/* Peak & Mass: material, signal, interpretation. Existing brand and data colors retained. */
:root{--editorial-gap:clamp(28px,4vw,64px);--motion-fast:180ms;--motion-open:780ms;--ease-out:cubic-bezier(.16,1,.3,1)}
html{scroll-behavior:auto;scrollbar-color:var(--muted) var(--paper)}
input{caret-color:var(--copper)}
.wrap{width:min(1280px,calc(100% - 96px))}
.site-header{border-bottom-color:var(--ink)}
.masthead{min-height:100px;gap:24px}
.nav-main{gap:22px}
.nav-main a{padding-block:14px;position:relative}
.nav-main a::after{content:"";position:absolute;height:1px;background:var(--copper);bottom:8px;left:0;right:0;transform:scaleX(0);transform-origin:left;transition:transform var(--motion-fast) var(--ease-out)}
.nav-main a:hover::after,.nav-main a:focus-visible::after{transform:scaleX(1)}
.languages a{min-width:36px;min-height:40px}
.hero{padding-top:40px}
.hero-intro{grid-template-columns:minmax(0,.88fr) minmax(0,1.12fr);gap:var(--editorial-gap);align-items:center;margin-bottom:48px}
.hero-copy{padding-block:16px}
.hero h1{font-size:clamp(3.8rem,6.4vw,5.8rem);line-height:.98;max-width:9ch;letter-spacing:-.025em;text-wrap:balance}
.hero-line{margin-top:28px}
.hero-line p{max-width:43ch;font-size:1.05rem;line-height:1.65}
.hero-image{max-width:none;margin:0}
.hero-image picture{overflow:hidden;background:#dedbd3}
.hero-image img{aspect-ratio:4/3;object-fit:cover;object-position:60% 50%}
.hero-image figcaption{font-size:.76rem;padding-top:10px;margin:0;max-width:none;border-bottom:1px solid var(--line);padding-bottom:10px}
.button,button.primary,.newsletter-submit{transition:background-color var(--motion-fast),border-color var(--motion-fast)}
.button svg,.guide-row>svg{transition:transform var(--motion-fast) var(--ease-out)}
.button:hover svg,.guide-row:hover>svg{transform:translateX(4px)}
.hero-plate{display:grid;grid-template-columns:260px minmax(0,1fr);column-gap:var(--editorial-gap);padding-block:28px 24px;border-top:1px solid var(--ink);border-bottom:1px solid var(--ink)}
.hero-plate .plate-heading{display:flex;flex-direction:column;align-items:flex-start;gap:0;padding-top:8px}
.hero-plate .plate-heading h2{font:400 2.15rem/1.1 var(--display);max-width:16ch;margin:0}
.hero-plate .plate-explain{margin:20px 0 24px;font-size:.87rem;line-height:1.6}
.hero-plate .segmented{display:flex;flex-direction:column;width:100%;padding:0;border:0;gap:6px}
.hero-plate .segmented button{text-align:left;border:1px solid var(--line);min-height:44px;padding-inline:14px}
.hero-plate .segmented button[aria-pressed=true]{border-color:var(--ink)}
.hero-plate .chart{margin:0;height:auto;max-height:none}
.hero-plate .chart text{font-size:15px}
.hero-plate .legend{gap:8px 18px;font-size:.76rem}
.hero-plate .plot-footer{align-items:flex-start;gap:16px}
.hero-plate .result-inline{white-space:normal;text-align:right;min-width:125px;font-size:.78rem}
.hero-plate .result-inline strong{display:block;font-size:1.6rem;line-height:1.2;margin:4px 0 0}
.hero-plate figcaption{margin-top:10px}
.section{padding-block:64px}
.section-head{grid-template-columns:1fr 1fr;gap:var(--editorial-gap);margin-bottom:38px}
.section-head h2{max-width:19ch;font-size:clamp(2.5rem,3.5vw,3.35rem)}
.section-head p{font-size:.95rem;max-width:40ch}
.method-feature{display:grid;grid-template-columns:.8fr 1.2fr;gap:var(--editorial-gap);align-items:start}
.method-feature>.editorial-image{margin:0;position:sticky;top:28px}
.method-feature>.editorial-image img{aspect-ratio:3/2;object-fit:contain;object-position:center}
.method-feature .guide-row{grid-template-columns:1fr 22px;gap:12px;padding:24px 0}
.method-feature .guide-row p{grid-column:1;grid-row:2;max-width:54ch}
.method-feature .guide-row>svg{grid-column:2;grid-row:1}
.method-feature .guide-row h3{font-size:1.9rem}
.method-feature .guide-row small{margin-top:7px}
.guide-row{transition:background-color var(--motion-fast),color var(--motion-fast)}
.guide-row:hover{background:rgba(20,46,62,.025)}
.teaching-section .resource-grid{gap:48px;grid-template-columns:1.2fr 1fr}
.resource-grid article+article{padding-left:48px}
.resource-grid article{padding-top:8px}
.resource-meta{font-variant-numeric:tabular-nums;border-top:1px solid var(--line);padding-top:16px;margin-top:24px}
.next-step{background:transparent;color:var(--ink);border-top:2px solid var(--ink);border-bottom:1px solid var(--line);padding:36px 0;margin:56px 0}
