Page Problem

I just get some code for a page with 'Collapsibles' .

The problem is

Once I input the code to the page, feels like the page dismisses from the the admin cpanel, but I still can click ' Preview', ' Clone', ' Delete'

And I check the page in front store, it works well.

Check the code below, and find my screenshort from the attachments.

You can use the code for a test in the localhost.

Let me know if anything wrong I made.

.collapsible {
background-color: #777;
color: white;
cursor: pointer;
padding: 18px;
width: 100%;
border: none;
text-align: left;
outline: none;
font-size: 15px;
}
.active, .collapsible:hover {
background-color: #555;
}
.content {
padding: 0 18px;
display: none;
overflow: hidden;
background-color: #f1f1f1;
}

Collapsibles

A Collapsible:

Open Collapsible

Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.

Collapsible Set:

Open Section 1

Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.

Open Section 2

Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.

Open Section 3

Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.

Second code, html with css, works great.

body {
font-family: Arial, Helvetica, sans-serif;
}
.flip-box {
background-color: transparent;
width: 300px;
height: 200px;
border: 1px solid #f1f1f1;
perspective: 1000px;
}
.flip-box-inner {
position: relative;
width: 100%;
height: 100%;
text-align: center;
transition: transform 0.8s;
transform-style: preserve-3d;
}
.flip-box:hover .flip-box-inner {
transform: rotateY(180deg);
}
.flip-box-front, .flip-box-back {
position: absolute;
width: 100%;
height: 100%;
-webkit-backface-visibility: hidden;
backface-visibility: hidden;
}
.flip-box-front {
background-color: #bbb;
color: black;
}
.flip-box-back {
background-color: dodgerblue;
color: white;
transform: rotateY(180deg);
}

3D Flip Box (Horizontal)

Hover over the box below:

Front Side

Back Side

admiN.jpg

admin-2.jpg

front.jpg

I you want to integrate this 3rd party code to CS-Cart, hire someone to perform this work for you

I you want to integrate this 3rd party code to CS-Cart, hire someone to perform this work for you

I wonder if possible you can check what the problem is from the first code?