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

body {
  font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 20px;
  background: linear-gradient(135deg, #0f0f1e 0%, #1a1a2e 100%);
}

/* ===========================
   LOADING & UTILITIES
   =========================== */

.loading-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.8);
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  z-index: 9999;
}

.loading-text {
  color: white;
  font-size: 1.5em;
  font-weight: 600;
  animation: fadeInOut 1.5s ease-in-out infinite;
}

@keyframes fadeInOut {
  0%,
  100% {
    opacity: 0.4;
  }
  50% {
    opacity: 1;
  }
}

.loading-spinner {
  border: 4px solid rgba(255, 255, 255, 0.3);
  border-top: 4px solid #fff;
  border-radius: 50%;
  width: 50px;
  height: 50px;
  animation: spin 1s linear infinite;
  margin-bottom: 20px;
}

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

.loading-overlay p {
  color: white;
  font-size: 18px;
}

.hidden {
  display: none !important;
}

/* Confetti Canvas */
.confetti-canvas-fullscreen {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  z-index: 9998;
}

/* ===========================
   HOMEPAGE STYLES
   =========================== */

.homepage {
  background: linear-gradient(135deg, #1a1a2e 0%, #16213e 100%);
  max-width: 1000px;
  width: 100%;
  text-align: center;
  padding: 40px 20px;
  border-radius: 20px;
}

.header h1 {
  color: white;
  font-size: 2.2em;
  margin-bottom: 10px;
  text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.3);
}

.subtitle {
  color: rgba(255, 255, 255, 0.9);
  font-size: 1.3em;
  margin-bottom: 40px;
}

/* Unit Cards */
.unit-cards {
  display: flex;
  flex-direction: column;
  gap: 20px;
  margin-bottom: 40px;
}

.unit-card {
  background: linear-gradient(
    135deg,
    rgba(255, 255, 255, 0.08) 0%,
    rgba(255, 255, 255, 0.05) 100%
  );
  backdrop-filter: blur(10px);
  border: 1px solid rgba(255, 255, 255, 0.1);
  padding: 25px;
  border-radius: 16px;
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.3);
  transition: all 0.3s ease;
}

.unit-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 12px 40px rgba(0, 0, 0, 0.4);
  border-color: rgba(255, 255, 255, 0.2);
  background: linear-gradient(
    135deg,
    rgba(255, 255, 255, 0.12) 0%,
    rgba(255, 255, 255, 0.08) 100%
  );
}

.unit-card-title {
  color: #e0e0e0;
  font-size: 1.4em;
  margin-bottom: 15px;
  font-weight: 600;
  text-shadow: 0 2px 4px rgba(0, 0, 0, 0.3);
}

.unit-buttons {
  display: flex;
  gap: 12px;
  justify-content: center;
}

.study-btn,
.quiz-btn {
  flex: 1;
  padding: 14px 24px;
  font-size: 1.2em;
  font-weight: 600;
  border: none;
  border-radius: 10px;
  cursor: pointer;
  transition: all 0.3s ease;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
}

.study-btn {
  background: linear-gradient(135deg, #11998e 0%, #38ef7d 100%);
  color: white;
}

.study-btn:hover {
  background: linear-gradient(135deg, #0d7a6e 0%, #2ed968 100%);
  transform: translateY(-2px);
  box-shadow: 0 6px 16px rgba(17, 153, 142, 0.4);
}

.quiz-btn {
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: white;
}

.quiz-btn:hover {
  background: linear-gradient(135deg, #5568d3 0%, #6a4291 100%);
  transform: translateY(-2px);
  box-shadow: 0 6px 16px rgba(102, 126, 234, 0.4);
}

/* BIG 100 Section */
.big100-section {
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  padding: 40px;
  border-radius: 16px;
  box-shadow: 0 8px 16px rgba(0, 0, 0, 0.2);
}

.big100-content h2 {
  color: white;
  font-size: 2em;
  margin-bottom: 10px;
  text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.3);
}

.big100-content p {
  color: rgba(255, 255, 255, 0.9);
  font-size: 1.1em;
  margin-bottom: 20px;
}

.big100-btn {
  background: white;
  color: #667eea;
  padding: 15px 40px;
  font-size: 1.2em;
  font-weight: 600;
  border: none;
  border-radius: 10px;
  cursor: pointer;
  transition: all 0.3s ease;
  box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
}

.big100-btn:hover {
  background: #f8f9ff;
  transform: translateY(-3px);
  box-shadow: 0 6px 12px rgba(0, 0, 0, 0.3);
}

/* ===========================
   FLASHCARD STYLES
   =========================== */

.flashcard-view {
  background: linear-gradient(135deg, #11998e 0%, #38ef7d 100%);
  max-width: 1000px;
  width: 100%;
  min-height: 100vh;
  padding: 20px;
}

.back-btn {
  background: rgba(255, 255, 255, 0.2);
  color: white;
  border: 2px solid white;
  padding: 10px 20px;
  font-size: 1em;
  border-radius: 8px;
  cursor: pointer;
  transition: all 0.3s ease;
  margin-bottom: 20px;
}

.back-btn:hover {
  background: white;
  color: #11998e;
}

.flashcard-header {
  text-align: center;
  margin-bottom: 40px;
}

.flashcard-header h2 {
  color: white;
  font-size: 1.8em;
  margin-bottom: 8px;
  text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.3);
  font-weight: 500;
}

.unit-subtitle {
  color: rgba(255, 255, 255, 0.85);
  font-size: 1.1em;
  margin: 0;
  text-shadow: 1px 1px 2px rgba(0, 0, 0, 0.3);
}

.instruction {
  color: rgba(255, 255, 255, 0.6);
  font-size: 0.9em;
}

/* Flashcard Container */
.flashcard-container {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 30px;
  min-height: 600px;
  perspective: 1000px;
}

/* Navigation Arrows */
.nav-arrow {
  width: 60px;
  height: 60px;
  border-radius: 50%;
  background: white;
  border: none;
  color: #11998e;
  font-size: 28px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.3s ease;
  box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
  flex-shrink: 0;
}

.nav-arrow:hover {
  transform: scale(1.1);
  background: #f0f0f0;
  box-shadow: 0 6px 12px rgba(0, 0, 0, 0.3);
}

.nav-arrow:active {
  transform: scale(0.95);
}

.nav-arrow:disabled {
  opacity: 0.3;
  cursor: not-allowed;
}

.nav-arrow:disabled:hover {
  transform: scale(1);
  background: white;
}

.card-stack {
  position: relative;
  width: 100%;
  max-width: 500px;
  height: 600px;
}

.card-stack-item {
  position: absolute;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.3);
  border-radius: 16px;
  pointer-events: none;
}

.stack-2 {
  transform: translateY(-8px) translateX(-4px) rotate(-1deg);
  z-index: 1;
}

.stack-3 {
  transform: translateY(-16px) translateX(-8px) rotate(-2deg);
  z-index: 0;
}

.flashcard {
  position: relative;
  width: 100%;
  height: 100%;
  cursor: pointer;
  z-index: 2;
}

.flashcard-inner {
  position: relative;
  width: 100%;
  height: 100%;
  transition: transform 0.6s;
  transform-style: preserve-3d;
}

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

.flashcard-front,
.flashcard-back {
  position: absolute;
  width: 100%;
  height: 100%;
  backface-visibility: hidden;
  border-radius: 16px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  padding: 40px;
  box-shadow: 0 8px 16px rgba(0, 0, 0, 0.3);
}

.flashcard-front {
  background: #000;
  color: white;
}

.flashcard-back {
  background: white;
  color: #000;
  transform: rotateY(180deg);
}

.card-content {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  font-size: 1.55em;
  line-height: 1.6;
  overflow-y: auto;
  width: 100%;
}

.show-answer-text {
  color: rgba(128, 128, 128, 0.6);
  font-size: 0.9em;
  text-align: center;
  cursor: pointer;
  margin-top: 20px;
  user-select: none;
  transition: color 0.3s ease;
}

.show-answer-text:hover {
  color: rgba(128, 128, 128, 0.8);
}

/* Progress Section (shared by flashcards and quiz) */
.progress-section {
  max-width: 800px;
  margin: 30px auto 0;
  padding: 0 20px;
}

.progress-bar-container {
  display: flex;
  align-items: center;
  gap: 20px;
  background: rgba(255, 255, 255, 0.3);
  padding: 15px 20px;
  border-radius: 12px;
}

