div(
  br(),
  helpText(
    style = "font-size: 11px;",
    "Use your mouse to highlight areas in the traceplot to zoom into. Double-click to reset.",
    "You can also use the range selector below the graph for panning and zooming.",
    "The number in the small black box in the bottom left corner controls the",
    em("roll period."),
    "If you specify a roll period of N the resulting graph will be a moving average,",
    "with each plotted point representing the average of N points in the data."
  )
)
