:root{color-scheme:light;--navy:#101b2a;--ink:#18273a;--muted:#576679;--line:#d4dce5;--paper:#f2f5f8;--yellow:#f5cb51;--green:#136544;--red:#9c2835}*{box-sizing:border-box}body{margin:0;background:var(--paper);color:var(--ink);font-family:Inter,ui-sans-serif,system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;font-size:16px;line-height:1.55}button,input,select{font:inherit}button{cursor:pointer}button:disabled{cursor:not-allowed;opacity:.5}button:focus-visible,a:focus-visible,select:focus-visible,input:focus-visible{outline:3px solid #397cce;outline-offset:4px}button{transition:background .15s,border-color .15s}button:hover:not(:disabled){filter:brightness(.97)}.skip{position:absolute;left:12px;top:-70px;padding:10px;background:white;z-index:3}.skip:focus{top:10px}.masthead{background:var(--navy);color:white;border-top:5px solid var(--yellow);padding:23px max(24px,calc((100vw - 1200px)/2));display:flex;align-items:center;justify-content:space-between;gap:25px}.brand{color:white;background:none;border:0;display:flex;gap:13px;align-items:center;text-align:left;font-size:17px;font-weight:800;letter-spacing:.08em;padding:0}.mark{display:grid;place-items:center;background:var(--yellow);color:var(--navy);width:48px;height:48px;border-radius:4px;letter-spacing:-.07em;font-size:21px}.brand-sub{display:block;font-size:12px;letter-spacing:.25em;color:#becad9;font-weight:600}.book{text-align:right;font-size:13px;letter-spacing:.09em;color:#d0d9e4}.book span{display:block;font-size:12px;color:#92a5bb;margin-top:3px}main{max-width:1200px;padding:38px 24px 68px;margin:auto;min-height:70vh}h1,h2,h3,p{margin-top:0}h1{font-size:clamp(28px,4vw,40px);line-height:1.16;letter-spacing:-.035em;margin-bottom:10px}h2{font-size:23px;line-height:1.3;letter-spacing:-.02em}h3{font-size:18px;line-height:1.4}.eyebrow{font-size:12px;letter-spacing:.13em;font-weight:750;text-transform:uppercase;color:var(--muted);margin-bottom:9px}.muted{color:var(--muted)}.home-head{display:flex;justify-content:space-between;align-items:center;gap:30px;margin-bottom:25px}.home-head p{margin-bottom:0;max-width:650px}.stats{display:flex;gap:28px;flex-shrink:0}.stats b{display:block;font-size:29px;letter-spacing:-.04em}.stats span{font-size:13px;color:var(--muted)}.setup{display:grid;grid-template-columns:1.2fr 1fr;gap:22px;margin-bottom:33px}.panel{background:white;border:1px solid var(--line);border-radius:10px;padding:24px}.mode-group{display:flex;gap:8px;margin-bottom:12px}.mode{flex:1;background:white;border:1px solid #bdc9d7;border-radius:6px;padding:10px 15px;color:var(--ink);font-weight:650}.mode[aria-pressed=true]{background:var(--navy);color:white;border-color:var(--navy)}.panel p{font-size:14px;margin-bottom:0;color:var(--muted)}.mode-panel h2,.mixed-panel h2{font-size:18px;margin-bottom:15px}.mixed-panel{background:#e7edf4;border-color:#c8d4e2}.mixed-controls{display:flex;gap:10px;align-items:center}.mixed-controls select{width:100%;background:white;border:1px solid #b8c6d6;border-radius:6px;padding:11px;color:var(--ink)}.mixed-panel p{margin-top:12px}.primary,.secondary,.text-button{border-radius:6px;padding:11px 20px;font-weight:700;white-space:normal}.primary{background:var(--yellow);color:#172435;border:1px solid #e2b634}.secondary{background:white;border:1px solid #b8c6d6;color:var(--ink)}.text-button{background:none;border:0;color:var(--muted);padding-left:0}.mixed-controls .primary{min-width:152px}.section-line{display:flex;align-items:baseline;justify-content:space-between;gap:20px;margin-bottom:14px}.section-line h2{margin:0}.section-line span{font-size:14px;color:var(--muted)}.chapter-grid{display:grid;grid-template-columns:1fr 1fr;gap:10px}.chapter-card{display:flex;align-items:center;gap:16px;text-align:left;background:white;border:1px solid var(--line);border-radius:7px;padding:17px 19px;color:var(--ink);min-height:97px}.chapter-card:hover{border-color:#708aa8;box-shadow:0 3px 10px #15243c08}.chapter-num{font-size:14px;font-weight:750;font-variant-numeric:tabular-nums;color:#5b6f88;background:#edf2f7;width:36px;height:36px;display:grid;place-items:center;flex-shrink:0;border-radius:4px}.chapter-copy{flex:1}.chapter-copy strong{display:block;font-size:16px;font-weight:650;line-height:1.4}.chapter-copy small{font-size:12px;color:var(--muted);display:block;margin-top:5px}.chapter-start{font-size:14px;font-weight:650;color:#49617b}.session{max-width:870px;margin:auto}.session-top{display:flex;justify-content:space-between;align-items:center;gap:15px;margin-bottom:18px}.pill{background:#e4ebf3;color:#34516e;border:1px