.progress-bar {
  flex: 1;
  height: 12px;
  background: rgba(255, 255, 255, 0.3);
  border-radius: 10px;
  overflow: hidden;
}

.progress-bar-fill {
  height: 100%;
  background: linear-gradient(90deg, #2196f3 0%, #1976d2 100%);
  border-radius: 10px;
  transition: width 0.4s ease;
}

/* Quiz progress bar - RED */
.quiz-progress-fill {
  background: linear-gradient(90deg, #dc3545 0%, #c82333 100%) !important;
}

.progress-counter {
  color: white;
  font-size: 1em;
  font-weight: 600;
  margin: 0;
  white-space: nowrap;
  min-width: 80px;
  text-align: right;
  text-shadow: 1px 1px 2px rgba(0, 0, 0, 0.3);
}

.keyboard-tip {
  color: rgba(255, 255, 255, 0.6);
  font-size: 0.85em;
  text-align: center;
  margin-top: 10px;
  text-shadow: 1px 1px 2px rgba(0, 0, 0, 0.3);
}

/* Error Message */
.error-message {
  text-align: center;
  color: white;
  font-size: 1.2em;
  background: rgba(255, 0, 0, 0.3);
  padding: 20px;
  border-radius: 12px;
  margin-top: 20px;
}

/* Completion Screen */
.completion-screen {
  position: relative;
  text-align: center;
  background: white;
  padding: 60px 40px;
  border-radius: 16px;
  box-shadow: 0 8px 16px rgba(0, 0, 0, 0.3);
  margin: 40px auto;
  max-width: 500px;
}

.completion-content {
  position: relative;
  z-index: 2;
}

.completion-icon {
  font-size: 5em;
  margin-bottom: 20px;
}

.checkmark-icon {
  animation: checkPop 0.5s ease;
}

@keyframes checkPop {
  0% {
    transform: scale(0);
    opacity: 0;
  }
  50% {
    transform: scale(1.2);
    opacity: 1;
  }
  100% {
    transform: scale(1);
    opacity: 1;
  }
}

.sparkles-container {
  position: relative;
  height: 40px;
  margin-bottom: 20px;
}

.sparkle {
  position: absolute;
  font-size: 1.5em;
  animation: sparkleAnimation 1.5s ease forwards;
  opacity: 0;
}

.sparkle:nth-child(1) {
  left: 20%;
  animation-delay: 0s;
}

.sparkle:nth-child(2) {
  left: 35%;
  animation-delay: 0.1s;
}

.sparkle:nth-child(3) {
  left: 50%;
  animation-delay: 0.2s;
}

.sparkle:nth-child(4) {
  left: 65%;
  animation-delay: 0.1s;
}

.sparkle:nth-child(5) {
  left: 80%;
  animation-delay: 0s;
}

@keyframes sparkleAnimation {
  0% {
    opacity: 0;
    transform: scale(0) translateY(20px);
  }
  50% {
    opacity: 1;
    transform: scale(1) translateY(0);
  }
  100% {
    opacity: 0;
    transform: scale(0.5) translateY(-10px);
  }
}

@keyframes bounce {
  0%,
  100% {
    transform: translateY(0);
  }
  50% {
    transform: translateY(-20px);
  }
}

.completion-screen h2 {
  color: #11998e;
  font-size: 2.2em;
  margin-bottom: 15px;
  font-weight: 600;
}

.completion-message {
  color: #666;
  font-size: 1.2em;
  margin-bottom: 35px;
  line-height: 1.5;
}

.completion-buttons {
  display: flex;
  gap: 15px;
  justify-content: center;
  flex-wrap: wrap;
}

.return-btn,
.take-quiz-btn {
  background: #11998e;
  color: white;
  border: none;
  padding: 16px 40px;
  font-size: 1.1em;
  font-weight: 600;
  border-radius: 10px;
  cursor: pointer;
  transition: all 0.3s ease;
  box-shadow: 0 4px 8px rgba(17, 153, 142, 0.3);
}

.take-quiz-btn {
  background: #667eea;
}

.return-btn:hover {
  background: #0e7c6e;
  transform: translateY(-3px);
  box-shadow: 0 6px 12px rgba(17, 153, 142, 0.4);
}

.take-quiz-btn:hover {
  background: #5568d3;
  transform: translateY(-3px);
  box-shadow: 0 6px 12px rgba(102, 126, 234, 0.4);
}

/* ===========================
   QUIZ STYLES
   =========================== */

.quiz-view {
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  max-width: 1000px;
  width: 100%;
  min-height: 100vh;
  padding: 20px;
}

.quiz-view .back-btn:hover {
  color: #667eea;
}

.quiz-header {
  text-align: center;
  margin-bottom: 30px;
}

.quiz-header h2 {
  color: white;
  font-size: 1.5em;
  margin-bottom: 15px;
  text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.3);
  font-weight: 500;
}

.quiz-progress-header {
  max-width: 600px;
  margin: 0 auto;
}

.quiz-progress-header .progress-bar-container {
  background: rgba(255, 255, 255, 0.2);
  padding: 10px 15px;
  border-radius: 12px;
  display: flex;
  align-items: center;
  gap: 15px;
}

.quiz-counter {
  color: rgba(255, 255, 255, 0.9);
  font-size: 1em;
}

/* Quiz Question Container */
.quiz-question-container {
  background: white;
  padding: 40px;
  border-radius: 16px;
  box-shadow: 0 8px 16px rgba(0, 0, 0, 0.2);
  margin-bottom: 20px;
}

.question-text {
  font-size: 1.3em;
  color: #333;
  margin-bottom: 30px;
  line-height: 1.6;
  font-weight: 500;
}

/* Answer Options */
.answer-options {
  display: flex;
  flex-direction: column;
  gap: 15px;
  margin-bottom: 25px;
}

.answer-option {
  background: #f8f9fa;
  border: 3px solid #e0e0e0;
  padding: 20px;
  border-radius: 12px;
  cursor: pointer;
  transition: all 0.3s ease;
  text-align: left;
}

.answer-option:hover:not(.disabled) {
  background: #e9ecef;
  border-color: #667eea;
  transform: translateX(5px);
}

.answer-option.selected {
  border-color: #667eea;
  background: #e8eaf6;
}

.answer-option.correct {
  background: #d4edda !important;
  border-color: #28a745 !important;
}

.answer-option.wrong {
  background: #f8d7da !important;
  border-color: #dc3545 !important;
}

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

.answer-letter {
  font-weight: 700;
  color: #667eea;
  margin-right: 10px;
  font-size: 1.1em;
}

.answer-option.correct .answer-letter {
  color: #28a745;
}

.answer-option.wrong .answer-letter {
  color: #dc3545;
}

.answer-text {
  display: inline;
  font-size: 1.05em;
  color: #333;
}

.answer-explanation {
  margin-top: 15px;
  padding-top: 15px;
  border-top: 2px solid rgba(0, 0, 0, 0.1);
  font-size: 0.95em;
  line-height: 1.5;
  color: #155724;
}

/* Hint Section */
.hint-section {
  margin-bottom: 25px;
}

.hint-toggle {
  background: transparent;
  border: none;
  color: #667eea;
  font-size: 1em;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 10px 0;
  transition: all 0.3s ease;
}

.hint-toggle:hover {
  color: #5568d3;
}

.hint-icon {
  font-size: 1.2em;
}

.hint-arrow {
  transition: transform 0.3s ease;
  margin-left: auto;
}

.hint-toggle.expanded .hint-arrow {
  transform: rotate(180deg);
}

.hint-content {
  background: #fff9e6;
  border-left: 4px solid #ffc107;
  padding: 15px;
  margin-top: 10px;
  border-radius: 8px;
  color: #856404;
  line-height: 1.5;
}

/* Skipped Questions Button */
.skipped-questions-btn-container {
  text-align: center;
  margin: 20px 0 15px 0;
}

.skipped-questions-btn {
  background: linear-gradient(135deg, #f39c12 0%, #e67e22 100%);
  color: white;
  border: none;
  padding: 12px 24px;
  font-size: 1em;
  font-weight: 600;
  border-radius: 8px;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  box-shadow: 0 4px 12px rgba(243, 156, 18, 0.3);
  transition: all 0.3s ease;
}

