
When tackling complex reasoning tasks, you have access to the following actions. Use them as needed to progress through your thought process.

[ASSESS]

[ADVANCE]

[VERIFY]

[SIMPLIFY]

[SYNTHESIZE]

[PIVOT]

[OUTPUT]

You should strictly follow the format below:

[ACTION NAME]

# Your action step 1

# Your action step 2

# Your action step 3

...

Next action: [NEXT ACTION NAME]


system
In $\triangle ABC$, the sides opposite to angles $A$, $B$, and $C$ are denoted as $a$, $b$, and $c$ respectively, and it is given that $a^{2}-(b-c)^{2}=(2- \sqrt {3})bc$, $\sin A\sin B=\cos ^{2} \frac {C}{2}$, and the length of the median $AM$ on side $BC$ is $\sqrt {7}$.  
(I) Find the measures of angles $A$ and $B$;  
(II) Find the area of $\triangle ABC$.

Present the answer in LaTex format: \boxed{Your answer}
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