Stairs design with two flights

Quick answer：

The phrase '楼梯设计两跑' refers to the design of stairs with two flights. In architectural design, a flight of stairs is a continuous run of steps between two landings or floors. Two flights of stairs would mean that there are two such runs in the stair design, possibly indicating a multi-level staircase or a complex design that features more than one staircase within the same structure.