/* ============================================
   Vokabel Master+ - Styles
   Mobile-First PWA für Vokabellernen
   ============================================ */

/* CSS Custom Properties (Design Tokens) */
:root {
  /* Light Mode Colors */
  --color-bg: #f8fafc;
  --color-bg-secondary: #ffffff;
  --color-bg-tertiary: #f1f5f9;
  --color-text: #0f172a;
  --color-text-secondary: #475569;
  --color-text-muted: #94a3b8;
  --color-border: #e2e8f0;
  --color-primary: #06b6d4;
  --color-primary-hover: #0891b2;
  --color-primary-dark: #0e7490;
  --color-primary-light: #cffafe;
  --color-success: #10b981;
  --color-success-light: #d1fae5;
  --color-error: #ef4444;
  --color-error-light: #fee2e2;
  --color-warning: #f59e0b;
  --color-warning-light: #fef3c7;

  /* Spacing */
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;

  /* Typography */
  --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
  --font-size-xs: 0.75rem;
  --font-size-sm: 0.875rem;
  --font-size-base: 1rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.25rem;
  --font-size-2xl: 1.5rem;
  --font-size-3xl: 2rem;

  /* Borders & Shadows */
  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
  --radius-full: 9999px;
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.07);
  --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.1);

  /* Layout */
  --nav-height: 64px;
  --header-height: 56px;
  --safe-area-bottom: env(safe-area-inset-bottom, 0px);
}

/* Dark Mode */
[data-theme="dark"] {
  --color-bg: #0f172a;
  --color-bg-secondary: #1e293b;
  --color-bg-tertiary: #334155;
  --color-text: #f8fafc;
  --color-text-secondary: #cbd5e1;
  --color-text-muted: #64748b;
  --color-border: #334155;
  --color-primary-light: #164e63;
  --color-success-light: #064e3b;
  --color-error-light: #7f1d1d;
  --color-warning-light: #78350f;
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.2);
  --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.4);
}

/* Base Reset */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
  -webkit-tap-highlight-color: transparent;
}

body {
  font-family: var(--font-family);
  font-size: var(--font-size-base);
  line-height: 1.5;
  color: var(--color-text);
  background-color: var(--color-bg);
  min-height: 100vh;
  min-height: 100dvh;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* Prevent horizontal scroll */
html,
body {
  max-width: 100vw;
  overflow-x: hidden;
}

/* Prevent double-tap zoom on iOS without blocking accessibility */
* {
  touch-action: manipulation;
}

/* Text Overflow Prevention */
.vocab-item-native,
.vocab-item-foreign,
.flashcard-content,
.mc-option,
.settings-item-label,
.settings-item-desc,
h1,
h2,
h3,
h4,
p {
  overflow-wrap: break-word;
  word-wrap: break-word;
  word-break: break-word;
  hyphens: auto;
}

/* Dynamic Font Sizing */
.flashcard-content {
  font-size: clamp(1rem, 4vw, 1.5rem);
}

.vocab-item-native,
.vocab-item-foreign {
  font-size: clamp(0.875rem, 3.5vw, 1rem);
}

.mc-option {
  font-size: clamp(0.875rem, 3vw, 1rem);
}

/* Text Overflow Ellipsis */
.vocab-item-content {
  min-width: 0;
  /* Enable text-overflow in flexbox */
}

.vocab-item-native,
.vocab-item-foreign {
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

/* Allow wrap on card views */
.flashcard-content {
  white-space: normal;
}

/* App Container */
.app-container {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  min-height: 100dvh;
  width: 100%;
  max-width: 100vw;
}

/* Header */
.app-header {
  position: sticky;
  top: 0;
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--header-height);
  padding: 0 var(--space-md);
  background-color: var(--color-bg-secondary);
  border-bottom: 1px solid var(--color-border);
}

.app-header h1 {
  font-size: var(--font-size-lg);
  font-weight: 600;
  display: flex;
  align-items: center;
  box-shadow: var(--shadow-sm);
}

.header-actions {
  display: flex;
  gap: var(--space-sm);
}

.btn-sm {
  padding: var(--space-xs) var(--space-sm);
  font-size: var(--font-size-sm);
  gap: var(--space-xs);
}

#install-button.show {
  display: inline-flex;
  align-items: center;
  animation: fadeIn 0.3s ease;
}

/* Main Content Area */
.app-main {
  flex: 1;
  padding: var(--space-md) var(--space-lg);
  padding-bottom: calc(var(--nav-height) + var(--space-md) + var(--safe-area-bottom));
  overflow-y: auto;
  overflow-x: hidden;
  width: 100%;
}

/* Views (Pages) */
.view {
  display: none;
  width: 100%;
  max-width: 600px;
  margin: 0 auto;
}

.view.active {
  display: block;
  animation: fadeIn 0.2s ease-out;
}

@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(8px);
  }

  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* Bottom Navigation */
.bottom-nav {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  z-index: 100;
  display: flex;
  justify-content: space-around;
  align-items: stretch;
  height: var(--nav-height);
  padding-bottom: var(--safe-area-bottom);
  background-color: var(--color-bg-secondary);
  border-top: 1px solid var(--color-border);
}

.nav-item {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: var(--space-xs);
  padding: var(--space-sm);
  color: var(--color-text-muted);
  text-decoration: none;
  font-size: var(--font-size-sm);
  background: none;
  border: none;
  cursor: pointer;
  transition: color 0.2s ease, transform 0.2s ease;
  min-height: 44px;
  min-width: 44px;
}

.nav-item:hover,
.nav-item:focus {
  color: var(--color-primary);
  transform: scale(1.05);
}

.nav-item.active {
  color: var(--color-primary);
  transform: scale(1);
}

.nav-item svg {
  width: 24px;
  height: 24px;
}

.nav-item span {
  font-size: 0.75rem;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  padding: var(--space-sm) var(--space-md);
  font-size: var(--font-size-base);
  font-weight: 500;
  text-decoration: none;
  border: none;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all 0.2s ease;
  transform: translateY(0);
  min-height: 44px;
  min-width: 44px;
}

.btn:hover:not(:disabled) {
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(6, 182, 212, 0.3);
}

.btn:active:not(:disabled) {
  transform: translateY(0);
  box-shadow: 0 2px 4px rgba(6, 182, 212, 0.2);
}

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

.btn-primary {
  background-color: var(--color-primary);
  color: white;
}

.btn-primary:hover:not(:disabled) {
  background-color: var(--color-primary-hover);
  box-shadow: 0 4px 12px rgba(6, 182, 212, 0.4);
}

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

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

.btn-success {
  background-color: var(--color-success);
  color: white;
}

.btn-error {
  background-color: var(--color-error);
  color: white;
}

.btn-ghost {
  background: transparent;
  color: var(--color-text-secondary);
}

.btn-ghost:hover:not(:disabled) {
  background-color: var(--color-bg-tertiary);
}

.btn-icon {
  padding: var(--space-sm);
  border-radius: var(--radius-full);
}

.btn-lg {
  padding: var(--space-md) var(--space-lg);
  font-size: var(--font-size-lg);
}

.btn-block {
  display: flex;
  width: 100%;
}

/* Forms */
.form-group {
  margin-bottom: var(--space-md);
}

.form-label {
  display: block;
  margin-bottom: var(--space-xs);
  font-size: var(--font-size-sm);
  font-weight: 500;
  color: var(--color-text-secondary);
}

.form-input {
  width: 100%;
  padding: var(--space-sm) var(--space-md);
  font-size: var(--font-size-base);
  font-family: inherit;
  color: var(--color-text);
  background-color: var(--color-bg-secondary);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  transition: border-color 0.2s, box-shadow 0.2s;
  min-height: 44px;
}

