:root{--bg:#f7f4ef;--card:#fff;--border:#e2ddd6;--text:#1a1815;--muted:#7a756e;--blue:#1a5fa8;--blue-l:#eaf2fc;--green:#1e6b3c;--green-l:#e8f5ee;--amber:#8a4f00;--amber-l:#fef3e2;--red:#9b2020;--red-l:#fdecec;--accent:#d4500a}*,:before,:after{box-sizing:border-box;margin:0;padding:0}html{scroll-behavior:smooth}body{background:var(--bg);color:var(--text);min-height:100vh;font-family:DM Sans,sans-serif}a{color:inherit;text-decoration:none}.home-hero{background:var(--text);color:#fff;text-align:center;padding:5rem 2rem 4rem;position:relative;overflow:hidden}.home-hero:before{content:"";background:repeating-linear-gradient(45deg,#0000,#0000 40px,#ffffff05 40px 41px);position:absolute;inset:0}.home-hero-tag{letter-spacing:2px;text-transform:uppercase;color:#ffffffb3;border:1px solid #ffffff4d;border-radius:20px;margin-bottom:1.5rem;padding:4px 14px;font-family:DM Mono,monospace;font-size:11px;display:inline-block;position:relative}.home-hero h1{letter-spacing:-1px;margin-bottom:1rem;font-family:DM Serif Display,serif;font-size:clamp(2.8rem,8vw,5rem);line-height:1.05;position:relative}.home-hero h1 em{color:#f5a855;font-style:italic}.home-hero p{color:#fff9;max-width:520px;margin:0 auto;font-size:1.05rem;line-height:1.7;position:relative}.home-main{max-width:800px;margin:0 auto;padding:3rem 1.5rem 5rem}.home-section-title{letter-spacing:-.5px;margin-bottom:1.5rem;font-family:DM Serif Display,serif;font-size:1.5rem}.tutorial-grid{flex-direction:column;gap:1rem;display:flex}.tutorial-card{background:var(--card);border:1px solid var(--border);cursor:pointer;border-radius:14px;align-items:center;gap:1.25rem;padding:1.5rem;transition:border-color .2s,box-shadow .2s;display:flex}.tutorial-card:hover{border-color:var(--blue);box-shadow:0 4px 20px #1a5fa814}.tutorial-icon{background:var(--blue-l);width:56px;height:56px;color:var(--blue);border-radius:14px;flex-shrink:0;justify-content:center;align-items:center;font-family:DM Serif Display,serif;font-size:1.6rem;display:flex}.tutorial-card:nth-child(2) .tutorial-icon{background:var(--green-l);color:var(--green);font-family:DM Mono,monospace;font-size:.85rem;font-weight:500}.tutorial-info{flex:1}.home-badge{letter-spacing:2px;text-transform:uppercase;border-radius:20px;margin-bottom:6px;padding:3px 10px;font-family:DM Mono,monospace;font-size:10px;display:inline-block}.home-badge.b-blue{color:var(--blue);background:var(--blue-l)}.home-badge.b-green{color:var(--green);background:var(--green-l)}.tutorial-info h3{letter-spacing:-.3px;margin-bottom:4px;font-family:DM Serif Display,serif;font-size:1.25rem}.tutorial-info p{color:var(--muted);font-size:.875rem;line-height:1.5}.tutorial-arrow{color:var(--muted);flex-shrink:0;font-size:1.25rem;transition:color .2s,transform .2s}.tutorial-card:hover .tutorial-arrow{color:var(--blue);transform:translate(4px)}.home-footer{text-align:center;color:var(--muted);border-top:1px solid var(--border);margin-top:auto;padding:2.5rem 1.5rem}.footer-heart{background:var(--red-l);border-radius:50%;justify-content:center;align-items:center;width:40px;height:40px;margin-bottom:.75rem;animation:2s ease-in-out infinite heartbeat;display:inline-flex}@keyframes