/* Global CSS Variables & Theme Configuration */
:root {
  --font-logo: 'Outfit', sans-serif;
  --font-body: 'Inter', sans-serif;
  
  /* Dark Mode Colors (Default) */
  --bg-app: #090d16;
  --bg-gradient: linear-gradient(135deg, #090d16 0%, #111827 100%);
  --bg-panel: rgba(17, 24, 39, 0.7);
  --bg-card: rgba(31, 41, 55, 0.5);
  --bg-control: #1f2937;
  --border-color: rgba(255, 255, 255, 0.08);
  --text-main: #f3f4f6;
  --text-muted: #9ca3af;
  --text-highlight: #ffffff;
  
  /* Accents */
  --color-primary: #3b82f6; /* Sapphire Blue */
  --color-primary-hover: #2563eb;
  --color-primary-glow: rgba(59, 130, 246, 0.2);
  --color-success: #10b981; /* Emerald Green */
  --color-success-bg: rgba(16, 185, 129, 0.1);
  --color-danger: #ef4444; /* Coral Red */
  --color-danger-bg: rgba(239, 68, 68, 0.1);
  --color-warning: #f59e0b; /* Amber */
  --color-warning-bg: rgba(245, 158, 11, 0.1);
  
  --shadow-lg: 0 10px 25px -5px rgba(0, 0, 0, 0.3), 0 8px 10px -6px rgba(0, 0, 0, 0.3);
  --glass-blur: blur(16px);
  --border-radius: 12px;
  --transition-smooth: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

/* Light Mode Override */
body.light-theme {
  --bg-app: #f8fafc;
  --bg-gradient: linear-gradient(135deg, #f8fafc 0%, #f1f5f9 100%);
  --bg-panel: rgba(255, 255, 255, 0.85);
  --bg-card: #ffffff;
  --bg-control: #f1f5f9;
  --border-color: rgba(0, 0, 0, 0.08);
  --text-main: #0f172a;
  --text-muted: #64748b;
  --text-highlight: #000000;
  
  --color-primary-glow: rgba(59, 130, 246, 0.1);
  --shadow-lg: 0 10px 25px -5px rgba(0, 0, 0, 0.05), 0 8px 10px -6px rgba(0, 0, 0, 0.05);
}

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

body {
  font-family: var(--font-body);
  background: var(--bg-app);
  background-image: var(--bg-gradient);
  color: var(--text-main);
  height: 100vh;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  transition: background-color 0.3s ease, color 0.3s ease;
}

/* Header bar styling */
.app-header {
  height: 70px;
  background: var(--bg-panel);
  backdrop-filter: var(--glass-blur);
  border-bottom: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 24px;
  z-index: 100;
}

.header-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-logo);
  font-size: 22px;
  font-weight: 700;
  letter-spacing: -0.5px;
}

.logo-icon {
  color: var(--color-primary);
  font-size: 24px;
}

.logo-text span {
  font-weight: 300;
  color: var(--text-muted);
  margin-left: 2px;
}

/* Section selector tabs */
.nav-sections {
  display: flex;
  gap: 8px;
  height: 100%;
  align-items: center;
}

.nav-btn {
  background: transparent;
  border: none;
  color: var(--text-muted);
  padding: 10px 16px;
  border-radius: var(--border-radius);
  font-family: var(--font-logo);
  font-size: 15px;
  font-weight: 500;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 8px;
  transition: var(--transition-smooth);
}

.nav-btn:hover {
  color: var(--text-main);
  background: rgba(255, 255, 255, 0.03);
}

body.light-theme .nav-btn:hover {
  background: rgba(0, 0, 0, 0.03);
}

.nav-btn.active {
  color: var(--color-primary);
  background: var(--color-primary-glow);
}

.icon-btn {
  background: var(--bg-control);
  border: 1px solid var(--border-color);
  color: var(--text-main);
  width: 40px;
  height: 40px;
  border-radius: 50%;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: var(--transition-smooth);
}

