/* ============================================================
   CSS Variables & Reset
   ============================================================ */

:root {
  --color-bg: #ffffff;
  --color-bg-alt: #f5f7fa;
  --color-text: #2d3436;
  --color-text-muted: #636e72;
  --color-primary: #0984e3;
  --color-primary-dark: #0767b3;
  --color-primary-light: #e8f4fd;
  --color-border: #dfe6e9;
  --color-card-bg: #ffffff;
  --color-overlay: rgba(0, 0, 0, 0.5);

  --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  --font-size-sm: 0.875rem;
  --font-size-base: 1rem;
  --font-size-md: 1.125rem;
  --font-size-lg: 1.5rem;
  --font-size-xl: 2rem;
  --font-size-2xl: 2.75rem;

  --spacing-xs: 0.5rem;
  --spacing-sm: 1rem;
  --spacing-md: 1.5rem;
  --spacing-lg: 2.5rem;
  --spacing-xl: 4rem;
  --spacing-2xl: 6rem;

  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;

  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.06);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 8px 30px rgba(0, 0, 0, 0.1);

  --header-height: 64px;
  --max-width: 1200px;
  --transition: 0.25s ease;
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: var(--header-height);
}

body {
  font-family: var(--font-family);
  font-size: var(--font-size-base);
  line-height: 1.6;
  color: var(--color-text);
  background-color: var(--color-bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color var(--transition);
}

a:hover {
  color: var(--color-primary-dark);
}

ul {
  list-style: none;
}

/* Focus styles for accessibility */
:focus-visible {
  outline: 3px solid var(--color-primary);
  outline-offset: 2px;
}

/* ============================================================
   Utility classes
   ============================================================ */

.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--spacing-sm);
}

.section {
  padding: var(--spacing-xl) 0;
}

.section[hidden] {
  display: none;
}

.section--alt {
  background-color: var(--color-bg-alt);
}

.section__title {
  font-size: var(--font-size-xl);
  font-weight: 700;
  text-align: center;
  margin-bottom: var(--spacing-lg);
  color: var(--color-text);
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-xs);
  padding: 0.75rem 1.5rem;
  font-size: var(--font-size-base);
  font-weight: 600;
  font-family: inherit;
  border: 2px solid transparent;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: all var(--transition);
  text-decoration: none;
  line-height: 1.4;
  white-space: nowrap;
}

.btn--primary {
  background-color: var(--color-primary);
  color: #ffffff;
  border-color: var(--color-primary);
}

.btn--primary:hover {
  background-color: var(--color-primary-dark);
  border-color: var(--color-primary-dark);
  color: #ffffff;
}

.btn--outline {
  background-color: transparent;
  color: var(--color-primary);
  border-color: var(--color-primary);
}

.btn--outline:hover {
  background-color: var(--color-primary);
  color: #ffffff;
}

.btn--sm {
  padding: 0.5rem 1rem;
  font-size: var(--font-size-sm);
}

.btn--full {
  width: 100%;
}

.btn--icon {
  padding: 0.5rem 1rem;
  font-size: var(--font-size-sm);
}

/* Cards */
.card {
  background-color: var(--color-card-bg);
  border-radius: var(--radius-md);
  padding: var(--spacing-md);
  box-shadow: var(--shadow-sm);
  transition: transform var(--transition), box-shadow var(--transition);
}

.card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

/* ============================================================
   Loading Screen
   ============================================================ */

.loading-screen {
  position: fixed;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  background-color: var(--color-bg);
  z-index: 9999;
  transition: opacity 0.3s ease;
}

.loading-screen[hidden] {
  opacity: 0;
  pointer-events: none;
}

.loading-screen__spinner {
  width: 40px;
  height: 40px;
  border: 3px solid var(--color-border);
  border-top-color: var(--color-primary);
  border-radius: 50%;
  animation: spin 0.7s linear infinite;
}

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

/* ============================================================
   Header
   ============================================================ */

.header {
  position: sticky;
  top: 0;
  z-index: 100;
  background-color: var(--color-bg);
  border-bottom: 1px solid var(--color-border);
  height: var(--header-height);
}

.header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
  gap: var(--spacing-sm);
}

.header__logo {
  font-size: var(--font-size-md);
  font-weight: 700;
  color: var(--color-text);
  text-decoration: none;
  flex-shrink: 0;
}

.header__logo:hover {
  color: var(--color-primary);
}

.header__nav {
  display: none;
}

.header__menu {
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
}

.header__menu a {
  display: block;
  padding: 0.4rem 0.75rem;
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  border-radius: var(--radius-sm);
  transition: color var(--transition), background-color var(--transition);
  white-space: nowrap;
}

.header__menu a:hover,
.header__menu a:focus-visible {
  color: var(--color-primary);
  background-color: var(--color-primary-light);
}

