/* ===================================================================
   StudyPulse Design System & Styles
   Modern, glassmorphic, responsive study buddy application
   =================================================================== */

:root {
  /* Color Palette - Dark Mode (Default) */
  --bg-primary: #090d16;
  --bg-secondary: #0f172a;
  --bg-card: rgba(30, 41, 59, 0.7);
  --bg-card-hover: rgba(51, 65, 85, 0.8);
  --bg-elevated: #1e293b;
  --bg-glass: rgba(15, 23, 42, 0.75);
  
  --text-primary: #f8fafc;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  
  --accent-primary: #6366f1;
  --accent-primary-hover: #4f46e5;
  --accent-gradient: linear-gradient(135deg, #6366f1 0%, #8b5cf6 50%, #ec4899 100%);
  --accent-glow: rgba(99, 102, 241, 0.25);
  
  --color-work: #6366f1;
  --color-work-glow: rgba(99, 102, 241, 0.35);
  --color-short-break: #10b981;
  --color-short-glow: rgba(16, 185, 129, 0.35);
  --color-long-break: #06b6d4;
  --color-long-glow: rgba(6, 182, 212, 0.35);
  
  --color-success: #10b981;
  --color-warning: #f59e0b;
  --color-danger: #ef4444;
  
  --border-subtle: rgba(255, 255, 255, 0.08);
  --border-strong: rgba(255, 255, 255, 0.16);
  --border-focus: rgba(99, 102, 241, 0.5);
  
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.2);
  --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.35);
  --shadow-lg: 0 16px 40px rgba(0, 0, 0, 0.5);
  --shadow-glow: 0 0 30px var(--accent-glow);
  
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;
  --radius-full: 9999px;
  
  --font-heading: 'Outfit', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-body: 'Plus Jakarta Sans', -apple-system, BlinkMacSystemFont, sans-serif;
  
  --transition-fast: 0.15s ease;
  --transition-normal: 0.25s ease;
  --transition-smooth: 0.4s cubic-bezier(0.16, 1, 0.3, 1);
}

/* Light Theme Variables */
body.theme-light {
  --bg-primary: #f8fafc;
  --bg-secondary: #ffffff;
  --bg-card: rgba(255, 255, 255, 0.85);
  --bg-card-hover: rgba(241, 245, 249, 0.95);
  --bg-elevated: #ffffff;
  --bg-glass: rgba(255, 255, 255, 0.8);
  
  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-muted: #94a3b8;
  
  --border-subtle: rgba(0, 0, 0, 0.08);
  --border-strong: rgba(0, 0, 0, 0.14);
  --border-focus: rgba(99, 102, 241, 0.5);
  
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.04);
  --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 16px 40px rgba(0, 0, 0, 0.12);
  --shadow-glow: 0 0 25px rgba(99, 102, 241, 0.15);
}

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

body {
  font-family: var(--font-body);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  min-height: 100vh;
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
  background-image: 
    radial-gradient(at 0% 0%, rgba(99, 102, 241, 0.12) 0px, transparent 50%),
    radial-gradient(at 100% 100%, rgba(236, 72, 153, 0.08) 0px, transparent 50%);
  background-attachment: fixed;
  overflow-x: hidden;
  transition: background-color var(--transition-normal), color var(--transition-normal);
}

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

/* Layout */
.app-layout {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 20px 40px;
}

/* Header */
.app-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 20px 0;
  border-bottom: 1px solid var(--border-subtle);
  position: sticky;
  top: 0;
  background: var(--bg-glass);
  backdrop-filter: blur(12px);
  z-index: 100;
}

.logo {
  display: flex;
  align-items: center;
  gap: 12px;
}

.logo-icon {
  width: 42px;
  height: 42px;
  background: var(--accent-gradient);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  box-shadow: 0 4px 16px rgba(99, 102, 241, 0.35);
  animation: pulseLogo 3s ease-in-out infinite;
}

@keyframes pulseLogo {
  0%, 100% { transform: scale(1); }
  50% { transform: scale(1.03); }
}

.logo-title {
  font-family: var(--font-heading);
  font-size: 1.35rem;
  font-weight: 800;
  letter-spacing: -0.5px;
  background: var(--accent-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  display: block;
}

.logo-tagline {
  font-size: 0.72rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 1px;
  font-weight: 600;
  display: block;
  margin-top: -3px;
}

/* Mini Timer Pill (Sticky header companion) */
.mini-timer-pill {
  display: flex;
  align-items: center;
  gap: 10px;
  background: var(--bg-card);
  border: 1px solid var(--border-strong);
  padding: 6px 14px;
  border-radius: var(--radius-full);
  backdrop-filter: blur(10px);
  box-shadow: var(--shadow-sm);
  animation: fadeIn 0.2s ease-in;
}

