/* ============================================================
   ИКЦ «Северная Корона» — styles.css
   Design spec: design-spec.md | Brand: brand-requirements.md
   Mobile-first, CSS Grid + Flexbox, no build tools required
   ============================================================ */

/* ── CSS Variables ── */
:root {
  /* Primary colors */
  --color-primary-dark:  #0A1628;
  --color-primary-navy:  #0E2A4F;
  --color-primary-mid:   #1E3A5F;

  /* Accent colors */
  --color-accent:        #1B6FE8;
  --color-accent-hover:  #2B7FFF;
  --color-accent-light:  #E8F1FF;

  /* Neutral */
  --color-bg-light:      #F7F8FA;
  --color-bg-white:      #FFFFFF;
  --color-text-primary:  #1A202C;
  --color-text-secondary:#4A5568;
  --color-text-muted:    #718096;
  --color-border:        #E2E8F0;

  /* Signal */
  --color-success:       #38A169;
  --color-warning:       #D69E2E;
  --color-error:         #E53E3E;

  /* Typography */
  --font-primary:   'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-body:      'Source Sans 3', 'Georgia', serif;
  --font-mono:      'JetBrains Mono', 'Menlo', monospace;

  /* Spacing */
  --section-padding: 96px;
  --section-padding-sm: 64px;
  --container-max:   1280px;
  --container-pad:   24px;

  /* Radius */
  --radius-sm:  8px;
  --radius-md:  12px;
  --radius-lg:  16px;

  /* Transitions */
  --transition-fast:   0.15s ease;
  --transition-base:   0.2s ease;
  --transition-slow:   0.28s cubic-bezier(0.4, 0, 0.2, 1);
}

/* ── Reset & Base ── */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

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

body {
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.6;
  color: var(--color-text-primary);
  background-color: var(--color-bg-white);
  overflow-x: hidden;
}

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

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

ul, ol { list-style: none; }

button {
  font-family: inherit;
  background: none;
  border: none;
  cursor: pointer;
}

address { font-style: normal; }

/* ── Container ── */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--container-pad);
}

/* ── Visually Hidden ── */
.sr-only {
  position: absolute;
  width: 1px; height: 1px;
  padding: 0; margin: -1px;
  overflow: hidden;
  clip: rect(0,0,0,0);
  white-space: nowrap;
  border: 0;
}

/* ============================================================
   BUTTONS
   ============================================================ */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 28px;
  border-radius: var(--radius-sm);
  font-family: var(--font-primary);
  font-size: 15px;
  font-weight: 600;
  letter-spacing: 0.01em;
  line-height: 1;
  cursor: pointer;
  transition: background var(--transition-base),
              transform var(--transition-fast),
              box-shadow var(--transition-base),
              border-color var(--transition-base),
              color var(--transition-base);
  white-space: nowrap;
  text-decoration: none;
}

.btn-lg {
  padding: 14px 32px;
  font-size: 16px;
}

.btn-primary {
  background: var(--color-accent);
  color: #fff;
  border: none;
  box-shadow: 0 2px 8px rgba(27, 111, 232, 0.35);
}

.btn-primary:hover {
  background: var(--color-accent-hover);
  transform: translateY(-1px);
  box-shadow: 0 4px 16px rgba(27, 111, 232, 0.5);
}

.btn-primary:active {
  transform: translateY(0);
  box-shadow: 0 1px 4px rgba(27, 111, 232, 0.3);
}

.btn-secondary {
  background: transparent;
  color: var(--color-accent);
  border: 1.5px solid var(--color-accent);
}

.btn-secondary:hover {
  background: var(--color-accent-light);
  border-color: var(--color-accent-hover);
  color: var(--color-accent-hover);
}

.btn-ghost-dark {
  background: rgba(255, 255, 255, 0.1);
  color: #fff;
  border: 1.5px solid rgba(255, 255, 255, 0.3);
  backdrop-filter: blur(8px);
}

.btn-ghost-dark:hover {
  background: rgba(255, 255, 255, 0.18);
  border-color: rgba(255, 255, 255, 0.55);
}

/* Submit button loading state */
.btn-submit {
  position: relative;
  min-width: 260px;
}

