/* ИНЖЕНЕРНЫЙ СТИЛЬ КОНТУР•3D */
:root {
  --bg-dark: #060d18;
  --bg-card: #0b172a;
  --bg-panel: #0e1e38;
  --accent: #3a7bd5;
  --accent-light: #64b5f6;
  --text: #e2e8f0;
  --text-dim: #8a9bb8;
  --white: #ffffff;
  --border: #1e3356;
  --border-light: #2c4a7c;
  --grid-line: rgba(58, 123, 213, 0.08);
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  background-color: var(--bg-dark);
  color: var(--text);
  line-height: 1.6;
  overflow-x: hidden;
  position: relative;
}

/* СЕТКА НА ФОНЕ (ЧЕРТЕЖНЫЙ СТИЛЬ) */
body::before {
  content: "";
  position: fixed;
  top: 0; left: 0; width: 100vw; height: 100vh;
  background-image: 
    linear-gradient(var(--grid-line) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid-line) 1px, transparent 1px);
  background-size: 40px 40px;
  pointer-events: none;
  z-index: -1;
}

/* УГЛОВЫЕ МАРКЕРЫ (УГОЛКИ ЧЕРТЕЖА) */
.crop-mark {
  position: fixed;
  width: 20px;
  height: 20px;
  pointer-events: none;
  z-index: 999;
}
.crop-mark.tl { top: 10px; left: 10px; border-top: 1px solid var(--accent-light); border-left: 1px solid var(--accent-light); }
.crop-mark.tr { top: 10px; right: 10px; border-top: 1px solid var(--accent-light); border-right: 1px solid var(--accent-light); }
.crop-mark.bl { bottom: 10px; left: 10px; border-bottom: 1px solid var(--accent-light); border-left: 1px solid var(--accent-light); }
.crop-mark.br { bottom: 10px; right: 10px; border-bottom: 1px solid var(--accent-light); border-right: 1px solid var(--accent-light); }

/* БЛОК НАДПИСЕЙ НА ЧЕРТЕЖЕ В УГЛУ */
.title-block {
  position: fixed;
  bottom: 16px;
  right: 24px;
  background: var(--bg-card);
  border: 1px solid var(--border-light);
  padding: 6px 12px;
  font-family: monospace;
  font-size: 11px;
  color: var(--text-dim);
  display: flex;
  gap: 16px;
  z-index: 100;
  box-shadow: 0 4px 12px rgba(0,0,0,0.4);
}
.title-block b { color: var(--accent-light); }

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

/* ШАПКА */
.site-header {
  position: sticky;
  top: 0;
  background: rgba(6, 13, 24, 0.9);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
  z-index: 1000;
  padding: 16px 0;
}
.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.logo {
  font-family: monospace;
  font-weight: 700;
  font-size: 20px;
  color: var(--white);
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: 8px;
  letter-spacing: 1px;
}
.logo .mark {
  display: inline-block;
  width: 10px;
  height: 10px;
  background: var(--accent-light);
  box-shadow: 0 0 10px var(--accent);
}
.logo .dim { color: var(--accent-light); }

.main-nav {
  display: flex;
  align-items: center;
  gap: 32px;
}
.main-nav a {
  color: var(--text-dim);
  text-decoration: none;
  font-size: 14px;
  font-weight: 500;
  transition: color 0.2s;
}
.main-nav a:hover, .main-nav a.active {
  color: var(--white);
}
.main-nav a.cta {
  background: var(--accent);
  color: var(--white);
  padding: 8px 16px;
  border-radius: 2px;
  font-weight: 600;
}
.main-nav a.cta:hover {
  background: var(--accent-light);
  color: var(--bg-dark);
}

.nav-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  flex-direction: column;
  gap: 5px;
}
.nav-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--white);
}