.mini-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--color-work);
  animation: blinkDot 1.2s infinite ease-in-out;
}

@keyframes blinkDot {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.3; }
}

.mini-mode-label {
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--text-secondary);
}

.mini-time-display {
  font-family: var(--font-heading);
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--text-primary);
  min-width: 48px;
}

.mini-btn {
  background: var(--border-subtle);
  border: none;
  color: var(--text-primary);
  width: 26px;
  height: 26px;
  border-radius: 50%;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: var(--transition-fast);
}

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

/* Header Right */
.header-right {
  display: flex;
  align-items: center;
  gap: 12px;
}

.streak-badge {
  display: flex;
  align-items: center;
  gap: 6px;
  background: rgba(245, 158, 11, 0.12);
  border: 1px solid rgba(245, 158, 11, 0.28);
  color: #f59e0b;
  padding: 6px 12px;
  border-radius: var(--radius-full);
  font-size: 0.82rem;
  font-weight: 600;
}

.streak-label {
  display: none;
}

@media (min-width: 640px) {
  .streak-label {
    display: inline;
  }
}

.icon-btn {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  color: var(--text-secondary);
  width: 38px;
  height: 38px;
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: var(--transition-fast);
}

.icon-btn:hover {
  background: var(--bg-card-hover);
  color: var(--text-primary);
  border-color: var(--border-strong);
  transform: translateY(-1px);
}

/* Ambient Sound Widget */
.ambient-widget {
  position: relative;
}

.ambient-dropdown {
  position: absolute;
  top: calc(100% + 8px);
  right: 0;
  width: 220px;
  background: var(--bg-elevated);
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-md);
  padding: 12px;
  box-shadow: var(--shadow-lg);
  display: none;
  flex-direction: column;
  gap: 10px;
  z-index: 101;
}

.ambient-dropdown.show {
  display: flex;
}

.dropdown-header {
  font-size: 0.78rem;
  font-weight: 700;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.ambient-options {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.ambient-option {
  text-align: left;
  background: transparent;
  border: none;
  color: var(--text-secondary);
  padding: 8px 10px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-size: 0.85rem;
  font-weight: 500;
  transition: var(--transition-fast);
}

.ambient-option:hover {
  background: var(--bg-card-hover);
  color: var(--text-primary);
}

.ambient-option.active {
  background: rgba(99, 102, 241, 0.16);
  color: var(--accent-primary);
  font-weight: 600;
}

.ambient-volume-control {
  display: flex;
  flex-direction: column;
  gap: 4px;
  margin-top: 4px;
  border-top: 1px solid var(--border-subtle);
  padding-top: 8px;
}

.ambient-volume-control label {
  font-size: 0.75rem;
  color: var(--text-muted);
}

.ambient-volume-control input[type="range"] {
  accent-color: var(--accent-primary);
  width: 100%;
}

/* Navigation Tabs */
.nav-tabs {
  display: flex;
  gap: 8px;
  padding: 18px 0;
  border-bottom: 1px solid var(--border-subtle);
  overflow-x: auto;
  scrollbar-width: none;
}

.nav-tabs::-webkit-scrollbar {
  display: none;
}

.nav-tab {
  display: flex;
  align-items: center;
  gap: 8px;
  background: transparent;
  border: 1px solid transparent;
  color: var(--text-secondary);
  font-family: var(--font-body);
  font-size: 0.92rem;
  font-weight: 600;
  padding: 10px 18px;
  border-radius: var(--radius-full);
  cursor: pointer;
  transition: var(--transition-normal);
  white-space: nowrap;
}

.nav-tab:hover {
  color: var(--text-primary);
  background: var(--bg-card);
}

.nav-tab.active {
  color: #fff;
  background: var(--accent-primary);
  box-shadow: 0 4px 14px var(--accent-glow);
}

.nav-tab .badge {
  background: rgba(255, 255, 255, 0.18);
  font-size: 0.72rem;
  padding: 2px 7px;
  border-radius: var(--radius-full);
}

/* Tab Panels */
.tab-panel {
  display: none;
  animation: fadeIn 0.3s ease-out;
  padding-top: 24px;
}

.tab-panel.active {
  display: block;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(6px); }
  to { opacity: 1; transform: translateY(0); }
}

/* ===================================================================
   BUTTONS & COMMON UI
   =================================================================== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  font-family: var(--font-body);
  font-size: 0.9rem;
  font-weight: 600;
  padding: 10px 18px;
  border-radius: var(--radius-md);
  border: none;
  cursor: pointer;
  transition: var(--transition-fast);
}