.btn-submit__spinner {
  display: none;
  width: 18px; height: 18px;
  border: 2px solid rgba(255,255,255,0.3);
  border-top-color: #fff;
  border-radius: 50%;
  animation: spin 0.7s linear infinite;
}

.btn-submit.loading .btn-submit__text { opacity: 0; }
.btn-submit.loading .btn-submit__spinner { display: block; }

@keyframes spin {
  to { transform: rotate(360deg); }
}

/* ============================================================
   BADGES
   ============================================================ */

.badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-family: var(--font-primary);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.02em;
  text-transform: uppercase;
  border-radius: 100px;
  padding: 5px 12px;
}

.badge-accent {
  background: rgba(27, 111, 232, 0.12);
  border: 1px solid rgba(27, 111, 232, 0.35);
  color: #93C5FD;
}

.badge-section {
  background: var(--color-accent-light);
  border: 1px solid rgba(27, 111, 232, 0.2);
  color: var(--color-accent);
}

/* ============================================================
   SECTION HEADERS
   ============================================================ */

.section-header {
  text-align: center;
  margin-bottom: 56px;
}

.section-header--light .section-title,
.section-header--light .section-lead {
  color: #fff;
}

.section-title {
  font-family: var(--font-primary);
  font-size: clamp(1.75rem, 4vw, 2rem);
  font-weight: 600;
  line-height: 1.25;
  color: var(--color-text-primary);
  margin-top: 12px;
}

.section-title--light { color: #fff; }

.section-lead {
  font-size: 1.0625rem;
  line-height: 1.7;
  color: var(--color-text-secondary);
  max-width: 680px;
  margin: 16px auto 0;
}

.section-lead--light { color: rgba(255,255,255,0.75); }

/* ============================================================
   FORM INPUTS
   ============================================================ */

.input-label {
  display: block;
  font-family: var(--font-primary);
  font-size: 13px;
  font-weight: 500;
  color: var(--color-text-secondary);
  margin-bottom: 6px;
}

.input-field {
  width: 100%;
  padding: 12px 16px;
  font-family: var(--font-primary);
  font-size: 15px;
  color: var(--color-text-primary);
  background: var(--color-bg-white);
  border: 1.5px solid var(--color-border);
  border-radius: var(--radius-sm);
  outline: none;
  transition: border-color var(--transition-base), box-shadow var(--transition-base);
}

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

.input-field:focus {
  border-color: var(--color-accent);
  box-shadow: 0 0 0 3px rgba(27, 111, 232, 0.12);
}

.input-field.error {
  border-color: var(--color-error);
  box-shadow: 0 0 0 3px rgba(229, 62, 62, 0.1);
}

.input-field--textarea {
  resize: vertical;
  min-height: 88px;
}

/* ============================================================
   FILTER TAGS
   ============================================================ */

.filter-tag {
  padding: 6px 18px;
  border-radius: 100px;
  font-family: var(--font-primary);
  font-size: 14px;
  font-weight: 500;
  cursor: pointer;
  border: 1.5px solid var(--color-border);
  background: var(--color-bg-white);
  color: var(--color-text-secondary);
  transition: all var(--transition-fast);
}

.filter-tag:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
}

.filter-tag.active {
  background: var(--color-accent);
  border-color: var(--color-accent);
  color: #fff;
}

/* ============================================================
   HEADER
   ============================================================ */

.header {
  position: sticky;
  top: 0;
  z-index: 1000;
  height: 72px;
  background: var(--color-primary-navy);
  transition: box-shadow var(--transition-base);
}

.header.scrolled {
  box-shadow: 0 2px 20px rgba(0, 0, 0, 0.3);
}

.header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
  gap: 24px;
}

/* Logo */
.header__logo {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-shrink: 0;
}

.header__logo-text {
  font-family: var(--font-primary);
  font-size: 16px;
  font-weight: 600;
  color: #fff;
  white-space: nowrap;
}

