One of a fixed set of built-in shadow presets.
https://c-rex.net/samples/ooxml/e1/Part4/OOXML_P4_DOCX_ST_PresetShadowVal_topic_ID0EN2WOB.html#topic_ID0EN2WOB
Effect type is always IEffect.Type.PresetShadow.
Returns true if the effect is equal to the other effect.
true
Returns the effect as a set of css strings that are suitable for css.
Optional
Not all effect types will offer an exact css equivalent.
Returns the effect as a JSON object.
One of a fixed set of built-in shadow presets.
See
https://c-rex.net/samples/ooxml/e1/Part4/OOXML_P4_DOCX_ST_PresetShadowVal_topic_ID0EN2WOB.html#topic_ID0EN2WOB