Add instruction for setting iconfont size and color, ref #2125

components/icon/index.en-US.md

@@ -64,6 +64,12 @@ ReactDOM.render(<IconSet className="icons" catigory="logo" />, mountNode);
 
 ## API
 
+You can set `style` and `className` for size and color of icons because they are still words in essence.
+
+```jsx
+<Icon type="question" style={{ fontSize: 16, color: '#08c' }} />
+```
+
 | Property | Description      | Type   | Default |
 |----------|------------------|------- |---------|
 | type | Type of ant design icons | string | - |

components/icon/index.zh-CN.md

@@ -65,6 +65,12 @@ ReactDOM.render(<IconSet className="icons" catigory="logo" />, mountNode);
 
 ## API
 
+由于图标字体本质上还是文字，可以使用 `style` 和 `className` 设置图标的大小和颜色。
+
+```jsx
+<Icon type="question" style={{ fontSize: 16, color: '#08c' }} />
+```
+
 | 参数      | 说明             | 类型      | 默认值  |
 |----------|------------------|----------|--------|
 | type | 图标类型 | string | - |