Clearly, Seulong's hairstyle looks like another ordinary short haircut, but look closely. You see it is nicely trimmed up so that it's actually weighing on the heavy, thick side.
His fringes and sides are actually folding downward toward his skin. That means it's relatively thick. This kind of haircut is hard to maintain especially one would have to get it trimmed up precisely, not to make it look too bushy.
Notice how Seulong's face shape is falling onto the triangle shaped category. Seulong is doing rather a great job of balancing out his facial features, especially his face shape.
Clearly, this IS Seulong's signature haircut! From looking at his relatively "unique" hairstyle this is the concluding review:8/10 for his trendy style
6/10 for the maintainability of his haircut
9/10 for the short length of his haircut according to his face shape