feat: 增加动态登录页背景

src/pages/Login/index.scss

@@ -2,12 +2,20 @@
   width: 100%;
   height: 100%;
   background: linear-gradient(#192948, #33425b);
+  .login-content.bg-1 {
+    background: url('../../assets/img/undraw_all_the_data_h4ki.svg') no-repeat;
+  }
+  .login-content.bg-2 {
+    background: url('../../assets/img/undraw_order_a_car_3tww.svg') no-repeat;
+  }
+  .login-content.bg-3 {
+    background: url('../../assets/img/undraw_work_chat_erdt.svg') no-repeat;
+  }
   .login-content {
     position: relative;
     display: inline-block;
     width: 100%;
     height: 100%;
-    background: url('../../assets/img/undraw_contract_uy56.svg') no-repeat;
     background-position: 25% 95%;
     background-size: 35% auto;
     .form-sign {

src/pages/Login/index.tsx

@@ -134,7 +134,7 @@ const Login = (props: RouteComponentProps) => {
   const { history } = props
   return (
     <div className="login-container">
-      <div className="login-content">
+      <div className={[ "login-content", `bg-${Math.ceil(Math.random() * 10) % 3 + 1}` ].join(' ')}>
         <div className="form-sign pi-flex pi-flex-row">
           <div className="pi-flex-sub">
             <img src={logo} />