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

:root {
  --blue-50: #eff6ff;
  --blue-100: #dbeafe;
  --blue-600: #2563eb;
  --blue-700: #1d4ed8;
  --blue-800: #1e40af;
  --indigo-50: #eef2ff;
  --gray-50: #f9fafb;
  --gray-100: #f3f4f6;
  --gray-300: #d1d5db;
  --gray-500: #6b7280;
  --gray-600: #4b5563;
  --gray-700: #374151;
  --gray-800: #1f2937;
  --gray-900: #111827;
  --green-600: #16a34a;
  --green-700: #15803d;
  --red-600: #dc2626;
  --red-700: #b91c1c;
}

body {
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  line-height: 1.6;
  color: var(--gray-900);
  background-color: var(--gray-50);
}

/* Header Styles */
header {
  background: white;
  box-shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1);
  position: sticky;
  top: 0;
  z-index: 50;
}

.header-container {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0.75rem 1rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.header-title {
  font-size: 1.25rem;
  font-weight: bold;
  color: var(--blue-900);
}

nav {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

nav a {
  padding: 0.375rem 0.75rem;
  font-size: 0.875rem;
  border-radius: 0.25rem;
  font-weight: 500;
  text-decoration: none;
  color: var(--gray-700);
  transition: all 0.2s;
}

nav a:hover {
  background-color: var(--blue-600);
  color: white;
}

/* Hero Section */
.hero {
  background: linear-gradient(to right, var(--blue-600), var(--blue-800));
  color: white;
  padding: 4rem 1rem;
}

.hero-container {
  max-width: 1280px;
  margin: 0 auto;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2rem;
  align-items: center;
}

@media (min-width: 768px) {
  .hero-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

.hero h2 {
  font-size: 2.25rem;
  font-weight: bold;
  margin-bottom: 1rem;
}

.hero p {
  font-size: 1.125rem;
  margin-bottom: 1rem;
}

.hero-features {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.hero-feature {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.hero-card {
  background-color: var(--blue-700);
  border-radius: 0.5rem;
  padding: 2rem;
  text-align: center;
}

.hero-icon {
  font-size: 4rem;
  margin-bottom: 1rem;
}

.hero-card-title {
  font-size: 1.25rem;
  font-weight: 600;
}

.hero-card-text {
  color: rgba(255, 255, 255, 0.8);
  margin-top: 1rem;
}

/* Section Styles */
section {
  padding: 3rem 1rem;
}

section.bg-white {
  background-color: white;
}

section.bg-gray {
  background-color: var(--gray-50);
}

.section-container {
  max-width: 1280px;
  margin: 0 auto;
}

.section-title {
  font-size: 1.875rem;
  font-weight: bold;
  margin-bottom: 0.5rem;
  color: var(--gray-900);
}

.section-subtitle {
  color: var(--gray-600);
  margin-bottom: 2rem;
}

.subsection-title {
  font-size: 1.5rem;
  font-weight: bold;
  margin-bottom: 1.5rem;
  color: var(--gray-900);
}

/* Grid Layouts */
.grid {
  display: grid;
  gap: 1.5rem;
}

.grid-2 {
  grid-template-columns: 1fr;
}

.grid-3 {
  grid-template-columns: 1fr;
}

.grid-4 {
  grid-template-columns: 1fr;
}

@media (min-width: 768px) {
  .grid-2 {
    grid-template-columns: repeat(2, 1fr);
  }
  
  .grid-3 {
    grid-template-columns: repeat(2, 1fr);
  }
  
  .grid-4 {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 1024px) {
  .grid-3 {
    grid-template-columns: repeat(3, 1fr);
  }
  
  .grid-4 {
    grid-template-columns: repeat(4, 1fr);
  }
}

/* Card Styles */
.card {
  background: white;
  border-radius: 0.5rem;
  box-shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1);
  padding: 1.5rem;
  transition: transform 0.2s, box-shadow 0.2s;
}

.card:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
}

.card-header {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 1rem;
}

.card-icon {
  font-size: 2rem;
}

.card-title {
  font-size: 1.125rem;
  font-weight: bold;
  color: var(--gray-900);
}

