:root{
  --bg:#07111f;--bg2:#0b1728;--panel:rgba(14,30,49,.78);--panel-solid:#10233a;
  --text:#eef7ff;--muted:#9db1c7;--line:rgba(255,255,255,.11);
  --cyan:#55d6ff;--violet:#907cff;--green:#64e6b3;--orange:#ffb66e;--red:#ff7f8f;
  --shadow:0 24px 70px rgba(0,0,0,.28);--radius:24px;--radius-sm:16px;
  --sidebar:268px;--topbar:76px;
}
body.light{
  --bg:#f5f8fc;--bg2:#edf3fb;--panel:rgba(255,255,255,.88);--panel-solid:#fff;
  --text:#122033;--muted:#607289;--line:rgba(18,32,51,.12);
  --shadow:0 22px 60px rgba(36,69,103,.10);
}
*{box-sizing:border-box}
html{scroll-behavior:smooth;scroll-padding-top:92px}
body{margin:0;background:radial-gradient(circle at 80% 0%,rgba(144,124,255,.12),transparent 26%),linear-gradient(180deg,var(--bg),var(--bg2));color:var(--text);font-family:Inter,ui-sans-serif,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;line-height:1.6;min-height:100vh}
a{color:inherit;text-decoration:none}
button{font:inherit}
.bg-orb{position:fixed;border-radius:50%;filter:blur(100px);pointer-events:none;z-index:-1;opacity:.18}
.orb-a{width:400px;height:400px;background:#2cc7ff;top:5%;right:5%}
.orb-b{width:420px;height:420px;background:#9c74ff;bottom:3%;left:18%}
.topbar{height:var(--topbar);position:fixed;top:0;left:0;right:0;z-index:20;background:color-mix(in srgb,var(--bg) 82%,transparent);backdrop-filter:blur(18px);border-bottom:1px solid var(--line);display:flex;align-items:center;justify-content:space-between;padding:0 22px}
.brand{display:flex;align-items:center;gap:12px}
.brand-mark{width:42px;height:42px;border-radius:14px;background:linear-gradient(135deg,var(--cyan),var(--violet));display:grid;place-items:center;color:#06121d;font-weight:900;font-size:22px;box-shadow:0 9px 28px rgba(85,214,255,.25)}
.brand strong,.brand small{display:block}
.brand strong{font-size:16px}
.brand small{font-size:11px;color:var(--muted);margin-top:-3px}
.top-actions{display:flex;gap:8px}
.icon-btn{width:42px;height:42px;border-radius:13px;border:1px solid var(--line);background:var(--panel);color:var(--text);cursor:pointer}
.menu-btn{display:none}
.sidebar{position:fixed;z-index:15;top:var(--topbar);bottom:0;left:0;width:var(--sidebar);padding:20px 14px 18px;background:color-mix(in srgb,var(--bg) 86%,transparent);backdrop-filter:blur(18px);border-right:1px solid var(--line);overflow:auto;display:flex;flex-direction:column;justify-content:space-between}
.sidebar nav{display:flex;flex-direction:column;gap:4px}
.nav-link{padding:9px 11px;border-radius:12px;color:var(--muted);display:flex;align-items:center;gap:10px;font-size:13px;transition:.2s}
.nav-link span{width:24px;height:24px;border-radius:8px;background:rgba(255,255,255,.05);display:grid;place-items:center;font-size:11px}
.nav-link:hover,.nav-link.active{background:linear-gradient(90deg,rgba(85,214,255,.14),rgba(144,124,255,.08));color:var(--text)}
.nav-link.active span{background:var(--cyan);color:#06121d;font-weight:800}
.nav-group{font-size:10px;letter-spacing:.16em;color:var(--muted);opacity:.7;margin:14px 10px 5px}
.side-progress{border-top:1px solid var(--line);padding:14px 10px 2px}
.progress-label{display:flex;justify-content:space-between;font-size:12px}
.progress-track{height:7px;background:rgba(255,255,255,.08);border-radius:99px;overflow:hidden;margin:8px 0}
.progress-fill{height:100%;width:0;background:linear-gradient(90deg,var(--cyan),var(--violet));transition:.4s}
.side-progress small{color:var(--muted);font-size:10px}
.content{margin-left:var(--sidebar);padding-top:var(--topbar);width:calc(100% - var(--sidebar))}