.next-step h2{max-width:24ch;font-size:clamp(2.2rem,3.3vw,3rem)}
.next-step .button{background:var(--ink);color:var(--white);border-color:var(--ink)}
.next-step .button:hover{background:var(--blue);color:var(--white)}
.next-step a:not(.button){color:var(--blue)}
.next-step .disclosure{color:var(--muted);max-width:100ch}
.newsletter:not(.newsletter-material){padding:40px;margin-block:48px 64px;background:var(--wash);border:0;gap:56px}
.newsletter h2{font-size:2.5rem}
.newsletter-copy p{font-size:.9rem}
.site-footer{background:var(--ink);color:var(--paper);padding:40px 0}
.site-footer a,.site-footer p{color:var(--paper)}
.site-footer a:hover{color:#c8ded9}
.site-footer .brand-symbol{background:var(--paper);padding:5px}
.site-footer .brand-wordmark,.site-footer .brand-wordmark .brand-amp{color:var(--paper)}
.reading{padding-top:28px}
.breadcrumbs{margin-bottom:28px}
.article-head{max-width:none;display:grid;grid-template-columns:minmax(0,1.4fr) minmax(0,1fr);column-gap:64px;border-bottom:1px solid var(--ink);padding-bottom:30px;align-items:start}
.article-head h1{grid-row:1/3;font-size:clamp(2.8rem,4.6vw,4.3rem);line-height:1.04;max-width:21ch;text-wrap:balance}
.article-head .summary{font-size:1.04rem;line-height:1.65;margin:6px 0 0;max-width:47ch}
.article-head .meta{font-size:.75rem;margin:20px 0 0;max-width:56ch;align-self:end}
.reading-grid{grid-template-columns:minmax(0,1fr) 220px;gap:84px;margin-top:36px}
.article-body{max-width:72ch}
.article-body>section{margin:48px 0}
.article-body h2{font-size:2.3rem;max-width:31ch;line-height:1.16}
.direct-answer{font-size:1.15rem;line-height:1.7;border:0;padding:0 0 28px}
.article-body .editorial-image{margin:32px 0}
.article-body .editorial-image img{max-height:480px;object-fit:cover}
.toc{border-top:1px solid var(--ink);padding-top:18px;top:24px}
.toc a{padding:9px 0;margin:0;border-bottom:1px solid var(--line);line-height:1.45;text-decoration:none}
.toc a[aria-current=location]{color:var(--copper);text-decoration:underline;text-underline-offset:.2em}
.toc strong{display:block;margin-bottom:12px}
.section-sources{padding-top:12px;border-top:1px solid var(--line)}
.downloads{list-style:none;padding:0;border-top:1px solid var(--line)}
.downloads li{margin:0;border-bottom:1px solid var(--line)}
.downloads a{display:block;padding:13px 0;text-decoration:none}
.downloads a:hover{text-decoration:underline}
.article-body .next-step{padding:30px 0}
.tool-page{padding-top:34px}
.tool-page>h1{font-size:clamp(2.8rem,4.3vw,4rem);max-width:25ch;line-height:1.08}
.tool-intro{max-width:65ch;font-size:1rem}
.tool-shell{margin-top:32px;padding-top:28px}
.tool-shell>h2{font-size:2rem}
.tool-layout{grid-template-columns:280px minmax(0,1fr);gap:40px}
.controls{padding:24px;background:var(--wash);gap:22px}
.controls .field{font-size:.85rem}
.controls .secondary{width:100%}
.controls .segmented{border:0;padding:0}
.controls .segmented button{text-align:left;border:1px solid var(--line);min-height:44px}
.tool-plot .chart{margin-top:0}
.tool-plot .result-inline{padding:10px 16px;background:var(--wash)}
.result-inline strong{font-variant-numeric:tabular-nums}
.simple>h1{max-width:23ch;font-size:clamp(2.8rem,4.6vw,4.3rem);line-height:1.07}
@media(max-width:1100px){.wrap{width:calc(100% - 56px)}.masthead{flex-wrap:wrap;gap:16px;min-height:116px;padding-block:16px}.nav-main{order:3;flex-basis:100%;margin:0;justify-content:space-between}.languages{margin-left:auto}.hero-intro{gap:32px}.hero h1{font-size:clamp(3.5rem,7vw,5rem)}.hero-line .actions{gap:16px}.hero-plate{grid-template-columns:230px minmax(0,1fr);gap:32px}.hero-plate .plot-footer{display:block}.hero-plate .result-inline{text-align:left;margin-top:12px}.hero-plate .result-inline strong{display:inline;margin-left:8px}.reading-grid{gap:44px;grid-template-columns:minmax(0,1fr) 210px}.article-head{gap:36px}.method-feature{grid-template-columns:.75fr 1.25fr;gap:32px}}