/* HERO SECTION */
.hero {
  padding: 80px 0 60px;
  position: relative;
}
.hero-grid {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 48px;
  align-items: center;
}
.eyebrow {
  font-family: monospace;
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 2px;
  color: var(--accent-light);
  margin-bottom: 12px;
}
h1 {
  font-size: 42px;
  line-height: 1.15;
  color: var(--white);
  font-weight: 800;
  margin-bottom: 20px;
}
h1 .accent {
  color: var(--accent-light);
  text-shadow: 0 0 20px rgba(100, 181, 246, 0.3);
}
.hero-lead {
  font-size: 16px;
  color: var(--text-dim);
  margin-bottom: 32px;
  max-width: 580px;
}
.hero-actions {
  display: flex;
  gap: 16px;
  margin-bottom: 40px;
}
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 24px;
  background: var(--bg-card);
  color: var(--white);
  border: 1px solid var(--border-light);
  text-decoration: none;
  font-weight: 600;
  font-size: 14px;
  border-radius: 2px;
  transition: all 0.2s;
}
.btn:hover {
  border-color: var(--accent-light);
  background: var(--bg-panel);
}
.btn.primary {
  background: var(--accent);
  border-color: var(--accent);
}
.btn.primary:hover {
  background: var(--accent-light);
  color: var(--bg-dark);
}

.hero-stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
  border-top: 1px solid var(--border);
  padding-top: 24px;
}
.stat b {
  display: block;
  font-size: 24px;
  font-family: monospace;
  color: var(--white);
}
.stat span {
  font-size: 12px;
  color: var(--text-dim);
}

/* 3D SCENE BACKGROUND / HERO ANIMATION */
.scene3d {
  position: relative;
  height: 380px;
  background: radial-gradient(circle at center, rgba(14,30,56,0.8) 0%, rgba(6,13,24,0.95) 100%);
  border: 1px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  perspective: 1000px;
}
.stage {
  position: relative;
  width: 160px;
  height: 160px;
  transform-style: preserve-3d;
  animation: rotateStage 20s infinite linear;
}
@keyframes rotateStage {
  0% { transform: rotateX(-20deg) rotateY(0deg); }
  100% { transform: rotateX(-20deg) rotateY(360deg); }
}
.solid {
  position: absolute;
  top: 50%; left: 50%;
  transform-style: preserve-3d;
}
.cube3d {
  width: 80px; height: 80px;
  margin: -40px 0 0 -40px;
  transform-style: preserve-3d;
  animation: floatCube 4s ease-in-out infinite alternate;
}
@keyframes floatCube {
  0% { transform: translateY(-10px) rotateX(15deg) rotateY(15deg); }
  100% { transform: translateY(10px) rotateX(45deg) rotateY(45deg); }
}
.face {
  position: absolute;
  width: 80px; height: 80px;
  background: rgba(58, 123, 213, 0.1);
  border: 1px solid var(--accent-light);
}
.f-front  { transform: translateZ(40px); }
.f-back   { transform: rotateY(180deg) translateZ(40px); }
.f-right  { transform: rotateY(90deg) translateZ(40px); }
.f-left   { transform: rotateY(-90deg) translateZ(40px); }
.f-top    { transform: rotateX(90deg) translateZ(40px); }
.f-bottom { transform: rotateX(-90deg) translateZ(40px); }

.bolt3d {
  width: 50px; height: 100px;
  margin: -50px 0 0 -25px;
  background: linear-gradient(90deg, #1e3356, #3a7bd5, #1e3356);
  border: 1px solid var(--accent-light);
  transform: translateZ(70px) rotateX(45deg);
}

.floor-grid {
  position: absolute;
  bottom: 0; width: 100%; height: 60px;
  background-image: linear-gradient(to top, rgba(58,123,213,0.15), transparent);
  border-top: 1px solid var(--border-light);
}

/* SECTIONS & PANELS */
.tight {
  padding: 60px 0;
}
.section-head {
  margin-bottom: 40px;
}
.section-head h2 {
  font-size: 32px;
  color: var(--white);
  margin-bottom: 12px;
}
.section-head p {
  color: var(--text-dim);
  max-width: 680px;
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}
.grid-2 {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}

.panel {
  background: var(--bg-card);
  border: 1px solid var(--border);
  padding: 32px;
  position: relative;
  transition: border-color 0.2s;
}
.panel:hover {
  border-color: var(--border-light);
}
.panel svg {
  width: 32px; height: 32px;
  stroke: var(--accent-light);
  margin-bottom: 16px;
}
.panel .num {
  display: block;
  font-family: monospace;
  font-size: 11px;
  color: var(--accent-light);
  margin-bottom: 8px;
  letter-spacing: 1px;
}
.panel h3 {
  font-size: 20px;
  color: var(--white);
  margin-bottom: 12px;
}
.panel p {
  font-size: 14px;
  color: var(--text-dim);
}

.tag-row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 20px;
}
.tag {
  font-family: monospace;
  font-size: 11px;
  background: var(--bg-dark);
  border: 1px solid var(--border);
  color: var(--accent-light);
  padding: 4px 10px;
}

