:root{color:#23314d;font-synthesis:none;text-rendering:optimizelegibility;-webkit-font-smoothing:antialiased;--navy:#23314d;--blue:#4f78d1;--blue-dark:#355da9;--blue-soft:#eaf0ff;--sage:#6fa78d;--sage-soft:#e9f4ee;--yellow:#f1c86a;--coral:#e68b74;--paper:#fff;--canvas:#f8faf7;--muted:#66728a;--border:#dde4e0;--shadow:0 18px 45px #23314d17;background:#f8faf7;font-family:ui-rounded,Segoe UI,system-ui,-apple-system,BlinkMacSystemFont,sans-serif}*{box-sizing:border-box}html{scroll-behavior:smooth}body{min-width:320px;min-height:100vh;margin:0}button,input,select,textarea{font:inherit}a{color:inherit}h1,h2,h3,p{margin-top:0}button:focus-visible,a:focus-visible,input:focus-visible,select:focus-visible,textarea:focus-visible{outline-offset:3px;outline:3px solid #4f78d159}#root{min-height:100vh}.app-shell{flex-direction:column;min-height:100vh;display:flex}main{flex:1}.skip-link{z-index:100;background:var(--navy);color:#fff;border-radius:8px;padding:10px 16px;position:fixed;top:-60px;left:16px}.skip-link:focus{top:12px}.site-header{z-index:20;-webkit-backdrop-filter:blur(14px);backdrop-filter:blur(14px);background:#f8faf7f0;border-bottom:1px solid #dde4e0d9;position:sticky;top:0}.header-inner{justify-content:space-between;align-items:center;gap:28px;width:min(1180px,100% - 40px);min-height:78px;margin:0 auto;display:flex}.brand{color:var(--navy);white-space:nowrap;align-items:center;gap:10px;font-size:1.15rem;font-weight:800;text-decoration:none;display:inline-flex}.brand-mark{background:var(--blue);color:#fff;border-radius:13px;place-items:center;width:42px;height:42px;font-size:.95rem;font-weight:800;display:inline-grid;box-shadow:0 8px 18px #4f78d13d}.brand-mark.small{border-radius:10px;width:34px;height:34px;font-size:.78rem}.main-nav{align-items:center;gap:4px;display:flex}.nav-link{color:#536077;white-space:nowrap;border-radius:10px;padding:9px 11px;font-size:.91rem;font-weight:700;text-decoration:none}.nav-link:hover,.nav-link.active{color:var(--blue-dark);background:var(--blue-soft)}.hero-section{grid-template-columns:1.05fr .95fr;align-items:center;gap:70px;width:min(1180px,100% - 40px);margin:0 auto;padding:84px 0 94px;display:grid}.eyebrow{color:var(--blue-dark);letter-spacing:.12em;text-transform:uppercase;margin-bottom:14px;font-size:.76rem;font-weight:800;display:inline-block}.hero-copy h1,.page-section h1{color:var(--navy);letter-spacing:-.045em;margin-bottom:24px;font-size:clamp(2.6rem,5vw,4.65rem);line-height:1.04}.hero-copy h1 span{color:var(--blue)}.hero-copy>p{max-width:620px;color:var(--muted);font-size:1.2rem;line-height:1.7}.hero-actions{flex-wrap:wrap;gap:12px;margin:32px 0 27px;display:flex}.button{cursor:pointer;border:0;border-radius:13px;justify-content:center;align-items:center;min-height:48px;padding:0 20px;font-weight:800;text-decoration:none;display:inline-flex}.button.primary{background:var(--blue);color:#fff;box-shadow:0 10px 22px #4f78d138}.button.primary:hover{background:var(--blue-dark)}.button.secondary{background:var(--paper);color:var(--navy);border:1px solid var(--border)}.trust-row{color:#637087;flex-wrap:wrap;gap:10px 20px;font-size:.84rem;font-weight:700;display:flex}.hero-visual{background:linear-gradient(145deg,#e7f2ec,#edf1fb);border-radius:44% 56% 48% 52%/58% 42%;place-items:center;min-height:410px;display:grid;position:relative}.lesson-preview{z-index:2;width:min(350px,78%);box-shadow:var(--shadow);background:#ffffffeb;border:1px solid #fffc;border-radius:24px;padding:30px;position:relative;transform:rotate(-2deg)}.preview-top{color:var(--muted);text-transform:uppercase;letter-spacing:.08em;align-items:center;gap:10px;margin-bottom:22px;font-size:.82rem;font-weight:800;display:flex}.preview-icon{background:var(--sage-soft);color:#477c64;text-transform:none;border-radius:12px;place-items:center;width:38px;height:38px;font-size:1.2rem;display:grid}.lesson-preview h2{color:var(--navy);margin-bottom:10px;font-size:1.55rem}.lesson-preview p{color:var(--muted);line-height:1.6}.progress-track{background:#e9edf1;border-radius:20px;height:9px;margin:24px 0 8px;overflow:hidden}.progress-track span{border-radius:inherit;background:var(--sage);height:100%;display:block}.lesson-preview small{color:var(--muted);font-weight:700}.formula-bubble{z-index:3;color:var(--navy);background:#fff;border-radius:13px;padding:12px 17px;font-weight:800;position:absolute;box-shadow:0 