:root{--bg-color: #fafafa;--text-color: #222;--tube-color: #ffffff;--tube-border: 1px solid rgba(0, 0, 0, .08);--tube-shadow: 0 2px 8px rgba(0, 0, 0, .06);--selected-highlight: #4d8af0;--transition: all .2s ease-in-out}body{font-family:Georgia,Times New Roman,serif;background-color:var(--bg-color);color:var(--text-color);display:flex;flex-direction:column;align-items:center;justify-content:center;min-height:100vh;margin:0;line-height:1.6;width:100%}