/* ===== CodeLearn — Liquid Glass UI ===== */

/* === CSS Variables === */
:root {
  /* Spacing */
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2rem;
  --spacing-2xl: 3rem;
  
  /* Border radius */
  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
  --radius-full: 9999px;
  
  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-base: 250ms ease;
  --transition-slow: 350ms ease;
  
  /* Z-index layers */
  --z-base: 1;
  --z-dropdown: 100;
  --z-sticky: 200;
  --z-fixed: 300;
  --z-modal-backdrop: 400;
  --z-modal: 500;
  --z-toast: 600;
  --z-tooltip: 700;
}

/* Light theme */
[data-theme="light"] {
  --bg-primary: #f0f2f7;
  --bg-secondary: #ffffff;
  --bg-tertiary: #e2e6ef;
  --text-primary: #0f172a;
  --text-secondary: #334155;
  --text-tertiary: #64748b;
  --border-color: rgba(0, 0, 0, 0.12);
  --glass-bg: rgba(255, 255, 255, 0.85);
  --glass-border: rgba(0, 0, 0, 0.08);
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.08);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 30px rgba(0, 0, 0, 0.12);
  --overlay-bg: rgba(0, 0, 0, 0.4);
}

/* Dark theme */
[data-theme="dark"] {
  --bg-primary: #0f1419;
  --bg-secondary: #1a1f2e;
  --bg-tertiary: #252b3b;
  --text-primary: #f7fafc;
  --text-secondary: #cbd5e0;
  --text-tertiary: #a0aec0;
  --border-color: rgba(255, 255, 255, 0.1);
  --glass-bg: rgba(26, 31, 46, 0.7);
  --glass-border: rgba(255, 255, 255, 0.1);
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.5);
  --overlay-bg: rgba(0, 0, 0, 0.7);
}

/* Accent colors */
[data-accent="indigo"] {
  --accent-primary: #667eea;
  --accent-secondary: #764ba2;
  --accent-light: #a78bfa;
  --accent-dark: #5a67d8;
}

[data-accent="emerald"] {
  --accent-primary: #10b981;
  --accent-secondary: #059669;
  --accent-light: #34d399;
  --accent-dark: #047857;
}

[data-accent="rose"] {
  --accent-primary: #f43f5e;
  --accent-secondary: #e11d48;
  --accent-light: #fb7185;
  --accent-dark: #be123c;
}

[data-accent="amber"] {
  --accent-primary: #f59e0b;
  --accent-secondary: #d97706;
  --accent-light: #fbbf24;
  --accent-dark: #b45309;
}

/* === Base Styles === */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  overflow-x: hidden;
}

/* === Glass Panel Effect === */
.glass-panel {
  background: var(--glass-bg);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
}

/* Light mode glass panels need a visible border */
[data-theme="light"] .glass-panel {
  border-color: rgba(0, 0, 0, 0.1);
  box-shadow: 0 2px 12px rgba(0, 0, 0, 0.08), 0 0 0 1px rgba(0,0,0,0.04);
}

[data-theme="light"] .card {
  border-color: rgba(0, 0, 0, 0.08);
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
}

[data-theme="light"] .navbar {
  border-bottom: 1px solid rgba(0,0,0,0.08);
  box-shadow: 0 1px 8px rgba(0,0,0,0.06);
}

[data-theme="light"] .btn-secondary {
  background: #e8ecf4;
  color: #0f172a;
  border: 1px solid rgba(0,0,0,0.1);
}

[data-theme="light"] .btn-secondary:hover:not(:disabled) {
  background: #dde2ec;
}

[data-theme="light"] textarea,
[data-theme="light"] input[type="text"],
[data-theme="light"] input[type="search"],
[data-theme="light"] select {
  background: #f8fafc;
  color: #0f172a;
  border-color: rgba(0,0,0,0.15);
}

[data-theme="light"] pre,
[data-theme="light"] code {
  background: #f1f5f9;
  color: #0f172a;
}

/* === Navigation Bar === */
.navbar {
  position: sticky;
  top: 0;
  z-index: var(--z-sticky);
  display: flex;
  align-items: center;
  gap: var(--spacing-lg);
  padding: var(--spacing-md) var(--spacing-xl);
  margin-bottom: var(--spacing-lg);
}

.nav-brand {
  display: flex;
  align-items: center;
}

.brand-link {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  text-decoration: none;
  color: var(--text-primary);
  font-weight: 700;
  font-size: 1.25rem;
  transition: transform var(--transition-fast);
}

.brand-link:hover {
  transform: scale(1.05);
}

.brand-icon {
  font-size: 1.5rem;
}

.nav-links {
  display: flex;
  gap: var(--spacing-md);
  flex: 1;
}

.nav-link {
  padding: var(--spacing-sm) var(--spacing-md);
  text-decoration: none;
  color: var(--text-secondary);
  font-weight: 500;
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
}

