feat(theme): shiki styles + layouts

layouts/auto-grid.vue

@@ -1,24 +1,29 @@
 <script setup lang="ts">
-const props = defineProps<{
+defineProps<{
   columns?: number
+  rows?: string
 }>()
 </script>
 
 <template>
   <div class="slidev-layout">
-    <slot />
-    <div class="auto-grid">
-      <slot name="content" />
+    <div>
+      <slot />
+      <div class="auto-grid">
+        <slot name="content" />
+      </div>
+      <slot name="after" />
     </div>
   </div>
 </template>
 
 <style scoped>
 .auto-grid {
-  --_columns: v-bind(columns);
+  --columns: v-bind(columns);
+  --rows: v-bind(rows);
   display: grid;
-  grid-template-columns: repeat(var(--_columns, 2), 1fr);
-  grid-auto-rows: 250px;
+  grid-template-columns: repeat(var(--columns, 2), 1fr);
+  grid-auto-rows: var(--rows, auto);
   gap: var(--space-xs);
 }
 .auto-grid > * {