/* ============================================================
   KOGAN.EXPERT — Design tokens + component styles
   Concept: authoritative / precise / "белая ВЭД".
   Graphite-blue + terracotta accent on light paper surface.
   Display: General Sans (geometric grotesk, wide tracking).
   Body: Inter.
   ============================================================ */

/* ---------- Type scale ---------- */
:root {
  --text-xs: clamp(0.75rem, 0.7rem + 0.25vw, 0.875rem);
  --text-sm: clamp(0.875rem, 0.8rem + 0.35vw, 1rem);
  --text-base: clamp(1rem, 0.95rem + 0.25vw, 1.125rem);
  --text-lg: clamp(1.125rem, 1rem + 0.75vw, 1.5rem);
  --text-xl: clamp(1.5rem, 1.2rem + 1.25vw, 2.25rem);
  --text-2xl: clamp(2rem, 1.2rem + 2.5vw, 3.5rem);
  --text-3xl: clamp(2.5rem, 1rem + 4vw, 5rem);
  --text-hero: clamp(2.75rem, 0.5rem + 6.5vw, 7rem);

  /* ---------- Spacing (4px base) ---------- */
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.25rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  --space-16: 4rem;
  --space-20: 5rem;
  --space-24: 6rem;
  --space-32: 8rem;

  /* ---------- Radius ---------- */
  --radius-sm: 0.25rem;
  --radius-md: 0.375rem;
  --radius-lg: 0.5rem;
  --radius-xl: 0.75rem;
  --radius-full: 9999px;

  --transition-interactive: 180ms cubic-bezier(0.16, 1, 0.3, 1);
  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);

  --content-narrow: 640px;
  --content-default: 980px;
  --content-wide: 1240px;
  --content-full: 100%;

  --font-display: 'General Sans', 'Helvetica Neue', sans-serif;
  --font-body: 'Inter', 'Helvetica Neue', sans-serif;
  --font-mono: 'JetBrains Mono', 'Courier New', monospace;
}

/* ---------- Color — Light (default) ---------- */
:root,
[data-theme='light'] {
  /* Surfaces — warm paper, not stark white */
  --color-bg: #f5f3ee;
  --color-surface: #faf9f5;
  --color-surface-2: #ffffff;
  --color-surface-offset: #ece9e1;
  --color-surface-offset-2: #e2ded3;
  --color-surface-dynamic: #d9d4c7;
  --color-divider: #ddd8cc;
  --color-border: #cdc7b8;

  /* Text — graphite-blue ink */
  --color-text: #1c2430;
  --color-text-muted: #5b6472;
  --color-text-faint: #98a0aa;
  --color-text-inverse: #f5f3ee;

  /* Primary — graphite-blue */
  --color-primary: #1c2430;
  --color-primary-hover: #2b3648;
  --color-primary-active: #10151d;
  --color-primary-highlight: #dfe2e7;

  /* Accent — brown-terracotta */
  --color-accent: #b0552f;
  --color-accent-hover: #8f4325;
  --color-accent-active: #71351d;
  --color-accent-highlight: #ecd6c8;

  --color-warning: #964219;
  --color-error: #a12c2c;
  --color-success: #43642a;

  --shadow-sm: 0 1px 2px oklch(0.2 0.02 250 / 0.06);
  --shadow-md: 0 4px 16px oklch(0.2 0.02 250 / 0.08);
  --shadow-lg: 0 16px 40px oklch(0.2 0.02 250 / 0.14);
}

/* ---------- Color — Dark ---------- */
[data-theme='dark'] {
  --color-bg: #14181f;
  --color-surface: #191e26;
  --color-surface-2: #1e242d;
  --color-surface-offset: #20262f;
  --color-surface-offset-2: #262d38;
  --color-surface-dynamic: #313945;
  --color-divider: #2a313c;
  --color-border: #3a4351;

  --color-text: #e8e6de;
  --color-text-muted: #a3a9b3;
  --color-text-faint: #6b7280;
  --color-text-inverse: #14181f;

  --color-primary: #c7ccd4;
  --color-primary-hover: #e8e6de;
  --color-primary-active: #ffffff;
  --color-primary-highlight: #2b3648;

