:root{
  --ink:#111426;--muted:#747b96;--line:#e8ebf4;--bg:#fbfcff;
  --violet:#6f5cff;--violet2:#8b6dff;--blue:#4d6fff;--soft:#f3f5ff;
  --green:#42c88a;--orange:#ffb548;--red:#ff6f7d;--shadow:0 18px 50px rgba(34,42,86,.10)
}
*{box-sizing:border-box} html{scroll-behavior:smooth}[hidden]{display:none!important}
body{
  margin:0;font-family:Inter,ui-sans-serif,system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;
  color:var(--ink);
  background:radial-gradient(circle at 90% 12%,rgba(111,92,255,.08),transparent 24rem),
             radial-gradient(circle at 7% 76%,rgba(77,111,255,.08),transparent 20rem),var(--bg)
}
button,input{font:inherit} button:disabled{opacity:.45;cursor:not-allowed;box-shadow:none}a{text-decoration:none;color:inherit}
.shell{max-width:1440px;margin:auto;padding:0 34px}
.nav{
  height:84px;display:flex;align-items:center;justify-content:space-between;position:sticky;top:0;z-index:30;
  background:rgba(251,252,255,.82);backdrop-filter:blur(18px);border-bottom:1px solid rgba(232,235,244,.75)
}
.nav-inner{width:100%;display:flex;align-items:center;justify-content:space-between}
.brand{display:flex;align-items:center;gap:14px;font-weight:900;font-size:29px;letter-spacing:-1.5px}
.mark{width:42px;height:42px;position:relative}.mark i{position:absolute;border-radius:10px;background:linear-gradient(145deg,#7b68ff,#5673ff)}
.mark i:nth-child(1){width:28px;height:28px;left:0;top:0}.mark i:nth-child(2){width:28px;height:28px;right:0;bottom:0;opacity:.72}
.links{display:flex;gap:34px;color:#4f5570;font-size:15px}
.navbtn,.primary,.check{
  border:none;border-radius:16px;background:linear-gradient(135deg,var(--violet),var(--violet2));
  color:white;padding:14px 22px;font-weight:800;box-shadow:0 10px 25px rgba(111,92,255,.22);cursor:pointer
}
.hero{display:grid;grid-template-columns:1.05fr .95fr;gap:56px;align-items:center;min-height:560px;padding:68px 0 34px}
.eyebrow{display:inline-block;padding:8px 13px;border-radius:999px;background:#f0edff;color:#5748df;font-size:14px;font-weight:700;margin-bottom:18px}
h1{font-size:66px;line-height:.98;letter-spacing:-4px;margin:0 0 24px;max-width:760px}h1 span{color:var(--violet)}
.lead{font-size:22px;line-height:1.42;color:#68708f;max-width:720px}
.cta{display:flex;gap:14px;margin:30px 0 20px}.primary{padding:16px 24px;font-size:17px}
.ghost{border:1px solid var(--line);background:white;border-radius:16px;padding:16px 22px;font-weight:800;cursor:pointer;box-shadow:0 6px 20px rgba(34,42,86,.05)}
.micro{display:flex;gap:22px;flex-wrap:wrap;color:#8990aa;font-size:13px}.micro span:before{content:"✓";color:#4f6eff;margin-right:7px;font-weight:900}
.hero-card{background:white;border:1px solid var(--line);border-radius:28px;padding:24px;box-shadow:var(--shadow)}
.profile-head{display:flex;justify-content:space-between;align-items:flex-start;gap:16px}.streak{padding:8px 12px;background:#fff3dd;border-radius:999px;font-weight:800;white-space:nowrap}.muted-note{color:var(--muted);font-size:13px;margin-top:4px}
.skill{margin:16px 0}.skill-row{display:flex;justify-content:space-between;font-size:14px;margin-bottom:7px}
.bar{height:8px;background:#edf0f7;border-radius:999px;overflow:hidden}.bar i{display:block;height:100%;background:linear-gradient(90deg,var(--blue),var(--violet));border-radius:999px;transition:width .45s ease}
.featurebar{margin:16px 0 30px;display:grid;grid-template-columns:repeat(3,1fr);gap:1px;border:1px solid var(--line);border-radius:22px;overflow:hidden;background:var(--line)}
.feature{background:white;padding:22px 26px;display:flex;gap:16px;align-items:center}.icon{width:44px;height:44px;border-radius:14px;background:var(--soft);display:grid;place-items:center;font-size:20px}
.feature strong{display:block;margin-bottom:4px}.feature small{color:var(--muted)}

/* Диагностика */
.diagnostic-section{padding:54px 0 46px;scroll-margin-top:92px}
.section-kicker{font-size:13px;font-weight:900;letter-spacing:.12em;text-transform:uppercase;color:#858ca8;margin-bottom:14px}
.diagnostic-card{background:white;border:1px solid var(--line);border-radius:30px;padding:34px;box-shadow:var(--shadow)}
#diagIntro{display:grid;grid-template-columns:1.05fr .95fr;gap:48px;align-items:center}
