:root{--bg:#f7f8f4;--ink:#1d332f;--muted:#6f7f78;--line:#e0e6df;--green:#176448;--lime:#d9ef9c;--white:#fff;--orange:#d28b55}*{box-sizing:border-box}body{margin:0;background:var(--bg);color:var(--ink);font:14px 'DM Sans',system-ui,sans-serif}button,input,select{font:inherit}button,a,input,select{-webkit-tap-highlight-color:transparent}button{cursor:pointer}button:focus-visible,a:focus-visible,input:focus-visible,select:focus-visible{outline:3px solid #4a946f;outline-offset:4px}button{border:0}a{color:inherit}h1,h2,h3{font-family:'Manrope',system-ui,sans-serif;letter-spacing:-.04em}h1{font-size:38px;font-weight:700;margin:10px 0 12px;line-height:1.18}h2{font-size:23px;margin:0}h3{font-size:18px;margin:0 0 9px}p{line-height:1.7}.sidebar{position:fixed;inset:0 auto 0 0;width:234px;background:#fff;border-right:1px solid var(--line);padding:30px 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/* Chapter practice and time-based simulation controls. */
.sidebar{overflow-y:auto}.nav-label{margin-top:26px}.side-bottom{padding-top:22px}.bank-toolbar{display:flex;justify-content:space-between;gap:16px;margin-bottom:20px;align-items:center}.segmented{display:flex;padding:5px;background:#e9eee2;border-radius:9px;gap:4px}.segmented button{background:none;padding:12px 18px;border-radius:6px;color:#64765d;font-weight:600;font-size:12px}.segmented .selected{background:#fff;color:var(--ink);box-shadow:0 2px 6px #15341d0c}.segmented span{margin-left:8px;font-size:10px;color:#8a9a7f}.bank-layout{display:grid;grid-template-columns:310px minmax(0,1fr);gap:22px;align-items:start}.bank-browser{padding:20px;position:sticky;top:20px}.bank-browser select,.bank-browser .search{width:100%;margin-top:12px;font-size:11px}.bank-list-meta{font-size:10px;color:var(--muted);display:flex;justify-content:space-between;margin:20px 0 10px}.bank-list{max-height:540px;overflow:auto;margin:0 -10px;scrollbar-width:thin}.bank-item{display:flex;width:100%;gap:11px;align-items:center;background:transparent;text-align:left;padding:13px 10px;border-radius:7px;color:#586e5d}.bank-item.selected{background:#eaf1e2;color:var(--ink)}.bank-item:hover{background:#f0f4ea}.bank-item-number{font-size:9px;color:#85977c}.bank-item b{font-size:11px;line-height:1.5;display:block}.bank-item small{display:block;font-size:10px;color:#8a9883;margin-top:3px}.solved-mark{margin-left:auto;color:#628950}.bank-work{padding:30px;min-height:630px;display:flex;flex-direction:column}.problem-id{font-size:10px;color:#83967c;margin:9px 0 14px}.bank-prompt{font-size:17px;line-height:1.85;color:#355340;padding:20px 0 10px;margin:0;white-space:pre-line}.bank-bottom{margin-top:auto;padding-top:28px}.bank-bottom .row{padding-top:18px;border-top:1px solid var(--line);margin-top:20px}.bank-work .input-wrap input{font-size:19px}.bank-work .feedback{font-size:13px;line-height:1.9}.btn:disabled{opacity:.4;cursor:default}.textbook-note{border-left:3px solid #bccca4;padding:8px 20px;margin-top:25px}.textbook-note p{color:var(--muted);font-size:12px;max-width:850px}.textbook-grid{display:grid;gap:18px}.textbook-card{display:flex;gap:25px;align-items:center}.textbook-card h2{margin-top:10px;font-size:21px}.textbook-card p{color:var(--muted);font-size:12px;max-width:650px}.book-cover{min-width:110px;height:145px;background:#204d3b;color:#d9e8be;border-radius:3px 9px 9px 3px;box-shadow:inset 5px 0 0 #163f2d;display:flex;align-items:center;justify-content:center;flex-direction:column;padding:12px}.book-cover span{font:italic 56px Georgia}.book-cover