Indeterminate demo added

doc/checkbox/IndeterminateDoc.vue

@@ -0,0 +1,54 @@
+<template>
+    <DocSectionText v-bind="$attrs">
+        <p>When <i>indeterminate</i> is present, the checkbox state specified as indeterminate.</p>
+    </DocSectionText>
+    <div class="card flex justify-content-center">
+        <Checkbox v-model="checked" indeterminate binary />
+    </div>
+    <DocSectionCode :code="code" />
+</template>
+
+<script>
+export default {
+    data() {
+        return {
+            checked: false,
+            code: {
+                basic: `
+<Checkbox v-model="checked" indeterminate binary />
+`,
+                options: `
+<template>
+    <div class="card flex justify-content-center">
+        <Checkbox v-model="checked" indeterminate binary />
+    </div>
+</template>
+
+<script>
+export default {
+    data() {
+        return {
+            checked: false
+        };
+    }
+};
+<\/script>
+`,
+                composition: `
+<template>
+    <div class="card flex justify-content-center">
+        <Checkbox v-model="checked" indeterminate binary />
+    </div>
+</template>
+
+<script setup>
+import { ref } from "vue";
+
+const checked = ref(false);
+<\/script>
+`
+            }
+        };
+    }
+};
+</script>

pages/checkbox/index.vue

@@ -18,6 +18,7 @@ import DynamicDoc from '@/doc/checkbox/DynamicDoc.vue';
 import FilledDoc from '@/doc/checkbox/FilledDoc.vue';
 import GroupDoc from '@/doc/checkbox/GroupDoc.vue';
 import ImportDoc from '@/doc/checkbox/ImportDoc.vue';
+import IndeterminateDoc from '@/doc/checkbox/IndeterminateDoc.vue';
 import InvalidDoc from '@/doc/checkbox/InvalidDoc.vue';
 import PTComponent from '@/doc/checkbox/pt/index.vue';
 import ThemingDoc from '@/doc/checkbox/theming/index.vue';
@@ -36,6 +37,11 @@ export default {
                     label: 'Basic',
                     component: BasicDoc
                 },
+                {
+                    id: 'indeterminate',
+                    label: 'Indeterminate',
+                    component: IndeterminateDoc
+                },
                 {
                     id: 'group',
                     label: 'Group',