/* ========================================
   KETHEP - Main Stylesheet
   ======================================== */

/* CSS Custom Properties (Variables) */
:root {
  /* Colors */
  --color-primary: #2563eb;
  --color-primary-dark: #1d4ed8;
  --color-primary-light: #3b82f6;
  --color-secondary: #10b981;
  --color-secondary-dark: #059669;
  --color-secondary-light: #34d399;
  
  --color-text-primary: #1f2937;
  --color-text-secondary: #6b7280;
  --color-text-light: #9ca3af;
  
  --color-background: #ffffff;
  --color-background-alt: #f9fafb;
  --color-background-dark: #f3f4f6;
  
  --color-border: #e5e7eb;
  --color-border-dark: #d1d5db;
  
  /* Typography */
  --font-primary: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-heading: 'Manrope', var(--font-primary);
  
  --font-size-xs: 0.75rem;
  --font-size-sm: 0.875rem;
  --font-size-base: 1rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.25rem;
  --font-size-2xl: 1.5rem;
  --font-size-3xl: 1.875rem;
  --font-size-4xl: 2.25rem;
  --font-size-5xl: 3rem;
  
  --font-weight-light: 300;
  --font-weight-regular: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --font-weight-bold: 700;
  
  --line-height-tight: 1.25;
  --line-height-normal: 1.5;
  --line-height-relaxed: 1.75;
  
  /* Spacing */
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2rem;
  --spacing-2xl: 3rem;
  --spacing-3xl: 4rem;
  --spacing-4xl: 6rem;
  
  /* Border Radius */
  --radius-sm: 0.25rem;
  --radius-md: 0.375rem;
  --radius-lg: 0.5rem;
  --radius-xl: 0.75rem;
  --radius-full: 9999px;
  
  /* Shadows */
  --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
  --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
  --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
  --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);
  
  /* Transitions */
  --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-base: 300ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 500ms cubic-bezier(0.4, 0, 0.2, 1);
  
  /* Z-index */
  --z-dropdown: 10;
  --z-sticky: 20;
  --z-modal: 30;
  --z-tooltip: 40;
}

/* ========================================
   Reset & Base Styles
   ======================================== */

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

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

/* ========================================
   Typography
   ======================================== */

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  font-weight: var(--font-weight-bold);
  line-height: var(--line-height-tight);
  color: var(--color-text-primary);
  margin-bottom: var(--spacing-md);
}

h1 {
  font-size: clamp(var(--font-size-3xl), 5vw, var(--font-size-5xl));
}

h2 {
  font-size: clamp(var(--font-size-2xl), 4vw, var(--font-size-4xl));
}

h3 {
  font-size: clamp(var(--font-size-xl), 3vw, var(--font-size-3xl));
}

h4 {
  font-size: var(--font-size-xl);
}

h5 {
  font-size: var(--font-size-lg);
}

h6 {
  font-size: var(--font-size-base);
}

p {
  margin-bottom: var(--spacing-md);
  line-height: var(--line-height-relaxed);
}

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

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

a:focus {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

strong {
  font-weight: var(--font-weight-semibold);
}

/* Lists */
ul, ol {
  margin-bottom: var(--spacing-md);
  padding-left: var(--spacing-lg);
}

li {
  margin-bottom: var(--spacing-xs);
}

/* ========================================
   Layout Components
   ======================================== */

.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--spacing-md);
}

@media (min-width: 768px) {
  .container {
    padding: 0 var(--spacing-lg);
  }
}

/* Skip Link (Accessibility) */
.skip-link {
  position: absolute;
  top: -40px;
  left: 0;
  background: var(--color-primary);
  color: white;
  padding: var(--spacing-sm) var(--spacing-md);
  border-radius: var(--radius-md);
  text-decoration: none;
  z-index: 100;
}

.skip-link:focus {
  top: var(--spacing-sm);
}

/* ========================================
   Header & Navigation
   ======================================== */

.site-header {
  background: var(--color-background);
  border-bottom: 1px solid var(--color-border);
  position: sticky;
  top: 0;
  z-index: var(--z-sticky);
  box-shadow: var(--shadow-sm);
}

.header-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--spacing-md) 0;
}

/* Logo */
.logo a {
  display: flex;
  flex-direction: column;
  text-decoration: none;
  color: var(--color-text-primary);
}

.logo-text {
  font-family: var(--font-heading);
  font-size: var(--font-size-2xl);
  font-weight: var(--font-weight-bold);
  color: var(--color-primary);
}

.logo-subtitle {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  font-weight: var(--font-weight-medium);
}

