:root{--clr-brand:#2563eb;--clr-brand-dark:#1d4ed8;--clr-primary:var(--clr-brand);--clr-primary-dark:var(--clr-brand-dark);--clr-focus-ring:#2563eba6;--clr-backdrop:#00000080;--clr-student:var(--clr-emerald);--clr-student-dark:var(--clr-emerald-dark);--clr-teacher:var(--clr-sky);--clr-teacher-dark:var(--clr-sky-dark);--clr-success:#22c55e;--clr-danger:#ef4444;--clr-danger-light:#fee2e2;--clr-danger-soft:#fecaca;--clr-warning:#f59e0b;--clr-warning-light:#fef3c7;--clr-warning-text:#78350f;--fb-ok-bg:#ecfdf5;--fb-ok-border:#34d399;--fb-ok-text:#065f46;--fb-err-bg:#fff1f2;--fb-err-border:#f87171;--fb-err-text:#9f1239;--fb-err-label:#e11d48;--fb-ok-soft:#15803d;--fb-err-soft:#b91c1c;--clr-surface:#fff;--clr-surface-muted:#f0f4ff;--clr-surface-subtle:#e8eeff;--clr-border:#dde3f0;--clr-border-light:#dde3f099;--clr-text:#0a0f1e;--clr-text-muted:#4b5680;--clr-text-faint:#5b6584;--clr-text-inverse:#fff;--sp-1:.25rem;--sp-2:.5rem;--sp-3:.75rem;--sp-4:1rem;--sp-5:1.25rem;--sp-6:1.5rem;--sp-7:1.75rem;--sp-8:2rem;--sp-10:2.5rem;--sp-12:3rem;--sp-14:3.5rem;--sp-16:4rem;--sp-20:5rem;--sp-24:6rem;--r-sm:.5rem;--r-md:1rem;--r-lg:1.25rem;--r-xl:1.75rem;--r-2xl:2.5rem;--r-3xl:3rem;--r-full:9999px;--shadow-card:0 24px 64px -12px #2563eb1f, 0 4px 16px -4px #2563eb0f;--shadow-btn:0 8px 24px #2563eb40;--shadow-sm:0 1px 4px #0a0f1e0f;--shadow-md:0 4px 20px #0a0f1e1a;--shadow-lg:0 12px 40px #0a0f1e24;--transition-fast:.15s ease;--transition-base:.2s ease;--transition-slow:.3s ease;--font-family:"Nunito", sans-serif;--font-size-xs:.75rem;--font-size-sm:.875rem;--font-size-base:1rem;--font-size-lg:1.125rem;--font-size-xl:1.25rem;--font-size-2xl:1.5rem;--font-size-3xl:1.875rem;--font-size-4xl:2.25rem;--font-size-5xl:3rem;--font-size-hero:clamp(2.75rem, 7vw, 4.5rem);--clr-mascot:var(--clr-warning);--clr-mascot-light:var(--clr-warning-light);--track-inf:#0d9488;--track-inf-light:#ccfbf1;--track-inf-dark:#115e59;--track-think:#7c3aed;--track-think-light:#ede9fe;--track-think-dark:#5b21b6;--track-ai:#ea580c;--track-ai-light:#ffedd5;--track-ai-dark:#9a3412;--kid-text:1.125rem;--kid-tap:3.5rem;--kid-tap-lg:4.5rem;--student-bg-from:#6366f1;--student-bg-to:#3b82f6;--clr-violet:#4f46e5;--clr-violet-dark:#4338ca;--clr-violet-light:#e0e7ff;--clr-amber:#fbbf24;--clr-amber-dark:var(--clr-warning);--clr-sky:#0284c7;--clr-sky-dark:#0369a1;--clr-sky-light:#dbeafe;--clr-emerald:#10b981;--clr-emerald-dark:#059669;--clr-emerald-light:#d1fae5;--adm-bg:#060b18;--adm-surface:#0f172a;--adm-surface-2:#060b18;--adm-border:#1e2d4a;--adm-text:#f1f5f9;--adm-text-muted:#8892b0;--adm-text-faint:#8b98bd;--adm-sky:#60a5fa;--adm-emerald:var(--clr-emerald);--adm-emerald-hover:var(--clr-emerald-dark);--adm-violet:#7c3aed;--adm-violet-hover:#6d28d9;--adm-rose:#f43f5e}@font-face{font-family:Nunito;font-style:normal;font-weight:400 800;font-display:swap;src:url(/fonts/nunito-cyrillic.woff2)format("woff2");unicode-range:U+301,U+400-45F,U+490-491,U+4B0-4B1,U+2116}@font-face{font-family:Nunito;font-style:normal;font-weight:400 800;font-display:swap;src:url(/fonts/nunito-cyrillic-ext.woff2)format("woff2");unicode-range:U+460-52F,U+1C80-1C8A,U+20B4,U+2DE0-2DFF,U+A640-A69F,U+FE2E-FE2F}@font-face{font-family:Nunito;font-style:normal;font-weight:400 