12px 28px #23314d1a}.formula-one{top:48px;left:24px;transform:rotate(-5deg)}.formula-two{bottom:55px;right:12px;transform:rotate(5deg)}.levels-section,.method-section,.page-section{width:min(1180px,100% - 40px);margin:0 auto}.levels-section{border-top:1px solid var(--border);padding:84px 0}.section-heading{justify-content:space-between;align-items:end;gap:40px;margin-bottom:38px;display:flex}.section-heading h2{color:var(--navy);letter-spacing:-.035em;margin:0;font-size:clamp(2rem,4vw,3rem)}.section-heading>p{max-width:480px;color:var(--muted);margin-bottom:6px;line-height:1.6}.section-heading.centered{text-align:center;display:block}.section-heading.centered p{margin:12px auto 0}.level-grid{grid-template-columns:repeat(4,1fr);gap:16px;display:grid}.level-card{border:1px solid var(--border);background:var(--paper);border-radius:21px;flex-direction:column;min-height:300px;padding:25px;display:flex;box-shadow:0 10px 28px #23314d0b}.level-card:hover{box-shadow:var(--shadow);transition:all .2s;transform:translateY(-4px)}.level-card-top{justify-content:space-between;align-items:center;gap:10px;display:flex}.level-badge{color:#fff;background:var(--blue);border-radius:15px;place-items:center;width:50px;height:50px;font-weight:800;display:inline-grid}.chapter-count{color:var(--muted);font-size:.78rem;font-weight:700}.level-card h3{color:var(--navy);margin:25px 0 10px;font-size:1.25rem}.level-card p{color:var(--muted);font-size:.93rem;line-height:1.6}.level-card .text-link{margin-top:auto}.level-6e .level-badge,.level-badge.level-6e{background:var(--sage)}.level-5e .level-badge,.level-badge.level-5e{background:var(--blue)}.level-4e .level-badge,.level-badge.level-4e{background:#9a78c7}.level-3e .level-badge,.level-badge.level-3e{background:var(--coral)}.text-link{color:var(--blue-dark);font-weight:800;text-decoration:none}.text-link:hover{text-decoration:underline}.method-section{padding:84px 0 105px}.method-grid{grid-template-columns:repeat(3,1fr);gap:18px;display:grid}.method-grid article{text-align:center;background:#eef4f0;border-radius:20px;padding:30px}.method-grid article:nth-child(2){background:#edf1fb}.method-grid article:nth-child(3){background:#faf2e4}.method-grid article>span{width:42px;height:42px;color:var(--blue-dark);background:#fff;border-radius:50%;place-items:center;margin:0 auto 18px;font-weight:800;display:grid}.method-grid h3{color:var(--navy);margin-bottom:8px}.method-grid p{color:var(--muted);margin-bottom:0}.page-section{padding:75px 0 100px}.page-section h1{font-size:clamp(2.4rem,5vw,4rem)}.page-intro{align-items:flex-start;gap:22px;margin-bottom:50px;display:flex}.page-intro .level-badge{flex:none;margin-top:3px}.page-intro h1{margin-bottom:14px}.page-intro p,.lead{color:var(--muted);font-size:1.08rem;line-height:1.7}.chapter-grid{grid-template-columns:repeat(2,1fr);gap:16px;display:grid}.chapter-card{border:1px solid var(--border);background:var(--paper);border-radius:18px;padding:27px}.chapter-number{color:var(--sage);letter-spacing:.1em;font-size:.78rem;font-weight:800}.chapter-card h2{color:var(--navy);margin:12px 0 9px;font-size:1.18rem}.chapter-card p{color:var(--muted);line-height:1.55}.button-reset{background:0 0;border:0;padding:0}.button-reset:disabled{color:#929aaa;cursor:not-allowed;text-decoration:none}.back-link{color:var(--blue-dark);margin-top:35px;font-weight:800;text-decoration:none;display:inline-block}.narrow-page{text-align:center;max-width:820px}.empty-state{background:var(--paper);border:1px dashed #c9d5ce;border-radius:22px;margin-top:40px;padding:55px 30px}.empty-state>span{color:var(--sage);margin-bottom:16px;font-size:3rem;display:block}.empty-state h2{color:var(--navy)}.empty-state p{color:var(--muted)}.progress-result-card{border:1px solid var(--border);background:var(--paper);text-align:left;box-shadow:var(--shadow);border-radius:20px;grid-template-columns:auto 1fr auto;align-items:center;gap:20px;margin-top:38px;padding:25px;display:grid}.progress-result-card .eyebrow{margin-bottom:5px}.progress-result-card h2{color:var(--navy);margin-bottom:6px}.progress-result-card p{color:var(--muted);margin:0;font-size:.88rem}.progress-result-card>strong{color:var(--sage);font-size:2rem}.contact-page{grid-template-columns:.85fr 