.form-input:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(6, 182, 212, 0.15);
}

.form-input::placeholder {
  color: var(--color-text-muted);
}

textarea.form-input {
  resize: vertical;
  min-height: 80px;
}

select.form-input {
  cursor: pointer;
  -webkit-appearance: none;
  -moz-appearance: none;
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='24' height='24' viewBox='0 0 24 24' fill='none' stroke='%2394a3b8' stroke-width='2'%3E%3Cpath d='M6 9l6 6 6-6'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right var(--space-sm) center;
  background-size: 20px;
  padding-right: 36px;
}

/* Cards */
.card {
  background-color: var(--color-bg-secondary);
  border-radius: var(--radius-lg);
  border: 1px solid var(--color-border);
  overflow: hidden;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: 0 8px 25px rgba(0, 0, 0, 0.1);
}

[data-theme="dark"] .card:hover {
  box-shadow: 0 8px 25px rgba(0, 0, 0, 0.3);
}

.card-body {
  padding: var(--space-md) var(--space-lg);
}

.card-header {
  padding: var(--space-md);
  border-bottom: 1px solid var(--color-border);
  font-weight: 600;
}

/* Stats Cards */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-md);
  margin-bottom: var(--space-lg);
}

.stat-card {
  background: var(--color-bg-secondary);
  border-radius: var(--radius-lg);
  padding: var(--space-md);
  border: 1px solid var(--color-border);
}

.stat-value {
  font-size: var(--font-size-2xl);
  font-weight: 700;
  color: var(--color-primary);
}

.stat-label {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
}

/* Vocabulary List */
.vocab-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
}

.vocab-item {
  position: relative;
  display: flex;
  align-items: center;
  gap: var(--space-md);
  padding: var(--space-md);
  background-color: var(--color-bg-secondary);
  border-radius: var(--radius-lg);
  border: none;
  cursor: pointer;
  z-index: 1;
}

/* Uiverse.io gradient border effect */
.vocab-item::before {
  content: '';
  position: absolute;
  inset: -2px;
  border-radius: calc(var(--radius-lg) + 2px);
  background: linear-gradient(-45deg, var(--color-primary) 0%, #8b5cf6 50%, #ec4899 100%);
  z-index: -2;
  opacity: 0;
  transition: opacity 0.4s ease, transform 0.6s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

.vocab-item::after {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: var(--radius-lg);
  background: var(--color-bg-secondary);
  z-index: -1;
}

.vocab-item:hover::before {
  opacity: 1;
  transform: rotate(-2deg) scale(1.02);
}

.vocab-item:hover {
  transform: translateY(-3px);
  box-shadow: 0 10px 30px rgba(6, 182, 212, 0.15), 0 5px 15px rgba(139, 92, 246, 0.1);
}

.vocab-item-content {
  flex: 1;
  min-width: 0;
  padding: var(--space-xs) 0;
}

.vocab-item-native {
  font-weight: 700;
  font-size: var(--font-size-base);
  color: var(--color-text);
  word-break: break-word;
  line-height: 1.4;
}

.vocab-item-foreign {
  font-size: var(--font-size-sm);
  color: var(--color-primary);
  word-break: break-word;
  margin-top: 0.25rem;
  font-weight: 500;
}

.vocab-item-meta {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-size: 0.7rem;
  color: var(--color-text-muted);
  margin-top: var(--space-sm);
  padding-top: var(--space-sm);
  border-top: 1px solid var(--color-border);
}

.vocab-item-actions {
  display: flex;
  gap: var(--space-xs);
}

/* Flashcard */
.flashcard-container {
  perspective: 1000px;
  width: 100%;
  aspect-ratio: 3/2;
  max-height: 300px;
  margin-bottom: var(--space-lg);
}

.flashcard {
  position: relative;
  width: 100%;
  height: 100%;
  cursor: pointer;
  transform-style: preserve-3d;
  transition: transform 0.5s, box-shadow 0.2s ease;
}

.flashcard:hover {
  box-shadow: 0 8px 30px rgba(6, 182, 212, 0.15);
}

.flashcard.flipped {
  transform: rotateY(180deg);
}

.flashcard-face {
  position: absolute;
  width: 100%;
  height: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: var(--space-lg);
  background-color: var(--color-bg-secondary);
  border-radius: var(--radius-xl);
  border: 2px solid var(--color-border);
  backface-visibility: hidden;
  text-align: center;
}

.flashcard-back {
  transform: rotateY(180deg);
  background-color: var(--color-primary-light);
}

.flashcard-word {
  font-size: var(--font-size-2xl);
  font-weight: 700;
  word-break: break-word;
}

.flashcard-hint {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  margin-top: var(--space-sm);
}

.flashcard-answer-label,
.flashcard-example-label {
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: var(--space-xs);
}

.flashcard-example-label {
  margin-top: var(--space-lg);
}

.flashcard-example {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  font-style: italic;
}

.flashcard-example .highlight {
  color: var(--color-primary);
  font-weight: 700;
  text-decoration: underline;
  text-decoration-color: var(--color-primary-light);
  text-underline-offset: 2px;
}

.flashcard-example-translation {
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
  margin-top: var(--space-xs);
}

/* Verstanden Button */
.understood-btn-wrapper {
  display: flex;
  justify-content: center;
  margin-top: var(--space-lg);
}

.flashcard-action-buttons {
  display: flex;
  gap: var(--space-md);
  justify-content: center;
  align-items: stretch;
  margin-top: var(--space-lg);
  padding: 0 var(--space-md);
}

.understood-btn {
  cursor: pointer;
  border: none;
  background: var(--color-primary);
  color: #fff;
  width: 100px;
  height: 100px;
  border-radius: 50%;
  overflow: hidden;
  position: relative;
  display: grid;
  place-content: center;
  transition: background 300ms, transform 200ms;
  font-weight: 600;
}

.understood-btn__text {
  position: absolute;
  inset: 0;
  animation: text-rotation 8s linear infinite;
}

.understood-btn__text>span {
  position: absolute;
  transform: rotate(calc(18deg * var(--index)));
  inset: 7px;
  font-size: 11px;
  font-weight: 700;
}

.understood-btn__circle {
  position: relative;
  width: 40px;
  height: 40px;
  overflow: hidden;
  background: #fff;
  color: var(--color-primary);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
}

.understood-btn__icon--copy {
  position: absolute;
  transform: translate(-150%, 150%);
}

.understood-btn:hover {
  background: var(--color-primary-dark, #0e7490);
  transform: scale(1.05);
}

.understood-btn:hover .understood-btn__icon:first-child {
  transition: transform 0.3s ease-in-out;
  transform: translate(150%, -150%);
}

.understood-btn:hover .understood-btn__icon--copy {
  transition: transform 0.3s ease-in-out 0.1s;
  transform: translate(0);
}

@keyframes text-rotation {
  to {
    rotate: 360deg;
  }
}

/* Multiple Choice */
.mc-options {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

.mc-option {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  padding: var(--space-md);
  background-color: var(--color-bg-secondary);
  border: 2px solid var(--color-border);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all 0.2s;
  text-align: left;
  font-size: var(--font-size-base);
  min-height: 52px;
}

.mc-option:hover:not(:disabled) {
  border-color: var(--color-primary);
  background-color: var(--color-primary-light);
}

.mc-option.correct {
  border-color: var(--color-success);
  background-color: var(--color-success-light);
}

.mc-option.incorrect {
  border-color: var(--color-error);
  background-color: var(--color-error-light);
}

