more nitpicks
Environment variables
=====================
-Here are the environment variables CuPy uses.
+For runtime
+-----------
+
+Here are the environment variables that CuPy uses at runtime.
.. envvar:: CUDA_PATH
@@ -100,7 +103,7 @@ Here are the environment variables CuPy uses.
Default: ``nvcc``
Define the compiler to use when compiling CUDA source.
- Note that most CuPy kernels are built with NVRTC; this environment is only effective for RawKernels/RawModules with ``nvcc`` backend or when using ``cub`` as the accelerator.
+ Note that most CuPy kernels are built with NVRTC; this environment variable is only effective for :class:`~cupy.RawKernels`/:class:`~cupy.RawModules` with ``nvcc`` backend or when using ``cub`` as the accelerator.
.. envvar:: CUPY_CUDA_PER_THREAD_DEFAULT_STREAM
