@charset "UTF-8";
.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}
.learn-grid>div,.lab-grid>div,.source-grid>article{min-width:0}.route{max-width:100%}.unit{flex-shrink:0}
td.symbol{max-width:180px;overflow-wrap:anywhere}.sidebar{overflow-y:auto}.route{max-height:690px;overflow-y:auto}
:root{--paper:#f7f5ef;--ink:#24332e;--muted:#657269;--line:#d9ded3;--green:#245b43;--lime:#ddebaf;--cream:#eeeedf;--white:#fffefa;--orange:#99502a;--serif:Georgia,'Times New Roman',serif;--sans:'Segoe UI',Arial,sans-serif}
*{box-sizing:border-box}body{margin:0;background:var(--paper);color:var(--ink);font:16px/1.6 var(--sans)}button,input,select{font:inherit}button,a,input,select{touch-action:manipulation}button{cursor:pointer}button:disabled{opacity:.4;cursor:default}a{color:var(--green)}button{color:inherit}button:focus-visible,a:focus-visible,input:focus-visible,select:focus-visible,summary:focus-visible{outline:3px solid #ad683d;outline-offset:4px}button:hover:not(:disabled){filter:brightness(.96)}.skip{position:fixed;top:-80px;left:20px;z-index:30;background:white;padding:12px}.skip:focus{top:10px}.sidebar{position:fixed;inset:0 auto 0 0;width:254px;padding:34px 24px;background:#e9ecdf;border-right:1px solid var(--line);display:flex;flex-direction:column}.brand{font-size:29px;font-weight:650;letter-spacing:-1.2px;display:flex;align-items:center;text-decoration:none;color:var(--ink)}.brand-mark{font:38px var(--serif);margin-right:10px}.brand-dot{color:var(--green)}.side-caption{font-size:10px;letter-spacing:1.9px;margin:23px 0 33px;color:var(--muted)}nav{display:grid;gap:9px}.nav-item{background:none;border:0;text-align:left;border-radius:5px;padding:13px 12px;font-size:14px;font-weight:600}.nav-item span{font-size:11px;color:var(--muted);margin-right:15px}.nav-item.active{background:var(--green);color:white}.nav-item.active span{color:#c9debf}.side-bottom{margin-top:auto;padding-top:35px}.small-label,.eyebrow{font-size:11px;letter-spacing:1.6px;font-weight:650}.side-bottom p{font:23px/1.4 var(--serif)}.progress-track{height:4px;background:#ccd2c3;margin:20px 0 9px}.progress-track div{height:100%;background:var(--green);transition:width .2s}.side-bottom>span:last-of-type{font-size:12px;color:var(--muted)}.text-button{border:0;background:none;color:var(--green);padding:8px 0;text-align:left;font-size:13px;display:block}.workspace{margin-left:254px}.topbar{height:80px;display:flex;justify-content:space-between;align-items:center;border-bottom:1px solid var(--line);padding:0 42px;font-size:12px;color:var(--muted)}main{max-width:1280px;margin:auto;padding:40px 42px 60px;min-height:82vh}h1{font:clamp(32px,3.3vw,48px)/1.12 var(--serif);letter-spacing:-1.2px;margin:12px 0 15px;font-weight:normal}h2{font:29px/1.22 var(--serif);margin:8px 0 14px;font-weight:normal}h3{font-size:17px;line-height:1.4}.intro{color:var(--muted);max-width:650px;margin:0}.eyebrow{color:var(--green)}.hero{display:flex;justify-content:space-between;gap:24px;align-items:start;margin-bottom:32px}.hero-note{width:194px;flex-shrink:0;padding:17px;border:1px solid var(--line);border-radius:3px;font-size:12px}.hero-note strong{font-size:20px;display:block;font-family:var(--serif)}.pill{display:inline-block;padding:4px 9px;border-radius:3px;background:var(--cream);font-size:11px;color:var(--muted);font-weight:600}.pill.board{background:#e2eddb;color:#355c31}.pill.tutor{background:#f3e7db;color:#835331}.learn-grid{display:grid;grid-template-columns:220px minmax(0,1fr);gap:24px}.route{border-top:1px solid var(--line)}.unit{width:100%;display:flex;align-items:center;gap:12px;text-align:left;padding:15px 4px;border:0;border-bottom:1px solid var(--line);background:none}.unit-num{font:20px var(--serif);color:var(--muted);width:28px;flex-shrink:0}.unit b{display:block;font-size:13px;font-weight:600}.unit small{display:block;font-size:11px;color:var(--muted)}.unit.selected{background:#e6ebd8;padding-left:10px;border-left:3px solid var(--green)}.unit.done .unit-num{color:var(--green)}.lesson{background:var(--white);border:1px solid var(--line);border-radius:6px;overflow:hidden;min-width:0}.lesson-head{padding:20px 26px;border-bottom:1px solid var(--line);display:flex;justify-content:space-between;gap:10px;align-items:center}.lesson-body{padding:28px;min-height:330px}.lesson-body>p{max-width:680px}.formula{font:clamp(23px,2.4vw,33px)/1.6 var(--serif);padding:19px 22px;background:#f0f2e6;border-left:3px solid var(--green);margin:22px 0;overflow-wrap:anywhere}.reason{border-top:1px solid var(--line);padding-top:16px;color:var(--muted);font-size:14px}.lesson-actions{display:flex;align-items:center;justify-content:space-between;gap:10px;border-top:1px solid var(--line);padding:18px 26px}.btn{border:1px solid var(--line);border-radius:4px;background:var(--white);padding:10px 17px;font-size:13px;font-weight:600}.btn.primary{background:var(--green);border-color:var(--green);color:white}.btn.soft{background:var(--lime);border-color:var(--lime)}.step-dots{display:flex;gap:5px}.step-dots i{display:block;width:18px;height:3px;background:var(--line)}.step-dots i.on{background:var(--green)}.under-lesson{display:flex;justify-content:space-between;align-items:center;gap:16px;margin-top:13px;font-size:12px;color:var(--muted)}.bridge{margin-top:26px;padding:21px 25px;background:var(--green);color:#fff;display:flex;align-items:center;justify-content:space-between;gap:20px;border-radius:5px}.bridge p{margin:2px 0;color:#dce6d5;font-size:13px}.bridge strong{font-size:15px}.bridge .btn{white-space:nowrap}.toolbar{display:flex;gap:12px;margin:26px 0 16px}.search-wrap{position:relative;flex:1}.search-wrap span{position:absolute;left:15px;top:10px;color:var(--muted)}input[type=search]{width:100%;padding:12px 15px 12px 42px;border:1px solid var(--line);background:var(--white);border-radius:4px}select{border:1px solid var(--line);background:var(--white);padding:11px;border-radius:4px;max-width:260px}.table-wrap{overflow-x:auto;border:1px solid var(--line);border-radius:5px;background:var(--white)}table{width:100%;border-collapse:collapse;font-size:13px;text-align:left}th{background:#eef0e5;color:var(--muted);font-size:10px;letter-spacing:1px;text-transform:uppercase;padding:15px 18px}td{padding:18px;border-top:1px solid var(--line);vertical-align:top}td.symbol{font:27px var(--serif);color:var(--green);min-width:80px}td strong{display:block;font-size:14px}td