body {
  background-color: #0a192f;
  color: #e6f1ff;
  font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
  margin: 0;
  overflow-x: hidden;
  touch-action: manipulation;
}

.game-container {
  max-width: 96vw;
  padding: 2vw 2vw;
  margin: 0 auto;
  box-sizing: border-box;
}

.game-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 2vw;
  margin-bottom: 2vw;
  flex-wrap: wrap;
}

.header-left {
  display: flex;
  align-items: center;
  gap: 3vw;
  flex: 1;
}

.header-right {
  display: flex;
  align-items: center;
  gap: 1vw;
  flex-wrap: wrap;
}

.game-title {
  font-size: clamp(1.4rem, 4.5vw, 1.8rem);
  font-weight: bold;
  color: #64ffda;
}

.stats-container {
  display: flex;
  justify-content: start;
  gap: 2vw;
  flex-wrap: wrap;
}

.score-display,
.level-display,
.timer-display {
  font-size: clamp(0.8rem, 2.8vw, 1rem);
  font-weight: bold;
  color: #64ffda;
  background-color: #112240;
  padding: 0.6rem;
  border-radius: 0.5rem;
  min-width: 70px;
  text-align: center;
}

.elements-container {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  align-items: center;
  gap: 0.5vw;
  padding: 0.8rem 0;
  min-height: 2.5rem;
}

.element-box {
  color: #e6f1ff;
  width: clamp(36px, 3.8vw, 40px);
  height: clamp(36px, 3.8vw, 40px);
  border: 1px solid #333;
  padding: 0.2rem;
  display: grid;
  grid-template-rows: 20% 40% 20% 20%;
  cursor: move;
  user-select: none;
  background-color: #f0f0f05e;
  border-radius: 4px;
  transition: transform 150ms ease-in;
  touch-action: none;
  -webkit-user-drag: element;
}

.element-box:hover {
  transform: scale(1.4);
  z-index: 1;
  background-color: #f0f0f0ab;
}

.drop-zone .element-box:hover {
  transform: none;
  background: unset;
}

.element-box .atomic-number {
  font-size: clamp(7px, 1.3vw, 9px);
  text-align: left;
  align-self: start;
}

.element-box .symbol {
  font-size: clamp(11px, 1.8vw, 13px);
  font-weight: bold;
  text-align: center;
  align-self: center;
}

.element-box .name {
  font-size: clamp(7px, 1.3vw, 9px);
  text-align: center;
  align-self: center;
  text-overflow: ellipsis;
  overflow: hidden;
  white-space: nowrap;
}

.element-box:hover .name {
  font-size: clamp(5px, 1vw, 7px);
}

.element-box .mass {
  font-size: clamp(5px, 1vw, 7px);
  text-align: center;
  align-self: center;
}

.element-box.dragging {
  opacity: 0.5;
  z-index: 1000;
}

.element-box.shake {
  animation: shake 0.2s;
}

.periodic-table-container {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1.5vw;
  padding: 0.8rem;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  scroll-snap-type: x mandatory; /* Snap to grid for smoother scrolling */
}

.periodic-grid {
  display: grid;
  grid-template-columns: repeat(18, clamp(32px, 4vw, 40px)); /* Smaller cells */
  gap: clamp(2px, 0.4vw, 4px); /* Tighter gaps */
  width: max-content;
  scroll-snap-align: center;
}

.drop-zone {
  width: clamp(32px, 4vw, 40px);
  height: clamp(32px, 4vw, 40px);
  border: 1px dashed #666;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0.5;
  border-radius: 4px;
  font-size: clamp(6px, 1vw, 8px); /* Smaller font for placeholders */
}

.drop-zone[data-group="alkali-metal"] { background-color: #ff5f56; }
.drop-zone[data-group="alkaline-earth"] { background-color: #ffbd2e; }
.drop-zone[data-group="transition"] { background-color: #ff9f1a; }
.drop-zone[data-group="post-transition"] { background-color: #27c93f; }
.drop-zone[data-group="metalloid"] { background-color: #00b4d8; }
.drop-zone[data-group="nonmetal"] { background-color: #1e90ff; }
.drop-zone[data-group="noble-gas"] { background-color: #9b5de5; }
.drop-zone[data-group="lanthanide"],
.drop-zone[data-group="lanthanide-placeholder"] { background-color: #dd32f4; }
.drop-zone[data-group="actinide"],
.drop-zone[data-group="actinide-placeholder"] { background-color: #ff66c4; }