800;font-display:swap;src:url(/fonts/nunito-latin.woff2)format("woff2");unicode-range:U+??,U+131,U+152-153,U+2BB-2BC,U+2C6,U+2DA,U+2DC,U+304,U+308,U+329,U+2000-206F,U+20AC,U+2122,U+2191,U+2193,U+2212,U+2215,U+FEFF,U+FFFD}*,:before,:after{box-sizing:border-box;margin:0;padding:0}body{font-family:var(--font-family);color:var(--clr-text);-webkit-font-smoothing:antialiased;min-width:320px;line-height:1.6;overflow-x:clip}a{color:inherit;text-decoration:none}img{max-width:100%;height:auto;display:block}.hidden{display:none!important}button{cursor:pointer;background:0 0;border:none;font-family:inherit}.sr-only{clip:rect(0,0,0,0);clip-path:inset(50%);white-space:nowrap;border:0;width:1px;height:1px;margin:-1px;padding:0;position:absolute;overflow:hidden}.skip-link{top:var(--sp-4);left:var(--sp-4);z-index:10000;padding:var(--sp-3) var(--sp-4);background:var(--clr-brand-dark);color:var(--clr-text-inverse);font-weight:600;font-size:var(--font-size-sm);border-radius:var(--r-sm);clip:rect(1px,1px,1px,1px);clip-path:inset(50%);white-space:nowrap;width:1px;height:1px;transition:clip-path var(--transition-fast);position:absolute;overflow:hidden}.skip-link:focus-visible{clip:auto;clip-path:none;width:auto;height:auto;overflow:visible}@media (prefers-reduced-motion:reduce){*,:before,:after{scroll-behavior:auto!important;transition-duration:.01ms!important;animation-duration:.01ms!important;animation-iteration-count:1!important}}:focus-visible{outline:3px solid var(--clr-brand);outline-offset:2px}.btn{justify-content:center;align-items:center;gap:var(--sp-2);font-family:var(--font-family);font-size:var(--font-size-base);min-height:2.75rem;padding:var(--sp-3) var(--sp-5);border-radius:var(--r-lg);cursor:pointer;transition:background-color var(--transition-base), color var(--transition-base), border-color var(--transition-base), box-shadow var(--transition-base), filter var(--transition-fast), transform var(--transition-fast);border:none;font-weight:700;display:inline-flex}.btn:hover:not(:disabled){box-shadow:var(--shadow-btn)}.btn:active:not(:disabled){transform:translateY(1px)}.btn:focus-visible{outline:3px solid var(--clr-focus-ring);outline-offset:2px}.btn:disabled{cursor:not-allowed;opacity:.65}.btn--teacher{background:var(--clr-teacher-dark);color:var(--clr-text-inverse)}.btn--teacher:hover:not(:disabled){filter:brightness(.9)}.btn--success{background:var(--fb-ok-soft);color:var(--clr-text-inverse)}.btn--success:hover:not(:disabled){filter:brightness(.9)}.btn--secondary{background:var(--clr-surface-subtle);color:var(--clr-text-muted);font-size:var(--font-size-sm);padding:var(--sp-2) var(--sp-4);font-weight:500}.btn--secondary:hover:not(:disabled){background:var(--clr-border)}.btn--danger{background:var(--fb-err-soft);color:var(--clr-text-inverse)}.btn--danger:hover:not(:disabled){background:var(--fb-err-text)}.btn--sm{min-height:2.25rem;padding:var(--sp-2) var(--sp-3);font-size:var(--font-size-sm)}.btn--full{width:100%}.modal-overlay{z-index:100;background:var(--clr-backdrop);padding:var(--sp-4);animation:fadeIn var(--transition-slow);justify-content:center;align-items:center;display:none;position:fixed;inset:0;overflow-y:auto}.modal-overlay:not(.hidden){display:flex}.modal-content{animation:slideUp