@media(max-width:950px){.hero-intro{display:grid}.hero-image{margin:0}.hero h1{font-size:3.8rem}.hero-line p{font-size:.98rem}.hero-line .actions{display:grid;justify-items:start}.hero-plate{grid-template-columns:210px minmax(0,1fr);gap:24px}.hero-plate .plate-heading h2{font-size:1.85rem}.hero-plate .chart-desktop{display:block}.hero-plate .chart-mobile{display:none}.reading-grid{display:flex;flex-direction:column}.toc{position:static;order:-1;display:grid;grid-template-columns:1fr 1fr;gap:0 24px;padding-bottom:16px}.toc strong{grid-column:1/-1}.article-head{grid-template-columns:1fr}.article-head h1{grid-row:auto;max-width:25ch}.article-head .summary{max-width:68ch;margin-top:22px}.article-head .meta{max-width:none}.article-body{max-width:100%}.tool-layout{display:flex;flex-direction:column}.controls{display:grid;grid-template-columns:1fr 1fr}.controls .segmented{width:100%;grid-column:1/-1}.controls .secondary{width:auto}.method-feature{display:block}.method-feature>.editorial-image{position:static;float:left;width:34%;margin:22px 28px 12px 0}.method-feature .guide-row{display:grid}.method-feature::after{content:"";display:block;clear:both}.method-feature .guide-list{display:flow-root}.newsletter:not(.newsletter-material){padding:28px;gap:32px}}
@media(max-width:680px){.wrap{width:calc(100% - 36px)}.masthead{gap:12px;padding-block:16px;min-height:0}.nav-main{column-gap:18px;row-gap:2px;justify-content:flex-start;flex-wrap:wrap}.nav-main a{min-height:40px;padding-block:8px;font-size:.78rem}.languages{padding-left:8px;gap:0}.languages a{min-width:30px;min-height:40px}.hero{padding-top:28px}.hero-intro{display:flex;flex-direction:column;gap:28px;margin-bottom:28px}.hero-copy{padding:0;width:100%}.hero h1{font-size:3.5rem;max-width:12ch}.hero-line{margin-top:22px}.hero-line p{font-size:1rem;max-width:none}.hero-line .actions{display:flex;gap:16px}.hero-image{width:100%;max-width:none}.hero-image img{aspect-ratio:3/2;object-position:60% center}.hero-image figcaption{font-size:.74rem}.hero-plate{display:block;padding-block:26px}.hero-plate .plate-heading{padding:0}.hero-plate .plate-heading h2{font-size:2.1rem;max-width:23ch}.hero-plate .plate-explain{margin:14px 0 18px}.hero-plate .segmented{flex-direction:row;gap:8px}.hero-plate .segmented button{flex:1;text-align:center}.hero-plate .chart-desktop{display:none}.hero-plate .chart-mobile{display:block;height:auto;max-height:none;margin-top:24px}.hero-plate .legend{font-size:.72rem;gap:8px 12px}.section{padding-block:44px}.section-head{margin-bottom:26px}.section-head h2{font-size:2.5rem;max-width:22ch}.method-feature>.editorial-image{float:none;width:100%;margin:0 0 24px}.method-feature>.editorial-image img{aspect-ratio:3/2;object-position:center}.method-feature .guide-row{padding-block:22px}.method-feature .guide-row h3{font-size:1.9rem}.teaching-section .resource-grid{display:block}.resource-grid article+article{padding:28px 0 0}.newsletter:not(.newsletter-material){padding:26px 20px;margin-block:36px 44px}.newsletter h2{font-size:2.25rem}.next-step{margin-block:40px;padding-block:28px}.next-step h2{font-size:2.4rem}.article-head h1{font-size:2.7rem;max-width:none}.article-head{padding-bottom:24px}.article-head .summary{font-size:1rem}.reading-grid{margin-top:24px;gap:24px}.toc{display:block}.toc a{padding-block:10px}.article-body h2{font-size:2rem}.article-body>section{margin-block:36px}.direct-answer{font-size:1.05rem}.controls{display:flex;padding:20px}.controls .segmented{flex-wrap:wrap}.tool-page>h1{font-size:2.7rem}.tool-shell>h2{font-size:1.95rem}.tool-plot .result-inline{display:inline-block}.simple>h1{font-size:2.7rem}}
@media(prefers-reduced-motion:reduce){*,*::before,*::after{animation:none!important;transition:none!important;scroll-behavior:auto!important}.button:hover svg,.guide-row:hover>svg{transform:none}}
@media print{.site-footer,.toc{display:none}.article-head{display:block}.hero-intro{display:block}.hero-image,.method-feature>.editorial-image{display:none}.hero-plate{display:block}.next-step{display:none}.reading-grid{display:block}.article-head h1{font-size:28pt}.wrap{width:100%}.controls{background:white}.newsletter{display:none}}
/* Keep the narrow reading path compact after the contents rail becomes in-flow. */
@media(max-width:950px){.article-head{row-gap:0}.toc{align-self:stretch;width:100%;margin-bottom:0}.reading-grid{gap:28px}.article-body>section:first-child{margin-top:0}}
.article-body .next-step .disclosure{color:var(--muted)}
/* A numerical result and its unit form one reading group in every locale. */
.response-result strong{white-space:nowrap;flex-shrink:0}
.response-result span{min-width:0}