.icon-btn:hover {
  transform: scale(1.05);
  border-color: var(--color-primary);
}

/* App Container and Grid Layout */
.app-container {
  flex: 1;
  display: flex;
  overflow: hidden;
  position: relative;
}

/* Sidebar Styling */
.app-sidebar {
  width: 320px;
  background: var(--bg-panel);
  backdrop-filter: var(--glass-blur);
  border-right: 1px solid var(--border-color);
  display: flex;
  flex-direction: column;
  padding: 20px;
  gap: 20px;
  overflow: hidden;
  transition: var(--transition-smooth);
}

/* Mode selector segmented button group */
.mode-selector {
  display: flex;
  background: var(--bg-control);
  padding: 4px;
  border-radius: 10px;
  border: 1px solid var(--border-color);
}

.mode-btn {
  flex: 1;
  background: transparent;
  border: none;
  color: var(--text-muted);
  font-family: var(--font-logo);
  font-size: 13px;
  font-weight: 600;
  padding: 8px 0;
  border-radius: 8px;
  cursor: pointer;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
  transition: var(--transition-smooth);
}

.mode-btn i {
  font-size: 14px;
}

.mode-btn.active {
  background: var(--bg-card);
  color: var(--text-main);
  box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
}

.sidebar-scroll-container {
  flex: 1;
  overflow-y: auto;
  padding-right: 4px;
}

/* Custom Scrollbar */
.sidebar-scroll-container::-webkit-scrollbar,
.passage-box::-webkit-scrollbar {
  width: 6px;
}
.sidebar-scroll-container::-webkit-scrollbar-track,
.passage-box::-webkit-scrollbar-track {
  background: transparent;
}
.sidebar-scroll-container::-webkit-scrollbar-thumb,
.passage-box::-webkit-scrollbar-thumb {
  background: var(--border-color);
  border-radius: 3px;
}

.sidebar-panel {
  display: flex;
  flex-direction: column;
  gap: 15px;
}

.panel-title {
  font-family: var(--font-logo);
  font-size: 16px;
  font-weight: 600;
  color: var(--text-highlight);
}

.search-box {
  display: flex;
  align-items: center;
  background: var(--bg-control);
  border: 1px solid var(--border-color);
  padding: 8px 12px;
  border-radius: 8px;
  gap: 8px;
}

.search-box i {
  color: var(--text-muted);
  font-size: 14px;
}

.search-box input {
  background: transparent;
  border: none;
  color: var(--text-main);
  outline: none;
  font-size: 14px;
  width: 100%;
}

/* Test Item Selection List */
.test-item-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.test-item {
  padding: 12px;
  background: rgba(255, 255, 255, 0.02);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  cursor: pointer;
  font-size: 14px;
  font-weight: 500;
  display: flex;
  justify-content: space-between;
  align-items: center;
  transition: var(--transition-smooth);
}

.test-item-title {
  display: flex;
  align-items: center;
  gap: 8px;
}

.completed-icon {
  color: #34d399;
  font-size: 13px;
}

body.light-theme .test-item {
  background: rgba(0, 0, 0, 0.01);
}

.test-item:hover {
  background: var(--bg-control);
  border-color: var(--color-primary);
  padding-left: 16px;
}

.test-item.active {
  background: var(--color-primary-glow);
  border-color: var(--color-primary);
  color: var(--text-highlight);
}

.test-badge {
  font-size: 10px;
  background: var(--bg-control);
  padding: 2px 6px;
  border-radius: 4px;
  border: 1px solid var(--border-color);
  color: var(--text-muted);
}

/* SRS Dashboard panel styling */
.srs-stats-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius);
  padding: 16px;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.stat-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 14px;
}

.stat-label {
  color: var(--text-muted);
  font-weight: 500;
}

.stat-val {
  font-weight: 700;
  font-size: 15px;
  padding: 2px 8px;
  border-radius: 4px;
}

