:root{--ink:#173344;--muted:#607784;--teal:#0f766e;--teal2:#11998e;--blue:#154c79;--gold:#f4b942;--cream:#fff8e8;--mist:#edf6f5;--line:#d6e4e3;--danger:#b42318;--shadow:0 18px 50px rgba(23,51,68,.11);font-family:Inter,ui-sans-serif,system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;color:var(--ink);background:#f6faf9}
*{box-sizing:border-box}body{margin:0;min-height:100vh;background:radial-gradient(circle at 90% 0,#d9f3ef 0,transparent 32rem),#f6faf9;color:var(--ink)}button,input{font:inherit}button{cursor:pointer}.topbar{height:76px;padding:0 max(20px,calc((100vw - 1120px)/2));display:flex;align-items:center;justify-content:space-between;background:rgba(255,255,255,.9);border-bottom:1px solid var(--line);position:sticky;top:0;z-index:10;backdrop-filter:blur(14px)}.brand{display:flex;align-items:center;gap:12px;color:var(--ink);text-decoration:none}.brand-mark{width:44px;height:44px;border-radius:14px;display:grid;place-items:center;background:linear-gradient(135deg,var(--teal),var(--blue));color:#fff;font-weight:900}.brand strong,.brand small{display:block}.brand small{color:var(--muted);margin-top:2px}.icon-button,.back-button{border:0;background:transparent;color:var(--teal);font-weight:800;padding:10px 12px;border-radius:10px}.icon-button:hover,.back-button:hover{background:var(--mist)}.shell{width:min(1120px,calc(100% - 32px));margin:0 auto}.view{display:none;padding:52px 0 70px}.view.active{display:block}.eyebrow{display:block;color:var(--teal);font-size:.78rem;letter-spacing:.11em;text-transform:uppercase;font-weight:900;margin-bottom:10px}.hero{display:grid;grid-template-columns:1fr 240px;gap:48px;align-items:center;padding:54px;border-radius:30px;background:linear-gradient(135deg,#fff 0,#effaf8 100%);box-shadow:var(--shadow);border:1px solid #e1eeec}.hero h1,.lesson-head h1,.result-card h1{font-size:clamp(2.25rem,5vw,4.7rem);line-height:1.02;letter-spacing:-.045em;margin:0 0 22px}.hero p,.lesson-head p{font-size:1.18rem;line-height:1.7;color:#476473;max-width:760px}.hero-score{min-height:210px;border-radius:24px;padding:28px;background:linear-gradient(150deg,var(--teal),#0b4b64);color:#fff;display:flex;flex-direction:column;justify-content:center;align-items:center;text-align:center}.score-label{font-size:.85rem;opacity:.8}.hero-score strong{font-size:3rem;margin:8px 0 14px}.streak-dots{display:flex;gap:9px}.streak-dots i{width:13px;height:13px;border-radius:50%;background:rgba(255,255,255,.25)}.streak-dots i.on{background:var(--gold);box-shadow:0 0 0 5px rgba(244,185,66,.16)}.teacher-note{display:flex;gap:15px;align-items:flex-start;margin:24px 0 44px;padding:18px 22px;border:1px solid #f1d88c;background:var(--cream);border-radius:16px}.teacher-note p{margin:0;line-height:1.55}.note-icon{flex:0 0 28px;height:28px;border-radius:50%;display:grid;place-items:center;background:var(--gold);font-weight:900}.section-heading{display:flex;justify-content:space-between;gap:16px;align-items:end;margin:0 0 20px}.section-heading h2{font-size:2rem;margin:0}.saved-state{color:var(--teal);font-size:.9rem;font-weight:800}.module-card{display:grid;grid-template-columns:96px 1fr auto;gap:24px;align-items:center;padding:28px;margin:18px 0;border-radius:22px;background:#fff;border:1px solid var(--line);box-shadow:0 10px 32px rgba(23,51,68,.06)}.module-card.locked{opacity:.68;background:#f0f4f4}.module-number{font-size:2.3rem;font-weight:900;color:var(--teal);text-align:center}.module-copy