Is the css modifier supported? (in animation)

[billbrod]

I have been unable to get the css modifier to work. I copied the animate demo and modified a small portion, to see if I could get it working, and no animation happens.

### Graphical solution procedure

<span class="fragment appear-disappear"></span>

<div data-animate data-load="animate/linear_program.svg">
<!--
{
"animation": [
[],
[
{
"element": "#y_geq_0",
"modifier": "css",
"parameters": [ {"fill": "red"} ]
},
{
"element": "#horizontal_gridline0",
"modifier": "attr",
"duration": 1500,
"parameters": [ { "d": "M 0,210 L 800,690" } ]
},
{
"element": "#y_geq_0",
"modifier": "opacity",
"parameters": [ 0 ]
}
]
]
}
-->
</div>

If instead I do

{
"element": "#y_geq_0",
- "modifier": "css",
- "parameters": [ {"fill": "red"} ]
+ "modifier": "opacity",
+ "parameters": [ 0 ]
},

as in the original demo, the animation happens without an issue.

I have also confirmed that running SVG(#y_geq_0).css({'fill': 'red'}) from the browser console has an effect.

Is css unsupported or am I doing something incorrectly?

I appreciate any help you can offer!