* { box-sizing: border-box; }

body {
  margin: 0;
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: 24px;
  font-family: system-ui, -apple-system, Segoe UI, Roboto, Arial, sans-serif;
  background: radial-gradient(circle at top, #f59e0b, #7c2d12);
  color: #fff7ed;
}

.card {
  width: min(560px, 94vw);
  padding: 24px;
  border-radius: 18px;
  background: rgba(255, 255, 255, 0.1);
  border: 1px solid rgba(251, 146, 60, 0.45);
  box-shadow: 0 16px 40px rgba(0, 0, 0, 0.4);
}

h1 {
  margin: 0 0 16px;
  text-align: center;
  letter-spacing: 0.4px;
}

.label {
  display: block;
  margin-bottom: 8px;
  opacity: 0.9;
}

.row {
  display: flex;
  gap: 10px;
}

#number {
  flex: 1;
  padding: 12px 14px;
  border-radius: 12px;
  border: 1px solid rgba(251, 146, 60, 0.55);
  background: rgba(124, 45, 18, 0.35);
  color: #fff7ed;
  outline: none;
}

#number::placeholder {
  color: rgba(255, 247, 237, 0.6);
}

#number:focus {
  box-shadow: 0 0 0 3px rgba(251, 146, 60, 0.45);
}

#convert-btn {
  padding: 12px 14px;
  border: none;
  border-radius: 12px;
  cursor: pointer;
  font-weight: 700;
  color: #3b1406;
  background: linear-gradient(90deg, #fb923c, #fdba74);
}

#convert-btn:active {
  transform: scale(0.98);
}

.output {
  margin: 16px 0 0;
  padding: 12px 14px;
  border-radius: 12px;
  background: rgba(124, 45, 18, 0.35);
  border: 1px solid rgba(251, 146, 60, 0.4);
  min-height: 44px;
  display: grid;
  align-items: center;
  text-align: center;
  font-weight: 700;
}