:root {
  color-scheme: light dark;
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  line-height: 1.5;
  font-size: 16px;
  background: #f4f5f7;
  color: #1a1d23;
}

body {
  margin: 0;
  min-height: 100vh;
}

.app-shell {
  display: flex;
  min-height: 100vh;
}

.sidebar {
  width: 260px;
  padding: 32px 24px;
  background: linear-gradient(160deg, #0d47a1, #1976d2);
  color: #fff;
  display: flex;
  flex-direction: column;
}

.sidebar__title {
  font-size: 1.5rem;
  margin: 0 0 24px;
}

.sidebar__nav {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.nav-link {
  padding: 12px 16px;
  border-radius: 12px;
  text-decoration: none;
  color: inherit;
  background: rgba(255, 255, 255, 0.12);
  transition: background 0.2s ease, transform 0.2s ease;
}

.nav-link:hover {
  background: rgba(255, 255, 255, 0.2);
  transform: translateX(4px);
}

.nav-link.active {
  background: #fff;
  color: #0d47a1;
  font-weight: 600;
}

.content {
  flex: 1;
  padding: 48px;
  background: #f7f9fc;
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.content__section {
  display: none;
  max-width: 720px;
}

.content__section.active {
  display: block;
}

.content__section h2 {
  margin-top: 0;
  color: #0d47a1;
}

.content__section p {
  margin-bottom: 0;
  color: #3b4353;
}

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

  .sidebar {
    width: 100%;
    flex-direction: row;
    gap: 12px;
    align-items: center;
  }

  .sidebar__nav {
    flex-direction: row;
    gap: 12px;
  }

  .content {
    padding: 24px;
  }
}