:root{--bb-blue: #324dc7;--bb-blue-hover: #28369a;--bb-navy: #1b2264;--bb-header-bg: #e6edf8;--bb-page-bg-tint: #f5f7fc;--bb-focus: #7ab6fd;--bb-yellow: #fedb00;--bb-yellow-hover: #e5c500;--bb-yellow-cell: #fdf4ba;--bb-text: #1e1e1e;--bb-text-muted: #505050;--bb-border: #d9d9d9;--bb-border-strong: #b2b2b2;--bb-page-bg: #f0f0f0;--bb-disabled-text: #888;--bb-card-bg: #ffffff;--bb-pause-bg: #1a1a1a;--bb-flag: #ab2334;--font-ui: "Roboto", "Helvetica Neue", Arial, sans-serif;--font-question: "Crimson Text", "Noto Serif", Georgia, serif;--font-mono: "Courier Prime", ui-monospace, "Courier New", monospace;--font-cjk: "Noto Serif JP", "Noto Serif SC", "Noto Serif", serif;--radius-card: 8px;--radius-pill: 999px;--shadow-card: 0 1px 3px rgba(0, 0, 0, .08)}*{box-sizing:border-box}html,body,#root{height:100%}body{margin:0;background:var(--bb-page-bg);color:var(--bb-text);font-family:var(--font-ui);-webkit-font-smoothing:antialiased}button{font-family:inherit}.app-shell{min-height:100%;display:flex;flex-direction:column}.band{background:var(--bb-header-bg);padding:0 40px 34px}.band-top{display:flex;align-items:center;justify-content:space-between;height:68px}.wordmark{display:flex;align-items:center;gap:8px;font-size:20px;font-weight:700;color:var(--bb-blue);letter-spacing:-.2px}.wordmark svg{flex:none}.band-title{margin:8px 0 0;font-size:2.5rem;font-weight:300;line-height:1.2em;letter-spacing:-1.5px;color:var(--bb-blue)}.content{flex:1;padding:34px 40px 80px;max-width:1180px;width:100%}.pack-loading{flex:1;display:grid;place-items:center;padding:80px 40px;font-size:15px;color:var(--bb-text-muted)}.section-head{display:flex;align-items:center;gap:18px;margin-bottom:22px}.section-head h2{margin:0;font-size:30px;font-weight:700;letter-spacing:-.3px}.section-head .spacer{flex:1}.textlink{background:none;border:0;padding:0;color:var(--bb-blue);font-size:15px;font-weight:500;text-decoration:underline;cursor:pointer}.textlink:hover{color:var(--bb-blue-hover)}.segmented{display:inline-flex;border:1px solid var(--bb-border-strong);border-radius:6px;overflow:hidden;background:#fff}.segmented button{border:0;background:#fff;padding:7px 20px;font-size:15px;font-weight:500;color:var(--bb-text);cursor:pointer;display:inline-flex;align-items:center;gap:6px}.segmented button+button{border-left:1px solid var(--bb-border-strong)}.segmented button[aria-pressed=true]{background:#29292b;color:#fff}.segmented button:focus-visible{outline:2px solid var(--bb-focus);outline-offset:-2px}.subsection-head{margin-top:8px}.subsection-head h3{margin:0;font-size:22px;font-weight:700;letter-spacing:-.2px}.year-filter{display:inline-flex;align-items:center;gap:2px;border:1px solid var(--bb-border-strong);border-radius:var(--radius-pill);padding:4px;background:#fff}.year-filter button{border:0;background:transparent;padding:8px 18px;font-size:14px;font-weight:700;color:var(--bb-disabled-text);border-radius:var(--radius-pill);cursor:pointer}.year-filter button:hover{color:var(--bb-text)}.year-filter button.is-on{background:var(--bb-blue);color:#fff}.year-filter button:focus-visible{outline:2px solid var(--bb-focus);outline-offset:2px}.card-grid{display:flex;flex-wrap:wrap;gap:24px}.tile{width:216px;min-height:190px;background:var(--bb-card-bg);border:1px solid var(--bb-border);border-radius:var(--radius-card);box-shadow:var(--shadow-card);padding:22px 18px;display:flex;flex-direction:column;align-items:center;justify-content:center;gap:14px;text-align:center;cursor:pointer}.tile:focus-visible{outline:3px solid var(--bb-focus);outline-offset:2px}.tile-title{font-size:17px;font-weight:700;line-height:1.3}.tile-sub{font-size:13px;color:var(--bb-text-muted)}.tile-icon{width:56px;height:56px;display:grid;place-items:center;color:var(--bb-blue)}.empty-card{max-width:452px;background:var(--bb-card-bg);border:1px solid var(--bb-border);border-radius:var(--radius-card);box-shadow:var(--shadow-card);padding:28px 30px;text-align:center}.empty-card h3{margin:0 0 12px;font-size:17px}.empty-card p{margin:0;font-size:15px;line-height:1.5;color:var(--bb-text-muted)}.row-list{display:flex;flex-direction:column;gap:12px;max-width:640px}.row{display:flex;align-items:center;gap:16px;width:100%;text-align:left;background:var(--bb-card-bg);border:1px solid var(--bb-border);border-radius:var(--radius-card);box-shadow:var(--shadow-card);padding:18px 20px;cursor:pointer;font-size:16px}.row:focus-visible{outline:3px solid var(--bb-focus);outline-offset:2px}.row .row-main{flex:1}.row .row-title{font-weight:700;font-size:17px}.row .row-sub{font-size:13px;color:var(--bb-text-muted);margin-top:3px}.row .chev{color:var(--bb-border-strong)}.row-inprogress .row-sub{color:var(--bb-blue);font-weight:500}.row-actions{display:flex;align-items:center;gap:16px;flex:none}.crumb{display:flex;align-items:center;gap:8px;margin-bottom:18px;font-size:14px;color:var(--bb-text-muted)}.crumb button{background:none;border:0;padding:0;color:var(--bb-blue);font-size:14px;cursor:pointer;text-decoration:underline}.panel{max-width:520px;background:var(--bb-card-bg);border:1px solid var(--bb-border);border-radius:var(--radius-card);box-shadow:var(--shadow-card);padding:26px 28px 30px}.panel h3{margin:0 0 14px;font-size:18px}.panel h4{margin:24px 0 10px;font-size:15px}.switch-row{display:flex;align-items:center;gap:14px}.switch-row label{font-size:15px;color:var(--bb-blue)}.switch{position:relative;width:52px;height:28px;border-radius:var(--radius-pill);border:0;background:#b9bfc9;cursor:pointer;transition:background .14s ease;flex:none}.switch[aria-checked=true]{background:var(--bb-blue)}.switch:after{content:"";position:absolute;top:3px;left:3px;width:22px;height:22px;border-radius:50%;background:#fff;transition:transform .14s ease}.switch[aria-checked=true]:after{transform:translate(24px)}.note{margin:18px 0 0;font-size:13px;line-height:1.55;color:var(--bb-text-muted)}.field{margin-top:18px}.field>span{display:block;font-size:15px;font-weight:700;margin-bottom:8px}select.select{width:100%;padding:12px 14px;font-size:15px;font-family:inherit;color:var(--bb-text);background:#fff;border:1px solid var(--bb-border-strong);border-radius:6px}.check-row{display:flex;align-items:center;gap:12px;padding:7px 0;font-size:15px}.check-row input{width:20px;height:20px;accent-color:var(--bb-blue);margin:0}.disabled-block{opacity:.45;pointer-events:none}.btn{border:0;border-radius:var(--radius-pill);padding:12px 30px;font-size:15px;font-weight:700;cursor:pointer}.btn-primary{background:var(--bb-blue);color:#fff}.btn-primary:hover{background:var(--bb-blue-hover)}.btn-primary:disabled{background:#a8b0c4;cursor:not-allowed}.btn-ghost{background:transparent;color:var(--bb-blue);text-decoration:underline;padding-left:8px}.btn:focus-visible{outline:3px solid var(--bb-navy);outline-offset:2px}.action-bar{display:flex;align-items:center;gap:14px;margin-top:28px;max-width:520px}.action-bar .spacer{flex:1}.placeholder{max-width:620px;border:1px dashed var(--bb-border-strong);border-radius:var(--radius-card);background:#fff;padding:30px}.placeholder h3{margin:0 0 12px;font-size:20px}.placeholder pre{background:#f3f4f6;border-radius:6px;padding:14px;font-size:13px;overflow-x:auto}@media (prefers-reduced-motion: reduce){*{transition:none!important;animation:none!important}}@media (max-width: 720px){.band{padding:0 20px 26px}.band-title{font-size:28px}.content{padding:24px 20px 60px}.section-head{flex-wrap:wrap;gap:12px}.section-head h2{font-size:24px}.tile{width:100%}}:root{--pin-mask: url(data:image/svg+xml,%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20viewBox%3D%220%200%2024%2024%22%3E%3Cpath%20d%3D%22M12%2012.56Q11.04%2012.56%2010.2%2012.19Q9.35%2011.81%208.72%2011.19Q8.09%2010.57%207.71%209.7Q7.36%208.86%207.36%207.9Q7.36%206.94%207.71%206.09Q8.09%205.25%208.72%204.62Q9.35%203.98%2010.2%203.61Q11.04%203.26%2012%203.26Q12.96%203.26%2013.8%203.61Q14.65%203.98%2015.28%204.62Q15.91%205.25%2016.29%206.09Q16.64%206.94%2016.64%207.9Q16.64%208.86%2016.29%209.7Q15.91%2010.57%2015.28%2011.19Q14.65%2011.81%2013.8%2012.19Q12.96%2012.56%2012%2012.56ZM12%204.99Q10.8%204.99%209.95%205.85Q9.09%206.7%209.09%207.9Q9.09%209.12%209.95%209.96Q10.8%2010.8%2012%2010.8Q13.2%2010.8%2014.05%209.96Q14.91%209.12%2014.91%207.9Q14.91%206.7%2014.05%205.85Q13.2%204.99%2012%204.99ZM12%2024Q11.81%2024%2011.61%2023.94Q11.41%2023.88%2011.23%2023.77Q11.11%2023.7%2011%2023.59Q10.9%2023.48%2010.8%2023.34Q10.01%2022.1%208.79%2020.09Q7.59%2018.09%206.47%2015.91Q5.34%2013.73%204.52%2011.67Q3.73%209.61%203.73%208.27Q3.73%206.56%204.38%205.06Q5.02%203.56%206.14%202.44Q7.27%201.31%208.79%200.66Q10.29%200%2012%200Q13.71%200%2015.21%200.66Q16.73%201.31%2017.86%202.44Q18.98%203.56%2019.62%205.06Q20.27%206.56%2020.27%208.27Q20.27%209.63%2019.48%2011.7Q18.66%2013.73%2017.53%2015.91Q16.41%2018.09%2015.19%2020.11Q13.99%2022.1%2013.2%2023.34Q12.98%2023.67%2012.66%2023.84Q12.33%2024%2011.98%2024ZM12%201.76Q10.64%201.76%209.47%202.27Q8.27%202.79%207.38%203.67Q6.49%204.55%206%205.74Q5.48%206.94%205.48%208.27Q5.48%209.21%206.05%2010.76Q6.61%2012.3%207.54%2014.16Q8.46%2016.01%209.63%2018.05Q10.8%2020.06%2012%2021.96Q13.2%2020.06%2014.37%2018.02Q15.54%2016.01%2016.46%2014.16Q17.39%2012.3%2017.95%2010.76Q18.52%209.21%2018.52%208.27Q18.52%206.94%2018.02%205.74Q17.51%204.55%2016.62%203.67Q15.73%202.79%2014.53%202.27Q13.36%201.76%2012%201.76Z%22%2F%3E%3C%2Fsvg%3E)}.player{position:fixed;top:0;right:0;bottom:0;left:0;display:flex;flex-direction:column;background:#fff}.player-head{z-index:50;display:grid;grid-template-columns:1fr