:root {
    --primary: #4361ee;
    --secondary: #3a0ca3;
    --background: #f8f9fa;
    --card-bg: #ffffff;
    --text: #212529;
    --text-light: #6c757d;
    --transition: all 0.3s ease;
    --border-radius: 8px;
    --box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    --box-shadow-hover: 0 8px 15px rgba(0, 0, 0, 0.1);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

body {
    background-color: var(--background);
    color: var(--text);
    line-height: 1.6;
    padding: 20px;
}

.container {
    max-width: 1400px;
    margin: 0 auto;
}

header {
    text-align: center;
    margin-bottom: 30px;
}

h1 {
    font-size: 2.5rem;
    color: var(--secondary);
}

.subtitle {
    color: var(--text-light);
    font-size: 1.1rem;
}

.search-container {
    display: flex;
    justify-content: center;
    margin-bottom: 30px;
    gap: 10px;
}

#search {
    padding: 12px 20px;
    width: 300px;
    border: 2px solid #ddd;
    border-radius: var(--border-radius);
    font-size: 1rem;
    transition: var(--transition);
}

#search:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(67, 97, 238, 0.2);
}

.filter-container {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 10px;
    margin-bottom: 30px;
}

.filter-btn {
    padding: 8px 16px;
    background-color: var(--card-bg);
    border: 1px solid #ddd;
    border-radius: 20px;
    cursor: pointer;
    transition: var(--transition);
    font-weight: 500;
}

.filter-btn:hover, .filter-btn.active {
    background-color: var(--primary);
    color: white;
    border-color: var(--primary);
}

.periodic-table {
    display: grid;
    grid-template-columns: repeat(18, 1fr);
    gap: 5px;
    margin-bottom: 20px;
}

.element {
    background-color: var(--card-bg);
    border-radius: var(--border-radius);
    padding: 10px 5px;
    text-align: center;
    cursor: pointer;
    transition: var(--transition);
    box-shadow: var(--box-shadow);
    position: relative;
    overflow: hidden;
}

.element:hover {
    transform: translateY(-5px);
    box-shadow: var(--box-shadow-hover);
    z-index: 10;
}

.element .number {
    font-size: 0.7rem;
    color: var(--text-light);
    margin-bottom: 2px;
}

.element .symbol {
    font-size: 1.2rem;
    font-weight: bold;
    margin-bottom: 2px;
}

.element .name {
    font-size: 0.6rem;
    color: var(--text-light);
}

.element-details {
    display: none;
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    background-color: var(--card-bg);
    padding: 30px;
    border-radius: var(--border-radius);
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.2);
    z-index: 100;
    width: 90%;
    max-width: 600px;
    max-height: 90vh;
    overflow-y: auto;
}

.element-details.active {
    display: block;
}

.close-btn {
    position: absolute;
    top: 15px;
    right: 15px;
    font-size: 1.5rem;
    cursor: pointer;
    background: none;
    border: none;
    color: var(--text-light);
}

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

.detail-symbol {
    font-size: 3rem;
    font-weight: bold;
    margin-right: 20px;
    width: 80px;
    height: 80px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    color: white;
}

.detail-name {
    font-size: 1.8rem;
    margin-bottom: 5px;
}

.detail-number {
    color: var(--text-light);
    font-size: 1.2rem;
}

.detail-body {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 20px;
}

.detail-section h3 {
    margin-bottom: 10px;
    color: var(--secondary);
    border-bottom: 2px solid var(--secondary);
    padding-bottom: 5px;
}

.property {
    display: flex;
    justify-content: space-between;
    margin-bottom: 8px;
}

.property-name {
    font-weight: 500;
    color: var(--text-light);
}

.property-value {
    font-weight: 600;
}

.legend {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 15px;
    margin-bottom: 30px;
}

.legend-item {
    display: flex;
    align-items: center;
    gap: 5px;
}

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

.footer {
    text-align: center;
    color: var(--text-light);
    font-size: 0.9rem;
}

.overlay {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    z-index: 50;
}

.overlay.active {
    display: block;
}

.empty-space {
    visibility: hidden;
}

@media (max-width: 1200px) {
    .periodic-table {
        grid-template-columns: repeat(9, 1fr);
    }
}

@media (max-width: 768px) {
    .periodic-table {
        grid-template-columns: repeat(5, 1fr);
    }

    .detail-body {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    .periodic-table {
        grid-template-columns: repeat(3, 1fr);
    }

    .search-container {
        flex-direction: column;
        align-items: center;
    }

    #search {
        width: 100%;
    }
}

/* Category colors */
.alkali-metal { background-color: #FF9AA2; }
.alkaline-earth { background-color: #FFB7B2; }
.transition-metal { background-color: #FFDAC1; }
.post-transition-metal { background-color: #E2F0CB; }
.metalloid { background-color: #B5EAD7; }
.nonmetal { background-color: #C7CEEA; }
.halogen { background-color: #A2D7D8; }
.noble-gas { background-color: #B5EAD7; }
.lanthanide { background-color: #F8C8DC; }
.actinide { background-color: #D8BFD8; }
.unknown { background-color: #E0E0E0; }

/* Detail card category colors */
.detail-alkali-metal { background-color: #FF9AA2; }
.detail-alkaline-earth { background-color: #FFB7B2; }
.detail-transition-metal { background-color: #FFDAC1; }
.detail-post-transition-metal { background-color: #E2F0CB; }
.detail-metalloid { background-color: #B5EAD7; }
.detail-nonmetal { background-color: #C7CEEA; }
.detail-halogen { background-color: #A2D7D8; }
.detail-noble-gas { background-color: #B5EAD7; }
.detail-lanthanide { background-color: #F8C8DC; }
.detail-actinide { background-color: #D8BFD8; }
.detail-unknown { background-color: #E0E0E0; }