/* Theory Intelligence: design system
   Black on white. Dark mode is a straight inversion.
   Type: Inter Tight for display, Inter for text, IBM Plex Mono for labels. */

:root {
  --bg: #ffffff;
  --fg: #0a0a0a;
  --fg-2: #4a4a4a;
  --fg-3: #8a8a8a;
  --rule: #0a0a0a;
  --rule-soft: #d6d6d6;
  --panel: #f3f3f3;
  --img-filter: grayscale(1) contrast(1.05);
  --max: 1320px;
  --gutter: clamp(20px, 4vw, 56px);
  --mono: "IBM Plex Mono", ui-monospace, SFMono-Regular, Menlo, monospace;
  --sans: "Inter", -apple-system, BlinkMacSystemFont, "Helvetica Neue", Arial, sans-serif;
  --display: "Inter Tight", "Inter", -apple-system, "Helvetica Neue", Arial, sans-serif;
  --ease: cubic-bezier(.2,.7,.2,1);
}
html[data-theme="dark"] {
  --bg: #0a0a0a;
  --fg: #ffffff;
  --fg-2: #bdbdbd;
  --fg-3: #7a7a7a;
  --rule: #ffffff;
  --rule-soft: #2c2c2c;
  --panel: #141414;
  --img-filter: grayscale(1) contrast(1.05) brightness(.92);
}
/* Light is the default. Dark mode is opt-in via the header toggle (persisted in localStorage). */

*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
body {
  margin: 0; background: var(--bg); color: var(--fg);
  font-family: var(--sans); font-size: 16px; line-height: 1.55;
  -webkit-font-smoothing: antialiased; text-rendering: optimizeLegibility;
  transition: background-color .25s var(--ease), color .25s var(--ease);
}
img { display: block; max-width: 100%; height: auto; filter: var(--img-filter); }
a { color: inherit; text-decoration: none; }
a:hover { text-decoration: underline; text-underline-offset: 3px; }
::selection { background: var(--fg); color: var(--bg); }
.skip { position: absolute; left: -999px; top: 8px; background: var(--fg); color: var(--bg); padding: 8px 12px; z-index: 100; }
.skip:focus { left: 8px; }

.wrap { max-width: var(--max); margin: 0 auto; padding: 0 var(--gutter); }
.mono { font-family: var(--mono); font-size: 11px; letter-spacing: .08em; text-transform: uppercase; line-height: 1.5; }
.rule { border: 0; border-top: 1px solid var(--rule); margin: 0; }
.rule-soft { border: 0; border-top: 1px solid var(--rule-soft); margin: 0; }

/* Header */
.site-header { position: sticky; top: 0; z-index: 50; background: var(--bg); border-bottom: 1px solid var(--rule); }
.site-header .bar { display: grid; grid-template-columns: 1fr auto 1fr; align-items: center; height: 64px; gap: 24px; }
.brand { font-family: var(--display); font-weight: 600; font-size: 18px; letter-spacing: -.01em; display: inline-flex; align-items: baseline; gap: 8px; }
.brand:hover { text-decoration: none; }
.brand .mono { color: var(--fg-3); }
.nav { display: flex; gap: 28px; justify-content: center; }
.nav a { font-size: 13.5px; color: var(--fg-2); }
.nav a[aria-current="page"], .nav a:hover { color: var(--fg); text-decoration: none; }
.header-right { display: flex; justify-content: flex-end; align-items: center; gap: 18px; }
.btn { display: inline-flex; align-items: center; gap: 10px; font-family: var(--mono); font-size: 11px; letter-spacing: .08em; text-transform: uppercase; border: 1px solid var(--rule); padding: 10px 16px; transition: background .2s var(--ease), color .2s var(--ease); }
.btn:hover { background: var(--fg); color: var(--bg); text-decoration: none; }
.btn.solid { background: var(--fg); color: var(--bg); }
.btn.solid:hover { background: transparent; color: var(--fg); }
.theme-toggle { width: 34px; height: 34px; border: 1px solid var(--rule); background: transparent; color: var(--fg); cursor: pointer; display: inline-grid; place-items: center; padding: 0; }
.theme-toggle:hover { background: var(--fg); color: var(--bg); }
.theme-toggle svg { width: 14px; height: 14px; }
.menu-btn { display: none; border: 1px solid var(--rule); background: none; color: var(--fg); width: 34px; height: 34px; cursor: pointer; padding: 0; }
.menu-btn span { display: block; width: 14px; height: 1px; background: currentColor; margin: 3px auto; }

