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

body {
    background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
    min-height: 100vh;
    padding: 30px;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    background-color: rgba(255, 255, 255, 0.95);
    border-radius: 16px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    overflow: hidden;
    padding: 30px;
}

header {
    text-align: center;
    padding: 30px 0;
    border-bottom: 1px solid #eaeaea;
    margin-bottom: 30px;
    background: linear-gradient(135deg, #6a11cb 0%, #2575fc 100%);
    margin: -30px -30px 30px -30px;
    color: white;
    padding: 40px 20px;
}



h1 {
    font-size: 2.8rem;
    margin-bottom: 15px;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
}

.subtitle {
    font-size: 1.2rem;
    opacity: 0.9;
    max-width: 700px;
    margin: 0 auto;
}

.upload-area {
    background-color: #f8f9fc;
    border: 3px dashed #6a85b6;
    border-radius: 12px;
    padding: 40px;
    text-align: center;
    margin-bottom: 50px;
    transition: all 0.3s ease;
}



.upload-area.drag-over {
    background-color: #e1e8ff;
    border-color: #2575fc;
    transform: scale(1.01);
}

.upload-area h2 {
    color: #3a506b;
    margin-bottom: 20px;
}

.file-input-wrapper {
    position: relative;
    display: inline-block;
    margin: 20px 0;
}

.file-input {
    position: absolute;
    left: 0;
    top: 0;
    opacity: 0;
    width: 100%;
    height: 100%;
    cursor: pointer;
}

.file-label {
    display: inline-block;
    padding: 15px 35px;
    background: linear-gradient(135deg, #2575fc 0%, #6a11cb 100%);
    color: white;
    border-radius: 50px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px rgba(37, 117, 252, 0.3);
}

.file-label:hover {
    transform: translateY(-3px);
    box-shadow: 0 7px 20px rgba(37, 117, 252, 0.4);
}

.file-label:active {
    transform: translateY(1px);
}

.file-types {
    color: #6c757d;
    font-size: 0.95rem;
    margin-top: 15px;
}

.stats-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 20px;
    margin-bottom: 30px;
}

.stat-card {
    background: white;
    border-radius: 12px;
    padding: 25px 20px;
    text-align: center;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.05);
    border-top: 4px solid #2575fc;
    transition: transform 0.3s ease;
}

.stat-card:hover {
    transform: translateY(-5px);
}

.stat-title {
    font-size: 1rem;
    color: #6c757d;
    margin-bottom: 10px;
}

.stat-value {
    font-size: 2.5rem;
    font-weight: 700;
    color: #3a506b;
}

.charts-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(500px, 1fr));
    gap: 30px;
    margin-top: 20px;
}

.chart-wrapper {
    background: white;
    border-radius: 12px;
    padding: 25px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.05);
}

.chart-title {
    text-align: center;
    margin-bottom: 25px;
    font-size: 1.4rem;
    color: #3a506b;
    position: relative;
}

.chart-title::after {
    content: '';
    display: block;
    width: 60px;
    height: 3px;
    background: linear-gradient(135deg, #2575fc 0%, #6a11cb 100%);
    margin: 10px auto 0;
    border-radius: 2px;
}

.chart-container {
    position: relative;
    height: 300px;
    width: 100%;
}

.loading {
    display: none;
    text-align: center;
    padding: 40px;
}

.spinner {
    border: 4px solid rgba(0, 0, 0, 0.1);
    width: 36px;
    height: 36px;
    border-radius: 50%;
    border-left-color: #2575fc;
    animation: spin 1s linear infinite;
    margin: 0 auto 20px;
}

@keyframes spin {
    to {
        transform: rotate(360deg);
    }
}

.sample-data-btn {
    background: #e9ecef;
    border: none;
    color: #6c757d;
    padding: 8px 20px;
    border-radius: 4px;
    cursor: pointer;
    margin-top: 15px;
    transition: all 0.2s;
}

.sample-data-btn:hover {
    background: #dee2e6;
}

@media (max-width: 768px) {
    .charts-container {
        grid-template-columns: 1fr;
    }
    
    .container {
        padding: 20px;
    }
    
    h1 {
        font-size: 2.2rem;
    }
}

@media (max-width: 480px) {
    .upload-area {
        padding: 25px 15px;
    }
    
    .charts-container {
        grid-template-columns: 1fr;
    }
    
    .stat-value {
        font-size: 2rem;
    }
}