.skipped-questions-btn:hover {
  background: linear-gradient(135deg, #e67e22 0%, #d35400 100%);
  transform: translateY(-2px);
  box-shadow: 0 6px 16px rgba(243, 156, 18, 0.4);
}

.skipped-icon {
  font-size: 1.2em;
}

/* Modal Overlay */
.modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.8);
  display: flex;
  justify-content: center;
  align-items: center;
  z-index: 10000;
}

/* Skipped Questions Modal */
.skipped-modal {
  background: white;
  border-radius: 16px;
  width: 90%;
  max-width: 600px;
  max-height: 80vh;
  display: flex;
  flex-direction: column;
  box-shadow: 0 10px 40px rgba(0, 0, 0, 0.3);
}

.skipped-modal-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 20px 25px;
  border-bottom: 2px solid #f0f0f0;
}

.skipped-modal-header h3 {
  margin: 0;
  color: #333;
  font-size: 1.3em;
}

.modal-close-btn {
  background: none;
  border: none;
  font-size: 2em;
  color: #999;
  cursor: pointer;
  line-height: 1;
  padding: 0;
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  transition: all 0.3s ease;
}

.modal-close-btn:hover {
  background: #f0f0f0;
  color: #333;
}

.skipped-modal-content {
  padding: 20px 25px;
  overflow-y: auto;
  flex: 1;
}

.skipped-question-item {
  padding: 20px;
  margin-bottom: 15px;
  border: 2px solid #f0f0f0;
  border-radius: 12px;
  transition: all 0.3s ease;
}

.skipped-question-item:hover {
  border-color: #f39c12;
  background: rgba(243, 156, 18, 0.05);
}

.skipped-question-number {
  font-weight: 700;
  color: #f39c12;
  margin-bottom: 8px;
  font-size: 1.1em;
}

.skipped-question-text {
  color: #666;
  margin-bottom: 15px;
  line-height: 1.5;
}

.go-to-question-btn {
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: white;
  border: none;
  padding: 10px 20px;
  font-size: 0.95em;
  font-weight: 600;
  border-radius: 8px;
  cursor: pointer;
  transition: all 0.3s ease;
  width: 100%;
}

.go-to-question-btn:hover {
  background: linear-gradient(135deg, #5568d3 0%, #6a4291 100%);
  transform: translateY(-2px);
}

/* Warning Modal */
.warning-modal {
  background: white;
  border-radius: 16px;
  padding: 40px;
  width: 90%;
  max-width: 500px;
  text-align: center;
  box-shadow: 0 10px 40px rgba(0, 0, 0, 0.3);
}

.warning-icon {
  font-size: 4em;
  margin-bottom: 20px;
}

.warning-modal h3 {
  color: #333;
  font-size: 1.5em;
  margin-bottom: 15px;
  font-weight: 700;
}

.warning-modal p {
  color: #666;
  font-size: 1.1em;
  margin-bottom: 15px;
  line-height: 1.5;
}

.warning-note {
  color: #f39c12;
  font-size: 0.95em !important;
  font-style: italic;
  margin-bottom: 25px !important;
}

.warning-buttons {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.warning-btn {
  padding: 14px 28px;
  font-size: 1.05em;
  font-weight: 600;
  border: none;
  border-radius: 8px;
  cursor: pointer;
  transition: all 0.3s ease;
  width: 100%;
}

.warning-btn.review-btn {
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: white;
}

.warning-btn.review-btn:hover {
  background: linear-gradient(135deg, #5568d3 0%, #6a4291 100%);
  transform: translateY(-2px);
}

.warning-btn.finish-btn {
  background: #6c757d;
  color: white;
}

.warning-btn.finish-btn:hover {
  background: #5a6268;
  transform: translateY(-2px);
}

/* Quiz Navigation */
.quiz-navigation {
  display: flex;
  gap: 10px;
  justify-content: space-between;
  align-items: center;
  margin-top: 25px;
}

.quiz-nav-btn {
  padding: 12px 24px;
  font-size: 1em;
  font-weight: 600;
  border: none;
  border-radius: 8px;
  cursor: pointer;
  transition: all 0.3s ease;
}

.quiz-nav-btn:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

.quiz-nav-btn:not(:disabled):hover {
  transform: translateY(-2px);
}

#prevQuestionBtn {
  background: #6c757d;
  color: white;
}

#prevQuestionBtn:hover:not(:disabled) {
  background: #5a6268;
}

.skip-btn {
  background: #ffc107;
  color: #333;
}

.skip-btn:hover:not(:disabled) {
  background: #e0a800;
}

.next-btn,
.finish-btn {
  background: #667eea;
  color: white;
}

.next-btn:hover:not(:disabled),
.finish-btn:hover:not(:disabled) {
  background: #5568d3;
}

/* Quiz Finish Screen */
.quiz-finish-screen {
  background: white;
  padding: 60px 40px;
  border-radius: 16px;
  box-shadow: 0 8px 16px rgba(0, 0, 0, 0.2);
  text-align: center;
}

.finish-icon-container {
  position: relative;
  display: inline-block;
  margin-bottom: 20px;
}

.finish-icon {
  font-size: 5em;
  display: inline-block;
}

.finish-icon.trophy-pulse {
  animation: trophyPulse 0.6s ease;
}

@keyframes trophyPulse {
  0% {
    transform: scale(0);
    filter: drop-shadow(0 0 0 rgba(255, 215, 0, 0));
  }
  50% {
    transform: scale(1.3);
    filter: drop-shadow(0 0 20px rgba(255, 215, 0, 0.8));
  }
  100% {
    transform: scale(1);
    filter: drop-shadow(0 0 10px rgba(255, 215, 0, 0.4));
  }
}

.finish-icon.star-glow {
  animation: starGlow 0.6s ease;
}

@keyframes starGlow {
  0%,
  100% {
    transform: scale(1);
    filter: brightness(1);
  }
  50% {
    transform: scale(1.1);
    filter: brightness(1.3);
  }
}

.finish-icon.plant-bounce {
  animation: plantBounce 0.6s ease;
}

@keyframes plantBounce {
  0%,
  100% {
    transform: translateY(0);
  }
  50% {
    transform: translateY(-15px);
  }
}

.finish-title {
  color: #667eea;
  font-size: 2.5em;
  margin-bottom: 20px;
  font-weight: 700;
}

.finish-message {
  color: #666;
  font-size: 1.2em;
  margin-bottom: 30px;
  line-height: 1.5;
}

.score-cards {
  display: flex;
  gap: 20px;
  justify-content: center;
  margin-bottom: 40px;
  flex-wrap: wrap;
}

.score-card {
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: white;
  padding: 30px 40px;
  border-radius: 12px;
  min-width: 200px;
  box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
}

.score-card h3 {
  font-size: 1.2em;
  margin-bottom: 15px;
  opacity: 0.9;
}

.score-value {
  font-size: 2.5em;
  font-weight: 700;
}

/* Score Breakdown */
.score-breakdown {
  background: #f8f9fa;
  border-radius: 12px;
  padding: 25px;
  margin-bottom: 30px;
  text-align: left;
  max-width: 400px;
  margin-left: auto;
  margin-right: auto;
}

.score-breakdown h4 {
  color: #333;
  font-size: 1.1em;
  margin-bottom: 15px;
  font-weight: 700;
}

.breakdown-item {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px 0;
  border-bottom: 1px solid #e0e0e0;
}

.breakdown-item:last-child {
  border-bottom: none;
}

.breakdown-icon {
  font-size: 1.3em;
  min-width: 25px;
}

.breakdown-text {
  color: #666;
  font-size: 1em;
  font-weight: 500;
}

.correct-item .breakdown-icon {
  color: #28a745;
}

.correct-item .breakdown-text {
  color: #28a745;
}

.wrong-item .breakdown-icon {
  color: #dc3545;
}

.wrong-item .breakdown-text {
  color: #dc3545;
}

.skipped-item .breakdown-icon {
  color: #f39c12;
}

.skipped-item .breakdown-text {
  color: #f39c12;
}

.finish-buttons,
.review-buttons {
  display: flex;
  gap: 15px;
  justify-content: center;
  flex-wrap: wrap;
}

.finish-action-btn {
  background: #667eea;
  color: white;
  border: none;
  padding: 15px 30px;
  font-size: 1.1em;
  font-weight: 600;
  border-radius: 10px;
  cursor: pointer;
  transition: all 0.3s ease;
}

