:root {
  --sidebar-bg: #0f172a;
  --sidebar-hover: #1e293b;
  --sidebar-active: #3b82f6;
  --bg-main: #f8fafc;
  --card-bg: #ffffff;
  --border-color: #e2e8f0;
  --text-main: #0f172a;
  --text-muted: #64748b;
}

body {
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  background-color: var(--bg-main);
  color: var(--text-main);
  margin: 0;
  padding: 0;
  min-height: 100vh;
  overflow-x: hidden;
}

/* LAYOUT WRAPPER */
.zentrum-wrapper {
  display: flex;
  min-height: 100vh;
  width: 100%;
  max-width: 100vw;
  overflow-x: hidden;
}

/* SIDEBAR */
.zentrum-sidebar {
  width: 260px;
  background-color: var(--sidebar-bg);
  color: #ffffff;
  flex-shrink: 0; /* Verhindert Quetschen der Sidebar */
  display: flex;
  flex-direction: column;
}

.zentrum-sidebar .brand-title {
  font-size: 1.35rem;
  font-weight: 700;
  color: #ffffff;
  text-decoration: none;
}

.zentrum-sidebar .nav-link {
  color: #94a3b8;
  font-weight: 500;
  border-radius: 8px;
  padding: 0.65rem 1rem;
  margin-bottom: 0.25rem;
  transition: all 0.2s ease;
}

.zentrum-sidebar .nav-link:hover {
  color: #ffffff;
  background-color: var(--sidebar-hover);
}

.zentrum-sidebar .nav-link.active {
  color: #ffffff;
  background-color: var(--sidebar-active);
}

.zentrum-sidebar .nav-link i {
  font-size: 1.1rem;
}

/* CONTENT BEREICH */
.zentrum-content {
  flex-grow: 1;
  display: flex;
  flex-direction: column;
  min-width: 0; /* Verhindert Flexbox-Overflow */
}

/* TOPBAR */
.zentrum-topbar {
  background-color: #ffffff;
  border-bottom: 1px solid var(--border-color);
  padding: 0.85rem 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

/* CARDS & KACHELN */
.stat-card {
  background: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 1.5rem;
  box-shadow: 0 1px 3px rgba(0,0,0,0.05);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.stat-card:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(0,0,0,0.05);
}

.stat-card .stat-icon {
  width: 48px;
  height: 48px;
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.35rem;
}

/* RESPONSIVE TOGGLE FOR MOBILE */
@media (max-width: 768px) {
  .zentrum-wrapper {
    flex-direction: column;
  }
  .zentrum-sidebar {
    width: 100%;
    min-height: auto;
  }
}