Sticky table column

Try to scroll the main content of table horizontally to see the first column sticks to the left.
<th class="header">
<!-- Repeat other header column ... -->
.header {
/* Background color */
background-color: #ddd;
/* Stick to the left */
left: 0;
position: sticky;
/* Displayed on top of other rows when scrolling */
z-index: 9999;

See also

Sticky header

Sticky sections

Sticky table headers