IIRC it was most powerfull single-engined fighter for years and like its predecessor Draken capable to operate from emergency bases using few hundred meters of public road as runway.
Viggen's empty weight was almost twice as much as F-16s and when armed for interception still 60-70% heavier than "Falcon" with similar load.
Definately not a lightweight fighter but AFAIK it could almost crash itself to the runway, refill and take off again so guess it was built like carrier fighters.