Add bookmark item search (#15)

- Implement form styling throughout
- Modify header links for narrower views
- Clean up CSS

src/public/feed/index.php

@@ -61,7 +61,8 @@ page_head($title); ?>
         <label>
             Feed URL
             <input type=url name=url required autofocus value="<?=$feed['url']?>">
-        </label><br>
+        </label>
+        <span class=break></span>
         <button type=submit>Save</button>
     </form>
 </article><?php