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:root[data-theme=dark]{--bg:#151515;--surface:#1d1d1d;--surface-alt:#272727;--ink:#f2f2f2;--muted:#b0b0b0;--line:#363636;--blue:#e5e5e5;--blue-hover:#fff;--blue-soft:#2b2b2b;--green:#9cc8af;--green-soft:#26332b;--amber:#d8be8d;--amber-soft:#373126;--violet:#cecece;--violet-soft:#2b2b2b;--shadow:0 18px 64px #0005;color-scheme:dark}
*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;background:var(--bg);color:var(--ink);font:15px/1.5 Onest,system-ui,sans-serif;-webkit-font-smoothing:antialiased}button,input,select,textarea{font:inherit}button,a,input,select,[contenteditable=true]{-webkit-tap-highlight-color:transparent}button{cursor:pointer;color:inherit;touch-action:manipulation}button:disabled{cursor:default;opacity:.46}button,a{transition:background-color .16s,color .16s,border-color .16s,box-shadow .16s}a{color:var(--blue);text-decoration:none}button:focus-visible,a:focus-visible,input:focus-visible,select:focus-visible,[contenteditable]:focus-visible{outline:3px solid var(--blue);outline-offset:4px}h1,h2,h3,p{margin:0}h1,h2,h3{text-wrap:balance}h1{font-weight:570;letter-spacing:-1.2px;font-size:34px;line-height:1.2}h2{font-weight:560;font-size:22px;letter-spacing:-.5px}h3{font-weight:560;font-size:17px;letter-spacing:-.25px}svg{flex-shrink:0;vertical-align:middle}sub{font-size:.64em;line-height:0;vertical-align:-.28em}sup{font-size:.62em;line-height:0}.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}.skip-link{position:fixed;top:-100px;left:20px;background:var(--surface);padding:12px;z-index:100}.skip-link:focus{top:12px}.shell{min-height:100dvh;display:grid;grid-template-columns:var(--sidebar) minmax(0,1fr)}
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dialog{border:1px solid var(--line);border-radius:23px;padding:0;background:var(--surface);color:var(--ink);width:min(510px,calc(100% - 32px));max-height:calc(100dvh - 40px);box-shadow:var(--shadow);overscroll-behavior:contain}dialog::backdrop{background:#13213b48;backdrop-filter:blur(4px)}.dialog-body{padding:32px}.dialog-close{position:absolute;top:15px;right:15px}.dialog-symbol{margin-bottom:24px}.dialog-title{font-size:27px;letter-spacing:-.8px;line-height:1.25;font-weight:570;margin-bottom:10px;padding-right:22px}.dialog-description{font-size:14px;color:var(--muted);line-height:1.7}.detail-meta{display:flex;gap:9px;flex-wrap:wrap;margin:18px 0 28px}.pill{display:inline-flex;align-items:center;background:var(--surface-alt);padding:5px 10px;border-radius:7px;color:var(--muted);font-size:11px}.field-group{border:0;margin:0 0 24px;padding:0}.field-group legend,.field-label{font-size:13px;font-weight:550;margin-bottom:10px;display:block}.segmented{display:flex;padding:4px;border-radius:11px;background:var(--surface-alt);gap:3px}.segment{position:relative;flex:1;text-align:center;font-size:12px;cursor:pointer}.segment input{position:absolute;opacity:0;width:100%;height:100%;inset:0;margin:0;cursor:pointer}.segment span{padding:9px 8px;display:block;border-radius:8px;color:var(--muted)}.segment input:checked+span{background:var(--surface);box-shadow:0 1px 4px #0000000c;color:var(--ink)}.segment input:focus-visible+span{outline:2px solid var(--blue);outline-offset:1px}.select{width:100%;border:1px solid var(--line);background:var(--surface);color:var(--ink);border-radius:10px;padding:11px 12px;font-size:13px}.dialog-actions{display:flex;gap:10px;margin-top:26px}.dialog-actions .btn{flex:1}.dialog-footnote{font-size:11px;line-height:1.6;color:var(--muted);margin-top:14px}.dialog-footer{border-top:1px solid var(--line);padding:16px 32px;font-size:11px;color:var(--muted)}.about-prose p{font-size:14px;line-height:1.75;margin-top:15px;color:var(--muted)}.about-prose h3{margin-top:22px}.source-list{padding:0;list-style:none;margin:16px 0 0}.source-list li{padding:9px 0;font-size:12px;border-bottom:1px solid var(--line)}
