:root{--bg:#f7f8fc;--surface:#fff;--surface2:#f1f3f9;--text:#16192b;--muted:#626a7d;--line:#e3e6ef;--primary:#5b63f6;--primary2:#4249d8;--soft:#eef0ff;--good:#16845a;--danger:#c23e3e;--shadow:0 18px 50px rgba(31,38,68,.08);--max:1180px;--radius:22px}
:root[data-theme="dark"]{--bg:#0e1120;--surface:#15192b;--surface2:#1c2137;--text:#f5f6fb;--muted:#a7aec2;--line:#2b314b;--soft:#20274b;--shadow:0 20px 60px rgba(0,0,0,.26)}
*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;background:var(--bg);color:var(--text);font-family:Inter,ui-sans-serif,system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;line-height:1.6;-webkit-font-smoothing:antialiased}a{color:inherit;text-decoration:none}button,input,select,textarea{font:inherit}.wrap{width:min(var(--max),calc(100% - 40px));margin:auto}.narrow{max-width:820px}.site-header{height:72px;display:flex;align-items:center;position:sticky;top:0;z-index:80;background:color-mix(in srgb,var(--bg) 88%,transparent);backdrop-filter:blur(18px);border-bottom:1px solid color-mix(in srgb,var(--line) 65%,transparent)}.header-inner{display:flex;align-items:center;gap:26px}.brand{display:flex;align-items:center;gap:9px;font-size:21px;font-weight:900;letter-spacing:-.035em;white-space:nowrap}.brand-mark{width:34px;height:34px;border-radius:11px;display:grid;place-items:center;background:linear-gradient(135deg,var(--primary),#8a67ff);color:#fff;font-weight:900;box-shadow:0 7px 18px rgba(91,99,246,.23)}.main-nav{display:flex;gap:5px;margin-left:auto}.main-nav a{padding:9px 12px;border-radius:11px;color:var(--muted);font-size:14px;font-weight:750}.main-nav a:hover{background:var(--surface2);color:var(--text)}.icon-btn{width:40px;height:40px;border:1px solid var(--line);border-radius:12px;background:var(--surface);color:var(--text);display:grid;place-items:center;cursor:pointer}.icon-btn:hover{background:var(--surface2)}
.eyebrow{font-size:11px;text-transform:uppercase;letter-spacing:.12em;font-weight:850;color:var(--primary)}h1,h2,h3,p{margin-top:0}h1,h2,h3{letter-spacing:-.035em;line-height:1.12}h1{font-size:clamp(42px,6vw,74px);margin-bottom:20px}h2{font-size:clamp(27px,3vw,38px);margin-bottom:12px}h3{font-size:19px}.hero{padding:82px 0 72px;background:radial-gradient(circle at 80% 15%,rgba(91,99,246,.14),transparent 34%),linear-gradient(180deg,var(--surface),var(--bg));border-bottom:1px solid var(--line)}.hero-grid{display:grid;grid-template-columns:minmax(0,1.25fr) minmax(300px,.75fr);gap:72px;align-items:center}.hero h1 span{color:var(--primary)}.hero-copy{font-size:19px;color:var(--muted);max-width:720px}.hero-eyebrow{display:inline-flex;margin-bottom:18px}.search-box{height:62px;border:1px solid var(--line);background:var(--surface);border-radius:18px;display:flex;align-items:center;gap:12px;padding:0 16px;box-shadow:var(--shadow);position:relative}.search-box>span{font-size:27px;color:var(--muted)}.search-box input{border:0;outline:0;background:transparent;color:var(--text);width:100%;font-size:17px}.search-box kbd{border:1px solid var(--line);background:var(--surface2);border-radius:8px;padding:3px 7px;color:var(--muted);font-size:11px}.home-search{margin-top:30px;max-width:720px}.home-search-results{position:absolute;z-index:55;margin-top:9px;width:min(720px,calc(100% - 40px));background:var(--surface);border:1px solid var(--line);border-radius:18px;box-shadow:0 24px 70px rgba(23,27,48,.18);padding:8px}.home-search-results[hidden]{display:none}.home-search-result,.global-search-result{display:grid;grid-template-columns:auto 1fr auto;gap:12px;align-items:center;padding:11px;border-radius:13px}.home-search-result:hover,.global-search-result:hover{background:var(--surface2)}.home-search-result>span:nth-child(2),.global-search-result>span:nth-child(2){display:flex;flex-direction:column}.home-search-result small,.global-search-result small{color:var(--muted);font-size:13px}.search-result-badge{width:38px;height:38px;border-radius:11px;display:grid;place-items:center;background:var(--soft);color:var(--primary);font-size:11px;font-weight:850}.search-empty{padding:18px;display:flex;flex-direction:column}.search-empty span{color:var(--muted);font-size:13px}.quick-links{display:flex;align-items:center;gap:8px;flex-wrap:wrap;margin-top:16px}.quick-links span{font-size:13px;color:var(--muted);font-weight:750}.quick-links a{font-size:13px;font-weight:800;padding:7px 10px;background:var(--surface2);border-radius:999px}.hero-panel{background:linear-gradient(145deg,#171b33,#252b51);color:#fff;border-radius:30px;padding:28px;box-shadow:0 32px 80px rgba(28,34,74,.22);transform:rotate(1.2deg)}.hero-panel-top{display:grid;grid-template-columns:1fr auto;align-items:end;padding-bottom:24px;border-bottom:1px solid rgba(255,255,255,.12)}.hero-panel-top span{grid-column:1/-1;color:#b8c0e0;font-size:12px;text-transform:uppercase;letter-spacing:.1em;font-weight:800}.hero-panel-top strong{font-size:70px;line-height:1;font-weight:900;letter-spacing:-.08em}.hero-panel-top small{font-size:13px;color:#bdc4df;padding-bottom:9px}.hero-panel-grid{display:grid;grid-template-columns:1fr 1fr;gap:14px;padding-top:20px}.hero-panel-grid div{background:rgba(255,255,255,.06);border-radius:16px;padding:14px}.hero-panel-grid b{display:block;font-size:20px}.hero-panel-grid span{color:#bfc6df;font-size:11px}