.finish-action-btn:hover {
  background: #5568d3;
  transform: translateY(-2px);
  box-shadow: 0 4px 8px rgba(102, 126, 234, 0.3);
}

/* Quiz Review Screen */
.quiz-review-screen {
  background: white;
  padding: 40px;
  border-radius: 16px;
  box-shadow: 0 8px 16px rgba(0, 0, 0, 0.2);
}

.review-title {
  color: #667eea;
  font-size: 2em;
  margin-bottom: 30px;
  text-align: center;
}

.review-questions-container {
  display: flex;
  flex-direction: column;
  gap: 25px;
  margin-bottom: 30px;
}

.review-question-card {
  background: #f8f9fa;
  padding: 25px;
  border-radius: 12px;
  border-left: 5px solid #28a745;
}

.review-question-number {
  color: #667eea;
  font-weight: 700;
  font-size: 1.1em;
  margin-bottom: 10px;
}

.review-question-text {
  color: #333;
  font-size: 1.1em;
  margin-bottom: 15px;
  font-weight: 500;
}

.review-correct-answer {
  background: #d4edda;
  padding: 15px;
  border-radius: 8px;
  margin-bottom: 10px;
}

.review-answer-label {
  color: #28a745;
  font-weight: 700;
  margin-bottom: 5px;
}

.review-explanation {
  color: #155724;
  line-height: 1.6;
  font-size: 0.95em;
}

.review-buttons {
  margin-top: 30px;
}

/* ============================================
   FOOTER STYLES - LEFT ALIGNED SINGLE LINE
   ============================================ */

.site-footer {
  width: 100%;
  margin-top: 80px;
  padding: 0;
  background: transparent;
  position: relative;
  clear: both;
  display: block;
}

.footer-separator {
  width: 100%;
  height: 2px;
  background: linear-gradient(
    90deg,
    transparent 0%,
    rgba(17, 153, 142, 0.3) 20%,
    rgba(56, 239, 125, 0.6) 50%,
    rgba(17, 153, 142, 0.3) 80%,
    transparent 100%
  );
  margin: 0;
}

.footer-content {
  display: flex;
  justify-content: center;
  max-width: 1200px;
  margin: 0 auto;
  padding: 30px 40px;
  width: 100%;
  box-sizing: border-box;
}

.footer-credit {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 1em;
  font-weight: 500;
  color: rgba(255, 255, 255, 0.9);
  margin: 0;
  letter-spacing: 0.3px;
}

.footer-logo-link {
  display: inline-flex;
  align-items: center;
  text-decoration: none;
  transition: all 0.3s ease;
}

.footer-logo {
  width: 40px;
  height: auto;
  display: block;
  transition: all 0.3s ease;
  filter: drop-shadow(0 4px 12px rgba(56, 239, 125, 0.3));
  vertical-align: middle;
}

.footer-logo-link:hover .footer-logo {
  transform: scale(1.1);
  filter: drop-shadow(0 6px 20px rgba(56, 239, 125, 0.6));
}

/* ===========================
   MOBILE RESPONSIVE
   =========================== */

@media (max-width: 768px) {
  .header h1 {
    font-size: 1.8em;
  }

  .subtitle {
    font-size: 1em;
  }

  .unit-card-title {
    font-size: 1.1em;
  }

  .study-btn,
  .quiz-btn {
    font-size: 0.95em;
  }

  .unit-buttons {
    flex-direction: column;
  }

  .big100-content h2 {
    font-size: 1.5em;
  }

  .flashcard-header h2,
  .quiz-header h2 {
    font-size: 1.1em;
  }

  .instruction {
    display: none;
  }

  .nav-arrow {
    display: none;
  }

  .flashcard-container {
    gap: 0;
    min-height: 500px;
  }

  .card-stack {
    max-width: 100%;
    height: 500px;
  }

  .card-stack-item {
    display: none;
  }

  .card-content {
    font-size: 1.1em;
    padding: 10px;
  }

  .flashcard-front,
  .flashcard-back {
    padding: 30px 20px;
  }

  .quiz-question-container {
    padding: 25px;
  }

  .question-text {
    font-size: 1.1em;
  }

  .quiz-navigation {
    flex-wrap: nowrap;
    gap: 8px;
  }

  .quiz-nav-btn {
    flex: 1;
    padding: 12px 8px;
    font-size: 0.95em;
    min-width: 0;
  }

  .score-cards {
    flex-direction: column;
  }

  .finish-title {
    font-size: 1.8em;
  }

  .completion-screen h2,
  .review-title {
    font-size: 1.5em;
  }

  .finish-buttons,
  .review-buttons {
    flex-direction: column;
  }

  .finish-action-btn {
    width: 100%;
  }
  .site-footer {
    margin-top: 60px;
  }

  .footer-content {
    padding: 25px 20px;
  }

  .footer-credit {
    font-size: 0.9em;
    flex-wrap: wrap;
    gap: 6px;
  }

  .footer-logo {
    width: 30px;
  }
}

@media (max-width: 480px) {
  .header h1 {
    font-size: 1.5em;
  }

  .card-stack {
    height: 450px;
  }

  .card-content {
    font-size: 1em;
  }

  .quiz-question-container {
    padding: 20px;
  }
  .footer-content {
    padding: 20px 15px;
  }

  .footer-credit {
    font-size: 0.85em;
    gap: 5px;
  }

  .footer-logo {
    width: 28px;
  }
}

/* ============================================
   KNOWLEDGE CHECK & FEEDBACK SYSTEM STYLES
   ============================================ */

/* Knowledge Check Button */
.knowledge-check-btn {
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: white;
  border: none;
  padding: 12px 30px;
  font-size: 1em;
  font-weight: 600;
  border-radius: 10px;
  cursor: pointer;
  transition: all 0.3s ease;
  margin-top: 15px;
  box-shadow: 0 4px 12px rgba(102, 126, 234, 0.3);
}

.knowledge-check-btn:hover {
  background: linear-gradient(135deg, #5568d3 0%, #6a4291 100%);
  transform: translateY(-2px);
  box-shadow: 0 6px 16px rgba(102, 126, 234, 0.4);
}

/* Modal Overlay */
.modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.8);
  display: flex;
  justify-content: center;
  align-items: center;
  z-index: 10000;
  animation: fadeIn 0.3s ease;
}

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

/* Modal Content */
.modal-content {
  background: white;
  border-radius: 16px;
  padding: 40px;
  max-width: 700px;
  width: 90%;
  max-height: 90vh;
  overflow-y: auto;
  position: relative;
  box-shadow: 0 10px 40px rgba(0, 0, 0, 0.3);
  animation: slideUp 0.3s ease;
}

@keyframes slideUp {
  from {
    transform: translateY(50px);
    opacity: 0;
  }
  to {
    transform: translateY(0);
    opacity: 1;
  }
}

.final-feedback-modal {
  max-width: 800px;
}

/* Modal Close Button */
.modal-close {
  position: absolute;
  top: 15px;
  right: 15px;
  background: none;
  border: none;
  font-size: 2em;
  color: #999;
  cursor: pointer;
  transition: color 0.3s ease;
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.modal-close:hover {
  color: #333;
}

/* ===== KNOWLEDGE CHECK STYLES ===== */

.kc-screen h2 {
  color: #667eea;
  font-size: 2em;
  margin-bottom: 15px;
  text-align: center;
}

.kc-screen p {
  color: #666;
  font-size: 1.1em;
  margin-bottom: 20px;
  text-align: center;
  line-height: 1.6;
}

.kc-input-group {
  margin: 25px 0;
}

.kc-input-group label {
  display: block;
  color: #333;
  font-weight: 600;
  margin-bottom: 8px;
  font-size: 1.1em;
}

.kc-input-group input[type="text"] {
  width: 100%;
  padding: 12px 15px;
  border: 2px solid #ddd;
  border-radius: 8px;
  font-size: 1em;
  transition: border-color 0.3s ease;
}

.kc-input-group input[type="text"]:focus {
  outline: none;
  border-color: #667eea;
}

.kc-info {
  background: #f0f4ff;
  padding: 15px;
  border-radius: 8px;
  border-left: 4px solid #667eea;
  color: #333;
  font-size: 1em;
}

