:root {
  /* Цветовая палитра */
  --color-bg-light: #f8f9fa;
  --color-bg-dark: #212529;
  --color-primary: #0d6efd;
  --color-secondary: #6c757d;
  --color-accent: #343a40;
  --color-white: #ffffff;
  --spacing-xs: 0.5rem;
  --spacing-sm: 1rem;
  --spacing-md: 1.5rem;
  --spacing-lg: 2rem;
  --border-radius: 0.75rem;
  --transition-fast: 0.2s ease;
}

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

body {
  font-family: 'Helvetica Neue', Arial, sans-serif;
  background-color: var(--color-bg-light);
  color: var(--color-secondary);
  line-height: 1.8;
  font-size: 1rem;
  width: 100%;
  overflow-x: hidden;
}

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

a:hover {
  color: darken(var(--color-primary), 10%);
}

header {
  background: linear-gradient(180deg, var(--color-accent), var(--color-bg-dark));
  color: var(--color-white);
  text-align: center;
  padding: var(--spacing-lg) 0;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
}

header h1 {
  font-size: clamp(2rem, 5vw, 3rem);
  margin-bottom: var(--spacing-sm);
}

header .lead {
  font-size: clamp(1rem, 2.5vw, 1.25rem);
}

.navbar {
  background-color: var(--color-white);
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

.navbar-nav .nav-link {
  font-size: 1rem;
  padding: var(--spacing-xs) var(--spacing-sm);
  transition: color var(--transition-fast), transform var(--transition-fast);
}

.navbar-nav .nav-link:hover {
  color: var(--color-primary) !important;
  transform: translateY(-2px);
}

main {
  max-width: 1200px;
  margin: 0 auto;
  padding: var(--spacing-lg) var(--spacing-sm);
}

section {
  margin-bottom: var(--spacing-lg);
  animation: fadeIn var(--transition-fast);
}

section h2 {
  font-size: clamp(1.5rem, 4vw, 2rem);
  text-align: center;
  margin-bottom: var(--spacing-md);
  position: relative;
}

section h2 i {
  margin-right: var(--spacing-xs);
  color: var(--color-primary);
}

.card {
  background-color: var(--color-white);
  border: none;
  border-radius: var(--border-radius);
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
  transition: transform var(--transition-fast), box-shadow var(--transition-fast);
}

.card:hover {
  transform: translateY(-5px);
  box-shadow: 0 6px 20px rgba(0, 0, 0, 0.1);
}

.card-body {
  padding: var(--spacing-md);
}

.btn {
  border-radius: var(--border-radius);
  padding: var(--spacing-sm) var(--spacing-md);
  font-weight: 600;
  transition: transform var(--transition-fast), opacity var(--transition-fast);
}

.btn-primary {
  background-color: var(--color-primary);
  border: none;
}

.btn-success {
  background-color: #28a745;
  border: none;
}

.btn-info {
  background-color: #17a2b8;
  border: none;
}

.btn-primary:hover,
.btn-success:hover,
.btn-info:hover {
  opacity: 0.9;
  transform: scale(1.05);
}

ul.list-group-flush .list-group-item {
  background: var(--color-white);
  border-left: 4px solid var(--color-primary);
  margin-bottom: var(--spacing-sm);
  border-radius: var(--border-radius);
  padding: var(--spacing-sm) var(--spacing-md);
}

.text-muted {
  font-size: 0.95rem;
  color: var(--color-secondary);
}

footer {
  background: linear-gradient(180deg, var(--color-bg-dark), var(--color-accent));
  color: var(--color-white);
  text-align: center;
  padding: var(--spacing-md) var(--spacing-sm);
  font-size: 0.9rem;
}

@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* Responsive Media Queries */
@media (max-width: 992px) {
  .navbar-nav .nav-link {
    font-size: 0.95rem;
  }
  header h1 {
    font-size: clamp(1.75rem, 6vw, 2.5rem);
  }
}

@media (max-width: 768px) {
  main {
    padding: var(--spacing-md) var(--spacing-xs);
  }
  .card-body {
    padding: var(--spacing-sm);
  }
  .btn {
    padding: var(--spacing-xs) var(--spacing-sm);
    font-size: 0.9rem;
  }
}

@media (max-width: 576px) {
  header .btn {
    display: block;
    width: 80%;
    margin: var(--spacing-xs) auto;
  }
  nav {
    padding: var(--spacing-xs) 0;
  }
}