/* PROCESS STRIP */
.process-strip {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
}
.process-step {
  background: var(--bg-card);
  border: 1px solid var(--border);
  padding: 24px;
  position: relative;
}
.process-step .idx {
  font-family: monospace;
  font-size: 28px;
  font-weight: 700;
  color: var(--border-light);
  display: block;
  margin-bottom: 12px;
}
.process-step h4 {
  font-size: 16px;
  color: var(--white);
  margin-bottom: 8px;
}
.process-step p {
  font-size: 13px;
  color: var(--text-dim);
}

/* SKETCHES GALLERY (Эскизы серо-белые) */
.sketch-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 32px;
}
.sketch-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  padding: 24px;
}
.sketch-card h3 {
  font-size: 18px;
  color: var(--white);
  margin-bottom: 16px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.sketch-viewport {
  background: #0d1b31;
  border: 1px solid var(--border-light);
  padding: 16px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 16px;
}
.sketch-viewport svg {
  width: 100%;
  max-height: 220px;
}
/* Чертёжные стили линий SVG: серо-белые */
.stroke-white { stroke: #ffffff; }
.stroke-gray  { stroke: #a0aec0; }
.dim-text     { fill: #cbd5e0; font-family: monospace; font-size: 11px; }
.fill-none    { fill: none; }
.hatch line   { stroke: #718096; stroke-width: 0.5; }

.sketch-info {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 8px;
  font-size: 12px;
  border-top: 1px solid var(--border);
  padding-top: 12px;
}
.sketch-info div {
  font-family: monospace;
}
.sketch-info b {
  display: block;
  color: var(--text-dim);
  font-size: 10px;
  text-transform: uppercase;
}
.sketch-info span {
  color: var(--white);
}

/* ФОРМА И КОНТАКТЫ */
.engineering-form .form-group {
  margin-bottom: 20px;
}
.engineering-form label {
  display: block;
  font-size: 13px;
  font-weight: 500;
  color: var(--text);
  margin-bottom: 8px;
}
.engineering-form input[type="text"],
.engineering-form select,
.engineering-form textarea {
  width: 100%;
  background: var(--bg-dark);
  border: 1px solid var(--border-light);
  color: var(--white);
  padding: 12px 16px;
  font-size: 14px;
  border-radius: 2px;
  outline: none;
  font-family: inherit;
  transition: border-color 0.2s;
}
.engineering-form input:focus,
.engineering-form select:focus,
.engineering-form textarea:focus {
  border-color: var(--accent-light);
}
.file-upload-group input[type="file"] {
  display: none;
}
.file-label {
  display: block;
  border: 1px dashed var(--border-light);
  padding: 16px;
  text-align: center;
  cursor: pointer;
  color: var(--accent-light);
  font-size: 13px;
  transition: background 0.2s;
}
.file-label:hover {
  background: rgba(58,123,213,0.05);
}

/* ФУТЕР */
.site-footer {
  border-top: 1px solid var(--border);
  background: #040810;
  padding: 60px 0 30px;
  margin-top: 60px;
}
.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 40px;
  margin-bottom: 40px;
}
.site-footer h4 {
  font-size: 14px;
  color: var(--white);
  margin-bottom: 16px;
  font-family: monospace;
  letter-spacing: 1px;
}
.site-footer ul {
  list-style: none;
}
.site-footer ul li {
  margin-bottom: 10px;
}
.site-footer ul a {
  color: var(--text-dim);
  text-decoration: none;
  font-size: 14px;
}
.site-footer ul a:hover {
  color: var(--white);
}
.footer-bottom {
  border-top: 1px solid var(--border);
  padding-top: 20px;
  display: flex;
  justify-content: space-between;
  font-size: 12px;
  color: var(--text-dim);
  font-family: monospace;
}

/* АДАПТИВ */
@media (max-width: 900px) {
  .hero-grid, .grid-3, .grid-2, .process-strip, .sketch-grid, .footer-grid {
    grid-template-columns: 1fr;
  }
  .main-nav {
    display: none;
    position: absolute;
    top: 100%; left: 0; width: 100%;
    background: var(--bg-card);
    flex-direction: column;
    padding: 24px;
    border-bottom: 1px solid var(--border);
  }
  .main-nav.open {
    display: flex;
  }
  .nav-toggle {
    display: flex;
  }
  .title-block {
    display: none;
  }
}