.btn:active {
  transform: scale(0.98);
}

.btn-primary {
  background: var(--accent-primary);
  color: #ffffff;
  box-shadow: 0 4px 14px var(--accent-glow);
}

.btn-primary:hover {
  background: var(--accent-primary-hover);
  transform: translateY(-1px);
}

.btn-secondary {
  background: var(--bg-card);
  color: var(--text-primary);
  border: 1px solid var(--border-strong);
}

.btn-secondary:hover {
  background: var(--bg-card-hover);
}

.btn-outline {
  background: transparent;
  color: var(--text-primary);
  border: 1px solid var(--border-strong);
}

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

.btn-outline-danger {
  background: transparent;
  color: var(--color-danger);
  border: 1px solid rgba(239, 68, 68, 0.3);
}

.btn-outline-danger:hover {
  background: rgba(239, 68, 68, 0.12);
  border-color: var(--color-danger);
}

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

.btn-ghost:hover {
  color: var(--text-primary);
  background: var(--bg-card);
}

.btn-large {
  padding: 14px 28px;
  font-size: 1rem;
  border-radius: var(--radius-md);
}

.btn-sm {
  padding: 6px 12px;
  font-size: 0.8rem;
}

.btn-icon-round {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  padding: 0;
  background: var(--bg-card);
  color: var(--text-primary);
  border: 1px solid var(--border-strong);
}

.btn-icon-round:hover {
  background: var(--bg-card-hover);
  border-color: var(--accent-primary);
}

/* ===================================================================
   TAB 1: POMODORO CLOCK
   =================================================================== */
.pomodoro-container {
  display: flex;
  flex-direction: column;
  align-items: center;
  max-width: 600px;
  margin: 0 auto;
  gap: 28px;
}

/* Mode Switcher */
.timer-modes-bar {
  display: flex;
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  padding: 6px;
  border-radius: var(--radius-full);
  gap: 6px;
  box-shadow: var(--shadow-sm);
}

.mode-pill {
  display: flex;
  align-items: center;
  gap: 6px;
  background: transparent;
  border: none;
  color: var(--text-secondary);
  font-family: var(--font-body);
  font-size: 0.88rem;
  font-weight: 600;
  padding: 8px 16px;
  border-radius: var(--radius-full);
  cursor: pointer;
  transition: var(--transition-fast);
}

.mode-pill:hover {
  color: var(--text-primary);
}

.mode-pill.active {
  background: var(--bg-elevated);
  color: var(--text-primary);
  box-shadow: var(--shadow-sm);
}

.mode-badge {
  font-size: 0.72rem;
  background: var(--border-subtle);
  padding: 2px 6px;
  border-radius: var(--radius-full);
  color: var(--text-muted);
}

.mode-pill.active .mode-badge {
  background: var(--border-strong);
  color: var(--text-primary);
}

/* Circular Clock */
.clock-display-wrap {
  position: relative;
  width: 320px;
  height: 320px;
  margin: 8px 0;
}

.clock-svg-box {
  width: 100%;
  height: 100%;
  position: relative;
}

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

.progress-ring__background {
  fill: transparent;
  stroke: var(--border-subtle);
}

.progress-ring__circle {
  fill: transparent;
  stroke: var(--color-work);
  stroke-linecap: round;
  stroke-dasharray: 911;
  stroke-dashoffset: 0;
  transition: stroke-dashoffset 0.8s linear, stroke var(--transition-normal);
  filter: drop-shadow(0 0 10px var(--color-work-glow));
}

.clock-inner {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  pointer-events: none;
}

.session-label {
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 1.5px;
  color: var(--text-muted);
  text-transform: uppercase;
  margin-bottom: 4px;
}

.time-countdown {
  font-family: var(--font-heading);
  font-size: 4.2rem;
  font-weight: 800;
  letter-spacing: -2px;
  line-height: 1;
  color: var(--text-primary);
  margin-bottom: 8px;
}

.session-counter-dots {
  display: flex;
  gap: 6px;
  margin-bottom: 6px;
}

.cycle-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--border-strong);
  transition: var(--transition-fast);
}

.cycle-dot.filled {
  background: var(--color-work);
  box-shadow: 0 0 8px var(--color-work-glow);
}

.session-cycle-text {
  font-size: 0.78rem;
  color: var(--text-muted);
  font-weight: 500;
}

/* Controls */
.timer-controls {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
  flex-wrap: wrap;
}

