:root{color-scheme:light;font-family:-apple-system,BlinkMacSystemFont,SF Pro Text,SF Pro Display,PingFang SC,Hiragino Sans GB,Microsoft YaHei,sans-serif;font-synthesis:none;text-rendering:optimizeLegibility;-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale;--ink: #1d1d1f;--ink-secondary: #515154;--muted: #6e6e73;--quiet: #86868b;--line: rgba(0, 0, 0, .07);--line-subtle: rgba(0, 0, 0, .04);--blue: #0071e3;--blue-hover: #0077ed;--blue-soft: rgba(0, 113, 227, .08);--blue-border: rgba(0, 113, 227, .16);--paper: #ffffff;--canvas: #f5f5f7;--canvas-alt: #fbfbfd;--gain: #e02424;--gain-soft: rgba(224, 36, 36, .08);--gain-border: rgba(224, 36, 36, .18);--loss: #059669;--loss-soft: rgba(5, 150, 105, .08);--loss-border: rgba(5, 150, 105, .18);--radius-xs: 6px;--radius-sm: 10px;--radius-md: 14px;--radius-lg: 20px;--radius-pill: 9999px;--shadow-subtle: 0 1px 3px rgba(0, 0, 0, .04), 0 1px 2px rgba(0, 0, 0, .02);--shadow-card: 0 2px 8px -1px rgba(0, 0, 0, .04), 0 1px 3px -1px rgba(0, 0, 0, .02);--shadow-elevated: 0 12px 32px -4px rgba(0, 0, 0, .08), 0 4px 12px -2px rgba(0, 0, 0, .03);--shadow-hero: 0 16px 36px -6px rgba(0, 0, 0, .08), 0 4px 12px -2px rgba(0, 0, 0, .03)}*{box-sizing:border-box;margin:0;padding:0}html{min-width:320px;min-height:100%;scroll-behavior:smooth;background-color:var(--canvas)}body{min-width:320px;min-height:100vh;margin:0;background:var(--canvas);color:var(--ink);line-height:1.6}a{color:inherit;text-decoration:none;-webkit-tap-highlight-color:transparent}a:focus-visible,button:focus-visible{outline:2px solid var(--blue);outline-offset:2px;border-radius:var(--radius-xs)}.site-header{position:sticky;top:0;z-index:50;border-bottom:1px solid var(--line);background:#ffffffd9;backdrop-filter:blur(20px) saturate(180%);-webkit-backdrop-filter:blur(20px) saturate(180%)}.site-header-inner,.page-shell,.site-footer-inner{width:min(1060px,calc(100% - 40px));margin-inline:auto}.site-header-inner{display:flex;min-height:64px;align-items:center;justify-content:space-between;gap:20px}.site-brand{display:inline-flex;align-items:center;gap:12px}.brand-mark{display:grid;width:36px;height:36px;place-items:center;border-radius:var(--radius-sm);background:linear-gradient(135deg,#1d4ed8,#0284c7);box-shadow:0 4px 12px #0284c740}.brand-mark svg{width:20px;height:20px;fill:none;stroke:#fff;stroke-linecap:round;stroke-linejoin:round;stroke-width:2.2}.site-brand span:last-child{display:grid;gap:1px}.site-brand strong{font-size:15px;font-weight:700;letter-spacing:-.01em;color:var(--ink)}.site-brand small{color:var(--muted);font-size:11px}.site-nav{display:flex;align-items:center;gap:20px;font-size:13px;font-weight:600}.site-nav a{color:var(--ink-secondary);transition:color .15s ease}.site-nav a[aria-current=page],.site-nav a:hover{color:var(--blue)}.site-nav .login-link{padding:7px 16px;border-radius:var(--radius-pill);background:var(--blue);color:#fff!important;font-size:13px;font-weight:600;box-shadow:0 2px 8px #06c3;transition:background-color .15s ease,transform .15s ease}.site-nav .login-link:hover{background:var(--blue-hover);transform:translateY(-1px)}.page-shell{padding-block:28px 80px}.breadcrumbs{display:flex;align-items:center;gap:8px;color:var(--muted);font-size:12px;font-weight:500}.breadcrumbs a{color:var(--muted);transition:color .15s ease}.breadcrumbs a:hover{color:var(--blue)}.breadcrumbs span[aria-hidden=true]{color:var(--quiet);font-size:11px}.eyebrow{display:inline-flex;align-items:center;gap:6px;color:var(--blue);font-size:12px;font-weight:700;letter-spacing:.04em;text-transform:uppercase}.hero{display:grid;grid-template-columns:minmax(0,1.2fr) minmax(280px,.8fr);align-items:center;gap:clamp(32px,6vw,64px);padding-block:clamp(36px,6vw,64px) 36px}.hero h1{max-width:680px;margin-top:10px;font-size:clamp(32px,5vw,48px);font-weight:800;line-height:1.2;letter-spacing:-.02em;color:var(--ink)}.hero-copy{margin-top:12px;color:var(--ink-secondary);font-size:15px;line-height:1.75}.hero-copy strong{color:var(--ink);font-weight:700}.updated{display:block;margin-top:14px;color:var(--quiet);font-size:12px}.answer-card{display:grid;grid-template-columns:minmax(0,.8fr) minmax(0,1.2fr);gap:clamp(24px,4vw,48px);padding:clamp(24px,4vw,36px);border:1px solid var(--line);border-radius:var(--radius-lg);background:var(--paper);box-shadow:var(--shadow-card)}.answer-card h2,.content-section h2,.faq-section h2,.about-principles h2{margin-top:8px;font-size:clamp(22px,3.2vw,32px);font-weight:800;line-height:1.25;letter-spacing:-.02em;color:var(--ink)}.answer-card p:last-child{margin:0;color:var(--ink-secondary);font-size:15px;line-height:1.8}.topic-nav{display:flex;flex-wrap:wrap;gap:8px;margin-top:18px}.topic-nav a{padding:6px 14px;border:1px solid