A 42-year-old woman presents with 1 month of shortness of breath on climbing stairs and 1 week of inability to lie flat at night. She has thickened skin on both hands. BP 148/92 mmHg, urinary protein (++) (2g/d), urine sediment shows 10-15 RBCs/HPF. Pericardial effusion is present. ANA positive, weakly positive anti-Scl-70, and anti-SSA positive. The clinical diagnosis is: