The first simple example makes use of the Bootstrap 4 CSS classes d-flex and flow-row: d-flex flex-row my-flex-container">. Platform D South arrives at NASA's Kennedy Space Center in Florida. Liquid Hydrogen Tanker Flex Hose Fit Check at Launch Pad 39B. Educational Launch of Nanosatellites, NASA Kennedy Space Center . I'd like to extend my deepest appreciation to the primary missions. Ye Zhang, Ph.D., NASA Kennedy Space Center, Cape Canaveral, FL, United States . The subassembly is reinstalled to the flex arms attached to the Veggie. I'm an inline flexbox container!. Responsive variations also exist for.d-flex and.d-inline-flex..d-flex.d-inline-flex.d-sm-flex. However, no new features will be added to it. To create a flexbox container and to transform direct children into flex items, use the d-flex class.