.app {
  display: flex;
  height: 100vh;
  overflow: hidden;
  position: relative;
}

.sidebar {
  display: flex;
  flex-direction: column;
  width: 18rem;
  min-width: 18rem;
  height: 100vh;
  background: var(--bg-sidebar);
  color: var(--text-sidebar);
  border-right: 1px solid var(--border-sidebar);
  flex-shrink: 0;
  overflow-y: auto;
  overflow-x: hidden;
  z-index: var(--z-sidebar);
  transition: background var(--transition-base), color var(--transition-base), border-color var(--transition-base);
}

.sidebar-header {
  padding: var(--space-lg) var(--space-md);
  border-bottom: 1px solid var(--border-sidebar);
}

.sidebar-logo {
  font-size: 1rem;
  font-weight: 700;
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  color: #fff;
}

.sidebar-logo svg {
  flex-shrink: 0;
}

.sidebar-nav {
  flex: 1;
  padding: var(--space-md);
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
}

.nav-item {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  padding: var(--space-sm) var(--space-md);
  border: none;
  background: transparent;
  color: var(--text-sidebar);
  font-family: var(--font-family);
  font-size: 0.875rem;
  font-weight: 500;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all var(--transition-fast);
  text-align: left;
  width: 100%;
}

.nav-item:hover {
  background: var(--bg-sidebar-hover);
  color: var(--color-sidebar-accent);
}

.nav-item.active {
  background: var(--color-sidebar-active-bg);
  color: #fff;
  font-weight: 600;
}

.sidebar-footer {
  padding: var(--space-md);
  border-top: 1px solid var(--border-sidebar);
}

.sidebar-version {
  font-size: 0.6875rem;
  color: var(--text-sidebar);
  opacity: 0.4;
  text-align: center;
  margin-top: var(--space-sm);
}

.theme-toggle {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-sm) var(--space-md);
  border: none;
  background: transparent;
  color: var(--text-sidebar);
  font-family: var(--font-family);
  font-size: 0.875rem;
  font-weight: 500;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all var(--transition-fast);
  width: 100%;
  opacity: 0.75;
}

.theme-toggle:hover {
  opacity: 1;
  background: var(--bg-sidebar-hover);
}

.mobile-toggle {
  display: none;
  position: fixed;
  top: var(--space-md);
  left: var(--space-md);
  z-index: calc(var(--z-sidebar) + 1);
  width: 2.5rem;
  height: 2.5rem;
  border: 1px solid var(--border-main);
  border-radius: var(--radius-md);
  background: var(--bg-main);
  color: var(--text-main);
  cursor: pointer;
  align-items: center;
  justify-content: center;
}

.main {
  flex: 1;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  min-width: 0;
}

.header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-md) var(--space-xl);
  border-bottom: 1px solid var(--border-main);
  background: var(--bg-header);
  flex-shrink: 0;
  transition: background var(--transition-base);
}

.header-title {
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--text-header);
}

.header-actions {
  display: flex;
  align-items: center;
  gap: var(--space-md);
}

.header-time {
  font-size: 0.75rem;
  color: var(--text-muted);
  font-family: var(--font-mono);
  font-weight: 400;
  opacity: 0.7;
}

.content {
  flex: 1;
  overflow-y: auto;
  overflow-x: hidden;
  padding: var(--space-xl);
  background: var(--bg-content);
}

.view {
  display: none;
  animation: fadeIn var(--transition-base) ease;
}

.view.active {
  display: block;
}

@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(var(--space-sm));
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.5);
  z-index: var(--z-overlay);
  cursor: pointer;
}

.loader-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.3);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: var(--z-loader);
}

@media (max-width: 1023px) {
  .content {
    padding: var(--space-lg);
  }

  .header {
    padding: var(--space-md) var(--space-lg);
  }
}

@media (max-width: 768px) {
  .mobile-toggle {
    display: flex;
  }

  .sidebar {
    position: fixed;
    top: 0;
    left: 0;
    transform: translateX(-100%);
    transition: transform var(--transition-base);
    box-shadow: var(--shadow-xl);
  }

  .sidebar.open {
    transform: translateX(0);
  }

  .overlay.active {
    display: block;
  }

  .content {
    padding: var(--space-md);
  }

  .header {
    padding-left: 4.5rem;
  }
}