.section{padding:72px 0}.section-head{display:flex;align-items:end;justify-content:space-between;gap:24px;margin-bottom:28px}.section-head p{color:var(--muted);margin:5px 0 0}.section-head.compact{align-items:center}.formula-strip{padding:46px 0;background:var(--surface);border-bottom:1px solid var(--line)}.formula-grid{display:grid;grid-template-columns:repeat(6,1fr);gap:10px}.formula-card{display:flex;flex-direction:column;gap:5px;padding:15px;border:1px solid var(--line);border-radius:16px;background:var(--bg);min-width:0}.formula-card:hover{border-color:color-mix(in srgb,var(--primary) 45%,var(--line));transform:translateY(-2px)}.formula-card code{font-size:16px;color:var(--primary);font-weight:850;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}.formula-card span{font-size:14px;font-weight:800}.formula-card b{display:none}.category-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:16px}.category-card{border:1px solid var(--line);background:var(--surface);border-radius:22px;padding:22px;display:grid;grid-template-columns:auto 1fr auto;gap:16px;box-shadow:0 8px 28px rgba(24,30,55,.035);transition:.2s}.category-card:hover{transform:translateY(-3px);box-shadow:var(--shadow);border-color:color-mix(in srgb,var(--primary) 28%,var(--line))}.category-card-icon,.calc-symbol{width:52px;height:52px;border-radius:16px;display:grid;place-items:center;font-weight:900;font-size:17px;background:var(--soft);color:var(--primary)}.category-card-icon.green,.calc-symbol.green{background:#e7f7ef;color:#167453}.category-card-icon.blue,.calc-symbol.blue{background:#e9f1ff;color:#3b67c7}.category-card-icon.cyan,.calc-symbol.cyan{background:#e7f8fb;color:#16768a}.category-card-icon.amber,.calc-symbol.amber{background:#fff3d9;color:#a66b00}.category-card-icon.rose,.calc-symbol.rose{background:#ffedf2;color:#a94462}.category-card-icon.violet,.calc-symbol.violet{background:#efebff;color:#6847d4}.category-card h3{margin:3px 0 6px}.category-card p{font-size:14px;color:var(--muted);margin-bottom:10px}.category-card span{font-size:12px;font-weight:800;color:var(--muted)}.soft-section{background:var(--surface2);border-block:1px solid var(--line)}.popular-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:12px}.popular-card{border:1px solid var(--line);background:var(--surface);border-radius:18px;padding:16px;display:grid;grid-template-columns:auto 1fr auto;gap:12px;align-items:center}.popular-card:hover{border-color:var(--primary)}.popular-card div{display:flex;flex-direction:column}.popular-card strong{font-size:16px}.popular-card small{font-size:13px;color:var(--muted);margin-top:3px}.popular-card b{color:var(--muted)}.about-home-grid{display:grid;grid-template-columns:1fr 1fr;gap:70px}.about-home-grid>div:first-child>p{color:var(--muted);font-size:17px}.primary-link,.text-link{color:var(--primary);font-weight:850}.principles{display:grid;gap:12px}.principles div{border:1px solid var(--line);border-radius:18px;padding:18px;background:var(--surface);display:grid;grid-template-columns:auto 1fr;column-gap:14px}.principles b{grid-row:1/3;width:35px;height:35px;border-radius:11px;display:grid;place-items:center;background:var(--soft);color:var(--primary);font-size:11px}.principles p{color:var(--muted);font-size:13px;margin:4px 0 0}.cta-panel{border-radius:28px;padding:34px;background:linear-gradient(135deg,var(--primary),#7c54dd);color:#fff;display:flex;align-items:center;justify-content:space-between;gap:30px}.cta-panel .eyebrow{color:#dadcff}.cta-panel h2{margin:4px 0 8px}.cta-panel p{opacity:.8;margin:0}.primary-btn-link{display:inline-flex;align-items:center;justify-content:center;min-height:48px;padding:0 18px;border-radius:13px;background:#fff;color:#373cb5;font-weight:850;white-space:nowrap}.as-button{border:0;cursor:pointer}
.breadcrumb{display:flex;gap:8px;align-items:center;color:var(--muted);font-size:12px;padding-top:24px}.breadcrumb a:hover{color:var(--primary)}.calculator-hero{padding:34px 0 22px}.calculator-heading{display:grid;grid-template-columns:auto 1fr;gap:18px;align-items:start;max-width:850px}.calculator-heading h1{font-size:clamp(36px,5vw,56px);margin:5px 0 10px}.calculator-heading p{font-size:17px;color:var(--muted);margin:0}.trust-row{display:flex;gap:9px;flex-wrap:wrap;margin:22px 0 0 70px}.trust-row span,.privacy-chip,.updated-badge{font-size:11px;font-weight:800;padding:7px 10px;border-radius:999px;background:var(--surface2);color:var(--muted);border:1px solid var(--line)}.updated-badge{display:inline-flex;margin-top:12px;background:#e8f7ef;color:#167453;border-color:#ccebdd}.calc-layout{display:grid;grid-template-columns:minmax(0,1fr) 315px;gap:28px;padding:20px 0 