:root {
    --primary-color: #2c3e50;
    --secondary-color: #3498db;
    --background-color: #f5f6fa;
    --text-color: #2c3e50;
    --border-radius: 8px;
    --spacing: 20px;
}

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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    background-color: var(--background-color);
    color: var(--text-color);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: var(--spacing);
}

header {
    text-align: center;
    margin-bottom: calc(var(--spacing) * 2);
}

h1 {
    color: var(--primary-color);
    margin-bottom: var(--spacing);
}

section {
    background: white;
    padding: var(--spacing);
    border-radius: var(--border-radius);
    margin-bottom: var(--spacing);
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
}

.form-group {
    margin-bottom: var(--spacing);
}

label {
    display: block;
    margin-bottom: 5px;
    font-weight: bold;
}

select, input {
    width: 100%;
    padding: 8px;
    border: 1px solid #ddd;
    border-radius: 4px;
    font-size: 16px;
}

button {
    background-color: var(--secondary-color);
    color: white;
    padding: 10px 20px;
    border: none;
    border-radius: var(--border-radius);
    cursor: pointer;
    font-size: 16px;
    transition: background-color 0.3s ease;
}

button:hover {
    background-color: #2980b9;
}

.hidden {
    display: none;
}

.feedback-buttons {
    display: flex;
    gap: var(--spacing);
    justify-content: center;
    margin-top: var(--spacing);
}

.feedback-btn {
    flex: 1;
    max-width: 150px;
}

.charts-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing);
    margin-top: var(--spacing);
}

.chart {
    background: white;
    padding: var(--spacing);
    border-radius: var(--border-radius);
    min-height: 300px;
}

@media (max-width: 768px) {
    .container {
        padding: 10px;
    }
    
    .feedback-buttons {
        flex-direction: column;
        align-items: center;
    }
    
    .feedback-btn {
        width: 100%;
        max-width: 100%;
    }
}