So I sloved it with a simple code. The thing is to make styles BEFORE js hubspot script builds the iframe. Here is the embed worked: <div class=“meetings-iframe-container” data-src=“https://meetings.hubspot.com/synder/intro-call-with-synder-team-integrations?embed=true”>
<iframe src=“https://meetings.hubspot.com/synder/intro-call-with-synder-team-integrations?embed=true” width=“100%” data-hs-ignore=“true” style=“min-width: 312px; min-height: 615px; height: 715px; border: none;”></iframe>
</div>
<script type=“text/javascript” src=“https://static.hsappstatic.net/MeetingsEmbed/ex/MeetingsEmbedCode.js”></script>