:root{
  --ink:#17181b;
  --muted:#676b74;
  --line:#e3e4e8;
  --paper:#f7f6f2;
  --white:#fff;
  --blue:#315fd6;
  --blue-dark:#2348ab;
  --green:#1f9365;
  --red:#b95b5b;
  --font:-apple-system,BlinkMacSystemFont,"SF Pro Display","SF Pro Text","Segoe UI",Helvetica,Arial,sans-serif;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}
body{margin:0;background:var(--paper);color:var(--ink);font-family:var(--font);-webkit-font-smoothing:antialiased}
a{color:inherit;text-decoration:none}
button{font:inherit}
:focus-visible{outline:3px solid rgba(49,95,214,.4);outline-offset:4px}
.skip-link{position:fixed;left:16px;top:-60px;z-index:100;background:var(--ink);color:#fff;padding:10px 14px;border-radius:9px}
.skip-link:focus{top:12px}

.site-header{position:fixed;inset:0 0 auto;height:60px;z-index:50;background:rgba(247,246,242,.82);backdrop-filter:saturate(180%) blur(20px);border-bottom:1px solid rgba(23,24,27,.06)}
.nav{height:100%;max-width:1180px;margin:0 auto;padding:0 28px;display:grid;grid-template-columns:1fr auto 1fr;align-items:center;gap:28px}
.brand{font-size:15px;font-weight:700;letter-spacing:-.02em}
.nav-links{display:flex;gap:30px;font-size:13px;font-weight:500;color:var(--muted)}
.nav-links a{transition:color .18s}
.nav-links a:hover,.nav-links a[aria-current="page"]{color:var(--ink)}
.nav-links a[aria-current="page"]{font-weight:700}
.nav-cta{justify-self:end;color:var(--blue);font-size:12.5px;font-weight:650}

.page-hero{padding:150px 28px 92px;overflow:hidden}
.page-wrap{max-width:1080px;margin:0 auto}
.back-link{display:inline-flex;align-items:center;gap:8px;color:#7c8088;font-size:13px;margin-bottom:38px}
.back-link:hover{color:var(--ink)}
.hero-grid{display:grid;grid-template-columns:.82fr 1.18fr;gap:70px;align-items:center}
h1{font-size:clamp(48px,6.3vw,78px);line-height:.98;letter-spacing:-.052em;margin:0;font-weight:680}
.hero-lead{font-size:19px;line-height:1.62;color:var(--muted);max-width:530px;margin:25px 0 0}
.hero-demo{position:relative;min-height:430px;display:grid;place-items:center}
.hero-demo::before{content:"";position:absolute;width:530px;height:410px;border-radius:50%;background:radial-gradient(circle,rgba(49,95,214,.11),rgba(31,147,101,.04) 45%,transparent 72%);filter:blur(8px)}

.page-section{padding:96px 28px}
.section-heading{max-width:740px;margin:0 auto 58px;text-align:center}
h2{font-size:clamp(35px,4.3vw,55px);line-height:1.04;letter-spacing:-.043em;margin:0;font-weight:680}
.section-heading p{font-size:18px;line-height:1.6;color:var(--muted);max-width:660px;margin:19px auto 0}
.feature-list{max-width:1080px;margin:0 auto}
.feature-row{display:grid;grid-template-columns:.72fr 1.28fr;gap:72px;align-items:center;padding:72px 0}
.feature-row.reverse{grid-template-columns:1.28fr .72fr}
.feature-row.reverse .feature-copy{order:2}
.feature-copy h3{font-size:31px;line-height:1.08;letter-spacing:-.035em;margin:0 0 15px}
.feature-copy p{font-size:16px;line-height:1.65;color:var(--muted);margin:0}
.feature-copy ul{list-style:none;padding:0;margin:23px 0 0;color:#555961;font-size:13.5px}
.feature-copy li{margin:10px 0;display:flex;gap:9px}
.feature-copy li::before{content:"✓";color:var(--green);font-weight:800}
.surface{position:relative;min-height:340px;display:grid;place-items:center}

