如何使用bootstrap-vue在顶部设置标签标题粘滞

<template>
  <div>
    <b-navbar toggleable="lg" type="dark" variant="dark" fixed="top">
      <b-navbar-toggle target="nav-collapse"></b-navbar-toggle>
      <b-collapse id="nav-collapse" is-nav>
        <b-navbar-nav>
          <b-nav-item active>Home</b-nav-item>
          <b-nav-item>About</b-nav-item>
          <b-nav-item>Contact</b-nav-item>
        </b-navbar-nav>
      </b-collapse>
    </b-navbar>

    <!-- Your content goes here -->
  </div>
</template>

<script>
import { BNavbar, BNavbarToggle, BCollapse, BNavbarNav, BNavItem } from 'bootstrap-vue'

export default {
  components: {
    BNavbar,
    BNavbarToggle,
    BCollapse,
    BNavbarNav,
    BNavItem
  }
}
</script>