/* CSS Custom Properties */
:root {
  --color-text: #5a5a5a;
  --color-text-light: #888;
  --color-bg: #ffffff;
  --color-bg-alt: #f5f5f5;
  --color-answer-box: #e8e8e8;
  --color-answer-border: #ccc;
  --color-primary: #4a7c59;
  --color-primary-hover: #3d6649;
  --color-danger: #c44;
  --color-danger-hover: #a33;
  --color-success: #4a7c59;
  --color-error: #c44;
  --color-star: #f5a623;
  --color-star-empty: #ccc;
  --font-main: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.1);
  --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1);
  --radius-sm: 4px;
  --radius-md: 8px;
  --transition-fast: 150ms ease;
  --transition-normal: 250ms ease;
}

/* Reset & Base */
*, *::before, *::after {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: var(--font-main);
  background: var(--color-bg);
  color: var(--color-text);
  line-height: 1.5;
  min-height: 100vh;
}

button {
  font-family: inherit;
  font-size: inherit;
  cursor: pointer;
}

input, select {
  font-family: inherit;
  font-size: inherit;
}

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

/* App Header */
.app-header {
  background: var(--color-bg);
  padding: 1rem 1rem 0;
  position: sticky;
  top: 0;
  z-index: 100;
}

.app-header h1 {
  margin: 0 0 0.75rem 0;
  font-size: 1.5rem;
  font-weight: 600;
  text-align: center;
  color: var(--color-text);
}

/* Tab Navigation - Underline Style */
.tab-nav {
  display: flex;
  justify-content: center;
  align-items: stretch;
  border-bottom: 1px solid var(--color-answer-border);
  position: relative;
}

.tab-nav [role="tab"] {
  background: transparent;
  border: none;
  border-bottom: 2px solid transparent;
  padding: 0.75rem 1.5rem;
  margin-bottom: -1px;
  color: var(--color-text-light);
  font-weight: 500;
  font-size: 1rem;
  transition: color var(--transition-fast), border-color var(--transition-fast);
}

.tab-nav [role="tab"]:hover {
  color: var(--color-text);
}

.tab-nav [role="tab"][aria-selected="true"] {
  color: var(--color-primary);
  border-bottom-color: var(--color-primary);
}

/* Settings Toggle - Improved */
.settings-toggle {
  display: flex;
  align-items: center;
  gap: 0.375rem;
  background: transparent;
  border: none;
  border-radius: var(--radius-sm);
  padding: 0.5rem 0.75rem;
  color: var(--color-text-light);
  font-size: 0.875rem;
  position: absolute;
  right: 0;
  top: 50%;
  transform: translateY(-50%);
  transition: background var(--transition-fast), color var(--transition-fast);
}

.settings-toggle:hover {
  background: var(--color-bg-alt);
  color: var(--color-text);
}

.settings-toggle .settings-icon {
  font-size: 1.125rem;
  line-height: 1;
}

.settings-toggle .settings-label {
  font-weight: 500;
}

/* Tab Panels */
.tab-panel {
  padding: 1rem;
  max-width: 800px;
  margin: 0 auto;
}

.tab-panel[hidden] {
  display: none;
}

/* Study Controls */
.study-controls {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  align-items: center;
  justify-content: center;
  margin-bottom: 1.5rem;
  padding: 0.75rem;
  background: var(--color-bg-alt);
  border-radius: var(--radius-md);
}

.mode-toggle {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  cursor: pointer;
}

.mode-toggle input {
  width: 1.25rem;
  height: 1.25rem;
  accent-color: var(--color-primary);
}

.filter-controls {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.filter-controls select {
  padding: 0.375rem 0.75rem;
  border: 1px solid var(--color-answer-border);
  border-radius: var(--radius-sm);
  background: var(--color-bg);
}

#shuffle-btn {
  background: var(--color-bg);
  border: 1px solid var(--color-answer-border);
  padding: 0.375rem 0.75rem;
  border-radius: var(--radius-sm);
  transition: background var(--transition-fast), border-color var(--transition-fast);
}

#shuffle-btn:hover {
  background: var(--color-answer-box);
}

#shuffle-btn[aria-pressed="true"] {
  background: var(--color-primary);
  border-color: var(--color-primary);
  color: white;
}

