:root{color-scheme:light;--paper:#f4f1e8;--ink:#26302b;--teal:#1f7a63;--teal-edge:#155a48;--line:#d8d2c0;--sage:#4f7a56;--brick:#a6352e;--stain:#8a6a4a}*{box-sizing:border-box}body{margin:0;background:var(--paper);color:var(--ink);font:17px/1.5 system-ui,-apple-system,sans-serif}main{width:min(1160px,100% - 48px);margin:auto;padding:42px 0 30px}header{display:flex;align-items:end;justify-content:space-between;gap:30px;border-bottom:2px solid var(--ink);padding-bottom:24px;margin-bottom:24px}h1{font:600 clamp(40px,6vw,72px)/.95 Georgia,serif;letter-spacing:-3px;margin:0}h1 span{color:var(--teal)}header p{max-width:290px;margin:0}h2,h3{margin:0 0 12px;font-family:Georgia,serif;line-height:1.18}h2{font-size:27px}p{margin:0 0 18px}button,summary,a{touch-action:manipulation}button{font:600 16px/1.2 system-ui;min-height:48px;border:1px solid var(--line);border-radius:10px;background:transparent;color:inherit;padding:12px 18px;cursor:pointer;transition:transform .16s}button:hover{background:#e9e3d2}button:active{transform:scale(.96)}button:focus-visible,summary:focus-visible,a:focus-visible{outline:3px solid var(--teal);outline-offset:4px}button:disabled{opacity:.42;cursor:default;transform:none}.lab{display:grid;grid-template-columns:1fr 1.05fr;gap:48px}.trace{min-width:0}.trace-heading{display:flex;align-items:start;justify-content:space-between;gap:10px}#progress{white-space:nowrap;font:600 14px system-ui;padding-top:6px}#ticket{border-left:4px solid var(--teal);background:#e9e7d6;padding:14px 12px;margin:20px 0;font:14px/1.5 ui-monospace,monospace;overflow-wrap:anywhere;min-height:48px}.save-notice{font:600 12px system-ui;color:#6d6656;margin:-10px 0 16px}.primary{background:var(--teal);border-color:var(--teal-edge);color:white;box-shadow:0 4px 0 var(--teal-edge)}.primary:hover{background:#279476}.quiet{border:0;text-decoration:underline}.quiet.back{padding-inline:8px}.explanation{min-width:0;padding-left:30px;border-left:1px solid var(--line)}.choices{display:flex;gap:10px;flex-wrap:wrap;margin:12px 0 18px}.choices button[aria-pressed=true]{background:var(--ink);border-color:var(--ink);color:white}#verdict{min-height:0;color:var(--sage);font-weight:600}#verdict[data-correct=false]{color:var(--brick)}#verdict:empty{display:none}#diagram{margin:24px 0;padding:20px 0;border-block:1px solid var(--line)}#diagram svg{width:100%;height:auto;display:block}.zone-lock{font:600 13px system-ui;color:#6d6656;margin:-8px 0 14px}.qr-cell{fill:var(--ink)}.qr-cell.lite{fill:#fffdf6}.qr-bg{fill:#fffdf6;stroke:var(--ink);stroke-width:2}.qr-hi{fill:none;stroke:var(--teal);stroke-width:2.6}.qr-dim{opacity:.28}.qr-smudged{fill:var(--stain);opacity:.75}.qr-hit{fill:transparent;cursor:pointer}.qr-hit:focus-visible{outline:none;stroke:var(--teal);stroke-width:2}.stain-ring{fill:none;stroke:var(--stain);stroke-width:2;stroke-dasharray:3 5;opacity:.8}.barcode-line{stroke:var(--ink);stroke-width:2.4}.caption{font:600 12px system-ui;fill:#6d6656}.faint-text{font:600 11px system-ui;fill:#a39a83}.station-label{font:600 12px system-ui;fill:var(--ink)}.question{font:700 13px ui-monospace,monospace;fill:var(--teal)}.slip-body{fill:#e9e7d6;stroke:var(--line)}.slip-text{font:600 9.5px ui-monospace,monospace;fill:var(--ink)}.cross{stroke:var(--brick);stroke-width:3;stroke-linecap:round}.zig{fill:none;stroke:var(--teal);stroke-width:2.4;stroke-linecap:round;stroke-linejoin:round}.bit{font:700 12px ui-monospace,monospace;fill:var(--ink)}.bit.lite{fill:#fffdf6}.halo{fill:none;stroke:var(--teal);stroke-width:2.4;stroke-dasharray:4 3}.arrow-cue{fill:none;stroke:var(--teal);stroke-width:2.6;stroke-linecap:round;stroke-linejoin:round}.locked-label{font:600 11px