:root{--red:#df252d;--green:#078652;--green2:#0aa069;--ink:#102f27;--muted:#63776f;--line:#c6d9d1;--soft:#f3faf7;--white:#fff;--yellow:#b97800;--shadow:0 16px 45px rgba(8,70,49,.09)}
*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;background:#f8fcfa;color:var(--ink);font-family:Arial,Helvetica,sans-serif}.container{width:min(1180px,calc(100% - 40px));margin:auto}.top{position:sticky;top:0;z-index:30;background:rgba(248,252,250,.96);backdrop-filter:blur(10px);border-bottom:1px solid #dce9e3}.top-inner{min-height:78px;display:flex;align-items:center;gap:25px}.brand{text-decoration:none;font-weight:900;font-size:26px;letter-spacing:-1.5px;white-space:nowrap}.turbo{color:var(--red)}.uroki{color:var(--green)}.nav{margin-left:auto;display:flex;gap:18px;align-items:center;flex-wrap:wrap}.nav a{font:700 13px ui-monospace,monospace;text-decoration:none;color:#5a6e66}.nav a:hover,.nav a.active{color:var(--green)}
.hero{padding:62px 0 46px;background:linear-gradient(125deg,#fbfdfc,#eef8f3);border-bottom:1px solid #dce9e3;position:relative;overflow:hidden}.hero:after{content:'x²  √  π  %  ∆';position:absolute;right:4%;top:25px;font:900 clamp(42px,7vw,96px) ui-monospace,monospace;color:rgba(7,134,82,.06);letter-spacing:8px}.crumbs{display:flex;gap:8px;align-items:center;font:13px ui-monospace,monospace;color:#71827c;margin-bottom:20px}.crumbs a{color:var(--green);text-decoration:none}.badge{display:inline-flex;padding:7px 11px;background:#e7f6ef;border-left:3px solid var(--green);font:700 12px ui-monospace,monospace;color:#3f6b5d;margin-bottom:18px}.hero h1{font-size:clamp(38px,6vw,66px);line-height:1;letter-spacing:-2.8px;margin:0 0 16px;max-width:900px}.hero h1 span{color:var(--green)}.hero p{max-width:820px;color:#576d65;font-size:18px;line-height:1.6;margin:0}.stats{display:flex;gap:10px;flex-wrap:wrap;margin-top:24px}.stat{background:#fff;border:1px solid var(--line);padding:10px 13px;font:700 12px ui-monospace,monospace}.stat b{color:var(--green)}
.main{padding:38px 0 74px}.toolbar{display:flex;gap:12px;flex-wrap:wrap;align-items:center;margin-bottom:22px}.search{flex:1;min-width:230px;padding:13px 15px;border:1px solid var(--line);background:white;font-size:15px;outline:none}.search:focus{border-color:var(--green)}.filter{padding:11px 13px;border:1px solid var(--line);background:#fff;cursor:pointer;font-weight:800;color:#53675f}.filter.active{background:var(--green);color:white;border-color:var(--green)}.progress-card{border:1px solid var(--line);background:#fff;padding:17px;margin-bottom:24px;display:flex;gap:20px;align-items:center}.progress-line{height:8px;background:#e9f0ed;flex:1;overflow:hidden}.progress-line i{display:block;height:100%;background:var(--green);width:0}.progress-text{font:800 12px ui-monospace,monospace;white-space:nowrap}.notice{border-left:4px solid var(--red);background:#fff6f6;padding:15px 17px;margin:0 0 24px;color:#684d4f;line-height:1.55}.grid{display:grid;grid-template-columns:repeat(3,1fr);gap:16px}.lesson-card{background:#fff;border:1px solid var(--line);padding:20px;text-decoration:none;color:inherit;min-height:185px;display:flex;flex-direction:column;transition:.18s}.lesson-card:hover{transform:translateY(-3px);border-color:var(--green);box-shadow:var(--shadow)}.card-top{display:flex;justify-content:space-between;gap:12px}.num{font:900 13px ui-monospace,monospace;color:var(--green)}.level{font:800 10px ui-monospace,monospace;text-transform:uppercase;padding:4px 7px;background:#edf7f2;color:#4b7164}.level.high{background:#fff1f1;color:#9b3d42}.level.advanced{background:#fff8e9;color:#8a660e}.lesson-card h2{font-size:21px;line-height:1.15;margin:18px 0 8px;letter-spacing:-.5px}.lesson-card p{color:#6a7c75;line-height:1.45;font-size:14px;margin:0 0 18px}.card-foot{margin-top:auto;display:flex;justify-content:space-between;font:800 11px ui-monospace,monospace;color:#6f8079}.done .card-foot{color:var(--green)}