.primary-timer-btn {
  display: flex;
  align-items: center;
  gap: 10px;
  background: var(--accent-gradient);
  color: #fff;
  border: none;
  font-family: var(--font-heading);
  font-size: 1.1rem;
  font-weight: 700;
  letter-spacing: 0.5px;
  padding: 16px 36px;
  border-radius: var(--radius-full);
  cursor: pointer;
  box-shadow: 0 8px 24px var(--accent-glow);
  transition: var(--transition-smooth);
}

.primary-timer-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 12px 30px var(--accent-glow);
}

.primary-timer-btn:active {
  transform: scale(0.97);
}

.secondary-timer-btn {
  display: flex;
  align-items: center;
  gap: 6px;
  background: var(--bg-card);
  color: var(--text-primary);
  border: 1px solid var(--border-strong);
  font-family: var(--font-body);
  font-size: 0.88rem;
  font-weight: 600;
  padding: 12px 20px;
  border-radius: var(--radius-full);
  cursor: pointer;
  transition: var(--transition-fast);
}

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

.adjust-time-btn {
  background: transparent;
  color: var(--text-muted);
  border: 1px dashed var(--border-strong);
  font-size: 0.78rem;
  font-weight: 600;
  padding: 8px 12px;
  border-radius: var(--radius-full);
  cursor: pointer;
  transition: var(--transition-fast);
}

.adjust-time-btn:hover {
  color: var(--text-primary);
  border-color: var(--accent-primary);
  background: var(--bg-card);
}

/* Quick Stats Bar */
.pomodoro-quick-stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 14px;
  width: 100%;
}

.stat-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 16px;
  text-align: center;
  box-shadow: var(--shadow-sm);
}

.stat-number {
  font-family: var(--font-heading);
  font-size: 1.6rem;
  font-weight: 800;
  color: var(--text-primary);
  display: block;
}

.stat-title {
  font-size: 0.75rem;
  color: var(--text-muted);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

/* ===================================================================
   TAB 2: FLASHCARDS
   =================================================================== */
.flashcards-container {
  display: flex;
  flex-direction: column;
  max-width: 680px;
  margin: 0 auto;
  gap: 20px;
}

.deck-toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  flex-wrap: wrap;
}

.deck-selector-wrap {
  display: flex;
  align-items: center;
  gap: 8px;
  flex: 1;
  min-width: 240px;
}

.deck-dropdown, .input-select {
  flex: 1;
  background: var(--bg-card);
  color: var(--text-primary);
  border: 1px solid var(--border-strong);
  padding: 10px 14px;
  border-radius: var(--radius-md);
  font-family: var(--font-body);
  font-size: 0.92rem;
  font-weight: 600;
  cursor: pointer;
  outline: none;
  transition: var(--transition-fast);
}

.deck-dropdown:focus, .input-select:focus {
  border-color: var(--accent-primary);
  box-shadow: 0 0 0 3px var(--accent-glow);
}

.deck-dropdown option, .input-select option {
  background: var(--bg-elevated);
  color: var(--text-primary);
}

.deck-actions {
  display: flex;
  gap: 8px;
}

/* Deck Progress */
.deck-progress-bar-wrap {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.deck-meta {
  display: flex;
  justify-content: space-between;
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--text-muted);
}

.deck-mastery-label {
  color: var(--color-success);
}

.progress-track {
  width: 100%;
  height: 8px;
  background: var(--border-subtle);
  border-radius: var(--radius-full);
  overflow: hidden;
}

.progress-fill {
  height: 100%;
  background: var(--accent-gradient);
  border-radius: var(--radius-full);
  transition: width 0.4s ease;
}

/* 3D Flashcard Flip Scene */
.flashcard-scene {
  perspective: 1200px;
  width: 100%;
  height: 340px;
  cursor: pointer;
  margin: 4px 0;
}

.flashcard {
  width: 100%;
  height: 100%;
  position: relative;
  transform-style: preserve-3d;
  transition: transform 0.6s cubic-bezier(0.2, 0.85, 0.4, 1.2);
  border-radius: var(--radius-lg);
}

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

.card-face {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
  border-radius: var(--radius-lg);
  padding: 28px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  box-shadow: var(--shadow-md);
  border: 1px solid var(--border-strong);
  user-select: none;
}

.card-front {
  background: linear-gradient(145deg, var(--bg-card), var(--bg-elevated));
}

.card-back {
  background: linear-gradient(145deg, #162035, #1e293b);
  transform: rotateY(180deg);
}

body.theme-light .card-back {
  background: linear-gradient(145deg, #f1f5f9, #ffffff);
}