  --color-accent: #d97b4f;
  --color-accent-hover: #e8935f;
  --color-accent-active: #f0a877;
  --color-accent-highlight: #3a2a20;

  --color-warning: #d97b4f;
  --color-error: #d1685f;
  --color-success: #7ea862;

  --shadow-sm: 0 1px 2px oklch(0 0 0 / 0.3);
  --shadow-md: 0 4px 16px oklch(0 0 0 / 0.35);
  --shadow-lg: 0 16px 40px oklch(0 0 0 / 0.5);
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme]) {
    --color-bg: #14181f;
    --color-surface: #191e26;
    --color-surface-2: #1e242d;
    --color-surface-offset: #20262f;
    --color-surface-offset-2: #262d38;
    --color-surface-dynamic: #313945;
    --color-divider: #2a313c;
    --color-border: #3a4351;
    --color-text: #e8e6de;
    --color-text-muted: #a3a9b3;
    --color-text-faint: #6b7280;
    --color-text-inverse: #14181f;
    --color-primary: #c7ccd4;
    --color-primary-hover: #e8e6de;
    --color-primary-active: #ffffff;
    --color-primary-highlight: #2b3648;
    --color-accent: #d97b4f;
    --color-accent-hover: #e8935f;
    --color-accent-active: #f0a877;
    --color-accent-highlight: #3a2a20;
  }
}

/* ============================================================
   BASE
   ============================================================ */

body {
  font-family: var(--font-body);
  background-color: var(--color-bg);
  background-image:
    linear-gradient(var(--color-divider) 1px, transparent 1px),
    linear-gradient(90deg, var(--color-divider) 1px, transparent 1px);
  background-size: 100% 100%;
}

::-webkit-scrollbar { width: 10px; height: 10px; }
::-webkit-scrollbar-track { background: var(--color-bg); }
::-webkit-scrollbar-thumb { background: var(--color-border); border-radius: var(--radius-full); }

.container {
  max-width: var(--content-default);
  margin-inline: auto;
  padding-inline: var(--space-5);
}
.container--wide {
  max-width: var(--content-wide);
  margin-inline: auto;
  padding-inline: var(--space-5);
}
.container--narrow {
  max-width: var(--content-narrow);
  margin-inline: auto;
  padding-inline: var(--space-5);
}

section {
  padding-block: clamp(var(--space-16), 9vw, var(--space-32));
}
section.section--tight {
  padding-block: clamp(var(--space-10), 6vw, var(--space-16));
}

/* ---------- Headings / display type ---------- */
h1, h2, h3, .display {
  font-family: var(--font-display);
  font-weight: 600;
  letter-spacing: 0.01em;
  color: var(--color-text);
}
.eyebrow {
  font-family: var(--font-body);
  font-size: var(--text-xs);
  font-weight: 600;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--color-accent);
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
}
.eyebrow::before {
  content: '';
  width: 20px;
  height: 1px;
  background: var(--color-accent);
  display: inline-block;
}

.hero-title {
  font-size: var(--text-hero);
  letter-spacing: -0.01em;
  line-height: 1.02;
}
.section-title {
  font-size: var(--text-2xl);
  letter-spacing: -0.005em;
  line-height: 1.08;
}
.page-title {
  font-size: var(--text-xl);
  letter-spacing: 0;
}

p {
  color: var(--color-text-muted);
  max-width: 62ch;
}
.lede {
  font-size: var(--text-lg);
  color: var(--color-text);
  max-width: 46ch;
  line-height: 1.5;
}

a { color: inherit; text-decoration: none; }

/* ---------- Numbered block index — (01) (02) signature motif ---------- */
.block-index {
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  color: var(--color-accent);
  font-variant-numeric: tabular-nums;
  letter-spacing: 0.02em;
}

/* ============================================================
   HEADER / NAV
   ============================================================ */
.header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: oklch(from var(--color-bg) l c h / 0.92);
  backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--color-divider);
  transition: transform 0.3s var(--ease-out), box-shadow 0.3s var(--ease-out);
}
.header--hidden { transform: translateY(-100%); }
.header--scrolled { box-shadow: var(--shadow-sm); }