/* Desktop Nav */
.header__nav { display: none; }

.header__nav-list {
  display: flex;
  align-items: center;
  gap: 4px;
}

.header__nav-list > li { position: relative; }

.header__nav-link {
  display: flex;
  align-items: center;
  gap: 4px;
  padding: 8px 12px;
  font-family: var(--font-primary);
  font-size: 15px;
  font-weight: 500;
  color: rgba(255,255,255,0.85);
  border-radius: 6px;
  transition: color var(--transition-base), background var(--transition-base);
}

.header__nav-link:hover {
  color: #fff;
  background: rgba(255,255,255,0.08);
}

/* Dropdown */
.dropdown {
  position: absolute;
  top: calc(100% + 8px);
  left: 0;
  min-width: 220px;
  background: var(--color-bg-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  box-shadow: 0 8px 32px rgba(0,0,0,0.12);
  padding: 8px 0;
  opacity: 0;
  visibility: hidden;
  transform: translateY(-8px);
  transition: opacity var(--transition-base), visibility var(--transition-base), transform var(--transition-base);
  z-index: 100;
}

.has-dropdown:hover .dropdown,
.has-dropdown:focus-within .dropdown {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.dropdown__link {
  display: block;
  padding: 10px 16px;
  font-family: var(--font-primary);
  font-size: 14px;
  color: var(--color-text-secondary);
  transition: color var(--transition-fast), background var(--transition-fast);
}

.dropdown__link:hover {
  color: var(--color-accent);
  background: var(--color-accent-light);
}

/* Header Actions */
.header__actions {
  display: flex;
  align-items: center;
  gap: 12px;
}

/* Burger Button */
.burger {
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 40px;
  height: 40px;
  padding: 8px;
  border-radius: 6px;
  transition: background var(--transition-fast);
}

.burger span {
  display: block;
  width: 100%;
  height: 2px;
  background: #fff;
  border-radius: 2px;
  transition: transform var(--transition-slow), opacity var(--transition-fast);
}

.burger:hover { background: rgba(255,255,255,0.1); }

.burger.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.burger.open span:nth-child(2) { opacity: 0; }
.burger.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ============================================================
   MOBILE NAV
   ============================================================ */

.mobile-nav-overlay {
  position: fixed;
  inset: 0;
  background: rgba(10, 22, 40, 0.7);
  backdrop-filter: blur(4px);
  z-index: 1001;
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--transition-slow), visibility var(--transition-slow);
}

.mobile-nav-overlay.active {
  opacity: 1;
  visibility: visible;
}

.mobile-nav {
  position: fixed;
  top: 0;
  right: 0;
  bottom: 0;
  width: min(320px, 85vw);
  background: var(--color-primary-navy);
  z-index: 1002;
  padding: 24px;
  transform: translateX(100%);
  transition: transform var(--transition-slow);
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.mobile-nav.open {
  transform: translateX(0);
}

.mobile-nav__close {
  align-self: flex-end;
  color: rgba(255,255,255,0.7);
  padding: 4px;
  border-radius: 6px;
  transition: color var(--transition-fast), background var(--transition-fast);
}

.mobile-nav__close:hover {
  color: #fff;
  background: rgba(255,255,255,0.1);
}

.mobile-nav__list { display: flex; flex-direction: column; gap: 4px; }

.mobile-nav__link {
  display: block;
  padding: 12px 16px;
  font-family: var(--font-primary);
  font-size: 16px;
  font-weight: 500;
  color: rgba(255,255,255,0.85);
  border-radius: var(--radius-sm);
  transition: color var(--transition-fast), background var(--transition-fast);
}

.mobile-nav__link:hover {
  color: #fff;
  background: rgba(255,255,255,0.08);
}

.mobile-nav__cta { align-self: flex-start; margin-top: auto; }

/* ============================================================
   HERO
   ============================================================ */

.hero {
  position: relative;
  background: var(--color-primary-dark);
  overflow: hidden;
  padding-top: 80px;
  padding-bottom: 0;
}

.hero__bg-pattern {
  position: absolute;
  inset: 0;
  pointer-events: none;
  opacity: 0.6;
}

.hero__inner {
  position: relative;
  z-index: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 56px;
  padding-bottom: 80px;
}

.hero__content {
  display: flex;
  flex-direction: column;
  gap: 20px;
  text-align: center;
  max-width: 640px;
}