.mc-option:disabled {
  cursor: default;
}

/* Typing Exercise */
.typing-question {
  font-size: var(--font-size-xl);
  font-weight: 600;
  text-align: center;
  padding: var(--space-lg);
  background-color: var(--color-bg-secondary);
  border-radius: var(--radius-lg);
  margin-bottom: var(--space-lg);
}

.typing-input-wrapper {
  position: relative;
  margin-bottom: var(--space-md);
}

.typing-input {
  width: 100%;
  padding: var(--space-md);
  font-size: var(--font-size-lg);
  text-align: center;
}

.typing-feedback {
  text-align: center;
  padding: var(--space-md);
  border-radius: var(--radius-md);
  margin-top: var(--space-md);
  font-weight: 500;
}

.typing-feedback.correct {
  background-color: var(--color-success-light);
  color: var(--color-success);
}

.typing-feedback.incorrect {
  background-color: var(--color-error-light);
  color: var(--color-error);
}

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

.progress-fill {
  height: 100%;
  background-color: var(--color-primary);
  border-radius: var(--radius-full);
  transition: width 0.3s ease;
}

/* Session Info */
.session-info {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  margin-bottom: var(--space-sm);
}

/* Action Buttons Row */
.action-row {
  display: flex;
  gap: var(--space-md);
  margin-top: var(--space-lg);
}

.action-row .btn {
  flex: 1;
}

/* Empty State */
.empty-state {
  text-align: center;
  padding: var(--space-2xl) var(--space-md);
  color: var(--color-text-secondary);
}

.empty-state svg {
  width: 64px;
  height: 64px;
  margin-bottom: var(--space-md);
  opacity: 0.5;
}

.empty-state h3 {
  margin-bottom: var(--space-sm);
  color: var(--color-text);
}

/* Modal/Dialog */
.modal-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background-color: rgba(0, 0, 0, 0.5);
  z-index: 200;
  overflow-y: auto;
  -webkit-overflow-scrolling: touch;
  padding: var(--space-md);
  padding-bottom: calc(var(--space-md) + var(--safe-area-bottom));
}

.modal-overlay.active {
  display: flex;
  flex-direction: column;
  align-items: center;
}

.modal {
  width: 100%;
  max-width: 500px;
  margin: auto;
  flex-shrink: 0;
  overflow-y: visible;
  background-color: var(--color-bg-secondary);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-lg);
}

.modal-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-md);
  border-bottom: 1px solid var(--color-border);
}

.modal-header h2 {
  font-size: var(--font-size-lg);
}

.modal-body {
  padding: var(--space-md);
}

.modal-footer {
  display: flex;
  gap: var(--space-sm);
  justify-content: flex-end;
  padding: var(--space-md);
  border-top: 1px solid var(--color-border);
}

/* Settings */
.settings-section {
  margin-bottom: var(--space-xl);
}

.settings-section h3 {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  margin-bottom: var(--space-md);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  font-weight: 600;
  padding-left: var(--space-sm);
}

.settings-item {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-md) var(--space-lg);
  background-color: var(--color-bg-secondary);
  border-radius: var(--radius-lg);
  margin-bottom: var(--space-md);
  border: none;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.settings-item::before {
  content: '';
  position: absolute;
  inset: -1px;
  border-radius: calc(var(--radius-lg) + 1px);
  background: linear-gradient(135deg, var(--color-border), transparent);
  z-index: -1;
  opacity: 0.5;
}

.settings-item:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

[data-theme="dark"] .settings-item:hover {
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
}

.settings-item-label {
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: 0.125rem;
}

.settings-item-desc {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
}

/* Toggle Switch */
/* Uiverse.io Toggle Switch */
.toggle {
  position: relative;
  width: 60px;
  height: 32px;
  flex-shrink: 0;
}

.toggle input {
  opacity: 0;
  width: 0;
  height: 0;
  position: absolute;
}

.toggle-slider {
  position: absolute;
  cursor: pointer;
  inset: 0;
  background: #252532;
  border-radius: 165px;
  box-shadow: inset 0px 4px 8px 0px #16151c, 0px 2px 4px -1px #403f4e;
  border: 1px solid #32303e;
  transition: all 0.3s ease;
}

.toggle-slider::before {
  position: absolute;
  content: "";
  height: 24px;
  width: 24px;
  left: 4px;
  top: 50%;
  transform: translateY(-50%);
  background: linear-gradient(180deg, #3b3a4e 0%, #272733 100%);
  border-radius: 50%;
  box-shadow: inset 0px 4px 3px 0px #424151, 0px 3px 10px 0px #0f0e17;
  transition: all 0.3s ease;
}

/* Indicator dot */
.toggle-slider::after {
  content: '';
  position: absolute;
  width: 10px;
  height: 10px;
  border: 2px solid #ef565f;
  border-radius: 50%;
  right: 10px;
  top: 50%;
  transform: translateY(-50%);
  transition: all 0.3s ease;
}

.toggle input:checked+.toggle-slider {
  background: linear-gradient(135deg, #164e63 0%, #0e7490 100%);
  border-color: var(--color-primary);
}

.toggle input:checked+.toggle-slider::before {
  left: calc(100% - 28px);
  background: linear-gradient(180deg, var(--color-primary) 0%, #0891b2 100%);
  box-shadow: 0 0 15px rgba(6, 182, 212, 0.5), inset 0px 4px 3px 0px rgba(255, 255, 255, 0.2);
}

.toggle input:checked+.toggle-slider::after {
  border-color: #60d480;
  left: 10px;
  right: auto;
}

.toggle input:focus+.toggle-slider {
  box-shadow: inset 0px 4px 8px 0px #16151c, 0px 2px 4px -1px #403f4e, 0 0 0 3px rgba(6, 182, 212, 0.3);
}

/* Light mode toggle adjustments */
:root:not([data-theme="dark"]) .toggle-slider {
  background: #e2e8f0;
  box-shadow: inset 0px 2px 4px 0px rgba(0, 0, 0, 0.1), 0px 1px 2px 0px rgba(0, 0, 0, 0.05);
  border-color: #cbd5e1;
}

:root:not([data-theme="dark"]) .toggle-slider::before {
  background: linear-gradient(180deg, #ffffff 0%, #f1f5f9 100%);
  box-shadow: 0px 2px 4px rgba(0, 0, 0, 0.1);
}

:root:not([data-theme="dark"]) .toggle input:checked+.toggle-slider {
  background: linear-gradient(135deg, var(--color-primary) 0%, #0891b2 100%);
}

/* Badge */
.badge {
  display: inline-flex;
  align-items: center;
  padding: 2px 8px;
  font-size: 0.75rem;
  font-weight: 500;
  border-radius: var(--radius-full);
  background-color: var(--color-primary-light);
  color: var(--color-primary);
}

.badge-success {
  background-color: var(--color-success-light);
  color: var(--color-success);
}

.badge-warning {
  background-color: var(--color-warning-light);
  color: var(--color-warning);
}

.badge-error {
  background-color: var(--color-error-light);
  color: var(--color-error);
}

/* Streak Display */
.streak-display {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-md);
  background: linear-gradient(135deg, var(--color-warning) 0%, #f97316 100%);
  color: white;
  border-radius: var(--radius-lg);
  margin-bottom: var(--space-lg);
}

.streak-display svg {
  width: 32px;
  height: 32px;
}

.streak-value {
  font-size: var(--font-size-2xl);
  font-weight: 700;
}

.streak-label {
  font-size: var(--font-size-sm);
  opacity: 0.9;
}

/* Learning Mode Selector */
.mode-selector {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-md);
  margin-bottom: var(--space-lg);
}