.card-top-tag {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.card-badge-pill {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  padding: 4px 10px;
  border-radius: var(--radius-full);
  background: rgba(99, 102, 241, 0.15);
  color: var(--accent-primary);
}

.answer-badge {
  background: rgba(16, 185, 129, 0.15);
  color: var(--color-success);
}

.card-flip-prompt {
  font-size: 0.78rem;
  color: var(--text-muted);
}

.card-content-area {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 10px 14px;
  overflow-y: auto;
  max-height: 190px;
}

.card-prompt-text {
  font-family: var(--font-heading);
  font-size: 1.45rem;
  font-weight: 700;
  line-height: 1.35;
  color: var(--text-primary);
}

.card-answer-text {
  font-size: 1.15rem;
  line-height: 1.5;
  color: var(--text-primary);
  font-weight: 500;
}

.card-hint-text {
  margin-top: 12px;
  padding: 8px 14px;
  border-radius: var(--radius-sm);
  background: rgba(245, 158, 11, 0.1);
  color: #fbbf24;
  font-size: 0.85rem;
}

.card-bottom-actions {
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-top: 1px solid var(--border-subtle);
  padding-top: 14px;
  font-size: 0.8rem;
  color: var(--text-muted);
}

.card-hint-btn {
  background: transparent;
  border: 1px dashed rgba(245, 158, 11, 0.4);
  color: #fbbf24;
  padding: 4px 10px;
  border-radius: var(--radius-sm);
  font-size: 0.75rem;
  cursor: pointer;
}

.card-hint-btn:hover {
  background: rgba(245, 158, 11, 0.1);
}

/* Card Rating Bar */
.card-rating-bar {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
}

.rate-btn {
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 12px;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-subtle);
  background: var(--bg-card);
  cursor: pointer;
  transition: var(--transition-fast);
}

.rate-btn:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-sm);
}

.rate-emoji {
  font-size: 1.25rem;
  margin-bottom: 2px;
}

.rate-title {
  font-size: 0.82rem;
  font-weight: 700;
}

.rate-key {
  font-size: 0.7rem;
  color: var(--text-muted);
}

.rate-hard:hover {
  border-color: var(--color-danger);
  background: rgba(239, 68, 68, 0.1);
  color: var(--color-danger);
}

.rate-medium:hover {
  border-color: var(--color-warning);
  background: rgba(245, 158, 11, 0.1);
  color: var(--color-warning);
}

.rate-easy:hover {
  border-color: var(--color-success);
  background: rgba(16, 185, 129, 0.1);
  color: var(--color-success);
}

/* Navigation Controls */
.card-navigation-controls {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 14px;
}

/* Card List Expander */
.cards-list-expander {
  margin-top: 10px;
}

.cards-accordion {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  overflow: hidden;
}

.cards-accordion-summary {
  padding: 14px 18px;
  font-weight: 600;
  font-size: 0.9rem;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  list-style: none;
  user-select: none;
}

.cards-accordion-summary::-webkit-details-marker {
  display: none;
}

.chevron {
  font-size: 0.75rem;
  transition: transform var(--transition-fast);
}

.cards-accordion[open] .chevron {
  transform: rotate(180deg);
}

.deck-cards-table-container {
  padding: 14px 18px;
  border-top: 1px solid var(--border-subtle);
  max-height: 280px;
  overflow-y: auto;
}

.deck-cards-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.card-item-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 12px;
  background: var(--bg-elevated);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  gap: 12px;
}

.card-item-info {
  flex: 1;
  overflow: hidden;
}

.card-item-q {
  font-size: 0.88rem;
  font-weight: 600;
  color: var(--text-primary);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.card-item-a {
  font-size: 0.78rem;
  color: var(--text-muted);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.card-item-actions {
  display: flex;
  gap: 6px;
}

.card-item-btn {
  background: transparent;
  border: none;
  color: var(--text-muted);
  cursor: pointer;
  padding: 4px;
  border-radius: var(--radius-sm);
  transition: var(--transition-fast);
}

.card-item-btn:hover {
  color: var(--text-primary);
  background: var(--bg-card);
}

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

/* ===================================================================
   TAB 3: QUIZ MASTER
   =================================================================== */
.quiz-container {
  max-width: 680px;
  margin: 0 auto;
}

/* Setup Screen */
.quiz-setup-card {
  background: var(--bg-card);
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-lg);
  padding: 36px 30px;
  box-shadow: var(--shadow-md);
  text-align: center;
}

.quiz-hero-badge {
  display: inline-block;
  background: rgba(99, 102, 241, 0.15);
  color: var(--accent-primary);
  font-size: 0.8rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1px;
  padding: 6px 14px;
  border-radius: var(--radius-full);
  margin-bottom: 14px;
}