small{display:block;color:var(--muted);margin-top:3px}.term-example{font-family:var(--serif);font-size:17px;display:block;margin-bottom:5px}.count{font-size:12px;color:var(--muted);margin:10px 0}.empty{padding:45px;text-align:center;color:var(--muted)}.lab-tabs{display:flex;gap:8px;margin:24px 0}.lab-tabs .active{background:var(--green);color:white;border-color:var(--green)}.lab-grid{display:grid;grid-template-columns:minmax(0,1.2fr) minmax(220px,.8fr);gap:22px}.panel{background:var(--white);border:1px solid var(--line);border-radius:5px;padding:26px}.number-picker{display:flex;align-items:center;justify-content:center;gap:30px;margin:25px 0}.number-picker output{font:72px/1 var(--serif);min-width:110px;text-align:center}.number-picker button{width:40px;height:40px;padding:0;font-size:22px}input[type=range]{width:100%;accent-color:var(--green)}.pair-grid{display:flex;flex-wrap:wrap;gap:9px;margin:20px 0}.pair{background:var(--cream);padding:8px 14px;border-radius:4px;font-family:var(--serif);font-size:22px}.pair.special{background:var(--lime);border:1px solid #b8cd85}.result{font:29px var(--serif);margin:18px 0 12px}.answer{background:#e8efdd;padding:15px;border-radius:4px;font-size:14px;margin-top:14px}.quiet{font-size:13px;color:var(--muted)}.formula-parts{display:flex;flex-wrap:wrap;gap:8px;margin:22px 0}.formula-parts button{font:23px var(--serif);padding:12px;background:var(--cream);border:1px solid var(--line);border-radius:4px}.formula-parts button.active{background:var(--green);color:white}.quote{font-family:var(--serif);font-size:23px;line-height:1.5}.source-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:20px;margin-top:25px}.source-card{background:var(--white);border:1px solid var(--line);border-radius:5px;overflow:hidden}.source-card img{width:100%;height:185px;object-fit:cover;object-position:center 52%;display:block}.source-card .source-text{padding:22px}.source-card h3{margin:8px 0}.source-card p{font-size:13px;color:var(--muted)}details{border-top:1px solid var(--line);margin-top:14px;padding-top:13px}summary{cursor:pointer;font-size:13px;color:var(--green);font-weight:600}.source-card details p{color:var(--ink)}footer{display:flex;flex-wrap:wrap;gap:10px;justify-content:space-between;padding:20px 42px;border-top:1px solid var(--line);font-size:10px;color:var(--muted)}.question-box{margin-top:20px}.question-box button{margin:5px 7px 5px 0}.checked-badge{font-size:11px;color:var(--green)}
@media(min-width:1500px){main{padding-top:55px}.lesson-body{min-height:360px}}
@media(max-width:1050px){.sidebar{width:205px;padding:25px 17px}.workspace{margin-left:205px}main{padding:30px 25px}.topbar{padding:0 25px}.learn-grid{grid-template-columns:180px minmax(0,1fr);gap:15px}.hero-note{display:none}.lesson-body{padding:22px}.nav-item{padding:12px 7px}.nav-item span{margin-right:7px}}
@media(max-width:900px){.sidebar{position:static;width:100%;padding:16px 20px;border-right:0;border-bottom:1px solid var(--line)}.brand{font-size:25px}.side-caption,.side-bottom{display:none}nav{display:flex;overflow:auto;margin-top:12px;gap:5px}.nav-item{white-space:nowrap;font-size:12px;padding:10px}.nav-item span{display:none}.workspace{margin-left:0}.topbar{height:48px;padding:0 20px;font-size:10px}.date{font-size:9px}main{padding:27px 20px 40px}.hero{margin-bottom:24px}h1{font-size:35px}.learn-grid,.lab-grid,.source-grid{grid-template-columns:1fr}.route{display:flex;overflow:auto;border:0;gap:6px;padding-bottom:8px}.unit{min-width:160px;border:1px solid var(--line);padding:9px}.unit.selected{padding-left:9px}.unit small{font-size:10px}.unit-num{font-size:17px;width:20px}.lesson-head,.lesson-actions{padding:15px 18px}.lesson-body{padding:20px;min-height:300px}.under-lesson{align-items:start}.bridge{padding:18px;align-items:start;flex-direction:column}.toolbar{flex-direction:column}.toolbar select{max-width:100%}td,th{padding:13px 12px}td{min-width:170px}td.symbol{min-width:75px}.table-wrap{margin-right:-3px}footer{padding:15px 20px}.lab-tabs{flex-wrap:wrap}.formula{font-size:25px}.source-card img{height:210px}}
@media(max-width:900px){.unit{width:180px;min-width:180px;flex:0 0 180px}}
@media(prefers-reduced-motion:reduce){*{transition:none!important;scroll-behavior:auto!important}}

/* Book companion v2: clear source/status hierarchy and bilingual reading. */
.btn{color:var(--ink);text-decoration:none;display:inline-block;line-height:1.5;text-align:center}
.bridge .btn{color:var(--green);background:var(--white)}
.language-switch{min-width:44px;min-height:40px;padding:8px 12px;background:var(--white);color:var(--green);border-color:var(--green);text-transform:lowercase}
.nav-item{display:block;color:inherit;text-decoration:none}.topbar{gap:16px}.nav-item{line-height:1.35}.sidebar nav{gap:5px}
.book-route .unit-num{font-size:16px;width:35px}.book-route .unit{padding:16px 7px}.book-route .unit.selected{border-left:3px solid var(--green)}
.lesson-body p{font-size:17px;line-height:1.75}.lesson-body .reason{font-size:14px}.formula{white-space:pre-line}
.lesson-head .pill{max-width:85%}.lesson-head>.quiet{white-space:nowrap}
.lesson-actions{flex-wrap:wrap}.lesson-actions .btn{max-width:100%}
label{display:block;font-size:13px;font-weight:600;margin:18px 0 6px}
textarea{display:block;width:100%;max-width:100%;padding:12px;color:var(--ink);background:var(--paper);border:1px solid var(--line);border-radius:4px;font:16px/1.6 var(--sans);resize:vertical}
textarea:focus-visible,input:not([type=checkbox]):not([type=radio]):focus-visible{outline:2px solid #ad683d;outline-offset:2px}
.action-row{display:flex;flex-wrap:wrap;align-items:center;gap:10px;margin:18px 0}.action-row .btn{overflow-wrap:anywhere}
.section-finish{margin-top:24px}.related{margin:24px 0 12px;padding-top:15px;border-top:1px solid var(--line)}
.coverage-strip{display:flex;flex-wrap:wrap;gap:14px 28px;padding:17px 20px;background:#e6ebd8;border:1px solid var(--line);margin-bottom:20px;font-size:13px}
.coverage-strip b{font:24px var(--serif);margin-right:4px}
.book-note p:first-child{margin-top:0}.book-note p:last-child{margin-bottom:0}
.chapter{background:var(--white);border:1px solid var(--line);border-radius:5px;padding:0;margin:15px 0}
.chapter>summary{display:flex;align-items:center;gap:20px;padding:22px;font:22px/1.35 var(--serif);color:var(--ink);list-style:none}
.chapter>summary:after{content:'+';margin-left:auto;font:25px var(--sans)}.chapter[open]>summary:after{content:'−'}