var(--line);border-radius:var(--radius-pill);background:var(--paper);color:var(--ink-secondary);font-size:12px;font-weight:600;box-shadow:var(--shadow-subtle);transition:background-color .15s ease,color .15s ease,border-color .15s ease}.topic-nav a:hover{background:var(--blue-soft);border-color:var(--blue-border);color:var(--blue)}.content-section{display:grid;grid-template-columns:minmax(220px,.55fr) minmax(0,1.45fr);gap:clamp(32px,6vw,64px);padding-block:48px;border-bottom:1px solid var(--line);scroll-margin-top:80px}.content-section:last-of-type{border-bottom:0}.section-body{min-width:0}.section-body>p{color:var(--ink-secondary);font-size:15px;line-height:1.8}.section-body>p+p{margin-top:14px}.fact-grid,.principle-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:14px;margin-top:24px}.fact-card,.principle-card{min-width:0;padding:20px;border:1px solid var(--line);border-radius:var(--radius-md);background:var(--paper);box-shadow:var(--shadow-subtle);transition:transform .16s ease,box-shadow .16s ease}.fact-card:hover,.principle-card:hover{transform:translateY(-2px);box-shadow:var(--shadow-card)}.fact-card h3,.principle-card h3{font-size:15px;font-weight:700;color:var(--ink)}.fact-card p,.principle-card p{margin-top:8px;color:var(--muted);font-size:13px;line-height:1.65}.formula-list{display:grid;gap:12px;margin-top:24px}.formula-item{display:grid;grid-template-columns:130px minmax(0,1fr);gap:16px;padding:16px 20px;border-radius:var(--radius-md);background:var(--paper);border:1px solid var(--line);box-shadow:var(--shadow-subtle)}.formula-item strong{font-size:14px;font-weight:700;color:var(--ink)}.formula-item span{color:var(--ink-secondary);font-size:13px;line-height:1.6}.note-card{margin-top:24px;padding:16px 20px;border-left:3px solid var(--blue);border-radius:var(--radius-sm);background:var(--blue-soft);color:var(--ink-secondary);font-size:13px;line-height:1.7}.faq-section,.about-principles{padding:48px 0 24px}.faq-list{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:14px;margin-top:28px}.faq-list article{padding:22px;border:1px solid var(--line);border-radius:var(--radius-md);background:var(--paper);box-shadow:var(--shadow-subtle)}.faq-list h3{font-size:15px;font-weight:700;color:var(--ink)}.faq-list p{margin-top:8px;color:var(--muted);font-size:13px;line-height:1.65}.about-hero{grid-template-columns:minmax(0,1.1fr) minmax(280px,.9fr)}.identity-card{padding:28px;border:1px solid var(--line);border-radius:var(--radius-lg);background:var(--paper);box-shadow:var(--shadow-hero)}.identity-card span{color:var(--blue);font-size:12px;font-weight:700}.identity-card strong{display:block;margin-top:6px;font-size:22px;font-weight:800;color:var(--ink)}.identity-card p{margin-top:10px;color:var(--muted);font-size:13px;line-height:1.7}.identity-links{display:flex;flex-wrap:wrap;gap:8px;margin-top:18px}.identity-links a{padding:6px 14px;border-radius:var(--radius-pill);background:var(--blue-soft);color:var(--blue);font-size:12px;font-weight:600;transition:background-color .15s ease}.identity-links a:hover{background:#dbeafe}.cta-panel{display:flex;align-items:center;justify-content:space-between;gap:24px;margin-top:48px;padding:32px 36px;border-radius:var(--radius-lg);background:#1d1d1f;border:1px solid rgba(255,255,255,.08);color:#fff;box-shadow:var(--shadow-elevated)}.cta-panel strong{font-size:20px;font-weight:700;color:#fff}.cta-panel span{display:block;margin-top:4px;color:#a1a1a6;font-size:13px}.cta-panel a{flex:0 0 auto;padding:12px 24px;border-radius:var(--radius-pill);background:var(--blue);color:#fff;font-size:14px;font-weight:600;box-shadow:0 2px 8px #0071e34d;transition:transform .15s ease,background-color .15s ease}.cta-panel a:hover{transform:translateY(-1px);background:var(--blue-hover)}.site-footer{border-top:1px solid var(--line);background:var(--paper)}.site-footer-inner{display:flex;min-height:72px;align-items:center;justify-content:space-between;gap:20px;color:var(--muted);font-size:12px}.footer-links{display:flex;gap:16px}.footer-links a{color:var(--muted);transition:color .15s ease}.footer-links a:hover{color:var(--blue)}@media(max-width:760px){.site-header-inner,.page-shell,.site-footer-inner{width:min(100% - 24px,1060px)}.site-nav a:not(.login-link){display:none}.hero,.answer-card,.content-section,.fact-grid,.principle-grid,.faq-list{grid-template-columns:1fr}.hero{gap:24px;padding-block:36px 32px}.formula-item{grid-template-columns:1fr;gap:6px}.cta-panel,.site-footer-inner{align-items:flex-start;flex-direction:column}.cta-panel a{text-align:center;width:100%}.site-footer-inner{padding-block:20px}}@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*,*:before,*:after{transition:none!important;animation:none!important}}