/*
 * The shell every competency page wears: page frame plus the one-row header.
 *
 * The four activity pages had byte-identical 43-line <style> blocks, and the
 * multiplication control panel repeated the same prefix — so a header change
 * meant five edits, and page six would have been a copy of page five. One file
 * instead: pages now differ only in the activity they host.
 */

body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 20px;
    background-color: #f5f5f5;
}

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

/* Title and back link share one row: the activity below needs the vertical
   space more than a stacked header and a subtitle do. */
.page-header {
    display: flex;
    align-items: center;
    gap: 16px;
    margin-bottom: 16px;
}

.page-header h1 {
    margin: 0;
    color: #333;
    font-size: 24px;
}

.back-link {
    display: inline-block;
    flex: 0 0 auto;
    padding: 10px 20px;
    background-color: #4CAF50;
    color: white;
    text-decoration: none;
    border-radius: 4px;
    transition: background-color 0.3s;
}

.back-link:hover {
    background-color: #45a049;
}