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-block: var(--space-4);
  gap: var(--space-3);
}
@media (min-width: 640px) {
  .header-inner { gap: var(--space-6); }
}

.logo {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  font-family: var(--font-display);
  font-weight: 600;
  font-size: var(--text-base);
  letter-spacing: 0.02em;
  color: var(--color-text);
  flex-shrink: 0;
}
.logo svg { width: 34px; height: 34px; color: var(--color-accent); }
.logo .logo-sub {
  display: none;
  font-family: var(--font-body);
  font-weight: 400;
  font-size: var(--text-xs);
  letter-spacing: 0.08em;
  color: var(--color-text-muted);
  text-transform: uppercase;
}
@media (min-width: 640px) {
  .logo .logo-sub { display: block; }
}

.nav-desktop {
  display: none;
  align-items: center;
  gap: var(--space-8);
}
.nav-desktop a {
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-text-muted);
  letter-spacing: 0.01em;
  padding-block: var(--space-1);
  border-bottom: 1px solid transparent;
}
.nav-desktop a:hover,
.nav-desktop a.active {
  color: var(--color-text);
  border-color: var(--color-accent);
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  flex-shrink: 0;
}
@media (min-width: 640px) {
  .nav-actions { gap: var(--space-4); }
}

.lang-switch {
  display: none;
  align-items: center;
  gap: var(--space-1);
  font-size: var(--text-xs);
  font-weight: 600;
  letter-spacing: 0.04em;
}
@media (min-width: 480px) {
  .header-inner .lang-switch { display: flex; }
}
.nav-mobile .lang-switch { display: flex; }
.lang-switch a, .lang-switch span {
  padding: var(--space-1) var(--space-2);
  color: var(--color-text-faint);
}
.lang-switch a:hover { color: var(--color-text); }
.lang-switch .active { color: var(--color-text); background: var(--color-surface-offset); border-radius: var(--radius-sm); }

.theme-toggle {
  width: 36px; height: 36px;
  display: flex; align-items: center; justify-content: center;
  border-radius: var(--radius-full);
  color: var(--color-text-muted);
  border: 1px solid var(--color-border);
}
.theme-toggle:hover { color: var(--color-text); border-color: var(--color-text-muted); }
.theme-toggle svg { width: 16px; height: 16px; }

.menu-toggle {
  display: flex;
  width: 40px; height: 40px;
  align-items: center; justify-content: center;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  color: var(--color-text);
}

@media (min-width: 900px) {
  .nav-desktop { display: flex; }
  .menu-toggle { display: none; }
}

/* Mobile nav sheet */
.nav-mobile {
  position: fixed;
  inset: 0;
  z-index: 200;
  background: var(--color-bg);
  display: flex;
  flex-direction: column;
  padding: var(--space-5);
  transform: translateX(100%);
  transition: transform 0.35s var(--ease-out);
}
.nav-mobile.is-open { transform: translateX(0); }
.nav-mobile-top { display: flex; justify-content: space-between; align-items: center; margin-bottom: var(--space-12); }
.nav-mobile a {
  font-family: var(--font-display);
  font-size: var(--text-xl);
  font-weight: 600;
  padding-block: var(--space-3);
  border-bottom: 1px solid var(--color-divider);
  color: var(--color-text);
}
.nav-mobile-footer {
  margin-top: auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-top: var(--space-6);
}

/* ============================================================
   BUTTONS
   ============================================================ */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  font-size: var(--text-sm);
  font-weight: 600;
  letter-spacing: 0.01em;
  padding: var(--space-4) var(--space-6);
  border-radius: var(--radius-sm);
  border: 1px solid transparent;
  white-space: nowrap;
}
.btn-primary {
  background: var(--color-primary);
  color: var(--color-text-inverse);
}
.btn-primary:hover { background: var(--color-primary-hover); }
.btn-accent {
  background: var(--color-accent);
  color: #fdf8f4;
}
.btn-accent:hover { background: var(--color-accent-hover); }
.btn-outline {
  border-color: var(--color-border);
  color: var(--color-text);
}
.btn-outline:hover { border-color: var(--color-text); background: var(--color-surface-offset); }
.btn svg { width: 16px; height: 16px; transition: transform var(--transition-interactive); }
.btn:hover svg { transform: translateX(3px); }

