* {
  margin: 0;
  padding: 0;
}

body {
  background-color: #f1f2f3;
}

.container {
  box-sizing: border-box;
  width: 100%;
  max-width: 1560px;
  min-width: 1240px;
  margin: 25px auto;
  position: relative;
  color: #333;
}

.container * {
  box-sizing: border-box;
}

header {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  margin-bottom: 25px;
  width: 100%;
}

header h1 {
  font-size: 2.2rem;
  margin-bottom: 10px;
  position: relative;
  display: inline-block;
}

header p {
  opacity: 0.9;
  font-size: 1rem;
}

.book-container {
  position: relative;
  width: 350px;
  height: 502px;
  margin: 0 auto 40px;
  perspective: 1000px;
  cursor: pointer;
}

.book {
  width: 100%;
  height: 100%;
  position: relative;
  transform-style: preserve-3d;
  transition: transform 1s;
}

.book-face {
  position: absolute;
  width: 100%;
  height: 100%;
  backface-visibility: hidden;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 30px;
  padding: 20px;
  border-radius: 12px;
  box-sizing: border-box;
}

.book-front {
  background: url('./book.webp') center/contain no-repeat;
}

.book-back {
  background-color: #fff;
  transform: rotateY(180deg);
}

.answer-text {
  font-size: 2rem;
  font-weight: bold;
  color: #4a4a4a;
  text-align: center;
  text-transform: uppercase;
  text-shadow: 1px 1px 2px rgba(0, 0, 0, 0.1);
}

.answer-english {
  font-size: 1.2rem;
  color: #666;
  font-style: italic;
  text-align: center;
}

.tipbox{
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 20px;
  margin-bottom: 25px;
}

.tipbox p{
  font-size: 1.1rem;
  color: #666;
  display: none;
  padding: 10px 20px;
}

.next-btn {
  background: none;
  border: none;
  color: #4a90e2;
  font-size: 1.1rem;
  cursor: pointer;
  padding: 10px 20px;
  border-radius: 5px;
  transition: background-color 0.3s;
  display: none;
  /* 初始隐藏 */
}

.tipbox .show{
  display: inline-block;
}

.next-btn:hover {
  background-color: rgba(74, 144, 226, 0.1);
}

.instructions {
  background-color: #fff;
  padding: 20px;
  border-radius: 12px;
  box-shadow: 0 5px 15px rgba(0, 0, 0, 0.05);
  margin-bottom: 25px;
  text-align: left;
}

.instructions h2 {
  color: #4a4a4a;
  padding-bottom: 15px;
}

.instructions h3 {
  margin: 10px 0;
}

.instructions ol,.instructions  ul {
  padding-left: 20px;
}

.instructions li,.instructions  p {
  margin-top: 10px;
  line-height: 1.6;
}

.notice {
  position: fixed;
  bottom: 20px;
  left: 50%;
  transform: translateX(-50%);
  background-color: rgba(0, 0, 0, 0.7);
  color: white;
  padding: 15px 30px;
  border-radius: 5px;
  opacity: 0;
  transition: opacity 0.3s;
  z-index: 1000;
}

.notice.show {
  opacity: 1;
}

footer {
  width: 100%;
  text-align: center;
  color: #666;
}

.footer-content {
  display: flex;
  gap: 20px;
  margin-bottom: 20px;
}

.footer-section {
  flex: 1;
  background: #fff;
  padding: 20px;
  border-radius: 12px;
  margin-bottom: 25px;
}

.footer-section h3 {
  color: #4a4a4a;
  margin-bottom: 15px;
}

.footer-section p {
  line-height: 1.6;
  margin: 0;
}

.copyright {
  color: #666;
  font-size: 0.9rem;
}

@keyframes pulse {
  0% {
    transform: scale(1);
  }

  50% {
    transform: scale(1.05);
  }

  100% {
    transform: scale(1);
  }
}

.book-container:hover .book-front {
  animation: pulse 1.5s infinite;
}