style(css): 优化主题颜色和样式

- 更新 primary color 为 #71b73c- 调整输入框焦点边框颜色
- 优化下拉菜单样式
- 统一选择框样式
- 调整按钮样式

src/views/Survey/Index.vue

@@ -59,10 +59,10 @@
           <div>
             <el-button @click="deleteItem(item)"> 删除</el-button>
             <el-button @click="copyItem(item)"> 复制</el-button>
-            <el-button @click="toPreview(item)" style="border: 2px solid #71b73c">
+            <el-button style="border: 2px solid #71b73c" @click="toPreview(item)">
               <el-text style="color: #71b73c">预览</el-text>
             </el-button>
-            <el-button @click="toPublish(item)" color="#6fb937">
+            <el-button color="#6fb937" @click="toPublish(item)">
               <el-text style="color: white">开启投放</el-text>
             </el-button>
           </div>