/* ============================================================
   ПТК ИНТЕЛЛ ЭЛЕКТРО — Concept 1 «Инженерная документация»
   Светлая чертёжная система: бумага, тушь, штампы, выносные линии
   ============================================================ */

:root {
  --paper: #f7f5ef;
  --paper-2: #fffdf7;
  --ink: #1c2a42;
  --ink-soft: #4c5872;
  --line: #d9d4c4;
  --line-ink: #b7b1a0;
  --accent: #1e648f;
  --accent-soft: #e3edf4;
  --stamp: #a8462b;

  --sans: 'Golos Text', 'Segoe UI', sans-serif;
  --mono: 'IBM Plex Mono', 'Courier New', monospace;

  --wrap: 1180px;
  --gutter: 24px;
  --radius: 2px;
}

@media (prefers-color-scheme: dark) { :root { color-scheme: light; } }

* { margin: 0; padding: 0; box-sizing: border-box; }

html { scroll-behavior: smooth; }
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation: none !important; transition: none !important; }
}

body {
  font-family: var(--sans);
  font-size: 17px;
  line-height: 1.65;
  color: var(--ink);
  background: var(--paper);
  -webkit-font-smoothing: antialiased;
}

.mono { font-family: var(--mono); }

h1, h2, h3 { line-height: 1.15; font-weight: 700; letter-spacing: -0.01em; }

a { color: var(--accent); }
a:hover { color: var(--ink); }

img, svg { max-width: 100%; }

.visually-hidden {
  position: absolute; width: 1px; height: 1px;
  clip-path: inset(50%); overflow: hidden; white-space: nowrap;
}

.skip-link {
  position: absolute; left: 16px; top: -60px;
  z-index: 100; padding: 10px 16px;
  background: var(--ink); color: var(--paper);
  font-family: var(--mono); font-size: 14px; text-decoration: none;
  transition: top .2s ease;
}
.skip-link:focus { top: 12px; color: var(--paper); }

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
}

/* якоря не уходят под липкий header */
section[id] { scroll-margin-top: 84px; }

/* ---------- контейнер и «листы» ---------- */

.wrap { max-width: var(--wrap); margin: 0 auto; padding: 0 var(--gutter); }

.sheet {
  max-width: var(--wrap);
  margin: 0 auto;
  padding: 72px var(--gutter) 64px;
  position: relative;
}
.sheet + .sheet { padding-top: 40px; }

/* угловые реперные метки листа */
.sheet::before,
.sheet::after {
  content: ""; position: absolute; width: 14px; height: 14px;
  border-color: var(--line-ink); border-style: solid;
  opacity: .8; pointer-events: none;
}
.sheet::before { left: calc(var(--gutter) - 7px); top: 8px; border-width: 1px 0 0 1px; }
.sheet::after  { right: calc(var(--gutter) - 7px); top: 8px; border-width: 1px 1px 0 0; }

.sheet-head {
  display: grid;
  grid-template-columns: 140px 1fr auto;
  gap: 8px 24px;
  align-items: baseline;
  border-top: 1px solid var(--ink);
  padding-top: 18px;
  margin-bottom: 36px;
}
.sheet-code {
  font-size: 13px; letter-spacing: .14em; text-transform: uppercase;
  color: var(--stamp); font-weight: 600;
}
.sheet-head h2 { font-size: clamp(26px, 3.4vw, 40px); }
.sheet-note {
  font-size: 12px; letter-spacing: .12em; text-transform: uppercase;
  color: var(--ink-soft); justify-self: end; text-align: right;
}

.section-intro { max-width: 640px; color: var(--ink-soft); margin-bottom: 32px; }

.lead { font-size: clamp(18px, 2vw, 21px); font-weight: 500; }
.note-line {
  margin-top: 18px; font-size: 12px; letter-spacing: .1em; text-transform: uppercase;
  color: var(--ink-soft); border-left: 2px solid var(--stamp); padding-left: 12px;
}