72px}.calc-main{min-width:0}.calculator-card,.content-card,.feedback-card,.sidebar-card,.sidebar-note{background:var(--surface);border:1px solid var(--line);border-radius:22px;box-shadow:0 6px 24px rgba(25,31,55,.035)}.calculator-card{padding:24px}.card-heading,.content-heading{display:flex;align-items:center;justify-content:space-between;gap:18px;margin-bottom:20px}.card-heading h2,.content-heading h2{font-size:25px;margin:4px 0 0}.content-card{padding:26px;margin-top:18px}.visual-grid{display:grid;grid-template-columns:minmax(260px,.85fr) 1.15fr;gap:28px;align-items:center}.shape-figure{background:var(--surface2);border:1px solid var(--line);border-radius:18px;padding:12px}.shape-figure svg{width:100%;height:auto;display:block}.shape-line{stroke:var(--text);stroke-width:2.4;fill:none;stroke-linejoin:round}.shape-fill{stroke:var(--primary);stroke-width:2.6;fill:color-mix(in srgb,var(--primary) 9%,transparent);stroke-linejoin:round}.shape-soft{stroke:var(--primary);stroke-width:2.2;fill:color-mix(in srgb,var(--primary) 5%,transparent)}.shape-accent{stroke:var(--primary);stroke-width:3;fill:none}.shape-dash{stroke:var(--muted);stroke-width:1.6;stroke-dasharray:6 5;fill:none}.shape-label{fill:var(--text);font-size:15px;font-weight:850}.none{fill:none}.formula-visual{background:linear-gradient(145deg,var(--surface2),var(--soft));border:1px solid var(--line);border-radius:18px;padding:24px;min-height:190px;display:flex;flex-direction:column;justify-content:center}.formula-big{font-family:ui-monospace,SFMono-Regular,Menlo,monospace;font-size:22px;font-weight:900;color:var(--primary);margin:12px 0}.formula-visual p,.formula-copy>p,.supporting-copy{color:var(--muted)}.formula-static{font-family:ui-monospace,SFMono-Regular,Menlo,monospace;font-size:18px;font-weight:850;padding:14px 16px;background:var(--surface2);border:1px solid var(--line);border-radius:14px}.example-box{margin-top:18px;padding:15px 16px;border-left:3px solid var(--primary);background:var(--soft);border-radius:0 14px 14px 0}.example-box p{margin:4px 0 0;color:var(--muted)}.dynamic-formula .formula{margin-top:18px}.steps-list{list-style:none;padding:0;margin:0;display:grid;gap:12px}.steps-list li{display:grid;grid-template-columns:auto 1fr;gap:13px;align-items:start}.steps-list li>span{width:30px;height:30px;border-radius:9px;background:var(--soft);color:var(--primary);display:grid;place-items:center;font-size:12px;font-weight:900}.steps-list p{margin:2px 0;color:var(--muted)}.faq-list-v4{display:grid;gap:8px}.faq-list-v4 details{border:1px solid var(--line);border-radius:14px;padding:0 15px;background:var(--bg)}.faq-list-v4 summary{font-weight:800;cursor:pointer;padding:14px 0;list-style:none}.faq-list-v4 summary::-webkit-details-marker{display:none}.faq-list-v4 p{color:var(--muted);padding-bottom:14px;margin:0}.source-links{display:grid;gap:8px}.source-links a{padding:11px 12px;border:1px solid var(--line);border-radius:12px;color:var(--primary);font-weight:750}.feedback-card{margin-top:18px;padding:24px;display:flex;align-items:center;justify-content:space-between;gap:24px}.feedback-card h2{font-size:22px;margin:4px 0}.feedback-card p{color:var(--muted);font-size:13px;margin:0}.feedback-actions{display:flex;gap:7px}.feedback-actions button{border:1px solid var(--line);background:var(--bg);color:#e5a000;border-radius:13px;padding:9px 11px;cursor:pointer;font-size:14px;font-weight:900}.feedback-actions button small{display:block;color:var(--muted);font-size:9px;font-weight:700}.feedback-actions button:hover{border-color:#e5a000;background:#fff9e5}.feedback-thanks{font-weight:800;color:var(--good)}.calc-sidebar{display:grid;align-content:start;gap:16px}.sidebar-card{padding:19px;position:sticky;top:92px}.sidebar-card+ .sidebar-card{position:static}.formula-side-value{font-family:ui-monospace,SFMono-Regular,Menlo,monospace;font-weight:850;color:var(--primary);padding:12px;background:var(--surface2);border-radius:12px;margin:10px 0 12px;font-size:12px}.related-stack{display:grid;gap:8px}.related-card{display:grid;grid-template-columns:auto 1fr auto;align-items:center;gap:9px;border-top:1px solid var(--line);padding:10px 0}.related-card>span{width:30px;height:30px;border-radius:9px;display:grid;place-items:center;background:var(--soft);color:var(--primary);font-size:10px;font-weight:850}.related-card div{display:flex;flex-direction:column}.related-card strong{font-size:14px}.related-card small{font-size:10px;color:var(--muted);display:none}.related-card b{color:var(--muted)}.sidebar-note{padding:17px}.sidebar-note p{font-size:13px;color:var(--muted);margin:4px 0 0}.sidebar-note a{color:var(--primary)}
