/* Scientific Tools · v8. Shared visual language, light and dark themes. No external fonts. */
:root{--paper:#f3f6fa;--ink:#182f43;--muted:#536c80;--line:#cddce8;--accent:#245cba;--panel:#fff;--soft:#e9f0f8;--control-bg:#fff;--focus:#895211;--tech:Bahnschrift,'DIN Alternate','Aptos','Segoe UI',Arial,sans-serif;--mono:'Cascadia Code','SFMono-Regular',Consolas,monospace;color-scheme:light}
html[data-theme=dark]{--paper:#0d1520;--ink:#e6eff7;--muted:#aabdd0;--line:#30485f;--accent:#9dcbff;--panel:#142233;--soft:#1a2d43;--control-bg:#1a2b3e;--focus:#efca87;color-scheme:dark}
*{box-sizing:border-box}html{scroll-padding-top:115px;scroll-behavior:smooth}body{margin:0;color:var(--ink);background:radial-gradient(ellipse 900px 500px at 95% -70px,#6486e011,transparent 70%),var(--paper);font:16px/1.65 var(--tech);-webkit-font-smoothing:antialiased}h1,h2,h3,p{margin:0}h1,h2,h3{font-weight:550;line-height:1.14}h1{font-size:clamp(36px,4.6vw,61px);letter-spacing:-.05em;max-width:900px}h2{font-size:30px;letter-spacing:-.025em}h3{font-size:22px;letter-spacing:-.02em}a{color:var(--accent);text-underline-offset:4px;text-decoration-thickness:1px}a:hover{text-decoration:none}a,button{touch-action:manipulation}button,input,select,textarea{font:inherit}button{cursor:pointer}button,a,input,select,textarea,summary{outline-offset:4px}:focus-visible{outline:2px solid var(--focus)}img{max-width:100%;display:block}button svg{pointer-events:none}button:disabled{opacity:.45;cursor:not-allowed}[hidden]{display:none!important}.wrap{width:min(1216px,calc(100% - 80px));margin-inline:auto}.sr-only{position:absolute;width:1px;height:1px;overflow:hidden;clip-path:inset(50%);white-space:nowrap}.skip{position:absolute;top:10px;left:10px;z-index:100;background:var(--panel);padding:12px;transform:translateY(-200%)}.skip:focus{transform:none}.icon{width:19px;height:19px;fill:none;stroke:currentColor;stroke-width:1.5;stroke-linecap:round;stroke-linejoin:round;vertical-align:middle;flex-shrink:0}
.site-header{position:sticky;top:12px;z-index:30;width:min(1376px,calc(100% - 40px));margin:12px auto 0;border:1px solid var(--line);background:color-mix(in srgb,var(--panel) 92%,transparent);backdrop-filter:blur(18px);border-radius:18px;box-shadow:0 6px 20px #16355206}.header-inner{display:flex;align-items:center;gap:28px;min-height:78px;padding:9px 24px}.brand{display:flex;align-items:center;gap:12px;text-decoration:none;color:var(--ink);margin-right:auto}.brand-logo-wrap{display:grid;place-items:center;width:70px;height:50px;background:white;border-radius:8px;padding:4px;flex-shrink:0}.brand-logo{width:100%;height:100%;object-fit:contain}.brand-name{font:600 22px/1.14 var(--tech);letter-spacing:-.045em;white-space:nowrap}.brand-point{color:var(--accent)}#primary-nav{display:flex;gap:27px;align-items:center;font-size:13px}#primary-nav a{color:var(--ink);text-decoration:none;min-height:44px;display:flex;align-items:center;border-bottom:2px solid transparent}#primary-nav a[aria-current]{color:var(--accent);border-color:var(--accent)}.header-actions{display:flex;gap:8px;align-items:center}.theme-toggle,.menu-toggle{background:var(--control-bg);color:var(--ink);border:1px solid var(--line);border-radius:999px;min-height:44px;padding:10px 13px;display:flex;align-items:center;gap:8px;font-size:12px}.theme-toggle .theme-sun{display:none}html[data-theme=dark] .theme-moon{display:none}html[data-theme=dark] .theme-sun{display:block}.menu-toggle{display:none}.eyebrow{font:11px/1.7 var(--mono);letter-spacing:.09em;text-transform:uppercase;color:var(--muted)}.breadcrumb{display:flex;gap:9px;flex-wrap:wrap;font-size:12px;margin-block:32px 24px;align-items:center}.breadcrumb a{color:var(--muted);text-decoration:none}.breadcrumb [aria-current]{color:var(--ink)}.tool-hero{padding-bottom:30px}.tool-hero .eyebrow{margin-bottom:12px}.tool-lead{color:var(--muted);max-width:750px;font-size:17px;line-height:1.75;margin-top:16px}.hero-meta{display:flex;flex-wrap:wrap;gap:10px 25px;margin-top:24px;font:11px/1.6 var(--mono);color:var(--muted)}.hero-meta span{display:flex;align-items:center;gap:7px}.status-dot{height:6px;width:6px;border-radius:50%;background:#408fa2}
