:root {
  --bg-color: #000000;
  --text-primary: #f8fafc;
  --text-secondary: #cbd5e1;
  --primary-color: #3b82f6;
  --primary-hover: #60a5fa;
  --glass-bg: rgba(15, 23, 42, 0.75);
  --glass-border: rgba(255, 255, 255, 0.1);
  --glass-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.37);
  --radius: 16px;
}

[data-theme='light'] {
  --text-primary: #0f172a;
  --text-secondary: #334155;
  --glass-bg: rgba(255, 255, 255, 0.85);
  --glass-border: rgba(0, 0, 0, 0.1);
}

* { box-sizing: border-box; margin: 0; padding: 0; }

body {
  font-family: 'Inter', sans-serif;
  background-color: var(--bg-color);
  color: var(--text-primary);
  overflow: hidden;
  height: 100vh;
  width: 100vw;
}

/* Full-Screen Background Image */
#background-image {
  position: absolute;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  object-fit: contain;
  z-index: 1;
  transition: opacity 0.5s ease-in-out;
  background-color: var(--bg-color);
}

/* Layout Overlay */
.layout {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 10;
  display: flex;
  pointer-events: none; /* Let clicks pass through empty space */
}

/* Glassmorphism Panel Base */
.glass-panel {
  background: var(--glass-bg);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid var(--glass-border);
  pointer-events: auto; /* Re-enable clicks */
}

/* Floating Menu Toggle Button */
.menu-toggle {
  position: absolute;
  top: 1.5rem;
  left: 1.5rem;
  z-index: 50;
  pointer-events: auto;
  
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.75rem 1.25rem;
  border-radius: 8px;
  font-weight: 600;
  cursor: pointer;
  border: 1px solid var(--glass-border);
  color: var(--text-primary);
  background: var(--glass-bg);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  box-shadow: var(--glass-shadow);
  transition: all 0.2s ease;
}

.menu-toggle svg {
  width: 20px;
  height: 20px;
}

.menu-toggle:hover {
  background: var(--primary-color);
  color: #fff;
  border-color: var(--primary-color);
  transform: translateY(-2px);
}

/* Sidebar (Left Overlay) */
.sidebar {
  position: absolute;
  top: 0;
  left: 0;
  width: 256px;
  height: 100%;
  display: flex;
  flex-direction: column;
  border-right: 1px solid var(--glass-border);
  transform: translateX(-100%);
  transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  z-index: 100;
}

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

.sidebar-header {
  padding: 1.5rem;
  border-bottom: 1px solid var(--glass-border);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.sidebar-header-actions {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.close-sidebar {
  background: none;
  border: none;
  color: var(--text-primary);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 0.25rem;
  border-radius: 4px;
  transition: all 0.2s ease;
}

.close-sidebar svg {
  width: 20px;
  height: 20px;
}

.close-sidebar:hover {
  color: var(--primary-color);
  background: rgba(255, 255, 255, 0.05);
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--primary-color);
}
.brand svg { width: 24px; height: 24px; }

.module-list {
  flex: 1;
  overflow-y: auto;
  padding: 1rem;
  list-style: none;
}

.module-item {
  padding: 0.75rem 1rem;
  margin-bottom: 0.5rem;
  border-radius: 8px;
  cursor: pointer;
  color: var(--text-secondary);
  font-weight: 500;
  transition: all 0.2s ease;
  font-size: 0.95rem;
}

.module-item:hover {
  background: rgba(255, 255, 255, 0.05);
}

.module-item.active {
  background-color: var(--primary-color);
  color: #fff;
}

/* Main Split Area */
.split-view {
  flex: 1;
  display: flex;
  justify-content: flex-end; /* Push panel to right */
  padding: 2rem;
  position: relative;
}

/* Right: Educational Floating Panel */
.edu-panel {
  width: 500px;
  height: 100%;
  border-radius: var(--radius);
  display: flex;
  flex-direction: column;
  box-shadow: var(--glass-shadow);
  overflow: hidden;
  transition: transform 0.4s cubic-bezier(0.4, 0, 0.2, 1), opacity 0.4s ease;
}

.edu-panel.minimized {
  transform: translateX(120%);
  opacity: 0;
  pointer-events: none;
}

/* Restore Button */
.restore-btn {
  position: absolute;
  bottom: 1.5rem;
  right: 1.5rem;
  z-index: 50;
  pointer-events: auto;
  
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.75rem 1.25rem;
  border-radius: 8px;
  font-weight: 600;
  cursor: pointer;
  border: 1px solid var(--glass-border);
  color: var(--text-primary);
  background: var(--glass-bg);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  box-shadow: var(--glass-shadow);
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  transform: translateY(150%);
  opacity: 0;
}

