:root{
    --bg:#eef1f1; --panel:#ffffff; --panel2:#f6f8f8;
    --ink:#15201e; --muted:#586764; --faint:#8595921a;
    --line:#d7dedc; --line2:#c4cecb;
    --land:#e2e8e6; --landline:#c2ccc9; --ocean:#e7eeee; --graticule:#00000010;
    --crude:#a8620d; --crude-soft:#a8620d22;
    --gas:#0a7c8f; --gas-soft:#0a7c8f22;
    --prod:#6b46c1; --prod-soft:#6b46c122;
    --accent:var(--crude);
    --shadow:0 1px 2px #0000000d,0 8px 24px #0000000f;
    --mono:ui-monospace,"SF Mono",SFMono-Regular,Menlo,Consolas,monospace;
    --sans:system-ui,-apple-system,"Segoe UI",Roboto,Helvetica,Arial,sans-serif;
  }
  @media (prefers-color-scheme:dark){
    :root{
      --bg:#0b1214; --panel:#111a1d; --panel2:#0e1618;
      --ink:#e7edeb; --muted:#8fa19d; --faint:#8fa19d1a;
      --line:#243133; --line2:#2e3d40;
      --land:#16211f; --landline:#2b3a3c; --ocean:#0a1113; --graticule:#ffffff0d;
      --crude:#e6aa4f; --crude-soft:#e6aa4f26;
      --gas:#37c2d6; --gas-soft:#37c2d626;
      --prod:#a78bfa; --prod-soft:#a78bfa26;
      --shadow:0 1px 2px #00000040,0 10px 30px #00000055;
    }
  }
  :root[data-theme="light"]{
    --bg:#eef1f1; --panel:#ffffff; --panel2:#f6f8f8;
    --ink:#15201e; --muted:#586764; --line:#d7dedc; --line2:#c4cecb;
    --land:#e2e8e6; --landline:#c2ccc9; --ocean:#e7eeee; --graticule:#00000010;
    --crude:#a8620d; --crude-soft:#a8620d22; --gas:#0a7c8f; --gas-soft:#0a7c8f22;
    --prod:#6b46c1; --prod-soft:#6b46c122; --faint:#8595921a;
    --shadow:0 1px 2px #0000000d,0 8px 24px #0000000f;
  }
  :root[data-theme="dark"]{
    --bg:#0b1214; --panel:#111a1d; --panel2:#0e1618;
    --ink:#e7edeb; --muted:#8fa19d; --line:#243133; --line2:#2e3d40;
    --land:#16211f; --landline:#2b3a3c; --ocean:#0a1113; --graticule:#ffffff0d;
    --crude:#e6aa4f; --crude-soft:#e6aa4f26; --gas:#37c2d6; --gas-soft:#37c2d626;
    --prod:#a78bfa; --prod-soft:#a78bfa26; --faint:#8fa19d1a;
    --shadow:0 1px 2px #00000040,0 10px 30px #00000055;
  }

  *{box-sizing:border-box}
  html,body{margin:0;height:100%;overflow-x:hidden}
  body{background:var(--bg);color:var(--ink);font-family:var(--sans);
    font-size:15px;line-height:1.5;-webkit-font-smoothing:antialiased;}
  .app{display:flex;flex-direction:column;height:100vh;min-height:100vh}

  /* ---- header ---- */
  header{display:flex;align-items:baseline;gap:16px;flex-wrap:wrap;
    padding:14px 20px;border-bottom:1px solid var(--line);background:var(--panel);}
  .brand{display:flex;flex-direction:column;gap:2px;margin-right:auto}
  .eyebrow{font-family:var(--mono);font-size:11px;letter-spacing:.16em;
    text-transform:uppercase;color:var(--muted)}
  h1{font-size:18px;font-weight:650;margin:0;letter-spacing:-.01em}
  .h1 b{color:var(--crude)} .h1 i{color:var(--gas);font-style:normal}
  .switch{display:flex;border:1px solid var(--line2);border-radius:9px;overflow:hidden;
    font-family:var(--mono);font-size:12px}
  .switch button{appearance:none;border:0;background:transparent;color:var(--muted);
    padding:7px 14px;cursor:pointer;letter-spacing:.04em}
  .switch button[aria-pressed="true"]{background:var(--ink);color:var(--bg)}
  .pdflink{font-family:var(--mono);font-size:12px;text-decoration:none;color:var(--ink);
    border:1px solid var(--line2);border-radius:9px;padding:7px 12px;display:inline-flex;
    align-items:center;gap:6px;background:var(--panel);white-space:nowrap;letter-spacing:.02em}
  .pdflink:hover{background:var(--panel2);border-color:var(--crude);color:var(--crude)}

