*{margin:0;padding:0;box-sizing:border-box}
        :root{
            --bg:#fff;--text:#333;--muted:#999;--light:#b5b5b5;--line:#e5e5e5;--dark:#1a1a1a;
            --blue:#2a6cb6;--blue-bg:#f0f5fb;
            --teal:#1a7a5a;--teal-bg:#edf7f2;
            --amber:#8a5a10;--amber-bg:#fdf5e6;
            --coral:#a04020;--coral-bg:#fdf0eb
        }
        ::selection{background:#d5d5d5;color:var(--dark)}
        html{-webkit-text-size-adjust:100%;scroll-behavior:smooth}
        body{font-family:'Source Serif 4',Georgia,serif;background:var(--bg);color:var(--text);line-height:1.75;font-size:17px;-webkit-font-smoothing:antialiased}
        .layout{display:flex;min-height:100vh;max-width:1060px;margin:0 auto;padding:56px 32px 56px 0}
        nav{position:sticky;top:56px;align-self:flex-start;min-width:150px;padding:0 36px 0 32px;text-align:right}
        nav a{display:block;font-family:'Inter',sans-serif;font-size:14px;color:var(--muted);text-decoration:none;padding:4px 0;transition:color .2s}
        nav a:hover{color:var(--dark)}
        nav a.active{color:var(--dark);font-weight:500;text-decoration:underline;text-underline-offset:4px;text-decoration-thickness:1px}
        .divider{width:1px;background:var(--line);flex-shrink:0}
        main{flex:1;padding-left:48px;max-width:700px}
        .page-label{font-family:'Inter',sans-serif;font-size:13px;color:var(--light);margin-bottom:2px}
        .page-name{font-size:22px;font-weight:400;color:var(--dark);margin-bottom:28px}
        h2{font-size:17px;font-weight:600;color:var(--dark);margin:36px 0 12px}
        p{margin-bottom:16px;line-height:1.8}

        .formula-row{display:grid;grid-template-columns:1fr 1fr;gap:8px;margin:18px 0}
        .formula-block{background:var(--blue-bg);border-left:3px solid var(--blue);padding:14px 18px}
        .formula-block .f-label{font-family:'Inter',sans-serif;font-size:10px;text-transform:uppercase;letter-spacing:.08em;color:var(--blue);margin-bottom:6px}
        .formula-block .f-expr{font-family:'Source Serif 4',serif;font-style:italic;font-size:15px;color:var(--dark);line-height:1.8}
        .formula-block .f-note{font-family:'Inter',sans-serif;font-size:11px;color:var(--muted);margin-top:6px;line-height:1.5}
        .f-var{color:var(--blue);font-style:italic}

        .key-point{border-left:3px solid var(--teal);padding:10px 16px;margin:20px 0;font-size:15px;background:var(--teal-bg);color:#0f4a36;font-family:'Inter',sans-serif;line-height:1.6}

        .module-box{border:1px solid var(--line);margin:32px 0}
        .module-header{padding:14px 18px;border-bottom:1px solid var(--line);background:#fafafa;display:flex;align-items:center;justify-content:space-between;flex-wrap:wrap;gap:8px}
        .module-title-inner{font-family:'Inter',sans-serif;font-size:12px;font-weight:600;color:var(--dark);text-transform:uppercase;letter-spacing:.06em}
        .tab-group{display:flex;gap:4px}
        .tab-btn{font-family:'Inter',sans-serif;font-size:11px;padding:4px 12px;border:1px solid var(--line);background:#fff;color:var(--muted);cursor:pointer;transition:all .15s}
        .tab-btn.active{background:var(--blue);border-color:var(--blue);color:#fff}
        .module-body-inner{padding:20px 18px}

        .ctrl-row3{display:grid;grid-template-columns:1fr 1fr 1fr;gap:10px;margin-bottom:12px}
        .ctrl-row2{display:grid;grid-template-columns:1fr 1fr;gap:12px;margin-bottom:12px}
        .ctrl-group{display:flex;flex-direction:column;gap:4px}
        .ctrl-label{font-family:'Inter',sans-serif;font-size:10px;color:var(--muted);text-transform:uppercase;letter-spacing:.06em}
        .ctrl-value{font-family:'Inter',sans-serif;font-size:12px;font-weight:600;color:var(--dark)}
        input[type=range]{width:100%;accent-color:var(--blue);height:3px;cursor:pointer}