1.15fr;gap:70px;display:grid}.contact-intro>p{color:var(--muted);font-size:1.05rem;line-height:1.7}.contact-note{background:var(--sage-soft);border-radius:16px;margin-top:32px;padding:22px}.contact-note strong{color:#3e715a}.contact-note p{color:#587565;margin:7px 0 0;line-height:1.5}.contact-form{border:1px solid var(--border);background:var(--paper);box-shadow:var(--shadow);border-radius:22px;gap:18px;padding:32px;display:grid}.contact-form label{color:var(--navy);gap:7px;font-size:.9rem;font-weight:800;display:grid}.contact-form input,.contact-form select,.contact-form textarea{width:100%;color:var(--navy);background:#fff;border:1px solid #cfd8d3;border-radius:10px;padding:12px 13px}.contact-form textarea{resize:vertical}.form-message{background:var(--sage-soft);color:#3e715a;border-radius:10px;margin:0;padding:12px;font-size:.9rem}.not-found .button{margin-top:20px}.error-code{color:var(--coral);font-size:5rem;font-weight:800}.site-footer{border-top:1px solid var(--border);background:#f0f4f1}.footer-inner{grid-template-columns:1fr auto;align-items:center;gap:22px 40px;width:min(1180px,100% - 40px);margin:0 auto;padding:42px 0;display:grid}.footer-brand{color:var(--navy);align-items:center;gap:10px;display:flex}.footer-inner p{color:var(--muted);margin:9px 0 0;font-size:.85rem}.footer-links{flex-wrap:wrap;justify-content:flex-end;gap:18px;display:flex}.footer-links a{color:#536077;font-size:.88rem;font-weight:700;text-decoration:none}.footer-links a:hover{color:var(--blue-dark)}.footer-meta{border-top:1px solid var(--border);grid-column:1/-1;padding-top:20px}.breadcrumbs{color:var(--muted);flex-wrap:wrap;gap:8px;margin-bottom:34px;font-size:.88rem;display:flex}.breadcrumbs a{color:var(--blue-dark);font-weight:700;text-decoration:none}.lesson-page{max-width:980px}.lesson-header{justify-content:space-between;align-items:flex-end;gap:35px;margin-bottom:34px;display:flex}.lesson-header h1{max-width:780px;margin-bottom:18px;font-size:clamp(2.4rem,5vw,4.2rem)}.lesson-header p{max-width:680px;color:var(--muted);margin-bottom:0;font-size:1.08rem;line-height:1.65}.lesson-meta{background:var(--blue-soft);color:var(--blue-dark);border-radius:14px;flex:none;gap:9px;padding:17px;font-size:.85rem;font-weight:800;display:grid}.objectives-card{background:var(--sage-soft);border-radius:18px;margin-bottom:22px;padding:24px 28px}.objectives-card strong{color:#3e715a}.objectives-card ul{color:#587565;gap:8px;margin:14px 0 0;padding:0;list-style:none;display:grid}.lesson-block{border:1px solid var(--border);background:var(--paper);border-radius:22px;margin-top:22px;padding:34px}.lesson-block>p{color:var(--muted);font-size:1.02rem;line-height:1.75}.block-heading{align-items:flex-start;gap:17px;margin-bottom:25px;display:flex}.block-heading .eyebrow{margin-bottom:6px}.block-heading h2{color:var(--navy);margin:0;font-size:1.65rem}.block-heading p{color:var(--muted);margin:8px 0 0}.step-icon{background:var(--blue-soft);width:42px;height:42px;color:var(--blue-dark);border-radius:13px;flex:none;place-items:center;font-weight:800;display:grid}.definition-box{border-left:4px solid var(--yellow);background:#fff9eb;border-radius:0 14px 14px 0;margin-top:24px;padding:22px}.definition-box p{color:#6f6449;margin:10px 0 0;line-height:1.65}.math-pill{border-radius:7px;padding:2px 8px;font-weight:800;display:inline-block}.math-pill.positive{color:#356d55;background:#dff0e7}.math-pill.negative{color:#a15340;background:#f9e5df}.rule-grid{grid-template-columns:repeat(3,1fr);gap:14px;display:grid}.rule-grid article{background:#f7f9fb;border-radius:16px;padding:22px}.rule-grid article>span{width:30px;height:30px;color:var(--blue-dark);background:#fff;border-radius:9px;place-items:center;margin-bottom:15px;font-weight:800;display:grid}.rule-grid h3{color:var(--navy);margin-bottom:8px;font-size:1rem}.rule-grid p{min-height:72px;color:var(--muted);margin-bottom:16px;font-size:.9rem;line-height:1.5}.rule-grid code{color:var(--navy);font-size:.94rem;font-weight:800}.worked-examples{grid-template-columns:repeat(2,1fr);gap:15px;display:grid}.worked-examples article{border:1px solid var(--border);border-radius:16px;padding:24px}.worked-examples h3{color:var(--navy);font-size:1.25rem}.worked-examples ol{color:var(--muted);padding-left:22px;line-height:1.7}.example-answer{background:var(--sage-soft);color:#3e715a;border-radius:10px;margin-top:18px;padding:12px 