/* ---------- header ---------- */

.site-header {
  position: sticky; top: 0; z-index: 50;
  background: var(--paper);
  border-bottom: 1px solid var(--ink);
}
.header-inner {
  max-width: var(--wrap); margin: 0 auto;
  padding: 14px var(--gutter);
  display: flex; align-items: center; justify-content: space-between; gap: 24px;
}
.wordmark { text-decoration: none; color: var(--ink); display: flex; flex-direction: column; }
.wordmark-name { font-weight: 800; font-size: 17px; letter-spacing: .04em; }
.wordmark-sub { font-size: 10px; letter-spacing: .18em; text-transform: uppercase; color: var(--ink-soft); }

.nav-toggle {
  display: none;
  width: 44px; height: 40px;
  border: 1px solid var(--ink); background: transparent; cursor: pointer;
  position: relative; border-radius: var(--radius);
}
.nav-toggle-bar {
  position: absolute; left: 11px; right: 11px; height: 2px;
  background: var(--ink); transition: transform .25s ease, opacity .25s ease;
}
.nav-toggle-bar:nth-child(1) { top: 12px; }
.nav-toggle-bar:nth-child(2) { top: 19px; }
.nav-toggle-bar:nth-child(3) { top: 26px; }
.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(2) { opacity: 0; }
.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

.nav-list {
  display: flex; align-items: center; gap: 26px;
  list-style: none;
}
.nav-list a:not(.btn) {
  font-size: 14px; text-decoration: none; color: var(--ink);
  padding: 4px 0; border-bottom: 1px solid transparent;
}
.nav-list a:not(.btn):hover { color: var(--accent); border-bottom-color: var(--accent); }

/* ---------- кнопки ---------- */

.btn {
  display: inline-block;
  font-family: var(--sans); font-size: 15px; font-weight: 600;
  padding: 13px 26px; border-radius: var(--radius);
  text-decoration: none; cursor: pointer;
  border: 1px solid var(--ink);
  transition: transform .15s ease, box-shadow .15s ease, background-color .15s ease, color .15s ease;
}
.btn-primary { background: var(--ink); color: var(--paper); }
.btn-ghost { background: transparent; color: var(--ink); }
.btn:hover { transform: translate(-2px, -2px); box-shadow: 3px 3px 0 var(--accent); }
.btn:active { transform: translate(0, 0); box-shadow: 1px 1px 0 var(--accent); }
.btn-sm { padding: 9px 18px; font-size: 13px; }

.arrow-link { text-decoration: none; font-weight: 600; font-size: 15px; }
.arrow-link span { display: inline-block; transition: transform .2s ease; }
.arrow-link:hover span { transform: translateX(5px); }

/* ---------- hero: титульный лист ---------- */

.hero {
  padding-top: 64px; padding-bottom: 40px;
  background-image:
    linear-gradient(var(--line) 1px, transparent 1px),
    linear-gradient(90deg, var(--line) 1px, transparent 1px);
  background-size: 34px 34px;
  background-position: center top;
}
.hero::before, .hero::after { display: none; }

.stamp {
  position: absolute; top: 34px; right: var(--gutter);
  transform: rotate(-5deg);
  border: 2px solid var(--stamp); color: var(--stamp);
  font-size: 12px; font-weight: 600; letter-spacing: .22em; text-transform: uppercase;
  padding: 5px 12px; opacity: .75; pointer-events: none;
}

.hero-kicker {
  font-size: 13px; letter-spacing: .18em; text-transform: uppercase;
  color: var(--ink-soft); margin-bottom: 22px;
}
.hero-title {
  font-size: clamp(34px, 5.4vw, 66px);
  font-weight: 800; letter-spacing: -0.02em;
  max-width: 15ch;
  margin-bottom: 44px;
}

.hero-grid {
  display: grid; grid-template-columns: minmax(0, 1.15fr) minmax(0, 1fr);
  gap: 44px; align-items: start;
}

.hero-actions { display: flex; flex-wrap: wrap; gap: 14px; margin-top: 26px; }

/* штамп-титул */
.titleblock {
  border: 2px solid var(--ink);
  background: var(--paper-2);
  box-shadow: 0 0 0 1px var(--paper-2), 4px 4px 0 rgba(28, 42, 66, .12);
}
.tb-row {
  display: grid; grid-template-columns: 128px 1fr;
  border-bottom: 1px solid var(--ink);
}
.tb-row:last-child { border-bottom: 0; }
.tb-label {
  font-size: 11px; letter-spacing: .1em; text-transform: uppercase;
  color: var(--ink-soft); padding: 12px 14px;
  border-right: 1px solid var(--ink);
}
.tb-value { padding: 12px 16px; font-size: 15px; font-weight: 500; }