.hero__title {
  font-family: var(--font-primary);
  font-size: clamp(2.25rem, 8vw, 3.5rem);
  font-weight: 700;
  line-height: 1.1;
  color: #fff;
}

.hero__lead {
  font-size: 1.125rem;
  line-height: 1.7;
  color: rgba(255, 255, 255, 0.75);
}

.hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  justify-content: center;
}

/* Hero Illustration */
.hero__illustration {
  width: 100%;
  max-width: 400px;
  flex-shrink: 0;
}

.hero__orbit-svg { width: 100%; height: auto; }

/* Orbit node pulse animation */
.orbit-node {
  transform-origin: center;
  animation: nodePulse 3s ease-in-out infinite;
}

.orbit-node--1 { animation-delay: 0s; }
.orbit-node--2 { animation-delay: 0.6s; }
.orbit-node--3 { animation-delay: 1.2s; }
.orbit-node--4 { animation-delay: 1.8s; }
.orbit-node--5 { animation-delay: 2.4s; }

@keyframes nodePulse {
  0%, 100% { opacity: 0.7; transform: scale(1); }
  50% { opacity: 1; transform: scale(1.25); }
}

.pulse-ring {
  animation: pulseRing 3s ease-in-out infinite;
  transform-origin: center;
}

@keyframes pulseRing {
  0%, 100% { opacity: 0.15; transform: scale(1); }
  50% { opacity: 0.35; transform: scale(1.08); }
}

/* Client logos bar */
.hero__clients {
  border-top: 1px solid rgba(255,255,255,0.08);
  background: rgba(0,0,0,0.15);
  padding: 24px 0;
  width: 100%;
}

.hero__clients-label {
  font-family: var(--font-primary);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: rgba(255,255,255,0.4);
  text-align: center;
  margin-bottom: 16px;
}

.hero__clients-logos {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  align-items: center;
  gap: 24px 40px;
}

.client-logo {
  font-family: var(--font-primary);
  font-size: 14px;
  font-weight: 600;
  letter-spacing: 0.04em;
  color: rgba(255,255,255,0.4);
  text-transform: uppercase;
  transition: color var(--transition-base);
}

.client-logo:hover { color: rgba(255,255,255,0.7); }

/* ============================================================
   METRICS
   ============================================================ */

.metrics {
  background: var(--color-bg-light);
  padding: 56px 0;
}

.metrics__grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 0;
}

.metrics__item {
  text-align: center;
  padding: 28px 24px;
  border-right: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
}

.metrics__item:nth-child(2n) { border-right: none; }
.metrics__item:nth-child(3),
.metrics__item:nth-child(4) { border-bottom: none; }

.metrics__number {
  display: block;
  font-family: var(--font-primary);
  font-size: clamp(2rem, 6vw, 2.5rem);
  font-weight: 700;
  line-height: 1;
  color: var(--color-primary-navy);
}

.metrics__suffix {
  font-family: var(--font-primary);
  font-size: clamp(1.5rem, 4vw, 2rem);
  font-weight: 700;
  color: var(--color-accent);
}

.metrics__label {
  font-size: 0.875rem;
  color: var(--color-text-secondary);
  margin-top: 8px;
  line-height: 1.4;
}

/* ============================================================
   PRODUCTS (САПР Альбатрос)
   ============================================================ */

.products {
  background: var(--color-bg-white);
  padding: var(--section-padding) 0;
}

.modules-scroll {
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: thin;
  scrollbar-color: var(--color-border) transparent;
  margin: 0 calc(-1 * var(--container-pad));
  padding: 0 var(--container-pad) 8px;
}

.modules-scroll::-webkit-scrollbar { height: 4px; }
.modules-scroll::-webkit-scrollbar-track { background: transparent; }
.modules-scroll::-webkit-scrollbar-thumb {
  background: var(--color-border);
  border-radius: 2px;
}

.modules-grid {
  display: flex;
  gap: 16px;
  width: max-content;
}

.card-module {
  background: var(--color-bg-light);
  border-radius: 10px;
  padding: 20px;
  border: 1px solid var(--color-border);
  display: flex;
  flex-direction: column;
  gap: 8px;
  width: 200px;
  transition: border-color var(--transition-base), background var(--transition-base);
  flex-shrink: 0;
}