14px}.exercise-list{counter-reset:exercises;grid-template-columns:repeat(2,1fr);gap:12px;padding:0;list-style:none;display:grid}.exercise-list li{counter-increment:exercises;border:1px solid var(--border);min-height:72px;color:var(--navy);border-radius:13px;align-items:center;gap:12px;padding:16px;font-weight:800;display:flex}.exercise-list li:before{content:counter(exercises);background:var(--blue-soft);width:27px;height:27px;color:var(--blue-dark);border-radius:8px;flex:none;place-items:center;font-size:.78rem;display:grid}.answer-line{border-bottom:1px dashed #bdc7c1;flex:1;min-width:40px}.corrections-lock{background:#f7f8fa;border-radius:17px;grid-template-columns:auto 1fr;gap:10px 18px;margin-top:24px;padding:24px;display:grid}.lock-icon{width:43px;height:43px;color:var(--navy);background:#eceff4;border-radius:13px;grid-row:1/3;place-items:center;font-size:1.3rem;display:grid}.corrections-lock .eyebrow{margin-bottom:4px}.corrections-lock h3{color:var(--navy);margin-bottom:5px}.corrections-lock p{color:var(--muted);margin-bottom:0;font-size:.9rem;line-height:1.55}.corrections-lock form{grid-column:2;margin-top:8px}.corrections-lock label{color:var(--navy);margin-bottom:6px;font-size:.82rem;font-weight:800;display:block}.code-row{gap:8px;display:flex}.code-row input{border:1px solid #cfd8d3;border-radius:10px;flex:1;min-width:0;padding:10px 12px}.lock-message{background:#fff4da;border-radius:9px;grid-column:2;padding:10px;color:#75633b!important}.quiz-list{gap:15px;margin-bottom:24px;display:grid}.quiz-question{border:1px solid var(--border);border-radius:16px;margin:0;padding:22px}.quiz-question legend{color:var(--navy);align-items:center;gap:10px;padding:0 8px;font-weight:800;display:flex}.quiz-question legend span{background:var(--blue-soft);width:28px;height:28px;color:var(--blue-dark);border-radius:8px;place-items:center;font-size:.78rem;display:inline-grid}.choice-grid{grid-template-columns:repeat(2,1fr);gap:9px;margin-top:16px;display:grid}.quiz-choice{border:1px solid var(--border);color:#59667b;cursor:pointer;border-radius:11px;align-items:center;gap:10px;padding:12px 14px;display:flex}.quiz-choice:hover,.quiz-choice.selected{background:var(--blue-soft);border-color:#91abe2}.quiz-choice.correct{background:var(--sage-soft);color:#356d55;border-color:#78ae95}.quiz-choice.wrong{color:#9c4f3c;background:#fcedea;border-color:#e7a391}.quiz-choice input{accent-color:var(--blue)}.answer-explanation{color:var(--muted);background:#f7f8fa;border-radius:9px;margin:13px 0 0;padding:11px 13px;font-size:.88rem;line-height:1.5}.quiz-error{color:#a54d39;font-weight:800}.quiz-result{background:var(--sage-soft);border-radius:16px;grid-template-columns:auto 1fr auto;align-items:center;gap:18px;padding:20px;display:grid}.quiz-result>strong{color:#356d55;font-size:2.2rem}.quiz-result h3{color:#356d55;margin-bottom:3px}.quiz-result p{color:#587565;margin-bottom:0;font-size:.88rem}@media (width<=980px){.header-inner{flex-direction:column;align-items:flex-start;gap:10px;min-height:auto;padding:14px 0}.main-nav{width:100%;padding-bottom:3px;overflow-x:auto}.hero-section{grid-template-columns:1fr;gap:44px;padding-top:60px}.hero-copy{text-align:center}.hero-copy>p{margin-inline:auto}.hero-actions,.trust-row{justify-content:center}.hero-visual{width:min(620px,100%);margin:0 auto}.level-grid{grid-template-columns:repeat(2,1fr)}.contact-page{grid-template-columns:1fr;gap:35px}.rule-grid{grid-template-columns:1fr}.rule-grid p{min-height:auto}}@media (width<=650px){.header-inner,.hero-section,.levels-section,.method-section,.page-section,.footer-inner{width:min(100% - 28px,1180px)}.nav-link{padding:8px 9px}.hero-section{padding:45px 0 65px}.hero-copy h1{font-size:2.7rem}.hero-copy>p{font-size:1.05rem}.hero-actions{flex-direction:column}.hero-actions .button{width:100%}.hero-visual{min-height:340px}.lesson-preview{width:84%;padding:24px}.formula-one{top:25px;left:2px}.formula-two{bottom:25px;right:0}.section-heading{display:block}.section-heading>p{margin-top:14px}.level-grid,.method-grid,.chapter-grid{grid-template-columns:1fr}.levels-section,.method-section,.page-section{padding:60px 0}.level-card{min-height:270px}.page-intro{display:block}.page-intro .level-badge{margin-bottom:20px}.contact-form{padding:22px}.footer-inner{grid-template-columns:1fr}.footer-links{justify-content:flex-start}.lesson-header{display:block}.lesson-meta{flex-wrap:wrap;margin-top:20px;display:flex}.lesson-block{padding:23px 