h3{font-size:1.45rem;margin:5px 0 8px}.module-copy p{color:var(--muted);line-height:1.6;margin:0}.module-status{font-size:.75rem;text-transform:uppercase;letter-spacing:.08em;font-weight:900;color:var(--teal)}.module-meta{display:flex;gap:8px;flex-wrap:wrap;margin-top:14px}.module-meta span,.lock-badge{font-size:.78rem;font-weight:800;padding:7px 10px;border-radius:999px;background:var(--mist);color:var(--teal)}.primary-button,.secondary-button,.danger-button{border:0;border-radius:13px;padding:14px 20px;font-weight:900;transition:.2s transform,.2s box-shadow}.primary-button{background:linear-gradient(135deg,var(--teal),#0a5f75);color:#fff;box-shadow:0 10px 24px rgba(15,118,110,.22)}.secondary-button{background:#fff;border:1px solid var(--teal);color:var(--teal)}.danger-button{background:#fff0ee;color:var(--danger);margin-top:20px}.primary-button:hover,.secondary-button:hover{transform:translateY(-2px)}.lesson-head{max-width:870px;margin:35px 0 36px}.lesson-head h1{font-size:clamp(2.2rem,5vw,4.1rem)}.concept-grid{display:grid;grid-template-columns:1fr 1fr;gap:18px}.concept-card{padding:28px;border-radius:20px;background:#fff;border:1px solid var(--line);box-shadow:0 10px 26px rgba(23,51,68,.05)}.concept-card span{font-weight:900;color:var(--teal)}.concept-card strong{display:block;font-size:clamp(2rem,5vw,3.4rem);margin:18px 0 10px}.concept-card p{color:var(--muted);margin:0}.rule-card{margin:22px 0;padding:30px;border-radius:20px;background:var(--ink);color:#fff}.rule-card h2{margin:0 0 18px}.rule-card ol{list-style:none;padding:0;margin:0;display:grid;grid-template-columns:repeat(3,1fr);gap:15px;counter-reset:step}.rule-card li{counter-increment:step;padding:18px;border-radius:14px;background:rgba(255,255,255,.08)}.rule-card li:before{content:counter(step);display:grid;place-items:center;width:28px;height:28px;border-radius:50%;background:var(--gold);color:var(--ink);font-weight:900;margin-bottom:12px}.rule-card strong,.rule-card span{display:block}.rule-card span{font-size:.9rem;line-height:1.5;opacity:.78;margin-top:7px}.lesson-actions,.result-actions{display:flex;justify-content:flex-end;gap:12px;margin-top:26px}.session-bar{display:grid;grid-template-columns:1fr 1fr 1fr;align-items:center;margin-bottom:16px}.session-bar>div:nth-child(2){text-align:center}.session-bar span{display:block;font-size:.8rem;color:var(--muted);font-weight:800}.timer{text-align:right}.progress-track{height:8px;background:#dbe9e7;border-radius:10px;overflow:hidden}.progress-track span{display:block;width:0;height:100%;background:linear-gradient(90deg,var(--teal2),var(--gold));transition:width .25s}.exercise-card{width:min(720px,100%);margin:36px auto 0;padding:42px;border-radius:28px;background:#fff;border:1px solid var(--line);box-shadow:var(--shadow);text-align:center}.exercise-label{color:var(--muted);font-weight:800}.equation{display:flex;align-items:center;justify-content:center;gap:18px;font-size:clamp(2.6rem,10vw,5.7rem);font-weight:900;margin:30px 0}.equation input{width:clamp(110px,25vw,190px);height:1.2em;border:0;border-bottom:6px solid var(--teal);text-align:center;color:var(--ink);font-size:inherit;font-weight:inherit;outline:none;background:#f4faf9;border-radius:12px 12px 0 0}.feedback{min-height:28px;font-weight:800;color:var(--muted)}.feedback.correct{color:var(--teal)}.feedback.wrong{color:var(--danger)}.keypad{display:grid;grid-template-columns:repeat(3,1fr);gap:10px;margin-top:24px}.keypad