Fix markdown syntax

README.md

@@ -1,52 +1,56 @@
 # ETNavBarTransparent
 Change NavigationBar's transparency at pop gestrue and other situation
-###Screenshots
+
+## Animation
 ![image](https://github.com/EnderTan/ETNavBarTransparentDemo/blob/master/navDemo.gif)
 
-##Installation
+## Installation
 Add the following line to your Podfile:
-```
+```ruby
 pod 'ETNavBarTransparent'
 ```
+
 Then, run the following command:
-```
+```bash
 $ pod install
 ```
 
-Or,Simply drag "ET_NavBarTransparent.swift" to your project
+Or, simply drag `ET_NavBarTransparent.swift` to your project.
+
+## Usage
 
-##Usage
 Change NavigationBar's transparency and tintColor where you want:
-```
-    //Example：
-    //Change in viewDidLoad
+
+```swift
+    // Example：
+    // Change in viewDidLoad
     override func viewDidLoad() {
         super.viewDidLoad()
 
         self.navBarBgAlpha = 0
         self.navBarTintColor = .white
     }
 
-    //Change in scrollView scroll
+    // Change in scrollView scroll
     func scrollViewDidScroll(_ scrollView: UIScrollView) {
 
         if scrollView.contentOffset.y > 100 {
             navBarBgAlpha = 1
             navBarTintColor = UIColor.defaultNavBarTintColor()
-        }else{
+        } else {
             navBarBgAlpha = 0
-            navBarTintColor = UIColor.white
+            navBarTintColor = .white
         }
 
     }
 ```
 
 
-##Related articles
+## Related articles
 [导航栏的平滑显示和隐藏 - 个人页的自我修养（1）](http://www.jianshu.com/p/454b06590cf1)
 
-##License
+## License
 MIT license. See LICENSE for details.
 
-##Contact
+## Contact
 Follow and contact me on Weibo [@日光镇](http://weibo.com/endertan) or [My Blog](http://www.jianshu.com/u/a958e552973b)