:root {
            --primary: #48b6e9;
            --primary-soft: rgba(72, 182, 233, 0.1);
            --primary-dark: #2da1d7;
            --shadow: 0 12px 40px rgba(0, 0, 0, 0.08);
            --shadow-hover: 0 20px 48px rgba(72, 182, 233, 0.15);
            --radius: 14px;
            --bg-light: #ffffff;
            --bg-gray: #f5f5f7;
            --text-dark: #1d1d1f;
            --text-muted: #86868b;
        }

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

        body {
            font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
            line-height: 1.7;
            color: var(--text-dark);
            background-color: var(--bg-light);
            overflow-x: hidden;
        }

        /* Root Sheath */
        .sheath {
            display: flex;
            flex-direction: column;
            min-height: 100vh;
        }

        /* Header Crest & Ribbon */
        .crest {
            position: fixed;
            top: 0;
            left: 0;
            right: 0;
            z-index: 1000;
            background: rgba(255, 255, 255, 0.85);
            backdrop-filter: blur(20px);
            -webkit-backdrop-filter: blur(20px);
            border-bottom: 1px solid rgba(0, 0, 0, 0.05);
        }
        .ribbon {
            display: flex;
            flex-wrap: wrap;
            align-items: center;
            justify-content: space-between;
            max-width: 1200px;
            margin: 0 auto;
            padding: 0 24px;
            height: 64px;
        }
        .seal {
            display: flex;
            align-items: center;
            height: 100%;
        }
        .seal img {
            height: 28px;
            width: auto;
        }
        .scroll {
            display: flex;
            flex-wrap: wrap;
            align-items: center;
        }
        .guide {
            display: inline-flex;
            align-items: center;
            padding: 0 16px;
            height: 64px;
            color: var(--text-dark);
            text-decoration: none;
            font-size: 14px;
            font-weight: 500;
            transition: color 0.25s ease;
            position: relative;
        }
        .guide:hover {
            color: var(--primary);
        }
        .guide.active {
            color: var(--primary);
            font-weight: 600;
        }
        .guide.active::after {
            content: '';
            position: absolute;
            bottom: 0;
            left: 16px;
            right: 16px;
            height: 3px;
            background-color: var(--primary);
            border-radius: 3px 3px 0 0;
        }

        /* Main Jacket */
        .jacket {
            margin-top: 64px;
            flex-grow: 1;
        }

        /* Article 1: Hero Cover */
        .cover {
            position: relative;
            min-height: 85vh;
            display: flex;
            align-items: center;
            background: linear-gradient(135deg, #f5f7fa 0%, #e4efff 100%);
            padding: 80px 24px;
            overflow: hidden;
        }
        .cover::before {
            content: '';
            position: absolute;
            top: 0;
            right: 0;
            width: 50%;
            height: 100%;
            background: linear-gradient(135deg, rgba(72, 182, 233, 0.03) 0%, rgba(72, 182, 233, 0.12) 100%);
            clip-path: polygon(100% 0, 0% 100%, 100% 100%);
        }
        .cover-canvas {
            max-width: 1200px;
            margin: 0 auto;
            width: 100%;
            display: flex;
            flex-wrap: wrap;
            align-items: center;
            justify-content: space-between;
            position: relative;
            z-index: 2;
        }
        .cover-prose {
            flex: 1.1;
            min-width: 320px;
            padding-right: 48px;
        }
        .cover-illustration {
            flex: 0.9;
            min-width: 320px;
            display: flex;
            justify-content: center;
            align-items: center;
        }
        .illustration-sheath {
            position: relative;
            width: 100%;
            max-width: 480px;
            height: auto;
        }

        /* Headings */
        .topic-folder {
            font-size: clamp(32px, 5vw, 64px);
            line-height: 1.15;
            font-weight: 800;
            letter-spacing: -0.02em;
            color: var(--text-dark);
            margin-bottom: 20px;
            word-break: keep-all;
        }
        .topic-folder span {
            color: var(--primary);
            display: block;
        }
        .prose-folder {
            font-size: clamp(16px, 2vw, 18px);
            color: var(--text-muted);
            line-height: 1.8;
            margin-bottom: 40px;
            max-width: 540px;
            word-break: keep-all;
        }

