:root{--bg:#f7f8fb;--accent:#0b63d6;--muted:#666}body{margin:0;font-family:Inter,ui-sans-serif,system-ui,-apple-system,Segoe UI,Roboto,Helvetica Neue,Arial;background:var(--bg);color:#111}.app-root{min-height:100vh;display:flex;flex-direction:column}header{background:#fff;padding:12px 20px;box-shadow:0 1px 4px #0000000f;display:flex;align-items:center;justify-content:space-between}nav button{margin-left:8px;padding:8px 12px;border-radius:6px;border:1px solid transparent;background:transparent;cursor:pointer}nav button.active{background:var(--accent);color:#fff}main{flex:1;padding:24px}footer{padding:12px 20px;background:#fff;text-align:center;color:var(--muted)}