/* calculator UI retained */.form-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:14px}.field{display:flex;flex-direction:column;gap:6px}.field.full{grid-column:1/-1}.field label{font-size:12px;font-weight:800}.field input,.field select,.field textarea{width:100%;border:1px solid var(--line);background:var(--bg);color:var(--text);border-radius:13px;padding:13px 14px;outline:0}.field textarea{min-height:180px;resize:vertical;font-family:ui-monospace,SFMono-Regular,Menlo,monospace}.field input:focus,.field select:focus,.field textarea:focus{border-color:var(--primary);box-shadow:0 0 0 3px color-mix(in srgb,var(--primary) 12%,transparent)}.field small{font-size:10px;color:var(--muted)}.calc-actions{display:flex;gap:9px;margin-top:18px}.primary-btn,.secondary-btn{min-height:44px;border-radius:12px;padding:0 16px;font-weight:850;cursor:pointer}.primary-btn{border:0;background:var(--primary);color:#fff}.primary-btn:hover{background:var(--primary2)}.secondary-btn{border:1px solid var(--line);background:var(--surface2);color:var(--text)}.result-panel{background:#171b33;color:#fff;border-radius:18px;padding:20px;margin-top:18px}.result-label{font-size:10px;text-transform:uppercase;letter-spacing:.12em;color:#aeb6d7;font-weight:800}.result-main{font-size:31px;line-height:1.15;font-weight:900;letter-spacing:-.04em;margin:5px 0 12px}.result-main.small{font-size:20px}.result-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:7px}.result-row{background:rgba(255,255,255,.07);border-radius:11px;padding:9px 10px;display:flex;justify-content:space-between;gap:8px;font-size:12px}.result-row span{color:#aeb6d7}.calc-tabs{display:flex;gap:5px;background:var(--surface2);padding:5px;border-radius:13px;margin-bottom:16px;overflow:auto}.calc-tabs button{border:0;background:transparent;color:var(--muted);padding:8px 11px;border-radius:9px;font-weight:750;white-space:nowrap;cursor:pointer}.calc-tabs button.active{background:var(--surface);color:var(--text);box-shadow:0 2px 7px rgba(0,0,0,.06)}.formula{background:var(--surface2);border:1px solid var(--line);border-radius:13px;padding:13px 15px;font-family:ui-monospace,SFMono-Regular,Menlo,monospace;font-size:12px}.loading,.muted,.notice{color:var(--muted)}.error{color:var(--danger);font-size:13px}.check-row{display:flex;align-items:center;gap:8px;font-size:12px}.info-panel{border:1px solid var(--line);background:var(--surface2);border-radius:16px;padding:19px}.link-btn{display:inline-flex;min-height:44px;align-items:center;padding:0 15px;border-radius:12px;background:var(--primary);color:#fff;font-weight:800}.sudoku-output{white-space:pre;font-family:ui-monospace,SFMono-Regular,Menlo,monospace;line-height:1.55}.hidden{display:none!important}
.category-hero,.page-hero{padding:55px 0 46px;background:linear-gradient(180deg,var(--surface),var(--bg));border-bottom:1px solid var(--line)}.category-title{display:grid;grid-template-columns:auto 1fr;gap:18px;align-items:start;margin-top:24px;max-width:850px}.category-title h1,.page-hero h1{font-size:clamp(38px,5vw,58px);margin:4px 0 12px}.category-title p,.page-hero p{color:var(--muted);font-size:17px}.category-tip{margin-top:25px;max-width:900px;padding:16px 18px;background:var(--soft);border-radius:16px;border:1px solid color-mix(in srgb,var(--primary) 15%,var(--line))}.category-tip p{color:var(--muted);margin:4px 0 0}.secondary-action{border:1px solid var(--line);background:var(--surface);color:var(--text);border-radius:12px;padding:10px 14px;font-weight:800;cursor:pointer}.calc-list-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:10px}.calc-list-card{display:grid;grid-template-columns:auto 1fr auto;gap:13px;align-items:center;border:1px solid var(--line);background:var(--surface);border-radius:17px;padding:15px}.calc-list-card:hover{border-color:var(--primary);transform:translateY(-1px)}.calc-list-card div{display:flex;flex-direction:column}.calc-list-card strong{font-size:16px}.calc-list-card small{font-size:13px;color:var(--muted)}.calc-list-card em{font-family:ui-monospace,SFMono-Regular,Menlo,monospace;font-size:12px;color:var(--primary);font-style:normal;margin-top:5px}.calc-badge{width:44px;height:44px;border-radius:11px;display:grid;place-items:center;background:var(--soft);color:var(--primary);font-size:11px;font-weight:900}.formula-library-section{margin-bottom:55px}.formula-library-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:12px}.formula-library-card{border:1px solid var(--line);background:var(--surface);border-radius:17px;padding:17px;display:flex;flex-direction:column}.formula-library-card>span{font-weight:850;font-size:15px}.formula-library-card code{color:var(--primary);font-weight:850;margin:9px 0;font-size:15px}.formula-library-card small{color:var(--muted);font-size:13px}.prose-v4{font-size:17px}.prose-v4 h2{margin-top:38px}.prose-v4 p{color:var(--muted)}.prose-v4 a{color:var(--primary);font-weight:750}.not-found{min-height:62vh;display:grid;place-items:center;text-align:center}.not-found-card{max-width:620px}.not-found-code{font-size:78px;font-weight:950;letter-spacing:-.07em;color:var(--primary)}.not-found-card .text-link{display:block;margin-top:20px}