.mode-card {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-lg);
  background-color: var(--color-bg-secondary);
  border: 2px solid var(--color-border);
  border-radius: var(--radius-lg);
  cursor: pointer;
  transition: all 0.2s;
  text-align: center;
}

.mode-card:hover {
  border-color: var(--color-primary);
  transform: translateY(-2px);
}

.mode-card.active {
  border-color: var(--color-primary);
  background-color: var(--color-primary-light);
}

.mode-card svg {
  width: 32px;
  height: 32px;
  color: var(--color-primary);
}

.mode-card-title {
  font-weight: 600;
}

.mode-card-desc {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
}

/* Session Mode Buttons */
.session-modes {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
  margin-bottom: var(--space-lg);
}

.session-mode-btn {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-md);
  background-color: var(--color-bg-secondary);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all 0.2s;
}

.session-mode-btn:hover {
  border-color: var(--color-primary);
}

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

.session-mode-info {
  display: flex;
  align-items: center;
  gap: var(--space-md);
}

.session-mode-info svg {
  width: 24px;
  height: 24px;
  color: var(--color-primary);
}

.session-mode-title {
  font-weight: 600;
}

.session-mode-count {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
}

/* Dictation Mode */
.dictation-controls {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-md);
  margin-bottom: var(--space-lg);
}

.speak-btn {
  width: 80px;
  height: 80px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--color-primary) 0%, #8b5cf6 100%);
  color: white;
  border: none;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--shadow-lg);
  transition: transform 0.2s;
}

.speak-btn:hover {
  transform: scale(1.05);
}

.speak-btn:active {
  transform: scale(0.95);
}

.speak-btn svg {
  width: 40px;
  height: 40px;
}

/* Search Input */
.search-wrapper {
  position: relative;
  margin-bottom: var(--space-md);
}

.search-wrapper svg {
  position: absolute;
  left: var(--space-md);
  top: 50%;
  transform: translateY(-50%);
  width: 20px;
  height: 20px;
  color: var(--color-text-muted);
}

.search-input {
  padding-left: 44px;
}

/* Filter Chips */
.category-filter-panel {
  margin-bottom: var(--space-md);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  background: var(--color-bg-secondary);
  overflow: hidden;
}

.category-filter-panel summary {
  cursor: pointer;
  list-style: none;
  padding: var(--space-sm) var(--space-md);
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  font-weight: 600;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.category-filter-panel summary::-webkit-details-marker {
  display: none;
}

.category-filter-panel summary::after {
  content: '';
  width: 0.5rem;
  height: 0.5rem;
  border-right: 2px solid var(--color-text-muted);
  border-bottom: 2px solid var(--color-text-muted);
  transform: rotate(45deg);
  transition: transform 0.2s ease;
  margin-left: var(--space-sm);
}

.category-filter-panel[open] summary {
  border-bottom: 1px solid var(--color-border);
}

.category-filter-panel[open] summary::after {
  transform: rotate(225deg);
}

.category-filter-panel .filter-chips {
  padding: var(--space-sm);
  margin-bottom: 0;
}

.filter-chips {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
  margin-bottom: var(--space-md);
}

.filter-chip {
  padding: var(--space-xs) var(--space-md);
  font-size: var(--font-size-sm);
  background-color: var(--color-bg-tertiary);
  color: var(--color-text-secondary);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-full);
  cursor: pointer;
  transition: all 0.2s;
}

.filter-chip:hover {
  border-color: var(--color-primary);
}

.filter-chip.active {
  background-color: var(--color-primary);
  color: white;
  border-color: var(--color-primary);
}

/* Difficulty Indicator */
.difficulty {
  display: flex;
  gap: 2px;
}

.difficulty-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background-color: var(--color-border);
}

.difficulty-dot.filled {
  background-color: var(--color-primary);
}

.difficulty--easy .difficulty-dot.filled {
  background-color: var(--color-success);
}

.difficulty--medium .difficulty-dot.filled {
  background-color: #3b82f6;
}

.difficulty--hard .difficulty-dot.filled {
  background-color: var(--color-error);
}

/* Toast Notifications */
.toast-container {
  position: fixed;
  bottom: calc(var(--nav-height) + var(--space-md) + var(--safe-area-bottom));
  left: var(--space-md);
  right: var(--space-md);
  z-index: 300;
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
  pointer-events: none;
}

.toast {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-md);
  background-color: var(--color-bg-secondary);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg);
  border: 1px solid var(--color-border);
  animation: slideUp 0.3s ease-out;
  pointer-events: auto;
}

.toast.success {
  border-left: 4px solid var(--color-success);
}

.toast.error {
  border-left: 4px solid var(--color-error);
}

.toast.info {
  border-left: 4px solid var(--color-primary);
}

@keyframes slideUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }

  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* Utility Classes */
.text-center {
  text-align: center;
}

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

.text-muted {
  color: var(--color-text-muted);
}

.text-success {
  color: var(--color-success);
}

.text-error {
  color: var(--color-error);
}

.font-bold {
  font-weight: 700;
}

.mt-sm {
  margin-top: var(--space-sm);
}

.mt-md {
  margin-top: var(--space-md);
}

.mt-lg {
  margin-top: var(--space-lg);
}

.mb-sm {
  margin-bottom: var(--space-sm);
}

.mb-md {
  margin-bottom: var(--space-md);
}

.mb-lg {
  margin-bottom: var(--space-lg);
}

.hidden {
  display: none !important;
}

/* File Input Styling */
.file-input-wrapper {
  position: relative;
}

.file-input {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  border: 0;
}

/* Results Summary */
.results-summary {
  text-align: center;
  padding: var(--space-xl);
}

.results-score {
  font-size: var(--font-size-3xl);
  font-weight: 700;
  color: var(--color-primary);
  margin-bottom: var(--space-sm);
}

.results-message {
  font-size: var(--font-size-lg);
  color: var(--color-text-secondary);
  margin-bottom: var(--space-lg);
}

.results-details {
  display: flex;
  justify-content: center;
  gap: var(--space-xl);
  margin-bottom: var(--space-lg);
}

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

.results-detail-value {
  font-size: var(--font-size-xl);
  font-weight: 600;
}

.results-detail-label {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
}

/* Word Selection Checkbox */
.vocab-checkbox {
  display: flex;
  align-items: center;
  margin-right: var(--space-sm);
  flex-shrink: 0;
}

.vocab-checkbox input[type="checkbox"] {
  width: 20px;
  height: 20px;
  accent-color: var(--color-primary);
  cursor: pointer;
}

/* Selection Controls */
.selection-controls {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--space-sm) var(--space-md);
  background: var(--color-bg-tertiary);
  border-radius: var(--radius-md);
  margin-bottom: var(--space-md);
}

.selection-buttons {
  display: flex;
  gap: var(--space-xs);
}

/* Scrollbar Styling */
::-webkit-scrollbar {
  width: 6px;
  height: 6px;
}

::-webkit-scrollbar-track {
  background: transparent;
}

::-webkit-scrollbar-thumb {
  background-color: var(--color-border);
  border-radius: var(--radius-full);
}

/* Focus Visible */
:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

/* Reduced Motion */
@media (prefers-reduced-motion: reduce) {

  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }

  .btn:hover,
  .card:hover,
  .nav-item:hover,
  .flashcard:hover {
    transform: none !important;
  }
}

/* Daily Progress Bar */
.daily-progress {
  background: var(--color-bg-tertiary);
  border-radius: var(--radius-full);
  height: 12px;
  overflow: hidden;
  width: 100%;
}

.daily-progress-fill {
  background: linear-gradient(90deg, var(--color-primary), #22d3ee);
  height: 100%;
  border-radius: var(--radius-full);
  transition: width 0.3s ease;
}

