Anyone else confused by the ending? Spoilers obviously

Um, did you watch the show?

Near knew Light was Kira. He deduced that Kira had to be working closely with the Japanese police when they got the notebook back from Mellow. Near then gets information from Mellow that there are fake rules in the notebook, he confronts the Japanese police with this information. Aizawa then contacts near and tells Near all about Light and Misa's incarceration along with Light's father's act to kill Light to stop the killings that L made him to.
This allowed Near to deduce the 2nd L as Light Yagami and since the original L suspected Light that is how he knew he was Kira.

Now fast forward to the end. Mellow had a contact with the SPK and she told him about Misa and Light. Mellow deduced that everything could be resolved with a single name written in the notebook. Mellow deduced that Takada was the one really killing the criminals not Mikami. Mellow had to get Mikami desperate enough to lure Mikami out to kill her with the real notebook. I doubt Mellow planned on dying though although he might have suspected it.

Anyway, the Giovanni had been following Mikami for weeks and knew his schedule which he never deviated from. So when Mikami goes to the bank for the 2nd time in a month, it raised their suspicions since Mikami only ever goes 1 time per month.
Mikami is the one who screwed up, and Light did not notice because Light wrote down Takada's name on his death note paper hidden in his watch which means Takada was already going to die before Mikami wrote down her name in the notebook at the bank.

So Giovanni took the original notebook and replaced it with a fake notebook knowing that Mikami was going to use that notebook to kill everyone at the Yellow Box warehouse on January 28.

So that is how Light got caught in the end and Light confessed when he told Near "Looks like I win" expecting him to die which sealed Light's fate.