.tool-index{display:grid;grid-template-columns:repeat(2,1fr);gap:22px;margin:12px 0 54px}.tool-card{padding:30px;border:1px solid var(--line);border-radius:20px;background:var(--panel);display:flex;flex-direction:column;position:relative;transition:transform .2s ease,border-color .2s ease;overflow:hidden;text-decoration:none;color:var(--ink);min-height:260px}.tool-card:hover{transform:translateY(-3px);border-color:var(--accent)}.tool-card h2{font-size:27px;max-width:420px;margin:23px 0 12px}.tool-card p{font-size:14px;color:var(--muted);max-width:440px;margin-bottom:20px}.tool-card .card-link{margin-top:auto;font:12px var(--mono);display:flex;justify-content:space-between;align-items:center;color:var(--accent)}.tool-equation{font:500 25px/1.5 var(--mono);color:var(--accent);display:flex;justify-content:space-between;align-items:center}.tool-equation small{font:11px var(--mono);color:var(--muted)}.tool-card:nth-child(2){background:linear-gradient(145deg,#9baef90c,#a0e8ed0a),var(--panel)}.method-callout{padding:28px 30px;border-block:1px solid var(--line);display:flex;gap:40px;align-items:center;justify-content:space-between;margin-bottom:55px}.method-callout p{color:var(--muted);font-size:14px;max-width:700px;margin-top:10px}.method-callout a{white-space:nowrap;font-size:13px}
.calculator-grid{display:grid;grid-template-columns:minmax(0,1.1fr) minmax(0,.9fr);gap:26px;align-items:start;margin:5px 0 60px}.calc-panel{background:var(--panel);border:1px solid var(--line);border-radius:20px;padding:29px;min-width:0}.panel-title{display:flex;justify-content:space-between;align-items:center;margin-bottom:25px;gap:20px}.panel-title h2{font-size:21px}.panel-title .eyebrow{font-size:10px}.fields{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:20px 18px}.field{display:flex;flex-direction:column;gap:7px;min-width:0}.field.wide,.wide{grid-column:1/-1}.field label{font-size:13px;color:var(--ink);font-weight:550}.field small,.field-note{font-size:11.5px;line-height:1.65;color:var(--muted)}input,select,textarea{width:100%;min-width:0;border:1px solid var(--line);border-radius:9px;background:var(--control-bg);color:var(--ink);min-height:49px;padding:11px 12px;font-size:15px}input[data-number]{font-family:var(--mono);font-size:16px}select{font-size:13px;padding-right:24px}textarea{resize:vertical;min-height:76px}input[aria-invalid=true]{border-color:#bd3939}.optional-label{font-size:11px;font-weight:400;color:var(--muted)}fieldset{padding:0;margin:0;border:0;min-width:0}fieldset legend{font-size:13px;font-weight:600;margin:5px 0 17px;color:var(--accent)}fieldset.groups{padding-top:23px;border-top:1px solid var(--line);margin-top:23px}.notice{padding:15px 17px;border:1px solid var(--line);border-radius:10px;background:var(--soft);color:var(--muted);font-size:12px;line-height:1.75;margin-top:22px}.notice strong{color:var(--ink);font-weight:600}.calc-actions{display:flex;flex-wrap:wrap;gap:10px;margin-top:25px}.action{display:inline-flex;align-items:center;justify-content:center;gap:10px;min-height:44px;border:1px solid var(--line);border-radius:999px;background:var(--control-bg);color:var(--ink);padding:10px 17px;font-size:12px;text-decoration:none}.action.primary{background:#255ba9;border-color:#255ba9;color:white}.action:hover:not(:disabled){border-color:var(--accent)}html[data-theme=dark] .action.primary{background:#9ccdf8;border-color:#9ccdf8;color:#102438}.examples{display:flex;gap:8px;flex-wrap:wrap;margin-top:18px}.examples button{border:0;background:transparent;color:var(--accent);font:11px var(--mono);text-decoration:underline;text-underline-offset:4px;min-height:32px;padding:4px 8px 4px 0}.error{color:#ab202e;font-size:13px;border-left:3px solid #ab202e;padding:10px 