- Top Navigation (almost systems): the height of the first level navigation `64px`, the second level of navigation `48px`。
- Top Navigation(contents page): the height of the first level navigation `80px`,the second level of navigation `56px`。
- Calculation formula of a top navigation:`48+8n`.
- Calculation formula a aside navigation:`200+8n`.
### The principle of interaction
- The first level navigation and the last level navigation should be distincted by visualization;
- The current item should have the highest priority of visualization;
- When the current navigation item is collapsed, the stlye of the current navigation item will be applied to the parent level of it;
- The left side navigation bar support for both the according and the expanding style, you can choose the one of it case by case.
### The principle of visualization
Style of a navigation should conform to the level of it.
- **Emphasis by colorblock**
When background color is a deep color, you can use this pattern for the parent level navigation item of current page.
- **The highlight match stick**
When background color is a light color, you can use this pattern for the current page navigation item, we recommed to use it for the last item of the navigation path.
- **Hightlighted font**
From the visualization aspect, hightlighted font is stronger than colorblock, this pattern is often used for the parent level of the current item.
- **Enlarge the size of the font**
`12px`、`14px` is a standard font size of navigations,14 is used for the first and the second level of the navigation. You can choose a approprigate font size in terms of the level of your navigation.
In almost middle-back systems, Ant Design uses two general layouts of top navigation and aside navition, we collect some basic layouts of middle-back systems are designed by Ant Design as follows. The demo code below is used of sample, you should [Layout](/components/layout/) component in real project.