Added navbar.

Styles/Style.css

@@ -48,6 +48,13 @@ body {
     margin: 0;
     padding: 2rem;
 
+    display: grid;
+    grid-template-columns: minmax(0, 800px) auto;
+    justify-content: center;
+    align-items: start;
+    gap: 1rem;
+    min-height: 100vh;
+
     font-family: inherit;
     color: inherit;
 }
@@ -58,8 +65,12 @@ body {
 }
 
 .MainContainer {
+    grid-column: 1;
+    grid-row: 1;
+
+    width: 100%;
     max-width: 800px;
-    margin: 0 auto;
+    margin: 0;
     padding: 2rem;
 
     color: var(--Text);
@@ -182,3 +193,100 @@ input, button, textarea, select {
     font-family: inherit;
     color: inherit;
 }
+
+.Navbar {
+    grid-column: 2;
+    grid-row: 1;
+
+    display: flex;
+    flex-direction: column;
+    gap: 0.5rem;
+
+    padding: 0.5rem;
+
+    position: sticky;
+    top: 2rem;
+    align-self: start;
+
+    background-color: var(--Base);
+    border: 4px solid var(--Mauve);
+}
+
+.NavbarLink {
+    display: block;
+
+    width: 4rem;
+    height: 4rem;
+    padding: 0.4rem;
+
+    line-height: 0;
+    text-decoration: none;
+
+    background-color: var(--Mantle);
+    border: 3px solid var(--Surface2);
+    box-shadow: 3px 3px 0 var(--Crust);
+}
+
+.NavbarLink:hover {
+    background-color: var(--Surface0);
+    border-color: var(--Sky);
+
+    transform: translate(1px, 1px);
+    box-shadow: 2px 2px 0 var(--Crust);
+}
+
+.NavbarLink:focus-visible {
+    outline: 3px solid var(--Yellow);
+    outline-offset: 3px;
+}
+
+.NavbarLink[aria-current="page"] {
+    background-color: var(--Surface1);
+    border-color: var(--Mauve);
+}
+
+.NavbarLink[aria-current="page"]:hover {
+    background-color: var(--Surface2);
+    border-color: var(--Lavender);
+}
+
+.NavbarIcon {
+    display: block;
+
+    width: 100%;
+    height: 100%;
+
+    object-fit: contain;
+    image-rendering: pixelated;
+}
+
+@media (max-width: 700px) {
+    body {
+        grid-template-columns: minmax(0, 1fr);
+        gap: 1rem;
+        padding: 1rem;
+    }
+
+    .Navbar {
+        grid-column: 1;
+        grid-row: 1;
+
+        flex-direction: row;
+        width: 100%;
+
+        top: 0;
+        overflow-x: auto;
+        z-index: 1;
+    }
+
+    .NavbarLink {
+        flex: 0 0 3.5rem;
+        width: 3.5rem;
+        height: 3.5rem;
+    }
+
+    .MainContainer {
+        grid-column: 1;
+        grid-row: 2;
+    }
+}