:root{--bg-base:#f7f5f0;--bg-surface:#fff;--bg-elevated:#fffef9;--bg-warm:#f0ede5;--bg-hero:#1c1917;--accent:#9a3412;--accent-hover:#7c2d12;--accent-light:#fdba74;--accent-pale:#fff7ed;--accent-glow:#9a341214;--blue:#1e3a5f;--blue-light:#3b6fa0;--blue-pale:#eff6ff;--solved:#15803d;--solved-bg:#f0fdf4;--solved-border:#bbf7d0;--text-primary:#1c1917;--text-secondary:#57534e;--text-muted:#a8a29e;--text-inverse:#fafaf9;--border:#e7e5e4;--border-strong:#d6d3cd;--border-accent:#9a341233;--font-display:"Fraunces","Georgia",serif;--font-body:"Newsreader","Georgia",serif;--font-mono:"JetBrains 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a{font-family:var(--font-body);color:var(--text-secondary);font-size:.95rem;font-weight:500;text-decoration:none;transition:color .2s}.header-nav a:hover{color:var(--accent)}.nav-external{align-items:center;gap:.35rem;display:flex}.nav-external svg{opacity:.5;width:13px;height:13px;transition:opacity .2s}.nav-external:hover svg{opacity:.8}.hero{background:var(--bg-hero);color:var(--text-inverse);padding:6rem 2rem 5.5rem;position:relative;overflow:hidden}.hero:before{content:"";pointer-events:none;background:radial-gradient(70% 70% at 20%,#9a34121f 0%,#0000 70%),radial-gradient(50% 60% at 80% 30%,#1e3a5f1a 0%,#0000 70%);position:absolute;inset:0}.hero:after{content:"";pointer-events:none;background-image:linear-gradient(#ffffff08 1px,#0000 1px),linear-gradient(90deg,#ffffff08 1px,#0000 1px);background-size:60px 60px;position:absolute;inset:0}.hero-inner{max-width:var(--content-max);z-index:1;margin:0 auto;position:relative}.hero-label{font-family:var(--font-mono);letter-spacing:.12em;text-transform:uppercase;color:var(--accent-light);opacity:0;animation:fadeUp .8s var(--ease-out-expo).1s forwards;align-items:center;gap:.5rem;margin-bottom:1.5rem;font-size:.75rem;font-weight:500;display:inline-flex}.hero-label:before{content:"";background:var(--accent-light);opacity:.5;width:32px;height:1px}.hero h1{letter-spacing:-.03em;opacity:0;max-width:700px;animation:fadeUp .8s var(--ease-out-expo).2s forwards;margin-bottom:1.5rem;font-size:clamp(2.5rem,5vw,3.8rem);font-weight:900;line-height:1.08}.hero-subtitle{font-family:var(--font-body);color:#fafaf9a6;opacity:0;max-width:560px;animation:fadeUp .8s var(--ease-out-expo).35s forwards;font-size:1.2rem;line-height:1.7}.hero-stats{opacity:0;animation:fadeUp .8s var(--ease-out-expo).5s forwards;border-top:1px solid #ffffff14;gap:3rem;margin-top:3rem;padding-top:2rem;display:flex}.stat{flex-direction:column;display:flex}.stat-number{font-family:var(--font-display);color:var(--accent-light);letter-spacing:-.02em;font-size:2.2rem;font-weight:800;line-height:1}.stat-label{font-family:var(--font-mono);letter-spacing:.1em;text-transform:uppercase;color:#fafaf966;margin-top:.4rem;font-size:.7rem}.solutions{max-width:var(--content-max);padding:var(--section-gap)2rem;margin:0 auto}.solutions-header{margin-bottom:3.5rem}.solutions-header h2{margin-bottom:.5rem;font-size:1.8rem;font-weight:700}.solutions-header p{color:var(--text-secondary);max-width:600px;font-size:1.05rem}.solutions-grid{flex-direction:column;gap:2.5rem;display:flex}.solution-card{background:var(--bg-surface);border:1px solid var(--border);opacity:0;animation:fadeUp .7s var(--ease-out-expo)forwards;border-radius:12px;transition:border-color .3s,box-shadow 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var(--border-accent)}.card-problem{font-family:var(--font-mono);color:var(--text-muted);letter-spacing:.04em;margin-bottom:.5rem;font-size:.75rem}.card-title{font-family:var(--font-display);letter-spacing:-.015em;color:var(--text-primary);margin-bottom:1rem;font-size:1.5rem;font-weight:700;line-height:1.25}.card-description{color:var(--text-secondary);margin-bottom:1.5rem;font-size:1rem;line-height:1.72}.card-math{background:var(--bg-base);border:1px solid var(--border);text-align:center;border-radius:8px;margin:1.5rem 0;padding:1.5rem 2rem;overflow-x:auto}.card-math .math-label{font-family:var(--font-mono);letter-spacing:.1em;text-transform:uppercase;color:var(--text-muted);margin-bottom:.75rem;font-size:.65rem;font-weight:500}.card-math .katex{font-size:1.15rem}.card-math .katex-display{margin:0}.card-actions{border-top:1px solid var(--border);background:var(--bg-elevated);align-items:center;gap:1rem;padding:1.25rem 2.5rem;display:flex}.btn{font-family:var(--font-body);cursor:pointer;border:none;border-radius:6px;align-items:center;gap:.5rem;padding:.6rem 1.2rem;font-size:.9rem;font-weight:600;text-decoration:none;transition:all .2s;display:inline-flex}.btn-primary{background:var(--accent);color:#fff}.btn-primary:hover{background:var(--accent-hover);color:#fff;transform:translateY(-1px);box-shadow:0 4px 12px #9a341240}.btn-secondary{color:var(--text-secondary);border:1px solid var(--border);background:0 0}.btn-secondary:hover{background:var(--bg-base);color:var(--text-primary);border-color:var(--border-strong)}.btn svg{width:16px;height:16px}.footer{border-top:1px solid var(--border);margin-top:2rem;padding:3rem 2rem}.footer-inner{max-width:var(--content-max);justify-content:space-between;align-items:center;margin:0 auto;display:flex}.footer-text{color:var(--text-muted);font-size:.9rem}.footer-text a{color:var(--text-secondary);text-underline-offset:3px;text-decoration:underline;-webkit-text-decoration-color:var(--border);text-decoration-color:var(--border)}.footer-text a:hover{color:var(--accent);-webkit-text-decoration-color:var(--accent);text-decoration-color:var(--accent)}.footer-links{gap:1.5rem;display:flex}.footer-links a{color:var(--text-muted);font-size:.85rem}.footer-links a:hover{color:var(--accent)}@keyframes fadeUp{0%{opacity:0;transform:translateY(20px)}to{opacity:1;transform:translateY(0)}}@media (max-width:768px){.hero{padding:4rem 1.5rem 3.5rem}.hero-stats{gap:2rem}.stat-number{font-size:1.6rem}.card-content{padding:1.75rem 1.5rem 1.25rem}.card-actions{flex-wrap:wrap;padding:1rem 1.5rem}.card-math{padding:1rem 1.25rem}.header-inner{padding:.85rem 1.5rem}.solutions{padding:var(--section-gap)1.5rem}.footer-inner{text-align:center;flex-direction:column;gap:1rem}}@media (max-width:480px){.hero h1{font-size:2rem}.hero-stats{flex-wrap:wrap;gap:1.5rem}.card-title{font-size:1.25rem}.header-nav{gap:1rem}}