.restore-btn.visible {
  transform: translateY(0);
  opacity: 1;
}

.restore-btn svg {
  width: 20px;
  height: 20px;
}

.restore-btn:hover {
  background: var(--primary-color);
  color: #fff;
  border-color: var(--primary-color);
  transform: translateY(-2px);
}

.edu-header {
  padding: 2rem 2rem 1rem 2rem;
  border-bottom: 1px solid var(--glass-border);
}

.edu-header-main {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 0.5rem;
}

.edu-header h2 {
  font-size: 1.5rem;
  font-weight: 700;
  margin-bottom: 0;
}

.minimize-btn {
  background: none;
  border: none;
  color: var(--text-secondary);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 0.25rem;
  border-radius: 4px;
  transition: all 0.2s ease;
}

.minimize-btn svg {
  width: 20px;
  height: 20px;
}

.minimize-btn:hover {
  color: var(--primary-color);
  background: rgba(255, 255, 255, 0.05);
}

.edu-header p {
  color: var(--text-secondary);
  font-size: 0.95rem;
}

.edu-content {
  flex: 1;
  overflow-y: auto;
  padding: 1.5rem 2rem;
}

.step-card {
  display: none;
  animation: slideIn 0.3s ease;
}

.step-card.active {
  display: block;
}

.step-card h3 {
  color: var(--primary-color);
  font-size: 1.2rem;
  margin-bottom: 1.5rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.step-card p {
  line-height: 1.7;
  color: var(--text-primary);
  margin-bottom: 1.25rem;
}

.step-card ul {
  padding-left: 1.5rem;
  margin-bottom: 1.25rem;
  color: var(--text-primary);
  line-height: 1.7;
}

.step-card li { margin-bottom: 0.75rem; }

.step-card strong {
  font-weight: 700;
}

/* Controls */
.edu-controls {
  padding: 1.5rem 2rem;
  border-top: 1px solid var(--glass-border);
  display: flex;
  justify-content: space-between;
  align-items: center;
  background: rgba(0,0,0,0.1);
}

.btn {
  padding: 0.75rem 1.25rem;
  border-radius: 8px;
  font-weight: 600;
  cursor: pointer;
  border: none;
  transition: all 0.2s ease;
}

.btn-prev {
  background-color: transparent;
  border: 1px solid var(--glass-border);
  color: var(--text-primary);
}

.btn-prev:hover {
  background-color: rgba(255,255,255,0.1);
}

.btn-next {
  background-color: var(--primary-color);
  color: #fff;
}

.btn-next:hover {
  background-color: var(--primary-hover);
}
.btn:disabled {
  opacity: 0.3;
  cursor: not-allowed;
}

.step-indicator {
  font-size: 0.875rem;
  color: var(--text-secondary);
  font-weight: 500;
}

/* Animations */
@keyframes slideIn {
  from { opacity: 0; transform: translateY(10px); }
  to { opacity: 1; transform: translateY(0); }
}

/* Theme Toggle */
.theme-toggle {
  background: none;
  border: none;
  color: var(--text-primary);
  cursor: pointer;
}
.theme-toggle:hover { color: var(--primary-color); }

/* Responsive */
@media (max-width: 1024px) {
  .layout { flex-direction: column; overflow: hidden; padding: 0; }
  .sidebar {
    width: 280px;
    height: 100%;
    flex-direction: column;
    align-items: stretch;
    border-right: 1px solid var(--glass-border);
    border-bottom: none;
    transform: translateX(-100%);
    position: absolute;
    top: 0;
    left: 0;
    z-index: 100;
  }
  .sidebar.open {
    transform: translateX(0);
  }
  .sidebar-header {
    border-bottom: 1px solid var(--glass-border);
    padding: 1.5rem;
  }
  .module-list {
    display: block;
    overflow-y: auto;
    margin-left: 0;
    white-space: normal;
    padding: 1rem;
  }
  .module-item {
    margin-bottom: 0.5rem;
    margin-right: 0;
  }
  .split-view { padding: 1rem; flex-direction: column; justify-content: flex-end; }
  .edu-panel {
    width: 100%;
    height: 60vh;
    margin-top: auto;
    border-radius: var(--radius);
    transition: transform 0.4s cubic-bezier(0.4, 0, 0.2, 1), opacity 0.4s ease;
  }
  .edu-panel.minimized {
    transform: translateY(120%);
    opacity: 0;
  }
  .menu-toggle {
    top: 1rem;
    left: 1rem;
    padding: 0.5rem 1rem;
    font-size: 0.9rem;
  }
  .restore-btn {
    bottom: 1rem;
    right: 1rem;
    padding: 0.5rem 1rem;
    font-size: 0.9rem;
  }
}