.site-footer{background:#111427;color:#fff;margin-top:20px;padding:52px 0 20px}.footer-grid{display:grid;grid-template-columns:1.6fr repeat(3,1fr);gap:42px}.footer-grid>div{display:flex;flex-direction:column;align-items:flex-start;gap:9px}.footer-grid p,.footer-grid a,.footer-grid span{color:#aeb5d0;font-size:12px}.footer-grid a:hover{color:#fff}.footer-brand{color:#fff}.footer-grid strong{font-size:12px}.footer-bottom{display:flex;justify-content:space-between;gap:20px;border-top:1px solid rgba(255,255,255,.1);margin-top:34px;padding-top:18px;color:#818aa9;font-size:11px}
/* global search overlay */.header-search-btn{font-size:23px}.mobile-menu-btn{display:none;font-size:18px}.modal-open{overflow:hidden}.site-search-overlay{position:fixed;inset:0;z-index:100;background:rgba(8,13,24,.58);backdrop-filter:blur(9px);padding:88px 20px 20px;overflow:auto}.site-search-overlay[hidden]{display:none!important}.site-search-dialog{width:min(680px,100%);margin:auto;background:var(--surface);border:1px solid var(--line);border-radius:24px;box-shadow:0 30px 90px rgba(0,0,0,.3);padding:18px}.site-search-top{display:flex;align-items:center;justify-content:space-between;margin-bottom:14px}.global-search-box{height:58px;border:1px solid var(--line);background:var(--bg);border-radius:16px;display:flex;align-items:center;gap:10px;padding:0 15px}.global-search-box input{border:0;outline:0;background:transparent;color:var(--text);width:100%}.global-search-results{padding-top:9px}.global-search-hint{padding:18px 12px;color:var(--muted);font-size:13px}.mobile-nav-links{display:none;border-top:1px solid var(--line);margin-top:10px;padding-top:10px}.mobile-nav-links a{padding:10px 8px;border-radius:9px;font-weight:750;font-size:13px}
/* No visible empty ad placeholders before approval. Auto Ads may use the AdSense site script after approval. */.ad-shell,.ad-reserve{display:none!important}
@media(max-width:1000px){.formula-grid{grid-template-columns:repeat(3,1fr)}.category-grid{grid-template-columns:repeat(2,1fr)}.popular-grid{grid-template-columns:repeat(2,1fr)}.calc-layout{grid-template-columns:1fr}.calc-sidebar{grid-template-columns:1fr 1fr}.sidebar-card{position:static}.hero-grid{gap:35px}.formula-library-grid{grid-template-columns:repeat(2,1fr)}}
@media(max-width:820px){.main-nav{display:none}.mobile-menu-btn{display:grid}.header-inner{gap:8px}.brand{margin-right:auto}.hero-grid{grid-template-columns:1fr}.hero-panel{display:none}.about-home-grid{grid-template-columns:1fr;gap:35px}.visual-grid{grid-template-columns:1fr}.footer-grid{grid-template-columns:1fr 1fr}.footer-grid>div:first-child{grid-column:1/-1}.mobile-nav-links{display:flex;flex-direction:column}.feedback-card{align-items:flex-start;flex-direction:column}.calc-sidebar{grid-template-columns:1fr}}
@media(max-width:620px){.wrap{width:min(var(--max),calc(100% - 24px))}.site-header{height:64px}.header-search-btn{display:none}.hero{padding:55px 0}.hero h1{font-size:45px}.hero-copy{font-size:16px}.search-box{height:56px}.search-box kbd{display:none}.formula-grid,.category-grid,.popular-grid,.calc-list-grid,.formula-library-grid{grid-template-columns:1fr}.section{padding:50px 0}.section-head{align-items:flex-start;flex-direction:column}.formula-strip{padding:38px 0}.calculator-heading{grid-template-columns:1fr}.calculator-heading .calc-symbol{width:46px;height:46px}.trust-row{margin-left:0}.calculator-card,.content-card,.feedback-card{padding:18px}.card-heading{align-items:flex-start;flex-direction:column}.form-grid,.result-grid{grid-template-columns:1fr}.field.full{grid-column:auto}.calc-actions{flex-wrap:wrap}.feedback-actions{width:100%;display:grid;grid-template-columns:repeat(3,1fr)}.feedback-actions button{padding-inline:5px}.footer-grid{grid-template-columns:1fr}.footer-grid>div:first-child{grid-column:auto}.footer-bottom{flex-direction:column}.cta-panel{align-items:flex-start;flex-direction:column}.formula-library{padding-top:40px}.site-search-overlay{padding:68px 10px 10px}.site-search-dialog{border-radius:20px;padding:14px}.home-search-results{width:calc(100% - 24px)}}

/* V4.1 readability tuning */
.home-search-result strong,.global-search-result strong{font-size:15px}.calc-list-card{padding:18px 17px;gap:15px}.formula-card{padding:18px 16px;gap:7px}.popular-card{padding:18px}.category-card{padding:24px}.formula-library-card{padding:19px}.feedback-card p{font-size:14px}

/* V4.2 content-quality and readability pass */
.content-heading{align-items:flex-start;justify-content:flex-start;flex-direction:column;gap:2px}
.content-heading h2{text-align:left}
.formula-runtime-hidden{display:none!important}
.shape-label{font-size:18px;font-weight:900}
.symbol-legend{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:8px;margin-top:12px}
.symbol-legend>div{display:flex;align-items:center;gap:9px;padding:8px 10px;border:1px solid var(--line);border-radius:11px;background:var(--bg)}
.symbol-legend code{min-width:32px;color:var(--primary);font-weight:900;font-size:14px}
.symbol-legend span{font-size:13px;color:var(--muted);line-height:1.3}
.attention-note{margin:16px 0;padding:13px 15px;border:1px solid color-mix(in srgb,var(--primary) 22%,var(--line));background:color-mix(in srgb,var(--primary) 5%,var(--bg));border-radius:13px}
