer iframe {
+        margin: 15px 0;
+    }
+}
+
+
+@media only screen and (max-width : 640px) {
+    nav {
+        display: block;
+        overflow: hidden;
+        background-color: #93ff83;
+    }
+
+    .mainContainer {
+   	 width: 600px;
+    }    
     .mainContainer > nav > a {
         margin: 10px;
     }