Css code that seems to optimize, - css

Question

I was curious to what this code does. I found it on a site, and I am wondering if it has anything to with device optimization. It seems to effect the whole page through all devices. Especially the part that says "#media screen and (min-width:992px)".
<style>
html {
-webkit-font-smoothing: antialiased;
}
.w-container {
max-width: 100%;
}
.w-container .w-row {
margin-left: 0;
margin-right: 0;
}
.w-row {
margin-left: 0;
margin-right: 0;
}
.w-row .w-row {
margin-left: 0;
margin-right: 0;
}
.w-col .w-col, .w-col {
padding-left: 0;
padding-right: 0;
}
.pad-row .w-col {
padding-left: 10px;
padding-right: 10px;
}
.pad-row.w-row, .pad-row .w-row {
margin-left: -10px;
margin-right: -10px;
}
/*---------------------------------*/
.slider-outer {
display: table;
width:100%;
height: 100%;
}
.slider-left, .slider-right {
display: table-cell;
width:50%;
height:100%;
vertical-align: middle;
}
.slider-left {
text-align: right;
}
.slider-right {
text-align: left;
}
/*---------------------------------*/
.w-slider-nav-invert>div {
border: white 3px solid;
background: black;
}
.w-slider-nav-invert>div.w-active {
border: white 3px solid;
background: white;
}
.w-slider-dot {
width: 1em;
height: 1em;
}
/*---------------------------------*/
.table {
display:table;
width: 100%;
}
.t-row {
display:table-row;
}
.t-cell {
display:block;
vertical-align: top;
}
#media screen and (min-width:992px) {
.t-cell {
display:table-cell;
vertical-align: top;
}
}
</style>
I know that this is css, but it seems like clever code to make the page optimizable through all devices. It is in an html embed on this site https://preview.webflow.com/preview/uniqlo-responsive?preview=aacb16f7eb6a5df89780c3f5bbee094d. You can go in there and double click on an html embed, and the code will be there.

Answer 1

What you're looking at is known as a media query.
The min-width: 992px you see denotes that the CSS inside of it will only trigger of viewports that are at least 992px wide (which is the equivalent of a laptop). You can think of media queries as 'conditional CSS logic' to control how a website looks on different devices.
Note that the media queries pertain to the browser width / height, not the screen width / height. As such, manually resizing your browser window will trigger media query breakpoints.
In this specific case, .t-cell { display: table-cell; vertical-align: top; } is applied when the viewport is at least 992px wide. This will make the content display in a tabular format on larger devices, while the content retains display: block for mobile devices (allowing it to stack).