heartbeat{0%,to{transform:scale(1)}14%{transform:scale(1.15)}28%{transform:scale(1)}42%{transform:scale(1.1)}56%{transform:scale(1)}}.footer-msg{color:var(--text);margin-bottom:4px;font-family:DM Serif Display,serif;font-size:1rem}.footer-sub{color:var(--muted);font-size:.8rem;font-style:italic}@media (width<=600px){.home-hero{padding:3.5rem 1.25rem 3rem}.home-hero p{font-size:.95rem}.home-main{padding:2rem 1rem 3rem}.tutorial-card{gap:1rem;padding:1.15rem}.tutorial-icon{border-radius:12px;width:46px;height:46px;font-size:1.3rem}.tutorial-info h3{font-size:1.1rem}.tutorial-info p{font-size:.8rem}}.hero{background:var(--text);color:#fff;text-align:center;padding:4rem 2rem 3rem;position:relative;overflow:hidden}.hero:before{content:"";background:repeating-linear-gradient(45deg,#0000,#0000 40px,#ffffff05 40px 41px);position:absolute;inset:0}.hero-tag{letter-spacing:2px;text-transform:uppercase;color:#ffffffb3;border:1px solid #ffffff4d;border-radius:20px;margin-bottom:1.5rem;padding:4px 14px;font-family:DM Mono,monospace;font-size:11px;display:inline-block;position:relative}.hero-back{color:#ffffff80;z-index:1;font-family:DM Sans,sans-serif;font-size:14px;text-decoration:none;transition:color .2s;position:absolute;top:1.5rem;left:1.5rem}.hero-back:hover{color:#fff}.hero h1{letter-spacing:-1px;margin-bottom:1rem;font-family:DM Serif Display,serif;font-size:clamp(2.6rem,8vw,4.8rem);line-height:1.05;position:relative}.hero h1 em{color:#f5a855;font-style:italic}.hero p{color:#fff9;max-width:520px;margin:0 auto 2.5rem;font-size:1.05rem;line-height:1.7;position:relative}.progress-bar{flex-wrap:wrap;justify-content:center;gap:6px;display:flex;position:relative}.prog-dot{cursor:pointer;background:#fff3;border-radius:2px;width:30px;height:4px;transition:background .3s}.prog-dot.active{background:#f5a855}.prog-dot.done{background:#ffffff73}.nav-desktop{z-index:100;-webkit-backdrop-filter:blur(12px);backdrop-filter:blur(12px);border-bottom:1px solid var(--border);scrollbar-width:none;background:#f7f4eff0;align-items:center;gap:0;padding:0 1rem;display:flex;position:sticky;top:0;overflow-x:auto}.nav-desktop::-webkit-scrollbar{display:none}.nav-btn{color:var(--muted);cursor:pointer;white-space:nowrap;background:0 0;border:none;border-bottom:2px solid #0000;padding:13px;font-family:DM Sans,sans-serif;font-size:12.5px;font-weight:500;transition:color .2s,border-color .2s}.nav-btn:hover{color:var(--text)}.nav-btn.active{color:var(--blue);border-bottom-color:var(--blue)}.nav-mobile{z-index:100;display:none;position:sticky;top:0}.nav-mobile-toggle{-webkit-backdrop-filter:blur(12px);backdrop-filter:blur(12px);border:none;border-bottom:1px solid var(--border);cursor:pointer;background:#f7f4eff5;align-items:center;gap:10px;width:100%;padding:12px 16px;font-family:DM Sans,sans-serif;display:flex}.nav-mobile-step{color:#fff;background:var(--blue);border-radius:10px;flex-shrink:0;padding:2px 8px;font-family:DM Mono,monospace;font-size:11px;font-weight:500}.nav-mobile-label{color:var(--text);text-align:left;flex:1;font-size:14px;font-weight:500}.nav-mobile-chevron{color:var(--muted);flex-shrink:0;transition:transform .25s}.nav-mobile-chevron.open{transform:rotate(180deg)}.nav-mobile-backdrop{z-index:99;background:#0003;position:fixed;inset:0}.nav-mobile-dropdown{background:var(--card);border-bottom:1px