14px;background:#bd32320b;margin-top:18px}html[data-theme=dark] .error{color:#ffb7bb;border-color:#ffb7bb}.result-panel{position:sticky;top:116px;background:linear-gradient(145deg,#a0c9ff12,transparent 60%),var(--panel)}.readout{padding:9px 0 23px;border-bottom:1px solid var(--line)}.result-label{font:11px var(--mono);color:var(--muted);margin-bottom:12px}.result-value{font:500 clamp(32px,3.3vw,48px)/1.17 var(--tech);letter-spacing:-.045em;color:var(--accent);overflow-wrap:anywhere;font-variant-numeric:tabular-nums}.result-unit{font:12px/1.7 var(--mono);color:var(--muted);margin-top:8px;overflow-wrap:anywhere}.result-table{width:100%;border-collapse:collapse;font-size:12px;margin-top:14px}.result-table th,.result-table td{padding:12px 0;border-bottom:1px solid var(--line);text-align:left;vertical-align:top}.result-table th{font-weight:400;color:var(--muted);width:53%;padding-right:10px}.result-table td{text-align:right;font-family:var(--mono);color:var(--ink);overflow-wrap:anywhere}.result-warning{font-size:12px;line-height:1.8;color:var(--muted);margin-top:18px}.result-warning p+p{margin-top:8px}.result-warning .caution{border-left:2px solid #c19743;padding-left:12px;color:var(--ink)}.export-actions{display:flex;gap:8px;flex-wrap:wrap;margin-top:21px}.export-actions .action{font-size:11px;padding-inline:13px}.copy-feedback{font-size:12px;color:var(--accent);min-height:20px;margin-top:10px}.empty-result{font-size:14px;color:var(--muted);padding:24px 0}.precision-note{font-size:10px;line-height:1.6;color:var(--muted);margin-top:18px}.trace{background:var(--soft);padding:15px;border-radius:10px;font:11px/1.85 var(--mono);color:var(--ink);margin-top:17px;white-space:pre-wrap;overflow-wrap:anywhere}.copy-fallback{margin-top:15px}.copy-fallback label{font-size:11px;color:var(--muted)}
.method-layout{display:grid;grid-template-columns:minmax(0,1fr) 290px;gap:64px;align-items:start;padding:10px 0 60px;border-top:1px solid var(--line)}.prose{min-width:0}.prose h2{font-size:28px;margin:32px 0 16px}.prose h3{font-size:20px;margin:26px 0 12px}.prose p{font-size:14px;line-height:1.9;color:var(--muted);margin:13px 0}.prose strong{color:var(--ink)}.formula{font:15px/1.85 var(--mono);padding:18px 21px;border-left:2px solid var(--accent);background:var(--soft);margin:19px 0;overflow-wrap:anywhere}.prose .example{font-family:var(--mono);font-size:12px}.prose details{padding:18px 0;border-bottom:1px solid var(--line)}.prose summary{font-size:14px;cursor:pointer;color:var(--ink)}.prose table{border-collapse:collapse;width:100%;font-size:12px;line-height:1.7;margin:20px 0}.prose td,.prose th{padding:13px;border:1px solid var(--line);text-align:left;vertical-align:top}.prose th{font-weight:500;background:var(--soft)}.table-scroll{max-width:100%;overflow:auto}.aside-links{margin-top:35px;padding-left:25px;border-left:1px solid var(--line)}.aside-links h2{font-size:16px;margin-bottom:19px}.aside-links a{display:block;font-size:13px;padding:12px 0;border-bottom:1px solid var(--line);text-decoration:none}.aside-links p{font-size:11px;color:var(--muted);line-height:1.9;margin-top:18px}.source-list{padding-left:22px;margin:18px 0}.source-list li{margin-bottom:13px;font-size:12px;line-height:1.75;color:var(--muted)}.source-list a{overflow-wrap:anywhere}.methods-full{max-width:860px;padding-bottom:60px}.methods-full .prose h2{padding-top:15px}.tools-footer{background:#102132;color:#d7e8f6;padding:36px 0;margin-top:0}.footer-row{display:flex;align-items:center;gap:30px;justify-content:space-between}.tools-footer p{font-size:12px;color:#aec5d7}.tools-footer a{color:#d7e8f6}.footer-links{display:flex;gap:23px;font-size:12px;flex-wrap:wrap}.noscript-note{padding:18px;background:var(--soft);border:1px solid var(--line);font-size:13px;margin-bottom:20px}
@media(max-width:1000px){.wrap{width:calc(100% - 48px)}.header-inner{gap:14px;padding-inline:17px}#primary-nav{gap:17px}.brand-name{font-size:20px}.brand-logo-wrap{width:58px;height:44px}.method-layout{gap:32px;grid-template-columns:1fr 240px}.calc-panel{padding:24px}.result-value{font-size:36px}.calculator-grid{gap:19px}}
