feat: system alert message (#3139)

static/style.css

@@ -69,13 +69,7 @@ header {
     margin-top: 40px;
     padding: 15px;
     color: #1182DB;
-}
-
-header > div.logo {
-    background-image: url(logo_600px.png);
-    width: 599px;
-    height: 177px;
-    margin: auto;
+    text-align: center;
 }
 
 section.warning {
@@ -349,6 +343,15 @@ button {
     width: 200px;
 }
 
+.alert {
+    margin-bottom: 15px;
+    color: white;
+    font-weight: bold;
+    background-color: rgb(33, 150, 243);
+    padding: 15px;
+    border-radius: 4px;
+}
+
 @media screen and (max-width: 767px) {
     .container {
         width: 100%;
@@ -359,12 +362,6 @@ button {
         margin-bottom: 5px;
     }
 
-    header > div.logo {
-        background-image: url(logo_300px.png);
-        width: 300px;
-        height: 89px;
-    }
-
     button {
         display: inline-block;
         width: 40%;