        /* Stamps */
        .stamp-batch {
            display: flex;
            flex-wrap: wrap;
            gap: 16px;
        }
        .stamp-primary {
            background: var(--primary);
            color: #ffffff;
            padding: 16px 36px;
            border-radius: 50px;
            font-weight: 600;
            font-size: 16px;
            text-decoration: none;
            box-shadow: 0 10px 30px rgba(72, 182, 233, 0.3);
            border: 1px solid transparent;
            transition: all 0.25s ease;
            display: inline-flex;
            align-items: center;
            justify-content: center;
        }
        .stamp-primary:hover {
            background: var(--primary-dark);
            transform: translateY(-2px);
            box-shadow: 0 12px 36px rgba(72, 182, 233, 0.4);
        }
        .stamp-secondary {
            background: rgba(255, 255, 255, 0.85);
            color: var(--text-dark);
            padding: 16px 36px;
            border-radius: 50px;
            font-weight: 600;
            font-size: 16px;
            text-decoration: none;
            border: 1px solid rgba(0, 0, 0, 0.1);
            transition: all 0.25s ease;
            display: inline-flex;
            align-items: center;
            justify-content: center;
        }
        .stamp-secondary:hover {
            background: #ffffff;
            border-color: var(--primary);
            color: var(--primary);
            transform: translateY(-2px);
        }

        /* Aside: Academic Tools */
        .spread {
            background: var(--bg-light);
            padding: 100px 24px;
        }
        .spread-jacket {
            max-width: 1200px;
            margin: 0 auto;
        }
        .topic-spread {
            font-size: clamp(28px, 4vw, 40px);
            font-weight: 800;
            text-align: center;
            margin-bottom: 16px;
            color: var(--text-dark);
        }
        .prose-spread {
            text-align: center;
            color: var(--text-muted);
            max-width: 600px;
            margin: 0 auto 60px auto;
            font-size: 16px;
        }
        .batch-spread {
            display: flex;
            flex-wrap: wrap;
            gap: 30px;
        }
        .memo-spread {
            flex: 1;
            min-width: 280px;
            background: #ffffff;
            padding: 40px 30px;
            border-radius: var(--radius);
            border: 1px solid #d2d2d7;
            transition: all 0.25s ease;
            position: relative;
            overflow: hidden;
        }
        .memo-spread:hover {
            transform: translateY(-8px);
            border-color: var(--primary);
            box-shadow: var(--shadow-hover);
        }
        .glyph-spread {
            width: 60px;
            height: 60px;
            border-radius: 12px;
            background: var(--primary-soft);
            color: var(--primary);
            display: flex;
            align-items: center;
            justify-content: center;
            margin-bottom: 24px;
        }
        .topic-memo {
            font-size: 20px;
            font-weight: 700;
            margin-bottom: 14px;
            color: var(--text-dark);
        }
        .prose-memo {
            font-size: 15px;
            color: var(--text-muted);
            line-height: 1.6;
        }

        /* Div: Brainstorming layout */
        .canvas {
            background: var(--bg-gray);
            padding: 100px 24px;
        }
        .canvas-jacket {
            max-width: 1200px;
            margin: 0 auto;
            display: flex;
            flex-wrap: wrap;
            align-items: center;
            gap: 60px;
        }
        .canvas-prose {
            flex: 1;
            min-width: 320px;
        }
        .canvas-illustration {
            flex: 1.2;
            min-width: 320px;
            background: #ffffff;
            border-radius: var(--radius);
            border: 1px solid #d2d2d7;
            padding: 40px;
            box-shadow: var(--shadow);
        }
        .topic-canvas {
            font-size: clamp(28px, 4vw, 40px);
            font-weight: 800;
            color: var(--text-dark);
            margin-bottom: 20px;
        }
        .prose-canvas {
            color: var(--text-muted);
            font-size: 16px;
            line-height: 1.8;
            margin-bottom: 30px;
        }
        .folio-canvas {
            display: flex;
            flex-direction: column;
            gap: 20px;
        }
        .bullet-canvas {
            display: flex;
            align-items: flex-start;
            gap: 16px;
        }
        .bullet-glyph {
            width: 24px;
            height: 24px;
            border-radius: 50%;
            background: var(--primary-soft);
            color: var(--primary);
            display: flex;
            align-items: center;
            justify-content: center;
            flex-shrink: 0;
            margin-top: 3px;
        }
        .bullet-prose {
            font-size: 15px;
            color: var(--text-dark);
        }
        .bullet-prose strong {
            display: block;
            font-size: 16px;
            margin-bottom: 4px;
            color: var(--text-dark);
        }