.daily-progress-fill.complete {
  background: linear-gradient(90deg, #10b981, #34d399);
}

/* Streak Fire Animation */
.streak-fire {
  display: inline-block;
  animation: flicker 0.5s ease-in-out infinite alternate;
}

@keyframes flicker {
  0% {
    transform: scale(1) rotate(-2deg);
    opacity: 0.9;
  }

  100% {
    transform: scale(1.1) rotate(2deg);
    opacity: 1;
  }
}

/* Progress Label */
.progress-label {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 0.5rem;
  font-size: var(--font-size-sm);
}

.progress-count {
  font-weight: 600;
  color: var(--color-text);
}

/* Print Styles */
@media print {

  .bottom-nav,
  .app-header {
    display: none;
  }

  .app-main {
    padding-bottom: 0;
  }
}

/* Home View */
.home-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1.5rem;
}

.home-title {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--color-text);
  margin: 0;
}

.home-streak-card {
  background: linear-gradient(135deg, #f59e0b, #d97706);
  color: white;
  padding: 1rem 1.25rem;
  border-radius: var(--radius-lg);
  display: flex;
  align-items: center;
  gap: 1.25rem;
  margin-bottom: 1.5rem;
  box-shadow: 0 4px 15px rgba(217, 119, 6, 0.3);
}

.streak-icon-circle {
  width: 42px;
  height: 42px;
  background: white;
  color: #d97706;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.streak-info {
  display: flex;
  flex-direction: column;
}

.streak-count {
  font-size: 1.75rem;
  font-weight: 800;
  line-height: 1.1;
}

.streak-subtitle {
  font-size: 0.875rem;
  font-weight: 600;
  opacity: 0.95;
}

.home-progress-card {
  margin-bottom: 1.5rem;
}

.goal-complete-message {
  color: #10b981;
  font-weight: 600;
  margin-top: 0.75rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.goal-remaining {
  color: var(--color-text-secondary);
  font-size: 0.875rem;
  margin-top: 0.5rem;
}

.home-actions {
  margin-bottom: 1.5rem;
}

.btn-large {
  width: 100%;
  padding: 1rem;
  font-size: 1.125rem;
}

.mini-stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1rem;
  text-align: center;
}

.mini-stat-value {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--color-primary);
}

.mini-stat-label {
  font-size: 0.75rem;
  color: var(--color-text-secondary);
  text-transform: uppercase;
}

/* Celebration Overlay */
.celebration-overlay {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0, 0, 0, 0.7);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1000;
  animation: fadeIn 0.3s ease;
}

.celebration-content {
  text-align: center;
  color: white;
  animation: scaleIn 0.5s ease;
}

.celebration-emoji {
  font-size: 4rem;
  animation: bounce 0.6s ease infinite;
}

.celebration-title {
  font-size: 1.75rem;
  font-weight: 700;
  margin: 1rem 0 0.5rem;
}

.celebration-subtitle {
  font-size: 1rem;
  opacity: 0.9;
  margin-bottom: 1.5rem;
}

.celebration-streak {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  font-size: 1.25rem;
  margin-bottom: 1.5rem;
}

.celebration-btn {
  background: var(--color-primary);
  color: white;
  border: none;
  padding: 0.75rem 2rem;
  border-radius: 9999px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
}

.celebration-btn:hover {
  background: var(--color-primary-hover);
}

@keyframes scaleIn {
  from {
    transform: scale(0.8);
    opacity: 0;
  }

  to {
    transform: scale(1);
    opacity: 1;
  }
}

@keyframes bounce {

  0%,
  100% {
    transform: translateY(0);
  }

  50% {
    transform: translateY(-10px);
  }
}

/* Continue Last Category Section */
.home-continue {
  margin-bottom: 1rem;
}

.home-continue .card-body {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.continue-label {
  font-size: 0.75rem;
  color: var(--color-text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.continue-category {
  flex: 1;
  font-weight: 600;
  color: var(--color-text);
}

/* ============================================
   UIVERSE.IO INSPIRED EFFECTS
   Premium animations and visual effects
   ============================================ */

/* Enhanced Card with Gradient Glow Effect */
.card {
  position: relative;
  z-index: 1;
}

.card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  border-radius: inherit;
  background: linear-gradient(135deg, var(--color-primary) 0%, #8b5cf6 50%, #ec4899 100%);
  opacity: 0;
  z-index: -1;
  transition: opacity 0.3s ease;
  filter: blur(15px);
  transform: translateY(5px) scale(0.95);
}

.card:hover::before {
  opacity: 0.2;
}

[data-theme="dark"] .card:hover::before {
  opacity: 0.3;
}

/* Glow Button Effect */
.btn-primary {
  position: relative;
  overflow: hidden;
  background: linear-gradient(135deg, var(--color-primary) 0%, #0e7490 100%);
}

.btn-primary::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.3), transparent);
  transition: left 0.5s ease;
}

.btn-primary:hover::before {
  left: 100%;
}

.btn-primary::after {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: inherit;
  background: linear-gradient(135deg, var(--color-primary) 0%, #0ea5e9 100%);
  opacity: 0;
  transition: opacity 0.3s ease;
  z-index: -1;
  filter: blur(20px);
}

.btn-primary:hover::after {
  opacity: 0.5;
}

/* Neumorphic Form Inputs */
.form-input {
  background-color: var(--color-bg);
  border: none;
  box-shadow:
    inset 2px 2px 5px rgba(0, 0, 0, 0.1),
    inset -2px -2px 5px rgba(255, 255, 255, 0.5);
  transition: box-shadow 0.3s ease, transform 0.2s ease;
}

[data-theme="dark"] .form-input {
  box-shadow:
    inset 2px 2px 5px rgba(0, 0, 0, 0.3),
    inset -2px -2px 5px rgba(255, 255, 255, 0.05);
  border: 1px solid var(--color-border);
}

.form-input:focus {
  box-shadow:
    inset 2px 2px 5px rgba(0, 0, 0, 0.15),
    inset -2px -2px 5px rgba(255, 255, 255, 0.3),
    0 0 0 3px rgba(6, 182, 212, 0.2);
  transform: scale(1.01);
}

[data-theme="dark"] .form-input:focus {
  box-shadow:
    inset 2px 2px 5px rgba(0, 0, 0, 0.4),
    inset -2px -2px 5px rgba(255, 255, 255, 0.03),
    0 0 0 3px rgba(6, 182, 212, 0.3);
}

/* Vocab Item Glow Effect on Hover */
.vocab-item-glow {
  position: absolute;
  inset: 0;
  border-radius: inherit;
  background: linear-gradient(-45deg, rgba(6, 182, 212, 0.1) 0%, rgba(139, 92, 246, 0.1) 100%);
  opacity: 0;
  transition: opacity 0.3s ease;
  pointer-events: none;
  z-index: 0;
}

.vocab-item:hover .vocab-item-glow {
  opacity: 1;
}

/* Flashcard 3D Flip Enhancement */
.flashcard {
  transition: transform 0.6s cubic-bezier(0.4, 0, 0.2, 1);
}

/* Flashcard Enhanced Shadow (no pseudo-elements to avoid 3D issues) */
.flashcard-front,
.flashcard-back {
  box-shadow:
    0 4px 6px rgba(0, 0, 0, 0.1),
    0 10px 20px rgba(0, 0, 0, 0.05);
  transition: box-shadow 0.3s ease, border-color 0.3s ease;
}

.flashcard:hover .flashcard-front {
  box-shadow:
    0 8px 25px rgba(6, 182, 212, 0.25),
    0 15px 35px rgba(139, 92, 246, 0.15);
  border-color: var(--color-primary);
}

