body {
 
  font-family: "comic sans ms", sans-serif; 
  padding: 20px;
  background-color: #ffffff;
}


.start-button {
  background-color: #4CAF50; 
  color: white;
  padding: 10px 20px;
  margin-top: 15px;
  border: none;
  border-radius: 5px;
  cursor: pointer;
  font-family: inherit;
  font-size: 1rem;
}

.start-button:hover {
  background-color: #45a049;
}
h1 {
  text-align: center;
  margin-bottom: 20px;
  font-weight: bold;
}


.periodic-table {
  display: grid;
  grid-template-columns: repeat(18, 1fr); 
  gap: 2px; 
  max-width: 1200px;
  margin: 0 auto;
}


.element {
  aspect-ratio: 1 / 1; 
  border: 1px solid #555;
  padding: 2px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  cursor: pointer;
  transition: transform 0.1s;
  color: #000;
}

.element:hover {
  transform: scale(1.2);
  z-index: 10;
  box-shadow: 0 0 8px rgba(0,0,0,0.4);
  border-color: #000;
}


.number { 
  font-size: 0.6rem; 
  align-self: flex-start; 
  margin-left: 2px; 
}
.symbol { 
  font-size: 1.2rem; 
  font-weight: bold; 
  margin: 2px 0; 
}
.name { 
  font-size: 0.55rem; 
  text-align: center; 
}



.element[data-category="alkali-metal"] { background-color: #ff6666; } 
.element[data-category="alkaline-earth-metal"] { background-color: #ffdead; } 
.element[data-category="transition-metal"] { background-color: #ffff99; }
.element[data-category="post-transition-metal"] { background-color: #cccccc; } 
.element[data-category="metalloid"] { background-color: #cccc99; }
.element[data-category="nonmetal"] { background-color: #aaffaa; } 
.element[data-category="halogen"] { background-color: #99ffff; }
.element[data-category="noble-gas"] { background-color: #c0c0c0; }
.element[data-category="lanthanide"] { background-color: #ffbfff; } 
.element[data-category="actinide"] { background-color: #ff99cc; }



.helium { grid-column: 18; }
.boron { grid-column: 13; }
.aluminum { grid-column: 13; }


.lanthanoid-placeholder { grid-column: 3; grid-row: 6; border: none; background: none; }
.actinoid-placeholder { grid-column: 3; grid-row: 7; border: none; background: none; }


.lanthanum { grid-column: 3; grid-row: 9; margin-top: 15px; } 
.cerium { grid-column: 4; grid-row: 9; margin-top: 15px; }
.praseodymium { grid-column: 5; grid-row: 9; margin-top: 15px; }
.neodymium { grid-column: 6; grid-row: 9; margin-top: 15px; }
.promethium { grid-column: 7; grid-row: 9; margin-top: 15px; }
.samarium { grid-column: 8; grid-row: 9; margin-top: 15px; }
.europium { grid-column: 9; grid-row: 9; margin-top: 15px; }
.gadolinium { grid-column: 10; grid-row: 9; margin-top: 15px; }
.terbium { grid-column: 11; grid-row: 9; margin-top: 15px; }
.dysprosium { grid-column: 12; grid-row: 9; margin-top: 15px; }
.holmium { grid-column: 13; grid-row: 9; margin-top: 15px; }
.erbium { grid-column: 14; grid-row: 9; margin-top: 15px; }
.thulium { grid-column: 15; grid-row: 9; margin-top: 15px; }
.ytterbium { grid-column: 16; grid-row: 9; margin-top: 15px; }
.lutetium { grid-column: 17; grid-row: 9; margin-top: 15px; }


.actinium { grid-column: 3; grid-row: 10; }
.thorium { grid-column: 4; grid-row: 10; }
.protactinium { grid-column: 5; grid-row: 10; }
.uranium { grid-column: 6; grid-row: 10; }
.neptunium { grid-column: 7; grid-row: 10; }
.plutonium { grid-column: 8; grid-row: 10; }
.americium { grid-column: 9; grid-row: 10; }
.curium { grid-column: 10; grid-row: 10; }
.berkelium { grid-column: 11; grid-row: 10; }
.californium { grid-column: 12; grid-row: 10; }
.einsteinium { grid-column: 13; grid-row: 10; }
.fermium { grid-column: 14; grid-row: 10; }
.mendelevium { grid-column: 15; grid-row: 10; }
.nobelium { grid-column: 16; grid-row: 10; }
.lawrencium { grid-column: 17; grid-row: 10; }



.modal-overlay {
  display: none;
  position: fixed;
  top: 0; left: 0;
  width: 100%; height: 100%;
  background-color: rgba(0, 0, 0, 0.5);
  z-index: 1000;
}

.modal-content {
  background-color: white;
  margin: 15% auto; 
  padding: 30px;     
  width: 90%;       
  max-width: 600px;  
  border-radius: 12px;
  text-align: center;
  position: relative;
  box-shadow: 0 8px 20px rgba(0,0,0,0.3);
  font-family: inherit; 
}
.close-btn {
  position: absolute;
  top: 10px; right: 15px;
  font-size: 24px;
  font-weight: bold;
  cursor: pointer;
  color: #888;
}

.close-btn:hover { color: #000; }