.count-new {
  color: #60a5fa;
  background: rgba(96, 165, 250, 0.1);
}

.count-due {
  color: #f87171;
  background: rgba(248, 113, 113, 0.1);
}

.count-learning {
  color: #fbbf24;
  background: rgba(251, 191, 36, 0.1);
}

/* Card Display Panel (Main Card view) */
.card-display-panel {
  flex: 1;
  display: flex;
  flex-direction: column;
  padding: 24px;
  gap: 20px;
  overflow: hidden;
  background: rgba(0, 0, 0, 0.15);
}

body.light-theme .card-display-panel {
  background: rgba(0, 0, 0, 0.02);
}

/* Progress bar */
.progress-bar-container {
  display: flex;
  flex-direction: column;
  gap: 8px;
  width: 100%;
}

.progress-text {
  font-size: 13px;
  color: var(--text-muted);
  font-weight: 500;
  align-self: flex-end;
}

.progress-track {
  height: 6px;
  background: var(--bg-control);
  border-radius: 3px;
  width: 100%;
  overflow: hidden;
}

.progress-fill {
  height: 100%;
  background: var(--color-primary);
  border-radius: 3px;
  width: 0%;
  transition: width 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

/* Card container glass panel */
.question-card {
  flex: 1;
  background: var(--bg-panel);
  backdrop-filter: var(--glass-blur);
  border: 1px solid var(--border-color);
  border-radius: 20px;
  padding: 30px;
  display: flex;
  flex-direction: column;
  overflow-y: auto;
  box-shadow: var(--shadow-lg);
  position: relative; /* Fixed: relative container for absolute loading layout */
}

.card-screen {
  display: flex;
  flex-direction: column;
  height: 100%;
}

/* Screens states */
#welcome-screen {
  justify-content: center;
  align-items: center;
  text-align: center;
  gap: 16px;
  max-width: 500px;
  margin: 0 auto;
}

.welcome-graphic {
  width: 100px;
  height: 100px;
  background: var(--color-primary-glow);
  color: var(--color-primary);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 44px;
  margin-bottom: 10px;
  animation: pulse 2s infinite;
}

#welcome-screen h2 {
  font-family: var(--font-logo);
  font-size: 26px;
  font-weight: 700;
}

#welcome-screen p {
  color: var(--text-muted);
  font-size: 15px;
  line-height: 1.6;
}

/* Spinner Overlay (Absolute to prevent layout shift) */
#loading-screen {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: var(--bg-panel);
  backdrop-filter: var(--glass-blur);
  display: flex;
  justify-content: center;
  align-items: center;
  flex-direction: column;
  gap: 16px;
  z-index: 10;
  border-radius: 20px;
}

.spinner {
  width: 50px;
  height: 50px;
  border: 4px solid var(--border-color);
  border-top-color: var(--color-primary);
  border-radius: 50%;
  animation: spin 1s linear infinite;
}

/* Active Question Elements */
.card-meta {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 20px;
}

.card-meta-actions {
  display: flex;
  align-items: center;
  gap: 10px;
}

.meta-action-btn {
  background: var(--bg-control);
  border: 1px solid var(--border-color);
  color: var(--text-muted);
  padding: 6px 12px;
  border-radius: var(--border-radius);
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  transition: var(--transition-smooth);
}

.meta-action-btn:hover {
  border-color: var(--color-primary);
  color: var(--text-main);
  background: var(--color-primary-glow);
}

.meta-action-btn.active {
  background: rgba(52, 211, 153, 0.1);
  border-color: var(--color-success);
  color: #34d399;
}

.meta-action-btn.active:hover {
  background: rgba(52, 211, 153, 0.15);
  color: #34d399;
}

.card-origin-tag {
  font-size: 13px;
  font-weight: 600;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.card-srs-badge {
  font-size: 11px;
  font-weight: 700;
  padding: 4px 10px;
  border-radius: 20px;
  text-transform: uppercase;
}