#fullscreen-btn {
  background: var(--color-bg);
  border: 1px solid var(--color-answer-border);
  padding: 0.375rem 0.75rem;
  border-radius: var(--radius-sm);
  transition: background var(--transition-fast), border-color var(--transition-fast);
}

#fullscreen-btn:hover {
  background: var(--color-answer-box);
}

/* Fullscreen Mode */
.fullscreen-mode {
  position: fixed;
  inset: 0;
  z-index: 1000;
  background: var(--color-bg);
  display: flex;
  flex-direction: column;
}

.fullscreen-mode .study-header {
  position: fixed;
  top: 1rem;
  left: 1rem;
  right: 1rem;
  display: flex;
  justify-content: space-between;
  z-index: 1010;
}

.fullscreen-mode .flashcard {
  flex: 1;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  max-width: 90vw;
  width: 100%;
  margin: 0 auto;
  box-shadow: none;
  border-radius: 0;
  background: transparent;
  padding: 4rem 2rem 8rem;
}

.fullscreen-mode .front-text {
  font-size: clamp(3rem, 10vw, 7rem);
  text-align: center;
  margin-bottom: 2rem;
}

.fullscreen-mode .back-text {
  font-size: clamp(2rem, 6vw, 4rem);
  text-align: center;
}

.fullscreen-mode .answer-area {
  width: 100%;
  max-width: 800px;
  min-width: 300px;
}

.fullscreen-mode .card-navigation {
  position: fixed;
  bottom: 2rem;
  left: 50%;
  transform: translateX(-50%);
  background: rgba(255, 255, 255, 0.95);
  padding: 0.75rem 1.5rem;
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-md);
  z-index: 1010;
}

.fullscreen-mode .card-meta {
  text-align: center;
}

.fullscreen-mode .empty-state {
  display: none;
}

/* Exit fullscreen button */
.exit-fullscreen-btn {
  position: absolute;
  top: 1rem;
  right: 1rem;
  background: var(--color-bg);
  border: 1px solid var(--color-answer-border);
  padding: 0.5rem 1rem;
  border-radius: var(--radius-sm);
  font-size: 0.875rem;
  z-index: 20;
  cursor: pointer;
}

.exit-fullscreen-btn:hover {
  background: var(--color-answer-box);
}

/* Flashcard */
.flashcard {
  background: var(--color-bg);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-md);
  padding: 2rem 1.5rem;
  text-align: center;
  position: relative;
  min-height: 300px;
  display: flex;
  flex-direction: column;
  justify-content: center;
}

.star-toggle {
  position: absolute;
  top: 1rem;
  right: 1rem;
  background: transparent;
  border: none;
  font-size: 1.75rem;
  color: var(--color-star-empty);
  transition: color var(--transition-fast), transform var(--transition-fast);
  padding: 0.25rem;
}

.star-toggle:hover {
  transform: scale(1.1);
}

.star-toggle[aria-pressed="true"] {
  color: var(--color-star);
}

.front-text {
  font-size: clamp(2rem, 8vw, 4rem);
  font-weight: 400;
  color: var(--color-text);
  margin: 0 0 1.5rem 0;
  line-height: 1.2;
}

/* Answer Area */
.answer-area {
  background: var(--color-answer-box);
  border: 1px solid var(--color-answer-border);
  border-radius: var(--radius-md);
  padding: 1.5rem;
  min-height: 100px;
  width: 100%;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  transition: background var(--transition-normal), border-color var(--transition-normal);
  cursor: pointer;
}

.answer-area.revealed {
  background: transparent;
  border-color: transparent;
  cursor: default;
}

.reveal-content {
  width: 100%;
  text-align: center;
}

.hint-text {
  color: var(--color-text-light);
  font-size: 1rem;
  margin: 0;
}

.back-text {
  font-size: clamp(1.5rem, 6vw, 2.5rem);
  color: var(--color-text);
  margin: 0;
  animation: fadeIn var(--transition-normal);
}

.back-text[hidden] {
  display: none;
}

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

/* Quiz Form */
.quiz-form {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  justify-content: center;
  width: 100%;
}

