  We measure the branching fractions and $CP$ asymmetries for the decays
$B^{0}\to \bar{D}^{0}\pi^{0}$ and $B^{+}\to \bar{D}^{0}\pi^{+}$, using a data
sample of $772\times 10^{6}$ $B\bar{B}$ pairs collected at the $\Upsilon(4S)$
resonance with the Belle detector at the KEKB $e^{+}e^{-}$ collider. The
branching fractions obtained and direct $CP$ asymmetries are
$\mathcal{B}(B^{0}\to \bar{D}^{0}\pi^{0}) = [2.70 \pm 0.06~ \text{(stat.)} \pm
0.10~ \text{(syst.)}] \times 10^{-4}$, $\mathcal{B}(B^{+}\to
\bar{D}^{0}\pi^{+}) = [4.53 \pm 0.02~ \text{(stat.)} \pm 0.15~ \text{(syst.)}]
\times 10^{-3}$, $ {\cal A}_{CP}(B^{0}\to \bar{D}^{0}\pi^{0}) = [+0.42 \pm
2.05~ \text{(stat.)} \pm 1.22~ \text{(syst.)}]\%$, and $ {\cal A}_{CP}(B^{+}\to
\bar{D}^{0}\pi^{+}) = [+0.19 \pm 0.36~ \text{(stat.)} \pm 0.57~
\text{(syst.)}]\%$. The measurements of $\mathcal{B}$ are the most precise to
date and are in good agreement with previous results, as is the measurement of
${\cal A}_{CP}(B^{+}\to \bar{D}^{0}\pi^{+})$. The measurement of ${\cal
A}_{CP}$ for $B^{0}\to \bar{D}^{0}\pi^{0}$ is the first for this mode, and the
value is consistent with Standard Model expectations.
