/* --- THEME COLORS --- */
    :root {
        --primary-color: #077c8c;
        --primary-dark: #056674;
        --text-dark: #2c3e50;
        --bg-white: #ffffff;
        --scroll-padding: 100px;
    }

    html { scroll-behavior: smooth; }

    body {
        font-family: 'Merriweather', serif; 
        color: var(--text-dark);
        line-height: 1.8;
        background-color: #f9f9f9;
    }

    h1, h2, h3, h4, h5 { font-family: 'Poppins', sans-serif; font-weight: 700; }
    a { text-decoration: none; color: var(--primary-color); transition: 0.3s; }
    a:hover { color: var(--primary-dark); }

    /* --- HERO SECTION --- */
    .blog-hero-section {
        position: relative;
        width: 100%;
        height: 55vh;
        min-height: 400px;
        background-size: cover;
        background-position: center;
        display: flex;
        align-items: flex-end;
        color: white;
        margin-bottom: 50px;
    }

    .blog-hero-overlay {
        position: absolute;
        top: 0; left: 0; right: 0; bottom: 0;
        background: linear-gradient(to bottom, rgba(0,0,0,0.3) 0%, rgba(0,0,0,0.85) 100%);
        z-index: 1;
    }

    .blog-hero-content {
        position: relative;
        z-index: 2;
        padding-bottom: 50px;
    }

    .hero-category {
        background-color: var(--primary-color);
        color: white;
        padding: 5px 15px;
        border-radius: 50px;
        font-size: 0.85rem;
        text-transform: uppercase;
        font-family: 'Poppins', sans-serif;
        letter-spacing: 1px;
        display: inline-block;
        margin-bottom: 15px;
    }

    .hero-title {
        font-size: 2.8rem;
        line-height: 1.2;
        margin-bottom: 20px;
        text-shadow: 0 2px 4px rgba(0,0,0,0.3);
    }

    .hero-meta img {
        width: 40px; height: 40px; border-radius: 50%; border: 2px solid white; margin-right: 10px;
    }

    /* --- CONTENT & SIDEBAR GRID --- */
    .article-body h2 {
        margin-top: 40px;
        margin-bottom: 20px;
        font-size: 1.8rem;
        color: var(--primary-dark);
        border-left: 5px solid var(--primary-color);
        padding-left: 15px;
        scroll-margin-top: var(--scroll-padding);
    }

    .content-section { margin-bottom: 30px; }

    /* --- STICKY SIDEBAR (TOC) --- */
    .sticky-sidebar {
        position: -webkit-sticky;
        position: sticky;
        top: 20px;
        background: #fff;
        padding: 25px;
        border-radius: 12px;
        border: 1px solid #eee;
        box-shadow: 0 5px 20px rgba(0,0,0,0.03);
    }

    .toc-header {
        font-size: 1.1rem;
        font-weight: 700;
        margin-bottom: 15px;
        color: var(--text-dark);
        border-bottom: 2px solid #f0f0f0;
        padding-bottom: 10px;
    }

    .toc-list { list-style: none; padding: 0; margin: 0; }
    .toc-list li { margin-bottom: 12px; }

    .toc-link {
        font-family: 'Poppins', sans-serif;
        font-size: 0.9rem;
        color: #555;
        display: block;
        padding-left: 10px;
        border-left: 3px solid transparent;
        transition: all 0.2s;
    }

    .toc-link:hover, .toc-link.active {
        color: var(--primary-color);
        border-left: 3px solid var(--primary-color);
        font-weight: 600;
        background: #f4fbfc;
    }

    @media (max-width: 991px) {
        .sticky-sidebar { position: relative; margin-bottom: 40px; top: 0; }
    }