.workspace{position:relative;width:min(610px,100%);height:380px;background:#fff;border:1px solid #dfe1e6;border-radius:16px;box-shadow:0 28px 70px rgba(22,26,35,.11);overflow:hidden;display:grid;grid-template-columns:145px 1fr}
.workspace-side{background:#eff1f4;border-right:1px solid #e0e2e6;padding:23px 16px}
.workspace-brand{font-size:11px;font-weight:750;margin-bottom:26px}
.workspace-nav{font-size:10px;color:#777b83;padding:9px 10px;margin:4px 0;border-radius:6px}
.workspace-nav.active{background:#25272c;color:#fff}
.workspace-editor{padding:25px 28px;position:relative}
.editor-title{font-size:17px;font-weight:750}
.editor-path{font-size:9px;color:#969aa2;margin-top:5px}
.editor-line{height:5px;border-radius:5px;background:#e5e7ea;margin:9px 0}
.editor-line:nth-of-type(1){width:87%;margin-top:24px}.editor-line:nth-of-type(2){width:72%}.editor-line:nth-of-type(3){width:91%}
.box-demo{position:absolute;left:27px;right:27px;border-radius:10px;padding:16px 18px}
.box-demo.math{top:150px;background:#eef3ff;border-left:3px solid var(--blue)}
.box-demo.math strong{display:block;font:600 20px Georgia,serif}
.box-demo.math span{display:block;font-size:9px;color:#75809b;margin-top:7px}
.box-demo.source{bottom:24px;background:#f3f4f6}
.box-demo.source strong{display:block;font-size:11px}.box-demo.source span{font-size:9px;color:#777b83}

.math-surface{width:min(540px,100%);padding:32px 34px;background:#fff;border-radius:15px;box-shadow:0 22px 54px rgba(22,26,35,.09)}
.math-toolbar{display:flex;gap:9px;margin-bottom:25px}
.math-toolbar span{font-size:10px;padding:8px 10px;border-radius:7px;background:#eef0f3;color:#6d7179}
.math-equation{padding:31px;background:#f1f4fb;border-left:3px solid var(--blue);font:600 27px Georgia,serif;text-align:center}
.math-caption{font-size:11px;color:#8e929a;margin-top:14px}

.sketch-surface{position:relative;width:min(540px,100%);height:330px;background-color:#fff;background-image:linear-gradient(#edf0f3 1px,transparent 1px),linear-gradient(90deg,#edf0f3 1px,transparent 1px);background-size:22px 22px;border-radius:15px;box-shadow:0 22px 54px rgba(22,26,35,.09);overflow:hidden}
.sketch-node{position:absolute;padding:11px 15px;border-radius:10px;background:#fff;border:1px solid #dfe2e7;font-size:12px;font-weight:650;box-shadow:0 9px 20px rgba(22,26,35,.07);z-index:2}
.sketch-node.main{left:42%;top:42%;background:#25272c;color:#fff;border-color:#25272c}
.sketch-node.a{left:8%;top:18%}.sketch-node.b{right:8%;top:14%}.sketch-node.c{right:9%;bottom:14%}.sketch-node.d{left:10%;bottom:16%}
.sketch-line{position:absolute;height:2px;background:#bfc5cf;left:49%;top:49%;width:40%;transform-origin:left center}
.sketch-line.a{transform:rotate(210deg)}.sketch-line.b{transform:rotate(-38deg)}.sketch-line.c{transform:rotate(36deg)}.sketch-line.d{transform:rotate(145deg)}

.sources{width:min(550px,100%);background:#fff;border-radius:15px;box-shadow:0 22px 54px rgba(22,26,35,.09);padding:24px}
.source-title{font-size:13px;font-weight:750;margin-bottom:17px}
.source-row{display:grid;grid-template-columns:76px 1fr auto;gap:13px;align-items:center;padding:15px 0;border-top:1px solid #eceef1}
.source-type{font-size:9px;color:#315fd6;font-weight:750}.source-name{font-size:11px;font-weight:650}.source-meta{font-size:9px;color:#90949c}

