HTML form , not responsive while inside a div - html

Question

I'm creating a web page and if i put my div inside a form it makes it non-responsive but if i put that same form outside the div, everything works just fine.
I wanted to have a div called container-2 and 2 forms inside, one is on the left as you can see and the other one is a card payment method. If i try to resize my screen, the second form goes under the first one because i've set the flex-wrap:wrap; but the first form stays non-responsive.
Here is the code and thanks in advance.
<div class="container-2">
<form method="POST">-
<div class="item" id="payment">
<div class="row">
<h4>Možnost nakupa 1: Plačilo po povzetju <small><i>(Za plačevanje s kartico je treba izbrati samo
količino in vrsto izdelka!)</i></small></h4>
{% csrf_token %}
{% if form %}
<div class="input-group">
<div style="color: red;">{{ form.name.errors }}</div>
{{ form.name }}
</div>
<div class="input-group">
<div style="color: red;">{{ form.last_name.errors }}</div>
{{ form.last_name }}
</div>
<div class="input-group">
<div style="color: red;">{{ form.street_name.errors }}</div>
{{ form.street_name }}
</div>
<div class="input-group">
<div style="color: red;">{{ form.city_name.errors }}</div>
{{ form.city_name }}
</div>
<div class="input-group">
<div style="color: red;">{{ form.email.errors }}</div>
{{ form.email }}
</div>
<div class="input-group">
<div style="color: red;">{{ form.number.errors }}</div>
{{ form.number }}
</div>
{% endif %}
</div>
</div>
<div class="item">
<div class="row">
<div class="input-group">
{{ form.num_elements.errors }}
{{ form.num_elements }}
</div>
<div class="input-group" id="check_div">
<div
style="display: flex;width:100%;justify-content: space-between;align-items: center;font-size:medium;flex-wrap: wrap;">
<div style="display: flex;justify-content: space-between;margin:3px;">
{{ form.select_type.errors }}
{{ form.select_type.label_tag }}
{{ form.select_type }}
</div>
<div style="display: flex;justify-content: space-between;margin:3px;">
{{ form.select_type2.errors }}
{{ form.select_type2.label_tag }}
{{ form.select_type2 }}
</div>
</div>
</div>
<div class="input-group">
{{ form.warning_el.errors }}
{{ form.warning_el }}
</div>
<div style="display: flex;justify-content: space-between;margin: 0.5rem;">
<button class="button" type="submit" id="button"> Naroči <small>(povzetje)</small></button>
<a class="button" id="stripe-button">Plačaj s kartico!</a>
</div>
</div>
</div>
</form>
<div>
<form id="payment-form" data-locale="si">
<div id="payment-element">
<!--Stripe.js injects the Payment Element-->
</div>
<button id="submit" class="button1">
<div class="spinner hidden" id="spinner"></div>
<span id="button-text">Pay now</span>
</button>
<div id="payment-message" class="hidden"></div>
</form>
</div>
</div>
This is container-2.

Answer 1

You can add 100% in with property of your form css:
#payment {
width: 100%;
}