/* ir.petrov.re — a plain table of very old wood. */
:root {
  --paper: #f2ede4;
  --paper-2: #e9e2d5;
  --paper-3: #ded5c5;
  --ink: #221d17;
  --ink-2: #5b5046;
  --ink-3: #8a7e72;
  --rule: rgba(34, 29, 23, .16);
  --rule-2: rgba(34, 29, 23, .32);
  --acc: #8a5a32;
  --acc-2: #6e4422;
  --serif: "Source Serif 4", "Source Serif Pro", Georgia, "Times New Roman", serif;
  --sans: "Inter", "Segoe UI", system-ui, sans-serif;
  --w: 1180px;
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root {
    --paper: #17130f;
    --paper-2: #1e1914;
    --paper-3: #2a231c;
    --ink: #ece4d6;
    --ink-2: #b9ad9c;
    --ink-3: #8c8072;
    --rule: rgba(236, 228, 214, .14);
    --rule-2: rgba(236, 228, 214, .3);
    --acc: #c99467;
    --acc-2: #e0b088;
    color-scheme: dark;
  }
  .plate img { filter: invert(.92) hue-rotate(180deg) saturate(.8); }
}

*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font: 400 1.1875rem/1.62 var(--serif);
  font-optical-sizing: auto;
  font-variant-numeric: oldstyle-nums proportional-nums;
  font-kerning: normal;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}
/* paper grain, barely there */
body::before {
  content: ""; position: fixed; inset: 0; pointer-events: none; z-index: 0; opacity: .5;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='220' height='220'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.9' numOctaves='2' stitchTiles='stitch'/%3E%3CfeColorMatrix values='0 0 0 0 0.13 0 0 0 0 0.11 0 0 0 0 0.09 0 0 0 .05 0'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
}
main, .top, .foot { position: relative; z-index: 1; }
::selection { background: var(--acc); color: var(--paper); }
a { color: inherit; text-decoration-thickness: 1px; text-underline-offset: .18em; text-decoration-color: var(--rule-2); transition: color .2s, text-decoration-color .2s; }
a:hover { color: var(--acc); text-decoration-color: var(--acc); }
:focus-visible { outline: 1px solid var(--acc); outline-offset: 3px; }
.wrap { max-width: var(--w); margin: 0 auto; padding: 0 clamp(20px, 4vw, 48px); }
.skip { position: absolute; left: -999px; }
.skip:focus { left: 12px; top: 12px; z-index: 9; background: var(--paper); padding: 6px 10px; }

.label, .kicker, .nav, .langs, .tab, .btn, .pick-n, .case-tags, .row-head, .facts-dl dt, figcaption, .form span, .status, .foot .small {
  font-family: var(--sans);
  font-feature-settings: "cv11", "ss01";
}
.label, .kicker {
  display: block; font-size: .72rem; font-weight: 500; letter-spacing: .16em; text-transform: uppercase; color: var(--ink-3);
}

/* header */
.top { border-bottom: 1px solid var(--rule); background: color-mix(in srgb, var(--paper) 88%, transparent); position: sticky; top: 0; backdrop-filter: blur(6px); z-index: 5; }
.top::after { content: ""; position: absolute; left: 0; right: 0; bottom: -4px; border-bottom: 1px solid var(--rule); }
.top-in { display: flex; align-items: center; gap: 28px; height: 64px; }
.mark { font-family: var(--serif); font-size: 1.15rem; text-decoration: none; letter-spacing: .01em; white-space: nowrap; }
.mark .ir { font-style: italic; color: var(--acc); }
.nav { display: flex; gap: 26px; margin-left: auto; font-size: .78rem; letter-spacing: .08em; text-transform: uppercase; }
.nav a, .langs a { text-decoration: none; color: var(--ink-2); }
.nav a:hover, .langs a:hover { color: var(--acc); }
.langs { display: flex; gap: 2px; font-size: .7rem; letter-spacing: .1em; }
.langs a { padding: 4px 6px; border: 1px solid transparent; }
.langs a[aria-current] { color: var(--ink); border-color: var(--rule-2); }

