It might be required for you to import the package if you encounter any issues (like casting an Array), so better be safe than sorry and add the import.
import crafttweaker.text.IStyle;

ZenGetter	ZenSetter	Tipo
ZenGetter parent	ZenSetter parent	Tipo IStyle
ZenGetter bold	ZenSetter bold	Tipo bool
ZenGetter italic	ZenSetter italic	Tipo bool
ZenGetter underline	ZenSetter underline	Tipo bool
ZenGetter strikethrough	ZenSetter strikethrough	Tipo bool
ZenGetter obfuscated	ZenSetter obfuscated	Tipo bool
ZenGetter inserimento	ZenSetter inserimento	Tipo bool
ZenGetter color	ZenSetter color	Tipo string

• IStyle createShallowCopy();

Creates a shallow copy of this style. Changes to this instance's values will not be reflected in the copy, but changes to the parent style's values WILL be reflected in both this instance and the copy, wherever either does not override a value.

• IStyle createDeepCopy();

Creates a deep copy of this style. No changes to this instance or its parent style will be reflected in the copy.