Add nice looks to the sidebar

src/components/navigation/Sidebar.astro

···
 ---
 
 <aside id="sidebar" popover>
+  <h2>Navigation</h2>
+
   <nav>
     {
       (() => {
···
     top: 0;
     right: 0;
     height: 100%;
+
+    background-color: white;
+    color: black;
+    border: 5px solid black;
+    border-radius: 20px 0 0 20px;
+    box-shadow: 0 10px;
+    padding: 10px 20px;
+
+    & ul {
+      padding-inline: 1em;
+    }
+
+    &::backdrop {
+      background-color: #00000040;
+      backdrop-filter: blur(5px);
+    }
   }
 </style>