auto 1fr;align-items:start;gap:16px;padding:14px 22px;min-height:78px;box-sizing:border-box;background:var(--bb-header-bg);position:relative;border-bottom:0}.player-head:after,.player-foot:before{content:"";position:absolute;left:0;right:0;height:2px;background-image:linear-gradient(to right,var(--bb-text) 0 21px,transparent 21px 23px);background-size:23px 2px;background-repeat:round}.player-head:after{bottom:0}.player-foot:before{top:0}.head-title{font-size:22px;font-weight:500;letter-spacing:-.2px}.head-directions{margin-top:1px;background:none;border:0;padding:0;font-size:15px;font-weight:500;color:var(--bb-text);cursor:pointer;display:inline-flex;align-items:center;gap:5px}.head-mid{text-align:center}.head-clock{font-size:22px;font-weight:500;line-height:1.15}.head-clock.is-low{color:var(--bb-flag)}.time-warning{position:fixed;top:84px;left:64px;z-index:60;display:flex;align-items:flex-start;gap:18px;max-width:290px;padding:14px 16px;background:#1e1e1e;color:#fff;border-radius:8px;box-shadow:0 4px 16px #0000004d;font-size:15px;line-height:1.35;margin-top:0}.time-warning button{background:none;border:0;color:#fff;cursor:pointer;padding:0;line-height:1;flex:none}.head-clock-hidden{height:28px}.head-clock-btns{display:flex;gap:7px;justify-content:center;margin-top:3px}.head-clock-btns button{border:1px solid var(--bb-text);background:transparent;border-radius:var(--radius-pill);padding:2px 7px;min-width:50px;box-sizing:border-box;font-size:12px;font-weight:700;cursor:pointer}.head-right{display:flex;gap:24px;justify-content:flex-end;align-items:center;align-self:center}.head-tool{background:none;border:0;cursor:pointer;display:flex;flex-direction:column;align-items:center;justify-content:flex-start;gap:3px;font-size:11px;font-weight:500;color:var(--bb-text)}.head-tool-glyph{height:16px;display:flex;align-items:center;justify-content:center}.head-tool-x2{font-family:var(--font-question);font-style:italic;font-weight:700;font-size:15px;line-height:1}.head-tool-x2 sup{font-size:9px;font-style:normal}.head-tool-glyph{height:17px}.head-tool-glyph svg{width:17px;height:17px}.scrim{position:fixed;top:0;right:0;bottom:0;left:0;background:#0000004d;z-index:35}.directions{position:absolute;top:100%;left:16px;width:min(860px,calc(100vw - 60px));background:#fff;border-radius:4px;box-shadow:0 6px 24px #0000003d;z-index:40;padding:26px 30px 18px}.directions-caret{position:absolute;top:-9px;left:42px;width:18px;height:18px;background:#fff;transform:rotate(45deg)}.directions-body{font-family:var(--font-question);font-size:17px;line-height:1.5;max-height:min(58vh,520px);overflow-y:auto;padding-right:8px}.directions-body p{margin:0 0 14px}.directions-body ul{margin:0 0 14px;padding-left:26px}.directions-body li{margin-bottom:5px}.directions-body .sprdir-examples{text-align:center;margin:18px 0 8px}.directions-body .sprdir-table{margin:0 auto 8px}.directions-foot{display:flex;justify-content:flex-end;margin-top:18px;padding-top:14px}.btn-yellow{background:var(--bb-yellow);color:var(--bb-text);border:1px solid var(--bb-text);border-radius:var(--radius-pill);padding:10px 30px;font-size:15px;font-weight:700;cursor:pointer}.btn-yellow:hover{background:var(--bb-yellow-hover)}.directions-body,.refsheet-body,.pane-scroll{scrollbar-width:thin;scrollbar-color:#888 #f0f0f0}.directions-body::-webkit-scrollbar,.refsheet-body::-webkit-scrollbar,.pane-scroll::-webkit-scrollbar{width:14px}.directions-body::-webkit-scrollbar-track,.refsheet-body::-webkit-scrollbar-track,.pane-scroll::-webkit-scrollbar-track{background:#f0f0f0;box-shadow:inset 0 0 6px #0003}.directions-body::-webkit-scrollbar-thumb,.refsheet-body::-webkit-scrollbar-thumb,.pane-scroll::-webkit-scrollbar-thumb{background:#8886;border-radius:8px;border:2px solid transparent;background-clip:padding-box;min-height:30px}.directions-body::-webkit-scrollbar-thumb:hover,.refsheet-body::-webkit-scrollbar-thumb:hover,.pane-scroll::-webkit-scrollbar-thumb:hover{background:#888888b3;background-clip:padding-box}.practice-banner{background:var(--bb-navy);color:#fff;text-align:center;font-size:12px;font-weight:700;letter-spacing:.4px;height:32px;display:flex;align-items:center;justify-content:center;border-radius:0 0 10px 10px;margin:0 22px}.player-body{flex:1;position:relative;overflow:hidden}.single-pane,.pane-scroll{height:100%;overflow:auto;padding:22px 26px 40px}.single-pane>.question{max-width:720px;margin:0 