.nav-link:hover, .nav-link.active {
  color: var(--accent-primary);
  background: var(--bg-tertiary);
}

.nav-stats {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
}

.stat-hearts, .stat-streak, .stat-xp, .stat-level {
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
  padding: var(--spacing-xs) var(--spacing-sm);
  background: var(--bg-tertiary);
  border-radius: var(--radius-full);
  font-weight: 600;
  font-size: 0.875rem;
}

.hearts-display {
  font-size: 1rem;
}

.level-badge {
  background: linear-gradient(135deg, var(--accent-primary), var(--accent-secondary));
  color: white;
  padding: var(--spacing-xs) var(--spacing-sm);
  border-radius: var(--radius-full);
  font-weight: 700;
  font-size: 0.75rem;
}

.nav-actions {
  display: flex;
  gap: var(--spacing-sm);
}

.nav-icon-btn {
  background: transparent;
  border: none;
  font-size: 1.25rem;
  cursor: pointer;
  padding: var(--spacing-sm);
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
  color: var(--text-primary);
  text-decoration: none;
  display: flex;
  align-items: center;
  justify-content: center;
}

.nav-icon-btn:hover {
  background: var(--bg-tertiary);
  transform: scale(1.1);
}

.nav-hamburger {
  display: none;
  background: transparent;
  border: none;
  font-size: 1.5rem;
  cursor: pointer;
  color: var(--text-primary);
}

/* Mobile menu */
.mobile-menu {
  position: fixed;
  top: 70px;
  right: var(--spacing-md);
  width: 250px;
  padding: var(--spacing-md);
  z-index: var(--z-dropdown);
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
}

.mobile-menu.hidden {
  display: none;
}

.mobile-nav-link {
  padding: var(--spacing-md);
  text-decoration: none;
  color: var(--text-primary);
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
  font-weight: 500;
}

.mobile-nav-link:hover {
  background: var(--bg-tertiary);
  color: var(--accent-primary);
}

/* === Main Content === */
#main-content {
  max-width: 1400px;
  margin: 0 auto;
  padding: var(--spacing-xl);
  min-height: calc(100vh - 100px);
}

/* === Buttons === */
.btn {
  padding: var(--spacing-sm) var(--spacing-lg);
  border: none;
  border-radius: var(--radius-md);
  font-weight: 600;
  font-size: 1rem;
  cursor: pointer;
  transition: all var(--transition-fast);
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-sm);
}

.btn-primary {
  background: linear-gradient(135deg, var(--accent-primary), var(--accent-secondary));
  color: white;
  box-shadow: var(--shadow-sm);
}

.btn-primary:hover:not(:disabled) {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.btn-secondary {
  background: var(--bg-tertiary);
  color: var(--text-primary);
}

.btn-secondary:hover:not(:disabled) {
  background: var(--bg-secondary);
}

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.btn-icon {
  padding: var(--spacing-sm);
  aspect-ratio: 1;
}

/* === Cards === */
.card {
  background: var(--glass-bg);
  backdrop-filter: blur(12px);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-lg);
  padding: var(--spacing-lg);
  box-shadow: var(--shadow-md);
  transition: all var(--transition-base);
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}

.card-title {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: var(--spacing-sm);
  color: var(--text-primary);
}

.card-description {
  color: var(--text-secondary);
  margin-bottom: var(--spacing-md);
}

/* === Grid Layouts === */
.grid {
  display: grid;
  gap: var(--spacing-lg);
}

.grid-2 {
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
}

.grid-3 {
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
}

.grid-4 {
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
}

/* === VFX Layer === */
#vfx-layer {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  z-index: var(--z-modal);
}

.particle {
  position: absolute;
  pointer-events: none;
  font-size: 1.5rem;
}

.floating-xp {
  position: absolute;
  font-weight: 700;
  font-size: 1.5rem;
  color: var(--accent-primary);
  pointer-events: none;
  animation: floatUp 1s ease-out forwards;
}

@keyframes floatUp {
  from {
    opacity: 1;
    transform: translateY(0);
  }
  to {
    opacity: 0;
    transform: translateY(-100px);
  }
}

@keyframes floatUpBig {
  from {
    opacity: 1;
    transform: translateY(0) scale(1);
  }
  50% {
    opacity: 1;
    transform: translateY(-50px) scale(1.2);
  }
  to {
    opacity: 0;
    transform: translateY(-150px) scale(0.8);
  }
}

.screen-shake {
  animation: shake 0.5s ease-in-out;
}

@keyframes shake {
  0%, 100% { transform: translateX(0); }
  10%, 30%, 50%, 70%, 90% { transform: translateX(-10px); }
  20%, 40%, 60%, 80% { transform: translateX(10px); }
}

