* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: Arial, sans-serif;
}

body {
    background-color: #f5f5f5;
    padding: 20px;
}

h1 {
    text-align: center;
    margin-bottom: 20px;
}

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

.periodic-table {
    display: grid;
    grid-template-columns: repeat(18, 1fr);
    grid-gap: 2px;
    margin-bottom: 20px;
}

.element {
    background-color: #ddd;
    border-radius: 4px;
    padding: 4px;
    text-align: center;
    cursor: pointer;
    transition: transform 0.2s, box-shadow 0.2s;
    position: relative;
    aspect-ratio: 1/1;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
}

.element:hover {
    transform: scale(1.05);
    box-shadow: 0 5px 15px rgba(0,0,0,0.2);
    z-index: 10;
}

.atomic-number {
    font-size: 10px;
    text-align: left;
}

.symbol {
    font-size: 16px;
    font-weight: bold;
}

.name {
    font-size: 8px;
    overflow: hidden;
    text-overflow: ellipsis;
}

.mass {
    font-size: 8px;
}

/* Element Categories */
.alkali-metal { background-color: #ff6666; }
.alkaline-earth { background-color: #ffdaa2; }
.transition-metal { background-color: #ffc0c0; }
.post-transition { background-color: #cccccc; }
.metalloid { background-color: #cccc99; }
.nonmetal { background-color: #a1ffa1; }
.halogen { background-color: #ffff99; }
.noble-gas { background-color: #c0ffff; }
.lanthanide { background-color: #ffbfff; }
.actinide { background-color: #ff99cc; }

/* Empty grid spaces */
.empty {
    visibility: hidden;
}

/* Modal styles */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0,0,0,0.7);
    z-index: 100;
    justify-content: center;
    align-items: center;
}

.modal-content {
    background-color: white;
    padding: 20px;
    border-radius: 8px;
    max-width: 500px;
    width: 90%;
    max-height: 172vh;
    overflow-y: auto;
    position: relative;
}

.close-button {
    position: absolute;
    top: 10px;
    right: 10px;
    font-size: 24px;
    cursor: pointer;
}

.element-details {
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.detail-header {
    display: flex;
    align-items: center;
    gap: 20px;
}

.detail-symbol {
    width: 80px;
    height: 80px;
    display: flex;
    justify-content: center;
    align-items: center;
    border-radius: 8px;
    font-size: 32px;
    font-weight: bold;
}

.detail-name h2 {
    font-size: 24px;
    margin-bottom: 5px;
}

.detail-name p {
    color: #666;
}

.detail-properties {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 10px;
}

.property {
    padding: 8px;
    background-color: #f5f5f5;
    border-radius: 4px;
}

.property-name {
    font-weight: bold;
    margin-bottom: 4px;
    font-size: 14px;
}

.property-value {
    font-size: 14px;
}

.lanthanide-row, .actinide-row {
    margin-top: 20px;
}

@media (max-width: 768px) {
    .periodic-table {
        grid-template-columns: repeat(9, 1fr);
    }
    
    .detail-properties {
        grid-template-columns: 1fr;
    }
}
/* ........................................ */



.legend {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-bottom: 20px;
    justify-content: center;
}

.legend-item {
    display: flex;
    align-items: center;
    margin-right: 10px;
}

.legend-color {
    width: 20px;
    height: 20px;
    border-radius: 4px;
    margin-right: 5px;
}

@media (max-width: 768px) {
    .periodic-table {
        grid-template-columns: repeat(9, 1fr);
    }
    
    .detail-properties {
        grid-template-columns: 1fr;
    }
}