.quiz-hero-title {
  font-family: var(--font-heading);
  font-size: 2rem;
  font-weight: 800;
  margin-bottom: 8px;
}

.quiz-hero-desc {
  font-size: 0.95rem;
  color: var(--text-secondary);
  max-width: 480px;
  margin: 0 auto 28px;
}

.setup-form-group {
  text-align: left;
  margin-bottom: 16px;
}

.setup-form-group label {
  display: block;
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--text-secondary);
  margin-bottom: 6px;
}

.setup-form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 14px;
}

.quiz-launch-actions {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-top: 24px;
}

/* Play Screen */
.quiz-play-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 14px;
}

.quiz-progress-text {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-muted);
}

.quiz-score-pill {
  background: var(--bg-card);
  border: 1px solid var(--border-strong);
  padding: 4px 12px;
  border-radius: var(--radius-full);
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--accent-primary);
}

.quiz-timer-pill {
  background: rgba(245, 158, 11, 0.15);
  color: #f59e0b;
  border: 1px solid rgba(245, 158, 11, 0.3);
  padding: 4px 12px;
  border-radius: var(--radius-full);
  font-size: 0.85rem;
  font-weight: 700;
}

.quiz-track {
  margin-bottom: 22px;
}

.quiz-card {
  background: var(--bg-card);
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-lg);
  padding: 28px;
  box-shadow: var(--shadow-md);
}

.quiz-question-badge {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--text-muted);
  letter-spacing: 0.5px;
  margin-bottom: 10px;
}

.quiz-question-title {
  font-family: var(--font-heading);
  font-size: 1.35rem;
  font-weight: 700;
  line-height: 1.4;
  margin-bottom: 24px;
}

.quiz-options-grid {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.quiz-opt-btn {
  display: flex;
  align-items: center;
  gap: 12px;
  background: var(--bg-elevated);
  border: 1px solid var(--border-strong);
  color: var(--text-primary);
  font-family: var(--font-body);
  font-size: 0.95rem;
  font-weight: 500;
  padding: 14px 18px;
  border-radius: var(--radius-md);
  text-align: left;
  cursor: pointer;
  transition: var(--transition-fast);
}

.quiz-opt-btn:hover:not(:disabled) {
  border-color: var(--accent-primary);
  background: var(--bg-card-hover);
  transform: translateX(4px);
}

.quiz-opt-btn:disabled {
  cursor: default;
}

.quiz-opt-letter {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  border-radius: var(--radius-sm);
  background: var(--border-subtle);
  font-size: 0.82rem;
  font-weight: 700;
  color: var(--text-muted);
}

.quiz-opt-btn.correct {
  background: rgba(16, 185, 129, 0.15) !important;
  border-color: var(--color-success) !important;
  color: var(--color-success) !important;
}

.quiz-opt-btn.correct .quiz-opt-letter {
  background: var(--color-success);
  color: #fff;
}

.quiz-opt-btn.incorrect {
  background: rgba(239, 68, 68, 0.15) !important;
  border-color: var(--color-danger) !important;
  color: var(--color-danger) !important;
}

.quiz-opt-btn.incorrect .quiz-opt-letter {
  background: var(--color-danger);
  color: #fff;
}

/* Feedback Box */
.quiz-feedback-box {
  margin-top: 20px;
  padding: 18px;
  border-radius: var(--radius-md);
  background: var(--bg-elevated);
  border: 1px solid var(--border-strong);
  animation: fadeIn 0.25s ease-out;
}

.feedback-status {
  font-family: var(--font-heading);
  font-size: 1.1rem;
  font-weight: 700;
  margin-bottom: 6px;
}

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

.feedback-status.incorrect {
  color: var(--color-danger);
}

.feedback-explanation {
  font-size: 0.88rem;
  color: var(--text-secondary);
  margin-bottom: 16px;
  line-height: 1.45;
}

/* Results Screen */
.quiz-results-card {
  background: var(--bg-card);
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-lg);
  padding: 36px 30px;
  text-align: center;
  box-shadow: var(--shadow-md);
}

.results-trophy-icon {
  font-size: 3.5rem;
  margin-bottom: 10px;
  animation: bounceTrophy 1s ease;
}

@keyframes bounceTrophy {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-12px); }
}

.results-headline {
  font-family: var(--font-heading);
  font-size: 2rem;
  font-weight: 800;
  margin-bottom: 6px;
}

.results-subtext {
  font-size: 0.95rem;
  color: var(--text-secondary);
  margin-bottom: 24px;
}

