body { background-color: #f9f9f9; font-family: "Hiragino Maru Gothic ProN", "UD デジタル教科書体", sans-serif; color: #222; padding: 2em; max-width: 680px; margin: auto; line-height: 1.9; } h1 { text-align: center; font-size: 1.8em; margin-bottom: 1.4em; } h2 { font-size: 1.3em; margin-top: 2em; color: #333…