It is not natural for more complex things to arise from less complex.
There are innumerable instances of this being the case - weather patterns, movements of schools of fish, evolution by natural selection, creation of river deltas by the combination of sedimentation and tidal erosion...
If nothing else, 'nature' appears to be the interaction of five fundamental forces, and yet here you are as a manifestation of those forces deploying 26 letters and a few punctuations marks through a created coding system to convey meaning via a collective electronic reference system around the world whilst still being manifestly, demonstrably, almost painfully wrong.
It is demonstrable that naturally occurring events tend to destroy complexity rather than create it.
Tend to, but not exclusively do. Given enough time. And a closed system.
It is why all living things will eventually die.
It's actually not, but it is why we have a probably heat-death of the universe to look forward to.
It was a miracle that the first living cell was not killed off by natural forces before it reproduced.
We don't know that the first wasn't, and who knows how many others that followed also died off quickly - we only have evidence that one (at least) survived long enough to establish a self-replicating chain that, subject to evolutionary developments, continues to this day.
The ability of living things to reproduce is evidence of intentional design to combat the natural events which ultimately destroy life and generate ever increasing chaos.
It's neither evidence for nor against an intentional design, in and of itself, it's simply evidence of a system that requires reproduction in order to continue. The same fragility of data-units and replication that leads to individual organisms dying is part of the mechanism that leads to variation between generations even in asexual reproduction - to try to divide one into motivation and another into technique in the eye of some overseeing designer is to fail to appreciate that they are facets of the same function.
O.