auto}.question{min-width:330px}.split{display:flex;height:100%}.split-pane{overflow:hidden}.split-divider{position:relative;flex:none;width:2px;background:var(--bb-border-strong);cursor:col-resize}.split-divider.is-dragging{background:var(--bb-blue)}.split-grip{position:absolute;top:50%;left:50%;transform:translate(-50%,-50%);width:14px;height:28px;background:var(--bb-text);border:0;border-radius:4px;display:grid;place-items:center;color:#fff}.split-divider:focus-visible{outline:3px solid var(--bb-focus)}.question{font-family:var(--font-question);font-size:17px;line-height:1.5}.q-head{display:flex;align-items:center;gap:0;height:30px;padding-right:10px;background:var(--bb-page-bg)}.q-num{flex:none;background:var(--bb-text);color:#fff;font-family:var(--font-ui);font-weight:700;font-size:20px;width:26px;height:30px;display:grid;place-items:center}.q-head-spacer{flex:1}.q-flag{margin-left:18px;background:none;border:0;padding:0;cursor:pointer;font-family:var(--font-ui);font-size:14px;display:inline-flex;align-items:center;gap:6px;color:var(--bb-text)}.q-flag-icon{color:var(--bb-text)}.q-flag.is-flagged .q-flag-text{font-weight:700;text-decoration:underline}.q-head-rule{height:2px;margin-top:1px;margin-bottom:16px;background:repeating-linear-gradient(to right,#000 0 17px,transparent 17px 19px)}.q-abc{flex:none;display:grid;place-items:center;width:26px;height:26px;box-sizing:border-box;border:1.5px solid var(--bb-text);border-radius:6px;background:#fff;color:var(--bb-text);padding:0;cursor:pointer}.q-abc.is-on{background:var(--bb-blue);color:#fff}.q-abc:focus-visible{outline:3px solid var(--bb-focus);outline-offset:2px}.q-stimulus{margin:18px 0;text-align:center;font-size:18px}.q-prompt{margin:0 0 20px}.choices{display:flex;flex-direction:column;gap:12px}.choice-row{display:flex;align-items:center;gap:14px}.choice{position:relative;flex:1;display:flex;align-items:center;gap:14px;text-align:left;background:#fff;border:1px solid #767676;border-radius:var(--radius-card);padding:12px 16px;font-family:var(--font-question);font-size:17px;cursor:pointer}.choice:hover{border-color:var(--bb-text)}.choice:focus-visible{outline:3px solid var(--bb-focus);outline-offset:2px}.choice-letter{flex:none;width:24px;height:24px;border:2px solid var(--bb-text-muted);border-radius:50%;display:grid;place-items:center;font-family:var(--font-ui);font-weight:700;font-size:14px;line-height:1;color:var(--bb-text-muted)}.choice-letter{padding-top:.1429em}.choice.is-selected{border-color:var(--bb-blue);box-shadow:inset 0 0 0 1px var(--bb-blue)}.choice.is-selected .choice-letter{background:var(--bb-blue);border-color:var(--bb-text-muted);color:#fff}.choice-content{flex:1}.choice.is-struck{color:var(--bb-border-strong)}.choice.is-struck .choice-letter{color:var(--bb-border-strong);border-color:var(--bb-border-strong)}.choice.is-struck .choice-content{color:var(--bb-border-strong)}.choice.is-struck .choice-strike{position:absolute;left:-4px;right:-5px;top:50%;height:2px;margin-top:-1px;background:#000}.crossout{flex:none;position:relative;box-sizing:border-box;width:18px;height:18px;padding:0;border:1.5px solid var(--bb-text);border-radius:50%;background:#fff;color:var(--bb-text);font-family:var(--font-ui);font-size:11px;cursor:pointer;display:grid;place-items:center}.crossout-letter{line-height:1}.crossout-line{position:absolute;left:-3.5px;right:-3.5px;top:50%;margin-top:-.75px;height:1.5px;background:currentColor}.crossout.is-struck{width:auto;height:auto;border:0;border-radius:0;background:none}.crossout-undo{font-size:15px;font-weight:700;text-decoration:underline;text-underline-offset:2px;text-decoration-thickness:1px}.spr{max-width:420px}.spr-input{width:190px;padding:10px 12px;font-family:var(--font-question);font-size:18px;border:1.6px solid var(--bb-text);border-radius:4px}.spr-input:focus-visible{outline:3px solid var(--bb-focus)}.spr-preview-label{margin-top:26px;font-weight:700;font-size:18px}.spr-preview{min-height:34px;font-size:20px;margin-top:6px}.figure{border:1px solid var(--bb-border);margin:0 auto 18px;min-width:260px}.figure-bar{display:flex;align-items:center;justify-content:flex-end;gap:8px;padding:4px 8px;background:#f7f7f7;border-bottom:1px solid var(--bb-border);font-family:var(--font-ui);font-size:13px}.figure-btn,.figure-reset{background:none;border:0;cursor:pointer;color:var(--bb-text);font-size:13px;padding:2px 4px}.figure-sep{width:1px;height:16px;background:var(--bb-border)}.figure-body{padding:10px;overflow:auto;display:flex;justify-content:safe center;align-items:safe center;max-height:60vh}.figure-body img{max-width:none;flex:none}.figure-full{position:fixed;top:0;right:0;bottom:0;left:0;background:#000000b8;display:grid;place-items:center;z-index:90}.figure-full