        .reseed-btn{font-family:'Inter',sans-serif;font-size:11px;padding:4px 14px;border:1px solid var(--line);background:#fff;color:var(--muted);cursor:pointer;transition:all .15s}
        .reseed-btn:hover{background:var(--blue-bg);color:var(--blue);border-color:var(--blue)}

        .persist-badge{display:inline-block;font-family:'Inter',sans-serif;font-size:12px;font-weight:600;padding:3px 10px;border-radius:2px;margin-bottom:8px}
        .pb-ok{background:var(--teal-bg);color:var(--teal)}
        .pb-warn{background:var(--amber-bg);color:var(--amber)}
        .pb-bad{background:var(--coral-bg);color:var(--coral)}

        .canvas-wrap{background:#fafafa;border:1px solid var(--line);margin-bottom:10px}
        canvas{display:block}

        .stat-row4{display:grid;grid-template-columns:repeat(4,1fr);gap:1px;background:var(--line);border:1px solid var(--line);margin-bottom:8px}
        .sc{background:#fff;padding:8px 8px;text-align:center}
        .sc .scl{font-family:'Inter',sans-serif;font-size:9px;text-transform:uppercase;letter-spacing:.07em;color:var(--muted);margin-bottom:3px}
        .sc .scv{font-family:'Source Serif 4',serif;font-size:13px;font-weight:600;color:var(--dark)}
        .sc.hi .scv{color:var(--blue)}
        .sc.ok .scv{color:var(--teal)}
        .sc.warn .scv{color:var(--coral)}

        .leg-row{display:flex;gap:12px;margin-bottom:8px;flex-wrap:wrap}
        .leg-item{display:flex;align-items:center;gap:5px;font-family:'Inter',sans-serif;font-size:11px;color:var(--muted)}
        .leg-sw{width:22px;height:2.5px}
        .leg-sq{width:10px;height:10px;border-radius:1px;opacity:.6}

        .module-nav{display:flex;justify-content:space-between;align-items:center;margin-top:48px;padding-top:20px;border-top:1px solid var(--line)}
        .nav-prev,.nav-next{font-family:'Inter',sans-serif;font-size:13px;text-decoration:none}
        .nav-prev{color:var(--muted)}.nav-prev:hover{color:var(--dark)}
        .nav-next{color:var(--blue)}.nav-next:hover{color:var(--dark)}
        .footer{margin-top:44px;padding-top:18px;border-top:1px solid var(--line);font-family:'Inter',sans-serif;font-size:12px;color:var(--light)}

        @media(max-width:768px){
            .layout{flex-direction:column;padding:28px 20px}
            nav{position:static;text-align:left;min-width:auto;padding:0 0 24px 0;display:flex;flex-wrap:wrap;gap:3px 14px}
            nav a{display:inline}.divider{width:100%;height:1px}
            main{padding-left:0;padding-top:28px;max-width:100%}
            .ctrl-row3,.ctrl-row2{grid-template-columns:1fr 1fr}
            .stat-row4{grid-template-columns:1fr 1fr}
            .formula-row{grid-template-columns:1fr}
        }
    
        .skip-link{position:absolute;left:-9999px;top:8px;background:var(--dark);color:#fff;padding:8px 12px;z-index:10;font-family:'Inter',sans-serif}
        .skip-link:focus{left:8px}
        .learning-goals{border-left:3px solid var(--teal);background:var(--teal-bg);padding:14px 18px;margin:0 0 28px;font-family:'Inter',sans-serif;font-size:13px;line-height:1.65}
        .learning-goals strong,.assumption-note strong,.source-note strong{color:var(--dark)}
        .learning-goals ul{margin:6px 0 0 18px}
        .assumption-note{border-left:3px solid var(--amber);background:var(--amber-bg);padding:12px 16px;margin:18px 0 26px;font-family:'Inter',sans-serif;font-size:13px;line-height:1.65;color:var(--text)}
        .source-note{border-top:1px solid var(--line);padding-top:16px;margin-top:34px;font-family:'Inter',sans-serif;font-size:12px;line-height:1.65;color:var(--muted)}
        .source-note a{color:var(--blue);text-underline-offset:2px}
        canvas{max-width:100%;height:auto}
        button:focus-visible,input:focus-visible,a:focus-visible{outline:2px solid var(--blue);outline-offset:3px}
        @media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*,*::before,*::after{animation-duration:.01ms!important;animation-iteration-count:1!important;transition-duration:.01ms!important}}