:root{--c-bg:#09090d;--c-surface:#101117;--c-surface-hover:#1a1b24;--c-border:rgba(244,244,245,.08);--c-border-strong:rgba(244,244,245,.14);--c-border-hover:rgba(244,244,245,.26);--c-text:#f4f4f5;--c-text-muted:#a1a1aa;--c-text-faint:#6f6f78;--c-primary:#818cf8;--c-primary-2:#c084fc;--c-on-primary:#0b0b14;--c-primary-tint:color-mix(in srgb,var(--c-primary) 13%,transparent);--c-primary-tint-strong:color-mix(in srgb,var(--c-primary) 22%,transparent);--c-primary-border:color-mix(in srgb,var(--c-primary) 34%,transparent);--c-primary-glow:color-mix(in srgb,var(--c-primary) 24%,transparent);--c-focus-ring:color-mix(in srgb,var(--c-primary) 55%,transparent);--c-sheen:linear-gradient(180deg,rgba(255,255,255,.035),transparent 46%);--font-sans:"Inter" , ui-sans-serif , system-ui , sans-serif;--font-display:"Space Grotesk" , "Inter" , ui-sans-serif , sans-serif;--font-serif:"Instrument Serif" , Georgia , serif;--font-mono:"JetBrains Mono" , ui-monospace , monospace;--space-1:.25rem;--space-2:.5rem;--space-3:.75rem;--space-4:1rem;--space-5:1.25rem;--space-6:1.5rem;--space-8:2rem;--radius-sm:.5rem;--radius-md:.75rem;--radius-lg:1rem}:root[data-mode="light"]{--c-bg:#f7f7f8;--c-surface:#fff;--c-surface-hover:#efeff2;--c-border:rgba(9,9,11,.09);--c-border-strong:rgba(9,9,11,.16);--c-border-hover:rgba(9,9,11,.3);--c-text:#18181b;--c-text-muted:#52525b;--c-text-faint:#8e8e97;--c-primary:#4f46e5;--c-primary-2:#9333ea;--c-on-primary:#fff}.ref-nav .container-xl,.rfs-nav-inner{display:flex;align-items:center;gap:var(--space-3);flex-wrap:wrap}.rfs-nav{position:sticky;top:0;z-index:1040;background:color-mix(in srgb,var(--c-bg) 82%,transparent);-webkit-backdrop-filter:blur(12px);backdrop-filter:blur(12px);border-bottom:1px solid var(--c-border);padding:.5rem 0}.rfs-brand{display:inline-flex;align-items:center;gap:var(--space-2);color:var(--c-text);font-family: var(--font-display);font-weight:600;letter-spacing:-.01em;text-decoration:none;margin-right:var(--space-2)}.rfs-brand-dot{width:8px;height:8px;border-radius:2px;background:linear-gradient(135deg,var(--c-primary),var(--c-primary-2));box-shadow:0 0 12px var(--c-primary-glow)}.rfs-links{display:flex;align-items:center;gap:var(--space-1);flex-wrap:wrap}.rfs-links a{font-size:.8rem}.rfs-actions{display:flex;align-items:center;gap:var(--space-2);margin-left:auto}.rfs-actions #theme-btn{width:2.25rem;padding:0}.rfs-hero{position:relative;overflow:hidden;padding-block:clamp(2.5rem,6vw,4.5rem);border-bottom:1px solid var(--c-border)}.rfs-hero-inner{display:grid;grid-template-columns:minmax(0,1.4fr) minmax(0,.8fr);gap:clamp(2rem,5vw,4rem);align-items:center}.rfs-eyebrow{display:flex;align-items:center;gap:var(--space-2);margin-bottom:var(--space-4);color:var(--c-text-muted);font-family: var(--font-mono);font-size:.72rem;letter-spacing:.08em;text-transform:uppercase}.rfs-eyebrow::before{content:"";width:22px;height:1px;background:var(--c-primary-border)}.rfs-hero h1{margin:0 0 var(--space-4);font-family: var(--font-display);font-size: clamp(2.25rem, 1.5rem + 4vw, 4.25rem);font-weight:600;line-height:1.02;letter-spacing:-.03em}.rfs-hero p{max-width:58ch;color:var(--c-text-muted);font-size:1.0625rem;line-height:1.7;margin-bottom:var(--space-5)}.rfs-hero-cta{display:flex;flex-wrap:wrap;gap:var(--space-3)}.rfs-bento{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:var(--space-3)}.rfs-stat{background:var(--c-surface);background-image:var(--c-sheen);border:1px solid var(--c-border);border-radius:var(--radius-lg);padding:var(--space-4);min-width:0}.rfs-stat--wide{grid-column:span 2}.rfs-stat-num{display:block;font-family: var(--font-display);font-size: clamp(2rem, 1.2rem + 2.4vw, 3rem);font-weight:600;letter-spacing:-.03em;line-height:1;margin-bottom:var(--space-2)}.rfs-stat-label{color:var(--c-text-faint);font-size:.82rem;line-height:1.45}@media (max-width:992px){.rfs-hero-inner{grid-template-columns:1fr}.rfs-bento{max-width:34rem}}@media (max-width:640px){.rfs-links{display:none}}.sec-head h2{font-family: var(--font-display);font-size: clamp(1.5rem, 1.15rem + 1.6vw, 2.1rem);font-weight:600;letter-spacing:-.02em}.sec-lead{color:var(--c-text-muted)}.gloss-card{background:var(--c-surface);background-image:var(--c-sheen);border:1px solid var(--c-border);border-radius:var(--radius-md)}.gloss-card:hover{border-color:var(--c-border-strong);box-shadow:none}.gloss-term{font-family: var(--font-display);font-weight:600}.gloss-body{background:color-mix(in srgb,var(--c-surface-2,var(--c-surface)) 90%,transparent);border-top:1px solid var(--c-border)}.cat-group-header{font-family: var(--font-mono);letter-spacing:.12em}.alpha-btn{background:var(--c-surface);border-color:var(--c-border-strong);color:var(--c-text-muted)}.alpha-btn:hover{border-color:var(--c-primary-border);color:var(--c-primary)}.q-item{background:var(--c-surface);background-image:var(--c-sheen);border:1px solid var(--c-border);border-radius:var(--radius-md)}.q-item-header{color:var(--c-text)}.q-item-body{background:color-mix(in srgb,var(--c-surface-2,var(--c-surface)) 90%,transparent);border-top:1px solid var(--c-border);color:var(--c-text-muted);font-size:.92rem;line-height:1.75}.q-option.correct{background:color-mix(in srgb,#34d399 10%,transparent);border:1px solid color-mix(in srgb,#34d399 30%,transparent)}.q-option.wrong{background:color-mix(in srgb,#f87171 7%,transparent);border:1px solid color-mix(in srgb,#f87171 20%,transparent)}.icb-item{color:var(--c-text-muted);font-size:.8rem}.icb-item:hover{background:var(--c-surface-hover);color:var(--c-text)}.sticky-search{background:var(--c-bg);border-bottom:1px solid var(--c-border)}.form-control,.form-select{background-color:var(--c-surface);border-color:var(--c-border-strong);color:var(--c-text)}.form-control:focus,.form-select:focus{background-color:var(--c-surface);border-color:var(--c-primary-border);box-shadow:0 0 0 3px var(--c-focus-ring);color:var(--c-text)}.input-group-text{background:var(--c-surface);border-color:var(--c-border-strong);color:var(--c-text-faint)}#theme-btn{display:inline-flex;align-items:center;justify-content:center}.toc-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(min(100%,13rem),1fr));gap:var(--space-3)}.toc-tile{background:var(--c-surface);background-image:var(--c-sheen);border:1px solid var(--c-border);border-radius:var(--radius-md)}.toc-tile:hover{border-color:var(--c-primary-border);box-shadow:none}.toc-ico{color:var(--c-primary);background:var(--c-primary-tint)}.model-card.card{background:var(--c-surface);background-image:var(--c-sheen);border:1px solid var(--c-border);border-radius:var(--radius-lg)}.formula-box{background:var(--c-surface-2,var(--c-surface));border-color:var(--c-border-strong);color:var(--c-text)}.doz-panel{background:color-mix(in srgb,#fbbf24 7%,var(--c-surface));border-color:var(--c-warning-border,rgba(251,191,36,.3))}.doz-action{background:var(--c-surface);border-color:var(--c-border)}.doz-action:hover{border-color:#fbbf24}.si{width:1em;height:1em;fill:none;stroke:currentColor;stroke-width:1.8;stroke-linecap:round;stroke-linejoin:round;vertical-align:-.12em;flex-shrink:0}.si--lg{width:1.35em;height:1.35em}.rfs-quick{padding-block:var(--space-8) var(--space-2)}.rfs-quick-head{display:flex;align-items:center;justify-content:space-between;margin-bottom:var(--space-4)}.rfs-quick-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(min(100%,13rem),1fr));gap:var(--space-3)}.rfs-q{display:flex;flex-direction:column;gap:var(--space-1);min-width:0;padding:var(--space-4);background:var(--c-surface);background-image:var(--c-sheen);border:1px solid var(--c-border);border-radius:var(--radius-md);color:var(--c-text);text-decoration:none;transition:border-color .15s ease , background-color .15s ease}.rfs-q:hover{border-color:var(--c-primary-border);background-color:var(--c-surface-hover)}.rfs-q-ico{display:inline-flex;align-items:center;justify-content:center;width:2rem;height:2rem;border-radius:var(--radius-sm);background:var(--c-primary-tint);color:var(--c-primary);margin-bottom:var(--space-2)}.rfs-q-tt{font-family: var(--font-display);font-weight:600;font-size:.95rem;letter-spacing:-.01em;color:var(--c-text)}.rfs-q-sub{color:var(--c-text-faint);font-size:.78rem;line-height:1.4}#theme-ic{pointer-events:none}.container{width:100%;max-width:76rem;margin-inline:auto;padding-inline:clamp(1rem,4vw,2rem)}.serif-i{font-family: var(--font-serif);font-style:italic;font-weight:400;letter-spacing:-.01em}.tag{display:inline-flex;align-items:center;gap:.375rem;padding:.125rem .5rem;border:1px solid var(--c-border-strong);border-radius:999px;background:transparent;color:var(--c-text-muted);font-family: var(--font-mono);font-size:.6875rem;font-weight:500;line-height:1.6;letter-spacing:.08em;text-transform:uppercase;white-space:nowrap}.tag--accent{color:var(--c-primary);border-color:var(--c-primary-border);background:var(--c-primary-tint)}.btn{display:inline-flex;align-items:center;justify-content:center;gap:.375rem;min-height:2.25rem;padding:.375rem .9375rem;border:1px solid transparent;border-radius:.5rem;background:transparent;color:var(--c-text);font-family: var(--font-sans);font-size:.875rem;font-weight:600;line-height:1.2;text-decoration:none;white-space:nowrap;cursor:pointer;-webkit-tap-highlight-color:transparent;transition:background-color .15s ease , border-color .15s ease , color .15s ease}.btn--sm{min-height:1.875rem;padding:.1875rem .625rem;font-size:.8125rem}.btn .si{width:1.1em;height:1.1em}.btn--primary{background:linear-gradient(135deg,var(--c-primary) 0%,var(--c-primary-2) 110%);color:var(--c-on-primary);box-shadow:inset 0 1px 0 rgba(255,255,255,.14) , 0 8px 24px -14px var(--c-primary-glow)}.btn--primary:hover{filter:saturate(1.04) brightness(1.05)}.btn--outline{background:var(--c-surface);border-color:var(--c-border-strong);color:var(--c-text)}.btn--outline:hover{background:var(--c-surface-hover);border-color:var(--c-border-hover)}.btn--ghost{color:var(--c-text-muted)}.btn--ghost:hover{background:var(--c-surface-hover);color:var(--c-text)}.rfs-hero-inner{grid-template-columns:minmax(0,1.25fr) minmax(0,.95fr)}.rfs-stats{display:flex;flex-wrap:wrap;gap:.5rem;margin-top:var(--space-5)}.rfs-chip{display:inline-flex;align-items:baseline;gap:.5rem;padding:.375rem .75rem;background:var(--c-surface);border:1px solid var(--c-border);border-radius:var(--radius-md)}.rfs-chip b{font-family: var(--font-display);font-size:1.05rem;font-weight:600;letter-spacing:-.01em;color:var(--c-text)}.rfs-chip span{color:var(--c-text-faint);font-size:.72rem}.rfs-qpanel{background:var(--c-surface);background-image:var(--c-sheen);border:1px solid var(--c-border);border-radius:var(--radius-lg);padding:var(--space-3)}.rfs-qpanel-head{display:flex;align-items:center;justify-content:space-between;gap:var(--space-2);padding:.375rem .5rem .625rem}.rfs-qrow{display:flex;align-items:center;gap:var(--space-3);width:100%;padding:.5rem .625rem;border-radius:var(--radius-sm);color:var(--c-text);text-decoration:none;transition:background-color .15s ease}.rfs-qrow:hover{background:var(--c-surface-hover)}.rfs-qrow+.rfs-qrow{margin-top:.125rem}.rfs-qrow-ico{display:inline-flex;align-items:center;justify-content:center;width:1.9rem;height:1.9rem;flex-shrink:0;border-radius:var(--radius-sm);background:var(--c-primary-tint);color:var(--c-primary)}.rfs-qrow-main{flex:1 1 auto;min-width:0;display:flex;flex-direction:column;line-height:1.35}.rfs-qrow-tt{font-family: var(--font-display);font-size:.9rem;font-weight:600;letter-spacing:-.01em;color:var(--c-text)}.rfs-qrow-sub{color:var(--c-text-faint);font-size:.74rem}.rfs-qrow-arrow{color:var(--c-text-faint);opacity:0;transition:opacity .15s ease , transform .15s ease , color .15s ease}.rfs-qrow:hover .rfs-qrow-arrow{opacity:1;transform:translateX(2px);color:var(--c-primary)}.rfs-qrow--cta{margin-top:var(--space-2);background:var(--c-primary-tint);border:1px solid var(--c-primary-border);border-radius:var(--radius-md);padding:.625rem}.rfs-qrow--cta:hover{background:var(--c-primary-tint-strong)}.rfs-qrow--cta .rfs-qrow-tt{color:var(--c-primary)}.si--arrow{width:1.1em;height:1.1em}