Disconnect the battery and do a full inspection of the logic board (take it out) following this IFIXIT guide: [guide|12347|MacBook Air 11" Mid 2012 Logic Board Replacement]. Once your sure the logic board did not get wet or if it did you've been able to clean off the spillage fully and no components look burnt see if you can get it to work with the battery disconnected and only having the MageSafe adapter plugged in. Is it able to come up at all? If not you likely need a new logic board and battery.
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Disconnect the battery and do a full inspection of the logic board (take it out) following this IFIXIT guide: [guide|12347|MacBook Air 11" Mid 2012 Logic Board Replacement].
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Once your sure the logic board did not get wet or if it did you've been able to clean off the spillage fully using 85% or better isopropyl alcohol and a soft toothbrush and check to make sure no components look burnt.
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See if you can get it to work with the battery disconnected and only having the MageSafe adapter plugged in. Is it able to come up at all? If not you likely need a new logic board and battery.
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The MagSafe adapter should be bright Amber in this condition. If not you know the charging logic is damaged.
Disconnect the battery and do a full inspection of the logic board (take it out) following this IFIXIT guide: [guide|12347|MacBook Air 11" Mid 2012 Logic Board Replacement]. Once your sure the logic board did not get wet or if it did you've been able to clean off the spillage fully and no components look burnt see if you can get it to work with the battery disconnected and only having the MageSafe adapter plugged in. Is it able to come up at all? If not you likely need a new logic board and battery.