.flashcard.flipped .flashcard-back {
  box-shadow:
    0 8px 25px rgba(6, 182, 212, 0.3),
    0 15px 35px rgba(139, 92, 246, 0.2);
  border-color: var(--color-primary);
}

/* Multiple Choice Option Enhancement */
.mc-option {
  position: relative;
  overflow: hidden;
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.mc-option::before {
  content: '';
  position: absolute;
  top: 50%;
  left: 50%;
  width: 0;
  height: 0;
  background: radial-gradient(circle, var(--color-primary-light) 0%, transparent 70%);
  transform: translate(-50%, -50%);
  transition: width 0.4s ease, height 0.4s ease;
  z-index: 0;
}

.mc-option:hover::before {
  width: 300px;
  height: 300px;
}

.mc-option:hover {
  transform: translateY(-3px) scale(1.02);
  border-color: var(--color-primary);
  box-shadow: 0 8px 25px rgba(6, 182, 212, 0.2);
}

/* Filter Chip Pill Animation */
.filter-chip {
  position: relative;
  overflow: hidden;
}

.filter-chip::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(6, 182, 212, 0.2), transparent);
  transition: left 0.5s ease;
}

.filter-chip:hover::before {
  left: 100%;
}

/* Mode Card Gradient Border */
.mode-card {
  position: relative;
  background: var(--color-bg-secondary);
  overflow: hidden;
}

.mode-card::before {
  content: '';
  position: absolute;
  inset: 0;
  padding: 2px;
  background: linear-gradient(135deg, var(--color-primary), #8b5cf6, #ec4899);
  -webkit-mask: linear-gradient(#fff 0 0) content-box, linear-gradient(#fff 0 0);
  mask: linear-gradient(#fff 0 0) content-box, linear-gradient(#fff 0 0);
  -webkit-mask-composite: xor;
  mask-composite: exclude;
  opacity: 0;
  transition: opacity 0.3s ease;
  border-radius: inherit;
}

.mode-card:hover::before,
.mode-card.active::before {
  opacity: 1;
}

/* Pulse Animation for Active Elements */
@keyframes pulse-glow {

  0%,
  100% {
    box-shadow: 0 0 5px rgba(6, 182, 212, 0.3);
  }

  50% {
    box-shadow: 0 0 20px rgba(6, 182, 212, 0.5), 0 0 30px rgba(6, 182, 212, 0.3);
  }
}

.btn-primary:focus {
  animation: pulse-glow 2s infinite;
}

/* Stats Card Number Animation */
.stat-value {
  background: linear-gradient(135deg, var(--color-primary) 0%, #0ea5e9 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* Enhanced Progress Bar */
.daily-progress {
  position: relative;
  overflow: hidden;
}

.daily-progress::after {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 50%;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.3), transparent);
  animation: shimmer 2s infinite;
}

@keyframes shimmer {
  0% {
    left: -100%;
  }

  100% {
    left: 200%;
  }
}

.daily-progress-fill {
  background: linear-gradient(90deg, var(--color-primary) 0%, #0ea5e9 50%, #22d3ee 100%);
  background-size: 200% 100%;
  animation: gradient-flow 3s ease infinite;
}

@keyframes gradient-flow {
  0% {
    background-position: 0% 50%;
  }

  50% {
    background-position: 100% 50%;
  }

  100% {
    background-position: 0% 50%;
  }
}

/* Enhanced Fire Animation */
.streak-fire {
  display: inline-block;
  animation: fire-dance 0.5s ease-in-out infinite alternate;
  filter: drop-shadow(0 0 5px rgba(239, 68, 68, 0.5));
}

@keyframes fire-dance {
  0% {
    transform: scale(1) rotate(-3deg);
    filter: drop-shadow(0 0 5px rgba(239, 68, 68, 0.5));
  }

  100% {
    transform: scale(1.15) rotate(3deg);
    filter: drop-shadow(0 0 10px rgba(251, 146, 60, 0.7));
  }
}

/* Celebration Enhancement */
.celebration-overlay {
  backdrop-filter: blur(5px);
}

.celebration-content {
  position: relative;
}

.celebration-content::before {
  content: '';
  position: absolute;
  inset: -50px;
  background: radial-gradient(circle, rgba(6, 182, 212, 0.2) 0%, transparent 70%);
  animation: celebration-pulse 2s ease-in-out infinite;
}

@keyframes celebration-pulse {

  0%,
  100% {
    transform: scale(1);
    opacity: 0.5;
  }

  50% {
    transform: scale(1.2);
    opacity: 1;
  }
}

.celebration-emoji {
  text-shadow: 0 0 30px rgba(251, 191, 36, 0.5);
}

/* Nav Item Hover Effects */
.nav-item {
  position: relative;
}

.nav-item::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 50%;
  width: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--color-primary), #22d3ee);
  transition: width 0.3s ease, left 0.3s ease;
}

.nav-item:hover::after,
.nav-item.active::after {
  width: 60%;
  left: 20%;
}

/* Floating Label Effect for Search */
.search-wrapper .form-input:focus+svg,
.search-wrapper .form-input:not(:placeholder-shown)+svg {
  color: var(--color-primary);
  transform: translateY(-50%) scale(0.9);
}

/* Badge Glow */
.badge {
  position: relative;
}

.badge-success::after {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: inherit;
  background: inherit;
  filter: blur(8px);
  opacity: 0.4;
  z-index: -1;
}

/* Ripple Effect on Click */
.btn,
.mc-option,
.mode-card,
.session-mode-btn {
  position: relative;
  overflow: hidden;
}

/* Toast Slide Animation Enhancement */
.toast {
  animation: toast-slide 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

@keyframes toast-slide {
  from {
    transform: translateX(100%) scale(0.8);
    opacity: 0;
  }

  to {
    transform: translateX(0) scale(1);
    opacity: 1;
  }
}

/* Home Card Hover Shine */
.home-progress-card,
.home-stats,
.home-continue {
  position: relative;
  overflow: hidden;
}

.home-progress-card::after,
.home-stats::after,
.home-continue::after {
  content: '';
  position: absolute;
  top: -50%;
  left: -50%;
  width: 200%;
  height: 200%;
  background: linear-gradient(45deg,
      transparent 40%,
      rgba(255, 255, 255, 0.03) 50%,
      transparent 60%);
  transform: rotate(45deg);
  transition: transform 0.6s ease;
}

.home-progress-card:hover::after,
.home-stats:hover::after,
.home-continue:hover::after {
  transform: rotate(45deg) translate(50%, 50%);
}

/* Checkbox Custom Styling */
.vocab-checkbox input[type="checkbox"] {
  appearance: none;
  width: 22px;
  height: 22px;
  border: 2px solid var(--color-border);
  border-radius: 6px;
  cursor: pointer;
  position: relative;
  transition: all 0.2s ease;
  background: var(--color-bg);
}

.vocab-checkbox input[type="checkbox"]:checked {
  background: linear-gradient(135deg, var(--color-primary), #0ea5e9);
  border-color: var(--color-primary);
}

.vocab-checkbox input[type="checkbox"]:checked::after {
  content: '✓';
  position: absolute;
  color: white;
  font-size: 14px;
  font-weight: bold;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
}

.vocab-checkbox input[type="checkbox"]:hover {
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(6, 182, 212, 0.15);
}

/* Selected vocab item highlight */
.vocab-item--selected::before {
  opacity: 1 !important;
  transform: none;
}