img{max-width:88vw;max-height:88vh;background:#fff;padding:16px}.figure-full-close{position:absolute;top:18px;right:22px;background:#fff;border:0;border-radius:50%;width:38px;height:38px;cursor:pointer}.qtable-wrap{margin:0 0 18px}.qtable-caption{text-align:center;font-weight:700;margin-bottom:8px}.qtable{border-collapse:collapse;margin:0 auto;font-family:var(--font-question)}.qtable th,.qtable td{border:1px solid var(--bb-text);padding:7px 16px;text-align:center}.qtable th{font-weight:700}.sprdir{font-family:var(--font-question);font-size:16px;line-height:1.5;min-width:300px}.sprdir h2{font-family:var(--font-ui);font-size:20px;margin:0 0 14px}.sprdir ul{padding-left:22px;margin:0 0 20px}.sprdir li,.sprdir-examples{margin-bottom:8px}.sprdir-table{border-collapse:collapse;width:100%;min-width:330px;max-width:460px}.sprdir-table th,.sprdir-table td{border:1px solid var(--bb-text);padding:8px 12px;text-align:center;vertical-align:middle}.sprdir-table code{display:block;white-space:nowrap;background:#ececec;border-radius:4px;font-family:var(--font-mono);font-size:13px;padding:2px 8px;margin:4px auto;width:fit-content}.player-foot{display:grid;grid-template-columns:1fr auto 1fr;align-items:center;padding:12px 22px;background:var(--bb-header-bg);border-top:0;position:relative}.foot-mid{position:relative;display:flex;justify-content:center}.foot-counter{background:var(--bb-text);color:#fff;border:0;border-radius:6px;padding:8px 12px 8px 18px;font-size:15px;font-weight:700;cursor:pointer;display:inline-flex;align-items:center;gap:6px}.foot-right{display:flex;gap:12px;justify-content:flex-end}.player-foot .btn{padding:11px 21px;font-size:14px}.navpop{position:absolute;bottom:calc(100% + 36px);left:50%;transform:translate(-50%);width:min(490px,calc(100vw - 40px));background:#fff;border-radius:var(--radius-card);box-shadow:0 2px 10px #00000029;padding:24px 18px;z-index:50}.navpop:after{content:"";position:absolute;top:100%;left:50%;width:0;height:0;margin-left:-22px;border-left:22px solid transparent;border-right:22px solid transparent;border-top:24px solid #fff;filter:drop-shadow(0 5px 5px rgba(0,0,0,.13))}.navpop-title{text-align:center;font-weight:700;font-size:18px;position:relative;padding-bottom:20px;border-bottom:1px solid var(--bb-border)}.navpop-close{position:absolute;right:0;top:-2px;background:none;border:0;cursor:pointer}.navpop-legend{display:flex;gap:22px;justify-content:center;padding:14px 0;font-size:14px;border-bottom:1px solid var(--bb-border)}.navpop-legend span{display:inline-flex;align-items:center;gap:6px}.legend-unanswered{width:13px;height:13px;border:1px dashed var(--bb-text)}.legend-flag{color:var(--bb-flag)}.navpop-grid,.checkwork-grid{display:grid;grid-template-columns:repeat(10,1fr);justify-items:center;gap:26px 0;padding:24px 0 16px}.navpop-grid{gap:23px 0;padding:29px 0 25px}.checkwork-grid{gap:32px 0}.navcell{position:relative;box-sizing:border-box;width:30px;height:30px;padding:0;display:grid;place-items:center;border:1px dashed var(--bb-text);background:#fff;font-family:var(--font-ui);color:var(--bb-blue);font-weight:700;font-size:20px;line-height:1;cursor:pointer}.navcell-lg{width:40px;height:40px;font-size:24px}.navcell:hover{background:var(--bb-page-bg)}.navcell.is-answered{background:var(--bb-blue);color:#fff;border:1px solid var(--bb-blue)}.navcell.is-answered:hover{background:var(--bb-blue-hover);border-color:var(--bb-blue-hover)}.navcell.is-current:after{content:"";position:absolute;left:50%;top:-17px;transform:translate(-50%);width:14px;height:18px;background:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 14 18'%3E%3Cpath d='M7 1.1c-3.1 0-5.6 2.5-5.6 5.6 0 3.9 4.6 9.2 5.1 9.8a.65.65 0 0 0 1 0c.5-.6 5.1-5.9 5.1-9.8 0-3.1-2.5-5.6-5.6-5.6z' fill='%23fff' stroke='%231e1e1e' stroke-width='1.7'/%3E%3Ccircle cx='7' cy='6.7' r='1.9' fill='%231e1e1e'/%3E%3C/svg%3E") center / contain no-repeat}.navcell-flag{position:absolute;top:-7px;right:-6px;color:var(--bb-flag);display:block}.navcell-lg .navcell-flag{top:-8px;right:-7px}.legend-flag{color:var(--bb-flag);display:inline-block}.navpop-foot{display:flex;justify-content:center}.btn-outline{border:1px solid var(--bb-blue);background:#fff;color:var(--bb-blue);border-radius:var(--radius-pill);padding:8px 22px;font-weight:700;font-size:14px;cursor:pointer}.checkwork{max-width:780px;margin:30px auto;text-align:center}.checkwork h1{font-weight:400;font-size:34px;letter-spacing:-1px;margin:0 0 22px}.checkwork p{margin:10px 0;font-size:15px;line-height:1.5}.checkwork-page{background:#fafafa}.checkwork-card{margin-top:26px;background:#fff;border:0;border-radius:8px;box-shadow:0 2px 10px #00000029;padding:22px 28px 