(“Its” is hard to use as a possessive pronoun. It’s often better to use the possessive adjective instead.)
Subject
Possessive Adjective
Possessive Pronoun
we
our
ours
This is our website.
This website is ours.
Subject
Possessive Adjective
Possessive Pronoun
you
your
yours
Those uniforms of yours look great.
Subject
Possessive Adjective
Possessive Pronoun
they
their
theirs
My dog is brown.
Theirs are gold.
Note: it’s also possible to say, “Theirs is gold,” if they have just one dog. A possessive pronoun is singular or plural depending on the antecent. An “antecedent” is the word or words to which the pronoun refers.