* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: -apple-system, "Segoe UI", Roboto, sans-serif;
  background: #f1f5f9;
  color: #1e293b;
}
#app { max-width: 360px; margin: 0 auto; padding: 16px; }
header {
  display: flex; align-items: center; justify-content: space-between;
  margin-bottom: 12px;
}
header h1 { font-size: 18px; margin: 0; }
.badge {
  font-size: 12px; padding: 4px 10px; border-radius: 999px; color: #fff;
}
.badge.on { background: #16a34a; }
.badge.off { background: #94a3b8; }
.badge.warn { background: #f59e0b; }
.card {
  background: #fff; border-radius: 12px; padding: 16px;
  box-shadow: 0 1px 3px rgba(0,0,0,.08); margin-bottom: 12px;
}
.hidden { display: none; }
label { display: block; font-size: 13px; margin-bottom: 10px; }
input {
  width: 100%; padding: 10px; border: 1px solid #cbd5e1; border-radius: 8px;
  font-size: 15px; margin-top: 4px;
}
button {
  cursor: pointer; border: none; border-radius: 8px; padding: 12px;
  font-size: 15px; background: #2563eb; color: #fff; width: 100%;
}
button:hover { opacity: .92; }
.hint { font-size: 12px; color: #64748b; margin: 8px 0 0; }
.keypad {
  display: grid; grid-template-columns: repeat(3, 1fr); gap: 8px;
  margin: 12px 0;
}
.keypad button { background: #e2e8f0; color: #1e293b; font-size: 18px; }
.call { background: #16a34a; }
.hangup { background: #dc2626; }
.answer { background: #16a34a; }
.actions { display: flex; gap: 8px; margin-top: 12px; }
.actions button { flex: 1; }
.peer { font-size: 22px; font-weight: 600; text-align: center; margin: 4px 0; }
.state { text-align: center; color: #64748b; margin: 4px 0; }
.timer { text-align: center; font-size: 28px; font-variant-numeric: tabular-nums; margin: 8px 0; }