.learning-shell{width:min(620px,100%);position:relative}
.flashcard{position:relative;height:280px;border:0;background:transparent;width:100%;padding:0;perspective:1000px;cursor:pointer}
.flashcard-inner{position:absolute;inset:0;transition:transform .55s;transform-style:preserve-3d}
.flashcard.flipped .flashcard-inner{transform:rotateY(180deg)}
.flash-face{position:absolute;inset:0;backface-visibility:hidden;background:#fff;border:1px solid #dfe1e6;border-radius:17px;box-shadow:0 24px 58px rgba(22,26,35,.1);display:flex;align-items:center;justify-content:center;text-align:center;padding:38px}
.flash-face.back{transform:rotateY(180deg)}
.flash-label{position:absolute;left:22px;top:19px;font-size:9px;letter-spacing:.12em;color:#979ba3;font-weight:750}
.flash-face strong{font-size:21px}.flash-face p{font-size:15px;line-height:1.6;color:#44474d;margin:0}
.review-row{display:grid;grid-template-columns:repeat(4,1fr);gap:8px;margin-top:13px}
.review{border:0;border-radius:9px;background:#e7e9ed;color:#555961;padding:11px 4px;cursor:pointer;font-size:10px;transition:background .18s,color .18s,transform .18s}
.review:hover,.review.active{background:#25272c;color:#fff;transform:translateY(-2px)}
.learning-stats{display:grid;grid-template-columns:repeat(3,1fr);gap:10px;margin-top:22px}
.stat{padding:15px 4px;text-align:center}
.stat strong{display:block;font-size:20px}.stat span{display:block;color:#92969e;font-size:9.5px;margin-top:5px}
.analytics-shell{width:min(580px,100%);background:#fff;border-radius:16px;box-shadow:0 22px 54px rgba(22,26,35,.09);padding:27px}
.analytics-head{display:flex;justify-content:space-between;align-items:center;margin-bottom:24px}
.analytics-head strong{font-size:14px}.analytics-head span{font-size:10px;color:#8c9098}
.analytics-metrics{display:grid;grid-template-columns:repeat(3,1fr);gap:8px;margin-bottom:26px}
.analytics-metric{background:#f5f6f8;border-radius:10px;padding:14px}
.analytics-metric strong{display:block;font-size:19px}.analytics-metric span{display:block;font-size:9px;color:#8d9199;margin-top:5px}
.bar-chart{height:135px;display:flex;align-items:end;gap:10px;padding:0 4px 23px;border-bottom:1px solid #e4e6ea}
.bar-chart i{height:calc(var(--h)*1%);background:#cbd6f3;border-radius:5px 5px 2px 2px;flex:1;position:relative}
.bar-chart i.active{background:var(--blue)}
.bar-chart i::after{content:attr(data-day);position:absolute;top:calc(100% + 8px);left:50%;transform:translateX(-50%);font-style:normal;font-size:8px;color:#989ca4}

.instrument-tabs{display:flex;justify-content:center;gap:30px;flex-wrap:wrap;margin:0 0 52px;border-bottom:1px solid #d7d9df}
.instrument-tab{border:0;border-bottom:2px solid transparent;background:transparent;color:#747881;padding:13px 1px 12px;cursor:pointer;font-size:13px;font-weight:650}
.instrument-tab[aria-selected="true"]{border-bottom-color:var(--ink);color:var(--ink)}
.instrument-panel{display:grid;grid-template-columns:.7fr 1.3fr;gap:65px;align-items:center;min-height:480px}
.instrument-panel[hidden]{display:none}
.instrument-copy h3{font-size:33px;line-height:1.08;letter-spacing:-.035em;margin:0 0 15px}
.instrument-copy p{font-size:16px;line-height:1.65;color:var(--muted);margin:0}
.instrument-copy .hint{font-size:12px;color:#92969e;margin-top:18px}

