/* ===== ТурбоУчебник header v3: cache-safe, isolated logo ===== */
.topbar{min-height:76px;height:76px;overflow:visible}
.tb-logo{display:inline-flex;align-items:center;gap:0;min-width:430px;max-width:max-content;text-decoration:none;color:inherit;white-space:nowrap;line-height:1;overflow:visible}
.tb-logo-main{display:inline-flex;align-items:center;gap:10px;flex:0 0 auto;overflow:visible}
.tb-logo-word{display:inline-flex;align-items:baseline;font-size:26px;font-weight:900;letter-spacing:-.04em;line-height:1}
.tb-logo-speedo{display:block;flex:0 0 auto;width:48px!important;height:36px!important;max-width:48px!important;max-height:36px!important;overflow:visible}
.tb-logo-speedo .seg{fill:none;stroke-width:5.5;stroke-linecap:butt}
.tb-logo-speedo .seg.red{stroke:var(--r)}
.tb-logo-speedo .seg.green{stroke:var(--g)}
.tb-logo-speedo .needle{stroke:var(--r);stroke-width:4;stroke-linecap:round}
.tb-logo-speedo .hub{fill:var(--r)}
.tb-logo-divider{width:1px;height:27px;background:var(--line);margin:0 16px;flex:0 0 auto}
.tb-logo-product{display:inline-flex;align-items:baseline;font-size:20px;font-weight:900;letter-spacing:-.035em;line-height:1;flex:0 0 auto}
@media(max-width:950px){.tb-logo{min-width:0;flex:1}.tb-logo-product{font-size:17px}.tb-logo-divider{margin:0 11px}}
@media(max-width:600px){.topbar{min-height:70px;height:70px}.tb-logo-word{font-size:20px}.tb-logo-speedo{width:38px!important;height:29px!important;max-width:38px!important;max-height:29px!important}.tb-logo-divider{height:23px;margin:0 8px}.tb-logo-product{font-size:15px}}
*{box-sizing:border-box} :root{--bg:#f4f7f5;--s:#fff;--s2:#eaf2ed;--t:#102019;--m:#687a71;--g:#087e50;--r:#df293f;--line:#d7e3dc;--dark:#071510;--sh:0 18px 50px rgba(8,43,29,.10)}
html[data-theme=dark]{--bg:#090d0b;--s:#101713;--s2:#18221d;--t:#f3f7f5;--m:#9caf9f;--line:#29382f;--dark:#020403;--sh:0 18px 50px rgba(0,0,0,.35)}
body{margin:0;background:var(--bg);color:var(--t);font:15px/1.5 Inter,Segoe UI,Arial,sans-serif}.topbar{height:76px;padding:0 4vw;display:flex;align-items:center;gap:28px;border-bottom:1px solid var(--line);background:color-mix(in srgb,var(--s) 92%,transparent);position:sticky;top:0;z-index:20;backdrop-filter:blur(14px)}
.brand{display:flex;align-items:center;gap:18px;text-decoration:none;color:inherit;min-width:410px;white-space:nowrap}.brand-main{display:flex;align-items:center;gap:9px}.brand-word{font-size:26px;font-weight:900;letter-spacing:-.035em;line-height:1}.brand-product{font-size:18px;font-weight:900;letter-spacing:-.025em;padding-left:18px;border-left:1px solid var(--line);line-height:1}.r{color:var(--r)}.g{color:var(--g)}.brand-speedo{width:45px;height:34px;overflow:visible}.brand-speedo path{fill:none;stroke:var(--g);stroke-width:6;stroke-linecap:butt}.brand-speedo path:first-child{stroke:var(--r)}.brand-speedo line{stroke:var(--r);stroke-width:4;stroke-linecap:round}.brand-speedo circle{fill:var(--r)}
nav{display:flex;gap:7px;flex:1}button{font:inherit}.topbar button{border:0;background:transparent;color:var(--m);font-weight:800;padding:10px 12px;border-radius:10px;cursor:pointer}.topbar button:hover{background:var(--s2);color:var(--t)}
main{max-width:1380px;margin:auto;padding:36px 4vw 70px}.hero,.panel,.card,.topic,.lesson-card,.quiz,.stat{background:var(--s);border:1px solid var(--line);box-shadow:var(--sh);border-radius:26px}.hero{padding:54px;display:grid;grid-template-columns:1.4fr .65fr;gap:40px}.ey{font-size:12px;font-weight:900;letter-spacing:.15em;color:var(--g)}h1{font-size:clamp(40px,5vw,70px);line-height:.98;letter-spacing:-.045em;margin:14px 0 20px}.hero p,.lead{font-size:18px;color:var(--m);max-width:850px}.hero-badge{background:linear-gradient(140deg,var(--dark),#153e2f);color:#fff;border-radius:24px;padding:32px;display:flex;flex-direction:column;justify-content:center}.hero-badge strong{font-size:52px}.hero-badge span{color:#b9cec4}
