user/test/com/google/gwt/resources/client/gss/runtimeConditional.gss

.foo {
    width: 100%;
}

/* will be evaluated to false) */
@if (is("custom.one", "foo")) {
    .foo {
        color: black;
    }
}
@elseif (eval("com.google.gwt.resources.client.gss.BooleanEval.FIRST")) {
    /* will be evaluated to false) */
    @if (is("custom.one", "foo")) {
        .foo {
            color: orange;
        }
    }
    @else {
        .foo {
            color: purple;
        }
    }
}
@elseif (eval("com.google.gwt.resources.client.gss.BooleanEval.SECOND")) {
    @if (eval("com.google.gwt.resources.client.gss.BooleanEval.THIRD")) {
        .foo {
            color: black;
        }
    } @else {
        .foo {
            color: khaki;
        }
    }
}
@else {
    .foo {
        color: gray;
    }
}

/* will be evaluated to false */
@if (is("custom.one", "foo")) {
    .foo {
        padding: 5px;
    }
}
/* will be evaluated to true */
@elseif (is("custom.two", "bar")) {
    .foo {
        padding: 10px;
    }
}
/* will be never evaluated */
@elseif (eval("com.google.gwt.resources.client.gss.BooleanEval.FIRST")) {
    .foo {
        padding: 20px;
    }
}

/* Test that we can pass String parameters */
@if (eval('java.lang.Boolean.valueOf("true")')) {
  .foo {
    margin: 100px;
  }
}