.quiz-shell{width:min(560px,100%);background:#fff;border-radius:16px;box-shadow:0 22px 54px rgba(22,26,35,.09);padding:27px}
.quiz-head{display:flex;justify-content:space-between;align-items:center;font-size:10px;color:#8b8f97;margin-bottom:20px}
.quiz-question{font-size:17px;font-weight:750;margin-bottom:18px}
.answer{display:flex;width:100%;align-items:center;gap:11px;padding:13px 14px;margin:8px 0;background:#f7f8fa;border:1px solid #e0e2e7;border-radius:10px;color:#36393f;text-align:left;cursor:pointer}
.answer::before{content:"";width:17px;height:17px;border:2px solid #c8cbd2;border-radius:50%;flex:none}
.answer.correct{background:#eaf7f0;border-color:#63b68a}.answer.correct::before{border-color:var(--green);background:var(--green);box-shadow:inset 0 0 0 4px #eaf7f0}
.answer.wrong{background:#fff0f0;border-color:#df9191}
.quiz-result{min-height:20px;font-size:11px;color:#777b83;margin-top:14px}

.podcast-shell{width:min(560px,100%);background:#fff;border-radius:16px;box-shadow:0 22px 54px rgba(22,26,35,.09);padding:28px}
.podcast-top{display:flex;align-items:center;gap:17px}
.play{width:52px;height:52px;border-radius:50%;border:0;background:#25272c;color:#fff;font-size:17px}
.wave{height:50px;display:flex;align-items:center;gap:4px;flex:1}
.wave i{width:4px;height:calc(var(--h)*1%);min-height:5px;border-radius:4px;background:#bdc7df}
.podcast-shell.playing .wave i{animation:wavePulse .75s ease-in-out infinite alternate}
.podcast-shell.playing .wave i:nth-child(3n){animation-delay:.14s}.podcast-shell.playing .wave i:nth-child(4n){animation-delay:.28s}
@keyframes wavePulse{to{height:calc((var(--h) + 15)*1%);background:#6f89c8}}
.podcast-shell h4{font-size:15px;margin:21px 0 7px}.podcast-shell p{font-size:12px;line-height:1.55;color:#747881;margin:0}
.transcript{margin-top:18px;padding-top:17px;border-top:1px solid #eceef1;font-size:12px;line-height:1.6;color:#45484e}

.planner-shell{width:min(680px,100%);background:#fff;border-radius:17px;box-shadow:0 26px 64px rgba(22,26,35,.1);padding:25px}
.planner-head{display:flex;align-items:center;justify-content:space-between;margin-bottom:20px}
.planner-head strong{font-size:14px}.reschedule{border:0;background:#25272c;color:#fff;border-radius:9px;padding:10px 13px;font-size:11px;cursor:pointer}
.week{display:grid;grid-template-columns:repeat(5,1fr);gap:8px;min-height:290px}
.day{position:relative;background:#f5f6f8;border-radius:11px;padding:13px 7px;transition:background .3s}
.day b{display:block;text-align:center;color:#858992;font-size:9px}
.event{position:absolute;left:7px;right:7px;padding:9px 7px;border-radius:8px;font-size:9px;line-height:1.3;transition:top .45s,transform .45s,opacity .3s}
.event.blue{top:52px;background:#dfe7fb;color:#2449a7}.event.green{top:112px;background:#ddf1e7;color:#1c704f}.event.dark{top:176px;background:#25272c;color:#fff}
.planner-shell.shifted .day:nth-child(4){background:#fff0f0}.planner-shell.shifted .day:nth-child(5){background:#eff6ff}
.planner-shell.shifted .day:nth-child(4) .event.dark{opacity:.25;transform:scale(.9)}
.planner-shell.shifted .day:nth-child(5)::after{content:"Prüfung verschoben";position:absolute;left:7px;right:7px;top:176px;padding:9px 7px;border-radius:8px;background:#25272c;color:#fff;font-size:9px}
.planner-message{font-size:11px;line-height:1.5;color:#777b83;margin:16px 2px 0}