.practice-topbar{height:82px;display:flex;align-items:center;justify-content:space-between;padding:0 36px;border-bottom:1px solid var(--line);gap:16px}.practice-title{text-align:center}.practice-title h1{font-size:17px;letter-spacing:-.3px}.practice-title p{color:var(--muted);font-size:11px;margin-top:3px}.back-button{display:flex;align-items:center;gap:7px;border:0;background:transparent;color:var(--muted);font-size:12px}.back-button:hover{color:var(--ink)}.practice-wrap{max-width:1080px;margin:0 auto;padding:25px 36px 24px;display:flex;flex-direction:column;min-height:calc(100dvh - 82px)}.progress-heading{display:flex;justify-content:space-between;color:var(--muted);font-size:12px;margin-bottom:10px}.progress-heading strong{font-weight:500;color:var(--ink)}.progress-track{height:4px;background:var(--line);border-radius:10px;overflow:hidden}.progress-fill{height:100%;background:var(--blue);border-radius:10px}.task-dots{display:flex;gap:5px;margin-top:14px;overflow:auto;padding:2px 2px 6px;scrollbar-width:thin}.task-dot{width:28px;height:28px;flex-shrink:0;display:grid;place-items:center;border:0;background:transparent;border-radius:8px;color:var(--muted);font-size:11px;font-variant-numeric:tabular-nums}.task-dot:hover{background:var(--surface-alt)}.task-dot.current{background:var(--blue-soft);color:var(--blue);box-shadow:inset 0 0 0 1px var(--blue)}.task-dot.solved{color:var(--green);background:var(--green-soft)}.task-dot.skipped{color:var(--amber);background:var(--amber-soft)}.exercise-heading{display:flex;align-items:center;justify-content:space-between;margin:25px 0 14px}.exercise-heading h2{font-size:18px}.exercise-mode{font-size:11px;color:var(--muted)}.equation-stage{border:1px solid var(--line);border-radius:20px;background:var(--surface);min-height:218px;display:flex;align-items:center;justify-content:center;padding:36px 25px;gap:16px;position:relative}.equation-side{display:flex;align-items:center;justify-content:center;flex-wrap:wrap;gap:7px 10px;font-size:clamp(26px,2.8vw,39px);font-weight:450;letter-spacing:-.6px;min-width:0;max-width:46%;line-height:1.6}.known-term{border:0;background:transparent;padding:3px 0;border-radius:5px;font-size:inherit;letter-spacing:inherit;font-weight:inherit;white-space:nowrap;position:relative}.known-term:hover{color:var(--blue)}.known-term.selected{box-shadow:0 2px 0 var(--blue);color:var(--blue)}.known-term .coefficient{color:var(--blue);margin-right:3px}.coefficient{font-variant-numeric:tabular-nums}.equation-plus{color:var(--muted);margin:0 3px;font-weight:350;white-space:pre}.reaction-arrow{display:flex;flex-direction:column;align-items:center;justify-content:center;align-self:center;position:relative;min-width:72px;max-width:175px;flex-shrink:0}.reaction-arrow .arrow-line{font-size:41px;font-weight:300;color:var(--muted);line-height:1.1}.reaction-conditions{position:absolute;bottom:calc(100% - 