:root{--blue:#245f94;--blue-light:#eaf3fb;--dark:#1b3045;--muted:#647587;--line:#d9e4ee;--bg:#f4f7fa;--ok:#24754c;--error:#b34242}*{box-sizing:border-box}body{font-family:system-ui,-apple-system,"Segoe UI",sans-serif;background:var(--bg);color:var(--dark);margin:0;line-height:1.52}.wrap{max-width:1060px;margin:auto;padding:28px 20px 65px}.eyebrow{font-size:12px;letter-spacing:.12em;font-weight:800;color:var(--blue);margin-bottom:12px}.eyebrow span{color:#a2b0bb;padding:0 5px}.intro{display:flex;align-items:center;justify-content:space-between;gap:25px;margin-bottom:22px}.intro h1{font-size:clamp(26px,3.4vw,36px);letter-spacing:-.035em;margin:0 0 10px}.intro p{max-width:670px;margin:0;color:var(--muted)}.eva-mini{border:1px solid var(--line);border-radius:13px;background:#fff;padding:14px;display:flex;align-items:center;gap:7px;white-space:nowrap;color:var(--blue);font-size:12px}.eva-mini b{background:var(--blue-light);padding:6px 7px;border-radius:6px}.steps{display:flex;align-items:center;gap:8px;flex-wrap:wrap;margin-bottom:18px}.step{border:0;background:transparent;color:var(--muted);display:flex;align-items:center;gap:7px;padding:5px;font:inherit;font-size:13px;cursor:pointer}.step span{display:grid;place-items:center;height:28px;width:28px;border:1px solid #bccbd8;border-radius:50%;background:white;font-weight:750}.step.active{color:var(--blue);font-weight:750}.step.active span,.step.completed span{background:var(--blue);color:#fff;border-color:var(--blue)}.step:disabled{opacity:.45;cursor:not-allowed}.step-connector{height:1px;width:12px;background:var(--line)}.exercise{background:#fff;border-radius:16px;border:1px solid var(--line);padding:26px;box-shadow:0 5px 22px #263f5a0b;min-height:480px}.section-head{display:flex;justify-content:space-between;align-items:start;gap:15px}.section-head h2{font-size:23px;margin:0 0 7px}.subtitle{color:var(--muted);margin:0 0 20px}.progress{font-size:13px;font-weight:700;background:var(--blue-light);color:var(--blue);padding:7px 12px;border-radius:20px;white-space:nowrap}.grid{display:grid;grid-template-columns:1fr 1fr;gap:16px;align-items:start}.visual{border:1px solid var(--line);border-radius:12px;background:#f9fcff;padding:12px;text-align:center}.visual img{max-height:285px;width:100%;object-fit:contain}.circle-svg{max-width:100%;height:auto;display:block;margin:auto}.panel{border:1px solid var(--line);background:#f9fbfd;border-radius:12px;padding:18px}.panel h3,.question h3{margin:0 0 12px;font-size:17px}.panel p{margin:8px 0}.question{border:1px solid var(--line);border-radius:12px;padding:17px;margin:16px 0}.question>p:first-child{margin-top:0}.choice-list{display:flex;flex-wrap:wrap;gap:9px}.choice{border:1px solid #a5c6df;background:#eef6fc;color:#184c74;border-radius:9px;padding:10px 13px;font:inherit;font-weight:650;cursor:pointer}.choice:hover,.choice:focus-visible{background:#dbeefe}.choice.correct{background:#def3e5;border-color:#62b384;color:#16643a}.choice.wrong{background:#fff0ed;border-color:#da958f;color:#943c32}.choice:disabled{cursor:default}.feedback{margin-top:18px;background:var(--blue-light);color:#24527c;border-radius:10px;padding:12px 14px;font-size:14px;min-height:46px}.feedback.good{background:#e9f7ee;color:var(--ok)}.feedback.wrong{background:#fff3f0;color:var(--error)}.actions{display:flex;justify-content:flex-end;gap:12px;margin-top:18px;flex-wrap:wrap}.btn{border:0;background:var(--blue);color:#fff;border-radius:9px;padding:10px 18px;font:inherit;font-weight:700;cursor:pointer}.btn:disabled{opacity:.4;cursor:not-allowed}.btn.alt{background:#eaf1f7;color:var(--blue)}.btn.small{font-size:13px;padding:8px 12px}.formula{background:#eef5fb;border:1px solid #cee0ef;color:#1b4d75;border-radius:9px;padding:12px;text-align:center;font-size:clamp(20px,2.5vw,27px);font-family:Georgia,serif;margin:12px 0}.formula sub{font-size:.6em}.math-row{font-family:Georgia,serif;font-size:23px;text-align:center;margin:12px}.math-note{font-size:13px;color:var(--muted)}.answer-row{display:flex;align-items:center;flex-wrap:wrap;gap:9px}.answer-row input{flex:1;min-width:100px;max-width:210px;border:1px solid #a7bece;border-radius:8px;padding:11px;font:inherit;font-size:19px}.answer-row input:focus-visible,button:focus-visible{outline:3px solid #9dceee;outline-offset:2px}.tag{display:inline-block;border-radius:6px;background:#e9f2f9;color:#235d88;padding:4px 8px;font-size:12px;font-weight:750}.slider-row{display:flex;gap:12px;align-items:center;margin:14px 0}.slider-row input{width:100%;accent-color:#245f94}.hint{border-left:4px solid #8ab7d7;background:#f4f9fd;border-radius:6px;padding:12px 14px;margin-top:12px}.success{border:1px solid #b7dac2;background:#f2fbf5;border-radius:12px;padding:15px;margin-top:16px}.success h3{color:var(--ok);margin:0 0 5px}.success p{margin:0}.foot{display:flex;align-items:center;justify-content:space-between;gap:12px;color:var(--muted);font-size:12px;margin-top:16px}.restart{border:0;background:transparent;color:var(--blue);cursor:pointer;font:inherit;font-weight:700}.calculator{border:1px solid var(--line);border-radius:10px;padding:12px;max-width:330px;margin:12px auto;background:#f7fafc}.calc-screen{width:100%;border:1px solid #9eb4c4;border-radius:7px;background:white;padding:10px;font:inherit;font-size:18px;text-align:right}.calc-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:6px;margin-top:8px}.calc-grid button{padding:9px 3px;border:1px solid #bfd2e0;background:white;border-radius:6px;font:inherit;cursor:pointer}.calc-grid button:hover{background:#eaf3fb}.mini{font-size:13px;color:var(--muted)}.subtasks{display:grid;gap:12px}.checklist{display:grid;gap:9px}.checklist label{border:1px solid var(--line);border-radius:9px;padding:10px;display:flex;gap:8px;cursor:pointer}.stack{display:grid;gap:12px}.fractions{display:flex;gap:10px;flex-wrap:wrap}.frac{display:inline-flex;flex-direction:column;align-items:center;vertical-align:middle;line-height:1.1}.frac span:first-child{border-bottom:1px solid;padding:0 6px 3px}.frac span:last-child{padding-top:2px}.worked{font-size:18px;font-family:Georgia,serif;line-height:2.1}.pill{color:#256f48;background:#e5f6eb;padding:2px 6px;border-radius:4px}.question-num{font-size:12px;color:var(--blue);font-weight:800;letter-spacing:.05em;text-transform:uppercase}.meter{height:8px;border-radius:999px;background:#e4ecf3;overflow:hidden;margin:0 0 19px}.meter div{height:100%;background:#4f9f70;transition:width .2s}.label-svg{font-size:15px;fill:#1b3045;font-family:system-ui,sans-serif}.blue-svg{fill:#187fc2}.orange-svg{fill:#cf7e12}@media(max-width:850px){.intro{display:block}.eva-mini{display:inline-flex;margin-top:14px}.grid{grid-template-columns:1fr}.step-connector{display:none}}@media(max-width:600px){.wrap{padding:20px 11px 48px}.exercise{padding:16px}.section-head{display:block}.progress{display:inline-block;margin:0 0 12px}.step{font-size:11px}.step span{height:25px;width:25px}.foot{align-items:start;flex-direction:column}.choice{padding:9px}.formula{font-size:21px}}

