🎨 (basic): Organiza estilos de Basic e Intro

Divide `basic.css` en parciales SCSS bajo `assets/scss/basic/`, integra
`normalize.css` en `basic.min.css` y compila `intro.scss` por separado a
`intro.min.css`.

assets/scss/basic/_table.scss

@@ -0,0 +1,51 @@
+.table-responsive {
+    overflow-x: auto;
+    -webkit-overflow-scrolling: touch;
+}
+
+.table {
+    width: 100%;
+    border-collapse: collapse;
+    text-align: left;
+}
+
+.table th,
+.table td {
+    padding: 0.5rem 0.75rem;
+    border-bottom: 1px solid color-mix(in srgb, var(--val-color--border) 15%, var(--val-color--bg));
+}
+
+.table thead th {
+    border-bottom-width: 2px;
+    font-weight: 600;
+}
+
+.table-sort {
+    color: inherit;
+    text-decoration: none;
+}
+.table-sort:hover {
+    text-decoration: underline;
+}
+.table-sort::after {
+    content: "\25BC";
+    margin-left: 0.25rem;
+    font-size: 0.8em;
+    opacity: 0.15;
+}
+.table-sort-asc::after {
+    content: "\25B2";
+    font-size: 0.8em;
+    opacity: 1;
+}
+.table-sort-desc::after {
+    content: "\25BC";
+    font-size: 0.8em;
+    opacity: 1;
+}
+
+.table-empty {
+    text-align: center;
+    font-style: italic;
+    color: var(--val-color--text--muted);
+}