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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: #333;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
}

header {
    background: rgba(255, 255, 255, 0.95);
    padding: 2rem;
    text-align: center;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

header h1 {
    color: #2c3e50;
    margin-bottom: 0.5rem;
    font-size: 2.5rem;
}

header p {
    color: #7f8c8d;
    font-size: 1.1rem;
}

.controls {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 1rem;
    padding: 2rem;
    background: rgba(255, 255, 255, 0.9);
    margin: 2rem auto;
    max-width: 1200px;
    border-radius: 10px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.1);
}

.filter-btn {
    padding: 0.9rem 1.7rem;
    border: none;
    border-radius: 30px;
    background: linear-gradient(145deg, #ffffff, #ecf0f1);
    color: #2c3e50;
    box-shadow: 0 4px 10px rgba(0,0,0,0.15);
    cursor: pointer;
    transition: all 0.25s ease;
    font-size: 1rem;
    font-weight: 600;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.filter-btn:hover {
    background: #bdc3c7;
    transform: translateY(-2px);
    box-shadow: 0 4px 10px rgba(0,0,0,0.15);
}

.filter-btn.active {
    background: linear-gradient(145deg, #3498db, #2980b9);
    color: white;
    box-shadow: 0 6px 15px rgba(0,0,0,0.35);
    transform: scale(0.95);
}

.periodic-table-container {
    overflow-x: auto;
    padding: 1rem;
    max-width: 100%;
}

.periodic-table {
    display: grid;
    grid-template-columns: 40px repeat(18, minmax(50px, 1fr));
    grid-template-rows: 40px repeat(8, minmax(50px, 1fr));
    gap: 4px;
    margin: 0 auto;
    padding: 2rem;
    background: rgba(255, 255, 255, 0.95);
    border-radius: 15px;
    box-shadow: 0 8px 25px rgba(0,0,0,0.2);
    min-width: min-content;
}

.group-label, .period-label {
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: bold;
    color: #2c3e50;
    background: rgba(236, 240, 241, 0.8);
    border-radius: 4px;
}

.group-label {
    grid-row: 1;
}

.period-label {
    grid-column: 1;
}

.element {
    aspect-ratio: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 0.5rem;
    cursor: pointer;
    border: 2px solid transparent;
    position: relative;
    min-width: 50px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.15);
    transition: all 0.25s ease;
    border-radius: 12px;
    font-weight: 600;
    background: linear-gradient(145deg, rgba(255,255,255,0.95), rgba(245,245,245,0.9));
}

.element:hover {
    z-index: 100;
    transform: translateY(-4px) scale(1.1);
    box-shadow: 0 6px 18px rgba(0,0,0,0.25);
}

.element.hidden {
    display: none;
}

.element.empty {
    background: transparent;
    border: none;
    cursor: default;
}

.element.empty:hover {
    transform: none;
    box-shadow: none;
}

.element .element-symbol {
    font-size: 1.2rem;
    font-weight: bold;
    margin-bottom: 0.2rem;
}

.element-number {
    font-size: 0.8rem;
    opacity: 0.8;
}

/* Colors pels blocs */
.bloc-s { background: #ff6b6b; color: white; }
.bloc-p { background: #48dbfb; color: white; }
.bloc-d { background: #1dd1a1; color: white; }
.bloc-f { background: #f368e0; color: white; }

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

.element-modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0,0,0,0.8);
    z-index: 1000;
    overflow-y: auto;
}

.modal-content {
    background: rgb(255, 255, 255);
    margin: 2rem auto;
    padding: 2rem;
    border-radius: 15px;
    max-width: 800px;
    position: relative;
    animation: modalFadeZoom 0.4s ease forwards;
    box-shadow: 0 10px 30px rgba(0,0,0,0.3);
}

.close-btn {
    position: absolute;
    top: 1rem;
    right: 1.5rem;
    font-size: 2rem;
    cursor: pointer;
    color: #7f8c8d;
    transition: color 0.2s ease;
}

.close-btn:hover {
    color: #e74c3c;
}

.element-header {
    display: flex;
    align-items: center;
    gap: 2rem;
    margin-bottom: 2rem;
    padding-bottom: 1rem;
    border-bottom: 2px solid #ecf0f1;
}

.element-header h2 {
    color: #2c3e50;
    font-size: 2.5rem;
}

.element-header .element-symbol {
    font-size: 3rem;
    padding: 1rem;
    border-radius: 10px;
    min-width: 80px;
    text-align: center;
    font-weight: bold;
}

.element-details {
    display: grid;
    gap: 2rem;
}

.info-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1rem;
}

.info-item {
    display: flex;
    justify-content: space-between;
    padding: 0.5rem 0;
    border-bottom: 1px solid #ecf0f1;
}

.label {
    font-weight: 600;
    color: #2c3e50;
}

.basic-info, .applications, .curiosities, .discovery, .physical-properties, .electronic-properties {
    background: #f8f9fa;
    padding: 1.5rem;
    border-radius: 10px;
    border-left: 4px solid #3498db;
}

.basic-info h3, .applications h3, .curiosities h3, .discovery h3, .physical-properties h3, .electronic-properties h3 {
    color: #3498db;
    margin-bottom: 1rem;
}

.applications ul, .curiosities ul {
    list-style: none;
    padding-left: 0;
}

.applications li, .curiosities li {
    padding: 0.5rem 0;
    border-bottom: 1px solid #e9ecef;
    position: relative;
    padding-left: 1.5rem;
}

.applications li::before {
    content: '🔬';
    position: absolute;
    left: 0;
}

.curiosities li::before {
    content: '💡';
    position: absolute;
    left: 0;
}

.applications li:last-child, .curiosities li:last-child {
    border-bottom: none;
}

.properties-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
}

footer {
    background: #2c3e50;
    color: white;
    text-align: center;
    padding: 2rem;
    margin-top: 2rem;
}

/* Interactivitat */
@media (max-width: 1200px) {
    .periodic-table {
        grid-template-columns: 35px repeat(18, minmax(45px, 1fr));
    }
}

@media (max-width: 768px) {
    .periodic-table {
        grid-template-columns: 30px repeat(18, minmax(40px, 1fr));
        gap: 2px;
        padding: 1rem;
    }
    
    .element .element-symbol {
        font-size: 0.9rem;
    }
    
    .element-number {
        font-size: 0.6rem;
    }
    
    .modal-content {
        margin: 1rem;
        padding: 1rem;
    }
    
    .element-header {
        flex-direction: column;
        gap: 1rem;
        text-align: center;
    }
    
    .info-grid, .properties-grid {
        grid-template-columns: 1fr;
    }
    
    .controls {
        flex-direction: column;
        align-items: center;
    }
}

@media (max-width: 480px) {
    .periodic-table {
        grid-template-columns: 25px repeat(18, minmax(35px, 1fr));
    }
    
    .element {
        padding: 0.25rem;
    }
    
    .element .element-symbol {
        font-size: 0.8rem;
    }
    
    .element-number {
        font-size: 0.5rem;
    }
    
    header h1 {
        font-size: 2rem;
    }
}