:root {
    --primary-color: #0056b3;
    --text-color: #333333;
    --bg-color: #f9f9f9;
    --card-bg: #ffffff;
    --border-color: #dddddd;
    --highlight-bg: #f1f8ff;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--bg-color);
    margin: 0;
    padding: 0;
}

header {
    background-color: var(--primary-color);
    color: white;
    padding: 2rem 1rem;
    text-align: center;
}

header h1 {
    margin: 0 0 0.5rem 0;
    font-size: 2.2rem;
}

header p {
    margin: 0;
    font-size: 1.1rem;
    opacity: 0.9;
}

/* Top Navigation Bar */
nav.navbar {
    background-color: #ffffff;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: center;
    gap: 2rem;
    padding: 0.75rem 1rem;
    position: sticky;
    top: 0;
    z-index: 100;
}

nav.navbar a {
    color: var(--text-color);
    text-decoration: none;
    font-weight: 600;
    font-size: 0.95rem;
}

nav.navbar a.active, nav.navbar a:hover {
    color: var(--primary-color);
}

.container {
    max-width: 950px;
    margin: 2rem auto;
    padding: 0 1rem;
}

section {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    padding: 1.8rem;
    margin-bottom: 1.5rem;
    box-shadow: 0 2px 4px rgba(0,0,0,0.02);
}

h2 {
    color: var(--primary-color);
    margin-top: 0;
    border-bottom: 2px solid var(--border-color);
    padding-bottom: 0.5rem;
}

h3 {
    color: #333;
    margin-top: 1.2rem;
}

ul, ol {
    padding-left: 1.5rem;
}

table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 1rem;
}

th, td {
    border: 1px solid var(--border-color);
    padding: 0.75rem;
    text-align: left;
    font-size: 0.95rem;
}

th {
    background-color: #f1f1f1;
}

.callout {
    background-color: var(--highlight-bg);
    border-left: 4px solid var(--primary-color);
    padding: 1rem;
    margin: 1rem 0;
    border-radius: 0 4px 4px 0;
}

footer {
    text-align: center;
    padding: 2rem;
    font-size: 0.9rem;
    color: #666;
}

a {
    color: var(--primary-color);
    text-decoration: none;
}

a:hover {
    text-decoration: underline;
}