:root {
  --bg: #f8fafc;
  --fg: #0f172a;
  --muted: #64748b;
  --field: #ffffff;
  --border: #cbd5e1;
  --call: #16a34a;
  --hangup: #dc2626;
  --primary: #2563eb;
  color-scheme: light dark;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f172a;
    --fg: #e2e8f0;
    --muted: #94a3b8;
    --field: #1e293b;
    --border: #334155;
  }
}
* { box-sizing: border-box; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font: 16px/1.4 system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
}
main { max-width: 420px; margin: 0 auto; padding: 24px 16px; }
h1 { font-size: 1.4rem; margin: 0 0 24px; }
label { display: block; margin-bottom: 16px; color: var(--muted); font-size: 0.9rem; }
input {
  display: block; width: 100%; margin-top: 6px; padding: 14px;
  font-size: 1.4rem; color: var(--fg); background: var(--field);
  border: 1px solid var(--border); border-radius: 10px;
}
button {
  width: 100%; padding: 16px; font-size: 1.1rem; font-weight: 600;
  border: 1px solid var(--border); border-radius: 10px;
  background: var(--field); color: var(--fg); cursor: pointer;
}
button:disabled { opacity: 0.5; }
.primary { background: var(--primary); border-color: var(--primary); color: #fff; }
.call { background: var(--call); border-color: var(--call); color: #fff; font-size: 1.3rem; }
.hangup { background: var(--hangup); border-color: var(--hangup); color: #fff; }
.link { background: none; border: none; color: var(--muted); font-weight: 400; font-size: 0.9rem; margin-top: 24px; }
.row { display: flex; gap: 12px; }
.keypad {
  display: grid; grid-template-columns: repeat(3, 1fr); gap: 10px;
  margin: 0 0 16px;
}
.keypad button {
  padding: 10px 0; font-size: 1.5rem; font-weight: 500;
  display: flex; flex-direction: column; align-items: center; line-height: 1.1;
  touch-action: manipulation; user-select: none;
}
.keypad button:active { background: var(--border); }
.keypad small { font-size: 0.6rem; color: var(--muted); letter-spacing: 0.08em; min-height: 0.8em; }
.sent-digits {
  text-align: center; font-size: 1.3rem; letter-spacing: 0.15em;
  font-variant-numeric: tabular-nums; min-height: 1.4em; margin: 0 0 12px;
  overflow-wrap: anywhere;
}
#timer { font-size: 2rem; text-align: center; font-variant-numeric: tabular-nums; margin: 16px 0; }
#status { min-height: 1.4em; color: var(--muted); text-align: center; }
#status.error { color: var(--hangup); }