.kc-info-small {
  font-size: 0.9em;
  color: #999;
  font-style: italic;
  text-align: center;
}

.kc-btn-primary {
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: white;
  border: none;
  padding: 15px 40px;
  font-size: 1.1em;
  font-weight: 600;
  border-radius: 10px;
  cursor: pointer;
  transition: all 0.3s ease;
  display: block;
  margin: 20px auto 0;
}

.kc-btn-primary:hover:not(:disabled) {
  background: linear-gradient(135deg, #5568d3 0%, #6a4291 100%);
  transform: translateY(-2px);
  box-shadow: 0 6px 16px rgba(102, 126, 234, 0.4);
}

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

.kc-btn-secondary {
  background: #f5f5f5;
  color: #667eea;
  border: 2px solid #667eea;
  padding: 12px 30px;
  font-size: 1em;
  font-weight: 600;
  border-radius: 10px;
  cursor: pointer;
  transition: all 0.3s ease;
}

.kc-btn-secondary:hover:not(:disabled) {
  background: #667eea;
  color: white;
}

.kc-btn-secondary:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  border-color: #ddd;
  color: #999;
}

/* Progress Bar */
.kc-progress-bar {
  width: 100%;
  height: 8px;
  background: #f0f0f0;
  border-radius: 4px;
  overflow: hidden;
  margin-bottom: 10px;
}

.kc-progress-fill {
  height: 100%;
  background: linear-gradient(135deg, #11998e 0%, #38ef7d 100%);
  transition: width 0.3s ease;
  width: 0%;
}

.kc-progress-text {
  text-align: center;
  color: #667eea;
  font-weight: 600;
  margin-bottom: 25px;
}

/* Question Container */
.kc-question-container {
  margin: 30px 0;
}

.kc-question {
  color: #333;
  font-size: 1.2em;
  margin-bottom: 20px;
  line-height: 1.5;
}

.kc-options {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.kc-option {
  padding: 15px 20px;
  background: #f8f8f8;
  border: 2px solid #ddd;
  border-radius: 10px;
  cursor: pointer;
  transition: all 0.3s ease;
  font-size: 1em;
  text-align: left;
}

.kc-option:hover {
  background: #f0f4ff;
  border-color: #667eea;
}

.kc-option.selected {
  background: #667eea;
  color: white;
  border-color: #667eea;
}

/* Navigation */
.kc-navigation {
  display: flex;
  gap: 15px;
  justify-content: center;
  margin-top: 30px;
}

/* Results */
.kc-results-icon {
  font-size: 4em;
  text-align: center;
  margin-bottom: 20px;
}

.kc-score-display {
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: white;
  padding: 30px;
  border-radius: 12px;
  text-align: center;
  margin: 30px 0;
}

.kc-score-value {
  font-size: 3em;
  font-weight: 700;
  margin-bottom: 10px;
}

.kc-score-percent {
  font-size: 1.5em;
  opacity: 0.9;
}

.kc-results-message {
  background: #f0f4ff;
  padding: 15px;
  border-radius: 8px;
  border-left: 4px solid #667eea;
}

/* ===== FEEDBACK STYLES ===== */

.feedback-modal h2,
.final-feedback-modal h2 {
  color: #667eea;
  font-size: 1.8em;
  margin-bottom: 10px;
  text-align: center;
}

.fb-subtitle,
.ff-subtitle {
  color: #666;
  text-align: center;
  margin-bottom: 25px;
  font-size: 1em;
}

.fb-input-group,
.ff-input-group {
  margin: 20px 0;
}

.fb-input-group label,
.ff-input-group label {
  display: block;
  color: #333;
  font-weight: 600;
  margin-bottom: 8px;
  font-size: 1em;
}

.required {
  color: #dc3545;
}

.fb-input-group input[type="text"],
.ff-input-group input[type="text"] {
  width: 100%;
  padding: 12px 15px;
  border: 2px solid #ddd;
  border-radius: 8px;
  font-size: 1em;
  transition: border-color 0.3s ease;
}

.fb-input-group input[type="text"]:focus,
.ff-input-group input[type="text"]:focus {
  outline: none;
  border-color: #667eea;
}

.fb-input-group textarea,
.ff-input-group textarea {
  width: 100%;
  padding: 12px 15px;
  border: 2px solid #ddd;
  border-radius: 8px;
  font-size: 1em;
  font-family: inherit;
  resize: vertical;
  min-height: 100px;
  transition: border-color 0.3s ease;
}

.fb-input-group textarea:focus,
.ff-input-group textarea:focus {
  outline: none;
  border-color: #667eea;
}

.char-count {
  text-align: right;
  font-size: 0.9em;
  color: #999;
  margin-top: 5px;
}

/* Star Rating */
.star-rating {
  display: flex;
  gap: 5px;
  font-size: 2em;
  margin: 10px 0;
}

.star {
  cursor: pointer;
  color: #ddd;
  transition: all 0.2s ease;
  user-select: none;
}

.star:hover,
.star.selected {
  color: #ffd700;
  transform: scale(1.1);
}

/* Radio Group */
.radio-group {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin: 10px 0;
}

.radio-label {
  display: flex;
  align-items: center;
  padding: 12px 15px;
  background: #f8f8f8;
  border: 2px solid #ddd;
  border-radius: 8px;
  cursor: pointer;
  transition: all 0.3s ease;
}

.radio-label:hover {
  background: #f0f4ff;
  border-color: #667eea;
}

.radio-label input[type="radio"] {
  margin-right: 10px;
  cursor: pointer;
}

.radio-label input[type="radio"]:checked + span {
  color: #667eea;
  font-weight: 600;
}

/* Error Messages */
.fb-error,
.ff-error {
  background: #fff0f0;
  color: #dc3545;
  padding: 12px 15px;
  border-radius: 8px;
  border-left: 4px solid #dc3545;
  margin: 15px 0;
}

/* Buttons */
.fb-buttons,
.ff-buttons {
  display: flex;
  gap: 15px;
  justify-content: center;
  margin-top: 30px;
}

.fb-btn-primary,
.ff-btn-primary {
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: white;
  border: none;
  padding: 15px 40px;
  font-size: 1.1em;
  font-weight: 600;
  border-radius: 10px;
  cursor: pointer;
  transition: all 0.3s ease;
}

.fb-btn-primary:hover,
.ff-btn-primary:hover {
  background: linear-gradient(135deg, #5568d3 0%, #6a4291 100%);
  transform: translateY(-2px);
  box-shadow: 0 6px 16px rgba(102, 126, 234, 0.4);
}

.fb-btn-secondary {
  background: #f5f5f5;
  color: #667eea;
  border: 2px solid #667eea;
  padding: 15px 40px;
  font-size: 1.1em;
  font-weight: 600;
  border-radius: 10px;
  cursor: pointer;
  transition: all 0.3s ease;
}

.fb-btn-secondary:hover {
  background: #667eea;
  color: white;
}

/* Success Messages */
.fb-success,
.ff-success {
  text-align: center;
  padding: 20px;
}

.success-icon {
  font-size: 4em;
  margin-bottom: 20px;
}

.fb-success h3,
.ff-success h3 {
  color: #28a745;
  font-size: 1.8em;
  margin-bottom: 15px;
}

.fb-success p,
.ff-success p {
  color: #666;
  font-size: 1.1em;
  line-height: 1.6;
}

.ff-success-final {
  color: #667eea;
  font-weight: 600;
  margin-top: 15px;
}

/* Feedback Prompt Banner */
.feedback-prompt {
  position: fixed;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  background: linear-gradient(135deg, #f39c12 0%, #e67e22 100%);
  color: white;
  padding: 30px 40px;
  border-radius: 16px;
  box-shadow: 0 10px 40px rgba(243, 156, 18, 0.5);
  z-index: 9999;
  animation:
    popInAndPulse 0.5s ease,
    gentlePulse 2s ease-in-out 0.5s infinite;
  max-width: 500px;
  width: 90%;
  text-align: center;
}

@keyframes popInAndPulse {
  from {
    transform: translate(-50%, -50%) scale(0.8);
    opacity: 0;
  }
  to {
    transform: translate(-50%, -50%) scale(1);
    opacity: 1;
  }
}

