.assistant-sources was a grid with an auto column, which grows to its
widest unbreakable content — so a long file name such as
"2021_Fleisher_&_Ludwig's_Textbook_..." widened every card past the screen.
The column is now minmax(0,1fr), cards shrink (min-width:0) and names break
onto new lines (overflow-wrap:anywhere, with word-break for iOS < 15.4).
On phones the list is one vertical scroll: no sideways pan and no excerpt
scroll box inside it.
Measured on iPhone 14 / SE, Android 360 and Pixel: before, cards reached
636px on every phone (list overflowed by 236-288px); after, the widest card
ends 12px inside the screen and nothing scrolls sideways.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01W4rptBNvn6RYieQw54GXNS