:root {
    --primary: #0f172a;
    --secondary: #2563eb;
    --text: #1f2933;
    --muted: #6b7280;
    --bg: #f9fafb;
    --card: #ffffff;
    --border: #e5e7eb;
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Inter, Helvetica, Arial, sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.7;
    display: flex;
    flex-direction: column;
    align-items: center;
}

ol, ul{
    margin: 1.5rem 0;
    padding-left: 20px;
}

.banner {
    width: 100%;
    color: var(---colorOnSecondary);
    padding: 2.5rem 1.5rem;
    margin: 20px;
    margin-top: calc(var(--header-height) + 4rem);
    max-width: 1100px;
}

.banner h1 {
    margin: 0 0 0.5rem 0;
    font-size: 2rem;
}

.banner p {
    margin: 0;
    color: var(---textColor);
    font-size: 0.95rem;
}

main {
      max-width: 1100px;
      margin: 0 auto;
      padding: 14px;
      display: grid;
      grid-template-columns: 280px 1fr;
      gap: 2rem;
}

nav {
    background: var(--card);
    border: 1px solid var(--border);
    border-radius: 14px;
    padding: 1.25rem;
    position: sticky;
    top: 1.5rem;
    height: fit-content;
}

nav h2 {
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--muted);
    margin: 0 0 0.75rem 0;
}

nav ul {
    list-style: none;
    padding: 0;
    margin: 0;
}

nav li {
    margin-bottom: 0.5rem;
}

nav a {
    text-decoration: none;
    font-size: 0.9rem;
    color: var(--secondary);
}

nav a:hover {
    text-decoration: underline;
}

section {
    background: var(--card);
    border: 1px solid var(--border);
    border-radius: 16px;
    padding: 2rem;
    margin-bottom: 1.5rem;
}

section h2 {
    margin-top: 0;
    font-size: 1.4rem;
    color: var(--primary);
}

section h3 {
    margin-bottom: 0.25rem;
    font-size: 1.05rem;
    color: var(--primary);
}

ul {
    padding-left: 1.25rem;
}

footer {
    border-top: 1px solid var(--border);
    padding: 2rem 1.5rem;
    text-align: center;
    color: var(--muted);
    font-size: 0.85rem;
    background: #fff;
}

@media (max-width: 900px) {
    main {
    grid-template-columns: 1fr;
    padding: 2rem 1.5rem 4rem;
    }

    nav {
    position: relative;
    top: 0;
    }
}