small{font-size:7px;letter-spacing:.12em;text-align:center;margin-top:16px}.book-links{display:flex;gap:18px;flex-wrap:wrap}.book-links a{font-size:11px;color:var(--green)}.sim-controls{margin:10px 0 22px;padding:0 0 20px;border-bottom:1px solid var(--line)}.sim-buttons{display:flex;gap:6px;flex-wrap:wrap}.sim-buttons .btn{padding:9px 12px;font-size:10px;min-height:36px}.sim-speed{font-size:10px;color:var(--muted);display:flex;gap:7px;align-items:center}.sim-speed select{padding:7px;font-size:10px}.sim-scrub{margin:18px 0 12px}.sim-readouts{background:#edf3e6;border:1px solid #dce7d3;display:flex;gap:12px;justify-content:space-between;border-radius:7px;padding:13px;font-size:10px;color:#819471;margin-bottom:12px}.sim-readouts b{display:block;font-size:13px;color:#325139;margin-top:3px}.sim-assist{font-size:9px;margin-top:7px}.lab svg{height:auto;max-height:320px}.lab .sim-large{font-size:25px}.sr-only{position:absolute;width:1px;height:1px;padding:0;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}.practice-grid .panel-title{flex-wrap:wrap}.practice-grid .panel-title select{font-size:11px}.bank-work #bank-solution{text-align:left;padding-top:12px;align-self:flex-start}
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@media(max-width:800px){.bank-layout{grid-template-columns:1fr}.bank-browser{position:static}.bank-list{max-height:220px}.bank-work{min-height:550px}.bank-toolbar{flex-wrap:wrap}.bank-prompt{font-size:16px}.textbook-card{gap:16px}.book-cover{min-width:85px;width:85px;height:120px}.book-cover span{font-size:44px}.sidebar nav{flex-wrap:wrap}.sidebar .nav{width:auto;flex:1 0 29%}.bank-work .row .eyebrow{line-height:1.7}.sim-controls>.row{flex-wrap:wrap}.segmented{width:100%}.segmented button{flex:1}.bank-toolbar>.btn{width:100%}}
.reader-layout{display:grid;grid-template-columns:280px minmax(0,1fr);gap:22px;align-items:start}.reader-sidebar{padding:18px;position:sticky;top:20px}.reader-mode{margin-bottom:20px}.reader-mode button{padding:9px 10px;font-size:10px;flex:1}.reader-sidebar select,.reader-sidebar .search{width:100%;font-size:11px;margin:9px 0}.reader-section-list{max-height:450px;overflow:auto;scrollbar-width:thin}.reader-help{margin-top:20px;border-top:1px solid var(--line);padding-top:15px}.reader-help p{margin-top:12px;font-size:10px}.reader-content{min-width:0}.reader-toolbar{display:flex;align-items:center;gap:7px;flex-wrap:wrap;background:#fff;border:1px solid var(--line);padding:12px;border-radius:9px}.reader-toolbar .btn{padding:8px 12px;min-height:34px}.reader-toolbar form{display:flex;gap:7px;align-items:center;font-size:11px}.reader-toolbar input{width:70px;border:1px solid var(--line);padding:8px;border-radius:5px}.reader-open{margin-left:auto;font-size:10px;color:var(--green)}.reader-location{font-size:10px;color:var(--muted);margin:12px 2px}.pdf-frame{width:100%;height:850px;border:1px solid var(--line);border-radius:9px;background:#e7ebe1}.reader-notes{margin-top:18px;padding:20px}.reader-notes textarea{width:100%;border:1px solid var(--line);background:#fcfdf9;border-radius:7px;padding:13px;margin-top:12px;font:13px 'DM Sans',sans-serif;line-height:1.8;color:var(--ink);resize:vertical}.reader-notes .row{margin-bottom:10px}.source-cite{color:#366b4d;line-height:1.8;font-size:11px;text-decoration:underline;text-underline-offset:3px}.lab-source{border-left:2px solid #bccca4;padding:0 12px;margin-bottom:18px}.lab-source p{font-size:10px;margin-top:6px}.uploaded-cover{width:120px;max-height:180px;object-fit:contain;border-radius:4px;box-shadow:0 5px 15px #17372f19}.reader-sidebar #reader-search-results{max-height:300px;overflow:auto;scrollbar-width:thin}.book-links button{font-size:11px}.reader-content .badge{font-size:8px}.sidebar nav .nav{padding-top:9px;padding-bottom:9px}