.drop-zone[data-group="lanthanide-placeholder"],
.drop-zone[data-group="actinide-placeholder"] {
  opacity: 0.5;
  font-size: clamp(6px, 1vw, 8px);
  font-style: italic;
}

.drop-zone.correct {
  opacity: 1;
  border-style: solid;
}

.drop-zone.correct-hover {
  background-color: rgba(100, 255, 218, 0.1);
  outline: 2px dashed #64ffda;
}

.drop-zone.incorrect {
  background-color: color-mix(in srgb, var(--indicator-color) 25%, transparent);
  outline: 2px solid var(--indicator-color);
  box-shadow: 0 0 6px var(--indicator-color);
}

.drop-zone.correct .element-box {
  border: none;
  animation: placeElement 0.5s ease-out forwards;
}

.sub-periodic-grid {
  display: grid;
  grid-template-columns: repeat(15, clamp(32px, 4vw, 40px));
  gap: clamp(2px, 0.4vw, 4px);
  justify-content: center;
  margin-top: 0.8rem;
  scroll-snap-align: center;
}

.drop-zone[data-group="spacer"],
.drop-zone[data-group="empty"] {
  border: none;
  background: none;
  pointer-events: none;
}

.legend {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 1rem;
  padding: 0.8rem;
}

.legend-item {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  font-size: clamp(10px, 1.8vw, 12px);
}

.color-box {
  width: clamp(12px, 1.8vw, 16px);
  height: clamp(12px, 1.8vw, 16px);
  border: 1px solid #666;
  border-radius: 4px;
}

.color-box.alkali-metal { background-color: #ff5f56; }
.color-box.alkaline-earth { background-color: #ffbd2e; }
.color-box.transition { background-color: #ff9f1a; }
.color-box.post-transition { background-color: #27c93f; }
.color-box.metalloid { background-color: #00b4d8; }
.color-box.nonmetal { background-color: #1e90ff; }
.color-box.noble-gas { background-color: #9b5de5; }
.color-box.lanthanide { background-color: #dd32f4; }
.color-box.actinide { background-color: #ff66c4; }

.button {
  padding: 0.4rem 0.8rem;
  font-size: clamp(12px, 2.2vw, 14px);
  cursor: pointer;
  background-color: #233554;
  color: #64ffda;
  border: 1px solid darkslategrey;
  border-radius: 8px;
  transition: all 0.3s ease;
  touch-action: manipulation;
}

.button:hover {
  background-color: rgba(100, 255, 218, 0.1);
}

.reset {
  border-color: #ff5f56;
  color: #ff5f56;
}

.reset:hover {
  background-color: rgba(255, 95, 86, 0.1);
}

.game-container.paused::after {
  content: "PAUSED";
  position: fixed;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  background-color: rgba(0, 0, 0, 0.8);
  color: #64ffda;
  padding: 0.8rem 1.6rem;
  font-size: clamp(1rem, 3.5vw, 1.2rem);
  border-radius: 6px;
  z-index: 1000;
}

.game-container.paused .element-box,
.game-container.paused .drop-zone {
  pointer-events: none;
  opacity: 0.5;
}

.celebration-overlay {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(10, 25, 47, 0.85);
  display: flex;
  justify-content: center;
  align-items: center;
  z-index: 1000;
  animation: fadeIn 0.5s ease-out;
}

.celebration-message {
  background: #112240;
  padding: 1.5rem;
  border-radius: 10px;
  text-align: center;
  animation: scaleIn 0.5s ease-out;
}

.celebration-message h2 {
  color: #64ffda;
  font-size: clamp(1.4rem, 3.5vw, 1.8rem);
  margin-bottom: 0.8rem;
}

.celebration-message p {
  color: #e6f1ff;
  font-size: clamp(0.9rem, 2.8vw, 1.1rem);
  margin: 0.4rem 0;
}

.celebration-button {
  background-color: #64ffda;
  color: #0a192f;
  border: none;
  padding: 0.6rem 1.2rem;
  border-radius: 5px;
  font-size: clamp(0.9rem, 2.2vw, 1rem);
  margin-top: 0.8rem;
  cursor: pointer;
  transition: all 0.3s ease;
}

.celebration-button:hover {
  transform: scale(1.05);
  box-shadow: 0 0 15px rgba(100, 255, 218, 0.3);
}

@keyframes scaleIn {
  from { transform: scale(0.8); opacity: 0; }
  to { transform: scale(1); opacity: 1; }
}