        /* Article 2: Student Discount */
        .spread-acquire {
            padding: 100px 24px;
            background: linear-gradient(180deg, var(--bg-light) 0%, #e9f5fc 100%);
        }
        .acquire-jacket {
            max-width: 1000px;
            margin: 0 auto;
            text-align: center;
        }
        .topic-acquire {
            font-size: clamp(28px, 4vw, 40px);
            font-weight: 800;
            color: var(--text-dark);
            margin-bottom: 16px;
        }
        .prose-acquire {
            color: var(--text-muted);
            font-size: 16px;
            max-width: 600px;
            margin: 0 auto 60px auto;
        }
        .batch-acquire {
            display: flex;
            flex-wrap: wrap;
            gap: 30px;
            margin-bottom: 50px;
            justify-content: center;
        }
        .folio-acquire {
            flex: 1;
            min-width: 260px;
            background: rgba(255, 255, 255, 0.95);
            border: 1px solid rgba(72, 182, 233, 0.2);
            border-radius: var(--radius);
            padding: 35px 30px;
            position: relative;
            box-shadow: 0 8px 30px rgba(0,0,0,0.04);
            transition: all 0.25s ease;
        }
        .folio-acquire:hover {
            transform: translateY(-5px);
            box-shadow: 0 15px 35px rgba(72, 182, 233, 0.12);
            border-color: var(--primary);
        }
        .acquire-step {
            position: absolute;
            top: -20px;
            left: 50%;
            transform: translateX(-50%);
            width: 40px;
            height: 40px;
            border-radius: 50%;
            background: var(--primary);
            color: #ffffff;
            font-weight: 800;
            font-size: 18px;
            display: flex;
            align-items: center;
            justify-content: center;
            box-shadow: 0 4px 10px rgba(72, 182, 233, 0.4);
        }
        .acquire-topic {
            font-size: 18px;
            font-weight: 700;
            margin: 15px 0 12px 0;
            color: var(--text-dark);
        }
        .acquire-prose {
            font-size: 14px;
            color: var(--text-muted);
            line-height: 1.6;
        }

        /* Footer Endnote */
        .endnote {
            background: #111112;
            color: #e5e5e7;
            padding: 80px 24px 40px 24px;
            border-top: 1px solid #222223;
        }
        .bind-endnote {
            max-width: 1200px;
            margin: 0 auto;
            display: flex;
            flex-wrap: wrap;
            justify-content: space-between;
            border-bottom: 1px solid #222223;
            padding-bottom: 40px;
            gap: 40px;
        }
        .margin-endnote {
            flex: 1;
            min-width: 200px;
        }
        .margin-topic {
            font-size: 16px;
            font-weight: 600;
            margin-bottom: 20px;
            color: #ffffff;
        }
        .margin-prose {
            font-size: 14px;
            color: #86868b;
            line-height: 1.8;
            margin-bottom: 15px;
        }
        .margin-knot {
            display: block;
            color: #86868b;
            text-decoration: none;
            font-size: 14px;
            margin-bottom: 10px;
            transition: color 0.25s ease;
        }
        .margin-knot:hover {
            color: var(--primary);
        }
        
        .tail {
            max-width: 1200px;
            margin: 0 auto;
            padding-top: 30px;
            display: flex;
            flex-wrap: wrap;
            justify-content: space-between;
            align-items: center;
            font-size: 13px;
            color: #86868b;
            gap: 20px;
        }