.diag-copy h2,.result-head h2{font-size:42px;line-height:1.04;letter-spacing:-2px;margin:0 0 14px}.diag-copy p,.result-head p{font-size:17px;line-height:1.55;color:var(--muted);max-width:720px}
.diag-meta{display:flex;gap:10px;flex-wrap:wrap;margin:24px 0}.diag-meta span{padding:9px 12px;border-radius:999px;background:var(--soft);font-size:13px;font-weight:800;color:#606789}
.diag-preview{background:linear-gradient(180deg,#fafaff,#f5f6ff);border:1px solid var(--line);border-radius:24px;padding:22px}
.preview-node{display:grid;grid-template-columns:38px 1fr;column-gap:10px;align-items:center;padding:13px;border-radius:16px;background:white;border:1px solid var(--line)}
.preview-node span{grid-row:1/3;width:34px;height:34px;display:grid;place-items:center;border-radius:11px;background:#f1f3fb;color:#737a99;font-size:12px;font-weight:900}.preview-node b{font-size:14px}.preview-node small{color:var(--muted);margin-top:2px}.preview-node.ready span{background:#ebe8ff;color:#5b4adb}.preview-line{height:14px;width:2px;background:#dfe3ef;margin:auto}
.quiz-card{max-width:900px;margin:auto}
.diag-top{display:flex;align-items:center;justify-content:space-between;gap:22px;margin-bottom:28px}.diag-progress{width:260px;max-width:45%;height:8px;background:#edf0f7;border-radius:999px;overflow:hidden}.diag-progress i{display:block;height:100%;width:0;background:linear-gradient(90deg,var(--blue),var(--violet));transition:width .3s ease}
.diag-question{font-size:28px;font-weight:900;line-height:1.28;margin:8px 0 12px}.diag-math{font-family:Georgia,serif;font-size:38px;line-height:1.3;margin:18px 0 24px;min-height:12px}
.diag-answers{display:grid;grid-template-columns:1fr 1fr;gap:12px}.diag-choice{border:1px solid var(--line);background:white;border-radius:16px;padding:16px 18px;text-align:left;font-weight:800;cursor:pointer;transition:.18s}.diag-choice:hover{border-color:#c8cfff;background:#fbfbff}.diag-choice.selected{border:2px solid #7564ff;background:#f4f2ff;box-shadow:0 8px 22px rgba(111,92,255,.10)}
.diag-actions{display:flex;justify-content:space-between;gap:12px;margin-top:24px}.diag-note{text-align:center;color:#969cb1;font-size:12px;margin-top:16px}
.result-head{display:flex;justify-content:space-between;align-items:center;gap:28px}.score-orb{width:138px;height:138px;flex:0 0 138px;border-radius:50%;background:conic-gradient(var(--violet) var(--score,0%),#eceffa 0);display:grid;place-items:center;position:relative}.score-orb:after{content:"";position:absolute;inset:10px;border-radius:50%;background:white}.score-orb strong,.score-orb span{position:relative;z-index:2;text-align:center}.score-orb strong{font-size:31px;align-self:end}.score-orb span{font-size:11px;color:var(--muted);align-self:start;margin-top:-26px}
.diag-skill-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:12px;margin:28px 0}.diag-skill-card{border:1px solid var(--line);border-radius:18px;padding:16px}.diag-skill-card .skill-score{font-size:27px;font-weight:900;margin:6px 0}.diag-skill-card small{color:var(--muted)}.status-good{color:#29855d}.status-mid{color:#a06a10}.status-low{color:#b94d5d}
.result-columns{display:grid;grid-template-columns:1fr 1fr;gap:18px}.result-block{border:1px solid var(--line);border-radius:22px;padding:22px;background:#fff}.result-title{font-size:12px;text-transform:uppercase;letter-spacing:.1em;font-weight:900;color:#8c93aa;margin-bottom:12px}.gap-item{display:flex;gap:11px;align-items:flex-start;padding:12px 0;border-bottom:1px solid #eff1f6}.gap-item:last-child{border-bottom:none}.gap-dot{width:9px;height:9px;border-radius:50%;background:var(--orange);margin-top:6px;flex:0 0 9px}.gap-item b{font-size:14px}.gap-item small{display:block;color:var(--muted);margin-top:3px;line-height:1.35}.recommendation{background:linear-gradient(180deg,#fafaff,#f6f7ff)}.recommendation h3{font-size:25px;margin:8px 0}.recommendation p{color:var(--muted);line-height:1.5;margin-bottom:20px}.text-button{display:block;margin:22px auto 0;border:none;background:transparent;color:#6658e9;font-weight:800;cursor:pointer}

.demo-layout{display:grid;grid-template-columns:1.05fr .95fr;gap:28px;padding:18px 0 36px;scroll-margin-top:92px}