/* ============================================================
   HERO
   ============================================================ */
.hero {
  padding-top: clamp(var(--space-20), 12vw, var(--space-32));
  padding-bottom: clamp(var(--space-16), 8vw, var(--space-24));
  position: relative;
  overflow: hidden;
}
.hero-grid {
  display: grid;
  gap: var(--space-10);
}
.hero-meta {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-6);
  margin-top: var(--space-10);
  padding-top: var(--space-8);
  border-top: 1px solid var(--color-divider);
}
.hero-meta-item .num {
  font-family: var(--font-display);
  font-size: var(--text-xl);
  color: var(--color-text);
  display: block;
}
.hero-meta-item .label {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

/* ============================================================
   NUMBERED SECTIONS (01)(02) motif
   ============================================================ */
.section-head {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-end;
  justify-content: space-between;
  gap: var(--space-6);
  margin-bottom: clamp(var(--space-10), 5vw, var(--space-16));
}
.section-head-left { max-width: 640px; }
.section-head .block-index {
  font-size: var(--text-lg);
}

/* ============================================================
   CARDS
   ============================================================ */
.card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-8);
  transition: box-shadow var(--transition-interactive), border-color var(--transition-interactive), transform var(--transition-interactive);
}
.card:hover {
  box-shadow: var(--shadow-md);
  border-color: var(--color-text-faint);
}
.card-link { display: block; height: 100%; }
.card .block-index { display: block; margin-bottom: var(--space-6); }
.card h3 { font-size: var(--text-lg); margin-bottom: var(--space-3); }
.card p { font-size: var(--text-sm); margin-bottom: 0; }

.stat-card {
  border-top: 2px solid var(--color-accent);
  padding-top: var(--space-5);
}
.stat-card .num {
  font-family: var(--font-display);
  font-size: var(--text-2xl);
  color: var(--color-text);
  line-height: 1;
}
.stat-card .label {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  margin-top: var(--space-2);
}

/* ============================================================
   GRID LAYOUTS
   ============================================================ */
.grid-2 { display: grid; gap: var(--space-8); grid-template-columns: 1fr; }
.grid-3 { display: grid; gap: var(--space-6); grid-template-columns: 1fr; }
.grid-4 { display: grid; gap: var(--space-6); grid-template-columns: repeat(2, 1fr); }
@media (min-width: 700px) {
  .grid-2 { grid-template-columns: repeat(2, 1fr); }
  .grid-3 { grid-template-columns: repeat(3, 1fr); }
}
@media (min-width: 900px) {
  .grid-4 { grid-template-columns: repeat(4, 1fr); }
}

/* ============================================================
   CTA BAND
   ============================================================ */
.cta-band {
  background: var(--color-primary);
  color: var(--color-text-inverse);
  border-radius: var(--radius-xl);
  padding: clamp(var(--space-10), 6vw, var(--space-16));
  position: relative;
  overflow: hidden;
}
.cta-band h2, .cta-band .eyebrow { color: var(--color-text-inverse); }
.cta-band .eyebrow { color: #e8935f; }
.cta-band .eyebrow::before { background: #e8935f; }
.cta-band p { color: oklch(from var(--color-text-inverse) l c h / 0.72); }

/* ============================================================
   CROSS-LINK CARDS (realmultd / hubgt)
   ============================================================ */
.ecosystem-card {
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-8);
  background: var(--color-surface);
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
}
.ecosystem-card .site-tag {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-accent);
  letter-spacing: 0.04em;
}

/* ============================================================
   FOOTER
   ============================================================ */
.footer {
  border-top: 1px solid var(--color-divider);
  padding-block: var(--space-16) var(--space-10);
}
.footer-grid {
  display: grid;
  gap: var(--space-10);
  grid-template-columns: 1fr;
  margin-bottom: var(--space-12);
}
@media (min-width: 700px) {
  .footer-grid { grid-template-columns: 1.4fr 1fr 1fr 1fr; }
}
.footer-col h4 {
  font-size: var(--text-xs);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--color-text-muted);
  margin-bottom: var(--space-4);
}
.footer-col a, .footer-col p {
  display: block;
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  margin-bottom: var(--space-3);
}
.footer-col a:hover { color: var(--color-accent); }
.footer-bottom {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: var(--space-4);
  padding-top: var(--space-8);
  border-top: 1px solid var(--color-divider);
  font-size: var(--text-xs);
  color: var(--color-text-faint);
}

