The weather widget's icons/layout are hand-drawn PIL primitives -- clean under quantization but flat, no gradients/shadows. Adds an opt-in render_style="modern" (current/daily modes only) that instead renders a Jinja2 template through a persistent headless-Chromium browser (app/html_render.py), following the approach of Tesserae, an open-source e-ink dashboard targeting this same panel family. Key design points: - The Chromium dependency (Playwright) is lazily imported only when a weather widget actually uses "modern" style, and the background browser itself only launches on first use -- every other widget type, and this one's own classic/hourly/multi_city paths, never pay for it. - No Frame-level dithering setting needed: html_render dithers its own rendered widget to exact palette colors (Bayer/ordered, not Floyd-Steinberg) before compositing, so the shared whole-canvas Floyd-Steinberg pass sees zero quantization error there and leaves it untouched -- same trick draw_text/hand-drawn icons already use. Floyd- Steinberg keeps working unchanged for photos and every other widget. - A "Load calibrated Spectra 6 preset" button in Advanced configuration offers a community-measured palette (data ported from paperlesspaper/epdoptimize, Apache 2.0) as an alternative starting point to the existing idealized DEFAULT_PALETTE_RGB -- fills the existing palette table, doesn't save by itself. Known open risk, not resolved here: a headless Chromium binary is far larger than the ~100MB single-layer limit that already forced this project's pip/npm installs into split layers, and (unlike those) is a single ~180MB file that can't be split across layers by ordinary Dockerfile restructuring. Flagged prominently in server/Dockerfile and docs/widgets.md -- treat this render style as experimental/local-only until that's resolved.