/* type */
h1, h2, h3, h4 { font-weight: 400; margin: 0; }
h1 { font-size: clamp(2.6rem, 6.2vw, 5rem); line-height: 1.02; letter-spacing: -.022em; font-variation-settings: "opsz" 60; }
.sec { font-size: clamp(2rem, 3.6vw, 3rem); letter-spacing: -.015em; line-height: 1.08; margin-bottom: .5em; font-variation-settings: "opsz" 60; }
.sec.small { font-size: clamp(1.6rem, 2.6vw, 2.2rem); margin-top: 2.2em; }
.sec::before { content: ""; display: block; width: 44px; height: 1px; background: var(--acc); margin-bottom: 22px; }
.lead { font-size: 1.32rem; line-height: 1.5; color: var(--ink-2); max-width: 36em; }
.intro { color: var(--ink-2); max-width: 40em; margin: 0 0 2.2em; }
p { margin: 0 0 1em; hyphens: auto; }
section { padding: clamp(64px, 9vw, 120px) 0 0; }

/* buttons */
.btn {
  display: inline-block; font-size: .76rem; letter-spacing: .14em; text-transform: uppercase; text-decoration: none; font-weight: 500;
  background: var(--ink); color: var(--paper); border: 1px solid var(--ink); padding: 15px 26px; cursor: pointer; transition: background .25s, color .25s, border-color .25s;
}
.btn:hover { background: var(--acc-2); border-color: var(--acc-2); color: var(--paper); }
.btn.ghost { background: transparent; color: var(--ink); border-color: var(--rule-2); }
.btn.ghost:hover { border-color: var(--acc); color: var(--acc); }
.ctas { display: flex; gap: 12px; flex-wrap: wrap; margin-top: 2em; }

/* plates */
.plate { margin: 0; }
.plate img { display: block; width: 100%; height: auto; }
figcaption { font-size: .72rem; letter-spacing: .04em; color: var(--ink-3); margin-top: 12px; border-top: 1px solid var(--rule); padding-top: 10px; font-style: normal; }

/* hero */
.hero { display: grid; grid-template-columns: 1.05fr 1fr; gap: clamp(32px, 5vw, 72px); align-items: end; padding-top: clamp(56px, 9vw, 120px); }
.hero .kicker { margin-bottom: 28px; }
.hero h1 { margin-bottom: 30px; }
.hero .plate { align-self: center; }

/* facts */
.facts ul { list-style: none; margin: 0; padding: 26px 0; display: grid; grid-template-columns: repeat(4, 1fr); border-top: 1px solid var(--rule); border-bottom: 1px solid var(--rule); }
.facts li { padding: 0 22px; border-left: 1px solid var(--rule); color: var(--ink-2); font-size: .95rem; line-height: 1.4; }
.facts li:first-child { border-left: 0; padding-left: 0; }
.facts .fig { display: block; font-size: 2.3rem; color: var(--ink); font-variant-numeric: lining-nums; letter-spacing: -.01em; margin-bottom: 4px; }
.facts { padding-top: clamp(48px, 6vw, 80px); }

/* approach */
.approach-grid { display: grid; grid-template-columns: 1.1fr 1fr; gap: clamp(32px, 5vw, 72px); align-items: start; }
.principles { list-style: none; margin: 0; padding: 0; }
.principles li { display: grid; grid-template-columns: 44px 1fr; column-gap: 8px; padding: 22px 0; border-top: 1px solid var(--rule); }
.principles li:last-child { border-bottom: 1px solid var(--rule); }
.principles .num { grid-row: span 2; font-style: italic; color: var(--acc); font-size: 1.4rem; line-height: 1.2; }
.principles h3 { font-size: 1.45rem; margin-bottom: 6px; }
.principles p { color: var(--ink-2); margin: 0; }