.page-section,.final-map{max-width:1160px;margin:0 auto;padding:82px 44px;border-bottom:1px solid var(--line)}
.hero-section{min-height:calc(100vh - var(--topbar));display:grid;grid-template-columns:1.05fr .95fr;gap:46px;align-items:center;position:relative}
.eyebrow{text-transform:uppercase;letter-spacing:.15em;font-size:11px;font-weight:800;color:var(--cyan)}
h1,h2,h3,p{margin-top:0}
h1{font-size:clamp(42px,5.2vw,76px);line-height:1.02;letter-spacing:-.045em;margin:15px 0 22px}
h1 em{font-style:normal;background:linear-gradient(100deg,var(--cyan),var(--violet));-webkit-background-clip:text;background-clip:text;color:transparent}
h2{font-size:clamp(34px,4vw,52px);line-height:1.06;letter-spacing:-.035em;margin:10px 0 14px}
h3{letter-spacing:-.02em}
.lead{font-size:18px;color:var(--muted);max-width:720px}
.hero-actions{display:flex;gap:12px;margin:30px 0}
.btn{border:1px solid var(--line);padding:12px 18px;border-radius:14px;cursor:pointer;display:inline-flex;align-items:center;justify-content:center;font-weight:750;transition:.2s}
.btn:hover{transform:translateY(-1px)}
.btn.primary{background:linear-gradient(135deg,var(--cyan),#74bfff);color:#06121d;border-color:transparent}
.btn.secondary{background:var(--panel);color:var(--text)}
.hero-kpis{display:flex;gap:30px}
.hero-kpis div{display:flex;flex-direction:column}
.hero-kpis strong{font-size:24px}.hero-kpis span{font-size:11px;color:var(--muted);text-transform:uppercase;letter-spacing:.12em}
.hero-visual{height:500px;position:relative;border-radius:32px;border:1px solid var(--line);background:linear-gradient(145deg,rgba(85,214,255,.08),rgba(144,124,255,.1));box-shadow:var(--shadow);overflow:hidden}
.hero-visual svg{position:absolute;width:82%;height:70%;left:7%;bottom:2%;color:var(--text)}
.formula-card{position:absolute;z-index:2;padding:12px 16px;border-radius:14px;background:color-mix(in srgb,var(--panel-solid) 84%,transparent);backdrop-filter:blur(12px);border:1px solid var(--line);box-shadow:0 12px 30px rgba(0,0,0,.16);font-size:14px}
.fc1{top:6%;left:7%}.fc2{top:27%;right:5%}.fc3{bottom:22%;left:5%}.fc4{bottom:5%;right:7%}
.concept-strip{grid-column:1/-1;border:1px solid var(--line);background:var(--panel);padding:16px 22px;border-radius:18px;display:flex;justify-content:space-between;gap:20px;color:var(--muted)}
.concept-strip strong{color:var(--text)}
.section-heading{max-width:800px;margin-bottom:38px}
.section-heading p{color:var(--muted);font-size:17px}
.classification-tree{position:relative}
.tree-root{width:max-content;margin:0 auto 24px;padding:10px 24px;border-radius:14px;background:linear-gradient(135deg,var(--cyan),var(--violet));color:#06121d;font-weight:900}
.tree-branches{display:grid;grid-template-columns:1fr 1fr;gap:22px}
.tree-card,.theory-card,.mini-card,.worked-example,.algorithm-box,.training-card,.quiz-card{background:var(--panel);border:1px solid var(--line);border-radius:var(--radius);box-shadow:var(--shadow)}
.tree-card{padding:26px}
.tree-icon{width:46px;height:46px;border-radius:15px;background:rgba(85,214,255,.12);display:grid;place-items:center;color:var(--cyan);font-weight:900}
.tree-card h3{font-size:24px;margin:14px 0 4px}
.tree-card>p{color:var(--muted)}
.subtree{display:grid;gap:9px;margin-top:16px}
.subtree div{padding:12px 14px;border:1px solid var(--line);border-radius:13px;display:grid;grid-template-columns:1.3fr 1fr;align-items:center}
.subtree div strong{font-size:13px}.subtree div span{text-align:right}.subtree div small{grid-column:1/-1;color:var(--muted)}