6px);left:50%;transform:translateX(-50%);width:max-content;max-width:195px;text-align:center;font-size:10px;line-height:1.45;color:var(--muted);font-weight:450;letter-spacing:0}.formula-editor{display:block;min-width:100px;max-width:100%;min-height:65px;line-height:1.6;outline:none;white-space:pre-wrap;overflow-wrap:anywhere;cursor:text;border-radius:7px;padding:2px 6px;caret-color:var(--blue);color:var(--blue);text-align:center;border-bottom:2px solid var(--blue);font-variant-ligatures:none;user-select:text}.formula-editor:empty:before{content:attr(data-placeholder);color:var(--muted);opacity:.65;font-size:24px;font-weight:400;letter-spacing:-.4px;pointer-events:none}.formula-editor:focus-visible{outline:0;background:var(--blue-soft);box-shadow:0 0 0 3px var(--blue-soft)}.formula-editor[contenteditable=false]{color:var(--green);border-color:var(--green)}.editor-side{flex:1;min-width:125px}.equation-hint{position:absolute;bottom:13px;left:18px;right:18px;text-align:center;color:var(--muted);font-size:10px}.feedback{display:flex;align-items:center;justify-content:center;gap:7px;min-height:42px;font-size:13px;color:var(--muted);padding:8px;text-align:center}.feedback.correct{color:var(--green)}.feedback.wrong,.feedback.invalid{color:var(--amber)}.keyboard{width:100%;max-width:790px;margin:0 auto}.keyboard-top{display:flex;align-items:center;justify-content:space-between;margin-bottom:12px;gap:12px}.keyboard-caption{font-size:11px;color:var(--muted)}.editor-tools{display:flex;gap:3px}.key-row{display:flex;justify-content:center;gap:7px;flex-wrap:wrap;margin-bottom:8px}.key{background:var(--surface);border:1px solid var(--line);border-bottom-width:2px;border-radius:10px;min-width:43px;height:42px;padding:0 13px;font-size:17px;display:inline-flex;align-items:center;justify-content:center;user-select:none}.key:hover{border-color:#aabfe8;background:var(--blue-soft)}.key:active{border-bottom-width:1px;transform:translateY(1px)}.element-key{width:61px;height:59px;font-size:25px;font-weight:460;position:relative;padding-top:8px}.element-key small{position:absolute;font-size:8px;left:8px;top:5px;color:var(--muted);font-weight:400}.fragment-key{font-size:19px;min-width:62px;height:47px}.key.operator{color:var(--blue);background:var(--blue-soft);border-color:transparent;border-bottom-color:var(--line)}.keyboard-tab{border:0;background:transparent;color:var(--muted);padding:5px 9px;border-radius:7px;font-size:12px}.keyboard-tab.active{background:var(--surface-alt);color:var(--ink)}.keyboard-spacer{width:5px}.practice-actions{display:flex;justify-content:space-between;align-items:center;gap:18px;margin-top:auto;padding:23px 0 0}.practice-actions .btn.primary{min-width:190px}.practice-actions .action-left{display:flex;align-items:center;gap:10px}.practice-actions small{color:var(--muted);font-size:11px}.exercise-note{text-align:center;color:var(--muted);font-size:10px;margin-top:15px}.queue-panel{display:flex;flex-direction:column;align-items:center;justify-content:center;padding:65px 20px;flex:1;text-align:center}.queue-icon{width:70px;height:70px;display:grid;place-items:center;background:var(--blue-soft);color:var(--blue);border-radius:22px;margin-bottom:26px}.queue-panel p{color:var(--muted);font-size:14px;max-width:400px;margin:13px 0 25px}.queue-actions{display:flex;gap:10px;justify-content:center;flex-wrap:wrap}