.card-module:hover {
  border-color: var(--color-accent);
  background: #EEF5FF;
}

.card-module__icon {
  width: 40px;
  height: 40px;
  color: var(--color-accent);
}

.card-module__icon svg {
  width: 100%;
  height: 100%;
}

.card-module__title {
  font-family: var(--font-primary);
  font-size: 14px;
  font-weight: 600;
  color: var(--color-text-primary);
  line-height: 1.3;
}

.card-module__desc {
  font-size: 13px;
  color: var(--color-text-secondary);
  line-height: 1.5;
}

.products__cta {
  text-align: center;
  margin-top: 40px;
}

/* ============================================================
   SERVICES
   ============================================================ */

.services {
  background: var(--color-primary-navy);
  padding: var(--section-padding) 0;
}

.services__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 20px;
}

.card-service-dark {
  background: rgba(255, 255, 255, 0.05);
  border-radius: var(--radius-md);
  padding: 32px 28px;
  border: 1px solid rgba(255, 255, 255, 0.1);
  transition: background var(--transition-base), border-color var(--transition-base);
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.card-service-dark:hover {
  background: rgba(27, 111, 232, 0.12);
  border-color: rgba(27, 111, 232, 0.4);
}

.card-service-dark__icon {
  width: 48px;
  height: 48px;
  color: #93C5FD;
}

.card-service-dark__icon svg {
  width: 100%;
  height: 100%;
}

.card-service-dark__title {
  font-family: var(--font-primary);
  font-size: 1.125rem;
  font-weight: 600;
  color: #fff;
  line-height: 1.3;
}

.card-service-dark__desc {
  font-size: 0.9375rem;
  color: rgba(255,255,255,0.7);
  line-height: 1.6;
}

.card-service-dark__tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.card-service-dark__tags li {
  font-family: var(--font-primary);
  font-size: 12px;
  font-weight: 500;
  padding: 3px 10px;
  border-radius: 100px;
  background: rgba(27, 111, 232, 0.15);
  border: 1px solid rgba(27, 111, 232, 0.3);
  color: #93C5FD;
}

.card-service-dark__link {
  font-family: var(--font-primary);
  font-size: 14px;
  font-weight: 600;
  color: var(--color-accent-hover);
  margin-top: auto;
  transition: color var(--transition-fast);
}

.card-service-dark__link:hover { color: #fff; }

/* ============================================================
   ADVANTAGES
   ============================================================ */

.advantages {
  background: var(--color-bg-light);
  padding: var(--section-padding) 0;
}

.advantages__inner {
  display: grid;
  grid-template-columns: 1fr;
  gap: 48px;
}

/* Achievements list */
.achievements-list {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.achievements-list__item {
  display: flex;
  align-items: flex-start;
  gap: 14px;
  font-size: 1rem;
  color: var(--color-text-primary);
  line-height: 1.5;
}

.achievements-list__check {
  flex-shrink: 0;
  width: 24px;
  height: 24px;
  border-radius: 50%;
  background: var(--color-accent-light);
  border: 1.5px solid var(--color-accent);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-accent);
  margin-top: 1px;
}

.achievements-list__check svg {
  width: 12px;
  height: 12px;
}

/* Feature Cards */
.advantages__features {
  display: grid;
  grid-template-columns: 1fr;
  gap: 16px;
}

.card-feature {
  background: var(--color-bg-white);
  border-radius: var(--radius-md);
  padding: 28px;
  border: 1px solid var(--color-border);
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.08);
  transition: box-shadow var(--transition-base), transform var(--transition-base);
}

.card-feature:hover {
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.12);
  transform: translateY(-2px);
}

.card-feature__icon {
  width: 32px;
  height: 32px;
  color: var(--color-accent);
  margin-bottom: 14px;
}

.card-feature__icon svg { width: 100%; height: 100%; }

.card-feature__title {
  font-family: var(--font-primary);
  font-size: 1rem;
  font-weight: 600;
  color: var(--color-text-primary);
  margin-bottom: 8px;
}

.card-feature__desc {
  font-size: 0.9375rem;
  color: var(--color-text-secondary);
  line-height: 1.6;
}

