How to make responsive this section

i'm working on this website and i can't get out to these problems. As you can see on this pics i can't make responsive this gif with related text. On mobile it's always cutted, just like if the format is only for horizontal and not vertical page. How can i fix it? my next move if i can't fix it it's try to hidden this section for mobile and replace with another. Can be a good solution?

and this is the HTML:

<div class="main-banner" id="top">
    <video autoplay muted loop id="bg-video">
        <source src="assets/images/gym-video.mp4" type="video/mp4" width="100%" />
    </video>

    <div class="video-overlay header-text">
        <div class="caption">
            <h6></h6>
            <h2 style="font-size: 4vw">Senza motivazione non c'è <em>sacrificio</em>, senza sacrificio non c'è <em>disciplina</em>, senza disciplina non c'è <em>risultato</em>.</h2>
            <div class="main-button scroll-to-section">
                <a href="#features">Prenota la tua prova</a>
            </div>
        </div>
    </div>
</div>

and CSS

 .main-banner {
  position: relative;
}

#bg-video {
    width: 100%;
    height: auto;
    object-fit: cover;
    z-index: -1;
    overflow: hidden;
    padding-bottom: 56,25%;

}

#bg-video::-webkit-media-controls {
    display: none !important;
}

.video-overlay {
    position: absolute;
    background-color: rgba(35,45,57,0.8);
    top: 0;
    left: 0;
    bottom: 7px;
    width: 100%;
    padding-bottom: 56,25%
}

.main-banner .caption {
  text-align: center;
  position: absolute;
  width: 80%;
  left: 50%;
  top: 50%;
  transform: translate(-50%,-50%);
}

.main-banner .caption h6 
{
  margin-top: 0px;
  font-size: 22px;
  text-transform: uppercase;
  font-weight: 800;
  color: #fff;
  letter-spacing: 0.5px;
}

.main-banner .caption h2 {
  margin-top: 30px;
  margin-bottom: 25px;
  font-size: 57px;
  text-transform: uppercase;
  font-weight: 800;
  color: #fff;
  letter-spacing: 1px;
}

.main-banner .caption h2 em {
  font-style: normal;
  color: #ff0000;
  font-weight: 900;
}
 .main-banner .caption h2 strong {
   font-style: normal;
   color:black;
   font-weight:900;
 }

 /* For mobile phones: */
[class*="col-"] {
  width: 100%;
}

@media only screen and (min-width: 768px) {
  /* For desktop: */
  .col-1 {width: 8.33%;}
  .col-2 {width: 16.66%;}
  .col-3 {width: 25%;}
  .col-4 {width: 33.33%;}
  .col-5 {width: 41.66%;}
  .col-6 {width: 50%;}
  .col-7 {width: 58.33%;}
  .col-8 {width: 66.66%;}
  .col-9 {width: 75%;}
  .col-10 {width: 83.33%;}
  .col-11 {width: 91.66%;}
  .col-12 {width: 100%;}
}