:root {
  /* Responsive root font size: clamps between 14px and 18px based on viewport width */
  font-size: clamp(14px, 1vw + 12px, 18px);
}

:root {
  height: 100%;
}

html, body, #root {
  height: 100%;
  margin: 0;
  overflow: hidden; /* prevent page scrollbars */
}

.app {
  width: 100vw;
  height: 100vh;
  padding: 0; /* move padding to inner container to avoid overflow with 100vw/100vh */
  box-sizing: border-box;
  overflow: hidden;
}

h1 {
  margin-bottom: clamp(12px, 1.5vw, 20px);
  color: #2c3e50;
  font-size: clamp(1.2rem, 2vw + 0.5rem, 2rem);
}

.container {
  background: white;
  border-radius: 8px;
  padding: clamp(20px, 2vw + 10px, 32px);
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
  text-align: center;
}

button {
  margin-top: clamp(12px, 2vw, 20px);
  padding: clamp(8px, 1vw + 6px, 12px) clamp(14px, 2vw + 8px, 22px);
  font-size: clamp(0.85rem, 0.8vw + 0.6rem, 1rem);
  background-color: #007bff;
  color: white;
  border: none;
  border-radius: 6px;
  cursor: pointer;
  transition: background-color 0.3s;
}

button:hover {
  background-color: #0056b3;
}

button:active {
  transform: scale(0.98);
}