<div class="columns">
<div class="column is-narrow-desktop">
<div class="box" style="width: 200px;">
<p class="title is-5">Narrow column on desktop</p>
<p class="subtitle">This column is only 200px wide.</p>
</div>
</div>
<div class="column">
<div class="box">
<p class="title is-5">Flexible column</p>
<p class="subtitle">This column will take up the remaining space available.</p>
</div>
</div>
</div>