/* explorer */
.explore { margin-top: clamp(64px, 9vw, 120px); padding-bottom: clamp(56px, 8vw, 100px); background: var(--paper-2); border-top: 1px solid var(--rule); border-bottom: 1px solid var(--rule); }
.tabs { display: inline-flex; border: 1px solid var(--rule-2); margin-bottom: 36px; }
.tab { background: none; border: 0; padding: 12px 20px; font-size: .74rem; letter-spacing: .14em; text-transform: uppercase; color: var(--ink-2); cursor: pointer; }
.tab + .tab { border-left: 1px solid var(--rule-2); }
.tab.is-on { background: var(--ink); color: var(--paper); }
.explorer-panel { display: none; grid-template-columns: minmax(240px, 330px) 1fr; gap: clamp(28px, 4vw, 64px); align-items: start; }
.explorer-panel.is-on { display: grid; }
.picks { list-style: none; margin: 0; padding: 0; position: sticky; top: 92px; }
.pick {
  display: flex; gap: 14px; align-items: baseline; width: 100%; text-align: left; background: none; border: 0; border-top: 1px solid var(--rule);
  padding: 13px 4px; font: inherit; font-size: 1.04rem; line-height: 1.3; color: var(--ink-2); cursor: pointer; transition: color .2s, padding .25s;
}
.picks li:last-child .pick { border-bottom: 1px solid var(--rule); }
.pick:hover { color: var(--ink); padding-left: 10px; }
.pick.is-on { color: var(--ink); padding-left: 10px; box-shadow: inset 2px 0 0 var(--acc); }
.pick-n { font-size: .66rem; letter-spacing: .1em; color: var(--ink-3); min-width: 1.6em; }
.detail { display: none; animation: rise .45s ease both; }
.detail.is-on { display: block; }
@keyframes rise { from { opacity: 0; transform: translateY(6px); } to { opacity: 1; transform: none; } }
.detail h3 { font-size: clamp(1.7rem, 2.8vw, 2.4rem); letter-spacing: -.01em; line-height: 1.1; margin-bottom: 10px; }
.detail .blurb { color: var(--ink-2); max-width: 38em; margin-bottom: 26px; }
.rows { list-style: none; margin: 0; padding: 0; counter-reset: r; }
.row { padding: 20px 0 18px; border-top: 1px solid var(--rule); display: grid; grid-template-columns: 220px 1fr; column-gap: 28px; }
.row:last-child { border-bottom: 1px solid var(--rule); }
.row-head { font-size: .74rem; letter-spacing: .1em; text-transform: uppercase; color: var(--ink-3); font-weight: 500; padding-top: 6px; }
.row .q { margin: 0; font-style: italic; font-size: 1.14rem; line-height: 1.5; }
.row-cases { grid-column: 2; margin-top: 10px; display: flex; flex-wrap: wrap; gap: 6px 16px; align-items: baseline; }
.row-cases .label { color: var(--acc); }
.case-link { font-size: .98rem; color: var(--ink); text-decoration-color: var(--acc); }

/* cases */
.cases .plate { margin: 0 0 36px; }
.case-list { display: grid; grid-template-columns: repeat(2, 1fr); gap: 0 clamp(28px, 4vw, 56px); }
.case { border-top: 1px solid var(--rule); scroll-margin-top: 90px; }
.case summary { list-style: none; cursor: pointer; padding: 24px 0 22px; display: block; }
.case summary::-webkit-details-marker { display: none; }
.case-tags { display: block; font-size: .66rem; letter-spacing: .12em; text-transform: uppercase; color: var(--ink-3); line-height: 1.6; margin-bottom: 10px; }
.case-title { display: block; font-size: 1.42rem; line-height: 1.2; letter-spacing: -.005em; margin-bottom: 10px; transition: color .2s; }
.case summary:hover .case-title { color: var(--acc); }
.case-sym { display: block; color: var(--ink-2); font-size: 1.02rem; }
.case-more { display: inline-block; margin-top: 12px; font-family: var(--sans); font-size: .7rem; letter-spacing: .14em; text-transform: uppercase; color: var(--acc); }
.case-more::before { content: attr(data-more) " →"; }
.case[open] .case-more::before { content: attr(data-less) " ↑"; }
.case-body { padding: 0 0 28px; }
.case-body h4 { font-family: var(--sans); font-size: .7rem; letter-spacing: .14em; text-transform: uppercase; color: var(--ink-3); margin: 10px 0 6px; font-weight: 500; }
.case-body p { font-size: 1.04rem; }
.case-body .lesson { font-style: italic; border-left: 2px solid var(--acc); padding: 4px 0 4px 16px; margin-top: 18px; }
.case-body .lesson .label { font-style: normal; margin-bottom: 4px; color: var(--acc); }
.case.flash .case-title { color: var(--acc); }