/* === Level Up Overlay === */
.levelup-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: var(--overlay-bg);
  backdrop-filter: blur(8px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: var(--z-modal);
  animation: fadeIn var(--transition-base);
}

.levelup-overlay.hidden {
  display: none;
}

@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

/* === Toast Notifications === */
#toast-container {
  position: fixed;
  top: 80px;
  right: var(--spacing-lg);
  z-index: var(--z-toast);
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
}

.toast {
  background: var(--glass-bg);
  backdrop-filter: blur(12px);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);
  padding: var(--spacing-md);
  box-shadow: var(--shadow-lg);
  min-width: 250px;
  animation: slideInRight var(--transition-base);
}

@keyframes slideInRight {
  from {
    transform: translateX(400px);
    opacity: 0;
  }
  to {
    transform: translateX(0);
    opacity: 1;
  }
}

.toast.success {
  border-left: 4px solid #10b981;
}

.toast.error {
  border-left: 4px solid #ef4444;
}

.toast.info {
  border-left: 4px solid #3b82f6;
}

/* === Badge Notification === */
.badge-notification {
  position: fixed;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  background: var(--glass-bg);
  backdrop-filter: blur(12px);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-xl);
  padding: var(--spacing-2xl);
  box-shadow: var(--shadow-lg);
  z-index: var(--z-modal);
  text-align: center;
  animation: scaleIn var(--transition-slow);
}

.badge-notification.hidden {
  display: none;
}

@keyframes scaleIn {
  from {
    transform: translate(-50%, -50%) scale(0.5);
    opacity: 0;
  }
  to {
    transform: translate(-50%, -50%) scale(1);
    opacity: 1;
  }
}

/* === Shortcut Overlay === */
.shortcut-overlay {
  position: fixed;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  padding: var(--spacing-2xl);
  z-index: var(--z-modal);
  max-width: 500px;
  width: 90%;
}

.shortcut-overlay.hidden {
  display: none;
}

.shortcut-overlay h2 {
  margin-bottom: var(--spacing-lg);
}

.shortcut-overlay ul {
  list-style: none;
  margin-bottom: var(--spacing-lg);
}

.shortcut-overlay li {
  padding: var(--spacing-sm) 0;
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
}

kbd {
  background: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: var(--spacing-xs) var(--spacing-sm);
  font-family: monospace;
  font-size: 0.875rem;
  font-weight: 600;
}

/* === Utility Classes === */
.hidden {
  display: none !important;
}

.text-center {
  text-align: center;
}

.mt-1 { margin-top: var(--spacing-sm); }
.mt-2 { margin-top: var(--spacing-md); }
.mt-3 { margin-top: var(--spacing-lg); }
.mt-4 { margin-top: var(--spacing-xl); }

.mb-1 { margin-bottom: var(--spacing-sm); }
.mb-2 { margin-bottom: var(--spacing-md); }
.mb-3 { margin-bottom: var(--spacing-lg); }
.mb-4 { margin-bottom: var(--spacing-xl); }

/* === Responsive Design === */
@media (max-width: 768px) {
  .nav-links {
    display: none;
  }
  
  .nav-hamburger {
    display: block;
  }
  
  .nav-stats {
    gap: var(--spacing-sm);
  }
  
  .stat-hearts, .stat-streak, .stat-xp {
    font-size: 0.75rem;
  }
  
  #main-content {
    padding: var(--spacing-md);
  }
  
  .grid-2, .grid-3, .grid-4 {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 480px) {
  .navbar {
    padding: var(--spacing-sm) var(--spacing-md);
  }
  
  .brand-name {
    display: none;
  }
  
  .nav-stats .stat-level {
    display: none;
  }
}

/* === Accessibility === */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border-width: 0;
}

:focus-visible {
  outline: 2px solid var(--accent-primary);
  outline-offset: 2px;
}

/* === Code Editor Styles === */
.editor-container {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  overflow: hidden;
}

.editor-toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--spacing-sm) var(--spacing-md);
  background: var(--bg-tertiary);
  border-bottom: 1px solid var(--border-color);
}

.editor-actions {
  display: flex;
  gap: var(--spacing-sm);
}

/* === Progress Bar === */
.progress-bar {
  width: 100%;
  height: 8px;
  background: var(--bg-tertiary);
  border-radius: var(--radius-full);
  overflow: hidden;
}

.progress-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--accent-primary), var(--accent-secondary));
  transition: width var(--transition-base);
}

/* === Loading Spinner === */
.spinner {
  border: 3px solid var(--bg-tertiary);
  border-top: 3px solid var(--accent-primary);
  border-radius: 50%;
  width: 40px;
  height: 40px;
  animation: spin 1s linear infinite;
}

@keyframes spin {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}