.chapter-number{font:24px var(--serif);color:var(--green);min-width:30px}.chapter summary small{display:block;font:12px var(--sans);color:var(--muted);margin-top:5px}
.chapter-row{display:flex;align-items:center;justify-content:space-between;gap:20px;padding:20px 24px;border-top:1px solid var(--line)}
.chapter-row>div:first-child{flex:1;min-width:0}.chapter-row .action-row{max-width:260px;justify-content:flex-end}.chapter-row h3{margin:0;font-size:15px}.chapter-row p{margin:5px 0}
.appendices{margin-top:25px}.assignment-heading{display:flex;justify-content:space-between;gap:15px;align-items:center}
.assignment-list{margin-top:24px}.exercise{background:var(--white);border:1px solid var(--line);border-radius:4px;padding:18px 22px;margin:10px 0}
.exercise>summary{display:flex;align-items:center;gap:18px;font-weight:400;font-size:14px}.exercise summary strong{min-width:66px;font-size:16px;color:var(--green)}.exercise summary span{flex:1}.exercise summary small{white-space:nowrap;color:var(--muted)}
.exercise>summary:after{content:'+';font-size:20px}.exercise[open]>summary:after{content:'−'}
.book-route{position:sticky;top:22px}.book-route .quiet{font-size:12px}.table-wrap code{overflow-wrap:anywhere}.toolbar>input{flex:1;min-width:0}
@media(max-width:1050px){.sidebar{width:220px}.workspace{margin-left:220px}.learn-grid{grid-template-columns:170px minmax(0,1fr)}.side-bottom p{font-size:20px}}
@media(max-width:900px){.sidebar{width:100%}.workspace{margin-left:0}.learn-grid{grid-template-columns:1fr}.book-route{position:static;display:flex;flex-wrap:wrap;gap:6px}.book-route>p{width:100%;margin:0 0 8px}.book-route>.unit{flex:1 1 145px;width:auto;min-width:0}.book-route>.btn{width:100%}.chapter-row{flex-direction:column;align-items:stretch;gap:6px}.chapter-row .action-row{max-width:none;justify-content:start;margin:10px 0 0}.chapter>summary{font-size:19px;padding:16px;gap:12px}.coverage-strip{gap:10px}.lesson-body p{font-size:16px}.under-lesson{flex-wrap:wrap}.exercise{padding:15px}.exercise>summary{gap:10px}.source-card img{height:220px}.topbar{padding:0 20px;height:62px}.language-switch{min-width:44px;padding:8px 10px}}
@media(max-width:480px){main{padding:24px 16px}h1{font-size:31px}.topbar>span{max-width:170px}.lesson-head{align-items:start}.lesson-actions{padding:14px}.lesson-actions>.quiet{display:none}.chapter-row{padding:16px}.exercise summary strong{min-width:55px}.exercise summary small{display:none}.panel{padding:20px}.source-grid{gap:16px}}


/* Website-first learning paths; protected source links stay secondary. */
.learning-choices{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:12px;margin:0 0 28px}.path-card{display:flex;min-height:145px;flex-direction:column;padding:20px;border:1px solid var(--line);border-radius:5px;background:var(--white);color:var(--ink);text-decoration:none}.path-card>span{font-size:11px;color:var(--muted)}.path-card strong{font:23px/1.25 var(--serif);margin:auto 0 8px}.path-card small{color:var(--muted)}.path-card:hover{border-color:var(--green);background:#f4f6eb}.lesson-context{margin:0 0 22px;padding-bottom:22px;border-bottom:1px solid var(--line)}.lesson-context h1{margin-bottom:8px}.lesson-context .action-row{margin-top:18px}.source-access{margin-top:14px}.source-access>summary{color:var(--muted)}.chapter-row>div:last-child{min-width:min(100%,360px)}.chapter-row .action-row{max-width:520px}
@media(max-width:900px){.learning-choices{grid-template-columns:repeat(2,minmax(0,1fr))}.path-card{min-height:125px}.chapter-row>div:last-child{min-width:0}}
@media(max-width:480px){.learning-choices{grid-template-columns:1fr}.path-card{min-height:105px}.path-card strong{margin:14px 0 5px}}
.continue-panel{display:grid;grid-template-columns:minmax(0,1fr) auto;align-items:center;gap:18px;margin:0 0 20px}.continue-copy{display:grid;min-width:0;gap:5px}.continue-topic{font:23px/1.3 var(--serif);overflow-wrap:anywhere}.continue-copy .quiet{display:block}.continue-action{white-space:nowrap;text-decoration:none}.sidebar-scroll-content{display:flex;min-height:100%;flex-direction:column}.sidebar-ruler-shell{display:none;position:fixed;top:0;left:0;width:20px;height:0;z-index:61;pointer-events:none}.sidebar-ruler-shell>.sidebar-ruler-rail{pointer-events:auto}.sidebar-with-ruler{outline-offset:-4px}
@media(min-width:901px){.sidebar-with-ruler[data-ruler-active="true"]{-ms-overflow-style:none;scrollbar-width:none}.sidebar-with-ruler[data-ruler-active="true"]::-webkit-scrollbar{display:none;width:0;height:0}.sidebar-ruler-shell[data-ruler-active="true"]{display:block}}
@media(max-width:600px){.continue-panel{grid-template-columns:1fr;align-items:start;gap:12px}.continue-action{justify-self:start}}
#export-help{display:block;font-size:11px;line-height:1.5;margin-top:6px}.side-bottom #export{margin-top:12px}

/* Trainer and introductory guides reuse the book companion's paper-and-ink system. */
.trainer-page,.guide-page{min-height:100vh}.trainer-topbar{height:auto;min-height:72px;background:var(--paper);position:sticky;top:0;z-index:10}.brand.compact{font-size:23px}.brand.compact .brand-mark{font-size:30px}.trainer-shell,.guide-shell{max-width:980px}.trainer-hero{margin-top:12px}.trainer-modes,.trainer-pagination,.guide-navigation{display:flex;flex-wrap:wrap;align-items:center;gap:10px;margin:20px 0}.trainer-pagination{justify-content:space-between}.trainer-topic{max-width:360px}.trainer-topic select{display:block;width:100%;max-width:none;margin-top:6px}.trainer-card{margin-top:18px}.trainer-card h2{font-size:clamp(22px,3vw,30px);line-height:1.35}.trainer-card input[type=text],.trainer-card textarea{width:100%;border:1px solid var(--line);background:var(--paper);border-radius:4px;padding:12px;color:var(--ink);font:16px/1.5 var(--sans)}.trainer-card fieldset{border:0;padding:0;margin:22px 0}.trainer-card legend{font-weight:650;margin-bottom:10px}.choice-row{display:flex;gap:10px;align-items:flex-start;padding:10px 12px;border:1px solid var(--line);border-radius:4px;margin:8px 0;background:var(--paper)}.choice-row input{margin-top:5px;accent-color:var(--green)}.trainer-truth{max-width:560px;margin:20px 0;border:1px solid var(--line)}.trainer-truth td,.trainer-truth th{text-align:center;min-width:72px}.boolean-field{display:flex;flex-wrap:wrap;gap:16px;padding:14px!important;border-top:1px solid var(--line)!important}.boolean-field