Modify the description

* Remove unnecessary code lines in the example
* Rename the id of the heading

Author: Jihye Hong

css-nav-1/Overview.bs

@@ -1132,7 +1132,7 @@ follow the following steps:
 <h2 id=declarative>
 Controlling spatial navigation through declarative means</h2>
 
-<h3 id=container>
+<h3 id=css-property-spatialnavigationcontain>
 Creating additional spatial navigation containers: the 'spatial-navigation-contain' property</h3>
 
 <pre class='propdef'>
@@ -1250,7 +1250,7 @@ Note: the 'spatial-navigation-contain' property is <a>at-risk</a>.
 
 </div>
 
-<h3 id=container>
+<h3 id=css-property-spatialnavigationaction>
 Defining the spatial navigation behavior : the 'spatial-navigation-action' property</h3>
 
 <pre class='propdef'>
@@ -1273,10 +1273,7 @@ the proper spatial navigation behavior.
         Else, the focus moves to the candidates in the viewport.
 
     <dt><dfn>focus</dfn>
-    <dd>If the element is a <a>scroll container</a>,
-        then directional input moves the focus to the candidates(visible or not). The user cannot manually scroll the container.
-
-        Else, the focus moves to the candidates in the viewport.
+    <dd>The directional input moves the focus to the candidates(visible or not). The user cannot manually scroll the container.
 
     NOTE: If the 'focus' value is given to 'spatial-navigation-action', 'navnotarget' event occurs 
     when there isn’t any visible candidate in the spatial navigation container no matter what it can be scrolled more or not.
@@ -1294,7 +1291,7 @@ Pressing the down arrow key moves the focus directly to it without scrolling man
 
     <figure>
         <img alt="" src="images/spatnav-action.png" style="width: 500px;"/>
-        <figcaption>Moving focus to the element without manually scrolling</figcaption>
+        <figcaption>Moving focus to "Box 3" from "Box 2" without manually scrolling</figcaption>
     </figure>
 
     <pre><code highlight=markup>
@@ -1323,21 +1320,6 @@ Pressing the down arrow key moves the focus directly to it without scrolling man
             background-color: red;
         }
     </code></pre>
-    <pre><code highlight=js>
-        let container = document.getElementById('feed');
-        let currentTarget = document.activeElement;
-
-        container.addEventListener('navnotarget', function(e) {
-            e.preventDefault();
-
-            let nextFocus = currentTarget.spatialNavigationSearch({
-                                            dir:  e.dir, 
-                                            this.focusableAreas({'mode': 'all'})
-                                            });
-            
-            nextFocus.focus();
-        });
-    </code></pre>
 
 </div>