@media(max-width:850px){.js .menu-toggle{display:flex}.js #primary-nav{display:none;position:absolute;top:calc(100% + 8px);left:0;right:0;background:var(--panel);border:1px solid var(--line);padding:14px 22px;border-radius:14px}.js .menu-open #primary-nav{display:flex;flex-direction:column;align-items:stretch;gap:4px}.site-header{top:8px;margin-top:8px}.calculator-grid{grid-template-columns:1fr}.result-panel{position:static}.method-layout{grid-template-columns:1fr;gap:10px}.aside-links{border-left:0;border-top:1px solid var(--line);padding:24px 0;margin-top:20px}.method-callout{display:block}.method-callout a{display:inline-block;margin-top:18px}.tool-card{padding:23px}.tool-card h2{font-size:24px}.tool-hero{padding-bottom:26px}.calc-panel{padding:25px}.result-value{font-size:43px}.header-actions{gap:8px}.header-inner{min-height:68px}}
@media(max-width:600px){.wrap{width:calc(100% - 36px)}.site-header{width:calc(100% - 20px);border-radius:13px}.header-inner{padding:7px 10px;gap:8px;min-height:65px}.brand{gap:7px}.brand-name{font-size:17px;letter-spacing:-.035em}.brand-lab{display:block;font-size:12px;letter-spacing:.08em;text-transform:uppercase;margin-top:4px}.brand-logo-wrap{width:48px;height:40px;padding:3px}.theme-label,.menu-label{display:none}.theme-toggle,.menu-toggle{width:42px;height:42px;padding:10px;min-height:42px}.header-actions{gap:5px}.breadcrumb{margin-block:26px 21px;font-size:10px;gap:7px}.tool-lead{font-size:15px}.hero-meta{font-size:10px;gap:10px 18px}.tool-hero .eyebrow{font-size:9px}.tool-index{grid-template-columns:1fr;gap:17px}.tool-card{min-height:245px;padding:25px}.tool-equation{font-size:23px}.method-callout{padding:23px 0}.method-callout h2{font-size:25px}.calc-panel{padding:21px;border-radius:15px}.fields{gap:17px 13px}.field label{font-size:12px}.field small{font-size:10.5px}.field input{font-size:15px}.field select{font-size:12px}.panel-title{margin-bottom:21px}.result-value{font-size:40px}.calculator-grid{margin-bottom:35px}.prose h2{font-size:25px}.prose p{font-size:13px}.formula{font-size:13px;padding:15px}.footer-row{display:block}.footer-links{margin-top:21px;gap:18px}.notice{font-size:11px}.prose td,.prose th{padding:10px;font-size:11px}.result-table{font-size:11px}.field.wide{grid-column:1/-1}}
@media(max-width:370px){.fields{grid-template-columns:1fr}.brand-name{font-size:16px}.brand-logo-wrap{width:40px;height:35px}.header-inner{padding-inline:8px}.theme-toggle,.menu-toggle{width:40px}.tool-equation{font-size:21px}.result-value{font-size:35px}.calc-panel{padding:18px}}
html:not(.js) #primary-nav{flex-wrap:wrap}html:not(.js) .header-inner{flex-wrap:wrap}html:not(.js) #primary-nav{flex-basis:100%}.form-controls{display:none}.js .form-controls{display:block}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*,*:before,*:after{animation:none!important;transition:none!important}}
@media print{.site-header,.export-actions,.calc-actions,.examples,.aside-links,.tools-footer{display:none!important}html[data-theme] body,html[data-theme] .calc-panel{background:white;color:#182f43}.wrap{width:100%}.calculator-grid{display:block}.calc-panel{break-inside:avoid;margin-bottom:20px}.result-panel{position:static}.method-layout{display:block}.tool-hero{padding-top:0}.prose p{color:#243b4d}.readout{color:#182f43}}
.js .export-actions.form-controls{display:flex}

/* Long reference names should remain readable on a phone. */
@media(max-width:600px){.fields{grid-template-columns:minmax(0,1fr)}.panel-title>.eyebrow{font-size:9px;letter-spacing:.06em}}
/* A dark on-screen theme must never produce low-contrast paper output. */
@media print{html[data-theme]{--paper:#fff;--ink:#182f43;--muted:#43586b;--line:#b6c6d3;--accent:#245cba;--panel:#fff;--soft:#edf2f7;--control-bg:#fff;color-scheme:light}input,select,textarea{color:#182f43;background:white}.calc-panel{box-shadow:none}.result-value{color:#245cba}.result-table th,.result-unit,.result-label{color:#43586b}}