:root {
  --primary-color: #3a506b;
  --secondary-color: #5bc0be;
  --tertiary-color: #6fffe9;
  --background-color: #0b132b;
  --text-color: #f0f0f0;
  --metal-color: #7395ae;
  --nonmetal-color: #557a95;
  --noble-gas-color: #5d5c61;
  --alkali-metal-color: #ff7e6b;
  --alkaline-earth-color: #ffd166;
  --transition-metal-color: #ef476f;
  --metalloid-color: #06d6a0;
  --post-transition-color: #118ab2;
  --lanthanide-color: #9d4edd;
  --actinide-color: #7b2cbf;
  --halogen-color: #52b788;
  --locked-color: #333;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: "Arial", sans-serif;
  background-color: var(--background-color);
  color: var(--text-color);
  line-height: 1.6;
}

.game-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 20px;
}

header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 30px;
  padding-bottom: 10px;
  border-bottom: 2px solid var(--secondary-color);
}

h1 {
  color: var(--tertiary-color);
}

.player-stats {
  display: flex;
  gap: 20px;
}

.periodic-table {
  display: grid;
  grid-template-columns: repeat(18, 1fr);
  grid-gap: 4px;
  margin-bottom: 20px;
}

.element {
  position: relative;
  padding: 8px 4px;
  background-color: var(--primary-color);
  border: 1px solid var(--secondary-color);
  border-radius: 4px;
  text-align: center;
  cursor: pointer;
  transition: transform 0.2s, box-shadow 0.2s;
}

.element:hover {
  transform: scale(1.1);
  box-shadow: 0 0 10px var(--tertiary-color);
  z-index: 1;
}

.element.locked {
  background-color: var(--locked-color);
  color: #666;
  cursor: not-allowed;
}

.element-symbol {
  font-size: 18px;
  font-weight: bold;
}

.element-number {
  position: absolute;
  top: 2px;
  left: 4px;
  font-size: 10px;
}

.element-name {
  font-size: 8px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.question-area,
.boss-battle,
.element-details {
  background-color: var(--primary-color);
  border-radius: 8px;
  padding: 20px;
  margin-top: 20px;
}

.answer-option {
  background-color: var(--secondary-color);
  color: var(--background-color);
  padding: 10px;
  margin: 8px 0;
  border-radius: 4px;
  cursor: pointer;
}

.answer-option:hover {
  background-color: var(--tertiary-color);
}

.health-bar {
  height: 20px;
  background-color: #333;
  border-radius: 10px;
  margin: 10px 0;
  overflow: hidden;
}

.health-bar-fill {
  height: 100%;
  background-color: #ff5555;
  width: 100%;
  transition: width 0.5s;
}

button {
  background-color: var(--secondary-color);
  color: var(--background-color);
  border: none;
  padding: 10px 20px;
  border-radius: 4px;
  cursor: pointer;
  font-weight: bold;
  margin-top: 10px;
}

button:hover {
  background-color: var(--tertiary-color);
}

.hidden {
  display: none;
}

.modal {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: rgba(0, 0, 0, 0.7);
  display: flex;
  justify-content: center;
  align-items: center;
  z-index: 100;
}

.modal-content {
  background-color: var(--primary-color);
  padding: 30px;
  border-radius: 8px;
  max-width: 600px;
  position: relative;
}

.close-btn {
  position: absolute;
  top: 10px;
  right: 10px;
  background: none;
  color: var(--text-color);
  font-size: 24px;
  cursor: pointer;
}

.element-details {
  position: relative;
}

.element.alkali-metal {
  background-color: var(--alkali-metal-color);
}
.element.alkaline-earth {
  background-color: var(--alkaline-earth-color);
}
.element.transition-metal {
  background-color: var(--transition-metal-color);
}
.element.metalloid {
  background-color: var(--metalloid-color);
}
.element.post-transition {
  background-color: var(--post-transition-color);
}
.element.nonmetal {
  background-color: var(--nonmetal-color);
}
.element.noble-gas {
  background-color: var(--noble-gas-color);
}
.element.lanthanide {
  background-color: var(--lanthanide-color);
}
.element.actinide {
  background-color: var(--actinide-color);
}
.element.halogen {
  background-color: var(--halogen-color);
}

.game-controls {
  display: flex;
  justify-content: center;
  gap: 20px;
  margin-top: 20px;
}

.boss-element {
  font-size: 48px;
  text-align: center;
  margin: 20px 0;
}

.game-instructions {
  background-color: var(--primary-color);
  padding: 15px;
  margin-top: 20px;
  border-radius: 8px;
  border: 1px solid var(--secondary-color);
}

.game-instructions h3 {
  color: var(--tertiary-color);
  margin-bottom: 10px;
}