/* Hero (home) */
.hero { padding: clamp(48px, 8vw, 110px) 0 clamp(40px, 6vw, 80px); text-align: center; }
.hero .meta-row { display: flex; justify-content: space-between; gap: 16px; color: var(--fg-3); margin-bottom: clamp(36px, 5vw, 72px); text-align: left; }
.hero .meta-row div { max-width: 240px; }
.display { font-family: var(--display); font-weight: 600; letter-spacing: -.035em; line-height: .92; text-transform: uppercase; margin: 0; }
.display.xl { font-size: clamp(40px, 8.6vw, 124px); }
.display.lg { font-size: clamp(34px, 6.2vw, 84px); }
.display.md { font-size: clamp(28px, 4.2vw, 56px); }
.display.sm { font-size: clamp(22px, 2.8vw, 36px); letter-spacing: -.02em; }
.hero-grid { display: grid; grid-template-columns: 1fr minmax(260px, 420px) 1fr; gap: clamp(24px, 4vw, 64px); align-items: center; margin: clamp(28px, 4vw, 56px) 0; }
.hero-grid figure { margin: 0; }
.hero-grid img { width: 100%; aspect-ratio: 4/5; object-fit: cover; }
.side-note { text-align: left; font-size: 13px; line-height: 1.6; color: var(--fg-2); padding-top: 14px; border-top: 1px solid var(--rule); position: relative; }
.side-note::after { content: ""; display: block; width: 32px; border-top: 1px solid var(--rule); margin-top: 18px; }
.side-note.right { text-align: right; }
.side-note.right::after { margin-left: auto; }
.hero-cta { display: flex; gap: 14px; justify-content: center; margin-top: clamp(28px, 4vw, 48px); }

/* Sections */
.section { padding: clamp(56px, 8vw, 120px) 0; }
.section.tight { padding: clamp(36px, 5vw, 72px) 0; }
.section-head { display: grid; grid-template-columns: 120px 1fr; gap: 24px; align-items: end; padding-bottom: 20px; border-bottom: 1px solid var(--rule); margin-bottom: clamp(32px, 4vw, 56px); }
.section-head .idx { font-family: var(--mono); font-size: 11px; letter-spacing: .08em; color: var(--fg-3); }
.section-head h2 { margin: 0; }
.section-head .right { grid-column: 1 / -1; color: var(--fg-2); max-width: 640px; font-size: 15px; }
@media (min-width: 900px) { .section-head { grid-template-columns: 120px 1fr 360px; } .section-head .right { grid-column: auto; text-align: right; justify-self: end; } }

.lead { font-size: clamp(18px, 1.6vw, 22px); line-height: 1.45; letter-spacing: -.01em; max-width: 880px; }
.lead.center { margin: 0 auto; text-align: center; }
.statement { font-family: var(--display); font-weight: 500; letter-spacing: -.025em; font-size: clamp(24px, 3.4vw, 46px); line-height: 1.12; max-width: 1100px; }
.statement.indent span { display: block; }
.statement.indent span:nth-child(2) { padding-left: 8%; }
.statement.indent span:nth-child(3) { padding-left: 16%; }
.statement.indent span:nth-child(4) { padding-left: 24%; }

.grid-2 { display: grid; grid-template-columns: 1fr; gap: clamp(28px, 4vw, 64px); }
.grid-3 { display: grid; grid-template-columns: 1fr; gap: clamp(24px, 3vw, 40px); }
.grid-4 { display: grid; grid-template-columns: 1fr 1fr; gap: clamp(20px, 3vw, 32px); }
@media (min-width: 760px) { .grid-2 { grid-template-columns: 1fr 1fr; } .grid-3 { grid-template-columns: repeat(3, 1fr); } .grid-4 { grid-template-columns: repeat(4, 1fr); } }
.grid-2.asym { grid-template-columns: 1fr; }
@media (min-width: 900px) { .grid-2.asym { grid-template-columns: 5fr 7fr; } .grid-2.asym.rev { grid-template-columns: 7fr 5fr; } }

