fix: mount custom.css to assets directory, not css

static_paths only includes: assets, fonts, images, js
The css directory is NOT served by Phoenix.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

asciinema/Dockerfile

@@ -0,0 +1,26 @@
+FROM ghcr.io/asciinema/asciinema-server:latest AS base
+
+# Download the source to find and patch the template
+FROM elixir:1.18-alpine AS builder
+
+# Install git and build dependencies
+RUN apk add --no-cache git build-base nodejs npm
+
+# Clone the asciinema-server repository
+WORKDIR /app
+RUN git clone https://github.com/asciinema/asciinema-server.git .
+RUN git checkout v1.0.0
+
+# Patch the layout template to inject custom theme
+RUN sed -i '/<\/head>/i\    <!-- Custom Pivoine Rose Theme -->\n    <link rel="stylesheet" href="/theme/custom.css" />\n    <link rel="icon" type="image/svg+xml" href="/theme/favicon.svg" />' \
+    lib/asciinema_web/templates/layout/app.html.heex
+
+# Build the release
+RUN mix local.hex --force && \
+    mix local.rebar --force && \
+    mix deps.get --only prod && \
+    MIX_ENV=prod mix do compile, assets.deploy, release
+
+# Final image: copy the patched release over the base image
+FROM base
+COPY --from=builder /app/_build/prod/rel/asciinema /opt/app/