Make session control fully ajax

public/src/assets/style.css

@@ -16,6 +16,44 @@ body {
   font-family: "WDXL Lubrifont JP N", sans-serif;
 }
 
+#message {
+  color: white;
+  position: absolute;
+  background-color: #1b262c;
+  width: calc(100vw - 10px);
+  padding: 5px;
+  display: block;
+  text-align: center;
+  font-size: 21px;
+  font-family: "WDXL Lubrifont JP N", sans-serif;
+  opacity: 1;
+  transition: opacity 0.5s ease-in-out;
+}
+
+#message.hide {
+  opacity: 0;
+}
+
+#message::after {
+  content: "X";
+  color: white;
+  position: absolute;
+  right: 10px;
+  cursor: pointer;
+}
+
+#message:hover::after {
+  color: #90bdd9;
+}
+
+#message:empty {
+  display: none;
+}
+
+#message:empty:after {
+  display: none;
+}
+
 button {
   font-family: "WDXL Lubrifont JP N", sans-serif;
   font-size: 18px;
@@ -132,7 +170,7 @@ input {
 }
 
 .form button {
-  margin-top: 20px;
+  margin-top: 10px;
   padding: 10px;
   background-color: #3498db;
   color: white;
@@ -152,6 +190,9 @@ input {
 
 .header-right {
   margin-right: 20px;
+  display: flex;
+  white-space: nowrap;
+  gap: 10px;
 }
 
 .account-button {
@@ -160,7 +201,6 @@ input {
   cursor: pointer;
   color: #90bdd9;
   font-size: 23px;
-  margin-right: 10px;
   font-family: "WDXL Lubrifont JP N", sans-serif;
 }