:root{--background-light: #ffffff;--background-dark: #333333;--text-light: #000000;--text-dark: #ffffff}body{background-color:var(--background-light);color:var(--text-light);transition:background-color .3s ease,color .3s ease}body.dark-mode{background-color:var(--background-dark);color:var(--text-dark)}