/* =========================================================
   BiliBom — design system
   ========================================================= */

:root {
  /* Palette — временная нейтральная, легко заменить */
  --color-bg: #f7f4ee;
  --color-surface: #ffffff;
  --color-ink: #17140f;
  --color-muted: #6f6a60;
  --color-line: #e4ddcf;
  --color-accent: #c8481d;
  --color-accent-ink: #ffffff;
  --color-dark: #17140f;
  --color-dark-ink: #f4f0e6;
  --color-dark-muted: #a49c8d;

  --container: 1240px;
  --container-narrow: 780px;

  --space-1: 0.5rem;
  --space-2: 1rem;
  --space-3: 1.5rem;
  --space-4: 2.5rem;
  --space-5: 4rem;
  --space-6: 6rem;
  --space-7: 9rem;

  --radius-sm: 3px;
  --radius-md: 6px;

  --font-body: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-display: var(--font-body);

  --step-0: clamp(1rem, 0.95rem + 0.2vw, 1.125rem);
  --step-1: clamp(1.25rem, 1.15rem + 0.5vw, 1.5rem);
  --step-2: clamp(1.75rem, 1.5rem + 1vw, 2.25rem);
  --step-3: clamp(2.25rem, 1.8rem + 2vw, 3.25rem);
  --step-4: clamp(2.75rem, 2rem + 3.2vw, 4.75rem);

  --transition-fast: 180ms ease;
  --transition-medium: 420ms cubic-bezier(0.22, 1, 0.36, 1);
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--color-bg);
  color: var(--color-ink);
  font-family: var(--font-body);
  font-size: var(--step-0);
  line-height: 1.55;
  overflow-x: hidden;
}

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

a { color: inherit; }

h1, h2, h3, h4 {
  font-family: var(--font-display);
  line-height: 1.08;
  letter-spacing: -0.01em;
  margin: 0 0 var(--space-2);
  font-weight: 700;
}

h1 { font-size: var(--step-4); }
h2 { font-size: var(--step-3); }
h3 { font-size: var(--step-2); }
h4 { font-size: var(--step-1); }

p { margin: 0 0 var(--space-2); color: var(--color-ink); }

.container {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 var(--space-3);
}

.container-narrow {
  max-width: var(--container-narrow);
  margin: 0 auto;
  padding: 0 var(--space-3);
}

.visually-hidden {
  position: absolute;
  width: 1px; height: 1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
}

.skip-link {
  position: absolute;
  left: -999px;
  top: 0;
  background: var(--color-accent);
  color: var(--color-accent-ink);
  padding: 0.75rem 1.25rem;
  z-index: 200;
  border-radius: 0 0 var(--radius-sm) 0;
}
.skip-link:focus {
  left: 0;
}

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

/* Eyebrow / labels */
.eyebrow {
  display: inline-block;
  font-size: 0.8rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--color-accent);
  font-weight: 600;
  margin-bottom: var(--space-1);
}

.section-head {
  max-width: 640px;
  margin-bottom: var(--space-4);
}
.section-head.center { margin-left: auto; margin-right: auto; text-align: center; }

.text-muted { color: var(--color-muted); }

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.9rem 1.75rem;
  border-radius: var(--radius-sm);
  font-weight: 600;
  text-decoration: none;
  border: 1px solid transparent;
  cursor: pointer;
  font-size: 0.95rem;
  transition: transform var(--transition-fast), background var(--transition-fast), color var(--transition-fast), border-color var(--transition-fast);
}
.btn:hover { transform: translateY(-1px); }
.btn-primary {
  background: var(--color-accent);
  color: var(--color-accent-ink);
}
.btn-primary:hover { background: color-mix(in srgb, var(--color-accent) 85%, black); }
.btn-ghost {
  background: transparent;
  color: inherit;
  border-color: var(--color-line);
}
.btn-ghost:hover { border-color: var(--color-accent); color: var(--color-accent); }
.btn-link {
  background: none;
  padding: 0;
  border: none;
  text-underline-offset: 4px;
  text-decoration: underline;
}
.btn-block { width: 100%; justify-content: center; }