12px;text-align:left}.checkwork-head{display:flex;justify-content:space-between;align-items:center;font-weight:700;padding-bottom:12px;border-bottom:1px solid var(--bb-border)}.checkwork-legend{display:flex;gap:18px;font-weight:400;font-size:13px}.checkwork-legend span{display:inline-flex;align-items:center;gap:6px}.pause,.break{position:fixed;top:0;right:0;bottom:0;left:0;background:var(--bb-pause-bg);color:#fff;display:grid;grid-template-columns:1fr 1fr;align-items:center;gap:40px;padding:0 8vw}.pause-left{display:flex;flex-direction:column;align-items:flex-start;gap:14px}.break-left{display:flex;flex-direction:column;align-items:center;gap:26px}.pause-module{display:flex;align-items:center;gap:10px;font-weight:700;font-size:14px}.pause-clockbox{border:1px solid #fff;border-radius:6px;padding:14px 34px;text-align:center;min-width:270px}.pause-clock-label{font-size:15px;font-weight:700}.pause-clock{font-size:56px;font-weight:700;line-height:1.1}.pause-right h2,.break-right h2{font-size:30px;margin:0 0 14px}.pause-right p,.break-right p{font-size:17px;line-height:1.5;margin:0 0 22px;max-width:420px}.break-right{max-height:84vh;overflow-y:auto}.break-right hr{border:0;border-top:1px solid #666;margin:26px 0}.break-right ol{padding-left:20px}.break-right li{margin-bottom:10px;font-size:16px}.transition{position:fixed;top:0;right:0;bottom:0;left:0;display:flex;flex-direction:column;align-items:center;justify-content:center;gap:6px;background:#fafafa}.transition h1{color:var(--bb-blue);font-weight:300;font-size:2.2rem;letter-spacing:-1px;margin-bottom:12px}.transition p{margin:2px 0;font-size:16px}.spinner{position:relative;width:60px;height:60px;margin-top:34px}.spinner span{position:absolute;left:50%;top:50%;width:6px;height:6px;margin:-3px;border-radius:50%;background:var(--bb-text);animation:spin 1.1s linear infinite}@keyframes spin{0%{opacity:1}to{opacity:.1}}.refsheet{position:absolute;top:0;right:0;bottom:0;width:380px;background:#fff;border-left:3px solid var(--bb-text);display:flex;flex-direction:column;z-index:30}.refsheet-bar{display:flex;justify-content:space-between;align-items:center;background:#1a1a1a;color:#fff;padding:10px 14px;font-weight:700}.refsheet-bar-actions{display:flex;gap:12px}.refsheet-bar button{background:none;border:0;color:#fff;cursor:pointer}.refsheet-body{flex:1;overflow-y:auto;padding:20px 18px 40px}.ref-grid{display:grid;grid-template-columns:1fr 1fr;gap:22px 12px}.ref-cell{text-align:center;font-family:var(--font-question)}.ref-fig{width:100%;max-width:150px;height:auto}.ref-var{font-family:var(--font-question);font-style:italic;font-size:12px;fill:currentColor}.ref-small{font-family:var(--font-question);font-size:7px;fill:currentColor}.ref-special{margin:22px 0}.ref-special .ref-fig{max-width:330px}.ref-caption{font-weight:700;font-family:var(--font-question)}.ref-note{font-family:var(--font-question);font-size:15px;line-height:1.45;margin:16px 0 0}.desmos{position:fixed;background:#fff;border:1px solid var(--bb-border-strong);box-shadow:0 10px 34px #0000004d;display:flex;flex-direction:column;z-index:60}.desmos-bar{display:flex;align-items:center;justify-content:space-between;background:#1a1a1a;color:#fff;padding:6px 10px}.desmos-tabs .is-active{background:#fff;color:#1a1a1a;border-radius:3px;padding:3px 10px;font-size:13px;font-weight:700}.desmos-grip{background:none;border:0;color:#fff;cursor:grab}.desmos-grip:active{cursor:grabbing}.desmos-close{background:none;border:0;color:#fff;cursor:pointer}.desmos-graph{flex:1;min-height:0}.desmos-error{padding:26px;font-size:14px;color:var(--bb-text-muted)}.desmos-resize{position:absolute;right:2px;bottom:2px;background:none;border:0;cursor:nwse-resize;color:var(--bb-text-muted)}.results{max-width:1080px;margin:0 auto;padding:34px 26px 70px}.results h1{font-weight:300;font-size:2.5rem;letter-spacing:-1.5px;margin:0 0 6px}.results-sub{margin:0 0 24px;color:var(--bb-text-muted)}.results-stats{display:flex;gap:18px;margin-bottom:28px}.stat{flex:1;background:var(--bb-header-bg);border-radius:var(--radius-card);padding:20px;text-align:center}.stat-n{font-size:38px;font-weight:700}.stat-l{font-size:15px;font-weight:700}.results-controls{display:flex;align-items:center;justify-content:space-between;margin-bottom:14px}.results-filter{display:inline-flex;border:1px solid var(--bb-border-strong);border-radius:6px;overflow:hidden}.results-filter button{border:0;background:#fff;padding:6px 16px;font-size:14px;cursor:pointer}.results-filter button+button{border-left:1px solid var(--bb-border-strong)}.results-filter button.is-on{background:#29292b;color:#fff}.results-table{width:100%;border-collapse:collapse;font-size:15px}.results-table