Theme action

Use this action with change({ id: 'Theme', context }).

Context

• id?: Get | Update (Update is assumed if omitted)
• backgroundColor
• axis: { gridLinesColor, textColor, crosshairColor, gridLinesStyle }
• fontSize: { chart, xAxis, yAxis } (numbers in pixels)

Behavior

Theme supports:

• Get: returns current theme values in the same shape as Update context.

• Update: applies provided theme values.

• backgroundColor sets chart background.

• axis applies shared styling for both axes.

• axis.gridLinesColor and axis.gridLinesStyle also apply to Y-axis minor grid lines.

• fontSize values are optional and can be set independently.