@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.5; }
}

@keyframes fadeOut {
  from { opacity: 1; }
  to { opacity: 0; }
}

@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

@keyframes placeElement {
  0% { transform: scale(0.8); opacity: 0; }
  50% { transform: scale(1.1); }
  100% { transform: scale(1); opacity: 1; }
}

@keyframes shake {
  0%, 100% { transform: translateX(0); }
  25% { transform: translateX(-2px); }
  75% { transform: translateX(2px); }
}

/* Media Queries for Mobile Devices */
@media (max-width: 768px) {
  .game-container {
    padding: 2vw;
  }

  .game-header {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.8rem;
  }

  .header-left, .header-right {
    width: 100%;
    justify-content: center;
  }

  .header-right {
    gap: 0.4rem;
  }

  .periodic-grid {
    grid-template-columns: repeat(18, clamp(28px, 4.2vw, 32px)); /* Smaller cells for tablets */
    gap: clamp(1px, 0.3vw, 3px);
  }

  .drop-zone {
    width: clamp(28px, 4.2vw, 32px);
    height: clamp(28px, 4.2vw, 32px);
    font-size: clamp(5px, 0.9vw, 7px);
  }

  .sub-periodic-grid {
    grid-template-columns: repeat(15, clamp(28px, 4.2vw, 32px));
    gap: clamp(1px, 0.3vw, 3px);
  }

  .element-box {
    width: clamp(28px, 4.2vw, 32px);
    height: clamp(28px, 4.2vw, 32px);
    padding: 0.15rem;
  }

  .element-box .atomic-number,
  .element-box .name,
  .element-box .mass {
    font-size: clamp(5px, 1.1vw, 7px);
  }

  .element-box .symbol {
    font-size: clamp(9px, 1.6vw, 11px);
  }

  .element-box:hover .name {
    font-size: clamp(4px, 0.9vw, 6px);
  }

  .legend {
    gap: 0.8rem;
    padding: 0.4rem;
  }

  .legend-item {
    font-size: clamp(9px, 1.6vw, 11px);
  }

  .color-box {
    width: clamp(10px, 1.5vw, 14px);
    height: clamp(10px, 1.5vw, 14px);
  }

  .button {
    padding: 0.3rem 0.6rem;
    font-size: clamp(11px, 1.8vw, 13px);
  }
}

@media (max-width: 480px) {
  .periodic-grid {
    grid-template-columns: repeat(18, clamp(24px, 4.5vw, 28px)); /* Even smaller for phones */
    gap: clamp(1px, 0.2vw, 2px);
  }

  .drop-zone {
    width: clamp(24px, 4.5vw, 28px);
    height: clamp(24px, 4.5vw, 28px);
    font-size: clamp(4px, 0.8vw, 6px);
  }

  .sub-periodic-grid {
    grid-template-columns: repeat(15, clamp(24px, 4.5vw, 28px));
    gap: clamp(1px, 0.2vw, 2px);
  }

  .element-box {
    width: clamp(24px, 4.5vw, 28px);
    height: clamp(24px, 4.5vw, 28px);
    padding: 0.1rem;
  }

  .element-box .atomic-number,
  .element-box .name,
  .element-box .mass {
    font-size: clamp(4px, 0.9vw, 6px);
  }

  .element-box .symbol {
    font-size: clamp(7px, 1.4vw, 9px);
  }
}

@media (max-width: 360px) {
  .periodic-grid {
    grid-template-columns: repeat(18, clamp(20px, 4.8vw, 24px)); /* Smallest size for tiny screens */
    gap: clamp(0.5px, 0.15vw, 1.5px);
  }

  .drop-zone {
    width: clamp(20px, 4.8vw, 24px);
    height: clamp(20px, 4.8vw, 24px);
    font-size: clamp(3px, 0.7vw, 5px);
  }

  .sub-periodic-grid {
    grid-template-columns: repeat(15, clamp(20px, 4.8vw, 24px));
    gap: clamp(0.5px, 0.15vw, 1.5px);
  }

  .element-box {
    width: clamp(20px, 4.8vw, 24px);
    height: clamp(20px, 4.8vw, 24px);
    padding: 0.08rem;
  }

  .element-box .atomic-number,
  .element-box .name,
  .element-box .mass {
    font-size: clamp(3px, 0.8vw, 5px);
  }

  .element-box .symbol {
    font-size: clamp(6px, 1.3vw, 8px);
  }
}