/* Base styles */
:root {
    --primary-color: #2c3e50;
    --secondary-color: #3498db;
    --accent-color: #e74c3c;
    --background-color: #f5f7fa;
    --text-color: #333;
    --border-color: #ddd;
}

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

body {
    font-family: 'Helvetica Neue', Arial, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--background-color);
    padding: 0;
    margin: 0;
}

/* Header styles */
header {
    background-color: var(--primary-color);
    color: white;
    padding: 1rem;
    text-align: center;
}

header h1 {
    margin: 0;
    font-size: 1.8rem;
}

.back-link {
    display: inline-block;
    margin-top: 0.5rem;
    color: white;
    text-decoration: none;
    font-size: 0.9rem;
}

.back-link:hover {
    text-decoration: underline;
}

/* Navigation styles */
nav {
    background-color: var(--secondary-color);
    padding: 0.5rem;
}

nav ul {
    list-style: none;
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 0.5rem;
}

nav li {
    margin: 0.25rem;
}

nav a {
    color: white;
    text-decoration: none;
    padding: 0.5rem 1rem;
    border-radius: 4px;
    display: inline-block;
    transition: background-color 0.3s;
}

nav a:hover {
    background-color: rgba(255, 255, 255, 0.2);
}

/* Main content styles */
main {
    padding: 1rem;
    max-width: 1200px;
    margin: 0 auto;
}

.intro {
    text-align: center;
    margin: 2rem 0;
}

.intro h2 {
    color: var(--primary-color);
    margin-bottom: 1rem;
}

/* Table styles */
.table-container {
    overflow-x: auto;
    margin: 1rem 0;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
    border-radius: 5px;
}

table {
    width: 100%;
    border-collapse: collapse;
    background-color: white;
}

th, td {
    padding: 0.75rem;
    text-align: left;
    border: 1px solid var(--border-color);
}

th {
    background-color: var(--primary-color);
    color: white;
    font-weight: bold;
}

tr:nth-child(even) {
    background-color: #f2f2f2;
}

/* Empty cells styling */
td:empty {
    background-color: #f9f9f9;
}

/* Footer styles */
footer {
    background-color: var(--primary-color);
    color: white;
    text-align: center;
    padding: 1rem;
    margin-top: 2rem;
}

/* Responsive adjustments */
@media (max-width: 768px) {
    header h1 {
        font-size: 1.5rem;
    }
    
    nav ul {
        flex-direction: column;
        align-items: center;
    }
    
    nav a {
        width: 100%;
        text-align: center;
    }
    
    th, td {
        padding: 0.5rem;
        font-size: 0.9rem;
    }
}

/* Print styles */
@media print {
    nav, .back-link {
        display: none;
    }
    
    body, table {
        font-size: 10pt;
    }
    
    .table-container {
        box-shadow: none;
    }
    
    table {
        border: 1px solid #000;
    }
    
    th, td {
        border: 1px solid #000;
    }
}