body {
  font-family: 'Arial', sans-serif;
  margin: 0;
  padding: 0;
  background: #f1f1f1;
  color: #333;
  text-align: center;
}

.start-screen {
  padding: 40px 20px;
}

.logo {
  width: 150px;
  max-width: 100%;
  margin-bottom: 20px;
}

input, button {
  display: block;
  margin: 10px auto;
  padding: 12px;
  font-size: 1rem;
  width: 90%;
  max-width: 400px;
  border-radius: 6px;
  border: 1px solid #ccc;
}

button {
  background-color: #007bff;
  color: white;
  border: none;
  cursor: pointer;
}

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

#timer {
  font-weight: bold;
  margin: 20px;
}

.card {
  width: 90%;
  max-width: 600px;
  height: 350px;
  margin: 20px auto;
  perspective: 1000px;
  position: relative;
}

.card-inner {
  position: relative;
  width: 100%;
  height: 100%;
  transition: transform 0.8s;
  transform-style: preserve-3d;
}

.card.flipped .card-inner {
  transform: rotateY(180deg);
}

.card-front,
.card-back {
  position: absolute;
  width: 100%;
  height: 100%;
  backface-visibility: hidden;
  padding: 20px;
  border: 2px solid #007bff;
  border-radius: 10px;
  overflow-y: auto;
  box-sizing: border-box;
  background-color: white;
}

.card-front {
  font-size: 1.2rem;
}

.card-back {
  transform: rotateY(180deg);
  text-align: left;
}

.hidden {
  display: none;
}

.last-message {
  color: red;
  font-weight: bold;
  margin: 10px 0;
}

.controls {
  margin-top: 20px;
}

pre {
  white-space: pre-wrap;
  text-align: left;
  font-family: inherit;
}