:root{--bg:#f8f9fa;--bg-pattern:#fff;--surface:#fff;--text:#1a1a1a;--text-muted:#4a5568;--accent:#2563eb;--accent-dark:#1e40af;--accent-soft:rgba(37,99,235,.1);--border:#e2e8f0;--math-accent:#1e40af;--font-heading:"Crimson Text","Times New Roman",serif;--font-body:"Inter",system-ui,sans-serif;--font-math:"Crimson Text","Times New Roman",serif;--font-code:"Source Code Pro",monospace}*{box-sizing:border-box;padding:0;margin:0}html{scroll-behavior:smooth}body{font-family:var(--font-body);background:var(--bg);background-image:linear-gradient(rgba(37,99,235,.02) 1px,transparent 0),linear-gradient(90deg,rgba(37,99,235,.02) 1px,transparent 0);background-size:40px 40px;color:var(--text);line-height:1.7;min-height:100vh;position:relative}body:before{content:"";position:fixed;top:0;left:0;right:0;bottom:0;background:radial-gradient(circle at 10% 20%,rgba(37,99,235,.03) 0,transparent 50%),radial-gradient(circle at 90% 80%,rgba(30,64,175,.03) 0,transparent 50%);pointer-events:none;z-index:0}a{color:var(--accent);text-decoration:none;transition:color .2s}a:hover{text-decoration:underline;-webkit-text-decoration-color:var(--accent);text-decoration-color:var(--accent)}a:hover,h1,h2,h3{color:var(--math-accent)}h1,h2,h3{font-family:var(--font-heading);font-weight:600;letter-spacing:-.01em}h1{font-size:2rem;position:relative;padding-bottom:.5rem}h1:after{content:"";position:absolute;bottom:0;left:0;width:80px;height:3px;background:linear-gradient(90deg,var(--accent),rgba(37,99,235,.3));border-radius:2px}.container{max-width:720px;margin:0 auto;padding:0 1.5rem;position:relative;z-index:1}.nav{position:-webkit-sticky;position:sticky;top:0;z-index:10;background:hsla(0,0%,100%,.95);-webkit-backdrop-filter:blur(12px);backdrop-filter:blur(12px);border-bottom:2px solid var(--border);box-shadow:0 1px 3px rgba(0,0,0,.05)}.nav-inner{max-width:720px;margin:0 auto;padding:0 1.5rem;display:flex;align-items:center;justify-content:space-between;min-height:3.5rem}.logo{font-family:var(--font-heading);font-weight:600;font-size:1.15rem;color:var(--math-accent);letter-spacing:.02em}.tabs{display:flex;gap:.25rem;flex-wrap:wrap}.tab{display:inline-block;padding:.5rem .9rem;font-size:.9rem;font-weight:500;font-family:var(--font-body);color:var(--text-muted);border-radius:6px;transition:all .2s;position:relative}.tab.active,.tab:hover{color:var(--math-accent);background:var(--accent-soft)}.tab.active{font-weight:600}.tab.active:after{content:"";position:absolute;bottom:-2px;left:.9rem;right:.9rem;height:2px;background:var(--accent);border-radius:1px}.main{padding:0;position:relative;z-index:1}.page-section{padding:3rem 0 4rem;min-height:60vh;scroll-margin-top:80px}.page-section:first-child{padding-top:2.5rem}.page-title{font-size:2rem;color:var(--math-accent)}.page-title,.section{margin-bottom:2rem}.section h2{font-size:1.15rem;margin-bottom:.5rem;color:var(--text)}.section p,.section ul{color:var(--text-muted);font-size:.95rem}.section ul{padding-left:1.25rem;margin-top:.5rem}.card{background:var(--surface);border:1px solid var(--border);border-left:4px solid var(--accent);border-radius:8px;padding:1.5rem;margin-bottom:1.5rem;box-shadow:0 2px 8px rgba(0,0,0,.04);transition:all .3s ease}.card:hover{box-shadow:0 4px 16px rgba(37,99,235,.1);transform:translateY(-2px);border-left-color:var(--math-accent)}.card h3{font-size:1.1rem;margin-bottom:.5rem;color:var(--math-accent);font-family:var(--font-heading);font-weight:600}.card p{font-size:.9rem;color:var(--text-muted)}.card a{font-size:.9rem;color:var(--accent);font-weight:500}.card a:hover{color:var(--math-accent)}.math-formula{font-style:italic;background:var(--accent-soft);padding:.15em .4em;border-radius:4px;display:inline-block;margin:0 .2em;font-size:1.05em}.math-formula,.math-symbol{font-family:var(--font-math);color:var(--math-accent)}.math-symbol{font-weight:600;margin:0 .15em}