th{background:#4a4a4a;color:#fff;text-align:left;padding:12px 14px;font-size:14px}.results-table td{padding:12px 14px;border-bottom:1px solid var(--bb-border)}.results-table tr:nth-child(odd) td{background:#fafafa}.is-omitted{color:var(--bb-flag)}.is-wrong{color:var(--bb-flag);font-weight:700}.is-right{color:#1d7846;font-weight:700}.pill{display:inline-flex;align-items:center;gap:5px;border-radius:var(--radius-pill);padding:3px 11px;font-size:13px;font-weight:700}.pill-right{background:#c9dfd3;color:#1d7846}.pill-wrong{background:#eacace;color:var(--bb-flag)}.results-foot{margin-top:28px}.player-boot{display:grid;place-items:center;height:100vh;gap:16px}mjx-container{font-size:inherit!important}mjx-container[display=true]{margin:.6em 0!important}@media (prefers-reduced-motion: reduce){.spinner span{animation:none}}.results-table tr.is-clickable{cursor:pointer}.results-table tr.is-clickable:hover{background:var(--bb-page-bg)}.results-table tr.is-clickable:focus-visible{outline:2px solid var(--bb-focus);outline-offset:-2px}.results-table tr.is-clickable .results-qnum{font-weight:700}.results-table tr.is-clickable:hover .results-qnum{color:var(--bb-blue)}.ans-letter{font-family:var(--font-ui);font-weight:700}.ans-omitted{font-family:var(--font-ui)}.qreview-scrim{position:fixed;top:0;right:0;bottom:0;left:0;background:#00000073;display:grid;grid-template-rows:minmax(0,1fr);grid-template-columns:minmax(0,1fr);place-items:center;padding:24px;z-index:120}.qreview{background:#fff;border-radius:10px;box-shadow:0 2px 10px #00000029;width:min(860px,100%);max-height:100%;display:flex;flex-direction:column}.qreview-bar{display:flex;align-items:center;gap:14px;padding:14px 18px;border-bottom:1px solid var(--bb-border);font-family:var(--font-ui)}.qreview-where{font-size:15px;font-weight:700}.qreview-spacer{flex:1}.qreview-close{background:none;border:0;cursor:pointer;line-height:0}.qreview-body{padding:20px 26px 26px;overflow:auto;min-height:0}.qreview-foot{display:flex;align-items:center;gap:16px;justify-content:flex-end;padding:12px 18px;border-top:1px solid var(--bb-border);background:var(--bb-header-bg);border-radius:0 0 10px 10px}.qreview-count{font-family:var(--font-ui);font-size:14px;margin-right:auto;padding-left:8px}.qreview-foot .btn:disabled{opacity:.45;cursor:default}.choice.is-static{cursor:default}.choice.is-key{border-color:#1a7f43;box-shadow:inset 0 0 0 1px #1a7f43}.choice.is-key .choice-letter{background:#1a7f43;border-color:#1a7f43;color:#fff}.choice.is-yours-wrong{border-color:var(--bb-flag);box-shadow:inset 0 0 0 1px var(--bb-flag)}.choice.is-yours-wrong .choice-letter{background:var(--bb-flag);border-color:var(--bb-flag);color:#fff}.choice-tag{margin-left:auto;padding-left:14px;font-family:var(--font-ui);font-size:12px;font-weight:700;white-space:nowrap;color:var(--bb-text-muted)}.choice.is-key .choice-tag{color:#1a7f43}.choice.is-yours-wrong .choice-tag{color:var(--bb-flag)}.qreview-spr{display:flex;gap:40px;margin-top:18px}.qreview-spr>div{display:flex;flex-direction:column;gap:4px}.qreview-spr-l{font-family:var(--font-ui);font-size:12px;font-weight:700;text-transform:uppercase;letter-spacing:.04em;color:var(--bb-text-muted)}.qreview-meta{margin-top:22px;padding-top:14px;border-top:1px solid var(--bb-border);font-family:var(--font-ui);font-size:13px;color:var(--bb-text-muted)}.qreview-video{margin-top:22px;padding-top:14px;border-top:1px solid var(--bb-border)}.qreview-video-toggle{display:inline-flex;align-items:center;gap:8px;padding:8px 14px;border:1px solid var(--bb-border);border-radius:6px;background:#fff;font-family:var(--font-ui);font-size:13px;font-weight:700;color:var(--bb-blue);cursor:pointer}.qreview-video-toggle:hover{background:#f4f7fc}.qreview-video-arrow{transition:transform .15s ease}.qreview-video-toggle[aria-expanded=true] .qreview-video-arrow{transform:rotate(90deg)}.qreview-video-stack{margin-top:14px;display:flex;flex-direction:column;gap:20px;max-width:560px}.qreview-video-label{margin-bottom:6px;font-family:var(--font-ui);font-size:12px;font-weight:700;text-transform:uppercase;letter-spacing:.04em;color:var(--bb-text-muted)}.qreview-video-embed{position:relative;width:100%;aspect-ratio:16 / 9;border-radius:6px;overflow:hidden;background:#000}.qreview-video-embed iframe{position:absolute;top:0;right:0;bottom:0;left:0;width:100%;height:100%;border:0}.book{min-height:100%;display:flex;flex-direction:column;background:var(--bb-page-bg)}.book-head{position:sticky;top:0;z-index:20;background:var(--bb-header-bg);border-bottom:1px solid var(--bb-border-strong);padding:14px 32px 12px}.book-head-top{display:flex;align-items:flex-start;gap:20px;max-width:900px;margin:0 