* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: #061525;
  color: #eef9ff;
  font-family: Arial, Helvetica, sans-serif;
}

.app {
  max-width: 1100px;
  margin: auto;
  padding: 24px;
}

h2 {
  margin: 0 0 10px;
  font-size: clamp(23px, 3vw, 32px);
}

.intro {
  color: #b7d9e8;
  font-size: 17px;
  margin-bottom: 22px;
}

.controls {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-bottom: 18px;
}

button {
  background: #17415d;
  border: 1px solid #376e89;
  color: white;
  padding: 12px 18px;
  border-radius: 9px;
  font-size: 15px;
  font-weight: 600;
  cursor: pointer;
}

button:hover {
  background: #24617d;
}

button.selected,
button.primary {
  background: #16c8e2;
  color: #061525;
  border-color: #16c8e2;
}

.scene {
  background: #081e32;
  border: 1px solid #2c536e;
  border-radius: 15px;
  padding: 12px;
}

canvas {
  display: block;
  width: 100%;
  height: auto;
}

.message {
  background: #123a54;
  border-left: 4px solid #18d0e8;
  padding: 17px;
  border-radius: 9px;
  margin-top: 18px;
  font-size: 17px;
  line-height: 1.5;
}

.takeaway {
  color: #d4e8f2;
  font-size: 16px;
  line-height: 1.6;
  margin-top: 18px;
}

@media (max-width: 600px) {
  .app {
    padding: 12px;
  }

  button {
    padding: 10px 12px;
    font-size: 13px;
  }

  .message {
    font-size: 15px;
  }
}