:root {
    --primary-color: #007bff;
    --secondary-color: #6c757d;
    --background-color: #f8f9fa;
    --text-color: #343a40;
    --card-bg: #ffffff;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    line-height: 1.6;
    background-color: var(--background-color);
    color: var(--text-color);
    padding: 20px;
}

.container {
    max-width: 800px;
    margin: 0 auto;
    padding: 2rem;
    background: var(--card-bg);
    border-radius: 8px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
}

header {
    text-align: center;
    margin-bottom: 2rem;
    border-bottom: 1px solid #eee;
    padding-bottom: 1rem;
}

h1 {
    color: var(--primary-color);
    margin-bottom: 0.5rem;
}

.card {
    background: #f1f3f5;
    padding: 1.5rem;
    border-radius: 6px;
    margin-bottom: 2rem;
    text-align: center;
}

.hidden {
    display: none;
    margin-top: 1rem;
    color: green;
    font-weight: bold;
}

button {
    background-color: var(--primary-color);
    color: white;
    border: none;
    padding: 0.5rem 1rem;
    font-size: 1rem;
    border-radius: 4px;
    cursor: pointer;
    transition: background-color 0.3s;
}

button:hover {
    background-color: #0056b3;
}

.features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1.5rem;
    margin-top: 2rem;
}

.feature-item {
    padding: 1rem;
    border: 1px solid #ddd;
    border-radius: 4px;
    text-align: center;
}

.feature-item h3 {
    color: var(--secondary-color);
    margin-bottom: 0.5rem;
}

footer {
    text-align: center;
    margin-top: 2rem;
    font-size: 0.8rem;
    color: var(--secondary-color);
}