.callout{margin:22px 0;display:flex;gap:14px;border:1px solid rgba(255,182,110,.25);background:rgba(255,182,110,.08);padding:16px 18px;border-radius:18px}
.callout-icon{min-width:34px;height:34px;border-radius:10px;background:var(--orange);color:#281705;display:grid;place-items:center;font-weight:900}
.mini-grid,.theory-grid{display:grid;grid-template-columns:1fr 1fr;gap:18px}
.theory-grid.three{grid-template-columns:repeat(3,1fr)}
.mini-card,.theory-card{padding:22px}
.tag{font-size:10px;letter-spacing:.15em;text-transform:uppercase;color:var(--cyan);font-weight:800}
.math-lg{font-size:20px;margin:14px 0;overflow-x:auto;padding-bottom:4px}
.steps{display:grid;gap:11px}
.step-card{display:flex;gap:16px;align-items:flex-start;padding:16px 18px;border:1px solid var(--line);border-radius:18px;background:rgba(255,255,255,.025)}
.step-card>span{min-width:38px;height:38px;border-radius:12px;background:linear-gradient(135deg,var(--cyan),var(--violet));display:grid;place-items:center;color:#06121d;font-weight:900}
.step-card h3{margin:0 0 2px}.step-card p{margin:0;color:var(--muted)}
.algorithm-box{margin:24px 0;padding:24px}
.algorithm-head{display:flex;justify-content:space-between;margin-bottom:18px}.algorithm-head small{color:var(--muted)}
.algorithm-flow{display:flex;gap:8px;align-items:stretch}
.algorithm-flow div{flex:1;border:1px solid var(--line);padding:12px;border-radius:14px;font-size:12px;color:var(--muted);display:flex;flex-direction:column;gap:6px;justify-content:center}
.algorithm-flow strong{color:var(--text);font-size:14px}.algorithm-flow i{align-self:center;color:var(--cyan);font-style:normal}
.worked-example{padding:24px;margin:22px 0}
.worked-example.compact{padding:20px}
.worked-title{display:flex;align-items:center;justify-content:space-between;gap:20px;border-bottom:1px solid var(--line);padding-bottom:14px;margin-bottom:14px}
.worked-title span{color:var(--cyan);font-size:11px;text-transform:uppercase;letter-spacing:.13em;font-weight:800}
.worked-title h3{margin:0;font-size:21px}
.worked-example ol{margin:0;padding-left:22px}.worked-example li{padding:5px 0}
.complete-btn{margin-top:20px;border:1px dashed var(--line);background:transparent;color:var(--muted);padding:10px 14px;border-radius:12px;cursor:pointer}
.complete-btn.done{background:rgba(100,230,179,.12);border-style:solid;border-color:rgba(100,230,179,.3);color:var(--green)}
.topic-hero{display:flex;justify-content:space-between;align-items:center;gap:30px;margin-bottom:26px}
.topic-num{display:inline-grid;place-items:center;width:34px;height:34px;border-radius:11px;background:rgba(85,214,255,.1);color:var(--cyan);font-weight:900;margin-right:10px}
.topic-hero h2{margin:8px 0}
.topic-hero p{color:var(--muted);margin:0}
.rule-pill{padding:18px 22px;border-radius:18px;background:linear-gradient(135deg,rgba(85,214,255,.12),rgba(144,124,255,.13));border:1px solid var(--line);white-space:nowrap}
.warning{border-color:rgba(255,182,110,.26)}
.examples-row{display:grid;grid-template-columns:1fr 1fr;gap:14px;margin:18px 0}
.examples-row article{border:1px solid var(--line);border-radius:16px;padding:16px}
.examples-row span{font-size:10px;text-transform:uppercase;letter-spacing:.12em;color:var(--muted)}
.examples-row div{font-size:18px;margin:6px 0}
.practice-box{margin:28px 0 0;padding:22px;border-radius:22px;background:linear-gradient(145deg,rgba(85,214,255,.055),rgba(144,124,255,.055));border:1px solid var(--line)}
.practice-head{display:flex;justify-content:space-between;align-items:center;gap:15px;margin-bottom:14px}
.practice-head h3{margin:0}.practice-head span{font-size:11px;color:var(--muted)}