.card-description {
  color: var(--gray-600);
  margin-bottom: 1rem;
  font-size: 0.875rem;
}

.card-details {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.card-detail-item {
  display: flex;
  align-items: start;
  gap: 0.5rem;
  color: var(--gray-700);
  font-size: 0.875rem;
}

.detail-bullet {
  color: var(--blue-600);
  font-weight: bold;
}

/* Standard Card */
.standard-card {
  background: white;
  border-radius: 0.5rem;
  box-shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1);
  padding: 1.5rem;
}

.standard-card-header {
  margin-bottom: 1rem;
}

.standard-category {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--blue-600);
  background-color: var(--blue-50);
  padding: 0.25rem 0.75rem;
  border-radius: 9999px;
  margin-bottom: 0.5rem;
}

.standard-title {
  font-size: 1.25rem;
  font-weight: bold;
  color: var(--gray-900);
}

.standard-description {
  color: var(--gray-600);
  margin-bottom: 1rem;
}

/* Cable Card */
.cable-card {
  background: white;
  border-radius: 0.5rem;
  box-shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1);
  padding: 1.5rem;
}

.cable-card-header {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 1rem;
}

.cable-icon {
  font-size: 2rem;
}

.cable-title {
  font-size: 1.125rem;
  font-weight: bold;
  color: var(--gray-900);
}

.cable-section {
  margin-bottom: 1rem;
}

.cable-section:last-child {
  margin-bottom: 0;
}

.cable-section-title {
  font-weight: 600;
  color: var(--gray-800);
  margin-bottom: 0.5rem;
  font-size: 0.875rem;
}

.cable-list {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}

.cable-list-item {
  display: flex;
  align-items: start;
  gap: 0.5rem;
  font-size: 0.875rem;
  color: var(--gray-700);
}

.pros-bullet {
  color: var(--green-600);
  font-weight: bold;
}

.cons-bullet {
  color: var(--red-600);
  font-weight: bold;
}

/* Category Card */
.category-card {
  background: white;
  border-radius: 0.5rem;
  box-shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1);
  padding: 1rem;
}

.category-title {
  font-size: 1.125rem;
  font-weight: bold;
  color: var(--blue-600);
  margin-bottom: 0.75rem;
}

.category-info {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  font-size: 0.875rem;
}

.category-info-label {
  font-weight: 600;
  color: var(--gray-700);
}

/* Parameter Card */
.parameter-card {
  background: white;
  border-radius: 0.5rem;
  box-shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1);
  padding: 1rem;
}

.parameter-title {
  font-weight: bold;
  color: var(--blue-600);
  margin-bottom: 0.5rem;
}

.parameter-description {
  font-size: 0.875rem;
  color: var(--gray-700);
  margin-bottom: 0.75rem;
}

.parameter-unit {
  font-size: 0.75rem;
  background-color: var(--blue-50);
  color: var(--blue-800);
  padding: 0.25rem 0.5rem;
  border-radius: 0.25rem;
  display: inline-block;
}

/* Protocol Card */
.protocol-card {
  background: white;
  border-radius: 0.5rem;
  box-shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1);
  padding: 2rem;
  margin-top: 3rem;
}

.protocol-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
}

@media (min-width: 768px) {
  .protocol-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

.protocol-section-title {
  font-weight: bold;
  color: var(--gray-900);
  margin-bottom: 0.75rem;
}

.protocol-list {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.protocol-list-item {
  display: flex;
  align-items: start;
  gap: 0.5rem;
  color: var(--gray-700);
}

.passport-box {
  background-color: var(--blue-50);
  border-radius: 0.25rem;
  padding: 1rem;
}

.passport-title {
  font-weight: bold;
  color: var(--gray-900);
  margin-bottom: 0.75rem;
}

.passport-description {
  color: var(--gray-700);
  margin-bottom: 0.75rem;
}

.passport-list {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
  font-size: 0.875rem;
  color: var(--gray-700);
}