/* однолинейная схема */
.schematic { margin-top: 56px; border-top: 1px solid var(--line); padding-top: 32px; }
.schematic svg { width: 100%; height: auto; display: block; }
.wire { stroke: var(--ink); stroke-width: 1.5; }
.wire-accent { stroke: var(--accent); stroke-width: 2.5; }
.wire-fig { fill: none; }
.mono-label {
  font-family: var(--mono); font-size: 13px; fill: var(--ink-soft);
  text-anchor: middle; letter-spacing: .08em;
}
.mono-label-accent { fill: var(--accent); font-weight: 600; }
.schematic-caption {
  margin-top: 18px; font-size: 12px; letter-spacing: .08em;
  color: var(--ink-soft); text-align: center; text-transform: uppercase;
}

/* анимация начертания схемы (только при включённой анимации) */
.js-anim .wire { stroke-dasharray: 1; stroke-dashoffset: 1; }
.js-anim .is-drawn .wire { transition: stroke-dashoffset 1.1s ease .2s; stroke-dashoffset: 0; }
.js-anim .is-drawn .wire-accent { transition-delay: .8s; }
.js-anim .is-drawn .mono-label { animation: fadeLabel .5s ease 1.5s both; }
.js-anim .mono-label { opacity: 1; }
.js-anim .is-drawn .mono-label { opacity: 1; }
@keyframes fadeLabel { from { opacity: 0; } to { opacity: 1; } }

/* ---------- направления ---------- */

.directions-grid {
  display: grid; grid-template-columns: 1fr 1fr; gap: 28px;
}
.direction-card {
  border: 1px solid var(--line-ink);
  background: var(--paper-2);
  padding: 34px 30px;
  position: relative;
  transition: border-color .2s ease, box-shadow .2s ease;
}
.direction-card::before {
  content: ""; position: absolute; top: -1px; left: -1px;
  width: 46px; height: 3px; background: var(--accent);
}
.direction-card:hover { border-color: var(--ink); box-shadow: 5px 5px 0 rgba(30, 100, 143, .18); }
.direction-code {
  display: flex; align-items: center; justify-content: space-between;
  margin-bottom: 22px;
}
.direction-code p { font-size: 12px; letter-spacing: .16em; color: var(--stamp); font-weight: 600; }
.dir-symbol { width: 58px; height: 58px; stroke: var(--ink); stroke-width: 2; fill: none; }
.direction-card h3 { font-size: 24px; margin-bottom: 12px; }
.direction-card p { color: var(--ink-soft); margin-bottom: 20px; }

/* ---------- разделы ЭМ / ЭЗ ---------- */

.section-grid {
  display: grid; grid-template-columns: minmax(0, 1.5fr) minmax(0, 1fr);
  gap: 44px; align-items: start;
}
.section-text p + p { margin-top: 16px; }

.side-block {
  border: 1px solid var(--line-ink);
  background: var(--paper-2);
  padding: 26px 24px;
}
.side-title {
  font-size: 11px; letter-spacing: .16em; text-transform: uppercase;
  color: var(--ink-soft); margin-bottom: 14px;
}
.side-block .side-title + .side-title { margin-top: 26px; }
.side-text { font-size: 15px; color: var(--ink-soft); }

.chip-list { list-style: none; display: flex; flex-wrap: wrap; gap: 10px; }
.chip-list li {
  font-size: 13px; font-weight: 500;
  border: 1px solid var(--ink); padding: 7px 14px; border-radius: var(--radius);
}

/* ---------- спецификация ---------- */

.spec-list { border: 1px solid var(--ink); background: var(--paper-2); }
.spec-row {
  display: grid;
  grid-template-columns: 64px 1.5fr 1.3fr 1.3fr 190px;
  border-bottom: 1px solid var(--line-ink);
}
.spec-row:last-child { border-bottom: 0; }
.spec-head {
  background: var(--ink); color: var(--paper);
  font-size: 11px; letter-spacing: .12em; text-transform: uppercase;
  padding: 12px 16px;
}
.spec-row .cell { padding: 16px; border-right: 1px solid var(--line-ink); display: flex; flex-direction: column; gap: 4px; justify-content: center; }
.spec-row .cell:last-child { border-right: 0; }
.cell-tag { display: none; }
.cell-val { font-size: 15px; }
.cell-dash { color: var(--line-ink); }
.cell-status { font-size: 12px; color: var(--stamp); letter-spacing: .04em; }
.spec-ghost { justify-items: start; }
.spec-ghost .cell-val {
  grid-column: 1 / -1; padding: 18px 16px;
  font-size: 12px; color: var(--ink-soft); letter-spacing: .06em;
  border: 0;
}