  /* ---- layout ---- */
  main{flex:1;min-height:0;position:relative}
  .view{position:absolute;inset:0;display:none}
  .view.active{display:flex}

  /* map view — .view.active provides display:flex; don't set it by #id (would beat .active) */
  .rail{width:250px;flex:0 0 250px;overflow-y:auto;border-right:1px solid var(--line);
    background:var(--panel);padding:14px 14px 40px}
  .rail h2{font-family:var(--mono);font-size:11px;letter-spacing:.14em;text-transform:uppercase;
    color:var(--muted);margin:18px 0 8px;font-weight:600}
  .rail h2:first-child{margin-top:2px}
  .seg{display:flex;gap:4px;background:var(--panel2);border:1px solid var(--line);
    border-radius:8px;padding:3px}
  .seg button{flex:1;appearance:none;border:0;background:transparent;color:var(--muted);
    font-family:var(--mono);font-size:12px;padding:6px 4px;border-radius:6px;cursor:pointer}
  .seg button[aria-pressed="true"]{background:var(--panel);color:var(--ink);
    box-shadow:var(--shadow);font-weight:600}
  .tog{display:flex;align-items:center;gap:9px;padding:5px 4px;cursor:pointer;
    border-radius:7px;user-select:none}
  .tog:hover{background:var(--faint)}
  .tog input{position:absolute;opacity:0;pointer-events:none}
  .box{width:15px;height:15px;border-radius:4px;border:1.5px solid var(--line2);
    display:grid;place-items:center;flex:0 0 auto;transition:.12s}
  .tog input:checked + .box{background:var(--ink);border-color:var(--ink)}
  .box svg{width:10px;height:10px;stroke:var(--bg);stroke-width:3;fill:none;
    opacity:0;stroke-linecap:round;stroke-linejoin:round}
  .tog input:checked + .box svg{opacity:1}
  .tog .lab{font-size:13px}
  .tog .swatch{width:12px;height:12px;flex:0 0 auto;margin-left:auto}
  .tog .swatch svg{display:block}
  .muted-note{font-size:11px;color:var(--muted);line-height:1.45;margin-top:6px;font-family:var(--mono)}

  /* map canvas */
  .canvas{position:relative;flex:1;min-width:0;background:var(--ocean);overflow:hidden}
  .maplayer{position:absolute;inset:0;width:100%;height:100%;display:block}
  .canvas{cursor:grab;touch-action:none}
  .canvas.grab{cursor:grabbing}
  #mapCanvas,#mapTop{pointer-events:none}
  #viewportTop{pointer-events:visiblePainted}
  .land{fill:var(--land);stroke:var(--landline);stroke-width:.5;
    vector-effect:non-scaling-stroke}
  .border{fill:none;stroke:var(--landline);stroke-width:1.1;vector-effect:non-scaling-stroke;opacity:.9}
  .hl{filter:drop-shadow(0 0 6px var(--accent))}

  /* controls overlay */
  .zoombar{position:absolute;right:14px;bottom:14px;display:flex;flex-direction:column;
    gap:1px;background:var(--line);border:1px solid var(--line2);border-radius:9px;overflow:hidden;box-shadow:var(--shadow)}
  .zoombar button{width:34px;height:34px;border:0;background:var(--panel);color:var(--ink);
    font-size:17px;cursor:pointer;font-family:var(--mono)}
  .zoombar button:hover{background:var(--panel2)}
  .scalehint{position:absolute;left:14px;bottom:12px;font-family:var(--mono);font-size:11px;
    color:var(--muted);background:var(--panel);padding:4px 8px;border-radius:6px;
    border:1px solid var(--line);opacity:.9}

  /* detail panel */
  .detail{width:300px;flex:0 0 300px;border-left:1px solid var(--line);background:var(--panel);
    padding:18px 18px 40px;overflow-y:auto}
  .detail .placeholder{color:var(--muted);font-size:13.5px;line-height:1.6}
  .detail .kicker{font-family:var(--mono);font-size:10.5px;letter-spacing:.14em;
    text-transform:uppercase;display:inline-flex;align-items:center;gap:6px;padding:3px 8px;
    border-radius:20px;font-weight:600}
  .detail h3{font-size:17px;margin:12px 0 2px;letter-spacing:-.01em;line-height:1.25}
  .detail .role{color:var(--muted);font-size:13.5px;margin:6px 0 14px}
  .kv{display:grid;grid-template-columns:auto 1fr;gap:6px 14px;font-size:13px;
    border-top:1px solid var(--line);padding-top:12px}
  .kv dt{font-family:var(--mono);font-size:11px;letter-spacing:.06em;text-transform:uppercase;
    color:var(--muted);align-self:center}
  .kv dd{margin:0;font-variant-numeric:tabular-nums;text-align:right;font-weight:500}
  .cap-big{font-family:var(--mono);font-size:26px;font-weight:650;letter-spacing:-.02em}
  .cap-unit{font-size:12px;color:var(--muted);font-family:var(--mono)}