.panel{background:white;border:1px solid var(--line);border-radius:24px;padding:24px;box-shadow:0 10px 35px rgba(34,42,86,.05)}
.panel h2{font-size:27px;margin:0 0 6px}.sub{color:var(--muted);margin-bottom:18px}
.lesson-top{display:flex;justify-content:space-between;gap:16px;align-items:center;margin-bottom:16px}
.tag{padding:7px 10px;border-radius:999px;background:var(--soft);font-size:12px;color:#5d63a2;font-weight:800}
.q-meta{color:var(--muted);font-size:13px}.question{font-size:24px;line-height:1.35;font-weight:800;margin:24px 0 16px}
.math{font-family:Georgia,serif;font-size:34px;font-weight:400;margin:18px 0}
.answers{display:grid;gap:10px}.choice{
  border:1px solid var(--line);background:white;border-radius:14px;padding:14px 16px;text-align:left;cursor:pointer;font-weight:750;transition:.2s
}
.choice:hover{border-color:#c8cfff;background:#fbfbff}.choice.selected{border:2px solid #7a6bff;background:#f6f4ff}
.inputrow{display:flex;gap:10px}.inputrow input{flex:1;border:2px solid #bdc7ff;border-radius:12px;padding:13px 14px;outline:none;font-weight:800}
.feedback{margin-top:18px;border-radius:18px;background:#f6f7fb;padding:18px;min-height:104px;color:#555d78}
.feedback.good{background:#ecfbf4;color:#27684e}.feedback.bad{background:#fff0f2;color:#9b4050}
.controls{display:flex;justify-content:space-between;gap:10px;margin-top:18px}.control-group{display:flex;gap:10px}
.smallbtn{border:1px solid var(--line);background:white;border-radius:12px;padding:12px 14px;font-weight:800;cursor:pointer}
.check{border-radius:12px;padding:12px 18px}
.sidebar-title{font-weight:900;margin-bottom:10px}.road-item{display:grid;grid-template-columns:34px 1fr 72px;gap:12px;align-items:center;border:1px solid var(--line);border-radius:16px;padding:13px;margin:10px 0}
.road-icon{width:32px;height:32px;border-radius:10px;background:var(--soft);display:grid;place-items:center}.road-item strong{font-size:14px}.road-item small{display:block;color:var(--muted);margin-top:3px}
.mini-progress{height:6px;background:#edf0f7;border-radius:999px;overflow:hidden}.mini-progress i{display:block;height:100%;background:linear-gradient(90deg,var(--blue),var(--violet));border-radius:999px}
.fact{margin-top:20px;background:linear-gradient(180deg,#fafaff,#f5f6ff);border:1px solid var(--line);border-radius:20px;padding:18px}.fact h3{font-size:18px;margin:8px 0}.fact p{color:var(--muted);font-size:13px;line-height:1.45}
.bottom-grid{display:grid;grid-template-columns:1fr 1fr 1fr;gap:22px;padding:4px 0 80px}
.stat{background:white;border:1px solid var(--line);border-radius:22px;padding:22px}.stat big{display:block;font-size:32px;font-weight:900;margin-top:8px}.stat span{color:var(--muted)}
.footer{padding:26px 0 50px;color:#8990aa;font-size:13px;display:flex;justify-content:space-between}
.toast{position:fixed;left:50%;bottom:28px;transform:translateX(-50%) translateY(30px);opacity:0;background:#15182a;color:#fff;padding:12px 18px;border-radius:14px;transition:.25s;z-index:60;font-weight:700}
.toast.show{transform:translateX(-50%) translateY(0);opacity:1}
@media(max-width:1000px){.hero,.demo-layout,#diagIntro,.result-columns{grid-template-columns:1fr}.diag-skill-grid{grid-template-columns:1fr 1fr}.bottom-grid{grid-template-columns:1fr 1fr}h1{font-size:54px}.diag-preview{max-width:700px}.result-head{align-items:flex-start}}
@media(max-width:760px){.shell{padding:0 18px}.links{display:none}.navbtn{padding:11px 14px;font-size:13px}h1{font-size:44px;letter-spacing:-2.5px}.lead{font-size:18px}.featurebar,.bottom-grid,.diag-skill-grid,.diag-answers{grid-template-columns:1fr}.hero{padding-top:38px}.diagnostic-card{padding:22px}.diag-copy h2,.result-head h2{font-size:34px}.diag-top{align-items:flex-start;flex-direction:column}.diag-progress{max-width:none;width:100%}.diag-question{font-size:23px}.diag-math{font-size:32px}.result-head{flex-direction:column}.score-orb{width:120px;height:120px;flex-basis:120px}.diag-actions,.controls{flex-direction:column}.control-group{display:grid;grid-template-columns:1fr 1fr}.control-group .smallbtn:last-child{grid-column:1/-1}.footer{gap:12px;flex-direction:column}}