.cell { border-top: 1px solid var(--rule); padding-top: 18px; }
.cell .mono { color: var(--fg-3); display: block; margin-bottom: 14px; }
.cell h3 { font-family: var(--display); font-weight: 600; letter-spacing: -.02em; font-size: 22px; margin: 0 0 10px; line-height: 1.15; }
.cell p { margin: 0; color: var(--fg-2); font-size: 15px; }
.cell .num { font-family: var(--display); font-weight: 600; font-size: clamp(40px, 5vw, 64px); letter-spacing: -.04em; line-height: 1; margin: 0 0 10px; }

/* Index list (services, articles) */
.index { border-top: 1px solid var(--rule); }
.index-row { display: grid; grid-template-columns: 48px 1fr 28px; gap: 16px; align-items: start; padding: 22px 0; border-bottom: 1px solid var(--rule); color: inherit; }
.index-row:hover { text-decoration: none; }
.index-row:hover .title { text-decoration: underline; text-underline-offset: 4px; }
.index-row .n { font-family: var(--mono); font-size: 11px; color: var(--fg-3); padding-top: 8px; }
.index-row .title { font-family: var(--display); font-weight: 600; font-size: clamp(20px, 2.4vw, 30px); letter-spacing: -.02em; line-height: 1.1; margin: 0; }
.index-row .sub { color: var(--fg-2); font-size: 14px; margin: 8px 0 0; max-width: 640px; }
.index-row .meta { font-family: var(--mono); font-size: 11px; letter-spacing: .08em; text-transform: uppercase; color: var(--fg-3); text-align: right; line-height: 1.6; padding-top: 8px; }
.index-row .arrow { font-family: var(--display); font-size: 22px; line-height: 1; text-align: right; padding-top: 4px; transition: transform .25s var(--ease); }
.index-row:hover .arrow { transform: translateX(6px); }
@media (min-width: 900px) { .index-row { grid-template-columns: 80px 1fr 300px 48px; gap: 24px; } }

/* Image panels */
.panel { position: relative; overflow: hidden; background: var(--panel); }
.panel img { width: 100%; height: 100%; object-fit: cover; }
.panel.wide img { aspect-ratio: 21/9; }
.panel.tall img { aspect-ratio: 4/5; }
.panel.square img { aspect-ratio: 1/1; }
.panel.landscape img { aspect-ratio: 3/2; }
.panel .cap { position: absolute; left: 16px; bottom: 14px; color: #fff; mix-blend-mode: difference; }
.triptych { display: grid; grid-template-columns: repeat(3, 1fr); gap: 12px; }
.triptych img { aspect-ratio: 3/4; object-fit: cover; width: 100%; }
figcaption { font-family: var(--mono); font-size: 11px; letter-spacing: .08em; text-transform: uppercase; color: var(--fg-3); margin-top: 10px; }

/* Band: inverted block */
.band { background: var(--fg); color: var(--bg); }
.band .mono, .band .cell p, .band .cell .mono { color: inherit; opacity: .7; }
.band .cell { border-top-color: var(--bg); }
.band .btn { border-color: var(--bg); }
.band .btn:hover { background: var(--bg); color: var(--fg); }
.band ::selection { background: var(--bg); color: var(--fg); }

/* Page header (interior) */
.page-head { padding: clamp(40px, 6vw, 88px) 0 clamp(28px, 4vw, 48px); border-bottom: 1px solid var(--rule); }
.crumbs { display: flex; gap: 10px; color: var(--fg-3); margin-bottom: 28px; flex-wrap: wrap; }
.crumbs a:hover { color: var(--fg); }
.page-head h1 { margin: 0 0 20px; }
.page-head .lead { color: var(--fg-2); }