.header__actions {
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
  flex-shrink: 0;
}

/* Burger */
.burger {
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 36px;
  height: 36px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 6px;
  border-radius: var(--radius-sm);
  transition: background-color var(--transition);
}

.burger:hover {
  background-color: var(--color-bg-alt);
}

.burger__line {
  display: block;
  width: 100%;
  height: 2px;
  background-color: var(--color-text);
  border-radius: 1px;
  transition: transform var(--transition), opacity var(--transition);
}

.burger[aria-expanded="true"] .burger__line:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.burger[aria-expanded="true"] .burger__line:nth-child(2) {
  opacity: 0;
}

.burger[aria-expanded="true"] .burger__line:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* Mobile nav overlay */
.header__nav--open {
  display: flex;
  position: fixed;
  top: var(--header-height);
  left: 0;
  right: 0;
  bottom: 0;
  background-color: var(--color-bg);
  z-index: 99;
  padding: var(--spacing-md);
  overflow-y: auto;
}

.header__nav--open .header__menu {
  flex-direction: column;
  align-items: stretch;
  width: 100%;
  gap: 0;
}

.header__nav--open .header__menu a {
  padding: 0.75rem var(--spacing-sm);
  font-size: var(--font-size-md);
  border-bottom: 1px solid var(--color-border);
}

/* ============================================================
   Hero
   ============================================================ */

.hero {
  padding: var(--spacing-2xl) 0 var(--spacing-xl);
  text-align: center;
}

.hero__title {
  font-size: var(--font-size-xl);
  font-weight: 800;
  line-height: 1.2;
  margin-bottom: var(--spacing-sm);
  color: var(--color-text);
}

.hero__subtitle {
  font-size: var(--font-size-md);
  color: var(--color-text-muted);
  max-width: 640px;
  margin: 0 auto var(--spacing-lg);
  line-height: 1.6;
}

.hero__advantages {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-lg);
}

.hero__advantage {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.5rem 1rem;
  background-color: var(--color-bg-alt);
  border-radius: 50px;
  font-size: var(--font-size-sm);
  color: var(--color-text);
}

.hero__advantage::before {
  content: '✓';
  color: var(--color-primary);
  font-weight: 700;
}

.hero__cta {
  display: flex;
  justify-content: center;
  gap: var(--spacing-sm);
  flex-wrap: wrap;
}

/* ============================================================
   Services
   ============================================================ */

.services-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--spacing-md);
}

.service-card {
  text-align: center;
}

.service-card__icon {
  font-size: 2rem;
  margin-bottom: var(--spacing-xs);
  display: block;
}

.service-card__title {
  font-size: var(--font-size-md);
  font-weight: 600;
  margin-bottom: var(--spacing-xs);
}

.service-card__desc {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  line-height: 1.5;
}

/* ============================================================
   Portfolio
   ============================================================ */

.portfolio-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--spacing-md);
}

.portfolio-item {
  border-radius: var(--radius-md);
  overflow: hidden;
  cursor: pointer;
  position: relative;
}

.portfolio-item__img {
  width: 100%;
  aspect-ratio: 4 / 3;
  object-fit: cover;
  background-color: var(--color-bg-alt);
  transition: transform var(--transition);
}

.portfolio-item:hover .portfolio-item__img {
  transform: scale(1.03);
}

.portfolio-item__caption {
  padding: var(--spacing-sm);
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
}

/* Lightbox */
.lightbox {
  position: fixed;
  inset: 0;
  background-color: rgba(0, 0, 0, 0.85);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 200;
  padding: var(--spacing-md);
  cursor: pointer;
}

.lightbox[hidden] {
  display: none;
}

.lightbox__img {
  max-width: 90vw;
  max-height: 85vh;
  object-fit: contain;
  border-radius: var(--radius-sm);
}

.lightbox__close {
  position: absolute;
  top: var(--spacing-sm);
  right: var(--spacing-sm);
  background: rgba(255, 255, 255, 0.15);
  border: none;
  color: #ffffff;
  font-size: 2rem;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background-color var(--transition);
}

.lightbox__close:hover {
  background: rgba(255, 255, 255, 0.3);
}

/* ============================================================
   Workflow
   ============================================================ */

.workflow-steps {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--spacing-md);
  position: relative;
}

.workflow-step {
  display: flex;
  gap: var(--spacing-sm);
  align-items: flex-start;
}

.workflow-step__number {
  flex-shrink: 0;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background-color: var(--color-primary);
  color: #ffffff;
  font-weight: 700;
  font-size: var(--font-size-md);
  display: flex;
  align-items: center;
  justify-content: center;
}

.workflow-step__content {
  flex: 1;
}

.workflow-step__title {
  font-weight: 600;
  font-size: var(--font-size-md);
  margin-bottom: 0.25rem;
}