18px}.worked-examples,.exercise-list,.choice-grid,.corrections-lock{grid-template-columns:1fr}.lock-icon,.corrections-lock form,.lock-message{grid-area:auto/1}.code-row{flex-direction:column}.quiz-result{text-align:center;grid-template-columns:1fr}.progress-result-card{grid-template-columns:auto 1fr}.progress-result-card>strong{text-align:center;grid-column:1/-1}}@media (prefers-reduced-motion:reduce){html{scroll-behavior:auto}*,:before,:after{transition-duration:.01ms!important;animation-duration:.01ms!important}}.fourth-level .page-intro{margin-bottom:28px}.fourth-level h1{font-size:clamp(2rem,4vw,3.1rem)}.study-start{background:#edf1fb;border-left:5px solid #8460b3;border-radius:20px;grid-template-columns:1fr 220px;gap:32px;padding:30px;display:grid}.study-start h2{margin-bottom:10px}.study-start p{color:#536077}.study-count{align-content:center;gap:10px;display:grid}.study-count>strong{color:#68458f;font-size:2.5rem}.study-count small{font-size:1.1rem}.study-count progress{accent-color:#8460b3;width:100%}.content-counts{flex-wrap:wrap;gap:14px 24px;padding:24px 0;font-size:.94rem;display:flex}.content-counts a{color:var(--blue-dark);margin-left:auto}.course-toolbar{gap:18px;padding:20px 0;display:flex}.course-toolbar label{flex:1;gap:8px;font-weight:700;display:grid}.course-toolbar input,.course-toolbar select,.practice-input input{width:100%;min-width:0;color:var(--navy);background:#fff;border:1px solid #b4c1b9;border-radius:10px;padding:12px}.course-toolbar label:first-child{flex:2}.lesson-directory{margin:18px 0 0;padding:0;list-style:none}.lesson-directory li+li{border-top:1px solid var(--border)}.lesson-directory a{color:var(--navy);border-radius:8px;gap:7px;padding:15px 8px;font-weight:700;text-decoration:none;display:grid}.lesson-directory a:hover{background:var(--blue-soft)}.lesson-directory small{color:#536077;font-size:.875rem;font-weight:400}.lesson-directory small span{float:right}.lesson-jumps{flex-wrap:wrap;gap:10px;margin-bottom:22px;display:flex}.lesson-jumps a{border:1px solid var(--border);color:var(--blue-dark);background:#fff;border-radius:10px;padding:10px 14px;font-weight:700;text-decoration:none}.fourth-lesson h1{font-size:clamp(2rem,4.5vw,3.4rem)}.fourth-lesson h2{line-height:1.3}.course-rules{gap:25px;display:grid}.course-rules>section{gap:16px;display:flex}.course-rules h3{margin-bottom:9px}.course-rules p{color:#536077;margin:0;line-height:1.8}.example-steps{padding-left:24px;line-height:1.8}.example-steps li{margin-bottom:16px;padding-left:6px}.practice-grid{gap:20px;display:grid}.practice-card{border-top:1px solid var(--border);padding-top:24px}.practice-card h3{font-size:1.1rem;line-height:1.6}.practice-card label{margin-bottom:8px;font-size:.94rem;display:block}.practice-input{gap:12px;max-width:560px;display:flex}.practice-feedback{color:var(--blue-dark);margin:14px 0}.fourth-lesson details,.curriculum-note{background:#f2f5f9;border-radius:10px;margin-top:12px;padding:14px 18px}.fourth-lesson summary,.curriculum-note summary{cursor:pointer;padding:4px 0;font-weight:700}.fourth-lesson details p,.curriculum-note p{margin:12px 0 0;line-height:1.75}.correction-toggle{min-height:44px;margin-top:8px}.memo-card{border-top:4px solid #8460b3}.print-button{margin-top:20px}.lesson-bottom{justify-content:space-between;gap:24px;margin-top:32px;line-height:1.6;display:flex}.lesson-bottom a{max-width:50%;color:var(--blue-dark);font-weight:700}.math-lab{background:#f0f4fe}.math-lab svg{width:100%;max-width:480px;margin:auto;display:block}.math-lab svg text{fill:var(--navy);font-size:14px}.lab-layout{grid-template-columns:1fr 1fr;align-items:center;gap:20px;display:grid}.lab-slider{margin:20px 0;display:block}.lab-slider input{accent-color:#68458f;width:100%;min-height:30px;margin:14px 0;display:block}.lab-actions{flex-wrap:wrap;gap:12px;margin-bottom:20px;display:flex}.balance-values{justify-content:center;align-items:center;gap:24px;padding:20px 0;display:flex}.balance-values>div{text-align:center;background:#fff;border-radius:14px;padding:20px}.balance-values strong{font-size:2rem;display:block}.algorithm-code{color:#fff;white-space:pre-wrap;background:#23314d;border-radius:12px;padding:20px;line-height:1.9}.revision-deck{margin-top:32px}.flashcard{text-align:center;background:#edf1fb;border-radius:16px;padding:28px}.flashcard>span{color:#536077;font-size:.9rem}.flashcard