/* Navigation */
.main-nav {
  display: flex;
  align-items: center;
}

.nav-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--spacing-sm);
}

.hamburger {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--color-text-primary);
  position: relative;
  transition: background var(--transition-fast);
}

.hamburger::before,
.hamburger::after {
  content: '';
  position: absolute;
  width: 100%;
  height: 100%;
  background: var(--color-text-primary);
  transition: transform var(--transition-fast);
}

.hamburger::before {
  transform: translateY(-8px);
}

.hamburger::after {
  transform: translateY(8px);
}

.nav-list {
  display: flex;
  list-style: none;
  margin: 0;
  padding: 0;
  gap: var(--spacing-xs);
}

.nav-list a {
  padding: var(--spacing-sm) var(--spacing-md);
  color: var(--color-text-primary);
  font-weight: var(--font-weight-medium);
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
}

.nav-list a:hover,
.nav-list a.active {
  background: var(--color-background-alt);
  color: var(--color-primary);
}

/* Dropdown Menu */
.has-dropdown {
  position: relative;
}

.dropdown-menu {
  position: absolute;
  top: 100%;
  left: 0;
  background: var(--color-background);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  min-width: 200px;
  opacity: 0;
  visibility: hidden;
  transform: translateY(-10px);
  transition: all var(--transition-fast);
  z-index: var(--z-dropdown);
  list-style: none;
  padding: var(--spacing-sm);
  margin-top: var(--spacing-sm);
}

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

.dropdown-menu li {
  margin: 0;
}

.dropdown-menu a {
  display: block;
  padding: var(--spacing-sm) var(--spacing-md);
  border-radius: var(--radius-md);
  white-space: nowrap;
}

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

.hero {
  background: linear-gradient(135deg, var(--color-background-alt) 0%, var(--color-background) 100%);
  padding: var(--spacing-4xl) 0;
  text-align: center;
}

.hero-content {
  max-width: 800px;
  margin: 0 auto;
}

.hero-title {
  font-size: clamp(var(--font-size-3xl), 6vw, var(--font-size-5xl));
  margin-bottom: var(--spacing-lg);
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-secondary) 100%);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-subtitle {
  font-size: var(--font-size-xl);
  color: var(--color-text-secondary);
  font-weight: var(--font-weight-medium);
  margin-bottom: var(--spacing-md);
}

.hero-description {
  font-size: var(--font-size-lg);
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-2xl);
  line-height: var(--line-height-relaxed);
}

.hero-actions {
  display: flex;
  gap: var(--spacing-md);
  justify-content: center;
  flex-wrap: wrap;
}

.hero-layout {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--spacing-4xl);
  align-items: center;
  min-height: 60vh;
}

.hero-image {
  position: relative;
}

.hero-image img {
  width: 100%;
  height: 400px;
  object-fit: cover;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-xl);
}

/* ========================================
   Buttons
   ======================================== */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-md) var(--spacing-xl);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-semibold);
  text-decoration: none;
  border-radius: var(--radius-lg);
  transition: all var(--transition-fast);
  cursor: pointer;
  border: 2px solid transparent;
  min-height: 48px;
}

.btn:focus {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

.btn-primary {
  background: var(--color-primary);
  color: white;
}

.btn-primary:hover {
  color: white;
  transform: translateY(-2px);
  box-shadow: 0 10px 25px rgba(37, 99, 235, 0.3);
}

.btn-secondary {
  background: var(--color-secondary);
  color: white;
}

.btn-secondary:hover {
  color: white;
  transform: translateY(-2px);
  box-shadow: 0 10px 25px rgba(16, 185, 129, 0.3);
}

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

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

.btn-white {
  background: white;
  color: var(--color-primary);
  box-shadow: var(--shadow-sm);
}

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

.btn-white-outline {
  background: transparent;
  color: white;
  border-color: white;
}

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

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

.services-overview {
  padding: var(--spacing-4xl) 0;
  background: var(--color-background);
}

.section-title {
  text-align: center;
  margin-bottom: var(--spacing-md);
}

.section-subtitle {
  text-align: center;
  font-size: var(--font-size-lg);
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-3xl);
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

.services-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--spacing-xl);
}

.service-card {
  background: var(--color-background);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  padding: var(--spacing-2xl);
  text-align: center;
  transition: all var(--transition-base);
  position: relative;
  overflow: hidden;
}

.service-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  background: linear-gradient(90deg, var(--color-primary) 0%, var(--color-secondary) 100%);
  transform: translateY(-100%);
  transition: transform var(--transition-base);
}

