Quadrant: Point Styles
`classDef` and inline styles set a point's `color`, `radius`, `stroke-color` and `stroke-width`; inline styles win over the class.
quadrant-point-styles.mmd
quadrantChart
x-axis Left
y-axis Bottom --> Top
quadrant-1 Q1
classDef c1 color: #ff3300, radius: 10, stroke-color: #00aa33, stroke-width: 5px
A:::c1: [0.9, 0.0]
B: [0.1, 1] radius: 20, color: #00aa00
C: [0.5, 0.5] stroke-color: #0000ff, stroke-width: 3px