:root{--ink: #141414;--body: #707070;--muted: #adadad;--border: #ededed;--mist: #f2f2f2;--canvas: #ffffff;--pill: 9999px;--card: 16px;color-scheme:light}*{box-sizing:border-box}body{margin:0;font-family:Inter,Geist,ui-sans-serif,system-ui,sans-serif;background:var(--canvas);color:var(--ink);min-height:100vh;-webkit-font-smoothing:antialiased}button{font-family:inherit}.top{display:flex;align-items:center;justify-content:space-between;gap:16px;padding:12px 24px;border-bottom:1px solid var(--border);min-height:60px}.brand{font-weight:600;font-size:14px;flex:0 0 auto}.crumb{color:var(--body);font-size:14px;font-weight:440;text-align:center;flex:1 1 auto}.pill{-webkit-appearance:none;-moz-appearance:none;appearance:none;border-radius:var(--pill);border:1px solid var(--ink);background:transparent;color:var(--ink);font-size:14px;font-weight:600;padding:8px 16px;cursor:pointer;line-height:1.2}.pill.solid{background:var(--ink);color:#fff;border-color:var(--ink)}.pill.ghost{border-color:var(--muted);color:var(--muted)}.pill:disabled{opacity:.5;cursor:not-allowed}.pill:focus-visible{outline:2px solid var(--ink);outline-offset:3px}.pill:not(:disabled):active{opacity:.82}main{max-width:1280px;margin:0 auto;padding:24px}.meta{display:flex;gap:8px;flex-wrap:wrap;margin-bottom:16px;align-items:center}.tag{border-radius:var(--pill);border:1px solid var(--border);background:var(--mist);color:var(--body);font-size:12px;padding:4px 12px}h1{font-size:32px;line-height:1.15;letter-spacing:-.02em;font-weight:650;margin:0 0 8px}.sub{color:var(--body);font-size:16px;margin:0 0 24px;line-height:1.45}.hint-banner{margin:-8px 0 24px;padding:12px 16px;border:1px solid var(--border);border-radius:var(--card);background:var(--mist);color:var(--ink);font-size:13px;line-height:1.5}.hint-banner[hidden]{display:none}.split{display:grid;grid-template-columns:1fr 1fr;gap:16px;min-height:480px}@media(max-width:900px){.split{grid-template-columns:1fr}.crumb{font-size:13px}}@media(max-width:640px){.top{flex-wrap:wrap;align-items:flex-start}.crumb{order:3;flex:1 1 100%;text-align:left}}.panel{border:1px solid var(--border);border-radius:var(--card);background:var(--canvas);display:flex;flex-direction:column;overflow:hidden;min-height:100%}.panel-head{display:flex;justify-content:space-between;align-items:center;gap:12px;padding:12px 16px;border-bottom:1px solid var(--border);font-size:14px;font-weight:600}.panel-head span{color:var(--body);font-weight:400;text-align:right}.well{flex:1;background:var(--mist);margin:16px;border-radius:12px;min-height:360px;position:relative;overflow:hidden;user-select:none;-webkit-user-select:none;touch-action:none}.well canvas{position:absolute;top:0;right:0;bottom:0;left:0;width:100%;height:100%;display:block;touch-action:none;cursor:crosshair;background:transparent}.hint{position:absolute;top:0;right:0;bottom:0;left:0;display:flex;align-items:center;justify-content:center;color:var(--muted);font-size:14px;pointer-events:none;margin:0;padding:24px;text-align:center}.hint[hidden]{display:none}.solution{padding:16px 20px 24px;font-size:15px;line-height:1.6;color:var(--body)}.solution ol{margin:0;padding-left:1.25rem}.solution li{margin:8px 0}.solution li.miss{color:var(--ink);font-weight:600;text-decoration:underline;text-underline-offset:3px;text-decoration-thickness:1px}.solution .note{margin-top:16px;padding:12px 16px;border:1px solid var(--border);border-radius:var(--card);background:var(--mist);font-size:13px;color:var(--ink);line-height:1.5}.solution .note[hidden]{display:none}.label{display:inline-block;border-radius:var(--pill);border:1px solid var(--ink);padding:2px 10px;font-size:11px;font-weight:600;margin-bottom:8px;color:var(--ink);background:var(--canvas)}.footer{display:flex;justify-content:space-between;align-items:center;gap:12px;margin-top:20px;flex-wrap:wrap}.footer-left{display:flex;gap:8px;flex-wrap:wrap}.sr{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}.brand-link{text-decoration:none;color:var(--ink)}a.pill{text-decoration:none;display:inline-block;white-space:nowrap;line-height:1.2}.track-main{max-width:560px;margin:0 auto;padding:32px 24px 80px}.stage{margin:28px 0 8px;font-size:12px;font-weight:650;letter-spacing:.06em;text-transform:uppercase;color:var(--muted);text-align:center}.path{position:relative;display:flex;flex-direction:column;padding:8px 0}.path:before{content:"";position:absolute;left:50%;top:28px;bottom:28px;width:4px;margin-left:-2px;background:var(--border);border-radius:2px;z-index:0}.node{position:relative;z-index:1;display:grid;grid-template-columns:1fr 72px 1fr;align-items:center;min-height:84px;margin:2px 0}.node.left .node-label{grid-column:1;text-align:right;padding-right:16px}.node.left .dot{grid-column:2;justify-self:center}.node.left .spacer{grid-column:3}.node.right .spacer{grid-column:1}.node.right .dot{grid-column:2;justify-self:center}.node.right .node-label{grid-column:3;text-align:left;padding-left:16px}.node-label strong{display:block;font-size:14px;font-weight:600;letter-spacing:-.01em;color:var(--ink)}.node-label span{display:block;margin-top:4px;font-size:12px;color:var(--body)}.dot{-webkit-appearance:none;-moz-appearance:none;appearance:none;width:56px;height:56px;border-radius:50%;display:flex;align-items:center;justify-content:center;font-size:13px;font-weight:700;background:var(--canvas);border:3px solid var(--border);color:var(--muted);padding:0;cursor:pointer;font-family:inherit}.dot:focus-visible{outline:2px solid var(--ink);outline-offset:3px}.dot:disabled{cursor:not-allowed}.node.done .dot{border-color:var(--ink);color:var(--ink);background:var(--canvas)}.node.done .dot .n{display:none}.node.done .dot:after{content:"✓";font-size:18px}.node.current .dot{background:var(--ink);border-color:var(--ink);color:#fff;box-shadow:0 0 0 6px #14141414}.node.locked .dot{background:var(--mist);border-color:var(--mist);color:var(--muted)}.node.locked .node-label strong,.node.locked .node-label span{color:var(--muted)}.node.exam .dot{border-radius:14px}.legend{margin-top:48px;padding:16px;border:1px solid var(--border);border-radius:var(--card);display:flex;flex-wrap:wrap;gap:16px 24px;font-size:12px;color:var(--body)}.legend i{display:inline-block;width:12px;height:12px;border-radius:50%;margin-right:8px;vertical-align:-1px;border:2px solid var(--ink)}.legend .l-done{background:#fff}.legend .l-now{background:var(--ink)}.legend .l-lock{background:var(--mist);border-color:var(--mist)}.track-summary{margin:24px 0 0;text-align:center;font-size:13px;color:var(--body)}.track-actions{margin-top:16px;display:flex;justify-content:center}.header-actions{display:flex;align-items:center;gap:8px;flex:0 0 auto}