.ns-toc {
        background: #F0FBF6;
        border: 1.5px solid #007A3D;
        border-radius: 10px;
        padding: 0;
        margin: 24px 0;
        overflow: hidden;
        font-size: .9rem;
    }
    .ns-toc__header {
        display: flex;
        align-items: center;
        justify-content: space-between;
        padding: 12px 16px;
        background: #007A3D;
        cursor: pointer;
    }
    .ns-toc__title {
        font-family: 'Syne', sans-serif;
        font-size: .88rem;
        font-weight: 700;
        color: #fff;
    }
    .ns-toc__toggle {
        background: rgba(255,255,255,.2);
        border: none;
        border-radius: 50%;
        width: 26px;
        height: 26px;
        display: flex;
        align-items: center;
        justify-content: center;
        cursor: pointer;
        color: #fff;
        transition: transform .25s ease, background .2s;
        flex-shrink: 0;
    }
    .ns-toc__toggle:hover { background: rgba(255,255,255,.3); }
    .ns-toc__toggle.collapsed { transform: rotate(-90deg); }
    .ns-toc__list {
        list-style: none;
        padding: 12px 16px 14px;
        margin: 0;
        counter-reset: none;
        display: flex;
        flex-direction: column;
        gap: 2px;
        transition: max-height .3s ease, opacity .25s ease;
        max-height: 600px;
        opacity: 1;
        overflow: hidden;
    }
    .ns-toc__list.hidden {
        max-height: 0;
        opacity: 0;
        padding-top: 0;
        padding-bottom: 0;
    }
    .ns-toc__item { margin: 0; }
    .ns-toc__item--sub { padding-left: 20px; }
    .ns-toc__link {
        display: flex;
        align-items: baseline;
        gap: 8px;
        padding: 5px 6px;
        border-radius: 6px;
        color: #065F46;
        font-size: .87rem;
        line-height: 1.45;
        text-decoration: none;
        transition: background .15s, color .15s;
    }
    .ns-toc__link:hover { background: rgba(0,122,61,.1); color: #007A3D; text-decoration: none; }
    .ns-toc__link.active { background: rgba(0,122,61,.15); color: #007A3D; font-weight: 700; }
    .ns-toc__num {
        background: #007A3D;
        color: #fff;
        font-size: .7rem;
        font-weight: 800;
        width: 20px;
        height: 20px;
        border-radius: 50%;
        display: flex;
        align-items: center;
        justify-content: center;
        flex-shrink: 0;
        font-family: 'Syne', sans-serif;
    }
    .ns-toc__dash { color: #9CA3AF; font-size: .8rem; flex-shrink: 0; }
    @media (max-width: 480px) {
        .ns-toc__list { max-height: 300px; overflow-y: auto; }
    }
    /* Reading highlight: heading in viewport */
    .article-body h2:target, .article-body h3:target {
        color: #007A3D;
        scroll-margin-top: 130px;
    }