a 40 mins game @.@ means the result will not come down to 1 major mistake. both player must had traded mistakes lol. anyway i would like to point out a few things.

1st, you opened gas first, your opponent rax first, his factory only started when yours is about half way done. yet his banshee reach earlier than you by a f***load of time. and both of  you finish cloak at same time. gas first cloak rush is supposed to be much faster, means your build order got fatal mistake if its in higher league. gas first will sacrifice alot of economy. see when his banshee reach your base, he had alot more scv than you (24 to 20 i think and 6 on gas which means alot cuz 18 scv vs 12scv is 50% more mineral) but then your banshee management is far better than his. his banshee dealt little dmg, yours dealt alot. so it kinda evened up already.

2nd, after the banshee thing and both kinda settle down in 2 base. both of you have 1 factory constant siege tank production but he have 4 tanks when you have 2. if he had attacked at that moment, you are in big trouble. why he have 4? because his macro is better than you, you need to fix this. dont supply block yourself. a good indicator is when you block at 62/62 supply, he had 74/78 and is shooting up further to 80+ but you are still waiting for your depot to finish.

3rd, when you do your doom drop, notice you are already very far behind initially. he was at 177 supply and you just passed 150 i think. but you did more dmg than you expected and supply blocked him. so you kinda caught up in supply by abit by then. its also worth to notice that you had not make any viking production before this point. only 1 viking.

4th, all the while, your scv count is very low. you did not make constant scv production after about 15 min~ so even you had 10+ scv kill in your banshee opening, he caught up very fast in scv count. and you were about 10 scv less than him all the time. (which means  he outproduce 20 scv from you in the course of 10 in game minute something worth noting) less scv = less income = less supply. get?

5th, the tank marine movement in the middle. i paused and checked. he had 15 tanks, you have 12. he had 2-2 you have 1-1, he have 9 vikings you have 5. but you have 45 rines, he have 30+.....and unfortunately marine count is the least important in this 4. his 3-3 is also 20% done by that time. and he was constantly producing army and you are not. (macro problem)

6th, your sudden mass viking is a good move. suddenly you have like 10 viking he have only 1-2, and you use your high gorund advantage and viking advantage to slow push. beccause of that you had overtake him in supply. but thats partially due to his BC transition. when you see the BC, you should make more vikings and not sacing them to the ground 3-3 marines of his. big engagemnt mistake there.

7th, you had 4 reactored starport, you could have constantly make 8 vikings at a time and outproduce your opponent but you didnt.  well, you have like 11 marines left to hit air and near to 0 vikings. at this time, you should back off your tanks and wait for a few rounds of vikings. keep them!! not make 8, then die to his 20 vikings, then make 8 more then die again. queue up your viking productions dont waste 5 sec in between and dont waste them to your enemy, keep them in your base, wait till you have more and attack back. you surely will outproduce your opponent. you had 1k mineral 500 gas floating most of the time, use them on vikigns!

basically at stage 1,2 you were massively behind of your opponent (early game)

stage 2,3,4,5 you used your marine tank management to win important engagements and it brought you ahead. if you continue to push in, you will win. but you need to make more army! dont stop making them cuz they are good. (mid game skirmish)

stage  6,7 his sky terran transition totally owned you but that might be caused of your inexperience to deal with it. when his viking count is too big, you are on your macro death bed already. its just a matter of time till you lose, even the drastic base trade wouldnt change much as you can see. how to deal with it? tanks become not important anymore other than to hold his marines back from firing your vikings. if you need to, drop or sac tanks to his expo to free up supply for your vikings. you need more vikings and have a larger death ball. thats about it. (late game)