docs: rewrite README; feat: dark login bg, svg logo, avatar fallback

src/view/login/login.less

@@ -1,9 +1,8 @@
 .login{
     width: 100%;
     height: 100%;
-    background-image: url('../../assets/images/login-bg.jpg');
-    background-size: cover;
-    background-position: center;
+    background-color: #0d0d0d;
+    background-image: linear-gradient(135deg, #0d0d0d 0%, #1a1a1a 100%);
     position: relative;
     &-con{
         position: absolute;

src/view/login/login.vue

@@ -5,17 +5,17 @@
 <template>
     <div class="login">
       <vue-particles
-        color="#dedede"
-        :particleOpacity="0.7"
-        :particlesNumber="80"
+        color="#ffffff"
+        :particleOpacity="0.6"
+        :particlesNumber="60"
         shapeType="circle"
-        :particleSize="4"
-        linesColor="#dedede"
+        :particleSize="3"
+        linesColor="#ffffff"
         :linesWidth="1"
         :lineLinked="true"
-        :lineOpacity="0.4"
+        :lineOpacity="0.3"
         :linesDistance="150"
-        :moveSpeed="3"
+        :moveSpeed="2"
         :hoverEffect="true"
         hoverMode="grab"
         :clickEffect="true"

src/view/sys/sys-user.vue

@@ -152,17 +152,25 @@
             key: 'nickname',
             minWidth: 200,
             render: (h, params) => {
+              const row = params.row
+              const text = (row.nickname || row.username || 'U').trim().charAt(0)
               return h('div',
                 [
                   h('Avatar',
                     {
                       props: {
                         shape: 'square',
-                        src: params.row.avatar
+                        src: row.avatar || ''
+                      },
+                      style: {
+                        marginRight: '8px',
+                        verticalAlign: 'middle',
+                        backgroundColor: '#2d8cf0'
                       }
-                    }
+                    },
+                    text
                   ),
-                  h('span', params.row.nickname)
+                  h('span', row.nickname)
                 ]
               )
             }