:root {
  color-scheme: light dark;
  --bg: #0b0d12;
  --card: #121625;
  --text: #e8ecff;
  --muted: #b7bfdc;
  --accent: #6ea8fe;
  --danger: #ff6b6b;
  --ok: #40c057;
  --border: rgba(255, 255, 255, 0.12);
}

@media (prefers-color-scheme: light) {
  :root {
    --bg: #f5f7ff;
    --card: #ffffff;
    --text: #0b0d12;
    --muted: #4c556a;
    --border: rgba(11, 13, 18, 0.12);
  }
}

* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, Arial, "Noto Sans", "Liberation Sans", sans-serif;
  background: radial-gradient(1200px 800px at 50% 0%, rgba(110,168,254,0.25), transparent 55%),
              radial-gradient(900px 700px at 0% 60%, rgba(64,192,87,0.10), transparent 60%),
              var(--bg);
  color: var(--text);
  min-height: 100svh;
  display: grid;
  place-items: center;
  padding: 24px;
}

.card {
  width: min(560px, 100%);
  background: linear-gradient(180deg, rgba(255,255,255,0.03), transparent 60%), var(--card);
  border: 1px solid var(--border);
  border-radius: 18px;
  padding: 22px 20px 18px;
  box-shadow: 0 20px 60px rgba(0,0,0,0.35);
}

h1 {
  margin: 0 0 8px;
  font-size: 22px;
  letter-spacing: 0.2px;
}

.hint, .footer {
  margin: 0 0 14px;
  color: var(--muted);
  font-size: 13.5px;
  line-height: 1.45;
}

.footer {
  font-size: 27px;
  line-height: 1.25;
}

label { display: grid; gap: 6px; margin: 12px 0; }
label span { font-size: 13px; color: var(--muted); }

input {
  width: 100%;
  border-radius: 12px;
  border: 1px solid var(--border);
  background: rgba(255,255,255,0.02);
  color: var(--text);
  padding: 12px 12px;
  font-size: 15px;
  outline: none;
}
input:focus {
  border-color: rgba(110,168,254,0.7);
  box-shadow: 0 0 0 3px rgba(110,168,254,0.18);
}

button {
  margin-top: 6px;
  width: 100%;
  border: 0;
  border-radius: 12px;
  padding: 12px 14px;
  font-size: 15px;
  font-weight: 600;
  background: linear-gradient(135deg, rgba(110,168,254,0.95), rgba(110,168,254,0.65));
  color: #06102b;
  cursor: pointer;
}
button:disabled { opacity: 0.6; cursor: not-allowed; }

.out {
  margin: 14px 0 0;
  padding: 12px;
  border-radius: 12px;
  border: 1px solid var(--border);
  background: rgba(0,0,0,0.12);
  color: var(--muted);
  white-space: pre-wrap;
  word-break: break-word;
  min-height: 44px;
}
.out.ok { color: var(--ok); }
.out.err { color: var(--danger); }