@keyframes gentlePulse {
  0%,
  100% {
    transform: translate(-50%, -50%) scale(1);
    box-shadow: 0 10px 40px rgba(243, 156, 18, 0.5);
  }
  50% {
    transform: translate(-50%, -50%) scale(1.02);
    box-shadow: 0 12px 45px rgba(243, 156, 18, 0.6);
  }
}

.feedback-prompt p {
  margin: 0 0 15px 0;
  font-size: 1.1em;
  font-weight: 600;
}

.prompt-buttons {
  display: flex;
  gap: 15px;
  justify-content: center;
}

.prompt-btn-primary {
  background: white;
  color: #e67e22;
  border: none;
  padding: 12px 30px;
  font-size: 1.05em;
  font-weight: 700;
  border-radius: 10px;
  cursor: pointer;
  transition: all 0.3s ease;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
}

.prompt-btn-primary:hover {
  background: #fff5e6;
  transform: translateY(-2px);
  box-shadow: 0 6px 16px rgba(0, 0, 0, 0.2);
  color: #d35400;
}

.prompt-btn-secondary {
  background: rgba(255, 255, 255, 0.15);
  color: white;
  border: 2px solid white;
  padding: 12px 30px;
  font-size: 1.05em;
  font-weight: 600;
  border-radius: 10px;
  cursor: pointer;
  transition: all 0.3s ease;
}

.prompt-btn-secondary:hover {
  background: rgba(255, 255, 255, 0.25);
  transform: translateY(-2px);
}

/* ===== MOBILE RESPONSIVE ===== */

@media (max-width: 768px) {
  .modal-content {
    padding: 25px;
    width: 95%;
  }

  .knowledge-check-btn {
    font-size: 0.9em;
    padding: 10px 20px;
  }

  .kc-screen h2,
  .feedback-modal h2,
  .final-feedback-modal h2 {
    font-size: 1.5em;
  }

  .star-rating {
    font-size: 1.5em;
  }

  .fb-buttons,
  .ff-buttons {
    flex-direction: column;
  }

  .fb-btn-primary,
  .fb-btn-secondary,
  .ff-btn-primary {
    width: 100%;
  }

  .kc-navigation {
    flex-direction: column;
  }

  .kc-btn-primary,
  .kc-btn-secondary {
    width: 100%;
  }

  .feedback-prompt {
    width: 85%;
    padding: 25px 20px;
  }

  .prompt-buttons {
    flex-direction: column;
    gap: 10px;
  }

  .prompt-btn-primary,
  .prompt-btn-secondary {
    width: 100%;
  }
}

@media (max-width: 480px) {
  .modal-content {
    padding: 20px;
  }

  .kc-score-value {
    font-size: 2.5em;
  }

  .star-rating {
    font-size: 1.3em;
  }
}

/* ============================================
   KNOWLEDGE CHECK SECTION (ADDITIONAL STYLING)
   ============================================ */

.knowledge-check-section {
  text-align: center;
  margin: 40px auto 50px;
  padding: 30px 20px;
  background: linear-gradient(
    135deg,
    rgba(102, 126, 234, 0.1) 0%,
    rgba(118, 75, 162, 0.1) 100%
  );
  border-radius: 16px;
  max-width: 600px;
}

.knowledge-check-section .knowledge-check-btn {
  margin: 0 auto 15px;
  display: block;
}

.kc-description {
  color: #667eea;
  font-size: 0.95em;
  font-weight: 500;
  margin: 0;
}

@media (max-width: 768px) {
  .knowledge-check-section {
    margin: 30px 20px 40px;
    padding: 20px 15px;
  }
}

/* ===========================
   UNIT 6 - PDP STYLES
   =========================== */

/* ===========================
   UNIT 6 PDP STYLES - COMPLETE
   =========================== */

/* PDP Button on Unit Card - SAME SIZE AS QUIZ BUTTON */
.pdp-btn {
  flex: 1;
  padding: 12px 20px;
  font-size: 1em;
  font-weight: 600;
  background: linear-gradient(135deg, #ff9500 0%, #ff5e3a 100%);
  color: white;
  border: none;
  border-radius: 10px;
  cursor: pointer;
  transition: all 0.3s ease;
  box-shadow: 0 4px 12px rgba(255, 149, 0, 0.3);
}

.pdp-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 16px rgba(255, 149, 0, 0.4);
}

/* PDP View Container */
.pdp-view {
  background: linear-gradient(135deg, #1a1a2e 0%, #16213e 100%);
  max-width: 1200px;
  width: 100%;
  padding: 40px 20px;
  border-radius: 20px;
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.3);
}

.pdp-header {
  text-align: center;
  margin-bottom: 40px;
}

.pdp-header h2 {
  color: white;
  font-size: 2.2em;
  margin-bottom: 10px;
  text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.3);
}

.pdp-subtitle {
  color: rgba(255, 255, 255, 0.7);
  font-size: 1.2em;
}

/* ===========================
   PAGE 1: SECTION CHOOSER
   =========================== */

.section-chooser {
  width: 100%;
}

.section-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
  max-width: 1000px;
  margin: 0 auto;
}

.section-card {
  background: #2a2a3e;
  padding: 32px 24px;
  border-radius: 16px;
  cursor: pointer;
  transition: all 0.3s ease;
  border: 2px solid transparent;
  text-align: center;
}

.section-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.4);
  border-color: rgba(255, 255, 255, 0.2);
  background: #323248;
}

.section-icon {
  font-size: 3em;
  margin-bottom: 16px;
}

.section-card h3 {
  color: white;
  font-size: 1.1em;
  margin-bottom: 8px;
  font-weight: 600;
}

.section-title {
  color: #4fc3f7;
  font-size: 1.1em;
  font-weight: 600;
  margin-bottom: 12px;
}

.section-description {
  color: rgba(255, 255, 255, 0.7);
  font-size: 0.95em;
  line-height: 1.5;
}

/* Mobile: Stack cards */
@media (max-width: 768px) {
  .section-grid {
    grid-template-columns: 1fr;
  }
}

/* ===========================
   PAGE 2: METHOD CHOOSER
   =========================== */

.method-chooser {
  width: 100%;
}

.method-header {
  text-align: center;
  margin-bottom: 32px;
}

.back-link {
  background: transparent;
  border: none;
  color: #4fc3f7;
  font-size: 1em;
  cursor: pointer;
  margin-bottom: 16px;
  transition: color 0.3s ease;
}

.back-link:hover {
  color: #81d4fa;
  text-decoration: underline;
}

.method-header h2 {
  color: white;
  font-size: 2em;
  margin-bottom: 8px;
}

.method-subtitle {
  color: rgba(255, 255, 255, 0.7);
  font-size: 1.1em;
}

.method-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
  max-width: 900px;
  margin: 0 auto;
}

.method-card {
  background: #2a2a3e;
  padding: 32px 24px;
  border-radius: 16px;
  text-align: center;
  transition: all 0.3s ease;
  border: 2px solid transparent;
  cursor: pointer;
}

.method-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.4);
  border-color: rgba(255, 255, 255, 0.2);
}

.method-card .card-icon {
  font-size: 3.5em;
  margin-bottom: 16px;
}

.method-card h3 {
  color: white;
  font-size: 1.5em;
  margin-bottom: 12px;
}

.method-card .card-description {
  color: rgba(255, 255, 255, 0.7);
  font-size: 1em;
  margin-bottom: 20px;
}

.card-features {
  list-style: none;
  padding: 0;
  margin: 20px 0;
  text-align: left;
}

.card-features li {
  color: rgba(255, 255, 255, 0.8);
  padding: 8px 0;
  font-size: 0.95em;
}

.card-btn {
  width: 100%;
  padding: 14px 24px;
  border: none;
  border-radius: 8px;
  font-size: 1.05em;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s ease;
  margin-top: 8px;
}

.card-btn-ai {
  background: linear-gradient(135deg, #9c27b0 0%, #7b1fa2 100%);
  color: white;
  box-shadow: 0 4px 6px rgba(156, 39, 176, 0.3);
}

.card-btn-ai:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 12px rgba(156, 39, 176, 0.4);
}

.card-btn-print {
  background: linear-gradient(135deg, #4caf50 0%, #388e3c 100%);
  color: white;
  box-shadow: 0 4px 6px rgba(76, 175, 80, 0.3);
}

.card-btn-print:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 12px rgba(76, 175, 80, 0.4);
}

@media (max-width: 768px) {
  .method-grid {
    grid-template-columns: 1fr;
  }
}