.quiz-form[hidden] {
  display: none;
}

.quiz-form input[type="text"] {
  flex: 1;
  min-width: 150px;
  max-width: 300px;
  padding: 0.75rem 1rem;
  border: 2px solid var(--color-answer-border);
  border-radius: var(--radius-sm);
  font-size: 1.25rem;
  text-align: center;
}

.quiz-form input[type="text"]:focus {
  outline: none;
  border-color: var(--color-primary);
}

.quiz-form button {
  background: var(--color-primary);
  color: white;
  border: none;
  padding: 0.75rem 1.5rem;
  border-radius: var(--radius-sm);
  transition: background var(--transition-fast);
}

.quiz-form button:hover {
  background: var(--color-primary-hover);
}

/* Quiz Feedback */
.quiz-feedback {
  margin: 0.75rem 0 0 0;
  font-size: 1.25rem;
  font-weight: 500;
}

.quiz-feedback[hidden] {
  display: none;
}

.quiz-feedback.correct {
  color: var(--color-success);
}

.quiz-feedback.incorrect {
  color: var(--color-error);
}

/* Card Meta */
.card-meta {
  margin-top: 1rem;
  padding-top: 1rem;
  border-top: 1px solid var(--color-answer-border);
}

.card-meta[hidden] {
  display: none;
}

.comment {
  color: var(--color-text-light);
  font-style: italic;
  margin: 0;
}

/* Card Navigation */
.card-navigation {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 1rem;
  margin-top: 1.5rem;
}

.card-navigation button {
  background: var(--color-bg);
  border: 1px solid var(--color-answer-border);
  padding: 0.75rem 1.25rem;
  border-radius: var(--radius-sm);
  transition: background var(--transition-fast), border-color var(--transition-fast);
}

.card-navigation button:hover:not(:disabled) {
  background: var(--color-answer-box);
  border-color: var(--color-text-light);
}

.card-navigation button:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.progress {
  font-size: 1rem;
  color: var(--color-text-light);
  min-width: 80px;
  text-align: center;
}

/* Empty State */
.empty-state {
  text-align: center;
  color: var(--color-text-light);
  padding: 2rem;
}

.empty-state[hidden] {
  display: none;
}

.link-btn {
  background: none;
  border: none;
  color: var(--color-primary);
  text-decoration: underline;
  cursor: pointer;
  padding: 0;
  font-size: inherit;
}

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

/* Card Form */
.card-form {
  margin-bottom: 2rem;
}

.card-form fieldset {
  border: 1px solid var(--color-answer-border);
  border-radius: var(--radius-md);
  padding: 1.5rem;
  background: var(--color-bg-alt);
}

.card-form legend {
  font-weight: 600;
  padding: 0 0.5rem;
}

.form-row {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  margin-bottom: 1rem;
}

.form-row:last-child {
  margin-bottom: 0;
}

.form-row label {
  flex: 1;
  min-width: 200px;
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}

.form-row label.full-width {
  flex-basis: 100%;
}

.form-row label span {
  font-weight: 500;
  font-size: 0.875rem;
}

.form-row input[type="text"] {
  padding: 0.5rem 0.75rem;
  border: 1px solid var(--color-answer-border);
  border-radius: var(--radius-sm);
}

.form-row input[type="text"]:focus {
  outline: none;
  border-color: var(--color-primary);
}

.form-actions {
  align-items: center;
  justify-content: space-between;
}

.checkbox-label {
  flex-direction: row !important;
  align-items: center;
  min-width: auto;
}

.checkbox-label input {
  width: 1.25rem;
  height: 1.25rem;
  accent-color: var(--color-primary);
}

.card-form button[type="submit"] {
  background: var(--color-primary);
  color: white;
  border: none;
  padding: 0.625rem 1.5rem;
  border-radius: var(--radius-sm);
  transition: background var(--transition-fast);
}

.card-form button[type="submit"]:hover {
  background: var(--color-primary-hover);
}