  /* legend */
  .legend{display:flex;flex-wrap:wrap;gap:6px 16px;font-family:var(--mono);font-size:11px;
    color:var(--muted);padding:8px 14px;border-top:1px solid var(--line);background:var(--panel)}
  .legend .li{display:flex;align-items:center;gap:6px}
  .legend svg{overflow:visible}

  /* ---- flow view ---- */
  #flowview{overflow-y:auto;padding:26px 20px 60px;justify-content:center}
  .flowwrap{max-width:1000px;width:100%;margin:0 auto}

  /* responsive: collapse rail/detail on small screens */
  @media (max-width:900px){
    .rail{position:absolute;z-index:5;height:100%;box-shadow:var(--shadow);transform:translateX(-100%);transition:.2s}
    .rail.open{transform:none}
    .detail{position:absolute;right:0;z-index:5;height:100%;transform:translateX(100%);transition:.2s}
    .detail.open{transform:none}
    .mobtoggle{display:inline-flex!important}
  }
  .mobtoggle{display:none;align-items:center;gap:6px;font-family:var(--mono);font-size:12px;
    border:1px solid var(--line2);background:var(--panel);color:var(--ink);border-radius:8px;
    padding:6px 10px;cursor:pointer}
  :focus-visible{outline:2px solid var(--accent);outline-offset:2px;border-radius:4px}

  /* ---- theme toggle ---- */
  .themebtn{appearance:none;font-family:var(--mono);font-size:13px;border:1px solid var(--line2);
    background:var(--panel);color:var(--ink);border-radius:9px;padding:6px 10px;cursor:pointer}
  .themebtn:hover{background:var(--panel2)}

  /* ---- module switcher (shown only when >1 module) ---- */
  #modSwitch[hidden]{display:none}

  /* ---- notices ---- */
  #notices{position:absolute;top:12px;left:50%;transform:translateX(-50%);z-index:6;
    display:flex;flex-direction:column;gap:6px;max-width:min(560px,calc(100% - 32px))}
  .notice{font-family:var(--mono);font-size:12px;background:var(--panel);color:var(--ink);
    border:1px solid var(--crude);border-radius:8px;padding:8px 12px;box-shadow:var(--shadow)}
  .notice code{font-size:11px}

  /* ---- flow view (shared across modules) ---- */
  .flowwrap p.lead{color:var(--muted);max-width:60ch;margin:0 auto 30px;text-align:center;font-size:14px}
  .chain{margin:0 0 42px}
  .chain > h3{font-size:15px;font-family:var(--mono);letter-spacing:.06em;text-transform:uppercase;
    display:flex;align-items:center;gap:10px;margin:0 0 16px}
  .chain > h3 .dot{width:11px;height:11px;border-radius:3px}
  .stages{display:flex;flex-wrap:wrap;align-items:stretch;gap:0}
  .stage{flex:1 1 0;min-width:130px;background:var(--panel);border:1px solid var(--line);
    border-radius:11px;padding:13px 13px 14px;box-shadow:var(--shadow);position:relative}
  .stage .n{font-family:var(--mono);font-size:10px;color:var(--muted);letter-spacing:.1em}
  .stage h4{margin:3px 0 6px;font-size:14px;letter-spacing:-.01em}
  .stage p{margin:0;font-size:12px;color:var(--muted);line-height:1.5}
  .arrow{flex:0 0 26px;display:grid;place-items:center;color:var(--muted)}
  .arrow svg{width:18px;height:18px}
  @media (max-width:720px){
    .arrow{flex-basis:100%;height:22px;transform:rotate(90deg)}
    .stage{flex-basis:100%}
  }
  @media (max-width:720px){
    header{gap:8px 10px;padding:10px 14px}
    .h1 i, .h1 > span{display:none}
    .pdflink{padding:5px 9px;font-size:11px}
    .switch button{padding:6px 10px}
  }
  .chain .dot{background:var(--c)} .chain .stage{border-top:3px solid var(--c)}