.practice-item{padding:14px 0;border-top:1px solid var(--line)}
.practice-q{display:flex;justify-content:space-between;gap:15px;align-items:center}
.practice-q .formula{font-size:18px}
.reveal-btn{border:1px solid var(--line);background:var(--panel);color:var(--text);padding:8px 11px;border-radius:10px;cursor:pointer;white-space:nowrap}
.solution{display:none;margin-top:12px;padding:12px 14px;border-radius:12px;background:rgba(100,230,179,.075);color:var(--muted)}
.solution.show{display:block}.solution strong{color:var(--green)}
.trig-table{display:grid;grid-template-columns:1fr 1fr;gap:12px;margin:20px 0}
.trig-table div{display:flex;flex-direction:column;gap:4px;padding:18px;border:1px solid var(--line);border-radius:16px}
.trig-table span{color:var(--muted);font-size:13px}
.builder-layout{display:grid;grid-template-columns:1fr 1fr;gap:20px}
.builder-controls,.builder-output{padding:22px;background:var(--panel);border:1px solid var(--line);border-radius:var(--radius)}
.check-card{display:flex;gap:12px;align-items:flex-start;padding:12px;border:1px solid var(--line);border-radius:14px;margin:8px 0;cursor:pointer;transition:.2s}
.check-card:hover{background:rgba(85,214,255,.05)}
.check-card input{margin-top:5px;accent-color:var(--cyan)}
.check-card span{display:flex;flex-direction:column}.check-card small{color:var(--muted)}
.constraint-list{display:grid;gap:10px;margin:18px 0}
.constraint-item{padding:13px 14px;border-radius:13px;border-left:3px solid var(--cyan);background:rgba(85,214,255,.06)}
.constraint-item small{display:block;color:var(--muted)}
.empty-state{color:var(--muted);border:1px dashed var(--line);padding:18px;border-radius:14px}
.intersection-box{margin-top:18px;padding:16px;border-radius:15px;background:linear-gradient(135deg,rgba(85,214,255,.1),rgba(144,124,255,.1));display:flex;flex-direction:column}
.intersection-box span,.intersection-box small{color:var(--muted)}
.level-tabs{display:flex;gap:8px;margin-bottom:18px}
.level-btn{border:1px solid var(--line);background:var(--panel);color:var(--muted);padding:9px 15px;border-radius:12px;cursor:pointer}
.level-btn.active{background:var(--cyan);color:#06121d;border-color:transparent;font-weight:800}
.training-card{padding:26px;min-height:330px}
.training-meta{display:flex;justify-content:space-between;color:var(--muted);font-size:12px}
.training-formula{font-size:27px;margin:30px 0;text-align:center;overflow-x:auto}
.answer-options{display:grid;gap:9px}
.answer-option{border:1px solid var(--line);background:transparent;color:var(--text);padding:12px 14px;border-radius:13px;text-align:left;cursor:pointer}
.answer-option:hover{background:rgba(85,214,255,.05)}
.answer-option.correct{border-color:rgba(100,230,179,.5);background:rgba(100,230,179,.1)}
.answer-option.wrong{border-color:rgba(255,127,143,.5);background:rgba(255,127,143,.1)}
.feedback-box{margin-top:16px;padding:14px;border-radius:14px;background:rgba(255,255,255,.035);display:none}
.feedback-box.show{display:block}
.training-nav{display:flex;align-items:center;justify-content:space-between;margin-top:14px}
.quiz-container{display:grid;gap:14px}
.quiz-card{padding:20px}
.quiz-card h3{font-size:16px;margin-bottom:14px}
.quiz-options{display:grid;gap:8px}
.quiz-option{display:flex;gap:9px;padding:10px 12px;border:1px solid var(--line);border-radius:12px;cursor:pointer}
.quiz-option input{accent-color:var(--cyan)}
.quiz-card.correct{border-color:rgba(100,230,179,.45)}.quiz-card.wrong{border-color:rgba(255,127,143,.5)}
