.topbar {
  background: #0d1b2a;
  font-size: 0.8rem;
}
.topbar-contact a,
.topbar-lang {
  color: #a0aec0;
  text-decoration: none;
  transition: color 0.2s;
}
.topbar-contact a:hover { color: #00b4d8; }

/* --- Navbar：viewport < 960px（约 50% 全高清宽度）显示 toggler --- */
@media (max-width: 560px) {
  #mainNav .navbar-toggler {
    display: flex !important;
  }
  #mainNav .navbar-collapse:not(.show):not(.collapsing) {
    display: none !important;
  }
  #mainNav .navbar-nav {
    flex-direction: column;
  }
}

/* --- Navbar --- */
#mainNav {
  transition: box-shadow 0.3s ease;
}
#mainNav.scrolled {
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.12) !important;
}
.navbar-brand {
  font-size: 1.4rem;
  letter-spacing: 1px;
}
.nav-link {
  font-size: 0.9rem;
  font-weight: 500;
  padding: 8px 14px !important;
  border-radius: 6px;
  transition: color 0.2s, background 0.2s;
}
.nav-link:hover,
.nav-link:focus {
  color: #0077b6 !important;
  background: rgba(0, 119, 182, 0.06);
}
.dropdown-item:active {
  background-color: #0077b6;
}

/* =============================================
   CONTENT AREA LAYOUT
   ============================================= */
.content-area {
  display: flex;
  min-height: calc(100vh - 100px);
  position: relative;
}

/* Sidebar */
.content-sidebar {
  width: 200px;
  flex-shrink: 0;
  background: #f4f8fb;
  border-right: 1px solid #e2e8f0;
  padding: 24px 12px;
  flex-direction: column;
}

.sidebar-nav {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.sidebar-link {
  display: flex;
  align-items: center;
  padding: 10px 14px;
  border-radius: 8px;
  color: #2d3748;
  font-size: 0.875rem;
  font-weight: 500;
  text-decoration: none;
  transition: background 0.2s, color 0.2s;
}
.sidebar-link:hover { background: #e8f4ff; color: #0077b6; }
.sidebar-link.active { background: #0077b6; color: #fff; }

/* iframe panel */
.content-frame-wrap {
  flex: 1;
  flex-direction: column;
  overflow: hidden;
}

.content-frame-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 20px;
  background: #fff;
  border-bottom: 1px solid #e2e8f0;
  font-weight: 600;
  font-size: 0.9rem;
  color: #0d1b2a;
}

.btn-close-frame {
  background: none;
  border: none;
  cursor: pointer;
  font-size: 1.1rem;
  color: #6b7280;
  padding: 4px 8px;
  border-radius: 4px;
  transition: color 0.2s, background 0.2s;
}
.btn-close-frame:hover { color: #0077b6; background: #e8f4ff; }

#contentFrame {
  flex: 1;
  width: 100%;
  height: calc(100vh - 150px);
  border: none;
}

/* Welcome panel */
.content-welcome { flex: 1; }