@media(max-width:1100px){.reader-layout{grid-template-columns:230px minmax(0,1fr)}.reader-open{width:100%;margin:4px 0}.pdf-frame{height:740px}.reader-toolbar form label{display:none}}
@media(max-width:850px){.reader-layout{grid-template-columns:1fr}.reader-sidebar{position:static}.reader-section-list{max-height:200px}.pdf-frame{height:700px}.uploaded-cover{width:88px}.textbook-card{align-items:flex-start}.reader-content .row{flex-wrap:wrap}.reader-toolbar form label{display:block}}
.subject-practice-summary{display:flex;align-items:center;gap:32px;padding:18px 22px;border:1px solid var(--line);background:#fff;border-radius:10px;margin-bottom:23px}.subject-practice-summary>div{display:flex;align-items:center;gap:10px}.subject-practice-summary strong{font:700 25px Manrope,system-ui;color:#365b3b}.subject-practice-summary span{font-size:10px;color:var(--muted);max-width:85px;line-height:1.5}.subject-practice-summary .btn{margin-left:auto}.interactive-filter{display:flex;align-items:center;gap:8px;font-size:10px;color:#617455;margin-top:14px;cursor:pointer}.interactive-filter input{accent-color:#477746;width:14px;height:14px}.interactive-tag{color:#4d7841;font-weight:600;white-space:nowrap}.bank-item-number{max-width:48px;min-width:20px;font-size:9px;overflow-wrap:anywhere}.problem-reference{font-size:10px;color:#8b9a81;padding-top:3px}.problem-reference summary{cursor:pointer}.problem-reference .source-cite{margin-top:10px}.inline-experiment{padding:19px;background:#f4f7ef;border:1px solid #dbe5d2;border-radius:11px;margin:10px 0 14px}.inline-experiment .eyebrow{color:#6c8a5b;font-size:8px}.inline-experiment h3{margin:7px 0 0;font-size:17px}.inline-experiment>.plain-note{margin:12px 0 0;font-size:11px;line-height:1.7}.inline-experiment svg{width:100%;height:auto;display:block;margin:12px 0}.inline-experiment svg text{font:12px 'DM Sans',system-ui;fill:#566d4f}.experiment-actions .control{display:flex;align-items:center;gap:8px;flex:1;max-width:230px}.experiment-actions input{margin-top:0;min-width:70px}.experiment-readout{display:flex;gap:12px;flex-wrap:wrap;font-size:11px;line-height:1.6;color:#416136;padding:10px 0 0;min-height:29px}.experiment-readout span{padding:5px 8px;background:#e5eddc;border-radius:4px}.inline-experiment .experiment-note{font-size:9px;margin-top:7px;color:#8b9981}.practice-source-note{font-size:10px;color:#8e9c86;line-height:1.8;margin:23px 0}.selection-note{margin-bottom:12px;padding:8px 11px;border-left:2px solid #becfad}.bank-work{min-height:630px}.bank-prompt{font-size:17px;line-height:1.9}.bank-work .problem-id{color:#8c9a83;font-size:9px}.inline-experiment .row{gap:12px}.inline-experiment .badge{font-size:8px}
@media(max-width:1100px){.subject-practice-summary{gap:18px;flex-wrap:wrap}.subject-practice-summary>div{gap:7px}.subject-practice-summary .btn{margin-left:0}.experiment-actions{flex-wrap:wrap}.experiment-actions .control{max-width:none;width:100%}.bank-layout{grid-template-columns:250px minmax(0,1fr)}}
@media(max-width:800px){.subject-practice-summary{gap:16px;padding:16px;justify-content:space-between}.subject-practice-summary .btn{width:100%}.subject-practice-summary strong{font-size:22px}.subject-practice-summary span{font-size:9px;max-width:65px}.inline-experiment{padding:13px}.bank-layout{grid-template-columns:1fr}.inline-experiment svg text{font-size:13px}.bank-work{padding:20px}.bank-prompt{font-size:16px}}