:root {
    --primary-color: #4a6fa5;
    --secondary-color: #166088;
    --accent-color: #4fc3f7;
    --dark-color: #1a2639;
    --light-color: #f0f4f8;
    --success-color: #4caf50;
    --warning-color: #ff9800;
    --danger-color: #f44336;
    --text-color: #333;
    --text-light: #666;
    --border-radius: 8px;
    --box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    --transition: all 0.3s ease;
}

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

body {
    font-family: 'Poppins', sans-serif;
    background-color: #f5f7fa;
    color: var(--text-color);
    line-height: 1.6;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
}

header {
    text-align: center;
    margin-bottom: 30px;
    padding: 20px 0;
}

header h1 {
    font-size: 2.5rem;
    color: var(--dark-color);
    margin-bottom: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
}

header p {
    font-size: 1.1rem;
    color: var(--text-light);
}

.search-container {
    margin-bottom: 30px;
    background: white;
    padding: 20px;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
}

.search-box {
    position: relative;
    display: flex;
    align-items: center;
    margin-bottom: 20px;
}

.search-box i {
    position: absolute;
    left: 15px;
    color: var(--text-light);
}

.search-box input {
    width: 100%;
    padding: 12px 20px 12px 45px;
    border: 1px solid #ddd;
    border-radius: var(--border-radius);
    font-size: 1rem;
    transition: var(--transition);
}

.search-box input:focus {
    outline: none;
    border-color: var(--accent-color);
    box-shadow: 0 0 0 2px rgba(79, 195, 247, 0.2);
}

.search-box button {
    position: absolute;
    right: 10px;
    background: none;
    border: none;
    color: var(--text-light);
    cursor: pointer;
    padding: 5px;
    display: none;
}

.search-box button.active {
    display: block;
}

.filter-controls {
    display: flex;
    flex-wrap: wrap;
    gap: 15px;
    align-items: center;
}

.category-filter, .state-filter {
    display: flex;
    align-items: center;
    gap: 10px;
}

.category-filter label, .state-filter span {
    font-weight: 500;
    color: var(--text-light);
}

.category-filter select {
    padding: 8px 12px;
    border: 1px solid #ddd;
    border-radius: var(--border-radius);
    background: white;
    font-family: inherit;
    cursor: pointer;
}

.state-filter {
    margin-left: auto;
}

.state-btn {
    padding: 6px 12px;
    border: 1px solid #ddd;
    background: white;
    border-radius: 20px;
    cursor: pointer;
    font-size: 0.9rem;
    transition: var(--transition);
}

.state-btn:hover {
    background: #f0f0f0;
}

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

.elements-list {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 15px;
    margin-bottom: 30px;
}

.element-card {
    background: white;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    padding: 15px;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 15px;
}

.element-card:hover {
    transform: translateY(-3px);
    box-shadow: 0 6px 16px rgba(0, 0, 0, 0.1);
}

.element-symbol-container {
    width: 50px;
    height: 50px;
    border-radius: var(--border-radius);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    color: white;
    font-weight: bold;
    flex-shrink: 0;
}

.element-symbol {
    font-size: 1.3rem;
}

.element-number {
    font-size: 0.7rem;
    opacity: 0.9;
}

.element-info {
    flex-grow: 1;
}

.element-name {
    font-weight: 600;
    margin-bottom: 3px;
}

.element-category {
    font-size: 0.85rem;
    color: var(--text-light);
    margin-bottom: 5px;
}

.element-state {
    display: inline-block;
    padding: 2px 8px;
    border-radius: 12px;
    font-size: 0.75rem;
    background: #f0f0f0;
    color: var(--text-color);
}

/* Element category colors */
.alkali { background-color: #f44336; }
.alkaline { background-color: #ff9800; }
.transition { background-color: #ffeb3b; color: #333; }
.basic { background-color: #4caf50; }
.semimetal { background-color: #8bc34a; }
.nonmetal { background-color: #2196f3; }
.halogen { background-color: #9c27b0; }
.noble { background-color: #673ab7; }
.lanthanide { background-color: #00bcd4; }
.actinide { background-color: #009688; }

/* Modal styles */
.element-modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    opacity: 0;
    visibility: hidden;
    transition: var(--transition);
}

.element-modal.active {
    opacity: 1;
    visibility: visible;
}

.modal-content {
    background: white;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    width: 90%;
    max-width: 600px;
    max-height: 90vh;
    overflow-y: auto;
    transform: scale(0.8);
    transition: var(--transition);
    position: relative;
}

.element-modal.active .modal-content {
    transform: scale(1);
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
    padding: 20px 20px 15px;
    border-bottom: 1px solid #eee;
}

.modal-header h2 {
    font-size: 1.8rem;
    color: var(--dark-color);
}

.modal-header button {
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--text-light);
    transition: var(--transition);
}

.modal-header button:hover {
    color: var(--danger-color);
}

.modal-body {
    padding: 0 20px 20px;
}

.element-basic-info {
    display: flex;
    gap: 20px;
    margin-bottom: 20px;
    align-items: center;
}

.element-symbol-box {
    position: relative;
    width: 80px;
    height: 80px;
    border-radius: 8px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    color: white;
    flex-shrink: 0;
}

.element-symbol-box .element-symbol {
    font-size: 2.5rem;
    font-weight: 700;
}

.element-symbol-box .element-number {
    position: absolute;
    top: 5px;
    left: 5px;
    font-size: 0.8rem;
}

.element-stats {
    flex-grow: 1;
}

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

.stat-label {
    font-weight: 500;
    color: var(--text-light);
}

.element-description {
    margin-bottom: 20px;
    line-height: 1.6;
    color: var(--text-color);
}

.element-properties {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 15px;
}

.property {
    background: #f9f9f9;
    padding: 15px;
    border-radius: var(--border-radius);
}

.property h3 {
    font-size: 1rem;
    margin-bottom: 10px;
    color: var(--primary-color);
}

.property p {
    font-size: 0.9rem;
    color: var(--text-light);
}

footer {
    text-align: center;
    padding: 20px;
    color: var(--text-light);
    font-size: 0.9rem;
}

footer i {
    color: var(--danger-color);
}

/* Responsive styles */
@media (max-width: 768px) {
    header h1 {
        font-size: 2rem;
    }

    .filter-controls {
        flex-direction: column;
        align-items: flex-start;
    }

    .state-filter {
        margin-left: 0;
    }

    .elements-list {
        grid-template-columns: 1fr;
    }

    .element-properties {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 576px) {
    .container {
        padding: 10px;
    }

    header {
        padding: 10px 0;
    }

    .search-container {
        padding: 15px;
    }

    .modal-content {
        width: 95%;
    }
}

/* Animation for element selection */
@keyframes cardPop {
    0% { transform: scale(1); }
    50% { transform: scale(1.05); }
    100% { transform: scale(1); }
}

.element-selected {
    animation: cardPop 0.3s ease;
}

/* Modal animation */
@keyframes modalFadeIn {
    from {
        opacity: 0;
        transform: translateY(-20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes modalContentScale {
    from {
        transform: scale(0.9);
    }
    to {
        transform: scale(1);
    }
}