Niners score on all three first-half drives, take 13-10 halftime lead

Led by a sharp offense, the 49ers took a 13-10 lead after two quarters vs. visiting Kansas City on Sunday. Quarterback Colin Kaepernick connected on 8-of-15 passes for 122 yards in the first half, and his nine-yard scoring toss to a wide-open Stevie Johnson with about 30 seconds left in the second quarter put San…