label{margin:0}.proof-cards{padding:0;list-style:none;display:grid;gap:9px}.proof-cards li{display:flex;justify-content:space-between;gap:14px;align-items:center;padding:13px;border:1px solid var(--line);background:var(--paper);border-radius:4px}.proof-cards button{min-width:42px;min-height:42px;border:1px solid var(--line);background:var(--white);margin-left:5px;border-radius:4px}.trainer-help{margin-top:14px}.answer.incorrect{background:#f5e6de;border-left:3px solid var(--orange)}.answer.incomplete{background:#f3eedf}.walkthrough{margin-top:20px;padding-top:14px;border-top:1px solid var(--line)}.hint{padding:12px 15px;background:#f3eedf;border-left:3px solid #a77b42}.source-line{margin-top:24px}.math-keyboard{position:sticky;bottom:0;margin:18px 0;padding:12px;border:1px solid var(--line);background:rgba(255,254,250,.97);box-shadow:0 -5px 20px rgba(36,51,46,.08);z-index:8}.math-keyboard-target{font-size:12px;color:var(--muted);margin:0 0 8px}.math-keyboard-keys{display:flex;flex-wrap:wrap;gap:6px}.math-keyboard-keys button{min-width:42px;min-height:42px;background:var(--paper);border:1px solid var(--line);border-radius:4px;font:21px var(--serif)}.exam-status{display:flex;flex-wrap:wrap;align-items:center;gap:12px;margin:18px 0}.exam-status strong{margin-right:auto}.topic-checks{display:grid;grid-template-columns:repeat(6,minmax(80px,1fr));gap:6px;margin:18px 0}.topic-checks label{display:flex;gap:7px;align-items:center;margin:0;padding:8px;border:1px solid var(--line);border-radius:4px}.trainer-local-note{text-align:center;margin:25px 0}.guide-unit{background:var(--white);border:1px solid var(--line);border-radius:6px;padding:clamp(20px,4vw,44px)}.guide-unit>header{margin-bottom:30px}.coverage-note{padding:12px 15px;background:var(--cream);border-left:3px solid var(--green)}.guide-unit>section,.guide-unit>aside,.guide-unit>details{margin-top:28px}.guide-steps{padding-left:24px}.guide-steps>li{padding:8px 0 18px}.guide-steps h3{font:23px/1.3 var(--serif);margin-bottom:8px}.guide-unit .formula{font-size:clamp(19px,2.4vw,28px);white-space:pre-wrap}.symbol-list{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:8px}.symbol-list div{display:grid;grid-template-columns:55px 1fr;padding:10px;border-bottom:1px solid var(--line)}.symbol-list dt{font:24px var(--serif);color:var(--green)}.worked-example,.pitfall{padding:20px;background:var(--cream);border-radius:4px}.pitfall{background:#f5e9df}.guide-navigation{justify-content:space-between}.self-check details{margin-left:18px}
@media(max-width:700px){.trainer-topbar{padding:10px 14px;align-items:flex-start}.trainer-topbar .account-actions{flex-wrap:wrap;justify-content:flex-end}.trainer-topbar .brand{margin-top:4px}.trainer-shell,.guide-shell{padding:24px 15px 45px}.trainer-modes .btn{flex:1 1 145px}.topic-checks{grid-template-columns:repeat(3,minmax(70px,1fr))}.symbol-list{grid-template-columns:1fr}.proof-cards li{align-items:flex-start}.math-keyboard{margin-left:-5px;margin-right:-5px}.guide-unit{padding:20px}.guide-navigation .btn{max-width:48%}}
@media(max-width:420px){.trainer-topbar .brand{font-size:0}.trainer-topbar .brand-mark{font-size:28px}.trainer-topbar .account-actions .btn{padding:8px 9px}.topic-checks{grid-template-columns:repeat(2,minmax(70px,1fr))}.trainer-pagination span{order:-1;width:100%;text-align:center}.proof-cards li{display:block}.proof-cards li>span:last-child{display:block;margin-top:10px}}

/* Sequential guide navigation and exact catalog return links. */
.trainer-topic-row{display:flex;flex-wrap:wrap;align-items:end;gap:12px}.trainer-topic-row .trainer-topic{width:min(100%,420px);max-width:none}.guide-step-map{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:8px;margin:18px 0}.guide-step-map button{display:flex;align-items:center;gap:10px;min-height:48px;padding:9px 12px;border:1px solid var(--line);border-radius:4px;background:var(--paper);color:var(--ink);text-align:left}.guide-step-map button span{display:grid;place-items:center;flex:0 0 28px;height:28px;border-radius:50%;background:var(--cream);font-weight:700}.guide-step-map button.active{border-color:var(--green);background:#f4f6eb}.guide-current-step{padding:clamp(18px,3vw,30px);border:1px solid var(--line);border-radius:5px;background:var(--white)}.guide-current-step h3{font:clamp(23px,3vw,31px)/1.3 var(--serif);margin:6px 0 12px}.guide-step-navigation{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:10px;margin-top:14px}.guide-step-navigation .btn{white-space:normal;min-height:48px}
@media(max-width:700px){.guide-step-map,.guide-step-navigation{grid-template-columns:1fr}}

/* Keep all owner controls and the shared language switch inside a narrow viewport. */
@media(max-width:480px){.workspace>.topbar{height:auto;min-height:96px;padding:10px 16px;flex-wrap:wrap;align-content:center;row-gap:8px}.workspace>.topbar>span:first-child{width:100%;max-width:none}.workspace>.topbar>.account-actions{display:flex;width:100%;max-width:none;flex-wrap:wrap;justify-content:flex-start;gap:6px}.workspace>.topbar>.account-actions .btn{min-width:0;padding:8px 10px}.workspace>.topbar>.account-actions .language-switch{min-width:44px}}

/* Optional field-local symbol panel never obscures the exercise. */
.math-keyboard{position:static;box-shadow:none;z-index:auto;padding:0;border:0;background:transparent;margin:10px 0 18px}.math-keyboard>div{padding:12px;margin-top:8px;border:1px solid var(--line);background:var(--paper)}.math-keyboard-toggle{min-height:44px}.answer,.hint,.self-review{overflow-wrap:anywhere;min-width:0}.self-review{margin:20px 0}.proof-cards li>span{min-width:0}.proof-cards li>span:last-child{flex-shrink:0}

.proof-cards li.dependency-highlight{border-color:var(--orange);box-shadow:inset 3px 0 var(--orange)}
/* Shared inline entry tools: no overlay on reading or card tasks. */
.math-keyboard{position:static;margin:10px 0 18px;max-width:100%;min-width:0}
.math-keyboard .math-keyboard-keys{padding:0;border:0;background:transparent;margin:6px 0;gap:5px}
.math-keyboard-label{font-size:12px;color:var(--muted);font-weight:600}
.math-keyboard-keys button{min-width:36px;min-height:44px;padding:4px 8px}
.math-keyboard-keys .math-keyboard-toggle{font:13px var(--sans)}
.topic-primary-actions{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:10px}
.topic-primary-actions .btn{text-align:center;display:flex;justify-content:center;align-items:center;min-width:0;height:100%}