/* ============================================================
   CASES / PROJECTS
   ============================================================ */

.cases {
  background: var(--color-bg-white);
  padding: var(--section-padding) 0;
}

.cases__filters {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  justify-content: center;
  margin-bottom: 40px;
}

.cases__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 24px;
}

.card-case {
  background: var(--color-bg-white);
  border-radius: var(--radius-md);
  overflow: hidden;
  border: 1px solid var(--color-border);
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.06);
  transition: transform 0.25s ease, box-shadow 0.25s ease;
}

.card-case:hover {
  transform: translateY(-4px);
  box-shadow: 0 12px 32px rgba(0, 0, 0, 0.14);
}

.card-case--hidden { display: none; }

.card-case__image {
  aspect-ratio: 16 / 9;
  overflow: hidden;
  background: var(--color-accent-light);
}

.card-case__image svg { width: 100%; height: 100%; }

.card-case__body { padding: 20px 24px; }

.card-case__tag {
  font-family: var(--font-primary);
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--color-accent);
  margin-bottom: 8px;
}

.card-case__title {
  font-family: var(--font-primary);
  font-size: 1rem;
  font-weight: 600;
  color: var(--color-text-primary);
  margin-bottom: 10px;
  line-height: 1.3;
}

.card-case__desc {
  font-size: 0.9375rem;
  color: var(--color-text-secondary);
  line-height: 1.6;
  margin-bottom: 16px;
}

.card-case__link {
  font-family: var(--font-primary);
  font-size: 14px;
  font-weight: 600;
  color: var(--color-accent);
  transition: color var(--transition-fast);
}

.card-case__link:hover { color: var(--color-accent-hover); }

/* ============================================================
   ABOUT
   ============================================================ */

.about {
  background: var(--color-primary-dark);
  padding: var(--section-padding) 0;
  position: relative;
  overflow: hidden;
}

.about::before {
  content: '';
  position: absolute;
  top: -100px;
  right: -100px;
  width: 500px;
  height: 500px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(27,111,232,0.05) 0%, transparent 70%);
  pointer-events: none;
}

.about__inner {
  display: grid;
  grid-template-columns: 1fr;
  gap: 48px;
}

.about__content {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.about__title {
  font-family: var(--font-primary);
  font-size: clamp(1.75rem, 5vw, 2.5rem);
  font-weight: 700;
  line-height: 1.2;
  color: #fff;
}

.about__text {
  font-size: 1rem;
  color: rgba(255,255,255,0.75);
  line-height: 1.7;
}

.about__contacts {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.about__contact-item {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  color: rgba(255,255,255,0.7);
  font-size: 0.9375rem;
}

.about__contact-item svg {
  width: 18px;
  height: 18px;
  flex-shrink: 0;
  color: #93C5FD;
  margin-top: 2px;
}

.about__link {
  color: rgba(255,255,255,0.7);
  transition: color var(--transition-fast);
  text-decoration: underline;
  text-underline-offset: 2px;
}

.about__link:hover { color: #fff; }

.about__visual-card {
  border-radius: var(--radius-lg);
  overflow: hidden;
  border: 1px solid rgba(255,255,255,0.08);
  background: rgba(27,111,232,0.04);
}

.about__visual-card svg { width: 100%; height: auto; }

/* ============================================================
   COURSES
   ============================================================ */

.courses {
  background: var(--color-bg-light);
  padding: var(--section-padding) 0;
}

.courses__card {
  background: var(--color-bg-white);
  border-radius: var(--radius-lg);
  border: 1px solid var(--color-border);
  box-shadow: 0 2px 12px rgba(0,0,0,0.06);
  overflow: hidden;
}

.courses__title-block {
  padding: 40px 32px 32px;
  border-bottom: 1px solid var(--color-border);
}

.courses__course-title {
  font-family: var(--font-primary);
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--color-text-primary);
  margin-bottom: 10px;
}

.courses__course-desc {
  font-size: 0.9375rem;
  color: var(--color-text-secondary);
  line-height: 1.6;
}