/* Card List Grid */
.card-list {
  margin-bottom: 1.5rem;
}

.cards-grid {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1rem;
}

.card-item {
  background: var(--color-bg);
  border: 1px solid var(--color-answer-border);
  border-radius: var(--radius-md);
  padding: 1rem;
  display: grid;
  grid-template-areas:
    "front star"
    "back back"
    "note note"
    "actions actions";
  grid-template-columns: 1fr auto;
  gap: 0.5rem;
  transition: box-shadow var(--transition-fast);
}

.card-item:hover {
  box-shadow: var(--shadow-md);
}

.card-item .card-front {
  grid-area: front;
  font-weight: 600;
  font-size: 1.1rem;
  color: var(--color-text);
}

.card-item .card-back {
  grid-area: back;
  color: var(--color-text-light);
}

.card-item .card-note {
  grid-area: note;
  font-size: 0.875rem;
  font-style: italic;
  color: var(--color-text-light);
  opacity: 0.8;
}

.card-item .card-note:empty {
  display: none;
}

.card-item .card-star {
  grid-area: star;
  font-size: 1.25rem;
  color: var(--color-star-empty);
  justify-self: end;
}

.card-item .card-star.starred {
  color: var(--color-star);
}

.card-item .card-actions {
  grid-area: actions;
  display: flex;
  gap: 0.5rem;
  padding-top: 0.5rem;
  border-top: 1px solid var(--color-answer-border);
  margin-top: 0.25rem;
}

.card-item .card-actions button {
  flex: 1;
  background: transparent;
  border: 1px solid var(--color-answer-border);
  padding: 0.375rem 0.75rem;
  border-radius: var(--radius-sm);
  font-size: 0.875rem;
  transition: background var(--transition-fast), border-color var(--transition-fast);
  cursor: pointer;
}

.card-item .card-actions button:hover {
  background: var(--color-answer-box);
}

.card-item .card-actions .delete-btn:hover {
  background: var(--color-danger);
  border-color: var(--color-danger);
  color: white;
}

/* Accessible labels */
.card-item .label {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-text-light);
  display: block;
  margin-bottom: 0.125rem;
}

/* List Actions */
.list-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-bottom: 1.5rem;
}

.list-actions button {
  background: var(--color-bg);
  border: 1px solid var(--color-answer-border);
  padding: 0.625rem 1rem;
  border-radius: var(--radius-sm);
  transition: background var(--transition-fast), border-color var(--transition-fast);
}

.list-actions button:hover {
  background: var(--color-answer-box);
}

.list-actions button.danger {
  color: var(--color-danger);
  border-color: var(--color-danger);
}

.list-actions button.danger:hover {
  background: var(--color-danger);
  color: white;
}

/* Settings Panel */
.settings-panel {
  position: fixed;
  top: 0;
  right: 0;
  width: 100%;
  max-width: 350px;
  height: 100vh;
  background: var(--color-bg);
  box-shadow: -4px 0 20px rgba(0, 0, 0, 0.15);
  z-index: 200;
  transform: translateX(100%);
  transition: transform var(--transition-normal);
  overflow-y: auto;
}

.settings-panel[hidden] {
  display: block;
}

.settings-panel.open {
  transform: translateX(0);
}

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

.settings-header h2 {
  margin: 0;
  font-size: 1.25rem;
}

.close-settings {
  background: transparent;
  border: none;
  font-size: 1.5rem;
  color: var(--color-text-light);
  padding: 0.25rem;
  line-height: 1;
}

.close-settings:hover {
  color: var(--color-text);
}

.settings-form {
  padding: 1rem 1.5rem;
}

.settings-form fieldset {
  border: none;
  padding: 0;
  margin-bottom: 1.5rem;
}

.settings-form legend {
  font-weight: 600;
  margin-bottom: 0.75rem;
  font-size: 0.875rem;
  text-transform: uppercase;
  letter-spacing: 0.025em;
  color: var(--color-text-light);
}

.settings-form label {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
  margin-bottom: 0.75rem;
}

.settings-form label span {
  font-size: 0.875rem;
}

.settings-form select {
  padding: 0.5rem;
  border: 1px solid var(--color-answer-border);
  border-radius: var(--radius-sm);
}

/* Overlay for settings */
.settings-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.3);
  z-index: 150;
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--transition-normal), visibility var(--transition-normal);
}