solid var(--border);z-index:100;flex-direction:column;max-height:0;transition:max-height .3s;display:flex;position:absolute;top:100%;left:0;right:0;overflow:hidden;box-shadow:0 8px 30px #0000001a}.nav-mobile-dropdown.open{max-height:500px}.nav-mobile-item{color:var(--muted);border:none;border-bottom:1px solid var(--border);cursor:pointer;text-align:left;background:0 0;align-items:center;gap:12px;padding:13px 16px;font-family:DM Sans,sans-serif;font-size:14px;transition:background .15s;display:flex}.nav-mobile-item:last-child{border-bottom:none}.nav-mobile-item:hover{background:var(--bg)}.nav-mobile-item.active{color:var(--blue);background:var(--blue-l);font-weight:500}.nav-mobile-item-num{background:var(--bg);width:24px;height:24px;color:var(--muted);border-radius:50%;flex-shrink:0;justify-content:center;align-items:center;font-family:DM Mono,monospace;font-size:12px;font-weight:600;display:flex}.nav-mobile-item.active .nav-mobile-item-num{background:var(--blue);color:#fff}.nav-mobile-check{color:var(--blue);margin-left:auto;font-size:14px}@media (width<=700px){.nav-desktop{display:none}.nav-mobile{display:block}}.lim-main{max-width:800px;margin:0 auto;padding:3rem 1.5rem 5rem}.section{animation:.4s fadeUp;display:none}.section.visible{display:block}@keyframes fadeUp{0%{opacity:0;transform:translateY(14px)}to{opacity:1;transform:translateY(0)}}.sec-hdr{margin-bottom:2rem}.badge{letter-spacing:2px;text-transform:uppercase;border-radius:20px;margin-bottom:10px;padding:3px 10px;font-family:DM Mono,monospace;font-size:10px;display:inline-block}.b-blue{color:var(--blue);background:var(--blue-l)}.b-green{color:var(--green);background:var(--green-l)}.b-amber{color:var(--amber);background:var(--amber-l)}.b-red{color:var(--red);background:var(--red-l)}.b-dark{color:#fff;background:var(--text)}.b-gray{color:var(--muted);background:var(--bg);border:1px solid var(--border)}.lim-main h2{letter-spacing:-.5px;margin-bottom:.4rem;font-family:DM Serif Display,serif;font-size:2rem;line-height:1.15}.subtitle{color:var(--muted);font-size:1rem;line-height:1.6}.card{background:var(--card);border:1px solid var(--border);border-radius:14px;margin-bottom:1.25rem;padding:1.5rem}.g2{grid-template-columns:1fr 1fr;gap:1rem;margin-bottom:1.25rem;display:grid}@media (width<=540px){.g2{grid-template-columns:1fr}}.ci{background:var(--card);border:1px solid var(--border);border-radius:14px;padding:1.25rem}.analogy{border-left:3px solid var(--accent);background:#fff8f4;border-radius:0 12px 12px 0;margin:1.1rem 0;padding:1.25rem 1.5rem}.a-lbl{letter-spacing:2px;text-transform:uppercase;color:var(--accent);margin-bottom:6px;font-size:10px;font-weight:600}.analogy p{color:var(--text);font-size:.95rem;line-height:1.7}.def-box{background:var(--text);color:#fff;border-radius:14px;margin:1.5rem 0;padding:1.75rem;position:relative;overflow:hidden}.def-box:before{content:"";background:#ffffff0a;border-radius:50%;width:120px;height:120px;position:absolute;top:-30px;right:-30px}.def-tag{letter-spacing:2px;text-transform:uppercase;color:#f5a855;margin-bottom:12px;font-family:DM Mono,monospace;font-size:10px}.def-main{margin-bottom:12px;font-family:DM Serif