:root{--paper:#f9f9f9;--card:#f5f5f5;--border:#e8e8e8;--text:#2d2d2d;--secondary:#5a5a5a;--muted:#999;--accent:#06c;--selection-bg:#00000014;--font-serif:Charter, Georgia, serif;--font-sans:"SF Pro", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;--font-mono:ui-monospace, "SFMono-Regular", "SF Mono", Menlo, Consolas, monospace;--space-1:.25rem;--space-2:.5rem;--space-3:.75rem;--space-4:1rem;--space-5:1.25rem;--space-6:1.5rem;--space-8:2rem;--space-10:2.5rem;--space-12:3rem;--space-16:4rem}[data-theme=dark]{--paper:#000;--card:#1c1c1e;--border:#2c2c2e;--text:#d1d1d1;--secondary:#888;--muted:#666;--accent:#5c9dff;--selection-bg:#ffffff1f}html{height:100%}body{min-height:100%;color:var(--text);background:var(--paper);font-family:var(--font-serif);letter-spacing:.01em;-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale;text-rendering:optimizelegibility;flex-direction:column;font-size:1.0625rem;line-height:1.7;display:flex}*{box-sizing:border-box;margin:0;padding:0}::selection{background:var(--selection-bg);color:var(--text)}*,:before,:after{transition-duration:0s!important;animation-duration:0s!important}.app-header{z-index:50;background:var(--paper);border-bottom:1px solid var(--border);position:sticky;top:0}.app-nav{justify-content:space-between;align-items:center;max-width:800px;height:52px;margin:0 auto;padding:0 1.5rem;display:flex}.nav-brand{color:var(--text);font-family:var(--font-sans);letter-spacing:.02em;font-size:.9375rem;font-weight:500;text-decoration:none}.nav-links{align-items:center;gap:1.5rem;display:flex}.nav-actions{align-items:center;gap:.75rem;display:flex}.auth-btn{color:var(--secondary);cursor:pointer;font-family:var(--font-sans);text-transform:uppercase;letter-spacing:.06em;background:0 0;border:none;padding:0;font-size:.8125rem;font-weight:500}.auth-btn:hover{color:var(--text)}.nav-link{color:var(--secondary);font-family:var(--font-sans);text-transform:uppercase;letter-spacing:.06em;font-size:.8125rem;font-weight:500;text-decoration:none}.nav-link:hover{color:var(--text)}.app-main{flex:1;width:100%;max-width:800px;margin:0 auto;padding:3rem 1.5rem}h1,h2,h3,h4,h5,h6{font-family:var(--font-serif);color:var(--text);font-weight:400;line-height:1.3}:focus-visible{outline:2px solid var(--accent);outline-offset:2px}a{color:var(--accent);text-decoration:none}a:hover{text-decoration:underline}.katex{color:var(--text);font-size:1.05em}.katex-display{margin:1.5rem 0;overflow-x:auto}.theme-toggle{color:var(--secondary);cursor:pointer;background:0 0;border:none;justify-content:center;align-items:center;padding:.25rem;display:flex}.theme-toggle:hover{color:var(--text)}@media (prefers-reduced-motion:reduce){*,:before,:after{transition-duration:0s!important;animation-duration:0s!important}}