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

body {
    font-family: Arial, sans-serif;
    line-height: 1.6;
    padding: 20px;
    background-color: #f4f4f4;
    margin: 0;
}

nav {
    background: #333;
    padding: 1rem;
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    display: flex;
}

nav a {
    color: white;
    text-decoration: none;
    padding: 0.5rem 1rem;
    border-radius: 4px;
    transition: background-color 0.2s;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-weight: bold;
    font-size: 1.1rem;
}

nav a:hover {
    background: #555;
}

/* Style for back button on sub-pages */
nav a[href="index.html"]:not(:only-child)::before {
    content: "←";
    font-size: 1.2em;
    line-height: 1;
}

/* Style for main page title */
nav a:only-child {
    font-size: 1.3rem;
    margin: 0 auto;
    padding: 0.5rem 0;
}

nav a:only-child:hover {
    background: transparent;
    opacity: 0.9;
}

main {
    padding: 2rem 20px;
    max-width: 1200px;
    margin: 0 auto;
}

.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
}

.feature-card {
    background: white;
    padding: 1.5rem;
    border-radius: 8px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}

.btn {
    display: inline-block;
    padding: 0.5rem 1rem;
    background: #007bff;
    color: white;
    text-decoration: none;
    border-radius: 4px;
    margin-top: 1rem;
}

.btn:hover {
    background: #0056b3;
}

h1 {
    text-align: center;
    margin-bottom: 2rem;
}

.test-result {
    padding: 1rem;
    margin: 0.5rem 0;
    border-radius: 4px;
}

.success {
    background: #d4edda;
    color: #155724;
}

.failure {
    background: #f8d7da;
    color: #721c24;
}

.visual-demo {
    margin: 1rem 0;
    padding: 1rem;
    background: white;
    border-radius: 8px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
    min-height: 200px;
    display: flex;
    justify-content: center;
    align-items: center;
}

.demo-canvas {
    border: 1px solid #ddd;
    max-width: 100%;
}

.font-sample {
    font-size: 1.2rem;
    margin: 0.5rem 0;
    padding: 0.5rem;
}

.activity-log {
    background: #f8f9fa;
    border: 1px solid #dee2e6;
    border-radius: 4px;
    padding: 1rem;
    margin: 1rem 0;
    min-height: 200px;
    max-height: 300px;
    overflow-y: auto;
}

.log-entry {
    padding: 0.5rem;
    border-bottom: 1px solid #e9ecef;
    font-family: monospace;
    white-space: pre-wrap;
}

.log-entry:first-child {
    border-left: 3px solid #28a745;
    background: #f8fff9;
}