This example shows a bar chart of server uptime in hours across five dates in January 2017, with hover highlighting on each bar. The visualization uses D3 v4 to bind the dataset, scales it from seconds to hours, and renders the bars as SVG rectangles with axes. It employs `d3.scaleBand` for the x-axis, `d3.scaleLinear` for the y-axis, and `d3.axisBottom`/`d3.axisLeft` for the ticks. The bars change color on mouseover via CSS, while the data comes from an embedded inline array rather than an external file.