Display,serif;font-size:1.25rem;line-height:1.5}.def-sub{color:#ffffff8c;font-size:.875rem;line-height:1.7}.math{text-align:center;background:var(--blue-l);color:var(--blue);border-radius:10px;margin:.8rem 0;padding:.85rem 1rem;font-family:DM Mono,monospace;font-size:1.1rem;font-weight:500}.math.g{background:var(--green-l);color:var(--green)}.math.a{background:var(--amber-l);color:var(--amber)}.math.r{background:var(--red-l);color:var(--red)}.math.sm{padding:.65rem .9rem;font-size:1rem}.tbl-wrap{margin:.8rem 0;overflow-x:auto}table{border-collapse:collapse;width:100%;font-size:14px}th{background:var(--bg);color:var(--muted);text-align:center;border:1px solid var(--border);padding:9px 12px;font-size:12px;font-weight:500}td{text-align:center;border:1px solid var(--border);color:var(--text);padding:8px 12px;font-family:DM Mono,monospace;font-size:13px}tr.hl td{color:var(--blue);background:var(--blue-l);font-weight:600}tr.hl-r td{color:var(--red);background:var(--red-l);font-weight:600}tr:hover:not(.hl):not(.hl-r) td{background:var(--bg)}canvas{border:1px solid var(--border);background:#fff;border-radius:10px;width:100%;margin-top:.8rem;display:block}.ctrl{align-items:center;gap:12px;margin:.6rem 0;display:flex}.ctrl label{color:var(--muted);min-width:110px;font-size:13px}.ctrl input[type=range]{appearance:none;background:var(--border);border-radius:2px;outline:none;flex:1;height:4px}.ctrl input[type=range]::-webkit-slider-thumb{appearance:none;background:var(--blue);cursor:pointer;border:2px solid #fff;border-radius:50%;width:18px;height:18px;box-shadow:0 1px 4px #00000026}.rbox{background:var(--blue-l);text-align:center;border-radius:12px;margin:.8rem 0;padding:.85rem}.rval{color:var(--blue);font-family:DM Serif Display,serif;font-size:2.4rem}.rlbl{color:var(--muted);margin-top:2px;font-family:DM Mono,monospace;font-size:12px}.step-list{list-style:none}.step-item{border-bottom:1px solid var(--border);align-items:flex-start;gap:14px;padding:1.1rem 0;display:flex}.step-item:last-child{border-bottom:none}.snum{background:var(--blue);color:#fff;border-radius:50%;flex-shrink:0;justify-content:center;align-items:center;width:30px;height:30px;margin-top:2px;font-size:13px;font-weight:600;display:flex}.scontent h4{margin-bottom:4px;font-weight:600}.scontent p{color:var(--muted);font-size:14px;line-height:1.6}.tipo{border:1px solid var(--border);border-radius:12px;margin-bottom:1rem;padding:1.2rem}.tipo h4{margin-bottom:4px;font-size:13px;font-weight:600}.tipo p{color:var(--muted);margin-top:6px;font-size:13px;line-height:1.6}.quiz-q{margin-bottom:.85rem;font-size:1.05rem;font-weight:500;line-height:1.5}.quiz-opts{flex-direction:column;gap:7px;display:flex}.qopt{text-align:left;border:1.5px solid var(--border);background:var(--card);width:100%;color:var(--text);cursor:pointer;border-radius:10px;align-items:center;gap:10px;padding:11px 16px;font-family:DM Sans,sans-serif;font-size:14px;transition:border-color .15s,background .15s;display:flex}.qopt:hover:not(:disabled){border-color:var(--blue);background:var(--blue-l)}.qopt.correct{background:var(--green-l);border-color:var(--green);color:var(--green)}.qopt.wrong{background:var(--red-l);border-color:var(--red);color:var(--red)}.qopt .ic{text-align:center;flex-shrink:0;width:20px;font-style:normal}.feedback{border-radius:10px;margin-top:11px;padding:10px 14px;font-size:13.5px;line-height:1.6;display:none}.feedback.ok{background:var(--green-l);color:var(--green);display:block}.feedback.bad{background:var(--red-l);color:var(--red);display:block}.quiz-score{text-align:center;background:var(--blue-l);border-radius:14px;margin-top:1.5rem;padding:2.5rem 2rem;display:none}.quiz-score.show{display:block}.score-num{color:var(--blue);font-family:DM Serif Display,serif;font-size:3rem}.bot-nav{justify-content:space-between;gap:12px;margin-top:3rem;display:flex}.btn-nav{cursor:pointer;border:1.5px solid var(--border);border-radius:10px;padding:12px 24px;font-family:DM Sans,sans-serif;font-size:14px;font-weight:500;transition:all .2s}.btn-prev{background:var(--card);color:var(--muted)}.btn-prev:hover{border-color:var(--text);color:var(--text)}.btn-next{background:var(--blue);color:#fff;border-color:var(--blue);margin-left:auto}.btn-next:hover{background:#1450a0}code{background:var(--bg);border:1px solid var(--border);border-radius:4px;padding:2px 6px;font-family:DM Mono,monospace;font-size:.88em}.callout{border-radius:12px;margin:.8rem 0;padding:.9rem 1.1rem;font-size:14px;line-height:1.7}.cl-blue{background:var(--blue-l);color:var(--blue)}.cl-amber{background:var(--amber-l);color:var(--amber)}.cl-green{background:var(--green-l);color:var(--green)}.cl-red{background:var(--red-l);color:var(--red)}.timeline{padding-left:28px;position:relative}.timeline:before{content:"";background:var(--border);width:2px;position:absolute;top:8px;bottom:8px;left:7px}.tl-item{padding-bottom:2rem;position:relative}.tl-item:last-child{padding-bottom:0}.tl-dot{background:var(--card);border:2.5px solid var(--border);z-index:1;border-radius:50%;width:16px;height:16px;position:absolute;top:6px;left:-28px}.tl-dot-accent{border-color:var(--accent);background:var(--accent);box-shadow:0 0 0 4px #d4500a26}.tl-content{padding-left:6px}.tl-year{color:var(--accent);letter-spacing:1px;margin-bottom:8px;font-family:DM Mono,monospace;font-size:12px;font-weight:500}.tl-card{background:var(--card);border:1px solid var(--border);border-radius:14px;align-items:flex-start;gap:1.25rem;padding:1.25rem;display:flex}.tl-card-highlight{border-color:var(--accent);box-shadow:0 2px 16px #d4500a0f}.tl-portrait{background:var(--bg);border:1px solid var(--border);border-radius:10px;flex-shrink:0;width:90px;height:110px;overflow:hidden}.tl-portrait img{object-fit:cover;width:100%;height:100%;display:block}.tl-info{flex:1;min-width:0}.tl-info h3{letter-spacing:-.3px;margin-bottom:2px;font-family:DM Serif Display,serif;font-size:1.1rem}.tl-loc{color:var(--muted);font-family:DM Mono,monospace;font-size:12px}.tl-info p{color:var(--text);margin-top:8px;font-size:14px;line-height:1.7}@media (width<=700px){.hero{padding:3rem 1.25rem 2.25rem}.hero-back{font-size:13px;top:1rem;left:1rem}.hero h1{font-size:clamp(2rem,10vw,2.8rem)}.hero p{margin-bottom:2rem;font-size:.9rem}.lim-main{padding:2rem 1rem 3.5rem}.lim-main h2{font-size:1.6rem}.subtitle{font-size:.9rem}.card{border-radius:12px;padding:1.15rem}.def-box{padding:1.25rem}.def-main{font-size:1.05rem}.math{word-break:break-word;padding:.7rem .75rem;font-size:.9rem}.math.sm{padding:.55rem .7rem;font-size:.85rem}.analogy{padding:1rem 1.15rem}.analogy p{font-size:.88rem}.callout{padding:.75rem .9rem;font-size:13px}th{padding:7px 6px;font-size:11px}td{padding:6px 5px;font-size:11px}.ctrl{flex-wrap:wrap}.ctrl label{min-width:auto;font-size:12px}.rval{font-size:2rem}.step-item{gap:10px;padding:.85rem 0}.scontent p{font-size:13px}.tipo{padding:1rem}.quiz-q{font-size:.95rem}.qopt{padding:10px 12px;font-size:13px}.feedback{padding:8px 12px;font-size:12.5px}.quiz-score{padding:2rem 1.25rem}.score-num{font-size:2.5rem}.bot-nav{gap:8px;margin-top:2rem}.btn-nav{padding:10px 16px;font-size:13px}.ci{padding:1rem}.timeline{padding-left:22px}.timeline:before{left:5px}.tl-dot{width:12px;height:12px;top:8px;left:-22px}.tl-card{flex-direction:column;gap:.85rem;padding:1rem}.tl-portrait{border-radius:8px;width:70px;height:85px}.tl-info h3{font-size:1rem}.tl-info p{font-size:13px}.tl-item{padding-bottom:1.5rem}}@media (width<=380px){.hero h1{font-size:1.8rem}.lim-main h2{font-size:1.35rem}.lim-main{padding:1.5rem .75rem 3rem}.card{padding:1rem}.bot-nav{flex-direction:column}.btn-next{margin-left:0}}.ej-hero{background:var(--text);color:#fff;text-align:center;padding:4rem 2rem 3rem;position:relative;overflow:hidden}.ej-hero:before{content:"";background:repeating-linear-gradient(45deg,#0000,#0000 40px,#ffffff05 40px 41px);position:absolute;inset:0}.ej-hero-back{color:#ffffff80;z-index:1;font-family:DM Sans,sans-serif;font-size:14px;text-decoration:none;transition:color .2s;position:absolute;top:1.5rem;left:1.5rem}.ej-hero-back:hover{color:#fff}.ej-hero-tag{letter-spacing:2px;text-transform:uppercase;color:#ffffffb3;border:1px solid #ffffff4d;border-radius:20px;margin-bottom:1.5rem;padding:4px 14px;font-family:DM Mono,monospace;font-size:11px;display:inline-block;position:relative}.ej-hero h1{letter-spacing:-1px;margin-bottom:1rem;font-family:DM Serif Display,serif;font-size:clamp(2.2rem,7vw,4rem);line-height:1.1;position:relative}.ej-hero h1 em{color:#f5a855;font-style:italic}.ej-hero p{color:#fff9;max-width:560px;margin:0 auto;font-size:1rem;line-height:1.7;position:relative}.ej-stats{justify-content:center;gap:2rem;margin-top:2rem;display:flex;position:relative}.ej-stat{text-align:center}.ej-stat-num{color:#f5a855;font-family:DM Serif Display,serif;font-size:2rem;display:block}.ej-stat-lbl{color:#ffffff80;letter-spacing:1px;text-transform:uppercase;font-family:DM Mono,monospace;font-size:11px}.ej-nav-desktop{z-index:100;-webkit-backdrop-filter:blur(12px);backdrop-filter:blur(12px);border-bottom:1px solid var(--border);scrollbar-width:none;background:#f7f4eff0;align-items:center;gap:0;padding:0 .75rem;display:flex;position:sticky;top:0;overflow-x:auto}.ej-nav-desktop::-webkit-scrollbar{display:none}.ej-nav-btn{color:var(--muted);cursor:pointer;white-space:nowrap;background:0 0;border:none;border-bottom:2px solid #0000;align-items:center;gap:6px;padding:13px 12px;font-family:DM Sans,sans-serif;font-size:12.5px;font-weight:500;transition:color .2s,border-color .2s;display:flex}.ej-nav-btn:hover{color:var(--text);border-bottom-color:var(--border)}.ej-nav-num{background:var(--bg);width:18px;height:18px;color:var(--muted);border-radius:50%;flex-shrink:0;justify-content:center;align-items:center;font-family:DM