update Card

@muei 更新了一下

examples/routers/card.vue

@@ -1,5 +1,5 @@
 <template>
-    <Card style="width:350px" v-bind:padding="0">
+    <Card style="width:350px">
         <p slot="title">
             <Icon type="ios-film-outline"></Icon>
             经典电影

src/components/card/card.vue

@@ -7,6 +7,7 @@
 </template>
 <script>
     const prefixCls = 'ivu-card';
+    const defaultPadding = 16;
 
     export default {
         props: {
@@ -22,7 +23,10 @@
                 type: Boolean,
                 default: false
             },
-            padding: Number
+            padding: {
+                type: Number,
+                default: defaultPadding
+            }
         },
         data () {
             return {
@@ -51,15 +55,14 @@
                 return `${prefixCls}-body`;
             },
             bodyStyles () {
-                let padding = this.padding;
-                if (this.padding !== undefined) {
-                    padding += 'px';
+                if (this.padding !== defaultPadding) {
                     return {
-                        padding,
-                    };
+                        padding: `${this.padding}px`
                     }
+                } else {
                     return '';
                 }
+            }
         },
         mounted () {
             this.showHead = this.$slots.title !== undefined;