.plan-features{max-width:1080px;margin:0 auto;display:grid;grid-template-columns:repeat(3,1fr);gap:40px}
.plan-feature{padding:27px 0;border-top:1px solid var(--line)}
.plan-feature h3{font-size:20px;letter-spacing:-.025em;margin:0 0 10px}.plan-feature p{font-size:14px;line-height:1.6;color:var(--muted);margin:0}

.page-cta{background:#101216;color:#eef0f4;padding:86px 28px}
.cta-inner{max-width:1080px;margin:0 auto;display:flex;align-items:end;justify-content:space-between;gap:45px}
.cta-inner h2{max-width:680px}.cta-inner p{font-size:16px;line-height:1.6;color:#aeb3be;max-width:650px;margin:17px 0 0}
.cta-link{flex:none;color:#aec0f3;font-size:14px;font-weight:700}
footer{background:var(--paper)}
.footer-inner{max-width:1080px;margin:0 auto;padding:34px 28px;display:flex;justify-content:space-between;align-items:center;gap:20px}
.footer-brand{font-size:14px;font-weight:700}.footer-links{display:flex;gap:22px;color:var(--muted);font-size:12.5px}.copyright{color:#93969d;font-size:12px}

.js .reveal{opacity:0;transform:translateY(18px);transition:opacity .65s ease,transform .65s ease}
.js .reveal.visible{opacity:1;transform:none}

@media(max-width:850px){
  .nav{grid-template-columns:1fr auto}.nav-links{display:none}
  .page-hero{padding-top:116px}.hero-grid{grid-template-columns:1fr;gap:45px}.hero-demo{min-height:390px}
  .feature-row,.feature-row.reverse{grid-template-columns:1fr;gap:38px}.feature-row.reverse .feature-copy{order:0}
  .instrument-panel{grid-template-columns:1fr;gap:38px}.instrument-copy{text-align:center}
  .cta-inner{align-items:start;flex-direction:column}
}
@media(max-width:560px){
  .site-header{height:56px}.nav{padding:0 18px}.nav-cta{font-size:11.5px}
  .page-hero{padding:96px 18px 64px}.back-link{margin-bottom:28px}h1{font-size:46px}.hero-lead{font-size:17px}
  .hero-demo{min-height:330px}.workspace{height:330px;grid-template-columns:105px 1fr}.workspace-side{padding:18px 10px}.workspace-editor{padding:21px 17px}.box-demo{left:17px;right:17px}
  .page-section{padding:72px 18px}.section-heading{margin-bottom:42px}.section-heading p{font-size:16px}
  .feature-row{padding:48px 0}.feature-copy h3{font-size:28px}
  .instrument-tabs{justify-content:flex-start;flex-wrap:nowrap;overflow-x:auto;gap:22px}.instrument-tab{flex:none}
  .flashcard{height:245px}.review-row{grid-template-columns:1fr 1fr}.learning-stats{gap:4px}.stat strong{font-size:17px}
  .instrument-panel{min-height:590px}.quiz-shell,.podcast-shell,.planner-shell{padding:19px}
  .week{gap:4px}.day{padding:10px 3px}.event{left:3px;right:3px;padding:7px 4px;font-size:7.5px}.planner-shell.shifted .day:nth-child(5)::after{left:3px;right:3px;padding:7px 4px;font-size:7.5px}
  .plan-features{grid-template-columns:1fr;gap:14px}
  .page-cta{padding:70px 18px}.footer-inner{flex-direction:column;text-align:center;padding:30px 18px}.footer-links{flex-wrap:wrap;justify-content:center}
}
@media(prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}.js .reveal{opacity:1;transform:none;transition:none}
  .flashcard-inner,.event,.pillar{transition:none}.podcast-shell.playing .wave i{animation:none}
}