.results-wrap{max-width:790px;margin:0 auto;padding:46px 35px 60px}.results-mark{width:67px;height:67px;background:var(--green-soft);color:var(--green);border-radius:21px;display:grid;place-items:center;margin-bottom:25px}.results-wrap h1{font-size:33px}.results-subtitle{color:var(--muted);font-size:14px;margin-top:10px}.result-summary{display:flex;align-items:baseline;gap:15px;margin:36px 0 27px}.result-number{font-size:65px;font-weight:500;line-height:1;letter-spacing:-3px;color:var(--blue);font-variant-numeric:tabular-nums}.result-summary p{font-size:14px;color:var(--muted)}.result-summary strong{font-size:18px;font-weight:500;color:var(--ink);display:block;margin-bottom:4px}.result-metrics{border-top:1px solid var(--line);border-bottom:1px solid var(--line);padding:24px 0;display:grid;grid-template-columns:repeat(3,1fr);gap:18px;margin-bottom:27px}.metric strong{font-size:25px;font-weight:500;font-variant-numeric:tabular-nums;display:block;line-height:1.2;margin-bottom:7px}.metric span{color:var(--muted);font-size:12px}.result-actions{display:flex;gap:10px;flex-wrap:wrap;margin-bottom:38px}.review-list{display:grid;gap:8px}.review-item{background:var(--surface);border:1px solid var(--line);border-radius:12px;padding:15px 17px;display:flex;gap:12px;align-items:center}.review-index{color:var(--muted);font-size:11px;min-width:18px}.review-equation{font-size:17px;line-height:1.6;flex:1;min-width:0;overflow-wrap:anywhere}.review-state{font-size:11px;color:var(--muted);white-space:nowrap}.review-state.ok{color:var(--green)}.review-state.skip{color:var(--amber)}.review-placeholder{color:var(--muted)}.review-disclosure{display:flex;justify-content:space-between;align-items:center;margin-bottom:15px}.review-disclosure .text-link{font-size:12px}.section-description{font-size:13px;color:var(--muted);margin-top:8px}.practice-labs{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:20px;margin-top:30px}.lab-card{border:1px solid var(--line);border-radius:19px;background:var(--surface);padding:29px}.lab-card h2{margin-top:23px}.lab-card p{font-size:13px;color:var(--muted);line-height:1.7;margin:12px 0 24px}.lab-visual{height:100px;display:flex;align-items:center;justify-content:center;font-size:28px;letter-spacing:-.4px;color:var(--blue);border-radius:12px;background:var(--blue-soft)}.lab-card:nth-child(2) .lab-visual{background:var(--violet-soft);color:var(--violet)}.lab-visual small{font-size:14px;margin:0 10px}.lab-tag{font-size:11px;background:var(--surface-alt);color:var(--muted);border-radius:6px;padding:4px 8px;display:inline-block;margin-bottom:15px}.redox-workspace{margin-top:27px}.redox-equation{background:var(--surface);border:1px solid var(--line);border-radius:18px;padding:28px;text-align:center;font-size:25px;margin:22px 0 25px;line-height:1.9}.redox-row{display:grid;grid-template-columns:1fr 90px 24px 90px 1fr;align-items:center;gap:12px;padding:18px 0;border-bottom:1px solid var(--line)}.redox-row label{font-size:12px;color:var(--muted);display:block}.number-input{width:100%;border:1px solid var(--line);background:var(--surface);border-radius:10px;padding:9px;color:var(--ink);text-align:center}.redox-row strong{font-size:23px;font-weight:500}.redox-electrons{display:flex;align-items:center;gap:7px;justify-self:end}.redox-electrons input{width:65px}.redox-labels{display:grid;grid-template-columns:1fr 90px 24px 90px 1fr;gap:12px;font-size:11px;color:var(--muted)}.redox-labels