STEM homepage font comparison and self-hosted assets

All four font files are unmodified copies from the official Google Fonts
repository, pinned to revision e7db6ca603fd4862010383ff17ffd6cc4ffac1c0.
Each font is distributed under the SIL Open Font License, Version 1.1.
The original license and Google Fonts metadata are included in each folder.
SOURCES.json records the exact download URLs, byte lengths and SHA-256 hashes.

Anton: Copyright 2020 The Anton Project Authors
Big Shoulders Display: Copyright 2019 The Big Shoulders Project Authors
League Gothic: Copyright 2010 The League Gothic Project Authors
IBM Plex Mono: Copyright © 2017 IBM Corp. with Reserved Font Name "Plex"
See each OFL.txt for the complete authoritative copyright/license notice.

The hero uses Anton at its native Regular (400) weight. Its outlines are
already heavy; no synthetic bold or artificial horizontal stretching is needed.
The comparison uses Big Shoulders Display at Black (900), League Gothic at
its default width (100), and IBM Plex Mono Regular (400) for small captions.
Only these four font binaries are included; no italic or additional static
weight files are downloaded.

Anton is the initial recommendation for the written ultra-condensed, heavy
grotesque brief. The named IMG_7922 reference was not supplied; exact visual
matching to that image is unverified. fonts-stem.html provides the three SVG
specimens for browser inspection, with identical words and no copied artwork.

This page loads fonts from the current origin. It makes no Google Fonts CSS
or font-service requests at runtime.