* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: "Microsoft YaHei", "PingFang SC", Arial, sans-serif;
  color: #241b18;
  background:
    linear-gradient(rgba(20, 16, 14, 0.28), rgba(20, 16, 14, 0.4)),
    url("https://images.unsplash.com/photo-1519682337058-a94d519337bc?auto=format&fit=crop&w=1600&q=80")
      center / cover;
}

.app {
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: 28px;
}

.book {
  width: min(92vw, 520px);
  min-height: 560px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 28px;
  padding: 48px 36px;
  text-align: center;
  background: #f4ead7;
  border: 1px solid rgba(54, 36, 25, 0.24);
  border-radius: 8px;
  box-shadow:
    0 22px 60px rgba(0, 0, 0, 0.35),
    inset 0 0 0 10px rgba(255, 255, 255, 0.22);
}

.eyebrow {
  margin: 0;
  font-size: 15px;
  letter-spacing: 0;
  color: #6d5547;
}

h1 {
  margin: 0;
  font-size: 48px;
  font-weight: 700;
}

.answer-panel {
  width: 100%;
  min-height: 150px;
  display: grid;
  place-items: center;
  padding: 28px;
  border-top: 1px solid rgba(82, 57, 40, 0.26);
  border-bottom: 1px solid rgba(82, 57, 40, 0.26);
}

#answer {
  margin: 0;
  font-size: 28px;
  line-height: 1.55;
}

button {
  min-width: 180px;
  min-height: 48px;
  border: 0;
  border-radius: 6px;
  padding: 0 22px;
  font-size: 17px;
  color: #fffaf2;
  background: #6c3428;
  cursor: pointer;
  box-shadow: 0 10px 24px rgba(79, 38, 29, 0.24);
}

button:hover {
  background: #7c4031;
}

button:active {
  transform: translateY(1px);
}

.answer-pop {
  animation: pop 260ms ease;
}

@keyframes pop {
  from {
    opacity: 0;
    transform: translateY(8px);
  }

  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@media (max-width: 520px) {
  body {
    background:
      linear-gradient(rgba(20, 16, 14, 0.15), rgba(20, 16, 14, 0.15)),
      url("cat-mobile.jpg")
        center / cover no-repeat;
  }

  .app {
    padding: 18px;
  }

  .book {
    min-height: 520px;
    padding: 36px 22px;
    background: rgba(244, 234, 215, 0.55);
    backdrop-filter: blur(6px);
    -webkit-backdrop-filter: blur(6px);
  }

  h1 {
    font-size: 38px;
  }

  #answer {
    font-size: 23px;
  }
}