/* Header */
.site-header {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  padding: var(--space-2) 0;
  background: transparent;
  transition: background var(--transition-medium), box-shadow var(--transition-medium), padding var(--transition-medium);
}
.site-header.is-solid {
  background: rgba(247, 244, 238, 0.92);
  backdrop-filter: blur(6px);
  box-shadow: 0 1px 0 var(--color-line);
  padding: var(--space-1) 0;
}
.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-3);
}
.logo {
  font-size: 1.35rem;
  font-weight: 800;
  letter-spacing: -0.02em;
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: 0.6rem;
}
.logo img { height: 36px; width: auto; }

.main-nav { display: flex; align-items: center; gap: var(--space-4); }
.main-nav ul {
  list-style: none;
  display: flex;
  gap: var(--space-3);
  margin: 0; padding: 0;
}
.main-nav a {
  text-decoration: none;
  font-weight: 500;
  font-size: 0.95rem;
  padding: 0.3rem 0;
  border-bottom: 2px solid transparent;
  transition: border-color var(--transition-fast);
}
.main-nav a:hover { border-color: var(--color-accent); }

.nav-toggle {
  display: none;
  background: none;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-sm);
  padding: 0.5rem 0.7rem;
  cursor: pointer;
}
.nav-toggle span, .nav-toggle span::before, .nav-toggle span::after {
  content: "";
  display: block;
  width: 20px;
  height: 2px;
  background: currentColor;
  position: relative;
  transition: transform var(--transition-fast);
}
.nav-toggle span::before { position: absolute; top: -6px; }
.nav-toggle span::after { position: absolute; top: 6px; }

/* Hero */
.hero {
  position: relative;
  min-height: 92vh;
  display: flex;
  align-items: flex-end;
  padding: var(--space-7) 0 var(--space-5);
  background: var(--color-dark);
  color: var(--color-dark-ink);
  background-size: cover;
  background-position: center;
  isolation: isolate;
}
.hero::after {
  content: "";
  position: absolute; inset: 0;
  background: linear-gradient(180deg, rgba(23,20,15,0.25) 0%, rgba(23,20,15,0.75) 100%);
  z-index: -1;
}
.hero-inner { max-width: 760px; }
.hero h1 { font-size: var(--step-4); margin-bottom: var(--space-2); }
.hero p.lead { font-size: var(--step-1); color: var(--color-dark-muted); max-width: 560px; }
.hero-actions { display: flex; align-items: center; gap: var(--space-3); margin-top: var(--space-3); flex-wrap: wrap; }
.hero-actions .btn-ghost { color: var(--color-dark-ink); border-color: rgba(244,240,230,0.35); }
.hero-actions .btn-ghost:hover { border-color: var(--color-dark-ink); color: var(--color-dark-ink); }

/* Sections */
section { padding: var(--space-6) 0; }
.section-alt { background: var(--color-surface); }
.section-dark { background: var(--color-dark); color: var(--color-dark-ink); }
.section-dark .text-muted { color: var(--color-dark-muted); }
.section-dark .eyebrow { color: color-mix(in srgb, var(--color-accent) 70%, white); }

/* Editorial split layout */
.split {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-5);
  align-items: center;
}
.split.reverse .split-media { order: 2; }
.split-media img { border-radius: var(--radius-md); width: 100%; height: auto; object-fit: cover; }

/* Asymmetric grid for direction blocks */
.grid-asymmetric {
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  gap: var(--space-3);
}
.grid-asymmetric .card-wide { grid-column: span 4; }
.grid-asymmetric .card-narrow { grid-column: span 2; }

/* Cards */
.card {
  background: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-md);
  overflow: hidden;
  display: flex;
  flex-direction: column;
  transition: transform var(--transition-fast), box-shadow var(--transition-fast);
}
.card:hover { transform: translateY(-3px); box-shadow: 0 12px 30px -18px rgba(23,20,15,0.35); }
.card-media { aspect-ratio: 4/5; background: var(--color-line); overflow: hidden; }
.card-media img { width: 100%; height: 100%; object-fit: cover; }
.card-body { padding: var(--space-3); flex: 1; display: flex; flex-direction: column; }
.card-body h3 { font-size: 1.25rem; margin-bottom: 0.4rem; }
.card-body .btn-link { margin-top: auto; align-self: flex-start; }

