h2, .h2 {
            font-size: 1.5rem;
        }

        .puzzle-input {
            font-family: Consolas;
        }

            .puzzle-input:invalid {
                border: 1px dashed red;
            }

            .puzzle-input.invalid {
                border: 1px dashed red;
            }

            .puzzle-input:invalid:focus {
                border: 2px dashed red;
            }

            .puzzle-input.invalid:focus {
                border: 2px dashed red;
            }

        .invisible {
            opacity: 0;
        }