.quiz-explain{display:none;margin-top:12px;color:var(--muted);font-size:13px}.quiz-explain.show{display:block}
.quiz-footer{display:flex;gap:10px;margin:20px 0}
.quiz-result{padding:22px;border:1px solid var(--line);border-radius:20px;background:var(--panel)}
.quiz-result.hidden{display:none}
.score-big{font-size:46px;font-weight:900;background:linear-gradient(90deg,var(--cyan),var(--violet));-webkit-background-clip:text;background-clip:text;color:transparent}
.cheatsheet{display:grid;grid-template-columns:repeat(2,1fr);gap:10px}
.cheatsheet div{display:grid;grid-template-columns:1.1fr 1fr 1.2fr;align-items:center;gap:10px;border:1px solid var(--line);border-radius:14px;padding:13px 15px}
.cheatsheet span{font-size:12px;color:var(--muted)}.cheatsheet em{font-style:normal;color:var(--green)}
footer{max-width:1160px;margin:0 auto;padding:34px 44px 60px;color:var(--muted);font-size:12px}
footer strong{color:var(--text)}.footer-note{font-size:11px}
.to-top{position:fixed;right:18px;bottom:18px;width:42px;height:42px;border-radius:14px;border:1px solid var(--line);background:var(--panel-solid);color:var(--text);cursor:pointer;opacity:0;pointer-events:none;transition:.2s;z-index:30}
.to-top.show{opacity:1;pointer-events:auto}

@media(max-width:1050px){
  :root{--sidebar:230px}
  .hero-section{grid-template-columns:1fr}.hero-visual{height:420px}
  .theory-grid.three{grid-template-columns:1fr}
  .algorithm-flow{flex-wrap:wrap}.algorithm-flow div{min-width:150px}.algorithm-flow i{display:none}
}
@media(max-width:820px){
  :root{--topbar:68px}
  .menu-btn{display:block}
  .sidebar{transform:translateX(-104%);transition:.25s;width:min(82vw,310px);box-shadow:var(--shadow)}
  .sidebar.open{transform:translateX(0)}
  .content{margin-left:0;width:100%}
  .page-section,.final-map{padding:64px 22px}
  .hero-section{padding-top:40px;min-height:auto}
  .hero-visual{height:380px}
  .tree-branches,.mini-grid,.theory-grid,.examples-row,.builder-layout,.trig-table,.cheatsheet{grid-template-columns:1fr}
  .topic-hero{align-items:flex-start;flex-direction:column}.rule-pill{white-space:normal;width:100%}
  .concept-strip{flex-direction:column;gap:4px}
  .worked-title{align-items:flex-start;flex-direction:column;gap:5px}
  .cheatsheet div{grid-template-columns:1fr}
}
@media(max-width:520px){
  h1{font-size:42px}
  .brand small{display:none}
  .hero-actions{flex-direction:column}
  .hero-kpis{justify-content:space-between;gap:8px}
  .hero-visual{height:350px}
  .formula-card{font-size:11px;padding:9px 10px}
  .fc2{top:23%}.fc3{bottom:26%}
  .training-nav .btn{padding:10px 11px;font-size:12px}
  .practice-q{align-items:flex-start;flex-direction:column}
  .level-tabs{overflow-x:auto}
}


/* DominioLab v2 */
.version-badge{font-size:9px;vertical-align:top;margin-left:4px;padding:2px 5px;border-radius:7px;background:linear-gradient(135deg,var(--cyan),var(--violet));color:#06121d}
.hidden{display:none!important}
.tutor-shell,.worksheet-controls,.worksheet-preview,.corrector-tools,.print-sheet{background:var(--panel);border:1px solid var(--line);border-radius:var(--radius);box-shadow:var(--shadow)}
.tutor-shell{padding:24px}
.tutor-top{display:flex;justify-content:space-between;align-items:flex-start;gap:20px;padding-bottom:18px;border-bottom:1px solid var(--line)}
.tutor-formula{font-size:28px;margin-top:12px;overflow-x:auto}
.tutor-count{min-width:70px;text-align:center;padding:8px 12px;border:1px solid var(--line);border-radius:12px;color:var(--muted)}
.tutor-stage{margin-top:20px;padding:20px;border:1px solid var(--line);border-radius:18px;background:rgba(255,255,255,.022);transition:.25s}