.results-stats-row {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
  margin-bottom: 28px;
}

.results-stat-box {
  background: var(--bg-elevated);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 14px;
}

.results-big-num {
  font-family: var(--font-heading);
  font-size: 1.6rem;
  font-weight: 800;
  color: var(--text-primary);
  display: block;
}

.results-label {
  font-size: 0.75rem;
  color: var(--text-muted);
  text-transform: uppercase;
  font-weight: 600;
}

.results-review-section {
  text-align: left;
  margin-bottom: 28px;
  max-height: 240px;
  overflow-y: auto;
}

.results-review-title {
  font-size: 0.9rem;
  font-weight: 700;
  margin-bottom: 10px;
  color: var(--text-secondary);
}

.results-review-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.review-item {
  padding: 10px 14px;
  background: var(--bg-elevated);
  border-radius: var(--radius-sm);
  border-left: 4px solid var(--color-success);
  font-size: 0.85rem;
}

.review-item.failed {
  border-left-color: var(--color-danger);
}

.review-item-q {
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 2px;
}

.review-item-ans {
  color: var(--text-muted);
  font-size: 0.8rem;
}

.results-actions {
  display: flex;
  gap: 12px;
  justify-content: center;
  flex-wrap: wrap;
}

/* ===================================================================
   TAB 4: SETTINGS & CUSTOMIZATION
   =================================================================== */
.settings-container {
  max-width: 680px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.settings-header {
  margin-bottom: 8px;
}

.settings-header h2 {
  font-family: var(--font-heading);
  font-size: 1.6rem;
  font-weight: 800;
}

.settings-header p {
  font-size: 0.9rem;
  color: var(--text-secondary);
}

.settings-card {
  background: var(--bg-card);
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-lg);
  padding: 24px;
  box-shadow: var(--shadow-sm);
}

.settings-card-title {
  display: flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-heading);
  font-size: 1.15rem;
  font-weight: 700;
  margin-bottom: 16px;
}

.settings-card-desc {
  font-size: 0.88rem;
  color: var(--text-secondary);
  margin-bottom: 16px;
}

.settings-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 16px;
  margin-bottom: 20px;
}

@media (max-width: 520px) {
  .settings-grid {
    grid-template-columns: 1fr;
  }
}

.settings-input-group label {
  display: block;
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--text-secondary);
  margin-bottom: 6px;
}

.settings-input-group input {
  width: 100%;
  background: var(--bg-elevated);
  border: 1px solid var(--border-strong);
  color: var(--text-primary);
  font-family: var(--font-body);
  font-size: 0.95rem;
  padding: 10px 14px;
  border-radius: var(--radius-md);
  outline: none;
}

.settings-input-group input:focus {
  border-color: var(--accent-primary);
}

.settings-toggle-row {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 14px 0;
  border-top: 1px solid var(--border-subtle);
  border-bottom: 1px solid var(--border-subtle);
  margin-bottom: 20px;
}

.toggle-switch {
  position: relative;
  display: inline-block;
  width: 44px;
  height: 24px;
  flex-shrink: 0;
}

.toggle-switch input {
  opacity: 0;
  width: 0;
  height: 0;
}

.toggle-slider {
  position: absolute;
  cursor: pointer;
  top: 0; left: 0; right: 0; bottom: 0;
  background-color: var(--border-strong);
  transition: 0.3s;
  border-radius: 24px;
}

.toggle-slider:before {
  position: absolute;
  content: "";
  height: 18px;
  width: 18px;
  left: 3px;
  bottom: 3px;
  background-color: white;
  transition: 0.3s;
  border-radius: 50%;
}

.toggle-switch input:checked + .toggle-slider {
  background-color: var(--accent-primary);
}

.toggle-switch input:checked + .toggle-slider:before {
  transform: translateX(20px);
}

.toggle-title {
  font-size: 0.88rem;
  font-weight: 600;
  display: block;
}

.toggle-desc {
  font-size: 0.78rem;
  color: var(--text-muted);
}

.settings-actions {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
}

.data-management-buttons {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
}

/* ===================================================================
   MODALS
   =================================================================== */
.modal-backdrop {
  position: fixed;
  top: 0; left: 0; right: 0; bottom: 0;
  background: rgba(0, 0, 0, 0.7);
  backdrop-filter: blur(6px);
  display: none;
  align-items: center;
  justify-content: center;
  padding: 20px;
  z-index: 200;
  animation: fadeIn 0.2s ease-out;
}