.chapter-row{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1.3fr);align-items:start}.chapter-row>div:last-child{min-width:0}
.topic-actions{min-width:0}.topic-extra{margin:12px 0;font-size:14px}.introduction-entry{margin:-8px 0 28px}
.assignment-workspace{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:24px;margin:20px 0}
.assignment-reading,.assignment-attempt{min-width:0}.assignment-reading iframe{display:block;width:100%;height:620px;max-height:75vh;border:1px solid var(--line);background:var(--paper)}
.assignment-attempt textarea{width:100%;min-height:280px;resize:vertical;font:inherit}
.assignment-pane-tabs{display:none}.reader-access{padding:20px;border:1px solid var(--line);background:var(--paper)}
.assignment-topic-links{padding-top:12px;border-top:1px solid var(--line)}
.exercise>summary{display:grid;grid-template-columns:90px minmax(0,1fr) auto;gap:12px;align-items:start}
.glossary-list{display:grid;gap:16px}.glossary-entry{display:grid;grid-template-columns:minmax(180px,.9fr) minmax(140px,.7fr) minmax(0,1.2fr) minmax(0,1.3fr);gap:20px;padding:22px;border:1px solid var(--line);border-radius:4px;background:var(--white)}
.glossary-entry>div{min-width:0;word-break:normal;overflow-wrap:normal}.glossary-entry p{margin:0 0 10px}.glossary-entry h2{font:600 17px/1.4 var(--sans);margin:0 0 8px}.glossary-entry h3{font-size:12px;color:var(--muted);margin:0 0 8px}.glossary-symbol{overflow-x:auto}.glossary-symbol .symbol{white-space:nowrap;word-break:normal;overflow-wrap:normal;display:block;font:23px/1.5 var(--serif)}.glossary-entry code{white-space:pre-wrap;word-break:normal}.glossary-entry small{display:block}
@media(max-width:1300px){.glossary-entry{grid-template-columns:minmax(0,1fr) minmax(0,1.4fr)}.chapter-row{grid-template-columns:minmax(0,1fr)}.assignment-workspace{gap:16px}}
@media(max-width:700px){.assignment-workspace{display:block}.assignment-pane-tabs{display:flex;gap:10px;margin-bottom:16px}.assignment-pane-tabs .btn{flex:1}.assignment-workspace[data-pane="attempt"] .assignment-reading,.assignment-workspace[data-pane="reading"] .assignment-attempt{display:none}.assignment-reading iframe{height:65vh}.exercise>summary{grid-template-columns:minmax(0,1fr) auto}.exercise>summary span{grid-row:2;grid-column:1/-1}.glossary-entry{grid-template-columns:minmax(0,1fr);gap:14px;padding:18px}.glossary-symbol .symbol{font-size:23px}.topic-primary-actions{grid-template-columns:minmax(0,1fr)}.math-keyboard{margin-left:0;margin-right:0}}
@media(max-width:700px){.exercise>summary small{display:block;grid-row:1;grid-column:2;margin-right:22px}.exercise>summary::after{grid-row:1;grid-column:2;justify-self:end}.exercise>summary>strong{grid-row:1;grid-column:1}}
/* At enlarged text sizes, hyphenate only words too long for the full card. */
.glossary-entry>div{hyphens:auto;overflow-wrap:break-word}.glossary-symbol,.glossary-symbol .symbol{hyphens:none;overflow-wrap:normal}
.reasoning-links{border:1px solid var(--line);border-radius:4px;padding:18px;margin:22px 0}.reasoning-links h2{font-size:24px}.reasoning-links .quiet{max-width:850px;margin:8px 0}.reasoning-links .btn{font-size:13px}
.reasoning-page textarea{font:inherit;width:100%;resize:vertical;min-height:220px}.reasoning-page .panel{margin:26px 0}.reasoning-steps li{margin:14px 0}.reasoning-matrices{display:grid;grid-template-columns:repeat(auto-fit,minmax(min(100%,250px),1fr));gap:18px;margin:20px 0}.reasoning-matrices figure{min-width:0;margin:0}.reasoning-matrices figcaption{font-size:14px;line-height:1.5;margin-bottom:8px;overflow-wrap:break-word}.matrix-scroll{max-width:100%;overflow-x:auto;margin:18px 0}.matrix-scroll table{width:auto;min-width:100%;table-layout:auto;border-collapse:collapse}.matrix-scroll th,.matrix-scroll td{min-width:36px;text-align:center;padding:8px;border:1px solid var(--line);white-space:nowrap;word-break:normal;overflow-wrap:normal;font-size:16px}.reasoning-worked .matrix-scroll td{white-space:normal;min-width:90px}.reasoning-worked .reasoning-matrices td{white-space:nowrap;min-width:36px}.reasoning-page .formula{font-size:20px;overflow-wrap:break-word}.reasoning-page .action-row{gap:10px}.reasoning-page .action-row .btn{max-width:100%;white-space:normal}.reasoning-task,.reasoning-worked{min-width:0}.exam-status span{overflow-wrap:break-word;min-width:0}
@media(max-width:700px){.reasoning-page .panel{padding:18px}.reasoning-links{padding:15px}.reasoning-page .reasoning-steps{padding-left:22px}.reasoning-links .action-row{display:grid;grid-template-columns:minmax(0,1fr)}}
.matrix-scroll th{text-transform:none;letter-spacing:normal}
/* Reviewed topic glossary and local concept help share the existing reading surface. */
.glossary-group{margin:34px 0}.glossary-group>h2{font:28px/1.35 var(--serif);margin:0 0 18px}.glossary-entry{scroll-margin-top:120px}.glossary-entry.without-notation{grid-template-columns:minmax(160px,.9fr) minmax(0,1.2fr) minmax(0,1.3fr)}.glossary-links{grid-column:1/-1;border-top:1px solid var(--line);padding-top:12px;font-size:14px}.glossary-links p{line-height:1.8}.glossary-links details{margin-top:10px}.glossary-entry>div{hyphens:none;overflow-wrap:normal}.glossary-entry h2,.glossary-entry h3{word-break:normal;overflow-wrap:normal}.glossary-entry h3{font-size:14px}.glossary-symbol .symbol{width:100%;font-size:22px}.glossary-example p,.glossary-meaning p{white-space:pre-line}.glossary-example details{margin:12px 0}.glossary-links a{display:inline-block;max-width:100%;vertical-align:top}
.concept-support,.topic-vocabulary,.concept-disclosure{margin:14px 0;padding:14px 16px;border:1px solid var(--line);border-radius:4px;background:var(--paper);min-width:0}.concept-support>summary,.topic-vocabulary>summary,.concept-disclosure>summary{font-size:16px;line-height:1.5;font-weight:600;cursor:pointer;overflow-wrap:break-word}.concept-disclosure p{font-size:16px;line-height:1.7}.concept-disclosure>details{padding:12px 0}.prerequisite-help h2{font:24px/1.3 var(--serif)}.concept-links{display:flex;flex-wrap:wrap;gap:10px 18px;margin-top:16px;font-size:14px;line-height:1.6}.concept-links a{max-width:100%;overflow-wrap:break-word}.local-formula{font:19px/1.7 var(--serif);white-space:pre;word-break:normal;overflow-wrap:normal;overflow-x:auto;max-width:100%;padding:10px 4px;margin:12px 0;background:transparent;color:var(--ink)}.concept-support .local-formula{font-size:18px}.lesson-addition{margin:30px 0;border-top:1px solid var(--line);padding-top:24px;min-width:0;scroll-margin-top:110px}.lesson-addition>h2{font:27px/1.35 var(--serif)}.addition-worked,.lesson-addition .self-check{padding:16px;border:1px solid var(--line);margin:18px 0;background:var(--paper);overflow-wrap:normal}.argument-steps{padding-left:24px}.argument-steps>li{padding:10px 0;min-width:0}.argument-steps p{font-size:16px;line-height:1.75}.argument-why{border-left:2px solid var(--line);padding-left:14px}.reasoning-compact{display:flex;flex-wrap:wrap;gap:12px;margin:24px 0;font-size:16px}.study-return{margin:12px 0}.symbol-list>div{grid-template-columns:minmax(65px,.6fr) minmax(0,1.4fr)}.symbol-list dt{overflow-x:auto;white-space:nowrap}