.tutor-stage.locked{opacity:.48;pointer-events:none;filter:saturate(.5)}
.stage-label{display:flex;gap:12px;align-items:flex-start;margin-bottom:16px}
.stage-label>span{min-width:34px;height:34px;border-radius:11px;background:linear-gradient(135deg,var(--cyan),var(--violet));color:#06121d;font-weight:900;display:grid;place-items:center}
.stage-label div{display:flex;flex-direction:column}.stage-label small{color:var(--muted)}
.tutor-choices{display:grid;grid-template-columns:repeat(2,1fr);gap:9px}
.tutor-choice{display:flex;align-items:center;gap:9px;padding:11px 12px;border:1px solid var(--line);border-radius:12px;cursor:pointer}
.tutor-choice input{accent-color:var(--cyan)}
.inline-actions{display:flex;gap:9px;margin-top:16px;flex-wrap:wrap}
.tutor-hint{margin-top:14px;padding:13px 15px;border-radius:13px;background:rgba(255,182,110,.08);border:1px solid rgba(255,182,110,.22);color:var(--muted)}
.tutor-solution{margin-top:20px;padding:20px;border-radius:18px;background:linear-gradient(135deg,rgba(100,230,179,.07),rgba(85,214,255,.05));border:1px solid rgba(100,230,179,.22)}
.solution-steps{display:grid;gap:10px;counter-reset:step}
.solution-step{display:grid;grid-template-columns:30px 1fr;gap:11px;align-items:start;padding:12px 14px;border-radius:13px;background:rgba(255,255,255,.03);border:1px solid var(--line)}
.solution-step:before{counter-increment:step;content:counter(step);width:28px;height:28px;border-radius:9px;background:rgba(85,214,255,.12);color:var(--cyan);display:grid;place-items:center;font-size:12px;font-weight:900}

.worksheet-builder{display:grid;gap:20px}
.worksheet-controls{padding:22px}
.control-grid{display:grid;grid-template-columns:1fr 1fr 1.1fr;gap:14px}
.control-block{display:flex;flex-direction:column;gap:7px;margin-bottom:17px}
.control-block label,.control-block>strong{font-size:13px}
.text-input,.select-input{width:100%;border:1px solid var(--line);background:rgba(255,255,255,.035);color:var(--text);padding:11px 12px;border-radius:12px;outline:none}
.text-input:focus,.select-input:focus{border-color:rgba(85,214,255,.55);box-shadow:0 0 0 3px rgba(85,214,255,.08)}
.select-input option{color:#111}
input[type="range"]{width:100%;accent-color:var(--cyan)}
.category-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:8px;margin-top:4px}
.category-grid label{display:flex;gap:8px;align-items:center;padding:9px 10px;border:1px solid var(--line);border-radius:11px;color:var(--muted);cursor:pointer}
.category-grid input{accent-color:var(--cyan)}
.worksheet-actions,.corrector-actions{display:flex;gap:9px;flex-wrap:wrap}
.small-message{font-size:12px;color:var(--muted);margin-top:10px}
.print-sheet{padding:30px;background:#fff;color:#111;box-shadow:0 20px 60px rgba(0,0,0,.14)}
.sheet-header{display:flex;justify-content:space-between;align-items:flex-start;gap:20px;border-bottom:2px solid #172033;padding-bottom:15px}
.sheet-header h3{font-size:25px;margin:5px 0 0;color:#111}
.sheet-kicker{font-size:10px;letter-spacing:.14em;text-transform:uppercase;color:#5c6572;font-weight:800}
.sheet-badge{border:2px solid #172033;border-radius:12px;padding:7px 11px;font-size:11px;font-weight:900;letter-spacing:.13em}
.student-header{display:grid;grid-template-columns:2fr .7fr .8fr;gap:18px;margin:18px 0;font-size:12px}
.sheet-instructions{padding:11px 13px;background:#f1f4f7;border-left:4px solid #172033;border-radius:7px;font-size:12px;margin-bottom:18px}
.worksheet-exercises{display:grid;gap:18px}
.sheet-exercise{break-inside:avoid;page-break-inside:avoid}