var(--transition-slow);margin:auto}.cert-modal-overlay{z-index:1000;padding:var(--sp-4);background:var(--clr-backdrop);justify-content:center;align-items:center;display:flex;position:fixed;inset:0;overflow-y:auto}.cert-modal{width:100%;max-width:30rem;padding:var(--sp-8);border:1px solid var(--clr-border);border-radius:var(--r-xl);background:var(--clr-surface);box-shadow:var(--shadow-lg);margin:auto}.cert-modal__title{margin-bottom:var(--sp-2);color:var(--clr-text);font-size:var(--font-size-lg);font-weight:700}.cert-modal__hint{margin-bottom:var(--sp-4);color:var(--clr-text-muted);font-size:var(--font-size-sm)}.cert-modal__field label{margin-bottom:var(--sp-2);color:var(--clr-text);font-size:var(--font-size-sm);font-weight:600;display:block}.cert-modal__input{width:100%;margin-bottom:var(--sp-6);padding:var(--sp-3);border:1px solid var(--clr-border);border-radius:var(--r-md);background:var(--clr-surface);color:var(--clr-text);font:inherit}.cert-modal__input:focus-visible{outline:3px solid var(--clr-focus-ring);outline-offset:2px}.cert-modal__input--invalid{border-color:var(--clr-danger)}.cert-modal__actions{gap:var(--sp-3);flex-wrap:wrap;display:flex}.lightbox{z-index:200;padding:var(--sp-4);cursor:zoom-out;background:#000000d9;justify-content:center;align-items:center;animation:.2s fadeIn;display:none;position:fixed;inset:0}.lightbox:not(.hidden){display:flex}.lightbox__img{border-radius:var(--r-xl);object-fit:contain;-webkit-user-select:none;user-select:none;max-width:min(90vw,900px);max-height:90vh;animation:.25s slideUp;box-shadow:0 30px 80px #00000080}.lightbox__close{top:var(--sp-4);right:var(--sp-4);border-radius:var(--r-full);width:2.5rem;height:2.5rem;color:var(--clr-text-inverse);font-size:var(--font-size-xl);transition:background-color var(--transition-fast);background:#fff3;justify-content:center;align-items:center;display:flex;position:absolute}.lightbox__close:hover{background:#ffffff59}.quiz-image-btn{cursor:zoom-in}.quiz-image-btn:focus-visible{outline:3px solid var(--clr-focus-ring);outline-offset:3px}@keyframes fadeIn{0%{opacity:0}to{opacity:1}}@keyframes slideUp{0%{opacity:0;transform:translateY(20px)}to{opacity:1;transform:translateY(0)}}.index-page{background:linear-gradient(160deg, var(--clr-surface-subtle) 0%, var(--clr-surface-muted) 50%, var(--clr-sky-light) 100%);min-height:100dvh}.site-header{background:var(--clr-surface);border-bottom:1px solid var(--clr-border);padding:var(--sp-3) var(--sp-6);box-shadow:var(--shadow-sm);z-index:100;position:sticky;top:0}.site-header__inner{justify-content:space-between;align-items:center;gap:var(--sp-4);min-width:0;max-width:80rem;margin:0 auto;display:flex}.site-header__logo{flex-shrink:0;align-items:center;text-decoration:none;display:flex}.site-header__logo img{width:auto;height:34px;display:block}.site-header__logo:hover{opacity:.85}.site-header__nav{justify-content:center;align-items:center;gap:var(--sp-1) var(--sp-4);flex-wrap:wrap;flex:1;min-width:0;display:flex}.site-header__link{font-size:var(--font-size-sm);color:var(--clr-text-muted);transition:color var(--transition-fast);white-space:nowrap;font-weight:600;text-decoration:none}.site-header__link:hover,.site-header__link--active{color:var(--clr-primary)}.site-header__cta{font-size:var(--font-size-sm);color:var(--clr-text-inverse);background:var(--clr-primary);padding:6px