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

body {
    font-family: 'Segoe UI', system-ui, sans-serif;
    background-color: #0a1810; /* Very dark green-black */
    color: #d4f0e2;
    line-height: 1.65;
}

.container {
    display: flex;
    min-height: 100vh;
}

.sidebar {
    width: 260px;
    background-color: #11251a; /* Dark forest green */
    padding: 2rem 1.5rem;
    position: sticky;
    top: 0;
    height: 100vh;
    overflow-y: auto;
}

.toc-nav ul {
    list-style: none;
}

.toc-nav a {
    display: block;
    color: #a3e4c9;
    text-decoration: none;
    padding: 0.9rem 0;
    font-weight: 500;
    transition: color 0.2s;
}

.toc-nav a:hover,
.toc-nav a:focus {
    color: #4ade80;
}

main {
    flex: 1;
    max-width: 860px;
    margin: 0 auto;
    padding: 2.5rem 2rem;
}

header {
    text-align: center;
    padding: 4rem 0 2.5rem;
}

h1 {
    color: #4ade80; /* Vibrant green accent */
    font-size: 2.8rem;
    margin-bottom: 0.6rem;
}

.subtitle {
    color: #a3e4c9;
    font-size: 1.25rem;
}

section {
    margin-bottom: 3.5rem;
}

h2 {
    color: #4ade80;
    font-size: 2.1rem;
    margin: 2.2rem 0 1.1rem;
    border-bottom: 2px solid #1e3a2f;
    padding-bottom: 0.7rem;
}

a {
    color: #4ade80;
    text-decoration: none;
}

a:hover {
    text-decoration: underline;
}

ul, ol {
    padding-left: 1.9rem;
    margin: 1.2rem 0;
}

footer {
    text-align: center;
    padding: 2.5rem 1rem;
    background: #11251a;
    color: #a3e4c9;
    font-size: 0.95rem;
}

/* Mobile responsive */
@media (max-width: 992px) {
    .container {
        flex-direction: column;
    }
    
    .sidebar {
        position: relative;
        width: 100%;
        height: auto;
        padding: 1.2rem;
    }
    
    main {
        padding: 1.5rem;
    }
    
    header {
        padding: 2.5rem 0 1.8rem;
    }
    
    h1 {
        font-size: 2.3rem;
    }
}