:root {
  --sidebar-width: 260px;
  --sidebar-collapsed-width: 70px;
  --sidebar-bg: #1e293b;
  --sidebar-hover: #334155;
  --sidebar-active: #3b82f6;
  --sidebar-text: #e2e8f0;
  --sidebar-muted: #94a3b8;
  --transition: 0.3s ease;
}

body {
  margin: 0;
  padding-left: var(--sidebar-width);
  transition: padding-left var(--transition);
}

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

.sidebar {
  position: fixed;
  top: 0;
  left: 0;
  width: var(--sidebar-width);
  height: 100vh;
  background: var(--sidebar-bg);
  color: var(--sidebar-text);
  transition: width var(--transition);
  overflow-x: hidden;
  overflow-y: auto;
  z-index: 1000;
}

.sidebar.collapsed {
  width: var(--sidebar-collapsed-width);
}

.sidebar-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px;
  border-bottom: 1px solid #334155;
  height: 60px;
}

.logo-text {
  font-weight: 600;
  font-size: 18px;
  white-space: nowrap;
}

.sidebar.collapsed .logo-text {
  display: none;
}

.btn-close-sidebar {
  background: none;
  border: none;
  color: var(--sidebar-muted);
  font-size: 24px;
  cursor: pointer;
  display: none;
}

.menu-list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.menu-item {
  position: relative;
}

.menu-link {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px 16px;
  color: var(--sidebar-text);
  text-decoration: none;
  transition: background 0.2s;
  white-space: nowrap;
}

.menu-link:hover {
  background: var(--sidebar-hover);
}

.menu-link.active {
  background: var(--sidebar-active);
  color: #fff;
}

.menu-link i {
  font-size: 18px;
  min-width: 20px;
}

.sidebar.collapsed .menu-link span,
.sidebar.collapsed .arrow {
  display: none;
}

.has-submenu .arrow {
  margin-left: auto;
  transition: transform 0.3s;
}

.has-submenu.open .arrow {
  transform: rotate(180deg);
}

.submenu {
  list-style: none;
  padding: 0;
  margin: 0;
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease;
  background: #0f172a;
}

.has-submenu.open .submenu {
  max-height: 500px;
}

.submenu li a {
  display: block;
  padding: 10px 16px 10px 48px;
  color: var(--sidebar-muted);
  text-decoration: none;
  font-size: 14px;
}

.submenu li a:hover,
.submenu li a.active {
  color: #fff;
  background: var(--sidebar-hover);
}

.sidebar.collapsed .submenu {
  display: none;
}

/* Mobile */
.sidebar-overlay {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0,0,0,0.5);
  z-index: 999;
}

.btn-sidebar-open {
  display: none;
  position: fixed;
  top: 10px;
  left: 10px;
  z-index: 998;
  background: var(--sidebar-bg);
  color: #fff;
  border: none;
  padding: 8px 12px;
  border-radius: 6px;
  cursor: pointer;
}

@media (max-width: 768px) {
  body {
    padding-left: 0;
  }
  .sidebar {
    transform: translateX(-100%);
    width: var(--sidebar-width);
  }
  .sidebar.show {
    transform: translateX(0);
  }
  .sidebar.collapsed {
    width: var(--sidebar-width);
  }
  .btn-close-sidebar,
  .btn-sidebar-open {
    display: block;
  }
  .sidebar-overlay.show {
    display: block;
  }
}