.settings-overlay.visible {
  opacity: 1;
  visibility: visible;
}

/* Responsive */
@media (max-width: 600px) {
  .app-header {
    padding: 0.75rem 0.75rem 0;
  }

  .app-header h1 {
    font-size: 1.25rem;
    margin-bottom: 0.5rem;
  }

  /* Tabs - ensure 44px touch targets */
  .tab-nav [role="tab"] {
    padding: 0.875rem 1rem;
    font-size: 0.9375rem;
    min-height: 44px;
  }

  /* Settings - icon only on mobile with 44px touch target */
  .settings-toggle {
    padding: 0.625rem;
    min-width: 44px;
    min-height: 44px;
    justify-content: center;
    right: 0.25rem;
  }

  .settings-toggle .settings-label {
    /* Visually hidden but accessible */
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
  }

  .settings-toggle .settings-icon {
    font-size: 1.375rem;
  }

  .tab-panel {
    padding: 0.75rem;
  }

  .flashcard {
    padding: 1.5rem 1rem;
    min-height: 250px;
  }

  .form-row label {
    min-width: 100%;
  }

  .form-actions {
    flex-direction: column;
    align-items: stretch;
    gap: 0.75rem;
  }

  .form-actions .checkbox-label {
    justify-content: flex-start;
  }

  .card-form button[type="submit"] {
    width: 100%;
  }

  .list-actions {
    flex-direction: column;
  }

  .list-actions button {
    width: 100%;
  }
}

/* Deck Management */
.deck-management {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 1.5rem;
  padding: 0.75rem 1rem;
  background: var(--color-bg-alt);
  border-radius: var(--radius-md);
}

.deck-selector {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.deck-selector label {
  font-weight: 500;
}

.deck-selector select {
  padding: 0.5rem 0.75rem;
  border: 1px solid var(--color-answer-border);
  border-radius: var(--radius-sm);
  background: var(--color-bg);
  min-width: 150px;
}

.deck-actions {
  display: flex;
  gap: 0.5rem;
}

.icon-btn {
  background: var(--color-bg);
  border: 1px solid var(--color-answer-border);
  padding: 0.375rem 0.75rem;
  border-radius: var(--radius-sm);
  font-size: 0.875rem;
  transition: background var(--transition-fast);
}

.icon-btn:hover {
  background: var(--color-answer-box);
}

.icon-btn.danger {
  color: var(--color-danger);
  border-color: var(--color-danger);
}

.icon-btn.danger:hover {
  background: var(--color-danger);
  color: white;
}

/* Card List Header */
.card-list-header {
  margin-bottom: 1rem;
}

.card-list-header h3 {
  margin: 0;
  font-size: 1rem;
  font-weight: 500;
  color: var(--color-text-light);
}

/* Session Setup */
.session-setup {
  max-width: 500px;
  margin: 0 auto;
  padding: 1.5rem;
}

.session-setup h2 {
  text-align: center;
  margin: 0 0 1.5rem 0;
  font-size: 1.5rem;
  font-weight: 500;
}

.deck-selection {
  border: 1px solid var(--color-answer-border);
  border-radius: var(--radius-md);
  padding: 1rem;
  margin-bottom: 1.5rem;
  background: var(--color-bg-alt);
}

.deck-selection legend {
  font-weight: 600;
  padding: 0 0.5rem;
}

.deck-checkboxes {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.deck-checkbox {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.5rem;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: background var(--transition-fast);
}

.deck-checkbox:hover {
  background: var(--color-answer-box);
}

.deck-checkbox input[type="checkbox"] {
  width: 1.25rem;
  height: 1.25rem;
  accent-color: var(--color-primary);
}

.deck-checkbox .deck-name {
  flex: 1;
  font-weight: 500;
}

.deck-checkbox .deck-count {
  color: var(--color-text-light);
  font-size: 0.875rem;
}

.session-options {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  margin-bottom: 1.5rem;
}

.session-options .option-row {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.session-options select {
  padding: 0.5rem;
  border: 1px solid var(--color-answer-border);
  border-radius: var(--radius-sm);
  background: var(--color-bg);
}

.session-summary {
  text-align: center;
  color: var(--color-text-light);
  font-size: 0.9rem;
  margin: 0 0 1.5rem 0;
}