.card-flat {
  padding: var(--space-3);
  border-top: 1px solid var(--color-line);
}
.card-flat:first-child { border-top: none; }

/* Product / category grid */
.grid {
  display: grid;
  gap: var(--space-3);
}
.grid-2 { grid-template-columns: repeat(2, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }

/* Advantages */
.advantage-list { list-style: none; margin: 0; padding: 0; display: grid; grid-template-columns: repeat(3, 1fr); gap: var(--space-4); }
.advantage-list li { display: flex; gap: var(--space-2); }
.advantage-icon { width: 44px; height: 44px; border-radius: 50%; background: var(--color-line); flex-shrink: 0; object-fit: cover; }

/* Process steps */
.steps { counter-reset: step; list-style: none; margin: 0; padding: 0; }
.step {
  display: grid;
  grid-template-columns: 80px 1fr;
  gap: var(--space-3);
  padding: var(--space-3) 0;
  border-top: 1px solid var(--color-line);
}
.step:first-child { border-top: none; }
.step-number {
  counter-increment: step;
  font-size: 2rem;
  font-weight: 800;
  color: var(--color-accent);
  font-variant-numeric: tabular-nums;
}
.step-number::before { content: counter(step, decimal-leading-zero); }

/* Testimonials */
.testimonial-scroll {
  display: flex;
  gap: var(--space-3);
  overflow-x: auto;
  padding-bottom: var(--space-2);
  scroll-snap-type: x proximity;
}
.testimonial-card {
  scroll-snap-align: start;
  min-width: 320px;
  max-width: 380px;
  background: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-md);
  padding: var(--space-3);
}
.testimonial-author { display: flex; align-items: center; gap: 0.75rem; margin-top: var(--space-2); }
.testimonial-author img { width: 44px; height: 44px; border-radius: 50%; object-fit: cover; }

/* FAQ */
.faq-item {
  border-top: 1px solid var(--color-line);
}
.faq-item:last-child { border-bottom: 1px solid var(--color-line); }
.faq-item summary {
  cursor: pointer;
  padding: var(--space-3) 0;
  font-weight: 600;
  font-size: 1.1rem;
  list-style: none;
  display: flex;
  justify-content: space-between;
  gap: var(--space-2);
}
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after {
  content: "+";
  font-size: 1.5rem;
  color: var(--color-accent);
  transition: transform var(--transition-fast);
  flex-shrink: 0;
}
.faq-item[open] summary::after { transform: rotate(45deg); }
.faq-item .faq-answer { padding-bottom: var(--space-3); color: var(--color-muted); max-width: 720px; }

/* Forms */
.form-grid { display: grid; grid-template-columns: 1fr 1fr; gap: var(--space-2) var(--space-3); }
.form-field { display: flex; flex-direction: column; gap: 0.4rem; margin-bottom: var(--space-2); }
.form-field.full { grid-column: 1 / -1; }
.form-field label { font-size: 0.9rem; font-weight: 600; }
.form-field input,
.form-field textarea,
.form-field select {
  font: inherit;
  padding: 0.8rem 1rem;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-sm);
  background: var(--color-surface);
  color: var(--color-ink);
  width: 100%;
}
.form-field input:focus,
.form-field textarea:focus,
.form-field select:focus {
  border-color: var(--color-accent);
}
.form-field .errorlist {
  list-style: none;
  margin: 0; padding: 0;
  color: var(--color-accent);
  font-size: 0.85rem;
}
.form-checkbox { display: flex; align-items: flex-start; gap: 0.6rem; }
.form-checkbox input { width: auto; margin-top: 0.3rem; }
.form-honeypot { position: absolute; left: -9999px; width: 1px; height: 1px; overflow: hidden; }
.form-alert {
  padding: var(--space-2) var(--space-3);
  border-radius: var(--radius-sm);
  margin-bottom: var(--space-3);
}
.form-alert.success { background: #e5f2e6; color: #235c2b; }
.form-alert.error { background: #fbe7e2; color: #8a2c14; }

/* Breadcrumbs */
.breadcrumbs {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  padding: 0;
  margin: 0 0 var(--space-3);
  font-size: 0.85rem;
  color: var(--color-muted);
}
.breadcrumbs li:not(:last-child)::after { content: "/"; margin-left: 0.4rem; }
.breadcrumbs a { color: var(--color-muted); text-decoration: none; }
.breadcrumbs a:hover { color: var(--color-accent); }