@media(max-width:1300px){.glossary-entry.without-notation{grid-template-columns:minmax(0,1fr) minmax(0,1.4fr)}}
@media(max-width:700px){.glossary-entry.without-notation{grid-template-columns:minmax(0,1fr)}.concept-support,.topic-vocabulary,.concept-disclosure{padding:12px}.concept-support .concept-disclosure{padding:10px}.glossary-entry h2{font-size:18px}.glossary-entry p{overflow-wrap:break-word}.addition-worked,.lesson-addition .self-check{padding:12px}.lesson-addition>h2{font-size:24px}.local-formula{font-size:18px}.symbol-list>div{grid-template-columns:minmax(0,1fr);gap:6px}}
/* Local reasoning roles: labels and geometry carry meaning without colour. */
.colour-cue-control{display:inline-flex;align-items:center;gap:8px;min-height:44px;margin:14px 0 0;font-size:14px;cursor:pointer}.colour-cue-control input{width:18px;height:18px;accent-color:var(--green)}
.reasoning-page .role-state{--cue-ink:#46544e;--cue-paper:#f0f2ec}.reasoning-page .role-action{--cue-ink:#315a73;--cue-paper:#edf3f7}.reasoning-page .role-justification{--cue-ink:#765428;--cue-paper:#f7f0e4}.reasoning-page .role-result{--cue-ink:#255c48;--cue-paper:#edf4ef}
.reasoning-role{display:inline-block;color:var(--cue-ink);background:var(--cue-paper);padding:3px 8px;font:600 14px/1.4 var(--sans);border:1px solid var(--cue-ink);border-radius:2px;margin:0 6px 6px 0}.reasoning-role.role-result{border-bottom-style:double;border-bottom-width:3px}
.solution-step{margin:26px 0;padding:18px 0;border-top:1px solid var(--cue-ink);min-width:0}.solution-step.role-action{border:2px solid var(--cue-ink);padding:18px}.solution-step h4{font:600 22px/1.4 var(--serif);margin:4px 0 14px;text-transform:none;letter-spacing:normal}.solution-step p,.solution-conclusion p{color:var(--ink);font-size:16px;line-height:1.75;word-break:normal;overflow-wrap:break-word}
.solution-conclusion{padding:18px 0;border-bottom:4px double var(--cue-ink)}.solution-trace,.solution-matrix{margin:24px 0;min-width:0;max-width:100%}.solution-trace figcaption,.solution-matrix figcaption{font-size:16px;font-weight:600;margin:0 0 12px;overflow-wrap:break-word}.solution-trace table{width:100%;border-collapse:collapse;table-layout:fixed}.solution-trace td,.solution-trace th{border:1px solid var(--line);padding:10px;text-align:left;vertical-align:top;font-size:16px;word-break:normal;overflow-wrap:normal;text-transform:none;letter-spacing:normal}.solution-trace th{font-weight:600}.solution-trace td>span:last-child{display:block}.trace-mobile-label{display:none}.trace-focus{outline:2px solid #315a73;outline-offset:-2px}
.solution-matrix .matrix-scroll table{min-width:0}.solution-matrix .matrix-scroll th,.solution-matrix .matrix-scroll td{min-width:48px}.solution-matrix .matrix-focus{outline:2px solid #315a73;outline-offset:-3px;background:#edf3f7}.matrix-correspondence{font-size:14px!important}
.reasoning-page[data-colour-cues="off"] .reasoning-role,.reasoning-page[data-colour-cues="off"] .solution-step,.reasoning-page[data-colour-cues="off"] .solution-conclusion{--cue-ink:var(--ink);--cue-paper:transparent}.reasoning-page[data-colour-cues="off"] .matrix-focus{background:transparent;outline-color:currentColor}.reasoning-page[data-colour-cues="off"] .trace-focus{outline-color:currentColor}
@media(max-width:700px){.solution-step.role-action{padding:12px}.solution-trace table,.solution-trace tbody,.solution-trace tr,.solution-trace td{display:block;width:100%}.solution-trace thead{position:absolute;width:1px;height:1px;overflow:hidden;clip-path:inset(50%)}.solution-trace tr{border:1px solid var(--line);padding:10px;margin:12px 0}.solution-trace td{border:0;padding:8px 0}.trace-mobile-label{display:block;font-size:14px;font-weight:650;margin-bottom:3px}.solution-trace .reasoning-role{font-size:14px}.solution-matrix .matrix-scroll th,.solution-matrix .matrix-scroll td{min-width:36px;padding:6px}.structured-solution h3{font-size:24px}.solution-step h4{font-size:21px}}
@media print{.reasoning-page .reasoning-role,.reasoning-page .solution-step,.reasoning-page .solution-conclusion{--cue-ink:currentColor;--cue-paper:transparent}.reasoning-page .matrix-focus{background:transparent;outline-color:currentColor}.reasoning-page .trace-focus{outline-color:currentColor}.colour-cue-control{display:none}.solution-matrix,.solution-trace tr{break-inside:avoid}.solution-matrix .matrix-scroll{overflow:visible}.reasoning-page .topbar{position:static}}
@media(forced-colors:active){.reasoning-page .reasoning-role,.reasoning-page .solution-step,.reasoning-page .solution-conclusion{--cue-ink:CanvasText;--cue-paper:Canvas}.reasoning-page .matrix-focus{background:Canvas;outline-color:CanvasText}.reasoning-page .trace-focus{outline-color:CanvasText}}
/* Interactive mathematical models: semantic strokes and native controls. */