.attention-note strong{display:block;font-size:13px;margin-bottom:3px}
.attention-note p{margin:0!important;color:var(--muted)}
.worked-example-line{font-family:ui-monospace,SFMono-Regular,Menlo,monospace;font-weight:800;font-size:13px;margin-top:9px;padding:9px 11px;border-radius:10px;background:var(--bg);border:1px solid var(--line);overflow-wrap:anywhere}
.quick-nav-card h3{margin-bottom:12px}
.page-jumps{display:grid}
.page-jumps a{display:grid;grid-template-columns:30px 1fr auto;align-items:center;gap:9px;padding:11px 0;border-top:1px solid var(--line)}
.page-jumps a:first-child{border-top:0}
.page-jumps a>span{width:28px;height:28px;border-radius:9px;background:var(--soft);color:var(--primary);display:grid;place-items:center;font-size:10px;font-weight:900}
.page-jumps a>strong{font-size:14px}
.page-jumps a>b{color:var(--primary);font-size:12px}
.steps-list p{font-size:16px;line-height:1.6}
.faq-list-v4 summary{font-size:15px;line-height:1.45}
.faq-list-v4 details p{font-size:15px;line-height:1.6}
.formula-copy>p{font-size:16px;line-height:1.65}
.example-box p{font-size:15px;line-height:1.55}
@media(max-width:640px){
  .symbol-legend{grid-template-columns:1fr}
  .shape-label{font-size:19px}
  .steps-list p,.formula-copy>p{font-size:15px}
}

/* V5.3 content hardening */
.static-calc-fallback{display:block}.static-calc-note{margin:14px 0 0;color:var(--muted);font-size:14px;line-height:1.65}.reviewed-line{margin:10px 0 0!important;font-size:13px!important;font-weight:700;color:var(--muted)!important}.parameter-panel{margin-top:22px;padding-top:22px;border-top:1px solid var(--line)}.parameter-panel h3{margin:0 0 12px;font-size:18px}.parameter-table{width:100%;border-collapse:collapse;font-size:14px}.parameter-table th,.parameter-table td{padding:11px 12px;border:1px solid var(--line);text-align:left;vertical-align:top}.parameter-table th{background:var(--soft);font-size:12px;text-transform:uppercase;letter-spacing:.06em}.consolidation-note{padding:16px 18px;margin:0 0 20px;border:1px solid var(--line);border-left:4px solid var(--primary);border-radius:14px;background:var(--soft)}.consolidation-note p{margin:6px 0 0;color:var(--muted);line-height:1.7}.guide-hero{padding:64px 0 34px}.guide-hero h1{font-size:clamp(38px,6vw,68px);line-height:1.02;max-width:900px;margin:10px 0 18px}.guide-hero p{max-width:820px;font-size:18px;line-height:1.75;color:var(--muted)}.guide-meta{display:flex;gap:10px;flex-wrap:wrap;margin-top:18px}.guide-meta span{padding:7px 10px;border:1px solid var(--line);border-radius:999px;font-size:12px;font-weight:700}.guide-layout{display:grid;grid-template-columns:minmax(0,1fr) 300px;gap:28px;align-items:start;padding-bottom:80px}.guide-article{display:grid;gap:20px}.guide-article .content-card h2{font-size:28px;margin-top:0}.guide-article .content-card h3{font-size:20px;margin-top:24px}.guide-article p,.guide-article li{line-height:1.8;color:var(--text)}.guide-article ul,.guide-article ol{padding-left:22px}.guide-example{padding:18px;border-radius:14px;background:var(--soft);border:1px solid var(--line);margin:16px 0}.guide-example strong{display:block;margin-bottom:8px}.guide-table{width:100%;border-collapse:collapse;margin:16px 0;font-size:14px}.guide-table th,.guide-table td{padding:11px;border:1px solid var(--line);text-align:left}.guide-table th{background:var(--soft)}.guide-index-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:16px}.guide-card{display:block;padding:22px;border:1px solid var(--line);border-radius:20px;background:var(--card);text-decoration:none;color:inherit}.guide-card:hover{transform:translateY(-2px);box-shadow:var(--shadow)}.guide-card span{font-size:12px;text-transform:uppercase;letter-spacing:.08em;color:var(--primary);font-weight:800}.guide-card h3{margin:8px 0}.guide-card p{margin:0;color:var(--muted);line-height:1.65}.source-list{display:grid;gap:10px}.source-list a{display:block;padding:12px 14px;border:1px solid var(--line);border-radius:12px;text-decoration:none}.home-guides{margin-top:26px}.home-guide-grid{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:14px}.home-guide-grid a{padding:18px;border:1px solid var(--line);border-radius:18px;background:var(--card);text-decoration:none;color:inherit}.home-guide-grid strong{display:block;margin-bottom:6px}.home-guide-grid span{font-size:13px;color:var(--muted);line-height:1.5}.legacy-note{padding:16px 18px;border-radius:14px;background:var(--soft);border:1px solid var(--line)}
@media(max-width:900px){.guide-layout{grid-template-columns:1fr}.guide-sidebar{display:none}.home-guide-grid{grid-template-columns:1fr 1fr}.guide-index-grid{grid-template-columns:1fr}}
@media(max-width:560px){.home-guide-grid{grid-template-columns:1fr}.parameter-table{font-size:12px}.parameter-table th,.parameter-table td{padding:8px}.guide-hero{padding-top:36px}}

/* V5.3 — editorial depth + lightweight 3D */
