// Attribute structure
{
  key: String,  // Used to uniquely identify attribute, may affect how it is animated
  highlight: Object, // Highlight to display for the attribute (reference structure below)
  indicator: Object, // Indicator to display for the attribute (reference structure below)
  contentStyle: Object, // Style object to apply to day cell content
  contentHoverStyle: Object, // Style object to apply to day cell content when hovered (merged with contentStyle)
  dates: Array[Date or Object], // List of date like values or date ranges (w/ start and end date) to apply the attribute
  order: Number // By default, attributes are layered to display the most data possible, but this may be used for manual ordering
}

// Highlight structure
{
  height: String, // Default: "1.8rem"
  backgroundColor: String, // Default: undefined
  borderColor: String, // Default: undefined
  borderWidth: String, // Default: "0"
  borderStyle: String, // Default: "solid"
  borderRadius: String // Default: "1.8rem"
}

// Indicator structure
{
  diameter: String, // Default: "5px"
  backgroundColor: String, // Default: undefined
  borderColor: String, // Default: undefined
  borderWidth: String, // Default: "0"
  borderStyle: String, // Default: "solid"
  borderRadius: String, // Default: "50%"
}