/* Kompakte Ansicht pro Lernschritt */
.wrap{max-width:800px;padding:12px 14px 24px}.intro{margin-bottom:12px}.intro h1{font-size:clamp(21px,3vw,27px);margin-bottom:4px}.intro p{font-size:13px;line-height:1.45}.eva-mini{display:none}.eyebrow{font-size:10px;margin-bottom:5px}.steps{gap:3px;margin-bottom:10px}.step{font-size:11px;padding:3px;gap:4px}.step span{height:23px;width:23px}.step-connector{width:5px}.exercise{padding:15px;min-height:0;border-radius:12px}.section-head h2{font-size:19px;margin:0 0 3px}.subtitle{font-size:13px;margin-bottom:8px}.meter{margin-bottom:9px}.progress{font-size:11px;padding:4px 9px}.grid{grid-template-columns:minmax(0,1fr) minmax(0,1fr);gap:11px}.visual{padding:6px}.visual img{max-height:210px}.circle-svg{max-height:200px}.panel{padding:12px}.panel h3,.question h3{font-size:16px}.panel p{font-size:14px}.question{margin:9px 0;padding:14px}.feedback{margin-top:10px;padding:9px 12px;min-height:0}.actions{margin-top:10px}.foot{margin-top:10px}.page-label{color:#245f94;font-weight:750;font-size:12px;margin-bottom:9px}.success{margin-top:10px}.steps{overflow-x:auto;flex-wrap:nowrap;padding-bottom:5px}.step{white-space:nowrap}[hidden]{display:none!important}@media(max-width:640px){.wrap{padding:9px 9px 20px}.grid{grid-template-columns:1fr}.intro p{font-size:12px}.step{font-size:10px}.exercise{padding:12px}.visual img{max-height:200px}}

