:root{background-color:#000}*{margin:0;padding:0}.container{display:flex;justify-content:center;align-items:center;height:100vh}.casio{border:2px black solid;width:20rem;height:28.5rem;background-color:#fff;border-radius:2%}.formulaScreen,.outputScreen{display:flex;justify-content:right;padding:3px;height:25px}.formulaScreen{color:#000157;font-size:1.5rem}.outputScreen{color:#000;font-size:2rem}.button-container{padding:8px;display:grid;grid-template-columns:repeat(4,1fr);gap:3px}button{font-size:1.5em;padding:20px;cursor:pointer;color:#7fff00;background-color:#000}#zero,#ac{grid-column:span 2}#equal{grid-row:span 2}