/* Tables of specs */
.spec-table { width: 100%; border-collapse: collapse; }
.spec-table th, .spec-table td { text-align: left; padding: 0.6rem 0; border-top: 1px solid var(--color-line); font-weight: 400; }
.spec-table th { width: 40%; color: var(--color-muted); font-weight: 500; }

.tag-list { list-style: none; display: flex; flex-wrap: wrap; gap: 0.5rem; padding: 0; margin: 0; }
.tag-list li {
  border: 1px solid var(--color-line);
  border-radius: 999px;
  padding: 0.3rem 0.9rem;
  font-size: 0.85rem;
}
.color-swatch { width: 14px; height: 14px; border-radius: 50%; display: inline-block; margin-right: 0.4rem; vertical-align: -1px; border: 1px solid rgba(0,0,0,0.1); }

/* Gallery */
.gallery-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: var(--space-2); }
.gallery-grid img { border-radius: var(--radius-md); aspect-ratio: 4/5; object-fit: cover; width: 100%; height: 100%; }

/* Filters */
.filter-bar { display: flex; flex-wrap: wrap; gap: var(--space-2); margin-bottom: var(--space-4); }
.filter-bar select {
  padding: 0.6rem 1rem;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-sm);
  background: var(--color-surface);
  font: inherit;
}

/* Footer */
.site-footer {
  background: var(--color-dark);
  color: var(--color-dark-ink);
  padding: var(--space-5) 0 var(--space-3);
}
.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: var(--space-4);
  padding-bottom: var(--space-4);
  border-bottom: 1px solid rgba(244,240,230,0.15);
}
.footer-grid h4 { font-size: 0.95rem; text-transform: uppercase; letter-spacing: 0.08em; color: var(--color-dark-muted); margin-bottom: var(--space-2); }
.footer-grid ul { list-style: none; padding: 0; margin: 0; display: flex; flex-direction: column; gap: 0.5rem; }
.footer-grid a { text-decoration: none; color: var(--color-dark-ink); }
.footer-grid a:hover { color: var(--color-accent); }
.footer-bottom { display: flex; justify-content: space-between; flex-wrap: wrap; gap: var(--space-2); padding-top: var(--space-3); font-size: 0.85rem; color: var(--color-dark-muted); }

/* Reveal animation */
.reveal { opacity: 1; transform: none; }
@media (prefers-reduced-motion: no-preference) {
  .reveal {
    opacity: 0;
    transform: translateY(16px);
    transition: opacity var(--transition-medium), transform var(--transition-medium);
  }
  .reveal.is-visible { opacity: 1; transform: none; }
}

/* Responsive */
@media (max-width: 1024px) {
  .split { grid-template-columns: 1fr; }
  .split .split-media { order: -1 !important; }
  .advantage-list { grid-template-columns: repeat(2, 1fr); }
  .grid-4 { grid-template-columns: repeat(2, 1fr); }
  .grid-3 { grid-template-columns: repeat(2, 1fr); }
  .grid-asymmetric { grid-template-columns: repeat(2, 1fr); }
  .grid-asymmetric .card-wide, .grid-asymmetric .card-narrow { grid-column: span 1; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 768px) {
  .main-nav ul, .main-nav .btn { display: none; }
  .nav-toggle { display: block; }
  .main-nav.is-open ul {
    display: flex;
    flex-direction: column;
    position: absolute;
    top: 100%; left: 0; right: 0;
    background: var(--color-bg);
    padding: var(--space-3);
    border-bottom: 1px solid var(--color-line);
    gap: var(--space-2);
  }
  .main-nav.is-open .btn { display: inline-flex; margin: var(--space-2) var(--space-3) 0; }
  .hero { min-height: 100vh; align-items: center; }
  .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
  .advantage-list { grid-template-columns: 1fr; }
  .form-grid { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; gap: var(--space-3); }
  .gallery-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 480px) {
  .hero-actions { flex-direction: column; align-items: flex-start; }
  .gallery-grid { grid-template-columns: 1fr; }
}