:root {
            --bg: #eef3f8;
            --card: #ffffff;
            --text: #1d2733;
            --muted: #5a6a7b;
            --line: #d8e1ea;
            --accent: #315b86;
            --accent2: #4f86c6;
            --shadow: 0 10px 30px rgba(0,0,0,0.08);
        }

        * {
            box-sizing: border-box;
        }

        body {
            margin: 0;
            font-family: "Segoe UI", Arial, sans-serif;
            background: linear-gradient(180deg, #f4f8fc 0%, #e7eef6 100%);
            color: var(--text);
            line-height: 1.65;
        }

        header {
            background: linear-gradient(135deg, #24486d 0%, #4f86c6 100%);
            color: #fff;
            padding: 30px 20px 24px 20px;
            box-shadow: var(--shadow);
        }

        .wrap {
            width: 100%;
            max-width: 1200px;
            margin: 0 auto;
        }

        h1 {
            margin: 0 0 10px 0;
            font-size: 34px;
            line-height: 1.2;
        }

        .subtitle {
            font-size: 17px;
            opacity: 0.95;
            max-width: 980px;
        }

        main {
            padding: 24px 16px 40px 16px;
        }

        .layout {
            display: grid;
            grid-template-columns: 300px 1fr;
            gap: 20px;
            align-items: start;
        }

        .toc, .panel {
            background: var(--card);
            border: 1px solid var(--line);
            border-radius: 16px;
            box-shadow: var(--shadow);
        }

        .toc {
            position: sticky;
            top: 18px;
            padding: 18px;
        }

        .toc h2 {
            margin-top: 0;
            font-size: 20px;
            color: var(--accent);
        }

        .toc a {
            display: block;
            text-decoration: none;
            color: var(--text);
            padding: 7px 10px;
            border-radius: 10px;
            margin-bottom: 4px;
            transition: 0.18s ease;
            font-size: 14px;
        }

        .toc a:hover {
            background: #edf5ff;
            color: var(--accent);
        }

        .panel {
            padding: 24px;
        }

        section {
            border-bottom: 1px solid var(--line);
            padding-bottom: 22px;
            margin-bottom: 22px;
        }

        section:last-child {
            border-bottom: none;
            margin-bottom: 0;
            padding-bottom: 0;
        }

        h2.sec-title {
            margin: 0 0 14px 0;
            color: var(--accent);
            font-size: 24px;
        }

        p {
            margin: 0 0 12px 0;
        }

        .hero-box {
            background: linear-gradient(135deg, #f6fbff 0%, #ebf4ff 100%);
            border: 1px solid #cfe1f6;
            border-radius: 14px;
            padding: 16px 18px;
            margin-bottom: 24px;
        }

        .flow {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(170px, 1fr));
            gap: 10px;
            margin-top: 14px;
        }

        .step {
            background: #f9fbfd;
            border: 1px solid var(--line);
            border-radius: 12px;
            padding: 12px;
            font-size: 14px;
            text-align: center;
            font-weight: 600;
        }

        .footer-note {
            margin-top: 24px;
            padding: 16px 18px;
            border-radius: 14px;
            background: #f6f9fc;
            border: 1px solid var(--line);
            color: var(--muted);
        }

        .top-link {
            display: inline-block;
            margin-top: 10px;
            text-decoration: none;
            color: var(--accent2);
            font-weight: 600;
        }

        @media (max-width: 900px) {
            .layout {
                grid-template-columns: 1fr;
            }

            .toc {
                position: static;
            }

            h1 {
                font-size: 28px;
            }
        }