* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: Arial, sans-serif;
}

body {
  background: #0f172a;
  color: #fff;
  height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
}

.app {
  text-align: center;
}

h2 {
  margin-bottom: 30px;
}

#pttBtn {
  width: 220px;
  height: 220px;
  border-radius: 50%;
  border: none;
  background: #16a34a;
  color: #fff;
  font-size: 20px;
  font-weight: bold;
  cursor: pointer;
  transition: 0.2s;
}

#pttBtn:active {
  background: #22c55e;
  transform: scale(0.95);
}

#status {
  margin-top: 20px;
  font-size: 16px;
  color: #38bdf8;
}