basic reset and body centering
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}
html,
body {
  height: 100%;
}
body {
  display: flex;
  justify-content: center;
  align-items: center;
  font-family: Arial, sans-serif;
  background: #e0f0ff;
}

.counter-card {
  background: #fff;
  border-radius: 20px;
  padding: 40px 60px;
  box-shadow: 0 10px 25px rgba(0, 0, 0, 0.1);
  text-align: center;
  width: 280px;
}

.counter-card h1 {
  font-size: 1.4rem;
  margin-bottom: 20px;
}

.display {
  font-size: 3rem;
  margin-bottom: 20px;
  transition: transform 0.15s ease;
}

.display.animate {
  transform: scale(1.2);
}

.buttons {
  display: flex;
  justify-content: space-between;
}

.btn {
  width: 50px;
  height: 50px;
  border: none;
  border-radius: 50%;
  font-size: 1.5rem;
  cursor: pointer;
  color: #fff;
  display: flex;
  justify-content: center;
  align-items: center;
}

.btn.minus {
  background: #e74c3c;
}

.btn.plus {
  background: #2ecc71;
}

.btn.reset {
  background: #3498db;
}

.btn:focus {
  outline: none;
}