.diagram-panel{--diagram-focus:#315a73;--diagram-result:#255c48;--diagram-why:#765428;margin:24px 0;padding:20px;border:1px solid var(--line);min-width:0;scroll-margin-top:90px}.diagram-module{min-width:0}.diagram-module h2{margin-top:8px}.diagram-module p{overflow-wrap:break-word}.math-diagram{width:100%;max-width:680px;height:auto;display:block;margin:16px auto;color:var(--ink);overflow:visible}.math-diagram text{font:24px var(--sans);fill:currentColor;stroke:var(--paper,#f7f5ef);stroke-width:4px;paint-order:stroke fill}.math-diagram line,.math-diagram path{vector-effect:non-scaling-stroke}.prim-svg line{stroke:currentColor;stroke-width:1.5;stroke-dasharray:5 3}.prim-svg .edge-chosen line{stroke:var(--diagram-result);stroke-width:4;stroke-dasharray:none}.prim-svg circle,.dfa-node,.set-boundary{fill:var(--paper,#f7f5ef);stroke:currentColor;stroke-width:2}.prim-svg .node-visited circle{stroke:var(--diagram-result);stroke-width:4}.prim-svg .node-marker{font-size:20px}.diagram-state{border:2px solid var(--diagram-focus);padding:12px}.diagram-result{border-bottom:4px double var(--diagram-result);padding:12px 0}.diagram-why{border-left:3px solid var(--diagram-why);padding:4px 14px;margin:16px 0}.diagram-feedback{border-left:3px solid currentColor;padding:12px;margin:12px 0}.diagram-edge-actions{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:8px}.diagram-module .btn{white-space:normal;overflow-wrap:break-word;min-height:44px}.diagram-module .action-row{margin:16px 0;gap:10px;flex-wrap:wrap}.diagram-module input[type=text],.diagram-module select{font:inherit;padding:10px;max-width:100%;width:100%;border:1px solid var(--line);background:var(--paper,#f7f5ef);color:var(--ink)}.diagram-module input[type=checkbox]{width:22px;height:22px;margin:10px;accent-color:var(--green)}.diagram-controls{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:14px}.diagram-module label{display:block}.diagram-module :focus-visible{outline:3px solid var(--diagram-focus);outline-offset:4px}.diagram-regions{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:10px}.diagram-regions p{padding:10px;border:1px solid var(--line);margin:0}.region-in-result{border-bottom:4px double currentColor!important}.universe-boundary{fill:none;stroke:currentColor;stroke-width:2}.sets-svg .set-boundary{fill:none}.selected-element{fill:var(--paper,#f7f5ef);stroke:var(--diagram-focus);stroke-width:3}.sets-svg .set-token{stroke-width:5px}.membership-table,.identity-table{width:100%;border-collapse:collapse;margin:18px 0;font-size:16px}.membership-table td,.membership-table th,.identity-table td,.identity-table th{padding:8px;border:1px solid var(--line);text-align:left;word-break:normal}.membership-table caption,.identity-table caption{text-align:left;margin-bottom:10px}.case-focus{outline:2px solid var(--diagram-focus);outline-offset:-2px}.diagram-chain{overflow-wrap:anywhere}.transition-neutral,.transition-current{fill:none;stroke:currentColor;stroke-width:2}.transition-current{stroke:var(--diagram-focus);stroke-width:5}.state-halo{fill:none;stroke:var(--diagram-focus);stroke-width:3;stroke-dasharray:6 4}.diagram-trace li{overflow-wrap:anywhere;margin:10px 0}.diagram-module code{font-size:1em;white-space:normal;overflow-wrap:anywhere}.diagram-panel[data-colour-cues=off],.reasoning-page[data-colour-cues=off] .diagram-panel{--diagram-focus:var(--ink);--diagram-result:var(--ink);--diagram-why:var(--ink)}
@media(max-width:600px){.diagram-panel{padding:12px}.diagram-controls{grid-template-columns:1fr}.diagram-edge-actions{grid-template-columns:repeat(2,minmax(0,1fr))}.diagram-regions{grid-template-columns:1fr}.membership-table td,.membership-table th,.identity-table td,.identity-table th{padding:5px}.diagram-module input[type=checkbox]{margin:6px}.dfa-svg text{font-size:30px}}
@media print,(forced-colors:active){.diagram-panel{--diagram-focus:currentColor;--diagram-result:currentColor;--diagram-why:currentColor}.math-diagram text{stroke:none}.selected-element,.dfa-node,.prim-svg circle{fill:Canvas}.math-diagram{break-inside:avoid}}
@media(prefers-reduced-motion:reduce){.diagram-panel *{animation:none!important;transition:none!important;scroll-behavior:auto!important}}
.diagram-module table th{text-transform:none;letter-spacing:normal}.diagram-module table caption{font-size:16px}
@media(max-width:600px){.prim-svg text,.sets-svg text{font-size:30px}.prim-svg .node-marker{font-size:27px}}
.diagram-module td,.diagram-module th{min-width:0;max-width:none}.membership-table{table-layout:fixed}.membership-table th:first-child{width:12%}.membership-table th:nth-child(2),.membership-table th:nth-child(3){width:20%}.diagram-module summary{font-size:16px}.diagram-module .quiet{font-size:14px}
.diagram-module table th{font-size:16px}.identity-table{table-layout:fixed}.identity-table th{width:25%}
@media(max-width:600px){.identity-table th,.identity-table td{padding:5px 3px}}
.diagram-ready{border:0;margin:0;padding:0;min-width:0}

/* Aligned topic columns; the actual available content width controls stacking. */
#term-results{container-type:inline-size;--glossary-columns:minmax(0,.85fr) minmax(0,1fr) minmax(0,1.35fr)}
.glossary-group>h2{color:var(--glossary-accent)}
.glossary-columns-heading,.glossary-entry{display:grid;grid-template-columns:var(--glossary-columns);column-gap:22px;padding:18px 24px}
.glossary-columns-heading{font-size:14px;font-weight:650;padding-top:12px;padding-bottom:12px;border-bottom:1px solid var(--line)}
.glossary-list{display:block}
.glossary-subheading{font:600 14px/1.5 var(--sans);text-transform:none;letter-spacing:normal;margin:22px 24px 8px;color:var(--muted)}
.glossary-entry{row-gap:12px}
.glossary-heading{display:flex;flex-direction:column;align-items:flex-start;gap:8px;margin:0;min-width:0}
.glossary-heading .glossary-symbol,.glossary-heading .glossary-abbreviation{min-width:0;max-width:100%;overflow:visible}
.glossary-heading .symbol{display:block;font:600 30px/1.3 var(--serif);color:var(--glossary-accent);white-space:normal;border:0;padding:0;width:auto;max-width:100%;word-break:normal;overflow-wrap:normal}
.glossary-heading .glossary-term{min-width:0;max-width:100%}
.glossary-entry h2{font:600 20px/1.35 var(--sans);margin:0}
.glossary-entry .glossary-reading{color:var(--muted);font-size:14px;line-height:1.5;margin:4px 0 0}
.glossary-entry p{font-size:16px;line-height:1.6;margin:0 0 8px;word-break:normal;overflow-wrap:normal}
.glossary-entry p:last-child{margin-bottom:0}
.glossary-text-row{display:block;min-width:0;padding:0}
.glossary-text-row>div{min-width:0}
.glossary-entry .glossary-text-row h3{position:absolute;width:1px;height:1px;overflow:hidden;clip-path:inset(50%);font:600 14px/1.8 var(--sans);margin:0;text-transform:none;letter-spacing:normal}
.glossary-entry .glossary-example-block,.glossary-entry .glossary-why{background:transparent;border:0;margin:0;padding:0}
.glossary-entry .glossary-why{margin-top:10px}
.glossary-formula{grid-column:1/-1;font:22px/1.8 var(--serif);color:var(--glossary-accent);max-width:100%;min-width:0;margin:0;padding:10px 0 0;border-top:1px solid var(--line);border-bottom:0;overflow:visible;word-break:normal;overflow-wrap:normal;white-space:normal}
.glossary-formula-line{display:block;max-width:100%;white-space:normal}