/* ---------- принципы ---------- */

.qa-list { border-top: 1px solid var(--ink); }
.qa-row {
  display: grid; grid-template-columns: 230px 1fr;
  gap: 24px; padding: 20px 0;
  border-bottom: 1px solid var(--line);
}
.qa-row dt {
  font-size: 14px; font-weight: 600; letter-spacing: .18em; text-transform: uppercase;
  color: var(--accent);
}
.qa-row dd { color: var(--ink-soft); max-width: 60ch; }

/* ---------- фотофиксация ---------- */

.frames-grid {
  display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px;
}
.frame {
  border: 1px solid var(--ink); background: var(--paper-2);
  padding: 12px; margin: 0;
}
.frame-media {
  min-height: 190px;
  display: flex; align-items: center; justify-content: center;
  text-align: center;
  border: 1px dashed var(--line-ink);
  background: repeating-linear-gradient(45deg, transparent 0 12px, rgba(28,42,66,.045) 12px 13px);
  padding: 18px;
}
.frame-media .mono {
  font-size: 11px; letter-spacing: .12em; text-transform: uppercase;
  color: var(--ink-soft); max-width: 22ch;
}
.frame figcaption {
  display: flex; justify-content: space-between; gap: 12px;
  margin-top: 12px;
  font-size: 11px; letter-spacing: .08em; text-transform: uppercase;
  color: var(--ink-soft);
}

/* ---------- география ---------- */

.geo-list {
  list-style: none;
  display: grid; grid-template-columns: repeat(5, 1fr);
  gap: 12px; margin-bottom: 28px;
  border-top: 1px solid var(--ink); border-bottom: 1px solid var(--line);
}
.geo-city {
  padding: 20px 4px 16px;
  font-weight: 700; font-size: 17px;
  display: flex; flex-direction: column; gap: 10px;
}
.geo-node {
  width: 10px; height: 10px; border: 2px solid var(--ink); border-radius: 50%;
  background: var(--accent); display: inline-block;
}

/* ---------- форма и контакты ---------- */

.contact-grid {
  display: grid; grid-template-columns: minmax(0, 1.4fr) minmax(0, 1fr);
  gap: 44px; align-items: start;
}
.tz-form .field { margin-bottom: 22px; }
.tz-form label {
  display: block; font-size: 12px; font-weight: 600; letter-spacing: .12em;
  text-transform: uppercase; margin-bottom: 8px; color: var(--ink);
}
.tz-form input, .tz-form select, .tz-form textarea {
  width: 100%;
  font-family: var(--sans); font-size: 16px; color: var(--ink);
  background: var(--paper-2);
  border: 1px solid var(--line-ink); border-radius: var(--radius);
  padding: 12px 14px;
  transition: border-color .15s ease;
}
.tz-form input:hover, .tz-form select:hover, .tz-form textarea:hover { border-color: var(--ink); }
.tz-form input:focus, .tz-form select:focus, .tz-form textarea:focus {
  border-color: var(--accent); outline: 2px solid var(--accent-soft);
}
.tz-form input[aria-invalid="true"], .tz-form textarea[aria-invalid="true"] {
  border-color: var(--stamp);
}
.field-error { font-size: 11px; color: var(--stamp); min-height: 16px; margin-top: 6px; letter-spacing: .04em; }

.form-demo-note {
  font-size: 12px; line-height: 1.6; color: var(--ink-soft);
  border: 1px dashed var(--line-ink); padding: 12px 16px; margin-bottom: 26px;
}
.form-notice {
  margin-top: 22px;
  border: 1px solid var(--stamp);
  padding: 16px 18px;
  font-size: 13px; line-height: 1.6; color: var(--ink);
  background: var(--paper-2);
}
.form-notice strong { color: var(--stamp); }
.form-notice p + p { margin-top: 8px; }