/* Example Card */
.example-card {
  background: white;
  border-radius: 0.5rem;
  box-shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1);
  padding: 1.5rem;
}

.example-card-header {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 1rem;
}

.example-icon {
  font-size: 2rem;
}

.example-title {
  font-size: 1.125rem;
  font-weight: bold;
  color: var(--gray-900);
}

.example-description {
  color: var(--gray-600);
  margin-bottom: 1rem;
  font-size: 0.875rem;
}

.example-section {
  margin-bottom: 1rem;
}

.example-section:last-child {
  margin-bottom: 0;
}

.example-section-title {
  font-weight: 600;
  color: var(--gray-800);
  margin-bottom: 0.5rem;
  font-size: 0.875rem;
}

.example-list {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}

.example-list-item {
  display: flex;
  align-items: start;
  gap: 0.5rem;
  font-size: 0.875rem;
  color: var(--gray-700);
}

/* Recommendations */
.recommendations {
  margin-top: 3rem;
  background: linear-gradient(to right, var(--blue-50), var(--indigo-50));
  border-radius: 0.5rem;
  padding: 2rem;
}

.recommendations-title {
  font-size: 1.5rem;
  font-weight: bold;
  margin-bottom: 1rem;
  color: var(--gray-900);
}

.recommendations-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
}

@media (min-width: 768px) {
  .recommendations-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

.recommendation-section-title {
  font-weight: bold;
  color: var(--gray-900);
  margin-bottom: 0.75rem;
}

.recommendation-list {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.recommendation-item {
  display: flex;
  align-items: start;
  gap: 0.5rem;
  color: var(--gray-700);
}

.check-icon {
  color: var(--blue-600);
  font-weight: bold;
}

/* Footer */
footer {
  background-color: var(--gray-900);
  color: var(--gray-300);
  padding: 2rem 1rem;
}

.footer-container {
  max-width: 1280px;
  margin: 0 auto;
  text-align: center;
}

.footer-text {
  font-size: 0.875rem;
  color: var(--gray-500);
}

/* Utility Classes */
.mb-12 {
  margin-bottom: 3rem;
}

/* Publications Section */
.pub-columns {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2.5rem;
}

@media (min-width: 900px) {
  .pub-columns {
    grid-template-columns: repeat(2, 1fr);
  }
}

.pub-group-title {
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--gray-800);
  margin-bottom: 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 2px solid var(--blue-100);
}

.pub-list {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.pub-card {
  background: white;
  border-radius: 0.5rem;
  box-shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1);
  padding: 1.25rem 1.5rem;
  border-left: 3px solid var(--blue-600);
  transition: box-shadow 0.2s, transform 0.2s;
}

.pub-card:hover {
  box-shadow: 0 4px 10px -2px rgba(0, 0, 0, 0.12);
  transform: translateY(-1px);
}

.pub-card-top {
  display: flex;
  align-items: flex-start;
  gap: 0.625rem;
  margin-bottom: 0.375rem;
}

.pub-badge {
  flex-shrink: 0;
  margin-top: 0.15rem;
  font-size: 0.6875rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  padding: 0.15rem 0.5rem;
  border-radius: 9999px;
}

.pub-badge-ru {
  background-color: #fef3c7;
  color: #92400e;
}

.pub-badge-en {
  background-color: var(--blue-50);
  color: var(--blue-800);
}

.pub-title {
  font-size: 0.9375rem;
  font-weight: 600;
  color: var(--blue-700);
  text-decoration: none;
  line-height: 1.4;
}

.pub-title:hover {
  text-decoration: underline;
  color: var(--blue-800);
}

.pub-authors {
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--gray-700);
  margin-bottom: 0.2rem;
}

.pub-source {
  font-size: 0.8125rem;
  color: var(--gray-500);
  font-style: italic;
  margin-bottom: 0.625rem;
}

.pub-description {
  font-size: 0.875rem;
  color: var(--gray-600);
  line-height: 1.55;
}

/* Smooth Scroll */
html {
  scroll-behavior: smooth;
}