/* ===========================
   PAGE 3: PROMPT DISPLAY
   =========================== */

.prompt-display {
  width: 100%;
  max-width: 900px;
  margin: 0 auto;
}

.prompt-header {
  text-align: center;
  margin-bottom: 32px;
}

.prompt-header h2 {
  color: white;
  font-size: 2em;
  margin-bottom: 8px;
}

.prompt-subtitle {
  color: rgba(255, 255, 255, 0.7);
  font-size: 1em;
}

.prompt-section {
  margin-bottom: 32px;
}

.prompt-box {
  background: #2a2a3e;
  border-radius: 12px;
  padding: 16px;
  margin-bottom: 16px;
}

.prompt-box textarea {
  width: 100%;
  min-height: 400px;
  background: #1a1a2e;
  color: white;
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: 8px;
  padding: 16px;
  font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
  font-size: 0.95em;
  line-height: 1.6;
  resize: vertical;
}

.prompt-box textarea:focus {
  outline: none;
  border-color: #4fc3f7;
}

.copy-prompt-btn {
  width: 100%;
  padding: 16px 24px;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: white;
  border: none;
  border-radius: 8px;
  font-size: 1.1em;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s ease;
  box-shadow: 0 4px 12px rgba(102, 126, 234, 0.3);
}

.copy-prompt-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 16px rgba(102, 126, 234, 0.4);
}

/* ===========================
   PAGE 4: AI PLATFORM SELECTION
   =========================== */

.ai-platform-section {
  margin-top: 40px;
  padding-top: 32px;
  border-top: 2px solid rgba(255, 255, 255, 0.1);
}

.ai-platform-section h3 {
  color: white;
  font-size: 1.8em;
  text-align: center;
  margin-bottom: 8px;
}

.platform-subtitle {
  color: rgba(255, 255, 255, 0.7);
  text-align: center;
  margin-bottom: 24px;
  font-size: 1em;
}

.ai-platform-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
  max-width: 800px;
  margin: 0 auto 24px;
}

.ai-platform-card {
  background: #2a2a3e;
  padding: 24px;
  border-radius: 12px;
  text-align: center;
  cursor: pointer;
  transition: all 0.3s ease;
  border: 2px solid transparent;
}

.ai-platform-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.4);
  border-color: rgba(255, 255, 255, 0.2);
  background: #323248;
}

.platform-logo {
  width: 60px;
  height: 60px;
  margin-bottom: 12px;
  object-fit: contain;
}

.ai-platform-card h4 {
  color: white;
  font-size: 1.3em;
  margin-bottom: 6px;
}

.ai-platform-card .platform-subtitle {
  color: rgba(255, 255, 255, 0.6);
  font-size: 0.9em;
  margin-bottom: 16px;
}

.platform-btn {
  width: 100%;
  padding: 12px 20px;
  border: none;
  border-radius: 8px;
  font-size: 1em;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s ease;
  color: white;
}

.platform-chatgpt {
  background: #10a37f;
  box-shadow: 0 4px 6px rgba(16, 163, 127, 0.3);
}

.platform-chatgpt:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 12px rgba(16, 163, 127, 0.4);
}

.platform-claude {
  background: #d97757;
  box-shadow: 0 4px 6px rgba(217, 119, 87, 0.3);
}

.platform-claude:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 12px rgba(217, 119, 87, 0.4);
}

.platform-gemini {
  background: linear-gradient(
    135deg,
    #4285f4 0%,
    #34a853 50%,
    #fbbc05 75%,
    #ea4335 100%
  );
  box-shadow: 0 4px 6px rgba(66, 133, 244, 0.3);
}

.platform-gemini:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 12px rgba(66, 133, 244, 0.4);
}

.platform-deepseek {
  background: #0066cc;
  box-shadow: 0 4px 6px rgba(0, 102, 204, 0.3);
}

.platform-deepseek:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 12px rgba(0, 102, 204, 0.4);
}

.platform-note {
  text-align: center;
  color: rgba(255, 255, 255, 0.7);
  font-size: 0.95em;
  padding: 16px;
  background: rgba(255, 255, 255, 0.05);
  border-radius: 8px;
  max-width: 800px;
  margin: 0 auto;
}

@media (max-width: 768px) {
  .ai-platform-grid {
    grid-template-columns: 1fr;
  }
}

/* ===========================
   PAGE 5: SUCCESS SCREEN
   =========================== */

.ai-success-message {
  margin-top: 40px;
  padding: 32px;
  background: rgba(76, 175, 80, 0.1);
  border: 2px solid rgba(76, 175, 80, 0.3);
  border-radius: 16px;
  display: flex;
  justify-content: center;
  align-items: center;
}

.success-content {
  text-align: center;
  width: 100%;
  max-width: 900px;
  margin: 0 auto;
}

.success-icon {
  font-size: 4em;
  color: #4caf50;
  margin-bottom: 16px;
  width: 80px;
  height: 80px;
  background: rgba(76, 175, 80, 0.2);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 20px;
}

.ai-success-message h3 {
  color: white;
  font-size: 2em;
  margin-bottom: 12px;
}

.success-subtitle {
  color: rgba(255, 255, 255, 0.8);
  font-size: 1.2em;
  margin-bottom: 24px;
}

.next-steps {
  background: #2a3f4e;
  padding: 32px 40px;
  border-radius: 12px;
  margin: 24px auto;
  width: fit-content;
  min-width: 600px;
  max-width: 850px;
  text-align: center;
}

.next-steps h4 {
  color: white;
  font-size: 1.3em;
  margin-bottom: 20px;
  text-align: center;
}

.next-steps ol {
  color: rgba(255, 255, 255, 0.9);
  padding: 0;
  margin: 0;
  list-style: none;
  counter-reset: item;
  display: inline-block;
  text-align: left;
}

.next-steps ol li {
  margin-bottom: 16px;
  font-size: 1.05em;
  line-height: 1.6;
  counter-increment: item;
  position: relative;
  padding-left: 35px;
}

.next-steps ol li:before {
  content: counter(item) ".";
  position: absolute;
  left: 0;
  font-weight: 600;
  color: rgba(255, 255, 255, 0.9);
}

.success-btn {
  padding: 16px 32px;
  background: linear-gradient(135deg, #2196f3 0%, #1976d2 100%);
  color: white;
  border: none;
  border-radius: 8px;
  font-size: 1.1em;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s ease;
  margin-top: 16px;
  box-shadow: 0 4px 6px rgba(33, 150, 243, 0.3);
}

.success-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 12px rgba(33, 150, 243, 0.4);
}

/* ===========================
   MOBILE RESPONSIVE STYLES - PDP PAGES
   Match homepage font sizes on mobile devices
   =========================== */

@media (max-width: 768px) {
  /* PDP Main Header - Match Homepage */
  .pdp-header h2 {
    font-size: 1.5em !important; /* Match homepage main heading */
  }

  .pdp-subtitle {
    font-size: 0.95em !important; /* Match homepage subtitle */
  }

  /* Section Cards - Match Homepage Unit Cards */
  .section-card h3 {
    font-size: 1em !important; /* Match homepage unit card headings */
  }

  .section-title {
    font-size: 0.95em !important; /* Match homepage card titles */
  }

  .section-description {
    font-size: 0.85em !important; /* Match homepage card descriptions */
  }

  .section-icon {
    font-size: 2em !important; /* Smaller icons on mobile */
  }

  /* Method Chooser Page - Match Homepage */
  .method-header h2 {
    font-size: 1.4em !important;
  }

  .method-subtitle {
    font-size: 0.9em !important;
  }

  .method-card h3 {
    font-size: 1.2em !important;
  }

  .method-card .card-description {
    font-size: 0.9em !important;
  }

  .method-card .card-features li {
    font-size: 0.85em !important;
  }

  .method-card .card-icon {
    font-size: 2.5em !important;
  }

  /* Prompt Display Page - Match Homepage */
  .prompt-header h2 {
    font-size: 1.4em !important;
  }

  .prompt-subtitle {
    font-size: 0.9em !important;
  }

  /* AI Platform Section */
  .ai-platform-section h3 {
    font-size: 1.3em !important;
  }