.editorial-home{overflow:hidden}.editorial-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:16px}.editorial-grid article{position:relative;min-width:0;border:1px solid var(--line);border-radius:22px;background:var(--surface);padding:24px;overflow:hidden}.editorial-grid article>span{display:inline-grid;place-items:center;width:38px;height:38px;border-radius:12px;background:var(--soft);color:var(--primary);font-size:11px;font-weight:900;margin-bottom:18px}.editorial-grid article h3{margin-bottom:8px}.editorial-grid article p{margin:0;color:var(--muted);font-size:14px}.editorial-process{margin-top:24px}.category-depth{padding-top:0}.category-depth .content-card{max-width:920px;margin-inline:auto}.category-depth p{color:var(--muted);font-size:16px}.context-card .context-grid{display:grid;grid-template-columns:1fr 1fr;gap:16px}.context-card .context-grid>div{border:1px solid var(--line);background:var(--surface2);border-radius:18px;padding:20px}.context-card h3{margin:0 0 9px;font-size:18px}.context-card p{margin:0;color:var(--muted)}.sanity-check{margin-top:16px;border-left:3px solid var(--primary);background:color-mix(in srgb,var(--soft) 72%,var(--surface));border-radius:0 16px 16px 0;padding:18px 20px}.sanity-check strong{display:block;margin-bottom:7px}.sanity-check ul{margin:0;padding-left:19px;color:var(--muted)}.sanity-check li+li{margin-top:5px}.method-links{display:flex;flex-direction:column;gap:7px;margin-top:12px}.method-links a{color:var(--primary);font-weight:800;font-size:13px}.guide-index-card h2{font-size:clamp(22px,2.4vw,30px)}

.hero-panel{position:relative;overflow:hidden;transform-style:preserve-3d;perspective:900px;transition:transform .18s ease-out}.hero-panel>*:not(.hero-3d-scene){position:relative;z-index:2}.hero-3d-scene{height:185px;position:relative;margin:-8px 0 18px;perspective:800px;pointer-events:none}.hero-cube{position:absolute;width:72px;height:72px;left:50%;top:48%;transform-style:preserve-3d;animation:heroCubeSpin 13s linear infinite;transform:translate(-50%,-50%) rotateX(-18deg) rotateY(25deg)}.cube-face{position:absolute;inset:0;display:grid;place-items:center;border:1px solid rgba(255,255,255,.26);background:linear-gradient(145deg,rgba(255,255,255,.16),rgba(255,255,255,.045));backdrop-filter:blur(5px);font-size:23px;font-weight:900;color:#fff}.cf-front{transform:translateZ(36px)}.cf-back{transform:rotateY(180deg) translateZ(36px)}.cf-left{transform:rotateY(-90deg) translateZ(36px)}.cf-right{transform:rotateY(90deg) translateZ(36px)}.cf-top{transform:rotateX(90deg) translateZ(36px)}.cf-bottom{transform:rotateX(-90deg) translateZ(36px)}.orbit-card{position:absolute;padding:7px 10px;border:1px solid rgba(255,255,255,.14);border-radius:10px;background:rgba(255,255,255,.075);color:#dbe0ff;font:800 10px/1.2 ui-monospace,SFMono-Regular,Menlo,monospace;box-shadow:0 10px 25px rgba(0,0,0,.12);animation:orbitFloat 5.5s ease-in-out infinite}.orbit-a{left:7%;top:18%;transform:rotate(-7deg)}.orbit-b{right:3%;top:29%;animation-delay:-1.7s;transform:rotate(7deg)}.orbit-c{left:16%;bottom:5%;animation-delay:-3.1s;transform:rotate(3deg)}@keyframes heroCubeSpin{0%{transform:translate(-50%,-50%) rotateX(-18deg) rotateY(0deg)}100%{transform:translate(-50%,-50%) rotateX(-18deg) rotateY(360deg)}}@keyframes orbitFloat{0%,100%{translate:0 0}50%{translate:0 -8px}}

.model3d-card{overflow:hidden}.model3d-layout{display:grid;grid-template-columns:minmax(260px,1.05fr) minmax(240px,.95fr);gap:28px;align-items:center}.model3d-stage{position:relative;min-height:300px;border:1px solid var(--line);border-radius:22px;background:radial-gradient(circle at 50% 35%,color-mix(in srgb,var(--primary) 12%,var(--surface)),var(--surface2) 68%);perspective:850px;display:grid;place-items:center;overflow:hidden;touch-action:pan-y;outline:none}.model3d-stage:focus-visible{box-shadow:0 0 0 3px color-mix(in srgb,var(--primary) 25%,transparent)}.model3d-object{position:relative;width:150px;height:150px;transform-style:preserve-3d;transform:rotateX(-18deg) rotateY(28deg);transition:transform .12s ease-out;z-index:2}.model3d-stage.is-auto .model3d-object{animation:modelSpin 12s linear infinite}.model3d-floor{position:absolute;width:210px;height:72px;border-radius:50%;background:radial-gradient(ellipse,rgba(44,52,93,.18),transparent 68%);bottom:28px;transform:rotateX(68deg)}@keyframes modelSpin{0%{transform:rotateX(-18deg) rotateY(0deg)}100%{transform:rotateX(-18deg) rotateY(360deg)}}.model3d-copy p{color:var(--muted)}.model3d-actions{display:flex;gap:9px;flex-wrap:wrap}.model3d-actions button{min-height:43px;border:1px solid var(--line);border-radius:12px;background:var(--surface);color:var(--text);padding:0 14px;font-weight:800;cursor:pointer}.model3d-actions button:hover{border-color:var(--primary);color:var(--primary)}
