Great game, so close! It looks like white still has a chance right at the end, by playing A12 instead of N14 at move 219. If black blocks at A11, white can return to N14, and since white has slightly more ko threats white can win the ko on the left, which is enough to reverse the game.
At move 14, the hane at C5 is a common mistake. This is a joseki when black doesn’t already have the F3 stone, but with that stone black can cut and capture that hane like happened in the game. This is not a huge mistake, white is only a few points behind, but it comes up often so it’s worth to learn both white’s right move (just extend instead of hane) and the black punishment (like in the game).
After the result in that corner, the vital point at E5 was sente for both for many moves. You did get it in the end, but if black had played it first you would be forced to respond and then your shape is quite a bit worse. So play it as soon as possible!
Also, on a more complicated note, KataGo is suggesting a cool tesuji that I haven’t seen before in that corner:
Continuation hidden to not take up too much space with the images
After black hanes to separate, white can extend, making miai of capturing in a ladder or stealing away the corner:
To avoid giving white that opportunity, black should play hane connect instead of descending…
…aiming at this clamp, rather than the cut:
White is forced to connect, and black can bridge under:
This is the same as the normal joseki below, except that white made an unnecessary bad exchange!
So in the end, the white hane is still a mistake, but it’s quite a small mistake (at least when white has the ladder towards the upper right, like in this game).