When Markdowning the post, it doesn't goes downfall

I mean, I have a post with a youtube video embedded, and some text, but it goes to the right, instead of down.

I want it to go down…

My HTML code is:

<div class="container">
  <div class="row">
    <nav class="col-sm-3 ">
      <div class="col-sm-12" id="fixed-sidebar">
        <!-- <a href="index.html"><img id="home-logo" src="../../media/logo-prueba.jpg" alt="Logo de Animanoir"> </a> -->
          <li class="fuente-fjalla ul-personalizada">Animación</li>
          <li class="fuente-fjalla ul-personalizada">Ilustración</li>
          <li class="fuente-fjalla ul-personalizada">Interacción</li>
          <li class="fuente-fjalla ul-personalizada">Blog</li>
          <li class="fuente-fjalla ul-personalizada">Acerca</li>
          <li class="fuente-fjalla ul-personalizada">Contacto</li>

    <div class="col-sm-9" id="main-content">

      <div class="row">

        <h2>{{ post.title }}</h2>




‘post’ layout:

<!DOCTYPE html>
<html lang="es">

{%include head.html%}

    <!-- Imagen header que dice Animanoir -->
    {%include header.html%}

    <!-- El sidebar y el contenido  -->
    {%include sidebar-main-post.html%}

    <!-- Footer normal -->
    {%include footer.html%}

    <!-- El jQuery de Bootstrap 4.0.0beta -->
    {%include js.html%}

    {%include hogarjq.html%}


‘main-content’ CSS:

#main-content {
    color: white;
    font-family: 'Average', serif;
    font-size: 1em;

You may try the clear: both; css property and value for whatever HTML object you’re using to embed the youtube video.

Does that work?

Well, what worked was having a lone paragraph above it. That’s how MD works?