Mono,monospace;font-size:10px;font-weight:600;display:flex}.ej-nav-count{color:var(--muted);opacity:.6;font-family:DM Mono,monospace;font-size:10px}.ej-nav-mobile{z-index:100;display:none;position:sticky;top:0}.ej-nav-mobile-toggle{-webkit-backdrop-filter:blur(12px);backdrop-filter:blur(12px);border:none;border-bottom:1px solid var(--border);cursor:pointer;background:#f7f4eff5;align-items:center;gap:10px;width:100%;padding:12px 16px;font-family:DM Sans,sans-serif;display:flex}.ej-nav-mobile-badge{color:#fff;background:var(--green);border-radius:10px;flex-shrink:0;padding:2px 8px;font-family:DM Mono,monospace;font-size:11px;font-weight:500}.ej-nav-mobile-label{color:var(--text);text-align:left;flex:1;font-size:14px;font-weight:500}.ej-nav-mobile-chevron{color:var(--muted);flex-shrink:0;transition:transform .25s}.ej-nav-mobile-chevron.open{transform:rotate(180deg)}.ej-nav-mobile-backdrop{z-index:99;background:#0003;position:fixed;inset:0}.ej-nav-mobile-dropdown{background:var(--card);border-bottom:1px solid var(--border);z-index:100;flex-direction:column;max-height:0;transition:max-height .3s;display:flex;position:absolute;top:100%;left:0;right:0;overflow:hidden;box-shadow:0 8px 30px #0000001a}.ej-nav-mobile-dropdown.open{max-height:600px}.ej-nav-mobile-item{color:var(--text);border:none;border-bottom:1px solid var(--border);cursor:pointer;text-align:left;background:0 0;align-items:center;gap:12px;padding:12px 16px;font-family:DM Sans,sans-serif;font-size:14px;transition:background .15s;display:flex}.ej-nav-mobile-item:last-child{border-bottom:none}.ej-nav-mobile-item:hover{background:var(--bg)}.ej-nav-mobile-item-num{color:#fff;border-radius:50%;flex-shrink:0;justify-content:center;align-items:center;width:24px;height:24px;font-family:DM Mono,monospace;font-size:12px;font-weight:600;display:flex}.ej-nav-mobile-item-text{flex-direction:column;gap:1px;display:flex}.ej-nav-mobile-item-text strong{font-size:14px;font-weight:500}.ej-nav-mobile-item-text small{color:var(--muted);font-family:DM Mono,monospace;font-size:11px}@media (width<=700px){.ej-nav-desktop{display:none}.ej-nav-mobile{display:block}}.ej-main{max-width:820px;margin:0 auto;padding:2rem 1.5rem 5rem}.ej-sec{margin-bottom:2.5rem}.ej-sec-hdr{border-bottom:2px solid var(--border);align-items:center;gap:14px;margin-bottom:1.25rem;padding-bottom:1rem;display:flex}.ej-sec-num{color:#fff;border-radius:50%;flex-shrink:0;justify-content:center;align-items:center;width:38px;height:38px;font-family:DM Serif Display,serif;font-size:1.1rem;display:flex}.ej-sec-hdr h2{letter-spacing:-.3px;margin:0;font-family:DM Serif Display,serif;font-size:1.4rem;line-height:1.2}.ej-sec-hdr p{color:var(--muted);margin-top:2px;font-size:13px}.ej-sec-tip{border-radius:12px;margin-bottom:1.25rem;padding:.85rem 1.1rem;font-size:13px;line-height:1.6}.ej-card{background:var(--card);border:1px solid var(--border);border-radius:14px;margin-bottom:1rem;transition:border-color .2s;overflow:hidden}.ej-card.solved{border-color:var(--green)}.ej-card-top{align-items:flex-start;gap:12px;padding:1.25rem 1.25rem 1rem;display:flex}.ej-num{color:var(--muted);background:var(--bg);border-radius:6px;flex-shrink:0;margin-top:2px;padding:3px 8px;font-family:DM