.vocab-item--selected::after {
  background: var(--color-bg) !important;
}

.vocab-item--selected {
  box-shadow: 0 0 12px rgba(6, 182, 212, 0.2);
}

/* Sticky selection bar fixed to viewport bottom in words view */
.selection-sticky-bar {
  position: fixed;
  left: 50%;
  transform: translateX(-50%);
  bottom: calc(var(--nav-height) + var(--space-sm) + var(--safe-area-bottom));
  width: min(600px, calc(100vw - (2 * var(--space-md))));
  z-index: 120;
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-sm) var(--space-md);
  background: linear-gradient(135deg, rgba(6, 182, 212, 0.15), rgba(139, 92, 246, 0.1));
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid rgba(6, 182, 212, 0.3);
  border-radius: var(--radius-lg);
  box-shadow: 0 -4px 20px rgba(0, 0, 0, 0.15);
}

/* Keep list content visible above fixed selection bar */
#view-words {
  padding-bottom: calc(120px + var(--nav-height) + var(--safe-area-bottom));
}

.selection-sticky-info {
  display: flex;
  align-items: baseline;
  gap: 4px;
  flex-shrink: 0;
}

.selection-sticky-count {
  font-weight: 800;
  font-size: 1.1rem;
  color: var(--color-primary);
}

.selection-sticky-label {
  font-size: 0.75rem;
  color: var(--color-text-muted);
}

.selection-sticky-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 4px;
  flex: 1;
  min-width: 0;
  overflow: hidden;
}

.selection-sticky-chip {
  display: inline-flex;
  align-items: center;
  gap: 3px;
  background: var(--color-bg-secondary);
  color: var(--color-text-muted);
  padding: 2px 8px;
  border-radius: var(--radius-full);
  font-size: 0.65rem;
  border: 1px solid var(--color-border);
  white-space: nowrap;
}

.selection-sticky-chip-more {
  background: rgba(6, 182, 212, 0.18);
  color: var(--color-primary);
  border-color: rgba(6, 182, 212, 0.35);
  font-weight: 600;
}

.selection-sticky-chip strong {
  color: var(--color-primary);
}

.selection-sticky-clear {
  flex-shrink: 0;
}

/* AGB content */
.agb-content h3 {
  margin-bottom: var(--space-md);
  color: var(--color-primary);
}

.agb-content h4 {
  margin-top: var(--space-md);
  margin-bottom: var(--space-xs);
  font-size: var(--font-size-sm);
  color: var(--color-text);
}

.agb-content p {
  font-size: var(--font-size-sm);
  line-height: 1.6;
  color: var(--color-text-muted);
  margin-bottom: var(--space-xs);
}

/* Filter chip with selection count */
.filter-chip.has-selection {
  border-color: var(--color-primary);
}

.chip-count {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background: var(--color-primary);
  color: white;
  font-size: 0.65rem;
  font-weight: 700;
  min-width: 18px;
  height: 18px;
  border-radius: 9px;
  padding: 0 4px;
  margin-left: 4px;
}

/* Smooth Page Transitions */
.view {
  animation: page-enter 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

@keyframes page-enter {
  from {
    opacity: 0;
    transform: translateY(20px);
  }

  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* Loading Skeleton Shimmer */
@keyframes skeleton-loading {
  0% {
    background-position: -200% 0;
  }

  100% {
    background-position: 200% 0;
  }
}

.skeleton {
  background: linear-gradient(90deg,
      var(--color-bg-tertiary) 25%,
      var(--color-bg-secondary) 50%,
      var(--color-bg-tertiary) 75%);
  background-size: 200% 100%;
  animation: skeleton-loading 1.5s infinite;
  border-radius: var(--radius-md);
}

/* ============================================
   DASHBOARD / HOME VIEW ENHANCEMENTS
   ============================================ */

.dashboard {
  padding: var(--space-md) 0;
  display: flex;
  flex-direction: column;
  gap: var(--space-lg);
}

.dashboard-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  margin-bottom: var(--space-sm);
}

.greeting-title {
  font-size: var(--font-size-3xl);
  font-weight: 800;
  letter-spacing: -0.025em;
  color: var(--color-text);
}

.greeting-subtitle {
  color: var(--color-text-secondary);
  font-size: var(--font-size-base);
}

.streak-badge {
  background: var(--color-bg-secondary);
  padding: var(--space-sm) var(--space-md);
  border-radius: var(--radius-full);
  display: flex;
  align-items: center;
  gap: var(--space-xs);
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--color-border);
  opacity: 0.5;
  transition: all 0.3s ease;
}

.streak-badge.active {
  opacity: 1;
  border-color: var(--color-warning);
  background: var(--color-warning-light);
}

[data-theme="dark"] .streak-badge.active {
  background: rgba(120, 53, 15, 0.3);
}

.dashboard-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-md);
}

@media (max-width: 480px) {
  .dashboard-grid {
    grid-template-columns: 1fr;
  }
}

.db-card {
  background: var(--color-bg-secondary);
  border-radius: var(--radius-xl);
  padding: var(--space-lg);
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
  box-shadow: var(--shadow-md);
  border: 1px solid var(--color-border);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.db-card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

.db-card-header {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.db-card-header h3 {
  font-size: var(--font-size-sm);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-text-secondary);
  margin: 0;
}

.db-card-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 1.5rem;
  height: 1.5rem;
  color: var(--color-primary);
  background: var(--color-primary-light);
  border-radius: var(--radius-md);
}

.goal-progress-container {
  position: relative;
  display: flex;
  justify-content: center;
  align-items: center;
}

.goal-ring {
  width: 100px;
  height: 100px;
  transform: rotate(-90deg);
}

.ring-bg {
  fill: none;
  stroke: var(--color-bg-tertiary);
  stroke-width: 8;
}

.ring-fill {
  fill: none;
  stroke: var(--color-primary);
  stroke-width: 8;
  stroke-linecap: round;
  transition: stroke-dasharray 1s ease;
}

.goal-card.reached .ring-fill {
  stroke: var(--color-success);
}

.goal-text {
  position: absolute;
  display: flex;
  flex-direction: column;
  align-items: center;
}

.goal-current {
  font-size: var(--font-size-2xl);
  font-weight: 800;
  color: var(--color-text);
  line-height: 1;
}

.goal-total {
  font-size: var(--font-size-xs);
  color: var(--color-text-secondary);
}

.db-card-footer {
  font-size: var(--font-size-sm);
  font-weight: 600;
  text-align: center;
  margin: 0;
  color: var(--color-text-secondary);
}

.stats-mini-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.35rem var(--space-sm);
}

.mini-stat-item {
  display: flex;
  flex-direction: column;
}

.mini-stat-item .val {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--color-text);
}

.mini-stat-item .lbl {
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
}

.mastery-bar-container {
  margin-top: var(--space-xs);
}

.mastery-label {
  font-size: var(--font-size-xs);
  font-weight: 600;
  margin-bottom: 4px;
  color: var(--color-text-secondary);
}

.mastery-bar-bg {
  height: 6px;
  background: var(--color-bg-tertiary);
  border-radius: var(--radius-full);
  overflow: hidden;
}

.mastery-bar-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--color-primary), #10b981);
  border-radius: var(--radius-full);
  transition: width 1s ease;
}

/* Continue Action */
.continue-action {
  background: linear-gradient(135deg, var(--color-primary-hover), var(--color-primary));
  color: white;
  display: flex;
  align-items: center;
  padding: var(--space-md) var(--space-lg);
  border-radius: var(--radius-xl);
  gap: var(--space-md);
  cursor: pointer;
  border: none;
  transition: transform 0.2s ease;
}

.continue-action:hover {
  transform: scale(1.02);
}

.continue-icon {
  font-size: 24px;
  background: rgba(255, 255, 255, 0.2);
  width: 48px;
  height: 48px;
  display: flex;
  justify-content: center;
  align-items: center;
  border-radius: var(--radius-lg);
}