.task-layout{display:grid;grid-template-columns:minmax(220px,320px) minmax(0,1fr);gap:14px;align-items:start}.task-layout .task-content{min-width:0}.helper-visual{position:sticky;top:8px}.helper-visual .circle-svg{max-height:240px}.helper-visual .mini{margin:6px 0 0}.task-content .question{margin:0;padding:0;border:0;background:transparent}.task-content .question-num{margin-bottom:6px}@media(max-width:700px){.task-layout{grid-template-columns:1fr}.helper-visual{position:static}}

html,body{overflow-x:hidden;scrollbar-width:none;-ms-overflow-style:none}body::-webkit-scrollbar,html::-webkit-scrollbar,.wrap::-webkit-scrollbar,.exercise::-webkit-scrollbar,.steps::-webkit-scrollbar{display:none}.steps{scrollbar-width:none;-ms-overflow-style:none}.exercise{overflow:visible}.wrap{overflow-x:hidden}

/* Feinschliff V4: keine sichtbaren Scrollbars, bessere Abstände, keine Überlagerungen */
html,body,.wrap,.exercise{overflow-x:hidden!important;}
html,body,.wrap,.exercise,.steps{scrollbar-width:none!important;-ms-overflow-style:none!important;}
html::-webkit-scrollbar,body::-webkit-scrollbar,.wrap::-webkit-scrollbar,.exercise::-webkit-scrollbar,.steps::-webkit-scrollbar{display:none!important;width:0!important;height:0!important;}
.steps{overflow:visible!important;flex-wrap:wrap!important;row-gap:8px!important;padding-bottom:0!important;}
.step{white-space:normal!important;align-items:center;}
.step-connector{display:none!important;}
.choice-list{display:grid!important;grid-template-columns:repeat(auto-fit,minmax(140px,1fr));gap:10px!important;align-items:stretch;}
.choice{width:100%;min-height:46px;text-align:center;display:flex;align-items:center;justify-content:center;line-height:1.25;white-space:normal;word-break:normal;}
.task-layout{gap:18px!important;grid-template-columns:minmax(240px,320px) minmax(0,1fr)!important;}
.helper-visual{position:static!important;}
.task-content .question h3{line-height:1.3;margin-bottom:14px;}
.feedback,.success{margin-top:14px!important;}
.actions{display:flex;justify-content:flex-end;align-items:center;gap:12px;flex-wrap:wrap;margin-top:16px!important;}
.actions .btn{min-width:140px;}
.foot{display:flex;flex-wrap:wrap;gap:12px 18px;align-items:center;}
.panel,.question,.visual{overflow:hidden;}
@media(max-width:760px){
  .task-layout{grid-template-columns:1fr!important;}
  .choice-list{grid-template-columns:1fr!important;}
  .actions{justify-content:stretch!important;}
  .actions .btn{width:100%;min-width:0;}
  .foot{flex-direction:column;align-items:stretch;}
}

/* V4.1: deutlicher Abstand zwischen Antwortoptionen und Tipp-Schaltfläche */
.question .hint-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  margin-top: 20px;
  margin-bottom: 2px;
}