h3{margin:18px 0;font-size:1.5rem}.flashcard-answer{text-align:left;margin:22px 0 0;line-height:1.8}.deck-controls{justify-content:space-between;align-items:center;gap:14px;margin-top:18px;display:flex}.curriculum-note{margin-top:28px}.sr-only{clip:rect(0,0,0,0);white-space:nowrap;border:0;width:1px;height:1px;padding:0;position:absolute;overflow:hidden}button:disabled{opacity:.55;cursor:not-allowed}summary:focus-visible{outline-offset:3px;outline:3px solid #4f78d1}[id]{scroll-margin-top:150px}@media (width<=650px){.study-start{grid-template-columns:1fr;padding:24px}.study-count{border-top:1px solid #ccd5e6;padding-top:16px}.course-toolbar,.practice-input,.lesson-bottom{flex-direction:column}.content-counts a{margin-left:0}.lab-layout{grid-template-columns:1fr}.deck-controls{flex-wrap:wrap}.deck-controls a{text-align:center;order:3;width:100%;padding:10px}.lesson-bottom a{max-width:100%}.balance-values{gap:12px}.balance-values>div{padding:14px}.fourth-lesson .lesson-meta{font-size:.875rem}}@media print{.site-header,.site-footer,.skip-link,.fourth-lesson>:not(.lesson-header):not(.memo-card):not(.print-memo),.print-button{display:none!important}.fourth-lesson,.fourth-lesson .memo-card{background:#fff;border:none;width:100%;padding:0}.memo-card details{display:none}.print-memo{display:block!important}.print-memo p{line-height:1.6}.lesson-header h1{font-size:24pt}}.print-memo{display:none}.sixth-level,.sixth-lesson{--blue:#285cc4;--blue-dark:#234fa4;--blue-soft:#edf3ff;--sage-soft:#e6f6f0}.sixth-level{padding-top:42px}.sixth-heading{justify-content:space-between;align-items:center;gap:30px;margin-bottom:24px;display:flex}.sixth-heading h1{letter-spacing:-.035em;margin-bottom:18px;font-size:clamp(2.1rem,4.1vw,3.3rem);line-height:1.1}.sixth-heading h1 em{color:#285cc4;font-style:normal}.sixth-heading p{color:#536077;margin:0;font-size:1.08rem;line-height:1.7}.sixth-progress{text-align:center;background:#fff;border:1px solid #c4d1e6;border-radius:18px;gap:8px;min-width:180px;padding:22px 28px;display:grid}.sixth-progress>strong{color:#285cc4;font-size:2.4rem}.sixth-progress small{color:#536077;font-size:1rem}.sixth-progress progress{accent-color:#285cc4;width:100%}.sixth-progress a{color:#234fa4;font-size:.94rem}.sixth-start{grid-template-columns:1.15fr 1fr;gap:20px;display:grid}.sixth-start article{border-radius:20px;padding:28px}.sixth-mission{background:#eaf1ff;border:1px solid #c5d5f5;border-top:5px solid #285cc4}.sixth-memory{background:#f0ebfc;border:1px solid #dbd0f4;border-top:5px solid #7954b5}.sixth-start h2{margin-bottom:12px;font-size:1.6rem;line-height:1.3}.sixth-start p{color:#536077;line-height:1.7}.sixth-memory .eyebrow{color:#694493}.sixth-road{border-bottom:1px solid var(--border);flex-wrap:wrap;justify-content:space-around;gap:16px;padding:24px 0 34px;display:flex}.sixth-road span{align-items:center;gap:10px;font-weight:700;display:flex}.sixth-road b{color:#285cc4;background:#eaf1ff;border-radius:50%;place-items:center;width:32px;height:32px;display:grid}.sixth-program-heading{justify-content:space-between;align-items:end;gap:20px;margin-top:36px;display:flex}.sixth-program-heading h2{margin-bottom:0;font-size:1.8rem}.sixth-program-heading p{color:#536077;margin-bottom:4px}.sixth-chapters{grid-template-columns:repeat(2,minmax(0,1fr));gap:20px;display:grid}.sixth-chapter{background:#fff;border:1px solid #ced9e8;border-radius:18px;overflow:hidden}.sixth-chapter-title{background:#edf3ff;border-top:4px solid #285cc4;align-items:center;gap:16px;padding:20px;display:flex}.sixth-chapter-title>span{color:#285cc4;background:#fff;border-radius:12px;place-items:center;min-width:52px;height:52px;font-size:1.5rem;font-weight:800;display:grid}.sixth-chapter-title h2{margin:5px 0 0;font-size:1.22rem}.sixth-chapter-title small{color:#536077;font-size:.875rem}.theme-1 .sixth-chapter-title{background:#e8f6f0;border-color:#197964}.theme-1 .sixth-chapter-title>span{color:#197964}.theme-2 .sixth-chapter-title{background:#fff5df;border-color:#99631d}.theme-2 .sixth-chapter-title>span{color:#99631d}.theme-3 .sixth-chapter-title{background:#f1ecfb;border-color:#7651b0}.theme-3 .sixth-chapter-title>span{color:#7651b0}.sixth-chapter ul{margin:0;padding:4px 20px 12px;list-style:none}.sixth-chapter li+li{border-top:1px