button{min-height:60px;border:1px solid var(--line);border-radius:13px;background:#f8fbfb;color:var(--ink);font-size:1.35rem;font-weight:900}.keypad button:active{transform:scale(.97)}.keypad .key-action{font-size:.9rem;color:var(--danger)}.keypad .key-submit{background:var(--teal);color:#fff;border-color:var(--teal)}.session-tip{text-align:center;color:var(--muted);font-weight:800}.result-card{max-width:790px;margin:25px auto;padding:48px;border-radius:30px;background:#fff;border:1px solid var(--line);box-shadow:var(--shadow);text-align:center}.result-card h1{font-size:clamp(2.1rem,5vw,3.6rem)}.result-icon{display:grid;place-items:center;width:74px;height:74px;border-radius:50%;margin:0 auto 22px;background:var(--mist);color:var(--teal);font-size:2.3rem;font-weight:900}.result-stats{display:grid;grid-template-columns:repeat(3,1fr);gap:12px;margin:30px 0}.result-stats div{padding:20px;border-radius:15px;background:#f2f7f6}.result-stats span,.result-stats strong{display:block}.result-stats span{color:var(--muted);font-size:.82rem}.result-stats strong{font-size:1.6rem;margin-top:6px}.teacher-check{text-align:left;padding:20px;border-radius:15px;background:var(--cream);border:1px solid #f1d88c}.teacher-check strong,.teacher-check span{display:block}.teacher-check span{color:#6d654e;margin-top:6px;line-height:1.5}dialog{width:min(720px,calc(100% - 28px));max-height:82vh;border:0;border-radius:24px;padding:28px;box-shadow:0 30px 90px rgba(0,0,0,.27)}dialog::backdrop{background:rgba(10,35,47,.65);backdrop-filter:blur(4px)}.dialog-head{display:flex;justify-content:space-between;align-items:start}.dialog-head h2{margin:0;font-size:2rem}.history-list{display:grid;gap:10px;margin-top:24px;max-height:52vh;overflow:auto}.history-item{display:grid;grid-template-columns:1fr auto;gap:14px;padding:15px;border:1px solid var(--line);border-radius:13px}.history-item strong,.history-item span{display:block}.history-item span{font-size:.83rem;color:var(--muted);margin-top:4px}.history-score{text-align:right;color:var(--teal);font-size:1.15rem}.empty-history{padding:35px;text-align:center;color:var(--muted);background:#f3f7f7;border-radius:14px}footer{width:min(1120px,calc(100% - 32px));margin:0 auto;padding:25px 0 45px;border-top:1px solid var(--line);display:flex;justify-content:space-between;color:var(--muted)}
@media(max-width:760px){.topbar{height:68px;padding:0 16px}.brand small{display:none}.shell{width:min(100% - 22px,1120px)}.view{padding:28px 0 52px}.hero{grid-template-columns:1fr;padding:26px;gap:20px;border-radius:22px}.hero h1{font-size:2.65rem}.hero-score{min-height:150px}.module-card{grid-template-columns:58px 1fr;padding:20px;gap:14px}.module-number{font-size:1.6rem}.module-card .primary-button,.module-card .lock-badge{grid-column:1/-1;width:100%;text-align:center}.concept-grid,.rule-card ol{grid-template-columns:1fr}.lesson-actions,.result-actions{flex-direction:column}.lesson-actions button,.result-actions button{width:100%}.session-bar{grid-template-columns:1fr 1fr}.session-bar>div:nth-child(2){order:3;grid-column:1/-1;margin-top:12px}.exercise-card{padding:24px 14px}.equation{gap:10px}.result-card{padding:30px 20px}.result-stats{grid-template-columns:1fr}.section-heading{align-items:start}.saved-state{display:none}footer{flex-direction:column;gap:6px}}
@media(prefers-reduced-motion:reduce){*{scroll-behavior:auto!important;transition:none!important}}