.workflow-step__desc {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  line-height: 1.5;
}

/* ============================================================
   Geography
   ============================================================ */

.geography__desc {
  text-align: center;
  color: var(--color-text-muted);
  margin-bottom: var(--spacing-md);
  font-size: var(--font-size-md);
}

.geography-tags {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: var(--spacing-xs);
}

.geography-tag {
  padding: 0.4rem 1rem;
  background-color: var(--color-primary-light);
  color: var(--color-primary-dark);
  border-radius: 50px;
  font-size: var(--font-size-sm);
  font-weight: 500;
}

/* ============================================================
   Reviews
   ============================================================ */

.reviews-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--spacing-md);
}

.review-card {
  position: relative;
}

.review-card__text {
  font-size: var(--font-size-base);
  line-height: 1.6;
  color: var(--color-text);
  margin-bottom: var(--spacing-sm);
  font-style: italic;
}

.review-card__text::before {
  content: '«';
  color: var(--color-primary);
  font-weight: 700;
}

.review-card__text::after {
  content: '»';
  color: var(--color-primary);
  font-weight: 700;
}

.review-card__author {
  font-size: var(--font-size-sm);
  font-weight: 600;
  color: var(--color-text);
}

.review-card__date {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
}

/* ============================================================
   FAQ
   ============================================================ */

.faq-list {
  max-width: 800px;
  margin: 0 auto;
}

.faq-item {
  border-bottom: 1px solid var(--color-border);
}

.faq-item__question {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--spacing-sm);
  padding: var(--spacing-sm) 0;
  background: none;
  border: none;
  font-family: inherit;
  font-size: var(--font-size-base);
  font-weight: 600;
  color: var(--color-text);
  cursor: pointer;
  text-align: left;
  line-height: 1.5;
  transition: color var(--transition);
}

.faq-item__question:hover {
  color: var(--color-primary);
}

.faq-item__icon {
  flex-shrink: 0;
  width: 24px;
  height: 24px;
  position: relative;
  transition: transform var(--transition);
}

.faq-item__icon::before,
.faq-item__icon::after {
  content: '';
  position: absolute;
  background-color: currentColor;
  border-radius: 1px;
  top: 50%;
  left: 50%;
}

.faq-item__icon::before {
  width: 14px;
  height: 2px;
  transform: translate(-50%, -50%);
}

.faq-item__icon::after {
  width: 2px;
  height: 14px;
  transform: translate(-50%, -50%);
  transition: transform var(--transition);
}

.faq-item[data-open="true"] .faq-item__icon::after {
  transform: translate(-50%, -50%) rotate(90deg);
}

.faq-item__answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease, padding 0.3s ease;
}

.faq-item__answer-inner {
  padding: 0 0 var(--spacing-sm);
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  line-height: 1.7;
}

.faq-item[data-open="true"] .faq-item__answer {
  max-height: 500px;
}

/* ============================================================
   Contacts
   ============================================================ */

.contacts-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--spacing-lg);
  justify-items: center;
}

.contacts-info {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  gap: var(--spacing-md);
}

.contact-row {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.25rem;
}

.contact-row__label {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  min-width: 100px;
  flex-shrink: 0;
}

.contact-row__value {
  font-weight: 500;
}

.contact-row__value a {
  color: var(--color-primary);
}

.contacts-messengers {
  display: flex;
  justify-content: center;
  gap: var(--spacing-sm);
  flex-wrap: wrap;
}

.contacts-map {
  border-radius: var(--radius-md);
  overflow: hidden;
  min-height: 300px;
}

.contacts-map iframe {
  width: 100%;
  height: 300px;
  border: none;
}

/* ============================================================
   Requisites
   ============================================================ */

.requisites-list {
  max-width: 600px;
  margin: 0 auto;
}

.requisite-row {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  padding: var(--spacing-xs) 0;
  border-bottom: 1px solid var(--color-border);
  gap: var(--spacing-sm);
}

.requisite-row:last-child {
  border-bottom: none;
}

.requisite-row__label {
  color: var(--color-text-muted);
  font-size: var(--font-size-sm);
  flex-shrink: 0;
}

.requisite-row__value {
  font-weight: 500;
  text-align: right;
}

/* ============================================================
   Footer
   ============================================================ */

.footer {
  background-color: var(--color-text);
  color: rgba(255, 255, 255, 0.7);
  padding: var(--spacing-lg) 0;
}

.footer__inner {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--spacing-sm);
  text-align: center;
}

.footer__copyright {
  font-size: var(--font-size-sm);
}

.footer__privacy {
  font-size: var(--font-size-sm);
  opacity: 0.7;
  max-width: 500px;
  line-height: 1.5;
}

/* ============================================================
   Modal
   ============================================================ */

