The calendar design displayed here is a flexible and visually appealing option for organizing dates. The design features a flexbox layout, with the calendar elements aligned to the left side of the container.

Each date is represented by a date box, which has a margin and a background color to provide visual separation. The background lines add an interesting visual effect to the design. These lines are created using a pseudo-element, which is positioned relative to the container and covers the entire area. The lines are created using a repeating-linear-gradient, and help create a sense of depth and texture.

The date, month, and year labels are styled with a smaller font size, bold weight, and a gray color. These labels provide a clear indication of the date being displayed.

Overall, this flexible calendar design offers a visually appealing way to present dates. It can be easily incorporated into various web designs and provides a clean and organized look.