:root {
  --primary-color: #6366f1;
  --secondary-color: #8b5cf6;
  --bg-gradient: linear-gradient(135deg, #f3f4f6 0%, #e5e7eb 100%);
  --surface-bg: rgba(255, 255, 255, 0.7);
  --surface-border: rgba(255, 255, 255, 0.4);
  --text-primary: #1f2937;
  --text-secondary: #4b5563;
  --input-bg: rgba(255, 255, 255, 0.9);
  --glass-shadow: 0 8px 32px 0 rgba(31, 38, 135, 0.1);
  --sidebar-width: 250px;
  --transition: all 0.3s ease;
}

[data-theme="dark"] {
  --primary-color: #818cf8;
  --secondary-color: #a78bfa;
  --bg-gradient: linear-gradient(135deg, #111827 0%, #1f2937 100%);
  --surface-bg: rgba(31, 41, 55, 0.6);
  --surface-border: rgba(75, 85, 99, 0.4);
  --text-primary: #f9fafb;
  --text-secondary: #d1d5db;
  --input-bg: rgba(55, 65, 81, 0.8);
  --glass-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.3);
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  background: var(--bg-gradient);
  color: var(--text-primary);
  min-height: 100vh;
  margin: 0;
  padding: 0;
  overflow-x: hidden;
  transition: var(--transition);
}

/* Glassmorphism Utilities */
.glass-panel {
  background: var(--surface-bg);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid var(--surface-border);
  border-radius: 1rem;
  box-shadow: var(--glass-shadow);
}

/* Sidebar Layout */
.app-container {
  display: flex;
  min-height: 100vh;
}

.sidebar {
  width: var(--sidebar-width);
  flex-shrink: 0;
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  gap: 1rem;
  z-index: 100;
  border-right: 1px solid var(--surface-border);
}

.sidebar .brand {
  font-size: 1.5rem;
  font-weight: 700;
  background: linear-gradient(to right, var(--primary-color), var(--secondary-color));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  margin-bottom: 2rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.nav-link {
  color: var(--text-secondary);
  font-weight: 500;
  padding: 0.75rem 1rem;
  border-radius: 0.5rem;
  transition: var(--transition);
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.nav-link:hover, .nav-link.active {
  background: rgba(99, 102, 241, 0.1);
  color: var(--primary-color);
}

.main-content {
  flex-grow: 1;
  padding: 2rem;
  overflow-y: auto;
  height: 100vh;
}

/* UI Elements */
.form-control, .form-select {
  background-color: var(--input-bg);
  border: 1px solid var(--surface-border);
  color: var(--text-primary);
  border-radius: 0.5rem;
  padding: 0.75rem 1rem;
}

.form-control:focus, .form-select:focus {
  background-color: var(--input-bg);
  color: var(--text-primary);
  border-color: var(--primary-color);
  box-shadow: 0 0 0 0.25rem rgba(99, 102, 241, 0.25);
}

.btn-primary {
  background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
  border: none;
  border-radius: 0.5rem;
  padding: 0.75rem 1.5rem;
  font-weight: 600;
  transition: var(--transition);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 15px rgba(99, 102, 241, 0.4);
}

.btn-outline {
  border: 1px solid var(--primary-color);
  color: var(--primary-color);
  background: transparent;
  border-radius: 0.5rem;
  padding: 0.75rem 1.5rem;
  font-weight: 600;
  transition: var(--transition);
}

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

.qr-preview-container {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 2rem;
  min-height: 400px;
}

#qr-canvas {
  background: #fff;
  padding: 1rem;
  border-radius: 1rem;
  box-shadow: 0 10px 25px rgba(0,0,0,0.1);
  transition: var(--transition);
}

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

.fade-in {
  animation: fadeIn 0.4s ease-out forwards;
}

/* Responsive */
@media (max-width: 768px) {
  .app-container {
    flex-direction: column;
  }
  .sidebar {
    width: 100%;
    border-right: none;
    border-bottom: 1px solid var(--surface-border);
    padding: 1rem;
    height: auto;
    flex-direction: row;
    overflow-x: auto;
    align-items: center;
  }
  .sidebar .brand {
    margin-bottom: 0;
    margin-right: 1rem;
  }
  .main-content {
    padding: 1rem;
    height: auto;
  }
}

/* Color Pickers */
input[type="color"] {
  -webkit-appearance: none;
  border: none;
  width: 100%;
  height: 40px;
  border-radius: 0.5rem;
  cursor: pointer;
  padding: 0;
  background: none;
}
input[type="color"]::-webkit-color-swatch-wrapper { padding: 0; }
input[type="color"]::-webkit-color-swatch { border: 1px solid var(--surface-border); border-radius: 0.5rem; }

/* Drag and Drop Zone */
.drop-zone {
  border: 2px dashed var(--primary-color);
  border-radius: 1rem;
  padding: 2rem;
  text-align: center;
  cursor: pointer;
  transition: var(--transition);
  background: rgba(99, 102, 241, 0.05);
}
.drop-zone.dragover {
  background: rgba(99, 102, 241, 0.15);
  border-color: var(--secondary-color);
}
.drop-zone img {
  max-width: 100px;
  max-height: 100px;
  margin-top: 1rem;
  border-radius: 0.5rem;
}

/* Scrollbar */
::-webkit-scrollbar {
  width: 8px;
  height: 8px;
}
::-webkit-scrollbar-track {
  background: var(--surface-bg);
}
::-webkit-scrollbar-thumb {
  background: var(--primary-color);
  border-radius: 4px;
}