.courses__formats {
  display: grid;
  grid-template-columns: 1fr;
}

.courses__format-card {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 16px;
  padding: 28px 32px;
  border-bottom: 1px solid var(--color-border);
  transition: background var(--transition-base);
}

.courses__format-card:last-child { border-bottom: none; }

.courses__format-card:hover { background: var(--color-bg-light); }

.courses__format-icon {
  width: 32px;
  height: 32px;
  color: var(--color-accent);
}

.courses__format-icon svg { width: 100%; height: 100%; }

.courses__format-info {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.courses__format-label {
  font-family: var(--font-primary);
  font-size: 1rem;
  font-weight: 600;
  color: var(--color-text-primary);
}

.courses__format-duration {
  font-family: var(--font-mono);
  font-size: 0.875rem;
  color: var(--color-accent);
}

.courses__format-location {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 0.875rem;
  color: var(--color-text-muted);
}

.courses__format-location svg {
  width: 14px;
  height: 14px;
  color: var(--color-text-muted);
  flex-shrink: 0;
}

/* ============================================================
   CTA SECTION
   ============================================================ */

.cta-section {
  background: linear-gradient(135deg, var(--color-primary-navy) 0%, var(--color-accent) 100%);
  padding: var(--section-padding) 0;
}

.cta-section__inner {
  display: flex;
  flex-direction: column;
  gap: 48px;
  align-items: center;
}

.cta-section__header {
  text-align: center;
  max-width: 560px;
}

.cta-section__title {
  font-family: var(--font-primary);
  font-size: clamp(1.75rem, 5vw, 2.25rem);
  font-weight: 700;
  color: #fff;
  margin-bottom: 12px;
}

.cta-section__desc {
  font-size: 1.0625rem;
  color: rgba(255,255,255,0.8);
  line-height: 1.6;
}

.cta-form {
  background: var(--color-bg-white);
  border-radius: var(--radius-lg);
  padding: 40px 32px;
  box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
  width: 100%;
  max-width: 680px;
}

.cta-form__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 20px;
  margin-bottom: 24px;
}

.cta-form__field--wide { grid-column: 1 / -1; }

.cta-form__submit {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
}

.cta-form__privacy {
  font-size: 12px;
  color: var(--color-text-muted);
  text-align: center;
  line-height: 1.5;
}

.cta-form__privacy-link {
  color: var(--color-accent);
  text-decoration: underline;
  text-underline-offset: 2px;
}

.cta-form__success {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 16px;
  text-align: center;
  padding: 32px 0 8px;
  color: var(--color-success);
}

.cta-form__success[hidden] { display: none; }

.cta-form__success svg {
  width: 48px;
  height: 48px;
  stroke: var(--color-success);
}

.cta-form__success p {
  font-family: var(--font-primary);
  font-size: 1rem;
  color: var(--color-text-primary);
}

/* ============================================================
   FOOTER
   ============================================================ */

.footer {
  background: var(--color-primary-dark);
  padding: 64px 0 0;
}

.footer__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 40px;
  padding-bottom: 48px;
}

.footer__brand { display: flex; flex-direction: column; gap: 12px; }

.footer__logo {
  display: flex;
  align-items: center;
  gap: 10px;
}

.footer__logo span {
  font-family: var(--font-primary);
  font-size: 16px;
  font-weight: 600;
  color: #fff;
}

.footer__tagline {
  font-size: 0.875rem;
  color: rgba(255,255,255,0.5);
  line-height: 1.5;
  max-width: 220px;
}

.footer__nav-title {
  font-family: var(--font-primary);
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: rgba(255,255,255,0.45);
  margin-bottom: 16px;
}

.footer__nav-list { display: flex; flex-direction: column; gap: 10px; }

.footer__nav-link {
  font-size: 0.9375rem;
  color: rgba(255, 255, 255, 0.65);
  transition: color var(--transition-fast);
}

.footer__nav-link:hover { color: #fff; }

.footer__contact-list { display: flex; flex-direction: column; gap: 10px; }

.footer__contact-link {
  font-size: 0.9375rem;
  color: rgba(255, 255, 255, 0.65);
  transition: color var(--transition-fast);
}