/* nuclear */
.nuclear { margin-top: clamp(64px, 9vw, 120px); padding-bottom: clamp(64px, 9vw, 110px); background: var(--paper-2); border-top: 1px solid var(--rule); border-bottom: 1px solid var(--rule); }
.nuclear-grid { display: grid; grid-template-columns: 1.2fr .9fr; gap: clamp(32px, 5vw, 72px); align-items: center; }
.nuclear h3.label { margin: 32px 0 12px; }
.topics { margin: 0; padding: 0; list-style: none; }
.topics li { padding: 8px 0 8px 22px; border-top: 1px solid var(--rule); position: relative; }
.topics li::before { content: "—"; position: absolute; left: 0; color: var(--acc); }
.pubs { margin: 0; padding: 0; list-style: none; counter-reset: p; }
.pubs li { padding: 12px 0; border-top: 1px solid var(--rule); counter-increment: p; }
.pubs a { display: block; font-style: italic; line-height: 1.35; }
.pubs span { display: block; font-family: var(--sans); font-size: .76rem; color: var(--ink-3); margin-top: 4px; }
.note { font-size: .9rem; color: var(--ink-3); margin-top: 22px; }

/* about */
.about-grid { display: grid; grid-template-columns: 1.3fr 1fr; gap: clamp(32px, 5vw, 72px); }
.prose p { max-width: 36em; }
.prose p:last-child { font-style: italic; color: var(--ink-2); }
.facts-dl { margin: 0; }
.facts-dl div { padding: 12px 0; border-top: 1px solid var(--rule); }
.facts-dl div:last-child { border-bottom: 1px solid var(--rule); }
.facts-dl dt { font-size: .68rem; letter-spacing: .14em; text-transform: uppercase; color: var(--ink-3); margin-bottom: 3px; }
.facts-dl dd { margin: 0; font-size: 1.02rem; }
.work { list-style: none; margin: 0; padding: 0; display: grid; grid-template-columns: repeat(4, 1fr); gap: 0; border-top: 1px solid var(--rule); }
.work li { padding: 22px 22px 6px 0; }
.work li + li { padding-left: 22px; border-left: 1px solid var(--rule); }
.work h4 { font-size: 1.25rem; margin-bottom: 8px; }
.work p { color: var(--ink-2); font-size: 1rem; }