.box3d{position:absolute;width:112px;height:112px;left:19px;top:19px;transform-style:preserve-3d}.box3d .face{position:absolute;inset:0;border:2px solid color-mix(in srgb,var(--primary) 65%,var(--text));background:color-mix(in srgb,var(--primary) 12%,transparent);backface-visibility:visible}.box3d .front{transform:translateZ(56px)}.box3d .back{transform:rotateY(180deg) translateZ(56px)}.box3d .left{transform:rotateY(-90deg) translateZ(56px)}.box3d .right{transform:rotateY(90deg) translateZ(56px)}.box3d .top{transform:rotateX(90deg) translateZ(56px)}.box3d .bottom{transform:rotateX(-90deg) translateZ(56px)}.model3d-object.box-wide .box3d{transform:scaleX(1.32) scaleY(.78)}.model3d-object.box-tall .box3d{transform:scaleX(.9) scaleY(1.28)}
.pyramid3d{position:absolute;inset:12px;transform-style:preserve-3d}.p-base{position:absolute;width:110px;height:110px;left:8px;top:72px;border:2px solid var(--primary);background:color-mix(in srgb,var(--primary) 9%,transparent);transform:rotateX(90deg) translateZ(-25px)}.p-side{position:absolute;width:110px;height:112px;left:8px;top:8px;clip-path:polygon(50% 0,100% 100%,0 100%);border-bottom:2px solid var(--primary);background:linear-gradient(145deg,color-mix(in srgb,var(--primary) 22%,transparent),transparent);transform-origin:50% 100%}.p1{transform:rotateY(0deg) rotateX(28deg) translateZ(35px)}.p2{transform:rotateY(90deg) rotateX(28deg) translateZ(35px)}.p3{transform:rotateY(180deg) rotateX(28deg) translateZ(35px)}.p4{transform:rotateY(270deg) rotateX(28deg) translateZ(35px)}
.sphere3d{position:absolute;width:126px;height:126px;left:12px;top:12px;transform-style:preserve-3d}.sphere-core{position:absolute;inset:8px;border-radius:50%;border:2px solid var(--primary);background:radial-gradient(circle at 35% 30%,color-mix(in srgb,var(--primary) 28%,var(--surface)),color-mix(in srgb,var(--primary) 7%,var(--surface2)) 62%)}.s-ring{position:absolute;inset:8px;border:2px solid color-mix(in srgb,var(--primary) 60%,transparent);border-radius:50%}.r1{transform:rotateX(70deg)}.r2{transform:rotateY(70deg)}.r3{transform:rotateY(45deg) rotateX(65deg)}
.cylinder3d{position:absolute;width:100px;height:132px;left:25px;top:9px;transform-style:preserve-3d}.c-body{position:absolute;left:8px;right:8px;top:18px;bottom:18px;border-inline:2px solid var(--primary);background:linear-gradient(90deg,color-mix(in srgb,var(--primary) 7%,transparent),color-mix(in srgb,var(--primary) 18%,transparent),color-mix(in srgb,var(--primary) 7%,transparent))}.c-cap{position:absolute;left:8px;width:84px;height:30px;border:2px solid var(--primary);border-radius:50%;background:color-mix(in srgb,var(--primary) 10%,var(--surface))}.c-cap.top{top:4px}.c-cap.bottom{bottom:4px}.c-line{position:absolute;top:19px;bottom:19px;width:2px;background:color-mix(in srgb,var(--primary) 40%,transparent)}.c-line.l1{left:22px}.c-line.l2{right:22px}
.cone3d{position:absolute;width:118px;height:140px;left:16px;top:4px;transform-style:preserve-3d}.cone-side{position:absolute;width:112px;height:118px;left:3px;top:2px;clip-path:polygon(50% 0,93% 100%,7% 100%);background:linear-gradient(90deg,color-mix(in srgb,var(--primary) 6%,transparent),color-mix(in srgb,var(--primary) 22%,transparent),color-mix(in srgb,var(--primary) 6%,transparent));border-bottom:2px solid var(--primary)}.cone-base{position:absolute;width:96px;height:28px;left:11px;bottom:4px;border:2px solid var(--primary);border-radius:50%;background:color-mix(in srgb,var(--primary) 10%,var(--surface))}.cone-axis{position:absolute;width:2px;height:108px;left:58px;top:12px;background:linear-gradient(var(--primary),transparent)}

@media(max-width:900px){.editorial-grid{grid-template-columns:1fr}.context-card .context-grid,.model3d-layout{grid-template-columns:1fr}.model3d-stage{min-height:260px}.hero-3d-scene{height:150px}}
@media(max-width:640px){.context-card .context-grid{gap:10px}.context-card .context-grid>div{padding:16px}.model3d-actions button{flex:1 1 auto}.hero-3d-scene{height:135px}.orbit-card{font-size:9px}.hero-cube{scale:.86}.editorial-grid article{padding:20px}}
@media(prefers-reduced-motion:reduce){.hero-cube,.orbit-card,.model3d-stage.is-auto .model3d-object{animation:none!important}.hero-panel{transition:none}.model3d-object{transition:none}}
.guide-toc{display:grid;gap:5px}.guide-toc a{display:grid;grid-template-columns:30px 1fr;gap:8px;align-items:start;padding:8px 0;border-bottom:1px solid var(--line);font-size:13px}.guide-toc a:last-child{border-bottom:0}.guide-toc span{color:var(--primary);font-size:10px;font-weight:900;padding-top:3px}.guide-toc strong{line-height:1.35}.guide-related-links{display:grid;grid-template-columns:repeat(3,1fr);gap:10px}.guide-related-links a{display:flex;justify-content:space-between;gap:12px;border:1px solid var(--line);border-radius:14px;padding:13px;font-size:13px;font-weight:800;background:var(--surface2)}.guide-related-links a:hover{border-color:var(--primary);color:var(--primary)}.guide-promo-card{background:linear-gradient(145deg,color-mix(in srgb,var(--soft) 75%,var(--surface)),var(--surface))}.v53-interactive{transition:transform .18s ease,border-color .18s ease,box-shadow .18s ease}.v53-interactive:active{transform:translateY(1px) scale(.995)}
@media(max-width:700px){.guide-related-links{grid-template-columns:1fr}}