/* Prose */
.prose { max-width: 720px; font-size: 17px; line-height: 1.65; }
.prose p { margin: 0 0 1.35em; }
.prose h2 { font-family: var(--display); font-weight: 600; letter-spacing: -.025em; font-size: clamp(26px, 3vw, 36px); line-height: 1.1; margin: 2.2em 0 .7em; }
.prose h3 { font-family: var(--display); font-weight: 600; letter-spacing: -.02em; font-size: 22px; margin: 1.8em 0 .6em; }
.prose ul, .prose ol { padding-left: 1.2em; margin: 0 0 1.4em; }
.prose li { margin-bottom: .45em; }
.prose blockquote { margin: 1.6em 0; padding: 0 0 0 20px; border-left: 1px solid var(--rule); font-family: var(--display); font-size: 22px; letter-spacing: -.015em; line-height: 1.3; }
.prose blockquote cite { display: block; font-family: var(--mono); font-size: 11px; letter-spacing: .08em; text-transform: uppercase; color: var(--fg-3); margin-top: 10px; font-style: normal; }
.prose a { text-decoration: underline; text-underline-offset: 3px; text-decoration-color: var(--fg-3); }
.prose a:hover { text-decoration-color: var(--fg); }
.prose table { width: 100%; border-collapse: collapse; margin: 1.5em 0 2em; font-size: 14.5px; }
.prose th { font-family: var(--mono); font-size: 11px; letter-spacing: .08em; text-transform: uppercase; text-align: left; padding: 10px 12px 10px 0; border-bottom: 1px solid var(--rule); color: var(--fg-3); }
.prose td { padding: 12px 12px 12px 0; border-bottom: 1px solid var(--rule-soft); vertical-align: top; }
.prose .keyfacts { border: 1px solid var(--rule); padding: 22px 24px; margin: 0 0 2em; font-size: 15px; }
.prose .keyfacts .mono { color: var(--fg-3); display: block; margin-bottom: 10px; }
.prose .keyfacts ul { margin: 0; padding-left: 1.1em; }
.prose .keyfacts li { margin-bottom: .35em; }
.prose .definition { font-family: var(--display); font-size: clamp(20px, 2.2vw, 26px); letter-spacing: -.02em; line-height: 1.3; padding: 0 0 22px; border-bottom: 1px solid var(--rule); margin-bottom: 1.6em; }
.article-layout { display: grid; grid-template-columns: 1fr; gap: 48px; }
@media (min-width: 1000px) { .article-layout { grid-template-columns: 260px 1fr; } .article-layout aside { position: sticky; top: 88px; align-self: start; } }
.aside-block { border-top: 1px solid var(--rule); padding-top: 14px; margin-bottom: 28px; font-size: 14px; color: var(--fg-2); }
.aside-block .mono { display: block; color: var(--fg-3); margin-bottom: 8px; }
.aside-block a { display: block; padding: 4px 0; }
.byline { display: flex; gap: 24px; color: var(--fg-3); margin-top: 18px; flex-wrap: wrap; }

/* FAQ */
.faq { border-top: 1px solid var(--rule); }
.faq details { border-bottom: 1px solid var(--rule); }
.faq summary { cursor: pointer; list-style: none; padding: 22px 0; font-family: var(--display); font-weight: 500; font-size: 20px; letter-spacing: -.015em; display: flex; justify-content: space-between; gap: 20px; }
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after { content: "+"; font-family: var(--mono); font-weight: 400; }
.faq details[open] summary::after { content: "\2212"; }
.faq .a { padding: 0 0 24px; color: var(--fg-2); max-width: 760px; font-size: 16px; }

/* Pricing */
.price-card { border: 1px solid var(--rule); padding: 28px; display: flex; flex-direction: column; gap: 14px; min-height: 100%; }
.price-card .mono { color: var(--fg-3); }
.price-card h3 { font-family: var(--display); font-weight: 600; font-size: 28px; letter-spacing: -.025em; margin: 0; line-height: 1.05; }
.price-card .price { font-family: var(--display); font-weight: 600; font-size: 22px; letter-spacing: -.02em; }
.price-card p { margin: 0; color: var(--fg-2); font-size: 15px; }
.price-card ul { margin: 0; padding-left: 1.1em; color: var(--fg-2); font-size: 14.5px; }
.price-card .btn { align-self: flex-start; margin-top: auto; }