.start-session-btn {
  display: block;
  width: 100%;
  padding: 1rem 2rem;
  background: var(--color-primary);
  color: white;
  border: none;
  border-radius: var(--radius-md);
  font-size: 1.125rem;
  font-weight: 500;
  cursor: pointer;
  transition: background var(--transition-fast);
}

.start-session-btn:hover:not(:disabled) {
  background: var(--color-primary-hover);
}

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

/* Active Study */
.active-study {
  position: relative;
}

.active-study[hidden] {
  display: none;
}

.study-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1rem;
}

.end-session-btn {
  background: transparent;
  border: 1px solid var(--color-answer-border);
  padding: 0.5rem 1rem;
  border-radius: var(--radius-sm);
  font-size: 0.875rem;
  color: var(--color-text-light);
  transition: background var(--transition-fast), color var(--transition-fast);
}

.end-session-btn:hover {
  background: var(--color-danger);
  border-color: var(--color-danger);
  color: white;
}

.study-header #fullscreen-btn {
  background: var(--color-bg);
  border: 1px solid var(--color-answer-border);
  padding: 0.5rem 0.75rem;
  border-radius: var(--radius-sm);
  font-size: 1rem;
}

.study-header #fullscreen-btn:hover {
  background: var(--color-answer-box);
}

/* Note text (renamed from comment) */
.note-text {
  color: var(--color-text-light);
  font-style: italic;
  margin: 0;
}

/* Fullscreen updates for active study */
.fullscreen-mode .study-header #fullscreen-btn,
.fullscreen-mode .study-header .end-session-btn {
  background: rgba(255, 255, 255, 0.95);
  box-shadow: var(--shadow-sm);
}

.fullscreen-mode .star-toggle {
  position: fixed;
  top: 1rem;
  right: 5rem;
  z-index: 1010;
  font-size: 2rem;
  background: transparent;
  padding: 0.5rem;
}

/* Responsive adjustments */
@media (max-width: 600px) {
  .deck-management {
    flex-direction: column;
    align-items: stretch;
    gap: 0.75rem;
  }

  .deck-selector {
    flex-direction: column;
    align-items: stretch;
  }

  .deck-selector select {
    width: 100%;
  }

  .deck-actions {
    justify-content: center;
  }

  .session-setup {
    padding: 1rem;
  }

  .session-setup h2 {
    font-size: 1.25rem;
  }

  .study-header {
    flex-wrap: wrap;
    gap: 0.5rem;
  }
}

/* Import Modal */
.import-modal {
  border: none;
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  max-width: 400px;
  width: 90%;
  box-shadow: var(--shadow-lg);
}

.import-modal::backdrop {
  background: rgba(0, 0, 0, 0.5);
}

.import-modal h2 {
  margin: 0 0 1rem;
  font-size: 1.25rem;
  color: var(--color-text);
}

.import-file-name {
  font-weight: 500;
  color: var(--color-text);
  margin: 0 0 0.25rem;
}

.import-card-count {
  color: var(--color-text-light);
  margin: 0 0 1.5rem;
  font-size: 0.875rem;
}

.import-options {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  margin-bottom: 1rem;
}

.import-option {
  padding: 1rem;
  border: 2px solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-bg);
  font-size: 1rem;
  cursor: pointer;
  transition: all 0.15s ease;
  text-align: left;
}

.import-option:hover {
  border-color: var(--color-primary);
  background: var(--color-bg-alt);
}

.import-option:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(90, 90, 90, 0.2);
}

.import-cancel {
  width: 100%;
  padding: 0.75rem;
  border: none;
  border-radius: var(--radius-md);
  background: transparent;
  color: var(--color-text-light);
  font-size: 0.875rem;
  cursor: pointer;
}

.import-cancel:hover {
  background: var(--color-bg-alt);
}

/* Share Modal */
.share-modal,
.shared-import-modal {
  border: none;
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  max-width: 500px;
  width: 90%;
  box-shadow: var(--shadow-lg);
}

.share-modal::backdrop,
.shared-import-modal::backdrop {
  background: rgba(0, 0, 0, 0.5);
}