Mono,monospace;font-size:11px;font-weight:600}.ej-card.solved .ej-num{background:var(--green-l);color:var(--green)}.ej-statement{flex:1}.ej-statement .ej-formula{color:var(--text);margin-bottom:4px;font-family:DM Mono,monospace;font-size:1.15rem;font-weight:500;line-height:1.5}.ej-statement .ej-hint{color:var(--muted);font-size:12.5px;line-height:1.5}.ej-diff{flex-shrink:0;gap:3px;margin-top:5px;display:flex}.ej-diff-dot{background:var(--border);border-radius:50%;width:6px;height:6px}.ej-diff-dot.on{background:var(--amber)}.ej-toggle{border:none;border-top:1px solid var(--border);background:var(--bg);width:100%;color:var(--blue);cursor:pointer;justify-content:center;align-items:center;gap:6px;padding:10px 1.25rem;font-family:DM Sans,sans-serif;font-size:13px;font-weight:500;transition:background .15s;display:flex}.ej-toggle:hover{background:var(--blue-l)}.ej-toggle svg{transition:transform .25s}.ej-toggle.open svg{transform:rotate(180deg)}.ej-card.solved .ej-toggle{color:var(--green)}.ej-card.solved .ej-toggle:hover{background:var(--green-l)}.ej-solution{max-height:0;transition:max-height .4s;overflow:hidden}.ej-solution.open{max-height:2000px}.ej-sol-inner{border-top:1px solid var(--border);padding:0 1.25rem 1.25rem}.ej-step{align-items:flex-start;gap:10px;padding:10px 0;display:flex}.ej-step:not(:last-child){border-bottom:1px solid #0000000a}.ej-step-num{background:var(--blue-l);width:22px;height:22px;color:var(--blue);border-radius:50%;flex-shrink:0;justify-content:center;align-items:center;margin-top:1px;font-family:DM Mono,monospace;font-size:11px;font-weight:600;display:flex}.ej-step p{color:var(--text);flex:1;font-size:13.5px;line-height:1.65}.ej-step code{background:var(--bg);border:1px solid var(--border);border-radius:4px;padding:1px 5px;font-family:DM Mono,monospace;font-size:.88em}.ej-result{text-align:center;border-radius:10px;margin-top:10px;padding:10px 14px;font-family:DM Mono,monospace;font-size:1.05rem;font-weight:500}.ej-result-ok{background:var(--green-l);color:var(--green)}.ej-footer{text-align:center;color:var(--muted);border-top:1px solid var(--border);margin-top:2rem;padding:2.5rem 1.5rem}.ej-footer-heart{background:var(--red-l);border-radius:50%;justify-content:center;align-items:center;width:40px;height:40px;margin-bottom:.75rem;animation:2s ease-in-out infinite ej-heartbeat;display:inline-flex}@keyframes ej-heartbeat{0%,to{transform:scale(1)}14%{transform:scale(1.15)}28%{transform:scale(1)}42%{transform:scale(1.1)}56%{transform:scale(1)}}.ej-footer p:first-of-type{color:var(--text);margin-bottom:4px;font-family:DM Serif Display,serif;font-size:1rem}.ej-footer p:last-of-type{font-size:.8rem;font-style:italic}@media (width<=700px){.ej-hero{padding:3rem 1.25rem 2.25rem}.ej-hero-back{font-size:13px;top:1rem;left:1rem}.ej-stats{gap:1.25rem}.ej-stat-num{font-size:1.6rem}.ej-main{padding:1.5rem 1rem 4rem}.ej-sec-hdr h2{font-size:1.2rem}.ej-sec-num{width:32px;height:32px;font-size:.95rem}.ej-card-top{gap:10px;padding:1rem}.ej-statement .ej-formula{font-size:1rem}.ej-sol-inner{padding:0 1rem 1rem}.ej-step p{font-size:13px}}@media (width<=380px){.ej-hero h1{font-size:1.8rem}.ej-main{padding:1.25rem .75rem 3rem}.ej-card-top{flex-direction:column;gap:6px}.ej-diff{margin-top:0}}