.lesson-wrap{display:grid;grid-template-columns:minmax(0,1fr) 280px;gap:24px;padding:34px 0 72px}.article{min-width:0}.lesson-head{background:#fff;border:1px solid var(--line);padding:28px;margin-bottom:18px}.lesson-kicker{font:800 12px ui-monospace,monospace;color:var(--green);margin-bottom:10px}.lesson-head h1{font-size:clamp(30px,5vw,48px);letter-spacing:-1.8px;line-height:1.04;margin:0 0 12px}.lesson-head p{font-size:17px;line-height:1.6;color:#5e7169;margin:0}.block{background:#fff;border:1px solid var(--line);padding:24px;margin:0 0 16px}.block h2{font-size:25px;letter-spacing:-.7px;margin:0 0 14px}.block h3{font-size:18px;margin:20px 0 9px}.block p,.block li{line-height:1.65;color:#435c53}.formula{font:800 15px ui-monospace,monospace;background:#eff8f4;border-left:3px solid var(--green);padding:12px 14px;margin:10px 0}.steps{counter-reset:s}.steps li{list-style:none;position:relative;padding-left:39px;margin:12px 0}.steps li:before{counter-increment:s;content:counter(s);position:absolute;left:0;top:1px;width:25px;height:25px;border-radius:50%;background:var(--green);color:#fff;display:grid;place-items:center;font:800 11px ui-monospace,monospace}.example{background:#f7fbf9;border:1px dashed #a9c7ba;padding:15px;line-height:1.6}.practice{border:2px solid #b8d8ca}.practice label{display:block;font-weight:800;margin:12px 0 8px}.answer{width:100%;padding:13px 14px;border:1px solid var(--line);font-size:16px;outline:none}.answer:focus{border-color:var(--green)}.btn{border:0;padding:12px 16px;background:var(--green);color:#fff;font-weight:900;cursor:pointer;margin-top:10px}.btn.secondary{background:#eef6f2;color:var(--green);border:1px solid var(--line)}.feedback{margin-top:11px;min-height:22px;font-weight:800}.feedback.ok{color:var(--green)}.feedback.bad{color:var(--red)}.checklist{padding-left:20px}.side{position:sticky;top:100px;height:max-content}.sidebox{background:#fff;border:1px solid var(--line);padding:18px;margin-bottom:14px}.sidebox h3{margin:0 0 11px;font-size:16px}.sidebox a{display:block;text-decoration:none;color:#536b62;padding:7px 0;font-size:13px}.sidebox a:hover{color:var(--green)}.mark{width:100%;padding:12px;border:1px solid var(--green);background:#fff;color:var(--green);font-weight:900;cursor:pointer}.mark.done{background:var(--green);color:#fff}.navlessons{display:flex;justify-content:space-between;gap:12px;margin-top:17px}.navlessons a{flex:1;border:1px solid var(--line);padding:13px;text-decoration:none;color:var(--green);font-weight:800}.navlessons a:last-child{text-align:right}.footer{border-top:1px solid #dce9e3;padding:28px 0 44px;color:#6a7a74}.footer-inner{display:flex;justify-content:space-between;gap:20px;align-items:center}
@media(max-width:900px){.grid{grid-template-columns:repeat(2,1fr)}.lesson-wrap{grid-template-columns:1fr}.side{position:static}.top-inner{align-items:flex-start;flex-direction:column;padding:16px 0;gap:12px}.nav{margin-left:0}}
@media(max-width:580px){.container{width:min(100% - 24px,1180px)}.grid{grid-template-columns:1fr}.hero{padding:43px 0 34px}.hero h1{font-size:40px}.progress-card{align-items:flex-start;flex-direction:column}.progress-line{width:100%;flex:auto}.nav{gap:11px}.lesson-head,.block{padding:18px}.navlessons{flex-direction:column}.navlessons a:last-child{text-align:left}}