/* ============================================================
   BREADCRUMB
   ============================================================ */
.breadcrumb {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-size: var(--text-xs);
  color: var(--color-text-faint);
  padding-top: var(--space-6);
}
.breadcrumb a:hover { color: var(--color-accent); }

/* ============================================================
   TAGS / PILLS
   ============================================================ */
.pill {
  display: inline-flex;
  align-items: center;
  font-size: var(--text-xs);
  font-weight: 600;
  padding: var(--space-1) var(--space-3);
  border-radius: var(--radius-full);
  background: var(--color-surface-offset);
  color: var(--color-text-muted);
  letter-spacing: 0.02em;
}

/* ============================================================
   BLOG
   ============================================================ */
.article-card {
  border-bottom: 1px solid var(--color-divider);
  padding-block: var(--space-8);
  display: grid;
  gap: var(--space-4);
  grid-template-columns: 1fr;
}
@media (min-width: 700px) {
  .article-card { grid-template-columns: 120px 1fr; align-items: baseline; }
}
.article-card .date {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-text-faint);
}
.article-card h3 { font-size: var(--text-lg); margin-bottom: var(--space-2); }

.prose { max-width: 68ch; }
.prose h2 { font-size: var(--text-xl); margin-top: var(--space-12); margin-bottom: var(--space-4); }
.prose h3 { font-size: var(--text-lg); margin-top: var(--space-8); margin-bottom: var(--space-3); }
.prose p { max-width: none; margin-bottom: var(--space-5); font-size: var(--text-base); color: var(--color-text); }
.prose ul, .prose ol { margin-bottom: var(--space-5); padding-left: var(--space-6); color: var(--color-text); }
.prose li { margin-bottom: var(--space-2); color: var(--color-text); max-width: none; }
.prose blockquote {
  border-left: 3px solid var(--color-accent);
  padding-left: var(--space-6);
  font-family: var(--font-display);
  font-size: var(--text-lg);
  font-weight: 500;
  margin-block: var(--space-8);
  color: var(--color-text);
}

/* ============================================================
   FORMS
   ============================================================ */
.form-field { margin-bottom: var(--space-5); }
.form-field label {
  display: block;
  font-size: var(--text-xs);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-text-muted);
  margin-bottom: var(--space-2);
}
.form-field input,
.form-field textarea {
  width: 100%;
  padding: var(--space-4);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  font-size: var(--text-base);
}
.form-field input:focus,
.form-field textarea:focus {
  outline: none;
  border-color: var(--color-accent);
  box-shadow: 0 0 0 3px oklch(from var(--color-accent) l c h / 0.15);
}
.form-field textarea { min-height: 140px; resize: vertical; }

/* ============================================================
   TIMELINE (expertise/education)
   ============================================================ */
.timeline-item {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-3);
  padding-block: var(--space-8);
  border-bottom: 1px solid var(--color-divider);
}
@media (min-width: 700px) {
  .timeline-item { grid-template-columns: 160px 1fr; gap: var(--space-8); }
}
.timeline-item .years {
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  color: var(--color-accent);
}
.timeline-item h3 { font-size: var(--text-lg); margin-bottom: var(--space-2); }

/* ============================================================
   SCROLL REVEAL
   ============================================================ */
.reveal {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity 0.7s var(--ease-out), transform 0.7s var(--ease-out);
}
.reveal.is-visible {
  opacity: 1;
  transform: translateY(0);
}

/* ============================================================
   UTILITIES
   ============================================================ */
.mt-0 { margin-top: 0 !important; }
.text-center { text-align: center; }
.flex { display: flex; }
.flex-wrap { flex-wrap: wrap; }
.items-center { align-items: center; }
.gap-4 { gap: var(--space-4); }
.gap-6 { gap: var(--space-6); }
.full-bleed-img {
  width: 100%;
  aspect-ratio: 16/7;
  object-fit: cover;
  border-radius: var(--radius-lg);
}