auto}.book-back{flex:none;display:inline-flex;align-items:center;gap:4px;border:1px solid var(--bb-border-strong);background:#fff;border-radius:var(--radius-pill);padding:6px 14px 6px 8px;font-size:14px;font-weight:600;color:var(--bb-text);cursor:pointer;margin-top:2px}.book-back:hover{background:var(--bb-page-bg-tint)}.book-title{flex:1;min-width:0}.book-title h1{margin:0;font-size:22px;font-weight:700;letter-spacing:-.3px;color:var(--bb-blue)}.book-source{margin:2px 0 0;font-size:12.5px;color:var(--bb-text-muted)}.book-jump{flex:none;display:inline-flex;align-items:center;gap:6px;font-size:13px;color:var(--bb-text-muted);margin-top:2px}.book-jump input{width:56px;padding:5px 8px;border:1px solid var(--bb-border-strong);border-radius:5px;font:inherit;font-size:14px}.book-jump button{border:1px solid var(--bb-border-strong);background:#fff;border-radius:5px;padding:5px 12px;font:inherit;font-size:13px;font-weight:600;cursor:pointer}.book-jump button:hover{background:var(--bb-page-bg-tint)}.book-filters{display:flex;flex-wrap:wrap;gap:8px;max-width:900px;margin:12px auto 0}.book-filters button{display:inline-flex;align-items:center;gap:7px;border:1px solid var(--bb-border-strong);background:#fff;border-radius:var(--radius-pill);padding:6px 14px;font-size:13.5px;font-weight:600;color:var(--bb-text);cursor:pointer}.book-filters button:hover:not(:disabled){border-color:var(--bb-blue)}.book-filters button.is-on{background:var(--bb-blue);border-color:var(--bb-blue);color:#fff}.book-filters button:disabled{opacity:.45;cursor:default}.book-count{font-size:12px;font-weight:700;padding:1px 7px;border-radius:var(--radius-pill);background:var(--bb-page-bg);color:var(--bb-text-muted)}.book-filters button.is-on .book-count{background:#ffffff3d;color:#fff}.book-body{flex:1;width:100%;max-width:820px;margin:0 auto;padding:26px 24px 96px}.book-chapter{display:flex;align-items:baseline;justify-content:space-between;gap:12px;margin:8px 0 18px;padding-bottom:8px;border-bottom:2px solid var(--bb-border-strong);font-family:var(--font-ui);font-size:19px;font-weight:700;letter-spacing:-.2px;color:var(--bb-blue);scroll-margin-top:132px}.book-chapter-block+.book-chapter-block .book-chapter{margin-top:34px}.book-chapter-count{flex:none;font-size:12px;font-weight:600;color:var(--bb-text-muted)}.book-foot-ch{color:var(--bb-text-muted);font-weight:600}.bq{background:var(--bb-card-bg);border:1px solid var(--bb-border);border-radius:var(--radius-card);box-shadow:var(--shadow-card);padding:22px 26px 18px;margin-bottom:22px;font-family:var(--font-question);font-size:17px;line-height:1.5;scroll-margin-top:132px}.bq-head{display:flex;align-items:baseline;flex-wrap:wrap;gap:6px 14px}.bq-num{flex:none;font-family:var(--font-ui);font-weight:700;font-size:20px;color:var(--bb-text)}.bq-exam{flex:none;font-family:var(--font-ui);font-size:12.5px;font-weight:700;letter-spacing:.2px;color:var(--bb-text)}.bq-tags{font-family:var(--font-ui);font-size:12px;font-weight:600;letter-spacing:.1px;color:var(--bb-text-muted);text-transform:none}.bq-rule{height:1px;background:var(--bb-border);margin:10px 0 16px}.bq .q-prompt{margin:0 0 16px}.bq .q-stimulus{margin:14px 0}.bq-choices{margin-top:4px}.choice.choice-static{cursor:default;background:transparent}.choice.choice-static:hover{border-color:var(--bb-border-strong)}.bq-spr{font-family:var(--font-ui);font-size:12.5px;font-style:italic;color:var(--bb-text-muted);margin:4px 0 0}.bq-answer{margin-top:16px;border-top:1px dashed var(--bb-border-strong);padding-top:10px;font-family:var(--font-ui)}.bq-answer summary{cursor:pointer;font-size:13px;font-weight:600;color:var(--bb-blue);list-style:none;-webkit-user-select:none;user-select:none}.bq-answer summary::-webkit-details-marker{display:none}.bq-answer summary:before{content:"▸ "}.bq-answer[open] summary:before{content:"▾ "}.bq-answer-body{margin-top:8px;font-size:15px;color:var(--bb-text)}.book-end{text-align:center;font-family:var(--font-ui);font-size:13px;color:var(--bb-text-muted);padding:8px 0 0}.book-foot{position:sticky;bottom:0;z-index:20;display:flex;align-items:center;justify-content:space-between;gap:16px;background:#fff;border-top:1px solid var(--bb-border-strong);padding:10px 32px;font-family:var(--font-ui)}.book-foot-pos{font-size:14px;font-weight:600}.book-foot button{display:inline-flex;align-items:center;gap:4px;border:1px solid var(--bb-border-strong);background:#fff;border-radius:var(--radius-pill);padding:5px 14px 5px 10px;font:inherit;font-size:13px;font-weight:600;cursor:pointer}.book-foot button:hover{background:var(--bb-page-bg-tint)}@media (max-width: 640px){.book-head-top{flex-wrap:wrap}.book-jump{order:3}}