.share-deck-name,
.shared-deck-name {
  font-weight: 500;
  color: var(--color-text);
  margin: 0 0 1rem;
}

.shared-card-count {
  color: var(--color-text-light);
  margin: 0 0 1.5rem;
  font-size: 0.875rem;
}

.share-link-container {
  display: flex;
  gap: 0.5rem;
  margin-bottom: 0.75rem;
}

.share-link-container input {
  flex: 1;
  padding: 0.75rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  font-size: 0.875rem;
  background: var(--color-bg-alt);
}

#copy-link-btn {
  padding: 0.75rem 1rem;
  background: var(--color-primary);
  color: white;
  border: none;
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-weight: 500;
}

#copy-link-btn:hover {
  background: var(--color-text);
}

.share-note {
  font-size: 0.75rem;
  color: var(--color-text-light);
  margin: 0 0 1rem;
}

.share-close {
  width: 100%;
  padding: 0.75rem;
  background: var(--color-bg-alt);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  cursor: pointer;
}

.share-close:hover {
  background: var(--color-border);
}

.shared-import-actions {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

/* Toast Notification */
.toast {
  position: fixed;
  bottom: 2rem;
  left: 50%;
  transform: translateX(-50%);
  background: var(--color-text);
  color: white;
  padding: 0.75rem 1.5rem;
  border-radius: var(--radius-md);
  font-size: 0.875rem;
  z-index: 2000;
  opacity: 0;
  transition: opacity 0.3s ease;
}

.toast:not([hidden]) {
  opacity: 1;
}

.toast.success {
  background: #2e7d32;
}

.toast.error {
  background: #c62828;
}

/* Install Banner */
.install-banner {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  background: var(--color-primary);
  color: white;
  padding: 1rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  z-index: 2000;
  box-shadow: 0 -2px 10px rgba(0, 0, 0, 0.2);
}

.install-banner[hidden] {
  display: none;
}

.install-banner p {
  margin: 0;
  font-weight: 500;
}

.install-actions {
  display: flex;
  gap: 0.5rem;
  flex-shrink: 0;
}

.install-btn {
  background: white;
  color: var(--color-primary);
  border: none;
  padding: 0.5rem 1.25rem;
  border-radius: var(--radius-sm);
  font-weight: 600;
  cursor: pointer;
}

.install-btn:hover {
  background: #f0f0f0;
}

.dismiss-btn {
  background: transparent;
  color: white;
  border: 1px solid rgba(255, 255, 255, 0.5);
  padding: 0.5rem 1rem;
  border-radius: var(--radius-sm);
  cursor: pointer;
}

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

@media (max-width: 480px) {
  .install-banner {
    flex-direction: column;
    text-align: center;
  }
}

/* Print Container (hidden on screen) */
.print-container {
  display: none;
}

/* Print styles */
@media print {
  /* Hide everything except print container */
  body > *:not(.print-container) {
    display: none !important;
  }

  .print-container {
    display: block !important;
  }

  .print-container[hidden] {
    display: block !important;
  }

  .print-title {
    text-align: center;
    font-size: 18pt;
    margin-bottom: 20pt;
    color: #333;
  }

  .print-cards {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 12pt;
  }

  .print-card {
    border: 1pt solid #ccc;
    border-radius: 6pt;
    padding: 12pt;
    page-break-inside: avoid;
    min-height: 120pt;
    display: flex;
    flex-direction: column;
  }

  .print-card-front {
    font-size: 14pt;
    font-weight: bold;
    color: #333;
    margin-bottom: 8pt;
    padding-bottom: 8pt;
    border-bottom: 1pt dashed #ddd;
  }

  .print-card-back {
    font-size: 12pt;
    color: #555;
    flex: 1;
  }

  .print-card-note {
    font-size: 9pt;
    color: #888;
    font-style: italic;
    margin-top: 8pt;
  }

  .print-card.starred {
    border-color: #ffc107;
    border-width: 2pt;
  }

  .print-card.starred::before {
    content: "★";
    position: absolute;
    top: 4pt;
    right: 8pt;
    color: #ffc107;
    font-size: 10pt;
  }

  @page {
    margin: 0.5in;
  }
}