.footer__contact-link:hover { color: #fff; }

.footer__address {
  font-size: 0.875rem;
  color: rgba(255,255,255,0.45);
  line-height: 1.5;
}

.footer__bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  padding: 24px 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  text-align: center;
}

.footer__copyright {
  font-size: 0.875rem;
  color: rgba(255,255,255,0.4);
}

.footer__policy {
  font-size: 0.875rem;
  color: rgba(255,255,255,0.45);
  text-decoration: underline;
  text-underline-offset: 2px;
  transition: color var(--transition-fast);
}

.footer__policy:hover { color: rgba(255,255,255,0.75); }

/* ============================================================
   SCROLL REVEAL ANIMATION
   ============================================================ */

.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.5s ease, transform 0.5s ease;
}

.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ============================================================
   RESPONSIVE — Tablet (768px+)
   ============================================================ */

@media (min-width: 768px) {

  :root {
    --container-pad: 40px;
  }

  /* Metrics */
  .metrics__grid {
    grid-template-columns: repeat(4, 1fr);
  }

  .metrics__item {
    border-bottom: none;
  }

  .metrics__item:nth-child(2n) { border-right: 1px solid var(--color-border); }
  .metrics__item:nth-child(4n) { border-right: none; }
  .metrics__item:nth-child(3),
  .metrics__item:nth-child(4) { border-bottom: none; }

  /* Modules grid */
  .modules-scroll { margin: 0; padding: 0 0 8px; overflow: visible; }

  .modules-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    width: 100%;
  }

  .card-module { width: auto; }

  /* Services */
  .services__grid {
    grid-template-columns: repeat(2, 1fr);
  }

  /* Advantages */
  .advantages__features {
    grid-template-columns: repeat(3, 1fr);
  }

  /* Cases */
  .cases__grid {
    grid-template-columns: repeat(2, 1fr);
  }

  /* About */
  .about__inner {
    grid-template-columns: 1fr 1fr;
    align-items: center;
  }

  /* Courses */
  .courses__formats {
    grid-template-columns: repeat(2, 1fr);
  }

  .courses__format-card {
    border-bottom: none;
    border-right: 1px solid var(--color-border);
  }

  .courses__format-card:last-child { border-right: none; }

  /* CTA Form */
  .cta-form__grid {
    grid-template-columns: repeat(2, 1fr);
  }

  /* Footer */
  .footer__grid {
    grid-template-columns: repeat(2, 1fr);
  }

  /* Hero */
  .hero__inner {
    flex-direction: row;
    align-items: center;
    justify-content: space-between;
    text-align: left;
  }

  .hero__content {
    text-align: left;
    align-items: flex-start;
    max-width: 520px;
  }

  .hero__actions { justify-content: flex-start; }
  .hero__illustration { max-width: 360px; }
}

/* ============================================================
   RESPONSIVE — Desktop S (1024px+)
   ============================================================ */

@media (min-width: 1024px) {

  :root {
    --container-pad: 48px;
  }

  /* Header */
  .header__nav { display: flex; }

  .burger { display: none; }

  .header__actions .btn { display: inline-flex; }

  /* Modules */
  .modules-grid {
    grid-template-columns: repeat(4, 1fr);
  }

  /* Services */
  .services__grid {
    grid-template-columns: repeat(3, 1fr);
  }

  /* Cases */
  .cases__grid {
    grid-template-columns: repeat(3, 1fr);
  }

  /* Footer */
  .footer__grid {
    grid-template-columns: 2fr 1fr 1fr 1.5fr;
  }

  /* Footer bottom */
  .footer__bottom {
    flex-direction: row;
    justify-content: space-between;
  }

  /* Advantages inner */
  .advantages__inner {
    grid-template-columns: 1fr 1fr;
    align-items: start;
  }
}

/* ============================================================
   RESPONSIVE — Desktop L (1280px+)
   ============================================================ */

@media (min-width: 1280px) {

  :root {
    --container-pad: 0px;
  }

  .modules-grid {
    grid-template-columns: repeat(5, 1fr);
  }
}

/* ============================================================
   REDUCED MOTION
   ============================================================ */

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }

  html { scroll-behavior: auto; }

  .reveal {
    opacity: 1;
    transform: none;
  }
}