solid #ccd8e5;border-radius:4px;padding:5px 10px;font-size:12px;font-weight:750;letter-spacing:.04em;text-transform:uppercase}.session-title{font-size:25px;line-height:1.3;margin:0 0 23px}.progress-label{display:flex;justify-content:space-between;gap:10px;font-size:14px;color:var(--muted);margin-bottom:8px}progress{width:100%;height:6px;border:0;border-radius:5px;background:#dce4ec;display:block;margin-bottom:25px}progress::-webkit-progress-bar{background:#dce4ec;border-radius:5px}progress::-webkit-progress-value{background:#577ca0;border-radius:5px}progress::-moz-progress-bar{background:#577ca0}.question-card{background:white;border:1px solid var(--line);border-radius:10px;padding:32px}.chapter-context{font-size:13px;color:#586f87;margin-bottom:12px}.prompt{font-size:23px;line-height:1.48;letter-spacing:-.02em;margin-bottom:25px;font-weight:650}.options{padding:0;margin:0;border:0;display:grid;gap:10px;min-width:0}.option{display:flex;gap:13px;align-items:flex-start;border:1px solid #cbd5e1;border-radius:7px;padding:15px 17px;cursor:pointer;line-height:1.5}.option:has(input:checked){background:#edf3fc;border-color:#517db4;box-shadow:inset 0 0 0 1px #517db4}.option input{position:absolute;opacity:0;width:1px;height:1px}.option:has(input:focus-visible){outline:3px solid #397cce;outline-offset:3px}.option-letter{height:28px;min-width:28px;border:1px solid #c8d4e1;border-radius:4px;display:grid;place-items:center;font-size:13px;font-weight:700;color:#637a93;background:#f5f7fa}.option:has(input:checked) .option-letter{background:#355c88;border-color:#355c88;color:white}.option.correct{border-color:#49896a;background:#edf8f1;box-shadow:none}.option.wrong{border-color:#bb6871;background:#fff1f2;box-shadow:none}.option-text{flex:1}.answer-indicator{font-size:12px;font-weight:700;display:block;margin-top:4px}.correct .answer-indicator{color:var(--green)}.wrong .answer-indicator{color:var(--red)}.feedback{padding:21px 23px;border-left:4px solid var(--green);background:#edf7f1;border-radius:0 5px 5px 0;margin-top:22px}.feedback.incorrect{background:#fff2f1;border-left-color:var(--red)}.feedback h3{margin-bottom:7px}.feedback p{margin-bottom:12px}.source{font-size:13px;color:var(--muted);margin-bottom:0!important}.quiz-actions{display:flex;align-items:center;justify-content:space-between;gap:14px;margin-top:24px}.keyboard{font-size:12px;color:var(--muted);margin:16px 0 0;text-align:center}.sr{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}.result-hero{display:grid;grid-template-columns:auto 1fr;align-items:center;gap:30px;background:var(--navy);color:white;padding:32px;border-radius:10px;margin:15px 0 24px}.score{font-size:56px;font-weight:750;letter-spacing:-.05em;color:var(--yellow);line-height:1}.score small{display:block;color:#b5c4d6;font-size:14px;letter-spacing:0;font-weight:500;margin-top:12px}.result-hero p{color:#c7d2df;margin-bottom:0}.result-hero h1{font-size:29px}.actions{display:flex;gap:10px;flex-wrap:wrap;margin:20px 0 28px}.review-list{display:grid;gap:12px}.review{border:1px solid var(--line);border-radius:7px;background:white;overflow:hidden}.review summary{cursor:pointer;padding:19px;display:flex;align-items:baseline;gap:12px;font-weight:600;list-style:none}.review summary::-webkit-details-marker{display:none}.review summary:before{content:'+';font-size:20px;line-height:1;color:#526c88}.review[open] summary:before{content:'−'}.review-status{font-size:12px;font-weight:750;color:var(--green);white-space:nowrap}.review-status.bad{color:var(--red)}.review-body{padding:0 22px 22px}.review-body p{margin:0 0 10px}.review-answer{background:#edf7f1;padding:12px;border-radius:5px}.review-chapter{font-size:13px;color:var(--muted);font-weight:500;display:block;margin-bottom:4px}.review-tabs{display:flex;gap:8px;margin:12px 0 18px}.review-tabs button{padding:8px 14px;border-radius:5px;border:1px solid #bdc9d7;background:white;color:var(--ink);font-size:14px}.review-tabs button[aria-pressed=true]{background:#dfe9f5;border-color:#708da9}.empty{padding:25px;background:white;border:1px solid var(--line);border-radius:8px}.question-nav{display:flex;gap:6px;flex-wrap:wrap;margin:20px 0}.question-nav button{border:1px solid #bdcbd9;border-radius:4px;padding:4px 8px;background:white;color:#365675;font-size:13px;min-width:30px}.question-nav