.sheet-exercise-head{display:flex;justify-content:space-between;gap:14px;align-items:flex-start}
.sheet-number{font-weight:900;min-width:25px}
.sheet-code{font-size:9px;letter-spacing:.1em;color:#6a7280;border:1px solid #cbd1d8;border-radius:6px;padding:2px 5px;white-space:nowrap}
.sheet-formula{font-size:18px;flex:1;overflow-x:auto}
.work-box{margin-top:12px;border:1px solid #b9c2cc;border-radius:8px;background:#fff;min-height:150px;position:relative;overflow:hidden}
.work-box.large{min-height:205px}
.work-box.grid{background-image:linear-gradient(to right,rgba(117,129,143,.18) 1px,transparent 1px),linear-gradient(to bottom,rgba(117,129,143,.18) 1px,transparent 1px);background-size:18px 18px}
.work-box:before{content:"Spazio di lavoro";position:absolute;top:6px;right:9px;font-size:8px;letter-spacing:.08em;text-transform:uppercase;color:#9ba5b0;background:rgba(255,255,255,.86);padding:2px 5px;border-radius:5px}
.worksheet-space-grid{margin-top:-3px}
.worksheet-tip{justify-content:center;padding:10px 12px;border:1px dashed var(--line);border-radius:12px;margin-bottom:17px}
.worksheet-tip small{color:var(--muted);line-height:1.45}
.sheet-footer{margin-top:24px;padding-top:10px;border-top:1px solid #d7dce1;color:#69717b;font-size:9px}
.corrector-tools{padding:20px;margin-bottom:18px;display:grid;grid-template-columns:1.1fr .9fr;gap:18px;align-items:end}
.code-search{display:flex;flex-direction:column;gap:7px}.code-search small{color:var(--muted)}
.code-row{display:flex;gap:8px}
.code-row .text-input{max-width:260px}
.solution-header{margin-bottom:14px}
.solution-list{display:grid;gap:10px}
.solution-card{border:1px solid #d8dde3;border-radius:12px;background:#fff;color:#111;overflow:hidden;break-inside:avoid;page-break-inside:avoid}
.solution-toggle{width:100%;display:flex;justify-content:space-between;align-items:center;gap:15px;text-align:left;padding:13px 15px;border:0;background:#f6f8fa;color:#111;cursor:pointer}
.solution-toggle strong{display:flex;gap:9px;align-items:center}
.solution-toggle span:last-child{font-size:11px;color:#69717b}
.solution-body{display:none;padding:15px}
.solution-card.open .solution-body{display:block}
.solution-domain{margin-top:12px;padding:10px 12px;border-radius:9px;background:#eef9f4;border-left:4px solid #24976d}
.search-solution{margin:18px 0;padding:20px;background:var(--panel);border:1px solid var(--line);border-radius:18px}
.search-solution .solution-card{margin-top:12px}
.empty-solutions{color:#6b7280;padding:18px;border:1px dashed #cbd1d8;border-radius:10px}
@media(max-width:820px){
  .control-grid,.corrector-tools{grid-template-columns:1fr}
  .category-grid{grid-template-columns:1fr 1fr}
  .student-header{grid-template-columns:1fr}
  .tutor-choices{grid-template-columns:1fr}
}
@media(max-width:520px){
  .category-grid{grid-template-columns:1fr}
  .code-row{flex-direction:column}
  .code-row .text-input{max-width:none}
}
@media print{
  @page{size:A4;margin:14mm}
  body.print-worksheet,body.print-solutions{background:#fff!important}
  body.print-worksheet *{visibility:hidden!important}
  body.print-worksheet #worksheetPrint,body.print-worksheet #worksheetPrint *{visibility:visible!important}
  body.print-solutions *{visibility:hidden!important}
  body.print-solutions #solutionsPrint,body.print-solutions #solutionsPrint *{visibility:visible!important}
  body.print-worksheet #worksheetPrint,body.print-solutions #solutionsPrint{
    position:absolute!important;left:0!important;top:0!important;width:100%!important;
    padding:0!important;margin:0!important;border:0!important;box-shadow:none!important;border-radius:0!important;
