/* Sidebar & Topbar Drawer Navigation System */
:root {
  --sidebar-width: 270px;
  --topbar-height: 60px;
}

body {
  padding-top: var(--topbar-height);
  transition: padding-left 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

body.sidebar-open {
  padding-left: var(--sidebar-width);
}

/* Topbar */
.topbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--topbar-height);
  background: rgba(15, 23, 42, 0.95);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-color);
  z-index: 900;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 1.5rem;
  transition: left 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

body.sidebar-open .topbar {
  left: var(--sidebar-width);
}

.topbar-left {
  display: flex;
  align-items: center;
  gap: 1.25rem;
}

.sidebar-toggle-btn {
  background: rgba(30, 41, 59, 0.8);
  border: 1px solid var(--border-color);
  color: var(--text-bright);
  width: 40px;
  height: 40px;
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  font-size: 1.1rem;
  transition: all 0.2s ease;
}

.sidebar-toggle-btn:hover {
  background: rgba(59, 130, 246, 0.15);
  border-color: var(--accent);
  color: var(--accent);
  box-shadow: 0 0 12px var(--accent-glow);
}

.current-page-title {
  font-size: 1.2rem;
  font-weight: 600;
  color: var(--text-bright);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.topbar-right {
  display: flex;
  align-items: center;
  gap: 1rem;
}

/* Sidebar Drawer */
.sidebar {
  position: fixed;
  top: 0;
  left: 0;
  width: var(--sidebar-width);
  height: 100vh;
  background: rgba(15, 23, 42, 0.98);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-right: 1px solid var(--border-color);
  z-index: 1000;
  transform: translateX(-100%);
  transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  display: flex;
  flex-direction: column;
  box-shadow: 4px 0 24px rgba(0, 0, 0, 0.5);
}

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

.sidebar-header {
  padding: 1.25rem 1.25rem 1rem 1.25rem;
  border-bottom: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.sidebar-brand {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  text-decoration: none;
  color: var(--text-bright);
  font-weight: 700;
  font-size: 1.15rem;
}

.sidebar-close-btn {
  background: transparent;
  border: none;
  color: var(--text-muted);
  cursor: pointer;
  font-size: 1.1rem;
  padding: 0.25rem 0.5rem;
  border-radius: 6px;
  transition: all 0.2s;
}

.sidebar-close-btn:hover {
  color: var(--text-bright);
  background: rgba(255, 255, 255, 0.1);
}

.sidebar-section {
  padding: 1rem 1.25rem 0.75rem 1.25rem;
  border-bottom: 1px solid var(--border-color);
}

.sidebar-menu {
  flex: 1;
  overflow-y: auto;
  padding: 0.75rem 0.75rem;
}

.sidebar-nav-item {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.7rem 1rem;
  border-radius: 8px;
  color: var(--text-muted);
  font-weight: 500;
  font-size: 0.95rem;
  cursor: pointer;
  transition: all 0.2s ease;
  margin-bottom: 0.35rem;
  text-decoration: none;
}

.sidebar-nav-item:hover {
  background: rgba(255, 255, 255, 0.07);
  color: var(--text-bright);
}

.sidebar-nav-item.is-active {
  background: var(--accent) !important;
  color: #ffffff !important;
  box-shadow: 0 4px 14px var(--accent-glow);
  font-weight: 600;
}

.sidebar-nav-item .icon {
  font-size: 1.1rem;
  width: 1.5rem;
  text-align: center;
}

.sidebar-footer {
  padding: 1rem 1.25rem;
  border-top: 1px solid var(--border-color);
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  background: rgba(15, 23, 42, 0.6);
}

/* Mobile Backdrop Overlay */
.sidebar-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.6);
  backdrop-filter: blur(2px);
  z-index: 950;
  opacity: 0;
  visibility: hidden;
  transition: all 0.3s ease;
}

body.sidebar-open .sidebar-overlay {
  opacity: 1;
  visibility: visible;
}

@media (max-width: 1023px) {
  body.sidebar-open {
    padding-left: 0;
  }
  body.sidebar-open .topbar {
    left: 0;
  }
}