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

body {
  font-family: 'Segoe UI', sans-serif;
  background-color: #fff;
  color: #000;
}
header {
  background-color: #9e1b1b;
  color: white;
  padding: 20px;
  text-align: center;
  position: sticky;
  top: 0;
  z-index: 1000;
  transition: background-color 0.3s ease;
}

/* Класс, добавляемый при прокрутке */
header.transparent {
  background-color: rgba(158, 27, 27, 0.85);
  backdrop-filter: blur(4px);
}

.container {
  display: flex;
  min-height: 80vh;
}

.sidebar {
  width: 250px;
  background-color: #f9f9f9;
  padding: 20px;
  border-right: 1px solid #ccc;
}

.sidebar ul {
  list-style: none;
}

.sidebar a {
  display: block;
  padding: 10px;
  color: #000;
  text-decoration: none;
  border-left: 4px solid transparent;
  transition: all 0.3s ease;
}

.sidebar a:hover {
  background-color: #9e1b1b;
  color: #fff;
  border-left: 4px solid #660000;
}

.content {
  flex-grow: 1;
  padding: 30px;
}

footer {
  background-color: #9e1b1b;
  color: white;
  text-align: center;
  padding: 15px;
}

@media (max-width: 768px) {
  .container {
    flex-direction: column;
  }

  .sidebar {
    width: 100%;
    border-right: none;
    border-bottom: 1px solid #ccc;
  }
}