solid #e0e6ef}.sixth-chapter a{border-radius:8px;gap:7px;padding:17px 8px;font-weight:700;line-height:1.5;text-decoration:none;display:grid}.sixth-chapter a:hover{background:#edf3ff}.sixth-chapter a small{color:#536077;font-size:.875rem;font-weight:400}.sixth-chapter a small b{float:right;color:#285cc4}.sixth-lesson{padding-top:36px}.sixth-lesson .lesson-header{align-items:start}.sixth-lesson .lesson-header h1{font-size:clamp(2rem,4vw,3rem);line-height:1.16}.sixth-lesson .lesson-meta{font-size:.9rem}.sixth-lesson .lesson-block{border-color:#ced9e8;border-radius:18px}.sixth-lesson .course-rules p{font-size:1.08rem;line-height:1.85}.sixth-lesson .course-rules h3{font-size:1.2rem}.sixth-lesson #cours{border-top:5px solid #285cc4}.sixth-lesson #exemple{border-top:5px solid #197964}.sixth-lesson #exercices{border-top:5px solid #99631d}.sixth-lesson .quiz-block{border-top:5px solid #7651b0}.sixth-lesson .button{min-height:50px}.sixth-lab{background:#f0f7ff}.sixth-lab svg{width:100%;max-width:450px;margin:18px auto;display:block}.sixth-lab svg text{fill:#23314d;font-family:inherit;font-size:14px}.lab-select{gap:8px;max-width:300px;font-weight:700;display:grid}.lab-select select{background:#fff;border:1px solid #acbdd3;border-radius:8px;padding:10px}.fraction-bands{gap:18px;display:grid}.fraction-bands small{margin-bottom:6px;font-size:.9rem;display:block}.fraction-strip{border:2px solid #197964;border-radius:8px;display:grid;overflow:hidden}.fraction-strip span{background:#fff;border-right:1px solid #197964;place-items:center;height:52px;display:grid}.fraction-strip span:last-child{border-right:0}.fraction-strip .filled{color:#fff;background:#278d77;font-size:1.2rem}.lab-conclusion{background:#fff;border-radius:12px;margin:22px 0 0;padding:18px;line-height:1.8}.place-table{border:1px solid #afc3df;border-radius:10px;grid-template-columns:repeat(4,minmax(0,1fr));display:grid;overflow:hidden}.place-table>div{text-align:center;background:#fff;border-right:1px solid #afc3df}.place-table>div:last-child{border:none}.place-table span{background:#edf3ff;padding:10px 3px;font-size:.9rem;display:block}.place-table strong{color:#234fa4;padding:18px 0;font-size:2rem;display:block}.area-results{grid-template-columns:1fr 1fr;gap:14px;display:grid}.area-results p{text-align:center;background:#fff;border:1px solid #b5d8ce;border-radius:12px;padding:20px}.area-results span{font-size:.94rem;display:block}.area-results strong{color:#197964;margin:12px 0;font-size:1.8rem;display:block}.area-results p+p{border-color:#cabbeb}.area-results p+p strong{color:#694493}.ratio-table{border-collapse:collapse;background:#fff;width:100%}.ratio-table caption{padding:12px;font-weight:700}.ratio-table th,.ratio-table td{text-align:center;border:1px solid #afc3df;padding:14px 8px}.ratio-table th{background:#edf3ff}.step-track{gap:6px;margin:26px 0;display:flex}.step-track span{background:#fff;border:1px solid #afc3df;border-radius:8px;flex:1;place-items:center;height:44px;display:grid}.step-track .current{color:#fff;background:#285cc4;font-weight:800}.memory-page{max-width:980px;padding-top:42px}.memory-page h1{font-size:clamp(2rem,4vw,3.3rem)}.memory-levels{grid-template-columns:repeat(4,1fr);gap:12px;margin:28px 0;display:grid}.memory-levels a{text-align:center;background:#fff;border:1px solid #b9c8dd;border-radius:12px;gap:5px;padding:15px 8px;font-size:1.3rem;font-weight:800;text-decoration:none;display:grid}.memory-levels span{font-size:.875rem;font-weight:400}.memory-levels .active{color:#fff;background:#285cc4;border-color:#285cc4}.memory-score{flex-wrap:wrap;gap:24px;padding:16px 0 0;display:flex}.memory-score strong{color:#285cc4}.memory-toolbar{align-items:end}.memory-toolbar label:first-child{flex:1}.memory-toolbar .button{flex-shrink:0}.memory-notice{color:#234fa4;min-height:1.4em;margin:0 0 12px}.memory-card{background:#fff;border:1px solid #bacbe3;border-top:5px solid #285cc4;border-radius:20px;padding:28px;box-shadow:0 12px 32px #24467a0a}.memory-card-top{color:#536077;justify-content:space-between;gap:14px;font-size:.9rem;display:flex}.memory-prompt{color:#536077;margin:28px 0 12px;display:block}.memory-card h2{margin-bottom:26px;font-size:clamp(1.35rem,3vw,1.9rem);line-height:1.5}.memory-answer{border-top:1px solid #d5dfea;margin-top:24px;padding:24px 0 0}.memory-answer>p{font-size:1.1rem;line-height:1.85}.memory-answer .memory-question{margin-top:24px;font-size:1rem}.memory-rating{flex-wrap:wrap;gap:14px;display:flex}.memory-existing{border-top:1px solid #d5dfea;justify-content:space-between;gap:16px;margin-top:20px;padding-top:20px;font-size:.9rem;display:flex}.memory-existing button{min-height:44px}.memory-footnote{color:#536077;margin:24px 0 0;font-size:.9rem;line-height:1.7}.level-memory-banner{background:#edf3ff;border-radius:18px;justify-content:space-between;align-items:center;gap:24px;margin-bottom:24px;padding:26px;display:flex}.level-memory-banner h2{margin-bottom:10px}.level-memory-banner p{margin-bottom:0;line-height:1.6}.level-memory-banner .button{flex-shrink:0}@media (width<=980px){.memory-toolbar{flex-wrap:wrap}.memory-toolbar label{min-width:200px}}@media (width<=650px){.sixth-level,.memory-page{padding-top:28px}.sixth-heading{flex-wrap:wrap;align-items:start;gap:16px}.sixth-progress{flex-wrap:wrap;align-items:center;gap:14px;width:100%;padding:14px;display:flex}.sixth-progress>strong{font-size:1.6rem}.sixth-progress progress{width:90px}.sixth-progress a{margin-left:auto}.sixth-start,.sixth-chapters{grid-template-columns:1fr}.sixth-start article{padding:22px}.sixth-road{justify-content:flex-start;gap:12px}.sixth-program-heading{display:block}.sixth-program-heading p{margin-top:12px;line-height:1.6}.sixth-chapter-title{padding:18px}.memory-card{padding:20px}.memory-toolbar{align-items:stretch}.memory-toolbar label{min-width:0}.memory-levels{gap:8px}.memory-levels span{font-size:.875rem}.memory-existing,.level-memory-banner{flex-direction:column;align-items:start}.memory-deck .deck-controls>span{display:none}.place-table span{overflow-wrap:anywhere;font-size:.875rem}.step-track{gap:3px}.step-track span{min-width:0;height:38px}.area-results{grid-template-columns:1fr}.area-results p{margin:0}.sixth-lesson .course-rules>section{gap:12px}.sixth-lesson .course-rules .step-icon{width:32px;height:32px}.sixth-lesson .course-rules p{font-size:1rem}}.memory-flip-stage{perspective:1400px;margin-top:14px}.memory-flip{color:#23314d;width:100%;font:inherit;text-align:center;cursor:pointer;transform-style:preserve-3d;-webkit-tap-highlight-color:transparent;background:0 0;border:0;border-radius:24px;padding:0;transition:transform .48s cubic-bezier(.2,.7,.2,1);display:grid}.memory-flip.is-flipped{transform:rotateY(180deg)}.memory-flip:focus-visible{outline-offset:6px;outline:3px solid #285cc4}.memory-face{backface-visibility:hidden;overflow-wrap:anywhere;border:1px solid #bacbe3;border-radius:24px;flex-direction:column;grid-area:1/1;justify-content:center;align-items:center;gap:22px;min-height:320px;padding:32px;display:flex;box-shadow:0 12px 28px #24467a12}.memory-front{background:linear-gradient(145deg,#f4f7ff,#e7efff);border-top:5px solid #285cc4}.memory-back{background:linear-gradient(145deg,#f4fcf8,#e0f3ec);border-top:5px solid #197964;transform:rotateY(180deg)}.memory-face-label{letter-spacing:.09em;color:#285cc4;font-size:.78rem;font-weight:800}.memory-back .memory-face-label{color:#17624f}.memory-flip-question{max-width:650px;font-size:clamp(1.4rem,3vw,2rem);font-weight:800;line-height:1.45}.memory-flip-answer{max-width:680px;font-size:clamp(1.05rem,2vw,1.25rem);line-height:1.8}.memory-flip-hint{color:#536077;font-size:.95rem}.memory-flip-action{background:#fff;border:1px solid #c7d4e6;border-radius:30px;padding:12px 18px;font-size:.94rem;font-weight:700}.memory-review-panel{text-align:center;padding:18px 0 4px}.memory-review-panel>p{color:#536077;margin:0 0 12px}.memory-review-panel .memory-rating{grid-template-columns:1fr 1fr;max-width:520px;margin:auto;display:grid}.memory-rating .button{min-height:50px;transition:background .18s,transform .18s}.memory-rating .button:active:not(:disabled){transform:scale(.97)}.memory-rating .button:disabled{opacity:.45;cursor:not-allowed}.memory-course-link{padding:14px 0 0;display:inline-block}.memory-deck .deck-controls{gap:12px}.memory-deck .deck-controls>span{color:#536077;text-align:center;font-size:.8rem}@media (width<=650px){.memory-face{gap:18px;min-height:330px;padding:24px 18px}.memory-card-top{font-size:.82rem}.memory-deck .deck-controls .button{flex:1;padding:12px 8px}.memory-review-panel .memory-rating{gap:10px}}@media (prefers-reduced-motion:reduce){.memory-flip,.memory-rating .button{transition:none}}