body {
  font-family: Arial, sans-serif;
  margin: 0;
  background: #f7f7f7;
}

header, footer {
  text-align: center;
  padding: 1rem;
  background: #fff;
}

.container {
  display: grid;
  grid-template-columns: 1fr 2fr 1fr;
  gap: 1rem;
  padding: 1rem;
}

.ad {
  background: #eaeaea;
  display: flex;
  align-items: center;
  justify-content: center;
}

.app {
  background: #fff;
  padding: 2rem;
  text-align: center;
}

.timer {
  font-size: 3rem;
  margin: 1rem 0;
}

button {
  padding: 0.8rem 1.5rem;
  margin: 0.5rem;
  font-size: 1rem;
}