span:last-child{text-align:right}.redox-multiplier{display:flex;align-items:center;gap:15px;margin-top:24px;flex-wrap:wrap}.redox-multiplier label{font-size:13px}.redox-multiplier input{width:70px}.redox-actions{display:flex;justify-content:space-between;margin-top:30px;gap:15px}.storage-warning{position:fixed;bottom:20px;left:50%;transform:translateX(-50%);max-width:calc(100% - 32px);padding:12px 18px;border:1px solid var(--line);background:var(--surface);box-shadow:var(--shadow);border-radius:12px;font-size:12px;z-index:80}.loading{min-height:100dvh;display:grid;place-content:center;text-align:center;color:var(--muted);gap:14px}.loading-mark{font-size:40px;color:var(--blue)}
@media(min-width:1600px){.content{padding-top:52px}.topic-card{min-height:170px;padding:27px}.topic-grid{gap:17px}.practice-wrap{padding-top:32px}.equation-stage{min-height:250px}.exercise-heading{margin-top:35px}}
@media(max-width:1200px){:root{--sidebar:210px}.sidebar{padding-left:13px;padding-right:13px}.topbar{padding:0 32px}.content{padding:34px 32px 45px}.page-heading{display:block}.search-wrap{max-width:100%;margin-top:23px}.topic-card{padding:19px;gap:13px}.topic-symbol{width:46px;height:54px;font-size:21px;padding-left:10px}.topic-copy h3{font-size:16px}.practice-topbar{padding:0 25px}.practice-wrap{padding-left:25px;padding-right:25px}.equation-side{font-size:29px}.reaction-arrow{min-width:55px}.reaction-conditions{max-width:140px}.practice-actions small{display:none}}
@media(max-width:940px){:root{--sidebar:185px}.brand{font-size:21px;padding-left:10px;gap:8px}.brand img{width:31px;height:31px}.nav-link{font-size:13px;padding-left:10px;gap:8px}.grade-link{padding-left:10px;font-size:13px}.local-note{font-size:10px;padding-left:10px;gap:5px}.content{padding:30px 25px 40px}.topbar{padding:0 25px}.topic-grid{grid-template-columns:1fr}.topic-card{min-height:130px}.topic-copy p{max-width:100%}.topic-meta{margin-top:11px}.practice-labs{grid-template-columns:1fr}.equation-stage{flex-wrap:wrap;padding:35px 18px 40px;gap:11px}.equation-side{max-width:100%;font-size:27px}.reaction-arrow{margin:0 6px}.formula-editor:empty:before{font-size:21px}.key{min-width:37px;padding:0 10px;height:39px}.element-key{width:53px;height:52px;font-size:23px}.keyboard-caption{display:none}.keyboard-top{margin-top:3px}.practice-wrap{padding-left:20px;padding-right:20px}.practice-title h1{max-width:240px}.exercise-mode{max-width:145px;text-align:right}.redox-row,.redox-labels{grid-template-columns:1fr 65px 15px 65px 1fr;gap:8px}.redox-electrons input{width:55px}}
@media(max-width:700px){.shell{display:block}.sidebar{position:static;height:auto;padding:17px 20px 0;border-right:0;border-bottom:1px solid var(--line);display:block}.brand{padding:0;font-size:22px}.brand img{width:32px;height:32px}.primary-nav{display:flex;margin-top:17px;gap:7px;overflow:auto}.nav-link{width:auto;white-space:nowrap;font-size:12px;padding:10px 11px;border-radius:9px 9px 0 0;gap:7px}.nav-link svg{width:16px;height:16px}.sidebar-divider,.grade-heading,.grade-nav,.sidebar-bottom{display:none}.mobile-theme{display:block;position:absolute;right:18px;top:16px}.topbar{height:52px;padding:0 21px}.topbar-note{font-size:10px}.breadcrumb{font-size:11px;gap:9px}.content{padding:26px 20px 