system-ui;fill:#6d6656}.logo-disc{fill:#fffdf6;stroke:var(--brick);stroke-width:2.4;stroke-dasharray:5 4}#prediction.locked{opacity:.45;pointer-events:none}#predictionQuestion{font-weight:600}button[data-answer]{min-width:125px}[hidden]{display:none!important}@media(max-width:750px){main{width:calc(100% - 32px);padding-top:28px}header{display:block;margin-bottom:18px;padding-bottom:20px;position:relative}h1{letter-spacing:-2px}header p{margin-top:14px;max-width:100%;font-size:16px}.lab{grid-template-columns:1fr;gap:28px}.explanation{padding:0;border:0}.trace-heading h2{font-size:25px}#ticket{margin:12px 0 18px}.primary{flex:1}#diagram{margin:20px 0}}@media(orientation:landscape) and (max-height:500px){main{padding-top:18px}.lab{grid-template-columns:1fr 1fr;gap:25px}header{display:flex}header p{max-width:290px}h1{font-size:44px}.explanation{padding-left:20px;border-left:1px solid var(--line)}}@media(prefers-reduced-motion:reduce){*{transition:none!important;animation:none!important;scroll-behavior:auto!important}}

/* Quiet info icon: explanations, sources and limits stay on demand. */
.info-btn{min-width:40px;width:40px;min-height:40px;height:40px;border-radius:50%;padding:0;font:italic 600 18px Georgia,serif;color:#6d6656;flex:none}
.info-btn:hover{background:#e9e3d2}
#infoDialog h3{margin:18px 0 8px;font-size:19px}
#infoDialog p{font-size:15px}
#infoDialog nav{display:grid;gap:10px;padding:4px 0 14px}
@media(max-width:750px){.info-btn{position:absolute;top:0;right:0}}

/* Navigation follows the reading flow without covering it. */
:root{--dock-space:100px}html{scroll-padding-bottom:calc(var(--dock-space) + 20px)}body{padding-bottom:calc(var(--dock-space) + env(safe-area-inset-bottom,0px))}main{padding-bottom:32px}.action-dock{position:fixed;z-index:10;inset:auto 0 0;background:var(--paper);border-top:1px solid var(--line);padding:14px 24px calc(18px + env(safe-area-inset-bottom,0px));box-shadow:0 -6px 24px #26302b08}.dock-inner{max-width:1160px;margin:auto;display:flex;align-items:center;gap:20px}.action-hint{margin-left:auto;color:#6d6656;font:13px/1.3 system-ui}.action-dock .primary{min-width:160px;background:var(--ink);border-color:var(--ink);box-shadow:0 3px 0 #141a16;color:#fffdf6}.action-dock .primary:hover:not(:disabled){background:#3d4a42}.action-dock .primary:disabled{opacity:1;background:#e6e1d1;border-color:#d6cfba;box-shadow:none;color:#68604e}.action-dock .quiet{font-size:14px}#stepTitle{scroll-margin-top:20px}#stepTitle:focus,#verdict:focus{outline:none}dialog{background:var(--paper);color:var(--ink);border:1px solid var(--line);border-radius:14px;max-width:min(480px,calc(100% - 32px));max-height:84vh;overflow:auto;padding:26px;box-shadow:0 16px 60px #26302b35}dialog::backdrop{background:#26302b65}.dialog-actions{display:flex;gap:12px;flex-wrap:wrap}.dialog-actions #cancelReset,.dialog-actions #closeInfo{background:var(--ink);color:var(--paper)}dialog p{font-size:16px}#verdict{scroll-margin-bottom:120px}
@media(max-width:600px){:root{--dock-space:104px}.action-dock{padding:10px 16px calc(14px + env(safe-area-inset-bottom,0px))}.dock-inner{gap:8px;display:grid;grid-template-columns:auto auto 1fr}.action-hint{grid-row:1;grid-column:1/-1;margin:0;text-align:right;font-size:12px}.action-dock #reset{grid-row:2;padding-left:0}.action-dock #back{grid-row:2}.action-dock .primary{grid-row:2;min-width:0;width:100%;min-height:48px}.explanation{padding-bottom:8px}}
@media(orientation:landscape) and (max-height:500px){:root{--dock-space:84px}.action-dock{padding-top:8px;padding-bottom:calc(12px + env(safe-area-inset-bottom,0px))}}
@media(max-width:600px){.action-dock .primary{font-size:14px;padding-inline:12px;white-space:nowrap}}