:root{--red:#df252d;--green:#078652;--green2:#0aa069;--dark:#102f27;--ink:#234238;--muted:#63776f;--line:#bfd5cb;--soft:#f4faf7;--white:#fff;--yellow:#a06a00;--violet:#7149a4;--shadow:0 18px 55px rgba(8,70,49,.09)}
*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;background:#f9fcfa;color:var(--ink);font-family:Arial,Helvetica,sans-serif}.container{width:min(1180px,calc(100% - 40px));margin:auto}.top{background:rgba(249,252,250,.96);border-bottom:1px solid #dce8e3;position:sticky;top:0;z-index:20}.top-inner{min-height:84px;display:flex;align-items:center;gap:28px}.brand{text-decoration:none;font-family:Arial,Helvetica,sans-serif;font-weight:900;font-size:27px;letter-spacing:-1.5px;white-space:nowrap}.brand .turbo{color:var(--red)}.brand .uroki{color:var(--green)}.nav{display:flex;gap:23px;margin-left:auto;align-items:center;flex-wrap:wrap}.nav a{text-decoration:none;color:#536960;font-weight:700;font-size:14px}.nav a:hover,.nav a.active{color:var(--green)}
.hero,.lesson-hero{position:relative;overflow:hidden;padding:62px 0;border-bottom:1px solid #dce8e3;background:linear-gradient(120deg,#f9fcfa 4%,#edf8f3 62%,#e7f7f0)}.hero:before,.lesson-hero:before{content:"";position:absolute;inset:0;background-image:linear-gradient(rgba(12,111,75,.035) 1px,transparent 1px),linear-gradient(90deg,rgba(12,111,75,.035) 1px,transparent 1px);background-size:32px 32px;pointer-events:none}.hero-grid{position:relative;display:grid;grid-template-columns:minmax(0,1fr) 340px;gap:34px;align-items:start}.crumbs{position:relative;display:flex;gap:8px;align-items:center;color:#71857d;font-size:13px;margin-bottom:22px;flex-wrap:wrap}.crumbs a{color:var(--green);text-decoration:none;font-weight:700}.eyebrow{position:relative;display:inline-flex;padding:8px 12px;border-left:3px solid var(--green);background:#e7f6ee;color:#2b6951;font-size:12px;font-weight:900;letter-spacing:.07em;text-transform:uppercase}.hero h1,.lesson-hero h1{position:relative;color:var(--dark);font-size:clamp(40px,5.5vw,68px);line-height:1.02;letter-spacing:-2.5px;margin:20px 0 18px}.lesson-hero h1{font-size:clamp(34px,4.3vw,56px);max-width:980px}.accent{color:var(--green)}.hero p,.lesson-hero p{position:relative;font-size:18px;line-height:1.65;color:var(--muted);max-width:860px}.hero-stats{display:flex;gap:30px;margin-top:32px;flex-wrap:wrap}.stat strong{display:block;font-size:31px;color:var(--dark)}.stat span{font-size:13px;color:var(--muted)}
.side-card,.content-card,.sidebar-card{background:#fff;border:1px solid var(--line);box-shadow:var(--shadow)}.side-card{padding:25px}.side-card h3,.sidebar-card h3{margin:0 0 10px;color:var(--dark)}.side-card p,.sidebar-card p{color:var(--muted);line-height:1.5}.progress-row{display:flex;justify-content:space-between;gap:14px;margin-top:20px;font-size:13px}.track{height:10px;background:#e6efea;margin-top:9px;overflow:hidden}.track span{display:block;height:100%;width:0;background:linear-gradient(90deg,var(--red),var(--green));transition:.25s}
.section{padding:56px 0 78px}.section-head{display:flex;align-items:flex-end;justify-content:space-between;gap:24px;margin-bottom:24px}.section-head h2{font-size:34px;margin:0 0 8px;color:var(--dark)}.section-head p{margin:0;color:var(--muted)}.source{color:var(--green);font-weight:800;text-decoration:none}.toolbar{display:flex;gap:16px;align-items:center;margin:22px 0 26px;flex-wrap:wrap}.search{flex:1;min-width:260px;padding:14px 16px;border:1px solid #b9d1c5;background:white;font:inherit;outline:none}.search:focus{border-color:var(--green);box-shadow:0 0 0 3px rgba(7,139,91,.08)}.filters{display:flex;gap:8px;flex-wrap:wrap}.filter{border:1px solid #bed4ca;background:#fff;padding:12px 14px;font-weight:800;color:#456057;cursor:pointer}.filter.active,.filter:hover{background:var(--green);border-color:var(--green);color:#fff}.task-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:18px}.task-card{display:block;background:white;border:1px