.glossary-entry .glossary-links{grid-column:1/-1;display:flex;flex-wrap:wrap;gap:6px 22px;margin:0;padding-top:6px}
.glossary-entry .glossary-links p{font-size:14px;line-height:1.6}
.glossary-extra{margin:8px 0!important}.glossary-extra>p{margin-top:10px}
#term-results[data-colour-cues="off"] .glossary-group{--glossary-accent:var(--ink)!important}
@container(max-width:720px){
 .glossary-columns-heading{display:none}
 .glossary-entry{display:block;padding:16px}
 .glossary-subheading{margin-left:16px;margin-right:16px}
 .glossary-heading{flex-direction:row;flex-wrap:wrap;align-items:flex-start;gap:10px 12px;margin-bottom:10px}
 .glossary-heading .glossary-term{flex:1 1 160px}
 .glossary-heading .symbol{font-size:28px}
 .glossary-entry h2{font-size:19px}
 .glossary-text-row{padding:8px 0}
 .glossary-entry .glossary-text-row h3{position:static;width:auto;height:auto;clip-path:none;overflow:visible;margin-bottom:4px}
 .glossary-entry .glossary-example-block{padding-top:10px}
 .glossary-formula{font-size:20px;line-height:1.8;margin-top:12px}
 .glossary-entry .glossary-links{margin-top:12px;gap:6px 16px}
}
/* Result and reasoning remain visible as distinct, wrapping fields. */
.growing-textarea,.trainer-card textarea.growing-textarea{display:block;width:100%;max-width:100%;min-width:0;box-sizing:border-box;resize:vertical;overflow:hidden;white-space:pre-wrap;overflow-wrap:anywhere;line-height:1.6;min-height:0}
.trainer-reasoning{margin-top:24px;padding-top:18px;border-top:1px solid var(--line)}
.answer-format{font-size:16px}.official-condition{font-size:16px;line-height:1.7;min-width:0;overflow-wrap:normal;word-break:normal}.official-condition p{font-size:16px;line-height:1.7}.official-condition li{padding:4px 0}.official-condition ol{padding-left:24px}.official-math{font:20px/1.8 var(--serif);margin:14px 0;overflow-wrap:normal}.official-op{display:inline-grid;grid-template-rows:auto auto auto;vertical-align:middle;text-align:center;line-height:1.15;margin:4px 5px}.official-op>span{font-size:30px}.official-op sup,.official-op sub{position:static;font:14px/1.2 var(--sans)}.official-source{margin-top:18px}.assignment-attempt textarea{min-height:180px}.assignment-reading,.assignment-attempt{min-width:0}.official-condition sup,.official-condition sub{line-height:0}
@media(max-width:700px){.official-math{font-size:18px}.official-condition ol{padding-left:22px}}
.official-condition .official-op sup,.official-condition .official-op sub{line-height:1.2}
/* Proof help reuses native disclosures and the existing reading rhythm. */
.method-reference,.official-guidance{margin:20px 0;min-width:0}.method-reference>details{margin:12px 0;padding-left:12px;border-left:2px solid var(--line)}.method-reference p,.pedagogical-solution p{font-size:16px;line-height:1.7}.pedagogical-steps{padding-left:24px}.pedagogical-steps>li{margin:20px 0;min-width:0}.pedagogical-steps p{margin:8px 0}.step-reason{border-left:2px solid var(--line);padding-left:12px}.proof-status{display:block;font-size:14px;margin-bottom:8px}.proof-math{font-size:18px;line-height:2;max-width:100%;margin:10px 0;overflow-wrap:normal}.proof-math .katex{white-space:normal}.proof-table{max-width:100%;overflow-x:auto}.proof-table table{width:100%;border-collapse:collapse}.proof-table th,.proof-table td{padding:8px;text-align:left;border-bottom:1px solid var(--line)}.solution-part{margin-top:22px}.official-hints:empty{display:none}
.depth-prerequisites{margin:0 0 20px;padding:14px 16px;border:1px solid var(--line);border-radius:4px;background:var(--paper)}.depth-prerequisites>summary{font-size:15px}.depth-prerequisite-list{display:grid;gap:12px;margin-top:14px}.depth-prerequisite-list section{padding:14px;background:var(--white);border-left:3px solid var(--green)}.depth-prerequisite-list h4,.depth-prerequisite-list p{margin:5px 0}.depth-prerequisite-list .source-line{margin-top:9px}.depth-brief{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:12px;margin:18px 0}.depth-brief>div{padding:14px;background:var(--paper);border-top:3px solid var(--green);min-width:0}.depth-brief h4,.depth-brief p{margin:4px 0}.walkthrough-method,.depth-conclusion,.depth-error-analysis{margin:22px 0;padding:16px 18px;background:var(--paper);border-radius:4px}.depth-statement{font:19px/1.7 var(--serif)}.argument-purpose{padding-left:14px;border-left:2px solid #c99d70;color:var(--muted)}.clean-answer{font:20px/1.75 var(--serif);padding:14px 16px;background:#e8efdd;border-left:3px solid var(--green);overflow-x:auto}.depth-error-analysis{background:#f5e9df}.depth-understanding-check,.depth-alternatives details{margin-top:18px;padding:14px 16px;border:1px solid var(--line);border-radius:4px}.depth-understanding-check>summary,.depth-alternatives details>summary{font-size:15px}.depth-alternatives{margin-top:26px}.trainer-card label{position:relative;z-index:1}.trainer-card textarea:focus-visible{outline:2px solid #ad683d;outline-offset:2px}
@media(max-width:600px){.method-reference>details{padding-left:8px}.pedagogical-steps{padding-left:20px}.proof-math{font-size:17px}.depth-brief{grid-template-columns:1fr}.walkthrough-method,.depth-conclusion,.depth-error-analysis{padding:14px}.depth-statement{font-size:18px}}

/* Official solution tables retain every column; keyboard scrolling stays local. */
.official-guidance .proof-table table{table-layout:auto;min-width:max-content}.official-guidance .proof-table th,.official-guidance .proof-table td{white-space:nowrap;text-align:center;min-width:0;max-width:none;font-size:16px;text-transform:none;letter-spacing:normal}.official-guidance .proof-table caption{text-align:left;white-space:normal;padding:8px 0;font-weight:600;font-size:16px}.official-guidance .source-clarification{border-left:2px solid var(--line);padding-left:12px}

/* Reserve room between labels and the visible field focus ring. */
.growing-textarea,textarea[data-math-entry]{margin-block-start:8px}

/* Authored mathematics stays readable without widening the exercise card. */
.math-display{display:block;max-width:100%;overflow-x:auto;overflow-y:hidden;margin:1em 0;padding:.25em 0;white-space:normal;overflow-wrap:normal}.math-display .katex-display{margin:0;text-align:left}.math-display .katex-display>.katex{text-align:left;white-space:nowrap}.math-inline{white-space:normal}.depth-steps>li,.depth-conclusion,.depth-alternatives{min-width:0}.clean-answer{white-space:pre-wrap}