body{margin:0;font-family:system-ui,Segoe UI,Roboto,sans-serif}#root{width:100%}*{box-sizing:border-box;margin:0;padding:0}:root{--bg:#fff;--text:#1a1a1a;--text-secondary:#666;--button-bg:#1a1a1a;--button-text:#fff}[data-theme=dark]{--bg:#1a1a1a;--text:#fff;--text-secondary:#a0a0a0;--button-bg:#fff;--button-text:#1a1a1a}.app{background-color:var(--bg);min-height:100vh;color:var(--text);justify-content:center;align-items:center;transition:all .3s;display:flex}.container{text-align:center;padding:2rem}h1{margin-bottom:1rem;font-size:3rem;font-weight:700}p{color:var(--text-secondary);margin-bottom:2rem;font-size:1.25rem}.toggle-btn{background-color:var(--button-bg);color:var(--button-text);cursor:pointer;border:none;border-radius:8px;padding:.75rem 1.5rem;font-size:1rem;transition:transform .2s,opacity .2s}.toggle-btn:hover{opacity:.9}.toggle-btn:active{transform:scale(.98)}