/* Herleitung Umfangsformel */
.transform-card{display:grid;gap:12px;margin:14px 0 16px}
.transform-row{display:grid;grid-template-columns:minmax(0,1fr) auto minmax(0,1fr);gap:12px;align-items:center}
.equation{background:#eef4fa;border:1px solid #c6d6e6;border-radius:12px;padding:16px 18px;text-align:center;font-size:2rem;font-weight:700;color:#214d7a;line-height:1.2;min-height:78px;display:flex;align-items:center;justify-content:center;flex-wrap:wrap}
.equation.result{background:#f5f9fd}
.operation-hint{background:#fff7e8;border:1px solid #efd3a4;border-radius:12px;padding:10px 14px;font-weight:700;color:#8a5a11;text-align:center;white-space:nowrap}
.frac{display:inline-flex;flex-direction:column;align-items:center;line-height:1;vertical-align:middle;min-width:1.2em}
.frac .top,.frac .bottom{display:block;padding:0 .22em}
.frac .bar{display:block;width:100%;border-top:3px solid currentColor;margin:.12em 0 .14em}
.formula-step h3{margin-bottom:8px}
@media(max-width:760px){
  .transform-row{grid-template-columns:1fr;}
  .operation-hint{justify-self:center}
  .equation{font-size:1.6rem;min-height:64px}
}

/* Interaktive Formelherleitung: stets nur ein Umformungsschritt pro Ansicht */
.formula-intro{margin-bottom:14px}.formula-intro p{margin-bottom:0}
.formula-interactive{display:grid;grid-template-columns:minmax(0,1fr) minmax(210px,0.9fr);gap:12px;align-items:center;margin:14px 0}
.formula-expression{display:flex;gap:8px;align-items:center;justify-content:center;min-height:105px;border:1px solid #c6d9eb;background:#edf5fb;border-radius:12px;font:700 clamp(26px,4vw,36px) Georgia,serif;color:#194e79;padding:16px}
.formula-fraction{display:inline-flex;flex-direction:column;align-items:stretch;line-height:1.05;text-align:center;min-width:1.15em}
.formula-fraction span:first-child{border-bottom:3px solid currentColor;padding:0 5px 5px}
.formula-fraction span:last-child{padding:5px 5px 0}
.formula-operation{border:1px solid #e7d2ad;background:#fffaf1;border-radius:12px;padding:16px;min-width:0}
.formula-operation label{display:block;margin-bottom:9px;font-weight:700;color:#825513}
.formula-input-row{display:flex;gap:8px;align-items:center;flex-wrap:wrap}
.formula-input-row>span{font-size:20px;font-weight:700;color:#825513;white-space:nowrap}
.formula-input-row input{min-width:90px;width:110px;flex:1 1 110px;max-width:100%;font:inherit;padding:9px 10px;border:1px solid #b8cadb;border-radius:8px}
.formula-input-row .btn{flex:0 0 auto}
.formula-reveal{background:#edf8f0;border:1px solid #a6d3b3;border-radius:12px;padding:15px;margin:12px 0 16px;display:flex;gap:10px;align-items:center;justify-content:space-between;flex-wrap:wrap;color:#1f6943}
.formula-reveal strong{font:700 clamp(22px,3vw,31px) Georgia,serif}
.formula-reveal-label{font-weight:700}
.formula-tip{margin:12px 0 6px}.formula-tip .hint{margin-top:12px}
@media(max-width:660px){.formula-interactive{grid-template-columns:1fr}.formula-expression{min-height:82px}}

/* Erste Formelherleitung: nummerierte Gleichungen und Antwortauswahl */
.formula-line-num{display:inline-flex;align-items:center;justify-content:center;background:#dceaf7;color:#195480;border-radius:50%;min-width:30px;height:30px;font:700 16px system-ui,sans-serif;margin-right:12px;flex-shrink:0}
.formula-expression{gap:6px;flex-wrap:wrap}
.formula-intermediate{display:flex;align-items:center;justify-content:center;background:#edf5fb;border:1px solid #c6d9eb;color:#194e79;border-radius:12px;padding:14px;margin:0 0 12px;font:700 clamp(23px,3.4vw,31px) Georgia,serif}
.formula-operation-choices{display:grid;grid-template-columns:1fr;gap:9px;margin-top:12px}
.formula-operation-choices .btn{white-space:normal;min-width:0;width:100%;text-align:center;line-height:1.3}
.formula-stage-label{font-weight:750;color:#825513}
.formula-reveal{justify-content:flex-start}
.formula-reveal strong{margin-left:auto}
@media(max-width:660px){.formula-reveal strong{margin-left:0}.formula-intermediate{font-size:24px}}