I have problem with resizing web screen and div elements on it - html

Question

This is on a normal window size:
And this is how it looks like when I resize window
I want to move these 2 elements from bottom to up smoothly when someone resizes the web screen. I even tried to add here an extra element between up elements and down elements, but it still doesn't work.
I know that I can use #medi" elements, but it doesn't make it move smoothly. Is there any other way to do this?
.nav-bar {
background-color: #e4e8ea;
position: fixed;
display: flex;
flex-direction: column;
justify-content: space-between;
margin-top: -20px;
width: 75px;
height: 840px;
z-index: 101;
}
.nav-bar-top {
height: 380px;
}
.nav-bar-top-button {
height: 90px;
display: flex;
justify-content: center;
align-items: center;
flex-direction: column;
cursor: pointer;
}
.nav-bar-top-button div {
font-family: Multiround Pro;
}
.pop {
font-size: 13px;
}
.fav {
font-size: 11px;
}
.recently {
font-size: 13px;
}
.home-button {
background: url('/Images/home-page.png') no-repeat;
background-size: 28px;
background-position: 35px 20px;
padding-top: 60px;
font-size: 15px;
padding-left: 27px;
transition: background 0.5s;
height: 90px;
width: 75px;
}
.pop-button {
background: url('/Images/popular-button.png') no-repeat;
background-size: 28px;
background-position: 27px 20px;
padding-top: 60px;
font-size: 15px;
padding-left: 9px;
transition: background 0.5s;
height: 90px;
width: 75px;
}
.fav-button {
background: url('/Images/favourite-1.png') no-repeat;
background-size: 28px;
background-position: 24px 20px;
padding-top: 60px;
font-size: 15px;
padding-left: 3px;
transition: background 0.5s;
height: 90px;
width: 75px;
}
.recently-viewed-button {
background: url('/Images/recently-viewed-1.png') no-repeat;
background-size: 28px;
background-position: 24px 13px;
padding-top: 51px;
font-size: 15px;
transition: background 0.5s;
height: 90px;
width: 75px;
text-align: center;
}
.nav-bar-middle {
flex: 1;
max-height: 10px;
display: flex;
align-items: center;
}
.nav-bar-bottom {
height: 200px;
width: 75px;
overflow: hidden;
display: flex;
flex-direction: column;
align-items: center;
}
.nav-bar-bottom-button {
height: 90px;
width: 75px;
cursor: pointer;
}
.nav-bar-bottom div {
font-family: Multiround Pro;
}
.support-button {
font-size: 14px;
}
.support-button,
.setting-button {
padding-top: 40px;
}
.support-button {
background: url('/Images/support-1.png') no-repeat;
background-size: 28px;
background-position: 24px 20px;
padding: 60px 0px 0px 4px;
transition: background 0.5s;
height: 90px;
width: 75px;
}
.setting-button {
background: url('/Images/settings.png') no-repeat;
background-size: 28px;
background-position: 24px 20px;
padding: 60px 0px 0px 4px;
transition: background 0.5s;
height: 90px;
width: 75px;
}
<nav class="nav-bar">
<div class="nav-bar-top">
<div class="nav-bar-top-button">
<div class="home-button" title="Home">
<div>Home</div>
</div>
</div>
<div class="nav-bar-top-button">
<div class="pop-button">
<div class="pop">Popular</div>
</div>
</div>
<div class="nav-bar-top-button">
<div class="fav-button">
<div class="fav">Favourites</div>
</div>
</div>
<div class="nav-bar-top-button">
<div class="recently-viewed-button">
<div class="recently">Recently viewed</div>
</div>
</div>
</div>
<div class="nav-bar-middle">
<div></div>
</div>
<div class="nav-bar-bottom">
<div class="nav-bar-bottom-button">
<div class="support-button">Support</div>
</div>
<div class="nav-bar-bottom-button">
<div class="setting-button">Setting</div>
</div>
</div>
</nav>