/* Passage content styling */
.passage-box {
  background: rgba(255, 255, 255, 0.02);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius);
  padding: 20px;
  margin-bottom: 20px;
  font-size: 18px;
  line-height: 1.7;
  max-height: 250px;
  overflow-y: auto;
  white-space: pre-wrap;
}

body.light-theme .passage-box {
  background: rgba(0, 0, 0, 0.01);
}

.question-prompt {
  font-family: var(--font-logo);
  font-size: 24px;
  font-weight: 600;
  margin-bottom: 24px;
  color: var(--text-highlight);
  line-height: 1.4;
}

/* Choices list layout */
.choices-list {
  display: grid;
  grid-template-columns: 1fr;
  gap: 12px;
}

.choice-btn {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  color: var(--text-main);
  padding: 18px 20px;
  border-radius: var(--border-radius);
  cursor: pointer;
  display: flex;
  align-items: center;
  font-size: 18px;
  text-align: left;
  transition: var(--transition-smooth);
}

.choice-btn:hover {
  background: var(--bg-control);
  border-color: var(--color-primary);
  transform: translateY(-1px);
}

.choice-letter {
  font-weight: 700;
  margin-right: 12px;
  width: 24px;
  height: 24px;
  background: rgba(255, 255, 255, 0.06);
  border-radius: 50%;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 13px;
}

/* Active states for Exam mode selection */
.choice-btn.selected {
  border-color: var(--color-primary);
  background: var(--color-primary-glow);
}

.choice-btn.correct {
  border-color: var(--color-success);
  background: var(--color-success-bg);
  color: #34d399;
}

.choice-btn.wrong {
  border-color: var(--color-danger);
  background: var(--color-danger-bg);
  color: #f87171;
}

/* Placeholder choices (Correction mode) */
.choice-btn.placeholder {
  opacity: 0.5;
  cursor: not-allowed;
  background: var(--bg-card);
  border: 1px dashed var(--border-color);
  transform: none;
}

.choice-btn.placeholder:hover {
  background: var(--bg-card);
  border-color: var(--border-color);
  transform: none;
}

.placeholder-bar {
  display: inline-block;
  height: 10px;
  width: 120px;
  background: var(--text-main);
  border-radius: 4px;
  opacity: 0.15;
  margin-left: 4px;
}

/* Listening Audio Box */
.audio-player-box {
  margin: 10px 0 24px 0;
  width: 100%;
}

.audio-player-box audio {
  width: 100%;
  border-radius: 30px;
  outline: none;
}

/* Text response areas (writing prompts) */
.response-draft-box {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-bottom: 20px;
}

.input-label {
  font-size: 14px;
  font-weight: 600;
  color: var(--text-muted);
}

.response-draft-box textarea {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius);
  color: var(--text-main);
  padding: 16px;
  font-size: 16px;
  line-height: 1.6;
  outline: none;
  resize: vertical;
  transition: var(--transition-smooth);
}

.response-draft-box textarea:focus {
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px var(--color-primary-glow);
}

.word-counter {
  font-size: 13px;
  color: var(--text-muted);
  align-self: flex-end;
  font-weight: 500;
}

/* Speaking Recording Box */
.speaking-box {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 15px;
  padding: 30px;
  background: rgba(255, 255, 255, 0.01);
  border: 1px dashed var(--border-color);
  border-radius: var(--border-radius);
  margin-bottom: 24px;
}

.speaking-timer {
  font-family: var(--font-logo);
  font-size: 32px;
  font-weight: 700;
  letter-spacing: 1px;
}

.record-btn {
  width: 70px;
  height: 70px;
  background: var(--color-danger-bg);
  border: 2px solid var(--color-danger);
  color: var(--color-danger);
  border-radius: 50%;
  cursor: pointer;
  font-size: 26px;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: var(--transition-smooth);
}

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

.record-btn.recording {
  background: var(--color-danger);
  color: #ffffff;
  animation: pulse 1.5s infinite;
}

.record-status {
  font-size: 13px;
  color: var(--text-muted);
  font-weight: 500;
}

/* Correction Explanation Panel */
.correction-box {
  background: rgba(255, 255, 255, 0.02);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius);
  padding: 20px;
  margin-top: 20px;
  font-size: 16px;
  line-height: 1.6;
}

