body {
  margin: 0;
  padding: 0;
  font-family: 'Orbitron', sans-serif;
  height: 100vh;
  overflow: hidden;
  color: #0ff;
}

#background {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-image: url('./sprites/bg7.jpg');
  background-size: cover;
  background-position: center;
  background-repeat: no-repeat;
  z-index: -2;
}

#mainContent {
  height: 100%;
  width: 100%;
  position: relative;
}

#instructionBtn {
  position: absolute;
  top: 20px;
  left: 20px;
  background: none;
  border: none;
  cursor: pointer;
  z-index: 2;
}

#instructionBtn img {
  width: 50px;
  height: 50px;
  filter: drop-shadow(0 0 5px #0ff);
}

.glossy-panel {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  background: rgba(20, 20, 30, 0.8);
  border: 2px solid #0ff;
  border-radius: 20px;
  box-shadow: 0 0 20px #0ff;
  padding: 40px;
  text-align: center;
  backdrop-filter: blur(10px);
  z-index: 1;
}

.game-title {
  font-size: 48px;
  color: #0ff;
  text-shadow: 0 0 10px #0ff;
  margin-bottom: 30px;
}

#normalModeBtn {
  font-family: 'Orbitron', sans-serif;
  padding: 15px 40px;
  background: #0ff;
  color: #000;
  border: none;
  border-radius: 10px;
  font-weight: bold;
  font-size: 18px;
  cursor: pointer;
  box-shadow: 0 0 15px #0ff;
  transition: all 0.3s ease;
}

#normalModeBtn:hover {
  transform: scale(1.05);
  box-shadow: 0 0 20px #0ff, 0 0 40px #0cf;
}

#instructionPopup {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  backdrop-filter: blur(6px);
  background-color: rgba(0, 0, 0, 0.6);
  justify-content: center;
  align-items: center;
  z-index: 1000;
}

.popup-content {
  background: #111;
  border: 2px solid #0ff;
  border-radius: 15px;
  padding: 30px;
  color: #fff;
  width: 90%;
  max-width: 800px;
  box-shadow: 0 0 20px #0ff;
  text-align: justify;
}

.popup-content h2 {
  margin-bottom: 10px;
  color: #0ff;
  text-align: center;
}

.popup-content p {
  font-size: 14px;
  line-height: 1.6;
}

.popup-content button {
  font-family: 'Orbitron', sans-serif;
  margin-top: 20px;
  padding: 10px 20px;
  background: #0ff;
  color: #000;
  border: none;
  border-radius: 8px;
  cursor: pointer;
  font-weight: bold;
  box-shadow: 0 0 10px #0ff;
}

.popup-content button:hover {
  background: #0cf;
}