        /* Responsive Design */
        @media (max-width: 1024px) {
            .cover-canvas {
                flex-direction: column;
                text-align: center;
            }
            .cover-prose {
                padding-right: 0;
                margin-bottom: 50px;
                display: flex;
                flex-direction: column;
                align-items: center;
            }
            .cover-illustration {
                width: 100%;
            }
            .cover {
                min-height: auto;
                padding-top: 120px;
            }
            .prose-folder {
                margin-left: auto;
                margin-right: auto;
            }
            .stamp-batch {
                justify-content: center;
            }
        }

        @media (max-width: 768px) {
            .batch-spread {
                flex-direction: column;
            }
            .canvas-jacket {
                flex-direction: column;
            }
            .batch-acquire {
                flex-direction: column;
                gap: 40px;
            }
            .crest {
                position: relative;
            }
            .jacket {
                margin-top: 0;
            }
            .ribbon {
                height: auto;
                padding: 12px 16px;
                justify-content: center;
                gap: 12px;
            }
            .scroll {
                justify-content: center;
                width: 100%;
            }
            .guide {
                height: auto;
                padding: 8px 12px;
                font-size: 13px;
            }
            .guide.active::after {
                display: none;
            }
        }

.ribbon-crest {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    line-height: 1.7;
    word-break: break-word;
    color: var(--deep);
}
.ribbon-crest,
.ribbon-crest *,
.ribbon-crest *::before,
.ribbon-crest *::after {
    box-sizing: border-box;
}

.ribbon-crest [role="navigation"],
.ribbon-crest div,
.ribbon-crest section,
.ribbon-crest article,
.ribbon-crest aside,
.ribbon-crest p,
.ribbon-crest h1,
.ribbon-crest h2,
.ribbon-crest h3,
.ribbon-crest h4,
.ribbon-crest h5,
.ribbon-crest h6,
.ribbon-crest a {
    margin: 0;
    padding: 0;
    font: inherit;
    color: inherit;
    letter-spacing: inherit;
    line-height: inherit;
}

.ribbon-crest p,
.ribbon-crest h1,
.ribbon-crest h2,
.ribbon-crest h3,
.ribbon-crest h4,
.ribbon-crest h5,
.ribbon-crest h6 {
    text-decoration: none;
}

.ribbon-crest img {
    display: block;
    max-width: 100%;
    height: auto;
    border: 0;
}

.ribbon-crest {
    box-shadow: none;
    filter: none;
    text-shadow: none;
    background-image: none;
    border-top: none;
    border-left: none;
    border-right: none;
    outline: none;
}

.ribbon-crest a.ribbon-guide {
    --aisite-shell-nav-padding: 0;
    --aisite-shell-nav-margin: 0;
    --aisite-shell-nav-line-height: normal;
    --aisite-shell-nav-display: inline;
    --aisite-shell-nav-height: auto;
    --aisite-shell-nav-min-height: auto;
}

.ribbon-crest a.ribbon-guide,
.ribbon-crest a.ribbon-guide:hover,
.ribbon-crest a.ribbon-guide:focus,
.ribbon-crest a.ribbon-guide:active,
.ribbon-crest a.ribbon-guide.active,
.ribbon-crest a.ribbon-guide[aria-current="page"] {
    background: transparent;
    border: none;
    border-bottom: none;
    box-shadow: none;
    outline: none;
    text-decoration: none;
    padding: var(--aisite-shell-nav-padding, 0);
    margin: var(--aisite-shell-nav-margin, 0);
    line-height: var(--aisite-shell-nav-line-height, normal);
    display: var(--aisite-shell-nav-display, inline);
    height: var(--aisite-shell-nav-height, auto);
    min-height: var(--aisite-shell-nav-min-height, auto);
}

.ribbon-crest{
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            z-index: 1000;
            background: rgba(255, 255, 255, 0.85);
            backdrop-filter: blur(20px);
            border-bottom: 1px solid rgba(0,0,0,0.05);
        }