.primary,.secondary{padding:14px 18px;border-radius:13px;font-weight:900;cursor:pointer}.primary{background:var(--g);color:#fff;border:0}.secondary{background:var(--s);border:1px solid var(--line);color:var(--t)}.actions{display:flex;gap:10px;margin-top:26px}
.section-title{display:flex;align-items:end;justify-content:space-between;margin:48px 0 18px}.section-title h2{font-size:34px;margin:4px 0}.grades{display:grid;grid-template-columns:repeat(6,1fr);gap:14px}.grade{background:var(--s);border:1px solid var(--line);border-radius:20px;padding:23px;cursor:pointer;transition:.2s;box-shadow:var(--sh)}.grade:hover{transform:translateY(-3px);border-color:var(--g)}.grade b{font-size:32px}.grade small{display:block;color:var(--m)}
.breadcrumbs{color:var(--m);margin-bottom:18px}.back{border:0;background:none;color:var(--g);font-weight:900;cursor:pointer;padding:0}.grid{display:grid;grid-template-columns:repeat(4,1fr);gap:16px}.card{padding:25px;min-height:215px;position:relative}.card h3{font-size:22px;margin:20px 0 8px}.card p{color:var(--m)}.subject-icon{font-size:40px;font-weight:900;color:var(--g)}.inactive{opacity:.55}.pill{display:inline-block;border-radius:999px;background:var(--s2);padding:6px 9px;font-size:11px;font-weight:900}.pill.frp{background:#dff5e9;color:#075f3d}.pill.extra{background:#fde7eb;color:#9c1f32}.open{position:absolute;right:22px;bottom:20px;color:var(--g);font-weight:900;cursor:pointer}
.topic-list{display:grid;gap:12px}.topic{padding:22px 24px;display:grid;grid-template-columns:1fr auto;align-items:center}.topic h3{margin:4px 0}.topic p{color:var(--m);margin:0}.topic button{border:0;background:var(--g);color:#fff;border-radius:11px;padding:12px 15px;font-weight:900}.topic.soon button{background:var(--s2);color:var(--m)}
.lesson-layout{display:grid;grid-template-columns:260px 1fr;gap:22px}.lesson-menu{background:var(--dark);color:#fff;border-radius:22px;padding:22px;height:max-content}.lesson-menu button{display:block;width:100%;border:0;text-align:left;background:transparent;color:#adc0b7;padding:10px;border-radius:8px}.lesson-menu button.on{background:#17372b;color:#fff}.lesson-card{padding:36px}.lesson-card h1{font-size:48px}.theory{padding:24px;border-radius:18px;background:var(--s2);margin:22px 0}.powers{display:grid;grid-template-columns:repeat(5,1fr);gap:8px;margin-top:18px}.powers span{text-align:center;background:var(--s);padding:15px;border-radius:12px}.powers b{display:block;color:var(--g);font-size:22px}.binary{display:flex;gap:8px;margin:24px 0}.binary span{min-width:70px;background:var(--s2);padding:14px;text-align:center;border-radius:12px;font-size:32px;font-weight:900}.quiz{padding:30px;margin-top:24px}.quiz .q{font-size:42px;font-weight:900;margin:20px 0}.answer{display:flex;gap:10px}.answer input{flex:1;background:var(--bg);border:2px solid var(--line);color:var(--t);border-radius:12px;padding:14px;font-size:22px}.fb{margin-top:14px;padding:13px;border-radius:11px}.ok{background:#dff5e9;color:#075f3d}.bad{background:#fde7eb;color:#9c1f32}.hidden{display:none}.stats{display:grid;grid-template-columns:repeat(4,1fr);gap:15px}.stat{padding:24px}.stat small{display:block;color:var(--m)}.stat b{font-size:34px}.progressbar{height:10px;background:var(--s2);border-radius:20px;overflow:hidden}.progressbar span{display:block;height:100%;background:linear-gradient(90deg,var(--r),var(--g))}
