* { box-sizing: border-box; }
body { font-family: Arial, Helvetica, sans-serif; margin:0; padding:0; background:#f6f8fa; }
.container { max-width:900px; margin:40px auto; background:white; padding:20px; border-radius:6px; box-shadow:0 2px 6px rgba(0,0,0,0.08); }
header { display:flex; justify-content:space-between; padding:10px 20px; background:#1f2937; color:white; }
header a { color:white; text-decoration:none; }
.error { color:#b91c1c; }
.controls { margin-top:12px; }
.controls button { padding:12px 18px; font-size:16px; margin-right:8px; }
#history-list { list-style:none; padding-left:0; }
.admin-button { background:#f59e0b; padding:6px 10px; border-radius:4px; }
.logout { background:#ef4444; padding:6px 10px; border-radius:4px; }