.service-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}

.service-card:hover::before {
  transform: translateY(0);
}

.service-icon {
  width: 80px;
  height: 80px;
  margin: 0 auto var(--spacing-lg);
  background: var(--color-background-alt);
  border-radius: var(--radius-full);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-primary);
}

.service-card h3 {
  font-size: var(--font-size-xl);
  margin-bottom: var(--spacing-md);
}

.service-card p {
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-lg);
}

.card-link {
  font-weight: var(--font-weight-semibold);
  color: var(--color-primary);
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-xs);
  transition: gap var(--transition-fast);
}

.card-link:hover {
  gap: var(--spacing-sm);
}

.card-link::after {
  content: '→';
  transition: transform var(--transition-fast);
}

.card-link:hover::after {
  transform: translateX(4px);
}

/* ========================================
   About Section
   ======================================== */

.about-home {
  padding: var(--spacing-4xl) 0;
  background: var(--color-background-alt);
}


.about-content {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--spacing-3xl);
  align-items: center;
}

.about-text h2 {
  margin-bottom: var(--spacing-lg);
}

.features-list {
  list-style: none;
  padding: 0;
  margin-bottom: var(--spacing-2xl);
}

.features-list li {
  padding: var(--spacing-sm) 0;
  padding-left: var(--spacing-xl);
  position: relative;
}

.features-list li::before {
  content: '✓';
  position: absolute;
  left: 0;
  color: var(--color-secondary);
  font-weight: var(--font-weight-bold);
}

.about-stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--spacing-lg);
}

.stat-card {
  background: var(--color-background);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--spacing-xl);
  text-align: center;
}

.stat-number {
  display: block;
  font-size: var(--font-size-3xl);
  font-weight: var(--font-weight-bold);
  color: var(--color-primary);
  margin-bottom: var(--spacing-sm);
}

.stat-label {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
}


/* ========================================
   Facility Section
   ======================================== */

.facility-section {
  padding: var(--spacing-4xl) 0;
  background: white;
}

.facility-layout {
  display: grid;
  grid-template-columns: 1fr 2fr;
  gap: var(--spacing-4xl);
  align-items: center;
}

.facility-image img {
  width: 100%;
  height: 400px;
  object-fit: cover;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
}

.facility-content h2 {
  margin-bottom: var(--spacing-lg);
}

.facility-content p {
  font-size: var(--font-size-lg);
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-lg);
  line-height: var(--line-height-relaxed);
}

.facility-features {
  list-style: none;
  margin-bottom: var(--spacing-xl);
}

.facility-features li {
  position: relative;
  padding-left: var(--spacing-lg);
  margin-bottom: var(--spacing-sm);
  color: var(--color-text-secondary);
}

.facility-features li::before {
  content: '✓';
  position: absolute;
  left: 0;
  color: var(--color-secondary);
  font-weight: var(--font-weight-bold);
}

/* ========================================
   CTA Section
   ======================================== */

.cta-section {
  padding: var(--spacing-4xl) 0;
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-dark) 100%);
  color: white;
  text-align: center;
}

.cta-section h2 {
  color: white;
  margin-bottom: var(--spacing-md);
}

.cta-section p {
  font-size: var(--font-size-lg);
  margin-bottom: var(--spacing-2xl);
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

.cta-actions {
  display: flex;
  gap: var(--spacing-md);
  justify-content: center;
  flex-wrap: wrap;
}

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

.site-footer {
  background: var(--color-text-primary);
  color: white;
  padding: var(--spacing-3xl) 0 var(--spacing-xl);
}

.footer-content {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: var(--spacing-2xl);
  margin-bottom: var(--spacing-2xl);
}

.footer-section h3 {
  color: white;
  font-size: var(--font-size-lg);
  margin-bottom: var(--spacing-md);
}

.footer-section p {
  color: rgba(255, 255, 255, 0.8);
  margin-bottom: var(--spacing-sm);
}

.footer-address {
  font-style: normal;
  line-height: var(--line-height-relaxed);
}

.footer-links {
  list-style: none;
  padding: 0;
}

.footer-links li {
  margin-bottom: var(--spacing-sm);
}

.footer-links a {
  color: rgba(255, 255, 255, 0.8);
}

.footer-links a:hover {
  color: white;
}

.contact-info {
  list-style: none;
  padding: 0;
}

.contact-info a {
  color: rgba(255, 255, 255, 0.8);
  text-decoration: underline;
}

.contact-info a:hover {
  color: white;
}

.footer-bottom {
  text-align: center;
  padding-top: var(--spacing-xl);
  border-top: 1px solid rgba(255, 255, 255, 0.2);
  color: rgba(255, 255, 255, 0.6);
}

/* ========================================
   Utility Classes
   ======================================== */

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