html, body {
  min-height: 100%;
  background: #f4f6fb;
  color: #172033;
}

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

.sidebar {
  width: 260px;
  background: #111827;
  color: white;
  padding: 24px 18px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  margin-bottom: 28px;
}

.brand-mark {
  display: inline-flex;
  width: 44px;
  height: 44px;
  align-items: center;
  justify-content: center;
  border-radius: 14px;
  background: #2563eb;
}

.nav-menu {
  display: grid;
  gap: 8px;
}

.nav-link {
  color: #d1d5db;
  border-radius: 12px;
  padding: 10px 12px;
  text-decoration: none;
}

.nav-link:hover,
.nav-link.active {
  background: rgba(255, 255, 255, 0.12);
  color: white;
}

.content {
  flex: 1;
  display: flex;
  flex-direction: column;
}

.topbar {
  height: 64px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 28px;
  background: white;
  border-bottom: 1px solid #e5e7eb;
}

.content-body {
  padding: 28px;
}

.page-card {
  background: white;
  border: 1px solid #e5e7eb;
  border-radius: 18px;
  padding: 24px;
  box-shadow: 0 10px 30px rgba(15, 23, 42, 0.06);
}

.page-header {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  margin-bottom: 24px;
}

.page-header h1 {
  margin: 0;
}

.page-header p {
  margin: 6px 0 0;
  color: #6b7280;
}

.metric-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 16px;
}

.metric-card {
  border: 1px solid #e5e7eb;
  border-radius: 16px;
  padding: 18px;
  background: #f9fafb;
}

.metric-card span {
  display: block;
  color: #6b7280;
  margin-bottom: 8px;
}

.metric-card strong {
  font-size: 28px;
}

.form-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 16px;
  align-items: end;
}

.form-actions {
  display: flex;
  align-items: end;
}

.validation-message {
  color: #dc2626;
  font-size: 12px;
  margin-top: 4px;
}

@media (max-width: 900px) {
  .app-shell {
    display: block;
  }

  .sidebar {
    width: auto;
  }

  .metric-grid,
  .form-grid {
    grid-template-columns: 1fr;
  }
}