solid var(--line);padding:22px;text-decoration:none;color:inherit;min-height:230px;transition:.18s}.task-card:hover{transform:translateY(-3px);border-color:#8ab8a4;box-shadow:var(--shadow)}.task-num{display:flex;justify-content:space-between;gap:12px;align-items:center}.task-num b{font-size:19px;color:var(--dark)}.badge,.pill{display:inline-flex;padding:6px 9px;font-size:11px;font-weight:900;text-transform:uppercase;letter-spacing:.04em}.badge.base{background:#e8f7ef;color:#17734d}.badge.advanced{background:#fff3d8;color:#8d6513}.badge.high{background:#f2eafa;color:#7042a0}.task-card h3{font-size:19px;line-height:1.24;margin:18px 0 10px;color:var(--dark)}.task-card p{font-size:14px;line-height:1.5;color:var(--muted);margin:0}.task-foot{display:flex;justify-content:space-between;gap:12px;margin-top:22px;padding-top:16px;border-top:1px solid #edf2ef;font-size:12px;color:#648076}.task-foot span:last-child{font-weight:900;color:var(--green)}
.lesson-meta{display:flex;gap:9px;flex-wrap:wrap;margin-top:22px;position:relative}.pill{background:#e9f6f0;color:#23664b;border:1px solid #cce6da}.lesson-layout{display:grid;grid-template-columns:minmax(0,1fr) 300px;gap:28px;align-items:start}.content-card{padding:28px;margin-bottom:18px}.content-card h2{margin:0 0 16px;color:var(--dark);font-size:26px}.content-card p,.content-card li{line-height:1.7}.formula-box,.example{padding:18px 20px;background:#f1f8f4;border-left:4px solid var(--green);line-height:1.65;margin-top:18px}.formula-list{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:10px;margin-top:14px}.formula{padding:12px 14px;background:#f6faf8;border:1px solid #dbeae3;font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;color:#173c31}.steps{padding-left:22px}.steps li{margin:8px 0}.practice{background:#fcf7f6;border:1px solid #f0d8d6;padding:20px}.practice label{display:block;font-weight:800;line-height:1.55;margin-bottom:14px}.answer-row{display:flex;gap:10px}.answer{flex:1;min-width:0;padding:13px;border:1px solid #c8d8d0;font:inherit}.check,.complete{border:0;background:var(--green);color:#fff;padding:13px 18px;font-weight:900;cursor:pointer}.check:hover,.complete:hover{filter:brightness(.93)}.feedback{margin-top:12px;font-weight:800;min-height:20px}.feedback.ok{color:var(--green)}.feedback.bad{color:var(--red)}.sidebar{position:sticky;top:100px}.sidebar-card{padding:22px;margin-bottom:16px}.sidebar-card a{display:block;padding:10px 0;border-bottom:1px solid #edf2ef;color:var(--green);font-weight:800;text-decoration:none}.sidebar-card a:last-child{border-bottom:0}.complete{width:100%}.complete.done{background:#e8f7ef;color:#176b49;border:1px solid #add9c5}.lesson-nav{display:flex;justify-content:space-between;gap:14px;margin-top:26px}.lesson-nav a{padding:14px 18px;border:1px solid #bed4ca;color:var(--dark);font-weight:900;text-decoration:none;background:#fff}.lesson-nav a:hover{border-color:var(--green);color:var(--green)}.tip{border:1px solid #f0d7a0;background:#fffaf0;padding:16px 18px;margin-top:18px;line-height:1.6}.footer{border-top:1px solid var(--line);padding:30px 0;background:#f6faf8}.footer-inner{display:flex;justify-content:space-between;align-items:center;gap:20px;color:var(--muted);font-size:13px}
@media(max-width:960px){.nav{display:none}.hero-grid,.lesson-layout{grid-template-columns:1fr}.task-grid{grid-template-columns:repeat(2,minmax(0,1fr))}.sidebar{position:static}.side-card{max-width:520px}}@media(max-width:640px){.container{width:min(100% - 24px,1180px)}.top-inner{min-height:68px}.brand{font-size:23px}.hero,.lesson-hero{padding:38px 0}.hero h1,.lesson-hero h1{letter-spacing:-1.5px}.hero p,.lesson-hero p{font-size:16px}.task-grid{grid-template-columns:1fr}.section{padding:42px 0 60px}.section-head{align-items:flex-start;flex-direction:column}.answer-row{flex-direction:column}.formula-list{grid-template-columns:1fr}.footer-inner{align-items:flex-start;flex-direction:column}}