.continue-info {
  flex: 1;
  display: flex;
  flex-direction: column;
}

.continue-info .label {
  font-size: var(--font-size-xs);
  text-transform: uppercase;
  font-weight: 700;
  opacity: 0.8;
}

.continue-info .category-name {
  font-size: var(--font-size-lg);
  font-weight: 700;
}

/* Main Actions */
.main-actions {
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
}

.action-button {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  padding: var(--space-lg);
  border-radius: var(--radius-xl);
  border: 1px solid var(--color-border);
  cursor: pointer;
  text-align: left;
  background: var(--color-bg-secondary);
  transition: all 0.2s ease;
  box-shadow: var(--shadow-sm);
}

.action-button:hover {
  border-color: var(--color-primary);
  background: var(--color-bg-tertiary);
  transform: translateX(4px);
}

.action-button.primary {
  border-color: var(--color-primary);
  background: var(--color-primary-light);
}

[data-theme="dark"] .action-button.primary {
  background: rgba(6, 182, 212, 0.1);
}

.action-button .icon {
  font-size: 28px;
  width: 56px;
  height: 56px;
  background: var(--color-bg-tertiary);
  display: flex;
  justify-content: center;
  align-items: center;
  border-radius: var(--radius-lg);
  flex-shrink: 0;
}

.action-button.primary .icon {
  background: var(--color-primary);
  color: white;
}

.action-button .text {
  display: flex;
  flex-direction: column;
}

.action-button .title {
  font-size: var(--font-size-lg);
  font-weight: 700;
  color: var(--color-text);
}

.action-button .desc {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
}

/* Recent Stats */
.recent-stats {
  padding: var(--space-lg);
}

.card-header-simple {
  font-size: var(--font-size-base);
  font-weight: 700;
  margin-bottom: var(--space-md);
  color: var(--color-text);
}

.quick-stats {
  display: flex;
  justify-content: space-between;
  text-align: center;
}

.qs-item {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.qs-val {
  font-size: var(--font-size-lg);
  font-weight: 800;
  color: var(--color-primary);
}

.qs-lbl {
  font-size: 10px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-text-muted);
}

/* ============================================
   PREMIUM UIVERSE BUTTONS
   ============================================ */

.btn-uiverse {
  --round: 0.75rem;
  --primary-color: #212121;
  --secondary-color: rgba(255, 255, 255, 0.3);
  cursor: pointer;
  position: relative;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  transition: all 0.25s ease;
  background: radial-gradient(65.28% 65.28% at 50% 100%,
      var(--secondary-color) 0%,
      rgba(255, 255, 255, 0) 100%),
    linear-gradient(0deg, var(--primary-color), var(--primary-color));
  border-radius: var(--round);
  border: none;
  outline: none;
  padding: 10px 16px;
  min-height: 44px;
  text-decoration: none;
}

.btn-uiverse-error {
  --primary-color: #ef4444;
  --secondary-color: rgba(239, 68, 68, 0.8);
}

.btn-uiverse-success {
  --primary-color: #10b981;
  --secondary-color: rgba(16, 185, 129, 0.8);
}

.btn-uiverse::before,
.btn-uiverse::after {
  content: "";
  position: absolute;
  inset: var(--space);
  transition: all 0.5s ease-in-out;
  border-radius: calc(var(--round) - var(--space));
  z-index: 0;
}

.btn-uiverse::before {
  --space: 1px;
  background: linear-gradient(177.95deg,
      rgba(255, 255, 255, 0.19) 0%,
      rgba(255, 255, 255, 0) 100%);
}

.btn-uiverse::after {
  --space: 2px;
  background: radial-gradient(65.28% 65.28% at 50% 100%,
      var(--secondary-color) 0%,
      rgba(255, 255, 255, 0) 100%),
    linear-gradient(0deg, var(--primary-color), var(--primary-color));
}

.btn-uiverse:active {
  transform: scale(0.95);
}

.btn-uiverse .fold {
  z-index: 1;
  position: absolute;
  top: 0;
  right: 0;
  height: 0.75rem;
  width: 0.75rem;
  display: inline-block;
  transition: all 0.5s ease-in-out;
  background: radial-gradient(100% 75% at 55%,
      var(--secondary-color) 0%,
      rgba(255, 255, 255, 0) 100%);
  box-shadow: 0 0 3px rgba(0, 0, 0, 0.3);
  border-bottom-left-radius: 0.4rem;
  border-top-right-radius: var(--round);
}

.btn-uiverse .fold::after {
  content: "";
  position: absolute;
  top: 0;
  right: 0;
  width: 150%;
  height: 150%;
  transform: rotate(45deg) translateX(0%) translateY(-12px);
  background-color: #e8e8e8;
  pointer-events: none;
}

.btn-uiverse:hover .fold {
  margin-top: -1rem;
  margin-right: -1rem;
}

.btn-uiverse .points_wrapper {
  overflow: hidden;
  width: 100%;
  height: 100%;
  pointer-events: none;
  position: absolute;
  z-index: 1;
  top: 0;
  left: 0;
}

.btn-uiverse .point {
  bottom: -10px;
  position: absolute;
  animation: floating-points infinite ease-in-out;
  pointer-events: none;
  width: 2px;
  height: 2px;
  background-color: #fff;
  border-radius: 9999px;
  display: block;
}

@keyframes floating-points {
  0% {
    transform: translateY(0);
  }

  85% {
    opacity: 0;
  }

  100% {
    transform: translateY(-55px);
    opacity: 0;
  }
}

.btn-uiverse .point:nth-child(1) {
  left: 10%;
  animation-duration: 2.3s;
  animation-delay: 0.2s;
}

.btn-uiverse .point:nth-child(2) {
  left: 30%;
  animation-duration: 2.5s;
  animation-delay: 0.5s;
}

.btn-uiverse .point:nth-child(3) {
  left: 25%;
  animation-duration: 2.2s;
  animation-delay: 0.1s;
}

.btn-uiverse .point:nth-child(4) {
  left: 44%;
  animation-duration: 2.0s;
}

.btn-uiverse .point:nth-child(5) {
  left: 50%;
  animation-duration: 1.9s;
}

.btn-uiverse .point:nth-child(6) {
  left: 75%;
  animation-duration: 1.5s;
  animation-delay: 0.8s;
}

.btn-uiverse .point:nth-child(7) {
  left: 88%;
  animation-duration: 2.1s;
  animation-delay: 0.2s;
}

.btn-uiverse .point:nth-child(8) {
  left: 58%;
  animation-duration: 2.3s;
  animation-delay: 0.1s;
}

.btn-uiverse .point:nth-child(9) {
  left: 95%;
  animation-duration: 2.6s;
  animation-delay: 0.3s;
}

.btn-uiverse .point:nth-child(10) {
  left: 65%;
  animation-duration: 2.4s;
  animation-delay: 0.2s;
}

.btn-uiverse .inner {
  z-index: 2;
  gap: 8px;
  position: relative;
  width: 100%;
  color: white;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 14px;
  font-weight: 600;
  transition: color 0.2s ease-in-out;
}

.btn-uiverse .inner svg {
  width: 18px;
  height: 18px;
  transition: fill 0.1s linear;
  stroke: white;
}

.btn-uiverse:hover .inner svg {
  fill: transparent;
  animation: dasharray 1s linear forwards, filled 0.1s linear forwards 0.95s;
}

@keyframes dasharray {
  from {
    stroke-dasharray: 0 0 0 0;
  }

  to {
    stroke-dasharray: 68 68 0 0;
  }
}

@keyframes filled {
  to {
    fill: white;
  }
}