.correction-box-title {
  font-family: var(--font-logo);
  font-size: 16px;
  font-weight: 600;
  color: var(--color-success);
  margin-bottom: 10px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.sample-answer-text {
  font-size: 16px;
  line-height: 1.7;
  white-space: pre-wrap;
}

/* Controls Bar (Footer Actions) */
.controls-bar {
  height: 60px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

/* Styled utility buttons */
.action-btn {
  padding: 12px 24px;
  border-radius: 30px;
  font-family: var(--font-logo);
  font-size: 15px;
  font-weight: 600;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 8px;
  border: none;
  transition: var(--transition-smooth);
}

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

.primary-btn:hover {
  background: var(--color-primary-hover);
  box-shadow: 0 0 15px var(--color-primary-glow);
}

.secondary-btn {
  background: var(--bg-control);
  border: 1px solid var(--border-color);
  color: var(--text-main);
}

.secondary-btn:hover {
  background: var(--bg-card);
  border-color: var(--text-muted);
}

.wide-btn {
  width: 100%;
  justify-content: center;
  padding: 14px;
  font-size: 15px;
}

.margin-top-sm {
  margin-top: 8px;
}

.hidden {
  display: none !important;
}

/* SRS Rating Buttons container */
.srs-rating-box {
  display: flex;
  gap: 10px;
}

.rating-btn {
  border: none;
  border-radius: 30px;
  padding: 8px 16px;
  cursor: pointer;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  font-family: var(--font-logo);
  transition: var(--transition-smooth);
  min-width: 90px;
}

.rate-again {
  background: var(--color-danger-bg);
  border: 1px solid var(--color-danger);
  color: #f87171;
}
.rate-again:hover {
  background: var(--color-danger);
  color: white;
}

.rate-hard {
  background: var(--color-warning-bg);
  border: 1px solid var(--color-warning);
  color: #fbbf24;
}
.rate-hard:hover {
  background: var(--color-warning);
  color: white;
}

.rate-good {
  background: var(--color-primary-glow);
  border: 1px solid var(--color-primary);
  color: #60a5fa;
}
.rate-good:hover {
  background: var(--color-primary);
  color: white;
}

.rate-easy {
  background: var(--color-success-bg);
  border: 1px solid var(--color-success);
  color: #34d399;
}
.rate-easy:hover {
  background: var(--color-success);
  color: white;
}

.rate-label {
  font-size: 13px;
  font-weight: 700;
}
.rate-desc {
  font-size: 9px;
  margin-top: 2px;
  opacity: 0.8;
}

/* Keyframe animations */
@keyframes spin {
  from { transform: rotate(0deg); }
  to { transform: rotate(360deg); }
}

@keyframes pulse {
  0% { transform: scale(1); box-shadow: 0 0 0 0 rgba(239, 68, 68, 0.4); }
  70% { transform: scale(1.03); box-shadow: 0 0 0 10px rgba(239, 68, 68, 0); }
  100% { transform: scale(1); box-shadow: 0 0 0 0 rgba(239, 68, 68, 0); }
}

/* Desktop vs Mobile Responsiveness */
.mobile-back-btn {
  display: none; /* Hide on desktop */
}

@media (max-width: 900px) {
  body {
    overflow: hidden; /* Keep the app layout structure fixed on mobile */
    height: 100vh;
  }

  /* Grid-based premium header */
  .app-header {
    display: grid;
    grid-template-columns: 1fr auto;
    grid-template-areas: 
      "logo actions"
      "nav nav";
    height: auto;
    padding: 10px 16px;
    gap: 8px;
  }
  
  .header-logo {
    grid-area: logo;
    align-self: center;
  }
  
  .header-actions {
    grid-area: actions;
    align-self: center;
  }
  
  .nav-sections {
    grid-area: nav;
    width: 100%;
    overflow-x: auto;
    padding-bottom: 4px;
    justify-content: flex-start;
    gap: 4px;
  }
  
