I'm trying to overlapping one div to another div using z-index property
This is my html code snippet:
<div class="container-fluid">
    <div class="one">
    </div>
    <div class="two">
    </div>
</div>
This is my css code snippet:
.container-fluid{
    max-width: 650px;
    width: 95%;
    padding: 30px;
    background-color: rgb(250, 252, 253);
    border-radius: 4px;
    border: 1px solid #dfe1e5;
    position: relative;
}
.one{
    height: 400px;
    border: 2px dashed #8b8e96;
    background-color: #fffce5;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-direction: column;
    position: relative;
    margin: 10px auto;
    z-index: 1;
}
.two{
    height: 400px;
    border: 2px dashed #8b8e96;
    background-color: #fffce5;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-direction: column;
    margin: 10px auto;
    position: relative;
    z-index: 2;
    top: 10px;
}
I want to overlap class two div on class one div, but when I apply this attributes the class two div not overlapping on class one div . It's display like block element. Can anyone please tell me why it's happening and how can fix this issue?
 
     
    