40px}.page-heading{margin-bottom:22px}h1{font-size:28px;letter-spacing:-.9px}.page-description{font-size:13px;margin-top:9px}.search-wrap{margin-top:20px}.search{font-size:13px}.mobile-grades{display:flex;gap:7px;margin:0 0 19px;overflow:auto}.mobile-grades .tab{white-space:nowrap;background:var(--surface);border:1px solid var(--line);padding:8px 12px;font-size:12px}.mobile-grades .tab.active{color:var(--blue);background:var(--blue-soft);border-color:transparent;box-shadow:none}.catalog-tools{gap:8px;align-items:flex-start;margin-bottom:17px}.filter-tabs{gap:3px}.filter-tabs .tab{padding:7px 9px;font-size:11px}.catalog-count{font-size:10px;padding-top:8px}.topic-grid{gap:10px}.topic-card{border-radius:14px;padding:20px 17px;gap:14px;min-height:136px}.topic-copy h3{font-size:16px}.topic-copy p{font-size:11px}.topic-meta{font-size:10px}.topic-arrow{right:15px;top:24px}.topic-symbol{width:48px;height:55px}.section-heading{margin-top:25px}.section-heading h2{font-size:16px}.section-heading span{font-size:11px}.catalog-footer{display:block;font-size:10px;line-height:1.8}.catalog-footer span{display:block}.continue-banner{padding:15px;gap:11px;flex-wrap:wrap;border-radius:13px;margin-bottom:23px}.continue-icon{width:35px;height:35px;border-radius:10px}.continue-text strong{font-size:12px}.continue-text p{font-size:10px}.continue-banner .btn{min-height:34px;padding:8px 12px;font-size:11px}.dialog-body{padding:27px 23px}.dialog-footer{padding:15px 23px}.dialog-title{font-size:25px}.practice-shell .sidebar{display:none}.practice-topbar{height:71px;padding:0 16px;gap:9px}.practice-title h1{font-size:14px;max-width:190px}.practice-title p{font-size:9px}.back-button{font-size:0;gap:0}.back-button svg{width:21px;height:21px}.practice-topbar .text-link{font-size:11px}.practice-wrap{padding:18px 15px 16px;min-height:calc(100dvh - 71px)}.progress-heading{font-size:11px}.task-dots{margin-top:11px;gap:4px}.task-dot{width:26px;height:26px;font-size:10px}.exercise-heading{margin:23px 0 13px;align-items:flex-start}.exercise-heading h2{font-size:16px}.exercise-mode{font-size:10px;max-width:125px;padding-top:2px}.equation-stage{min-height:210px;padding:44px 15px 35px;border-radius:16px;gap:10px;display:flex;flex-direction:column}.equation-side{font-size:29px;line-height:1.65;max-width:100%;gap:5px 7px}.reaction-arrow{min-width:74px;margin:4px 0 2px;min-height:23px}.reaction-arrow .arrow-line{font-size:32px;line-height:1}.reaction-conditions{position:static;transform:none;max-width:275px;width:auto;font-size:9px;order:-1;line-height:1.5;margin-bottom:2px}.editor-side{min-width:140px;flex:auto;width:100%}.formula-editor{min-height:51px;min-width:150px}.formula-editor:empty:before{font-size:22px}.equation-hint{font-size:9px;bottom:9px}.feedback{min-height:45px;font-size:11px;padding:9px 2px}.key-row{gap:5px;margin-bottom:7px}.key{height:39px;min-width:29px;padding:0 8px;border-radius:8px;font-size:16px}.element-key{width:49px;height:51px;font-size:23px;padding-top:8px}.element-key small{font-size:7px;top:4px;left:6px}.fragment-key{min-width:48px;font-size:17px;padding:0 10px}.keyboard-top{margin-bottom:8px;gap:2px}.keyboard-tab{font-size:11px;padding:5px 8px}.editor-tools{gap:0}.editor-tools .icon-btn{width:31px;height:32px}.editor-tools svg{width:15px;height:15px}.keyboard-spacer{width:0}.practice-actions{padding-top:18px;gap:10px;padding-bottom:env(safe-area-inset-bottom)}.practice-actions .btn.primary{min-width:155px}.practice-actions .btn{font-size:12px;min-height:43px;padding:11px 16px}.practice-actions .action-left{gap:0}.exercise-note{font-size:9px;margin-top:12px}.results-wrap{padding:31px 21px 45px}.results-wrap h1{font-size:28px}.results-subtitle{font-size:12px}.result-number{font-size:56px}.result-summary{margin:28px 0 24px}.result-summary strong{font-size:16px}.result-summary p{font-size:12px}.result-metrics{gap:14px;padding:20px 0}.metric strong{font-size:24px}.metric span{font-size:10px}.result-actions .btn{font-size:12px;padding:10px 15px}.review-equation{font-size:14px}.review-state{font-size:9px}.review-item{padding:13px 11px;gap:8px}.review-index{min-width:12px;font-size:10px}.review-disclosure h2{font-size:18px}.review-disclosure .text-link{font-size:10px}.practice-labs{gap:15px;margin-top:24px}.lab-card{padding:23px}.lab-card h2{font-size:20px}.redox-equation{font-size:19px;padding:22px 14px}.redox-row,.redox-labels{grid-template-columns:32px 53px 12px 53px 1fr;gap:7px}.redox-row strong{font-size:21px}.redox-row label{font-size:10px}.redox-labels{font-size:9px}.redox-electrons input{width:44px}.number-input{padding:8px 5px;font-size:13px}.redox-multiplier{gap:9px}.redox-multiplier label{font-size:11px}.redox-multiplier input{width:54px}.queue-panel{padding:45px 14px}.queue-panel h2{font-size:23px}.queue-panel p{font-size:13px}}
@media(min-width:701px){.mobile-theme{display:none}}
@media(max-width:370px){.content{padding-left:15px;padding-right:15px}.sidebar{padding-left:15px;padding-right:15px}.primary-nav{gap:2px}.nav-link{font-size:11px;padding:10px 8px}.nav-link svg{width:14px}.topic-card{padding-left:14px;padding-right:14px;gap:11px}.key{min-width:27px;padding:0 6px}.element-key{width:45px}.practice-actions .btn.primary{min-width:140px}.practice-title h1{max-width:165px}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*,*:before,*:after{transition:none!important;animation:none!important}}
@media(pointer:fine){html{overscroll-behavior:none}}
@media print{.sidebar,.topbar,.practice-topbar,.practice-actions,.result-actions,.review-disclosure .text-link{display:none}.shell{display:block}.results-wrap{max-width:none;padding:0}.review-item{break-inside:avoid}body{background:white;color:black}.review-state{color:black}}

/* Compact desktop practice stays within a typical laptop viewport. */
#exercise{display:flex;flex-direction:column;flex:1;min-width:0}.known-term:disabled{opacity:1;cursor:default;color:var(--ink)}.compact-equation .equation-side{font-size:25px}.formula-editor{overflow-x:auto;overflow-y:hidden;overflow-wrap:normal;word-break:normal}.formula-token{white-space:nowrap}.keyboard button:disabled{opacity:.55}
@media(min-width:701px) and (max-height:850px){.practice-wrap{padding-top:16px;padding-bottom:14px}.task-dots{margin-top:8px;padding-bottom:3px}.exercise-heading{margin:16px 0 10px}.equation-stage{min-height:166px;padding-top:30px;padding-bottom:29px}.feedback{min-height:34px}.keyboard-top{margin-bottom:7px}.key-row{margin-bottom:6px}.key{height:36px}.element-key{height:49px}.practice-actions{padding-top:15px}.exercise-note{margin-top:9px}.keyboard{margin-top:0}}
@media(max-width:700px){.compact-equation .equation-side{font-size:21px}}

.formula-token{display:inline-block;white-space:nowrap}
.equation-side{flex:1 1 0}@media(max-width:700px){.equation-side{flex:none;width:100%}}@media(max-width:370px){.task-dots{gap:2px}.task-dot{width:24px;height:28px}}