  .nav-btn {
    white-space: nowrap;
    padding: 8px 12px;
    font-size: 13px;
  }
  
  /* Container layout - split screen views on mobile */
  .app-container {
    flex-direction: column;
    overflow: hidden;
    height: 100%;
    position: relative;
  }
  
  /* Show sidebar / hide card panel when sidebar is active */
  .app-container.sidebar-active .app-sidebar {
    display: flex;
    width: 100%;
    height: 100%;
    border-right: none;
    padding: 15px;
    overflow: hidden;
  }
  .app-container.sidebar-active .card-display-panel {
    display: none !important;
  }
  
  /* Hide sidebar / show card panel when test/card is active */
  .app-container:not(.sidebar-active) .app-sidebar {
    display: none !important;
  }
  .app-container:not(.sidebar-active) .card-display-panel {
    display: flex;
    width: 100%;
    height: 100%;
    padding: 12px;
    gap: 12px;
    overflow: hidden;
  }
  
  /* Mobile back button styling */
  .mobile-back-btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    background: var(--bg-control);
    border: 1px solid var(--border-color);
    color: var(--text-main);
    padding: 8px 16px;
    border-radius: 20px;
    font-family: var(--font-logo);
    font-size: 13px;
    font-weight: 600;
    cursor: pointer;
    margin-bottom: 4px;
    align-self: flex-start;
    transition: var(--transition-smooth);
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
  }
  
  .mobile-back-btn:hover {
    background: var(--bg-card);
    border-color: var(--color-primary);
  }
  
  /* Card container optimizations */
  .question-card {
    padding: 20px;
    border-radius: 16px;
    flex: 1;
    overflow-y: auto;
  }
  
  /* Optimize passage box text size & height */
  .passage-box {
    padding: 14px;
    font-size: 15px;
    line-height: 1.6;
    max-height: 180px;
    margin-bottom: 15px;
  }
  
  /* Optimize prompt font size */
  .question-prompt {
    font-size: 18px;
    margin-bottom: 16px;
  }
  
  /* Optimize choice button layout & font sizes */
  .choices-list {
    gap: 8px;
  }
  
  .choice-btn {
    padding: 12px 16px;
    font-size: 15px;
    border-radius: 10px;
  }
  
  .choice-letter {
    width: 22px;
    height: 22px;
    font-size: 12px;
    margin-right: 8px;
  }
  
  /* Sticky controls bar on mobile */
  .controls-bar {
    height: auto;
    padding: 8px 0;
    gap: 8px;
    flex-wrap: nowrap;
    justify-content: space-between;
    width: 100%;
    border-top: 1px solid var(--border-color);
  }
  
  .controls-bar .action-btn {
    padding: 8px 12px;
    font-size: 13px;
    border-radius: 20px;
    gap: 4px;
  }
  
  /* Mobile optimized SRS rating buttons to prevent overflow */
  .srs-rating-box {
    display: flex;
    gap: 4px;
    width: 100%;
    justify-content: space-between;
    order: unset;
  }
  
  .rating-btn {
    min-width: 0;
    flex: 1;
    padding: 6px 4px;
    border-radius: 12px;
  }
  
  .rate-label {
    font-size: 11px;
  }
  
  .rate-desc {
    display: none; /* Hide descriptions to fit all 4 buttons on mobile screens */
  }
}

/* Question Image Container */
.image-box {
  width: 100%;
  margin-bottom: 20px;
  display: block;
  text-align: center;
  border-radius: var(--border-radius);
  overflow: hidden;
  background: rgba(0, 0, 0, 0.05);
  border: 1px solid var(--border-color);
  flex-shrink: 0; /* Prevent layout squishing in flex containers */
}

.image-box img {
  width: 100%;
  height: auto;
  display: block;
}

/* Transcript Toggler Box at the bottom */
.transcript-box {
  margin-top: 24px;
  border-top: 1px solid var(--border-color);
  padding-top: 16px;
  width: 100%;
}

