Suppose $X$ and $Y$ are two Banach spaces and the embedding $ X \hookrightarrow Y $ is continuous. Does $ Y $ has the same zero element as $ X $? For me it seems trivial but I don't have the right arguement in hand. This question emerged from some contradiction arguement I was trying to prove that involved some $ u \in X$ such that $ \left\|u \right\|_X = 1 $ but $ \left\|u \right\|_Y = 0$ which would mean $ u = 0 $ in $Y$, hence $ \left\|u \right\|_X = 0 $ which is a contradiction. But I'm not sure how to justify that the zero element of $Y$ is the same as the zero element of $X$. We already know that since these are normed spaces, they are vector spaces. Is this enough and why? If $X$ was a subspace of $Y$ this is obvious but we do not know that.
Note: Our notion of a continuous embedding is as defined in this wikipedia article.
By wiki link you posed, Assuming $||x||_Y = 0 \iff x = 0_Y$ and $||x||_X = 0 \iff x = 0_X$, by continuous embedding definition you posted in Wiki link, $||0_X||_Y \leq C ||0_X||_X = 0 \implies ||0_X||_Y = 0 \implies 0_X = 0_Y$.