  }
  .print-sheet{font-family:Arial,Helvetica,sans-serif!important}
  .sheet-exercise{margin-bottom:13mm}
  .solution-card{break-inside:avoid;page-break-inside:avoid}
}


/* v3 - potenze e rendering/formule */
.power-alert{margin:20px 0;padding:20px 22px;border-radius:20px;border:1px solid rgba(144,124,255,.35);background:linear-gradient(135deg,rgba(144,124,255,.10),rgba(85,214,255,.05))}
.power-alert p{margin:8px 0 0;color:var(--muted)}
.progressive-examples{display:grid;grid-template-columns:repeat(2,1fr);gap:12px;margin:24px 0}
.progressive-examples>.practice-head{grid-column:1/-1}
.progressive-card{padding:18px;border:1px solid var(--line);border-radius:18px;background:var(--panel)}
.progressive-card p{color:var(--muted);font-size:13px}.progressive-card strong{color:var(--green)}
.formula-xl{font-size:20px;margin:11px 0;overflow-x:auto}
.difficulty{display:inline-flex;padding:4px 8px;border-radius:8px;font-size:10px;font-weight:800;letter-spacing:.06em;text-transform:uppercase}
.d1{background:rgba(100,230,179,.12);color:var(--green)}.d2{background:rgba(85,214,255,.12);color:var(--cyan)}.d3{background:rgba(255,182,110,.12);color:var(--orange)}.d4{background:rgba(255,127,143,.12);color:var(--red)}
.download-summary{border-bottom:1px solid var(--line)}
.download-card{display:flex;align-items:center;justify-content:space-between;gap:30px;padding:28px;border:1px solid var(--line);border-radius:26px;background:linear-gradient(135deg,rgba(85,214,255,.09),rgba(144,124,255,.11));box-shadow:var(--shadow)}
.download-card h2{font-size:34px;margin:7px 0}.download-card p{max-width:700px;color:var(--muted);margin:0}.download-actions{display:flex;flex-direction:column;gap:9px;min-width:235px}
.math-fallback{font-family:ui-monospace,SFMono-Regular,Menlo,monospace;white-space:normal}
@media(max-width:820px){.progressive-examples{grid-template-columns:1fr}.download-card{flex-direction:column;align-items:flex-start}.download-actions{width:100%}.download-actions .btn{width:100%}}

/* v5: formule prerenderizzate in SVG, nessuna dipendenza dal motore matematico del browser */
.math-inline{display:inline-block;max-width:100%;vertical-align:middle;color:currentColor;line-height:1.15}
.math-inline svg,.math-display svg{max-width:100%;overflow:visible;color:currentColor}
.math-display{display:block;max-width:100%;margin:.55rem auto;text-align:center;color:currentColor}
.math-large{font-size:1.12em}
.math-xl{font-size:1.22em}
.math-fallback{font-family:"Times New Roman",serif;font-style:italic;white-space:normal}
.formula .math-inline,.training-formula .math-inline,.tutor-formula .math-inline,.sheet-formula .math-inline{font-size:1.08em}
.answer-option .math-inline,.quiz-option .math-inline{font-size:1.02em}
.solution-step .math-inline,.constraint-item .math-inline{margin:0 .08em}

/* v7: hero più leggibile e compilazione LaTeX trasparente */
.formula-card{display:none!important}
.hero-graph-caption{position:absolute;left:7%;right:7%;bottom:5%;padding:14px 16px;border-radius:16px;background:color-mix(in srgb,var(--panel-solid) 90%,transparent);border:1px solid var(--line);display:flex;flex-direction:column;gap:2px;z-index:3}
.hero-graph-caption strong{font-size:14px}.hero-graph-caption span{font-size:11px;color:var(--muted)}
.compile-note{margin-top:12px;padding:12px 14px;border:1px solid rgba(85,214,255,.2);background:rgba(85,214,255,.055);border-radius:12px;color:var(--muted);font-size:11px;line-height:1.45}
.compile-note strong{color:var(--text)}.compile-note code{color:var(--cyan)}