user/test/com/google/gwt/resources/converter/conditional.gss

@if (is("user.agent", "ie6") || is("user.agent", "opera")) {
  .blop {
    color: wheat;
  }
}
@elseif (is("user.agent", "ie8")) {
  @if (is("local", "en")) {
    .blop {
      color: black;
    }
  }
  @elseif (is("local", "fr")) {
    .blop {
      color: black;
    }
  }
}
@else  {
  .blop {
    color: black;
  }
}

@if (eval('com.foo.BAR')) {
  .blop {
    color: black;
  }

  @if (eval('com.foo.BAR2')) {
    .blop {
      color: black;
    }
  }
  @else  {
    .blop {
      color: black;
    }
  }
}
@elseif (eval('com.foo.foo()')) {
  .blop {
    color: black;
  }
}

@if (eval('com.foo.BAR')) {
  .blop {
    color: black;
  }
}

@if (eval('com.foo.foo()')) {
  .blop {
    color: black;
  }
}

@if (eval('com.foo.foo("blop")')) {
  .blop {
    color: black;
  }
}

@if (is("property1", "desktop")) {
  .foo3 {
  }

  @if (is("property2", "true")) {
    .foo1 {
    }
  }
  @else  {
    .foo2 {
    }
  }
}
@elseif (is("property1", "blop")) {
  .foo3 {
  }
}
@elseif (is("property1", "blop2")) {
  @if (is("property2", "true")) {
    .foo4 {
    }
  }
}
@else  {
  @if (is("property2", "true")) {
    .foo4 {
    }
  }
  @else  {
    .foo5 {
    }
  }

  .foo6 {
  }

  @if (is("property1", "tablet")) {
    .foo7 {
    }
  }
  @else  {
    .foo8 {
    }
  }
}

@if (!is("property3", "foo") && !is("property3", "bar") && !is("property3", "baz")) {
  .foo8 {
    color: black;
  }
}

@if (eval('CONSTANT_DEFINED_ON_INTERFACE')) {
  .foo9 {
    color: red;
  }
}
@elseif (eval('CONSTANT_DEFINED_ON_INTERFACE2')) {
  .foo9 {
    color: blue;
  }
}

@if (!WILL_MATCH_A_CONFIGURATION_PROPERTY) {
  .foo10 {
    color: red;
  }
}
@elseif (WILL_MATCH_A_CONFIGURATION_PROPERTY2) {
  .foo10 {
    color: blue;
  }
}

@if (!WILL_MATCH_A_CONFIGURATION_PROPERTY) {
  .foo11 {
    color: red;
  }
}

@if (WILL_MATCH_A_CONFIGURATION_PROPERTY2) {
  .foo12 {
    color: red;
  }
}