button.active{background:var(--navy);color:white}.question-nav button.answered:not(.active){background:#e1ebf6}.exam-note{font-size:14px;color:var(--muted)}footer{max-width:1200px;margin:auto;border-top:1px solid var(--line);padding:22px 24px 35px;display:flex;justify-content:space-between;gap:20px;color:#637285;font-size:12px}dialog{border:1px solid #bfcbd9;border-radius:10px;padding:28px;max-width:450px;color:var(--ink)}dialog::backdrop{background:#101b2aa6}dialog .actions{margin-bottom:0}dialog h2{margin-bottom:10px}@media(max-width:760px){.masthead{padding:17px 20px}.book{display:none}main{padding:25px 18px 45px}.home-head{display:block}.stats{margin-top:22px;gap:30px}.stats b{font-size:25px}.setup{grid-template-columns:1fr;gap:12px}.chapter-grid{grid-template-columns:1fr}.panel{padding:20px}.chapter-card{min-height:90px;padding:15px}.chapter-start{display:none}.question-card{padding:23px 19px}.prompt{font-size:20px}.option{padding:13px 12px}.keyboard{display:none}.result-hero{padding:25px;gap:20px}.score{font-size:43px}.result-hero h1{font-size:24px}.session-title{font-size:21px}.section-line span{font-size:12px}.quiz-actions .primary{padding:11px 14px}footer{display:block}footer span{display:block;margin-bottom:7px}.review summary{padding:16px;font-size:15px}.review-status{white-space:normal}.mixed-controls .primary{min-width:130px}}@media(prefers-reduced-motion:reduce){*{transition:none!important}}@media(max-width:390px){.mixed-controls{align-items:stretch;flex-direction:column}.result-hero{grid-template-columns:1fr}.quiz-actions{flex-wrap:wrap}.option-letter{min-width:24px;width:24px;height:24px}}

/* Textbook evidence is disclosed only with the checked answer or final review. */
.textbook-evidence{margin-top:22px;border:1px solid #c8d2df;border-radius:12px;background:#fff;color:#172536;overflow:hidden}
.textbook-evidence>summary{cursor:pointer;padding:16px 18px;font-weight:750;font-size:1rem;line-height:1.5}
.textbook-evidence>summary span{display:inline-block;margin-left:8px;font-size:.72rem;color:#53657a;font-weight:500}
.textbook-evidence[open]>summary{background:#fff7d9;border-bottom:1px solid #dfd4af}
.textbook-evidence summary:focus-visible,.textbook-image-link:focus-visible{outline:3px solid #3276c7;outline-offset:-3px}
.textbook-content{padding:18px}.textbook-book{font-weight:700;margin:0 0 8px}.textbook-note{font-size:.85rem;line-height:1.6;color:#53657a}
.textbook-passage{margin:22px 0;border-top:1px solid #dde3ec;padding-top:16px}.textbook-passage figcaption{display:flex;flex-wrap:wrap;gap:5px 18px;align-items:baseline;margin-bottom:12px}.textbook-passage figcaption span{font-size:.78rem;color:#586a7d}
.textbook-image-link{display:block;max-width:700px;background:#fff}.textbook-passage img{display:block;width:100%;height:auto;border:1px solid #eee;border-radius:3px}
.passage-text{margin-top:12px}.passage-text summary{font-size:.85rem;cursor:pointer;color:#315c87;padding:6px 0}.passage-text blockquote{margin:12px 0;font-family:Georgia,serif;line-height:1.8;font-size:1rem}.passage-text mark{background:#fff1a5;color:#253141;box-decoration-break:clone;-webkit-box-decoration-break:clone;padding:2px 3px}
@media(max-width:560px){.textbook-content{padding:12px}.textbook-evidence>summary{padding:13px}.textbook-evidence>summary span{display:block;margin-left:0}}

.full-page-link{display:inline-block;margin-top:12px;color:#285b8a;font-weight:700;font-size:.9rem;padding:8px 0}.textbook-image-link{cursor:zoom-in;max-width:850px}.textbook-image-link img{box-shadow:0 2px 10px #15243a18}

.prompt{white-space:pre-line}

.book-picker{margin:2rem 0 0}.book-picker h2{font-size:1rem;margin-bottom:.8rem}.book-options{display:grid;grid-template-columns:1fr 1fr;gap:1rem}.book-options button{text-align:left;padding:1.1rem 1.2rem;border:2px solid #c6d0dc;border-radius:10px;background:white;color:#101b2a;cursor:pointer;font:inherit}.book-options button[aria-pressed="true"]{border-color:#101b2a;background:#101b2a;color:white;box-shadow:inset 5px 0 #f5cb51}.book-options strong{display:block;font-size:1.1rem;line-height:1.4}.book-options span{display:block;font-size:.9rem;margin-top:.5rem}.session-book{font-size:.9rem;color:#53647a;margin:1.5rem 0 .4rem}.book-options button:focus-visible{outline:3px solid #c18400;outline-offset:3px}@media(max-width:620px){.book-options{grid-template-columns:1fr}.book-picker{margin-top:1.2rem}}