footer{padding:28px 4vw;border-top:1px solid var(--line);display:flex;justify-content:space-between;color:var(--m);font-size:13px}
@media(max-width:950px){.hero,.lesson-layout{grid-template-columns:1fr}.grid{grid-template-columns:1fr 1fr}.grades{grid-template-columns:repeat(3,1fr)}nav{display:none}.brand{min-width:0;flex:1}.brand-product{font-size:16px}.stats{grid-template-columns:1fr 1fr}}
@media(max-width:600px){.topbar{gap:10px}.brand{gap:10px}.brand-word{font-size:21px}.brand-speedo{width:36px;height:28px}.brand-product{font-size:15px;padding-left:10px}main{padding:22px}.hero{padding:28px}.grid{grid-template-columns:1fr}.grades{grid-template-columns:repeat(2,1fr)}h1{font-size:42px}.lesson-card{padding:24px}.lesson-card h1{font-size:38px}.powers{grid-template-columns:repeat(5,1fr)}.binary{flex-wrap:wrap}.answer{flex-direction:column}footer{flex-direction:column;gap:10px}}

/* ===== ТурбоУчебник v4 — exact brand image ===== */
.tb-brand-image{display:flex;align-items:center;flex:0 1 650px;min-width:360px;max-width:650px;height:64px;text-decoration:none;overflow:visible}
.tb-brand-image img{display:block;width:100%;height:auto;max-height:58px;object-fit:contain;object-position:left center}
.user-chip{display:flex;align-items:center;gap:8px;white-space:nowrap;font-size:12px;color:var(--m);font-weight:700}
.user-chip a{color:var(--g);text-decoration:none}.user-chip .role{padding:4px 7px;border-radius:999px;background:var(--s2)}
.login-note{border:1px solid var(--line);background:var(--s);border-radius:18px;padding:24px;margin:22px 0}.login-note h3{margin-top:0}.login-note p{color:var(--m)}
.assignments{display:grid;gap:12px}.assignment{background:var(--s);border:1px solid var(--line);border-radius:18px;padding:20px;display:grid;grid-template-columns:1fr auto;gap:16px;align-items:center}.assignment.done{border-color:#80cda8}.assignment small{color:var(--m)}
.student-list{display:grid;gap:12px}.student-row{background:var(--s);border:1px solid var(--line);border-radius:18px;padding:18px 20px;display:grid;grid-template-columns:1fr auto;gap:12px;align-items:center}.student-row small{display:block;color:var(--m)}
.tutor-tools{display:flex;gap:8px;flex-wrap:wrap}.mini-btn{border:1px solid var(--line)!important;background:var(--s2)!important;color:var(--t)!important;padding:9px 12px!important;border-radius:10px!important;font-weight:800!important;cursor:pointer}.mini-btn.primary-mini{background:var(--g)!important;color:white!important;border-color:var(--g)!important}
.modal-backdrop{position:fixed;inset:0;background:#0008;z-index:99;display:grid;place-items:center;padding:20px}.modal{width:min(560px,100%);background:var(--s);color:var(--t);border:1px solid var(--line);border-radius:22px;padding:28px;box-shadow:var(--sh)}.modal label{display:block;margin:14px 0 5px;font-weight:800}.modal input,.modal select{width:100%;padding:12px;border:1px solid var(--line);background:var(--bg);color:var(--t);border-radius:10px}.modal-actions{display:flex;justify-content:flex-end;gap:8px;margin-top:20px}
@media(max-width:1100px){.tb-brand-image{flex-basis:520px;min-width:300px}.tb-brand-image img{max-height:50px}.user-chip{display:none}}
@media(max-width:760px){.tb-brand-image{min-width:0;flex:1;height:56px}.tb-brand-image img{max-height:43px}.assignment,.student-row{grid-template-columns:1fr}.topbar{padding-left:12px;padding-right:12px}}