:root{font-family:system-ui,-apple-system,Segoe UI,Roboto,"Helvetica Neue",Arial}
body{display:flex;align-items:center;justify-content:center;min-height:100vh;margin:0;background:#f6f7f8;color:#111}
main{width:min(680px,95vw);background:#fff;padding:24px;border-radius:8px;box-shadow:0 6px 20px rgba(0,0,0,0.08)}
h1{margin:0 0 12px;font-size:20px}
form{display:grid;gap:10px}
label{display:flex;flex-direction:column;font-size:13px}
input[type="date"]{padding:8px;border:1px solid #ddd;border-radius:4px;margin-top:6px}
.options{font-size:13px;color:#444}
button{padding:8px 12px;border-radius:6px;border:1px solid #bbb;background:#eee;cursor:pointer}
button[type="submit"]{background:#222;color:#fff;border-color:#222}
#result{margin-top:14px;padding:12px;border-radius:6px;background:#f2f2f2}
footer{margin-top:16px;font-size:12px;color:#666}