.transcript-toggle-btn {
  background: var(--bg-control);
  border: 1px solid var(--border-color);
  color: var(--text-muted);
  padding: 8px 16px;
  border-radius: var(--border-radius);
  cursor: pointer;
  font-size: 14px;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-weight: 500;
  transition: var(--transition-smooth);
}

.transcript-toggle-btn:hover {
  color: var(--color-primary);
  border-color: var(--color-primary);
  background: var(--color-primary-glow);
}

.transcript-content {
  margin-top: 12px;
  padding: 16px;
  background: rgba(255, 255, 255, 0.03);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius);
  font-size: 15px;
  line-height: 1.6;
  color: var(--text-muted);
  white-space: pre-wrap;
}
body.light-theme .transcript-content {
  background: rgba(0, 0, 0, 0.02);
}

/* ==========================================
   Cloud Sync Feature Styles (Responsive Header Modal)
   ========================================== */

/* Sync Button & Status Badge */
.sync-btn {
  position: relative;
}

.sync-badge {
  position: absolute;
  top: 2px;
  right: 2px;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  border: 1.5px solid var(--bg-panel);
  transition: var(--transition-smooth);
}

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

.sync-badge.syncing {
  background-color: var(--color-warning);
  animation: pulse 1.5s infinite ease-in-out;
}

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

.sync-badge.offline {
  background-color: #64748b;
}

/* Modal Overlay (Keyboard friendly scroll support) */
.modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.6);
  backdrop-filter: blur(8px);
  z-index: 1000;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.3s ease;
  overflow-y: auto;
  padding: 20px 10px;
}

.modal-overlay.active {
  opacity: 1;
  pointer-events: auto;
}

/* Modal Content Glassmorphic Design */
.modal-content.glass-card {
  background: var(--bg-panel);
  backdrop-filter: var(--glass-blur);
  border: 1px solid var(--border-color);
  border-radius: 20px;
  width: 100%;
  max-width: 420px;
  box-shadow: var(--shadow-lg);
  overflow: hidden;
  transform: scale(0.95) translateY(10px);
  transition: transform 0.3s cubic-bezier(0.34, 1.56, 0.64, 1), opacity 0.3s ease;
  margin: auto; /* Handles vertical centering when keyboard is active */
}

.modal-overlay.active .modal-content.glass-card {
  transform: scale(1) translateY(0);
}

.modal-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 20px 24px;
  border-bottom: 1px solid var(--border-color);
}

.modal-header h2 {
  font-family: var(--font-logo);
  font-size: 20px;
  font-weight: 600;
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--text-highlight);
  margin: 0;
}

.modal-drag-handle {
  width: 36px;
  height: 4px;
  background: var(--border-color);
  border-radius: 2px;
  margin: 12px auto 0 auto;
  display: none; /* Only visible on mobile */
}

.close-btn {
  background: var(--bg-control);
  border: 1px solid var(--border-color);
  color: var(--text-muted);
  width: 36px;
  height: 36px;
  border-radius: 50%;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: var(--transition-smooth);
  font-size: 14px;
  padding: 0;
}

.close-btn:hover {
  background: var(--bg-card);
  color: var(--color-danger);
  transform: scale(1.05);
}

.modal-body {
  padding: 24px;
}

.modal-desc {
  font-size: 14px;
  color: var(--text-muted);
  line-height: 1.5;
  margin-bottom: 20px;
}

/* Tabs - Premium Segmented Control */
.sync-tabs {
  display: flex;
  background: var(--bg-control);
  padding: 4px;
  border-radius: 12px;
  border: 1px solid var(--border-color);
  margin-bottom: 24px;
}

.sync-tab-btn {
  flex: 1;
  background: transparent;
  border: none;
  color: var(--text-muted);
  padding: 10px 0;
  font-family: var(--font-logo);
  font-size: 14px;
  font-weight: 600;
  border-radius: 8px;
  cursor: pointer;
  transition: var(--transition-smooth);
  text-align: center;
}