.contact-block { position: sticky; top: 96px; }
.contact-list { display: flex; flex-direction: column; gap: 14px; }
.contact-list dt { font-size: 11px; letter-spacing: .16em; text-transform: uppercase; color: var(--ink-soft); }
.contact-list dd { font-size: 15px; font-weight: 500; }
.contact-list a { font-weight: 600; }

/* ---------- footer ---------- */

.site-footer { border-top: 2px solid var(--ink); margin-top: 48px; }
.footer-inner {
  max-width: var(--wrap); margin: 0 auto; padding: 44px var(--gutter) 34px;
  display: grid; grid-template-columns: 1.4fr 1fr 1fr; gap: 40px;
}
.footer-note { font-size: 11px; letter-spacing: .12em; text-transform: uppercase; color: var(--ink-soft); margin-top: 10px; }
.footer-nav { list-style: none; display: flex; flex-direction: column; gap: 8px; }
.footer-nav a { text-decoration: none; color: var(--ink); font-size: 15px; }
.footer-nav a:hover { color: var(--accent); }
.footer-col p a { font-weight: 600; }
.footer-bottom {
  border-top: 1px solid var(--line-ink);
  max-width: var(--wrap); margin: 0 auto;
  padding: 16px var(--gutter) 22px;
  display: flex; flex-wrap: wrap; gap: 8px 28px; justify-content: space-between;
  font-size: 11px; letter-spacing: .1em; text-transform: uppercase; color: var(--ink-soft);
}

/* ---------- reveal ---------- */

.js-anim .reveal { opacity: 0; transform: translateY(16px); transition: opacity .6s ease, transform .6s ease; }
.js-anim .reveal.is-visible { opacity: 1; transform: none; }

/* ============================================================
   Адаптив
   ============================================================ */

@media (max-width: 1020px) {
  .spec-row { grid-template-columns: 56px 1.4fr 1.2fr 1.2fr 150px; }
  .qa-row { grid-template-columns: 180px 1fr; }
}

@media (max-width: 900px) {
  .sheet { padding: 52px var(--gutter) 44px; }
  .hero-grid, .section-grid, .contact-grid, .directions-grid { grid-template-columns: 1fr; }
  .frames-grid { grid-template-columns: repeat(2, 1fr); }
  .geo-list { grid-template-columns: repeat(3, 1fr); }
  .titleblock { box-shadow: none; }
  .contact-block { position: static; }
  .stamp { display: none; }
  .sheet-head { grid-template-columns: 1fr; }
  .sheet-note { justify-self: start; }

  /* мобильная навигация */
  .nav-toggle { display: block; }
  .site-nav {
    position: absolute; top: 100%; left: 0; right: 0;
    background: var(--paper);
    border-bottom: 1px solid var(--ink);
    display: none;
    padding: 10px var(--gutter) 22px;
  }
  .site-nav.is-open { display: block; }
  .nav-list { flex-direction: column; align-items: flex-start; gap: 16px; }
  .nav-cta { margin-top: 6px; }
}

@media (max-width: 640px) {
  body { font-size: 16px; }
  .hero { padding-top: 40px; }
  .hero-title { margin-bottom: 28px; }
  .schematic .mono-label { display: none; }
  .schematic-caption { text-align: left; }
  .frames-grid { grid-template-columns: 1fr; }
  .geo-list { grid-template-columns: repeat(2, 1fr); }
  .tb-row { grid-template-columns: 108px 1fr; }

  /* спецификация превращается в карточки */
  .spec-row { display: block; padding: 14px 4px; }
  .spec-row .cell { border-right: 0; border-bottom: 1px solid var(--line); padding: 10px 2px; }
  .spec-row .cell:last-child { border-bottom: 0; }
  .spec-head { display: none; }
  .cell-tag {
    display: block; font-size: 10px; letter-spacing: .14em;
    text-transform: uppercase; color: var(--ink-soft);
  }
  .qa-row { grid-template-columns: 1fr; gap: 6px; }
  .footer-inner { grid-template-columns: 1fr; gap: 26px; }
  .footer-bottom { flex-direction: column; }
}