/* Steps */
.steps { counter-reset: step; }
.step { display: grid; grid-template-columns: 56px 1fr; gap: 20px; padding: 24px 0; border-top: 1px solid var(--rule); }
.step:last-child { border-bottom: 1px solid var(--rule); }
.step .n { font-family: var(--mono); font-size: 11px; color: var(--fg-3); padding-top: 6px; }
.step h3 { margin: 0 0 8px; font-family: var(--display); font-weight: 600; font-size: 22px; letter-spacing: -.02em; }
.step p { margin: 0; color: var(--fg-2); max-width: 720px; }
@media (min-width: 900px) { .step { grid-template-columns: 120px 320px 1fr; } .step p { grid-column: 3; } .step h3 { grid-column: 2; } .step .n { grid-column: 1; } }

/* Contact */
.contact-grid { display: grid; grid-template-columns: 1fr; gap: 40px; }
@media (min-width: 900px) { .contact-grid { grid-template-columns: 1fr 1fr; } }
.email-big { font-family: var(--display); font-weight: 600; font-size: clamp(24px, 4vw, 52px); letter-spacing: -.03em; line-height: 1; word-break: break-all; }
form.contact { display: grid; gap: 18px; }
form.contact label { display: grid; gap: 8px; font-family: var(--mono); font-size: 11px; letter-spacing: .08em; text-transform: uppercase; color: var(--fg-3); }
form.contact input, form.contact textarea, form.contact select { width: 100%; font: inherit; font-size: 16px; color: var(--fg); background: transparent; border: 0; border-bottom: 1px solid var(--rule); padding: 10px 0; border-radius: 0; }
form.contact textarea { min-height: 120px; resize: vertical; }
form.contact input:focus, form.contact textarea:focus, form.contact select:focus { outline: none; border-bottom-width: 2px; }

/* Footer */
.site-footer { border-top: 1px solid var(--rule); padding: clamp(40px, 6vw, 80px) 0 32px; }
.footer-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 32px; margin-bottom: clamp(40px, 6vw, 80px); }
@media (min-width: 900px) { .footer-grid { grid-template-columns: 2fr 1fr 1fr 1fr 1fr; } }
.footer-grid .mono { color: var(--fg-3); display: block; margin-bottom: 14px; }
.footer-grid a { display: block; font-size: 14px; padding: 3px 0; color: var(--fg-2); }
.footer-grid a:hover { color: var(--fg); }
.footer-grid p { color: var(--fg-2); font-size: 14px; max-width: 320px; margin: 0; }
.footer-word { font-family: var(--display); font-weight: 600; text-transform: uppercase; letter-spacing: -.05em; line-height: .8; font-size: clamp(64px, 17vw, 260px); margin: 0 0 24px; }
.footer-bottom { display: flex; justify-content: space-between; gap: 16px; flex-wrap: wrap; color: var(--fg-3); border-top: 1px solid var(--rule-soft); padding-top: 18px; }

/* Utilities */
.mt-0 { margin-top: 0; } .mb-0 { margin-bottom: 0; }
.center { text-align: center; }
.muted { color: var(--fg-2); }
.small { font-size: 14px; }
.stack > * + * { margin-top: 16px; }
.reveal { opacity: 0; transform: translateY(14px); transition: opacity .7s var(--ease), transform .7s var(--ease); }
.reveal.in { opacity: 1; transform: none; }
@media (prefers-reduced-motion: reduce) { .reveal { opacity: 1; transform: none; transition: none; } html { scroll-behavior: auto; } }

/* Mobile nav */
@media (max-width: 860px) {
  .site-header .bar { grid-template-columns: auto 1fr auto; }
  .nav { display: none; position: absolute; left: 0; right: 0; top: 64px; z-index: 60; background: var(--bg); border-bottom: 1px solid var(--rule); flex-direction: column; gap: 0; padding: 8px 0 16px; }
  .nav.open { display: flex; }
  .nav a { padding: 12px var(--gutter); font-size: 18px; font-family: var(--display); }
  .menu-btn { display: inline-block; }
  .header-right .btn { display: none; }
  .hero .meta-row { display: none; }
  .hero-grid { grid-template-columns: 1fr; }
  .hero-grid figure { order: -1; max-width: 320px; margin: 0 auto; }
  .side-note.right { text-align: left; } .side-note.right::after { margin-left: 0; }
  .index-row .meta { display: none; }
  .triptych { grid-template-columns: 1fr; }
  .triptych img { aspect-ratio: 16/10; }
}