/* contact */
.contact { padding-bottom: clamp(64px, 9vw, 120px); }
.contact-grid { display: grid; grid-template-columns: .9fr 1.1fr; gap: clamp(32px, 6vw, 96px); align-items: start; }
.direct { margin-top: 28px; font-size: 1.15rem; line-height: 1.7; }
.direct .label { margin-bottom: 4px; }
.plate-globe { max-width: 260px; margin-top: 36px; }
.form { display: grid; grid-template-columns: 1fr 1fr; gap: 22px 28px; padding-top: 10px; }
.form label { display: block; }
.form .full { grid-column: 1 / -1; }
.form span { display: block; font-size: .68rem; letter-spacing: .14em; text-transform: uppercase; color: var(--ink-3); margin-bottom: 6px; }
.form em { font-style: normal; text-transform: none; letter-spacing: 0; color: var(--ink-3); opacity: .8; }
.form input, .form select, .form textarea {
  width: 100%; font: inherit; font-size: 1.08rem; color: var(--ink); background: transparent; border: 0; border-bottom: 1px solid var(--rule-2); padding: 8px 0; border-radius: 0; transition: border-color .2s;
}
.form select { appearance: none; background-image: linear-gradient(45deg, transparent 50%, var(--ink-3) 50%), linear-gradient(135deg, var(--ink-3) 50%, transparent 50%); background-position: calc(100% - 12px) 55%, calc(100% - 7px) 55%; background-size: 5px 5px; background-repeat: no-repeat; }
.form select option { background: var(--paper); }
.form textarea { resize: vertical; border: 1px solid var(--rule-2); padding: 12px 14px; min-height: 170px; line-height: 1.5; }
.form input:focus, .form select:focus, .form textarea:focus { outline: none; border-color: var(--acc); }
.form .consent { display: flex; gap: 12px; align-items: flex-start; }
.form .consent input { width: auto; margin-top: 4px; accent-color: var(--acc); }
.form .consent span { text-transform: none; letter-spacing: 0; font-size: .86rem; color: var(--ink-2); margin: 0; }
.send { display: flex; align-items: center; gap: 22px; flex-wrap: wrap; }
.status { margin: 0; font-size: .86rem; color: var(--ink-2); }
.status.ok { color: var(--acc); }
.status.err { color: #a33a2a; }
.hp { position: absolute; left: -9999px; width: 1px; height: 1px; overflow: hidden; }
.form.done > *:not(.send) { opacity: .35; pointer-events: none; }
.form.done .btn { display: none; }

/* footer */
.foot { border-top: 1px solid var(--rule); padding: 40px 0 56px; font-size: .95rem; color: var(--ink-2); }
.foot::before { content: ""; display: block; border-top: 1px solid var(--rule); margin-top: -44px; margin-bottom: 40px; }
.foot-in { display: grid; grid-template-columns: 1fr 1.6fr auto; gap: 40px; align-items: start; }
.foot .mark { font-size: 1.1rem; color: var(--ink); }
.foot .small { font-size: .78rem; line-height: 1.6; color: var(--ink-3); }

/* responsive */
@media (max-width: 1080px) {
  .nav { display: none; }
  .langs { margin-left: auto; }
  .work { grid-template-columns: 1fr 1fr; }
  .work li:nth-child(3) { border-left: 0; padding-left: 0; }
}
@media (max-width: 860px) {
  body { font-size: 1.09rem; }
  .hero, .approach-grid, .nuclear-grid, .about-grid, .contact-grid { grid-template-columns: 1fr; }
  .facts ul { grid-template-columns: 1fr 1fr; gap: 22px 0; }
  .facts li:nth-child(3) { border-left: 0; padding-left: 0; }
  .explorer-panel.is-on { grid-template-columns: 1fr; }
  .picks { position: static; display: flex; overflow-x: auto; gap: 0; scroll-snap-type: x mandatory; border-bottom: 1px solid var(--rule); margin: 0 -20px; padding: 0 20px; }
  .picks li { flex: 0 0 auto; scroll-snap-align: start; }
  .pick, .picks li:last-child .pick { border: 0; padding: 12px 14px 12px 0; white-space: nowrap; }
  .pick.is-on, .pick:hover { padding-left: 0; box-shadow: inset 0 -2px 0 var(--acc); }
  .row { grid-template-columns: 1fr; }
  .row-cases { grid-column: 1; }
  .case-list { grid-template-columns: 1fr; }
  .foot-in { grid-template-columns: 1fr; }
  .lead { font-size: 1.18rem; }
}
@media (max-width: 560px) {
  .form { grid-template-columns: 1fr; }
  .work { grid-template-columns: 1fr; }
  .work li + li { border-left: 0; padding-left: 0; border-top: 1px solid var(--rule); }
  .top-in { gap: 12px; }
  .mark { font-size: 1rem; }
  .langs a { padding: 4px 4px; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .detail { animation: none; }
}
@media print {
  .top, .tabs, .picks, .form, .foot .langs, body::before { display: none !important; }
  .explorer-panel, .detail { display: block !important; }
  .case-body { display: block; }
}