Sequestered in the Bernese Alps, the Gstaad Palace in Switzerland is an idyllic retreat for summer vacations or romantic escapes. Recently, the hotel’s rooftop Penthouse Suite was made even more opulent thanks to a renovation overseen by interior designer Marina Nickels. Its 2,583 square feet include three large bedrooms with en suite bathrooms and steam baths, a kitchenette, and a living room complete with wood floors, a fireplace, a dining area, and large windows overlooking the mountains. Decorated in muted…