body {
        margin: 0;
        padding: 0;
        font-family: Arial, Helvetica, sans-serif;
        background: #f8fafc;
        color: #111827;
        line-height: 1.8;
    }

    .page {
        max-width: 1000px;
        margin: 0 auto;
        padding: 20px;
    }

    .hero,
    .content-box,
    .formula-box,
    .example-box,
    .faq-box,
    .video-box,
    .related-box {
        background: #ffffff;
        border: 1px solid #dbe4ee;
        border-radius: 12px;
        box-shadow: 0 4px 14px rgba(15, 23, 42, 0.05);
        padding: 18px;
        margin-bottom: 20px;
    }

    h1 {
        margin: 0 0 10px 0;
        font-size: clamp(1.7rem, 3vw, 2.5rem);
        line-height: 1.2;
        text-align: center;
        color: #0f172a;
    }

    h2 {
        margin: 0 0 12px 0;
        font-size: 1.3rem;
        color: #0f172a;
    }

    h3 {
        margin: 18px 0 10px 0;
        font-size: 1.05rem;
        color: #0f172a;
    }

    p {
        margin: 0 0 14px 0;
    }

    ul, ol {
        margin: 0 0 14px 22px;
    }

    .intro {
        max-width: 900px;
        margin: 0 auto;
    }

    .formula {
        background: #f59e0b;
        border-left: 4px solid #0f62fe;
        padding: 12px 14px;
        border-radius: 8px;
        font-weight: 600;
        margin: 10px 0 14px 0;
    }

    .note {
        font-size: 0.95rem;
        color: #475569;
    }

    .video-box {
        text-align: center;
    }

    .video-box iframe {
        width: 100%;
        max-width: 560px;
        aspect-ratio: 9 / 16;
        height: auto;
        border: 0;
        border-radius: 12px;
        background: #000;
    }

    #back {
        margin-top: 14px;
    }

    #back a {
        display: inline-block;
        padding: 10px 16px;
        border-radius: 999px;
        border: 2px solid #000;
        background: #1e88b3;
        color: #fff;
        text-decoration: none;
        font-weight: 900;
        text-shadow: 2px 2px 2px #000;
            
    }

    #back a:hover {
        background: #f59e0b;
        color: #fff;
        zoom: 105%; 
    }

    .related-links {
        list-style: none;
        padding: 0;
        margin: 0;
        display: flex;
        flex-wrap: wrap;
        gap: 12px;
    }

    .related-links li {
        list-style: none;
    }

    .related-links a {
        display: inline-block;
        padding: 10px 14px;
        border-radius: 999px;
        background: #1e88b3;
        color: #fff;
        text-decoration: none;
        font-weight: 900;       
        text-shadow: 2px 2px 2px #000;
        border: 2px solid #000;
    }

    .related-links a:hover {
        background: #f59e0b;
        color: #fff;
        zoom: 105%; 
    }

    .table-wrap {
        overflow-x: auto;
    }

    table {
        width: 100%;
        border-collapse: collapse;
        margin: 12px 0 0 0;
    }

    th, td {
        border: 1px solid #cbd5e1;
        padding: 10px;
        text-align: left;
        vertical-align: top;
    }

    th {
        background: #1e88b3;
        color: #fff;
        text-shadow: 2px 2px 2px #000;
    }

    .small {
        font-size: 0.95rem;
        color: #334155;
    }

    @media (max-width: 767px) {
        .page {
            padding: 14px;
        }

        .hero,
        .content-box,
        .faq-box,
        .formula-box,
        .example-box,
        .video-box,
        .related-box {
            padding: 16px;
        }

        ul, ol {
            margin-left: 18px;
        }
    }