<h2>{global:formtitle}</h2>
{error}
<!-- Do not remove this ID, it is used to identify the page so that the pagination script can work correctly -->
To make the YouTube video responsive with a 100% width variable while maintaining its aspect ratio, you can use a responsive container. Here's the correct code:

<div style="position: relative; padding-bottom: 56.25%; height: 0; overflow: hidden; max-width: 100%; margin: 0 auto;">
    <iframe src="https://www.youtube.com/embed/55LdjJpdV9Y?si=52mnyNrXcZc0_Wol" 
            title="YouTube video player" 
            frameborder="0" 
            allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" 
            referrerpolicy="strict-origin-when-cross-origin" 
            allowfullscreen
            style="position: absolute; top: 0; left: 0; width: 100%; height: 100%;">
    </iframe>
</div><fieldset class="formContainer" id="rsform_{global:formid}_page_0">
	<div class="row">
		<div class="col-md-12">
			<div class="mb-3 rsform-block rsform-block-select-which-best-describes-you rsform-type-radiogroup{Select_which_best_describes_you:errorClass}">
{if {Select_which_best_describes_you:caption}}
				<label class="form-label formControlLabel" data-bs-toggle="tooltip" title="{Select_which_best_describes_you:descriptionhtml}" id="Select_which_best_describes_you-grouplbl">{Select_which_best_describes_you:caption}<strong class="formRequired">(*)</strong></label>
{/if}
				<div class="formControls" role="group" aria-labelledby="Select_which_best_describes_you-grouplbl">
					{Select_which_best_describes_you:body}
					<div><span class="formValidation">{Select_which_best_describes_you:validation}</span></div>
				</div>
			</div>
			<div class="mb-3 rsform-block rsform-block-name rsform-type-textbox{Name:errorClass}">
{if {Name:caption}}
				<label class="form-label formControlLabel" data-bs-toggle="tooltip" title="{Name:descriptionhtml}" for="Name">{Name:caption}<strong class="formRequired">(*)</strong></label>
{/if}
				<div class="formControls">
					{Name:body}
					<div><span class="formValidation">{Name:validation}</span></div>
				</div>
			</div>
			<div class="mb-3 rsform-block rsform-block-email rsform-type-textbox{Email:errorClass}">
{if {Email:caption}}
				<label class="form-label formControlLabel" data-bs-toggle="tooltip" title="{Email:descriptionhtml}" for="Email">{Email:caption}<strong class="formRequired">(*)</strong></label>
{/if}
				<div class="formControls">
					{Email:body}
					<div><span class="formValidation">{Email:validation}</span></div>
				</div>
			</div>
			<div class="mb-3 rsform-block rsform-block-phone rsform-type-textbox{Phone:errorClass}">
{if {Phone:caption}}
				<label class="form-label formControlLabel" data-bs-toggle="tooltip" title="{Phone:descriptionhtml}" for="Phone">{Phone:caption}</label>
{/if}
				<div class="formControls">
					{Phone:body}
					<div><span class="formValidation">{Phone:validation}</span></div>
				</div>
			</div>
			<div class="mb-3 rsform-block rsform-block-city-town-or-region rsform-type-textbox{City_Town_or_Region:errorClass}">
{if {City_Town_or_Region:caption}}
				<label class="form-label formControlLabel" data-bs-toggle="tooltip" title="{City_Town_or_Region:descriptionhtml}" for="City_Town_or_Region">{City_Town_or_Region:caption}</label>
{/if}
				<div class="formControls">
					{City_Town_or_Region:body}
					<div><span class="formValidation">{City_Town_or_Region:validation}</span></div>
				</div>
			</div>
			<div class="mb-3 rsform-block rsform-block-submit rsform-type-submitbutton{Submit:errorClass}">
{if {Submit:caption}}
				<label class="form-label formControlLabel" data-bs-toggle="tooltip" title="{Submit:descriptionhtml}">{Submit:caption}</label>
{/if}
				<div class="formControls">
					{Submit:body}
					<div><span class="formValidation">{Submit:validation}</span></div>
				</div>
			</div>
		</div>
	</div>
</fieldset>