.ribbon-crest .ribbon-ribbon{
            max-width: 1400px;
            margin: 0 auto;
            padding: 0 30px;
            height: 64px;
            display: flex;
            align-items: center;
            justify-content: space-between;
            flex-wrap: wrap;
        }

.ribbon-crest .ribbon-seal{
            height: 32px;
            display: flex;
            align-items: center;
        }

.ribbon-crest .ribbon-seal img{
            height: 100%;
            display: block;
        }

.ribbon-crest .ribbon-scroll{
            display: flex;
            gap: 32px;
            list-style: none;
            flex-wrap: wrap;
        }

.ribbon-crest .ribbon-guide{
            text-decoration: none;
            color: #424245;
            font-size: 14px;
            font-weight: 500;
            transition: color 0.25s ease;
            position: relative;
        }

.ribbon-crest .ribbon-guide:hover{
            color: #48b6e9;
        }

.ribbon-crest .ribbon-guide.active{
            color: #48b6e9;
        }

.ribbon-crest .ribbon-guide.active::after{
            content: '';
            position: absolute;
            bottom: -22px;
            left: 0;
            width: 100%;
            height: 2px;
            background: #48b6e9;
        }

@media (max-width: 768px){.ribbon-crest .ribbon-ribbon{ height: auto; padding: 15px; flex-direction: column; gap: 15px; }

.ribbon-crest .ribbon-scroll{ justify-content: center; gap: 15px; }}

.ribbon-crest {
    background: rgb(255, 255, 255);
    background-image: none;
}

.endnote-tail {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    line-height: 1.7;
    word-break: break-word;
    color: var(--deep);
}
.endnote-tail,
.endnote-tail *,
.endnote-tail *::before,
.endnote-tail *::after {
    box-sizing: border-box;
}

.endnote-tail [role="navigation"],
.endnote-tail div,
.endnote-tail section,
.endnote-tail article,
.endnote-tail aside,
.endnote-tail p,
.endnote-tail h1,
.endnote-tail h2,
.endnote-tail h3,
.endnote-tail h4,
.endnote-tail h5,
.endnote-tail h6,
.endnote-tail a {
    margin: 0;
    padding: 0;
    font: inherit;
    color: inherit;
    letter-spacing: inherit;
    line-height: inherit;
}

.endnote-tail p,
.endnote-tail h1,
.endnote-tail h2,
.endnote-tail h3,
.endnote-tail h4,
.endnote-tail h5,
.endnote-tail h6 {
    text-decoration: none;
}

.endnote-tail img {
    display: block;
    max-width: 100%;
    height: auto;
    border: 0;
}

.endnote-tail {
    box-shadow: none;
    filter: none;
    text-shadow: none;
    background-image: none;
    border-top: none;
    border-left: none;
    border-right: none;
    outline: none;
}

.endnote-tail a,
.endnote-tail a:hover,
.endnote-tail a:focus,
.endnote-tail a:active {
    background: transparent;
    box-shadow: none;
    outline: none;
    text-decoration: none;
}

.endnote-tail{
            background: #f5f5f7;
            padding: 80px 0 40px;
            border-top: 1px solid #d2d2d7;
        }

.endnote-tail .endnote-endnote{
            max-width: 1400px;
            margin: 0 auto;
            padding: 0 30px;
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
            gap: 40px;
        }

.endnote-tail .endnote-margin-topic{
            font-weight: 700;
            font-size: 16px;
            margin-bottom: 24px;
            color: #1d1d1f;
        }

.endnote-tail .endnote-bind-links{
            list-style: none;
            display: flex;
            flex-direction: column;
            gap: 12px;
        }

.endnote-tail .endnote-knot-tail{
            text-decoration: none;
            color: #424245;
            font-size: 14px;
            transition: color 0.25s ease;
        }

.endnote-tail .endnote-knot-tail:hover{
            color: #48b6e9;
        }

.endnote-tail .endnote-tail-bottom{
            grid-column: 1 / -1;
            display: flex;
            justify-content: space-between;
            align-items: center;
            font-size: 13px;
            color: #86868b;
            flex-wrap: wrap;
            gap: 20px;
        }