.modal-overlay {
  position: fixed;
  inset: 0;
  background-color: var(--color-overlay);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 300;
  padding: var(--spacing-sm);
  opacity: 1;
  transition: opacity 0.2s ease;
}

.modal-overlay[hidden] {
  display: none;
}

.modal {
  background-color: var(--color-bg);
  border-radius: var(--radius-lg);
  padding: var(--spacing-lg);
  width: 100%;
  max-width: 480px;
  position: relative;
  max-height: 90vh;
  overflow-y: auto;
}

.modal__close {
  position: absolute;
  top: var(--spacing-sm);
  right: var(--spacing-sm);
  background: none;
  border: none;
  font-size: 1.5rem;
  cursor: pointer;
  color: var(--color-text-muted);
  width: 36px;
  height: 36px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  transition: background-color var(--transition), color var(--transition);
}

.modal__close:hover {
  background-color: var(--color-bg-alt);
  color: var(--color-text);
}

.modal__title {
  font-size: var(--font-size-lg);
  font-weight: 700;
  margin-bottom: var(--spacing-md);
}

.form-group {
  margin-bottom: var(--spacing-sm);
}

.form-group label {
  display: block;
  font-size: var(--font-size-sm);
  font-weight: 500;
  margin-bottom: 0.25rem;
  color: var(--color-text);
}

.form-group input,
.form-group textarea {
  width: 100%;
  padding: 0.65rem 0.85rem;
  font-size: var(--font-size-base);
  font-family: inherit;
  border: 1.5px solid var(--color-border);
  border-radius: var(--radius-sm);
  background-color: var(--color-bg);
  color: var(--color-text);
  transition: border-color var(--transition), box-shadow var(--transition);
}

.form-group input:focus,
.form-group textarea:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px var(--color-primary-light);
}

.form-group input.is-invalid,
.form-group textarea.is-invalid {
  border-color: #d63031;
}

.form-group textarea {
  resize: vertical;
  min-height: 60px;
}

.form-privacy {
  font-size: 0.75rem;
  color: var(--color-text-muted);
  margin-top: var(--spacing-sm);
  line-height: 1.4;
}

.modal__success,
.modal__fallback {
  text-align: center;
}

.modal__success p,
.modal__fallback p {
  margin-bottom: var(--spacing-sm);
}

/* ============================================================
   Error state
   ============================================================ */

.error-message {
  max-width: 600px;
  margin: 120px auto;
  padding: var(--spacing-lg);
  text-align: center;
}

.error-message h1 {
  font-size: var(--font-size-lg);
  margin-bottom: var(--spacing-sm);
}

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

/* ============================================================
   Fade-in animation (Intersection Observer)
   ============================================================ */

.fade-in {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.5s ease, transform 0.5s ease;
}

.fade-in--visible {
  opacity: 1;
  transform: translateY(0);
}

/* ============================================================
   Responsive: Tablet (≥768px)
   ============================================================ */

@media (min-width: 768px) {
  :root {
    --spacing-sm: 1.25rem;
  }

  .container {
    padding: 0 var(--spacing-md);
  }

  .section {
    padding: var(--spacing-2xl) 0;
  }

  .section__title {
    font-size: var(--font-size-2xl);
    margin-bottom: var(--spacing-xl);
  }

  .hero {
    padding: calc(var(--spacing-2xl) * 1.5) 0 var(--spacing-2xl);
  }

  .hero__title {
    font-size: var(--font-size-2xl);
  }

  .hero__subtitle {
    font-size: var(--font-size-md);
  }

  .services-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .portfolio-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .workflow-steps {
    grid-template-columns: repeat(2, 1fr);
  }

  .reviews-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .contacts-grid {
    grid-template-columns: 1fr 1fr;
  }

  .contacts-info:only-child {
    grid-column: 1 / -1;
  }

  .contacts-map iframe {
    height: 100%;
    min-height: 300px;
  }

  /* Desktop nav */
  .header__nav {
    display: flex;
  }

  .burger {
    display: none;
  }
}

/* ============================================================
   Responsive: Desktop (≥1024px)
   ============================================================ */

@media (min-width: 1024px) {
  .services-grid {
    grid-template-columns: repeat(3, 1fr);
  }

  .hero__title {
    font-size: 3rem;
  }

  .workflow-steps {
    grid-template-columns: repeat(3, 1fr);
  }

  .reviews-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

/* ============================================================
   Print styles
   ============================================================ */

@media print {
  .header,
  .burger,
  .modal-overlay,
  .lightbox,
  .loading-screen {
    display: none !important;
  }

  .section {
    padding: 1rem 0;
    break-inside: avoid;
  }

  body {
    font-size: 12pt;
    color: #000;
  }

  a {
    color: #000;
  }
}