.modal-backdrop.show {
  display: flex;
}

.modal-window {
  background: var(--bg-secondary);
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-lg);
  width: 100%;
  max-width: 520px;
  box-shadow: var(--shadow-lg);
  overflow: hidden;
  animation: popIn 0.25s cubic-bezier(0.16, 1, 0.3, 1);
}

.modal-window.modal-wide {
  max-width: 640px;
}

@keyframes popIn {
  from { opacity: 0; transform: scale(0.95) translateY(10px); }
  to { opacity: 1; transform: scale(1) translateY(0); }
}

.modal-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 18px 24px;
  border-bottom: 1px solid var(--border-subtle);
}

.modal-header h3 {
  font-family: var(--font-heading);
  font-size: 1.2rem;
  font-weight: 700;
}

.modal-close-btn {
  background: transparent;
  border: none;
  font-size: 1.6rem;
  line-height: 1;
  color: var(--text-muted);
  cursor: pointer;
}

.modal-close-btn:hover {
  color: var(--text-primary);
}

.modal-body {
  padding: 20px 24px;
  max-height: 70vh;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.form-group label {
  display: block;
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--text-secondary);
  margin-bottom: 6px;
}

.form-group input[type="text"],
.form-group textarea {
  width: 100%;
  background: var(--bg-elevated);
  border: 1px solid var(--border-strong);
  color: var(--text-primary);
  font-family: var(--font-body);
  font-size: 0.92rem;
  padding: 10px 14px;
  border-radius: var(--radius-md);
  outline: none;
  transition: var(--transition-fast);
}

.form-group input[type="text"]:focus,
.form-group textarea:focus {
  border-color: var(--accent-primary);
  box-shadow: 0 0 0 3px var(--accent-glow);
}

.option-input-row {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 8px;
}

.option-input-row input[type="radio"] {
  accent-color: var(--color-success);
  width: 18px;
  height: 18px;
  cursor: pointer;
}

.modal-footer {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 10px;
  padding: 16px 24px;
  border-top: 1px solid var(--border-subtle);
  background: var(--bg-card);
}

/* Decks Management Modal Specifics */
.new-deck-box {
  background: var(--bg-elevated);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 16px;
}

.new-deck-box h4 {
  font-size: 0.85rem;
  font-weight: 700;
  margin-bottom: 10px;
  color: var(--text-secondary);
}

.new-deck-form {
  display: flex;
  gap: 8px;
}

.new-deck-form input {
  background: var(--bg-card);
  border: 1px solid var(--border-strong);
  color: var(--text-primary);
  padding: 8px 12px;
  border-radius: var(--radius-sm);
  font-family: var(--font-body);
}

.existing-decks-list-wrap h4 {
  font-size: 0.85rem;
  font-weight: 700;
  margin-bottom: 10px;
  color: var(--text-secondary);
}

.decks-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.deck-manage-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 14px;
  background: var(--bg-elevated);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
}

.deck-manage-title {
  display: flex;
  align-items: center;
  gap: 8px;
  font-weight: 600;
  font-size: 0.92rem;
}

.deck-card-pill {
  font-size: 0.72rem;
  background: var(--border-subtle);
  padding: 2px 8px;
  border-radius: var(--radius-full);
  color: var(--text-muted);
}

/* ===================================================================
   TOAST NOTIFICATIONS
   =================================================================== */
.toast-container {
  position: fixed;
  bottom: 24px;
  right: 24px;
  display: flex;
  flex-direction: column;
  gap: 8px;
  z-index: 300;
  pointer-events: none;
}

.toast {
  background: var(--bg-elevated);
  color: var(--text-primary);
  border: 1px solid var(--border-strong);
  padding: 12px 18px;
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg);
  font-size: 0.88rem;
  font-weight: 600;
  display: flex;
  align-items: center;
  gap: 10px;
  animation: slideInRight 0.3s cubic-bezier(0.16, 1, 0.3, 1);
  pointer-events: auto;
}

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

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

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

@keyframes slideInRight {
  from { opacity: 0; transform: translateX(40px); }
  to { opacity: 1; transform: translateX(0); }
}

/* Confetti Canvas */
#confettiCanvas {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  pointer-events: none;
  z-index: 999;
}

/* Responsive adjustments */
@media (max-width: 640px) {
  .app-layout {
    padding: 0 12px 30px;
  }

  .clock-display-wrap {
    width: 270px;
    height: 270px;
  }

  .time-countdown {
    font-size: 3.4rem;
  }

  .flashcard-scene {
    height: 310px;
  }

  .card-prompt-text {
    font-size: 1.25rem;
  }

  .card-answer-text {
    font-size: 1.02rem;
  }

  .setup-form-row {
    grid-template-columns: 1fr;
  }
}