.sync-tab-btn.active {
  background: var(--bg-card);
  color: var(--text-highlight);
  box-shadow: var(--shadow-sm);
}

.sync-tab-btn:hover:not(.active) {
  color: var(--text-main);
}

/* Form Styles */
.sync-form {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.form-group label {
  font-size: 13px;
  font-weight: 500;
  color: var(--text-main);
}

.form-group input {
  background: var(--bg-control);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius);
  color: var(--text-main);
  padding: 12px 16px;
  font-family: var(--font-body);
  font-size: 14px;
  outline: none;
  transition: var(--transition-smooth);
  width: 100%;
}

.form-group input:focus {
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px var(--color-primary-glow);
}

.auth-error-msg {
  background: var(--color-danger-bg);
  border: 1px solid var(--color-danger);
  color: var(--color-danger);
  padding: 10px 12px;
  border-radius: var(--border-radius);
  font-size: 13px;
  line-height: 1.4;
}

.auth-success-msg {
  background: var(--color-success-bg);
  border: 1px solid var(--color-success);
  color: var(--color-success);
  padding: 10px 12px;
  border-radius: var(--border-radius);
  font-size: 13px;
  line-height: 1.4;
}

/* Authenticated UI Cards */
.user-status-card {
  display: flex;
  align-items: center;
  gap: 16px;
  background: var(--bg-card);
  padding: 16px;
  border-radius: var(--border-radius);
  border: 1px solid var(--border-color);
  margin-bottom: 20px;
}

.user-avatar {
  font-size: 36px;
  color: var(--color-primary);
}

.user-info {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.user-email {
  font-weight: 600;
  font-size: 15px;
  color: var(--text-highlight);
  word-break: break-all;
}

.sync-status-text {
  font-size: 12px;
  color: var(--color-success);
}

/* Stats Summary */
.sync-stats-summary {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  margin-bottom: 24px;
}

.sync-stat-item {
  background: var(--bg-control);
  border: 1px solid var(--border-color);
  padding: 12px;
  border-radius: var(--border-radius);
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.sync-stat-item .label {
  font-size: 10px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: var(--text-muted);
}

.sync-stat-item .value {
  font-size: 14px;
  font-weight: 600;
  color: var(--text-highlight);
}

.btn-spinner {
  width: 16px;
  height: 16px;
  border: 2px solid rgba(255, 255, 255, 0.2);
  border-radius: 50%;
  border-top-color: #fff;
  animation: spin 0.8s linear infinite;
  display: inline-block;
  vertical-align: middle;
  margin-left: 8px;
}

/* Mobile responsive modal styling */
@media (max-width: 600px) {
  .modal-overlay {
    align-items: flex-end; /* Align bottom sheet to the bottom of the screen */
    padding: 0;
  }

  .modal-drag-handle {
    display: block;
  }

  .modal-content.glass-card {
    max-width: 100%;
    width: 100%;
    border-radius: 24px 24px 0 0;
    margin: 0;
    border-left: none;
    border-right: none;
    border-bottom: none;
    max-height: 85vh;
    display: flex;
    flex-direction: column;
    transform: translateY(100%);
    box-shadow: 0 -10px 25px rgba(0, 0, 0, 0.2);
  }

  .modal-overlay.active .modal-content.glass-card {
    transform: translateY(0);
  }

  .modal-header {
    padding: 12px 20px 16px 20px;
  }

  .modal-body {
    padding: 20px;
    overflow-y: auto;
    -webkit-overflow-scrolling: touch;
    flex: 1;
    padding-bottom: calc(30px + env(safe-area-inset-bottom));
  }

  .form-group input {
    font-size: 16px; /* Prevents auto-zoom on iOS Safari */
  }

  .sync-stats-summary {
    grid-template-columns: 1fr;
    gap: 8px;
  }
}

/* Keyframe animations */
@keyframes pulse {
  0% { transform: scale(1); opacity: 1; }
  50% { transform: scale(1.15); opacity: 0.7; }
  100% { transform: scale(1); opacity: 1; }
}