var(--sp-4);border-radius:var(--r-full);white-space:nowrap;transition:background var(--transition-fast), box-shadow var(--transition-fast);flex-shrink:0;font-weight:700;text-decoration:none;box-shadow:0 2px 8px #3b82f659}.site-header__cta:hover{background:var(--clr-primary-dark);box-shadow:0 4px 12px #3b82f673}.site-header__actions{align-items:center;gap:var(--sp-3);flex-shrink:0;display:flex}.site-header__teacher{font-size:var(--font-size-sm);color:var(--clr-primary);padding:5px var(--sp-4);border-radius:var(--r-full);border:2px solid var(--clr-primary);white-space:nowrap;transition:background var(--transition-fast), color var(--transition-fast);font-weight:700;text-decoration:none}.site-header__teacher:hover{background:var(--clr-primary);color:var(--clr-text-inverse)}.site-header__mobile-only{display:none}.site-header__burger{cursor:pointer;background:0 0;border:none;flex-direction:column;flex-shrink:0;justify-content:center;align-items:center;gap:5px;width:44px;height:44px;padding:0;display:none}.site-header__burger span{background:var(--clr-text);border-radius:2px;width:22px;height:2px;transition:transform .2s,opacity .2s;display:block}@media (width<=640px){.site-header{padding:var(--sp-3) var(--sp-4)}.site-header__burger{display:flex}.site-header__cta,.site-header__actions{display:none}.site-header__mobile-only{display:block}.site-header__nav{background:var(--clr-surface);border-bottom:1px solid var(--clr-border);box-shadow:var(--shadow-md);padding:var(--sp-2) var(--sp-4) var(--sp-3);flex-direction:column;align-items:stretch;gap:0;display:none;position:absolute;top:100%;left:0;right:0}.site-header__link{padding:var(--sp-3) 0;border-bottom:1px solid var(--clr-border);font-size:var(--font-size-base)}.site-header__link:last-child{border-bottom:none}.site-header.is-open .site-header__nav{display:flex}.site-header.is-open .site-header__burger span:first-child{transform:translateY(7px)rotate(45deg)}.site-header.is-open .site-header__burger span:nth-child(2){opacity:0}.site-header.is-open .site-header__burger span:nth-child(3){transform:translateY(-7px)rotate(-45deg)}}.site-footer{padding:var(--sp-8) var(--sp-4);color:var(--clr-text-muted);font-size:var(--font-size-sm)}.site-footer__inner{max-width:42rem;margin:0 auto}.site-footer__nav{gap:var(--sp-6);margin-bottom:var(--sp-6);text-align:center;grid-template-columns:repeat(2,minmax(0,1fr));display:grid}@media (width>=640px){.site-footer__nav{text-align:left;grid-template-columns:repeat(3,minmax(0,1fr))}}.footer-col__heading{font-size:var(--font-size-xs);text-transform:uppercase;letter-spacing:.08em;color:var(--clr-text-muted);margin-bottom:var(--sp-2);font-weight:600}.footer-col__list{gap:var(--sp-2);flex-direction:column;list-style:none;display:flex}.footer-col__list a{color:var(--clr-text-muted);font-size:var(--font-size-sm);transition:color var(--transition-fast)}.footer-col__list a:hover{color:var(--clr-text)}.footer-col--wide{text-align:center;grid-column:span 2}@media (width>=640px){.footer-col--wide{text-align:left;grid-column:span 1}}.site-footer__copy{border-top:1px solid var(--clr-border);padding-top:var(--sp-4);text-align:center;font-size:var(--font-size-xs);color:var(--clr-text-faint)}