add fixed sider

components/layout/demo/fixed-sider.md

@@ -0,0 +1,92 @@
+---
+order: 7
+iframe: 360
+title:
+  zh-CN: 固定侧边栏
+  en-US: Fixed Sider
+---
+
+## zh-CN
+
+当内容较长时，使用固定侧边栏可以提供更好的体验。
+
+## en-US
+
+In dealing with long content, a fixed sider can provide a better user experience.
+
+````jsx
+import { Layout, Menu, Icon } from 'antd';
+const { Header, Content, Footer, Sider } = Layout;
+
+ReactDOM.render(<Layout style={{ height: '100vh' }}>
+  <Sider style={{ overflow: 'auto' }}>
+    <div className="logo" />
+    <Menu theme="dark" mode="inline" defaultSelectedKeys={['4']}>
+      <Menu.Item key="1">
+        <Icon type="user" />
+        <span className="nav-text">nav 1</span>
+      </Menu.Item>
+      <Menu.Item key="2">
+        <Icon type="video-camera" />
+        <span className="nav-text">nav 2</span>
+      </Menu.Item>
+      <Menu.Item key="3">
+        <Icon type="upload" />
+        <span className="nav-text">nav 3</span>
+      </Menu.Item>
+      <Menu.Item key="4">
+        <Icon type="bar-chart" />
+        <span className="nav-text">nav 4</span>
+      </Menu.Item>
+      <Menu.Item key="5">
+        <Icon type="cloud-o" />
+        <span className="nav-text">nav 5</span>
+      </Menu.Item>
+      <Menu.Item key="6">
+        <Icon type="appstore-o" />
+        <span className="nav-text">nav 6</span>
+      </Menu.Item>
+      <Menu.Item key="7">
+        <Icon type="team" />
+        <span className="nav-text">nav 7</span>
+      </Menu.Item>
+      <Menu.Item key="8">
+        <Icon type="shop" />
+        <span className="nav-text">nav 8</span>
+      </Menu.Item>
+    </Menu>
+  </Sider>
+  <Layout>
+    <Header style={{ background: '#fff', padding: 0 }} />
+    <Content style={{ margin: '24px 16px 0', overflow: 'initial' }}>
+      <div style={{ padding: 24, background: '#fff', textAlign: 'center' }}>
+        ...
+        <br />
+        Really
+        <br />...<br />...<br />...<br />
+        long
+        <br />...<br />...<br />...<br />...<br />...<br />...
+        <br />...<br />...<br />...<br />...<br />...<br />...
+        <br />...<br />...<br />...<br />...<br />...<br />...
+        <br />...<br />...<br />...<br />...<br />...<br />...
+        <br />...<br />...<br />...<br />...<br />...<br />...
+        <br />...<br />...<br />...<br />...<br />...<br />...
+        <br />...<br />...<br />...<br />...<br />...<br />
+        content
+      </div>
+    </Content>
+    <Footer style={{ textAlign: 'center' }}>
+      Ant Design ©2016 Created by Ant UED
+    </Footer>
+  </Layout>
+</Layout>, mountNode);
+````
+
+````css
+#components-layout-demo-fixed-sider .logo {
+  height: 32px;
+  background: #333;
+  border-radius: 6px;
+  margin: 16px;
+}
+````