  .platform-subtitle {
    font-size: 0.85em !important;
  }

  .ai-platform-card h4 {
    font-size: 1.1em !important;
  }

  .ai-platform-card .platform-subtitle {
    font-size: 0.8em !important;
  }

  .platform-logo {
    width: 50px !important;
    height: 50px !important;
  }

  .platform-note {
    font-size: 0.85em !important;
  }

  /* Success Screen - Match Homepage */
  .ai-success-message h3 {
    font-size: 1.4em !important;
  }

  .success-subtitle {
    font-size: 1em !important;
  }

  /* What to do next Card - FIT ON SCREEN */
  .next-steps {
    min-width: auto !important;
    max-width: 100% !important; /* Full width */
    width: calc(100% - 8px) !important; /* Only 4px margin each side */
    padding: 16px 8px !important; /* Absolute minimum padding = MAXIMUM text */
    margin: 12px auto !important;
  }

  .next-steps h4 {
    font-size: 1.1em !important;
    margin-bottom: 12px !important;
    padding: 0 2px !important;
  }

  .next-steps ol {
    padding-left: 0 !important;
    margin: 0 !important;
  }

  .next-steps ol li {
    font-size: 0.85em !important; /* Smaller font = more text per line */
    margin-bottom: 8px !important;
    line-height: 1.35 !important; /* Tighter line spacing */
    padding-left: 20px !important; /* Minimal space for numbers = MAX text space */
  }

  .next-steps ol li:before {
    left: 2px !important; /* Numbers very close to edge */
  }

  .next-steps ol li:last-child {
    margin-bottom: 0 !important;
  }

  /* Build Your PDP Button - Match Other Buttons */
  .pdp-btn {
    font-size: 1em;
    padding: 12px 20px;
  }

  /* All Card Buttons on Mobile */
  .card-btn {
    font-size: 0.95em !important;
    padding: 12px 20px !important;
  }

  /* Copy Prompt Button */
  .copy-prompt-btn {
    font-size: 1em !important;
    padding: 14px 20px !important;
  }

  /* Platform Buttons */
  .platform-btn {
    font-size: 0.9em !important;
    padding: 10px 16px !important;
  }

  /* Success Go Back Button */
  .success-btn {
    font-size: 1em !important;
    padding: 14px 28px !important;
  }

  /* Back Links */
  .back-link {
    font-size: 0.9em !important;
  }

  /* General PDP View Container */
  .pdp-view {
    padding: 24px 16px !important;
  }

  /* Prompt Box Textarea */
  .prompt-box textarea {
    font-size: 0.85em !important;
    min-height: 300px !important; /* Smaller on mobile */
  }

  /* Warning Modal on Mobile */
  .copy-warning-modal {
    max-width: 90% !important;
    margin: 20px !important;
  }

  .copy-warning-modal h2 {
    font-size: 1.3em !important;
  }

  .copy-warning-modal .warning-message {
    font-size: 0.95em !important;
  }

  .copy-warning-modal .warning-note {
    font-size: 0.85em !important;
  }

  .warning-icon {
    font-size: 3em !important;
  }
}

/* Modal styles removed - Go Back is now simple button navigation */

/* ===========================
   COPY WARNING MODAL
   =========================== */

.copy-warning-modal {
  max-width: 500px;
  background: white;
  padding: 0;
}

.copy-warning-modal .modal-close {
  position: absolute;
  top: 20px;
  right: 20px;
  background: transparent;
  border: none;
  font-size: 2em;
  color: #666;
  cursor: pointer;
  line-height: 1;
  padding: 0;
  width: 40px;
  height: 40px;
}

.copy-warning-modal .modal-close:hover {
  color: #333;
}

.copy-warning-modal .warning-header {
  text-align: center;
  padding: 32px 32px 16px;
}

.copy-warning-modal .warning-icon {
  font-size: 4em;
  margin-bottom: 16px;
}

.copy-warning-modal h2 {
  color: #333;
  font-size: 1.5em;
  margin-bottom: 0;
  font-weight: 600;
}

.copy-warning-modal .warning-message {
  color: #555;
  font-size: 1.05em;
  margin: 16px 32px;
  line-height: 1.6;
  text-align: center;
}

.copy-warning-modal .warning-note {
  color: #777;
  font-size: 0.95em;
  margin: 0 32px 24px;
  line-height: 1.5;
  text-align: center;
}

.warning-btn {
  width: calc(100% - 64px);
  margin: 0 32px 32px;
  padding: 14px 32px;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: white;
  border: none;
  border-radius: 8px;
  font-size: 1.1em;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s ease;
  box-shadow: 0 4px 12px rgba(102, 126, 234, 0.3);
}

.warning-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 16px rgba(102, 126, 234, 0.4);
}

.success-content .success-subtitle {
  color: rgba(255, 255, 255, 0.8);
  font-size: 1.2em;
  margin-bottom: 30px;
}

.success-btn {
  margin-top: 25px;
  padding: 15px 40px;
  background: linear-gradient(135deg, #4caf50 0%, #45a049 100%);
  color: white;
  border: none;
  border-radius: 10px;
  font-size: 1.1em;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s ease;
}

.success-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 25px rgba(76, 175, 80, 0.5);
}

/* ===========================
   VIDEO LESSONS STYLING
   =========================== */

/* Video View Container */
.video-view {
  padding: 40px 20px;
  max-width: 1000px;
  margin: 0 auto;
}

.video-view.hidden {
  display: none;
}

.video-content {
  background: #2a2a3e;
  padding: 40px;
  border-radius: 16px;
  margin-top: 20px;
  min-height: 600px;
  max-width: 900px;
  margin-left: auto;
  margin-right: auto;
}

.video-content.hidden {
  display: none;
}

/* Video Header */
.video-header {
  text-align: center;
  margin-bottom: 32px;
}

.video-icon {
  font-size: 4em;
  margin-bottom: 16px;
}

.video-header h2 {
  color: white;
  font-size: 1.4em;
  margin: 0;
  font-weight: 600;
}

/* Video Introduction */
.video-intro {
  margin-bottom: 32px;
  line-height: 1.6;
}

.video-intro p {
  color: rgba(255, 255, 255, 0.9);
  margin-bottom: 12px;
}

.video-intro ul {
  list-style: none;
  padding-left: 24px;
}

.video-intro ul li {
  color: rgba(255, 255, 255, 0.9);
  margin-bottom: 6px;
  position: relative;
  line-height: 1.4;
}

.video-intro ul li:before {
  content: "•";
  position: absolute;
  left: -20px;
  color: rgba(255, 255, 255, 0.6);
}

.warning-text {
  color: #ff9800;
  font-weight: 600;
  margin-top: 20px !important;
}

/* Video Sections */
.video-sections {
  margin-bottom: 32px;
}

.video-sections h3 {
  color: white;
  font-size: 1.2em;
  margin-bottom: 20px;
  font-weight: 600;
}

.video-section {
  margin-bottom: 20px;
}

.video-section h4 {
  color: rgba(255, 255, 255, 0.95);
  font-size: 1.1em;
  margin-bottom: 10px;
  font-weight: 600;
}

.video-section ul {
  list-style: none;
  padding-left: 24px;
}

.video-section ul li {
  color: rgba(255, 255, 255, 0.85);
  margin-bottom: 6px;
  line-height: 1.4;
  position: relative;
}

.video-section ul li:before {
  content: "•";
  position: absolute;
  left: -20px;
  color: rgba(255, 255, 255, 0.5);
}

/* Video Redirect Text */
.video-redirect {
  text-align: center;
  margin: 32px 0;
}

.video-redirect p {
  color: #667eea;
  font-size: 1.1em;
  margin-bottom: 8px;
  font-weight: 500;
}

/* Watch Playlist Button - BLUE YouTube Style */
.watch-playlist-btn {
  display: block;
  width: 100%;
  max-width: 500px;
  margin: 32px auto;
  padding: 18px 32px;
  background: linear-gradient(135deg, #4285f4 0%, #1967d2 100%);
  color: white;
  border: none;
  border-radius: 12px;
  font-size: 1.3em;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s ease;
  box-shadow: 0 4px 12px rgba(66, 133, 244, 0.3);
}

.watch-playlist-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 16px rgba(66, 133, 244, 0.4);
  background: linear-gradient(135deg, #5294f5 0%, #2977e2 100%);
}

/* Video Duration Text */
.video-duration {
  text-align: center;
  color: #667eea;
  font-size: 1em;
  margin: 16px 0 32px;
  font-weight: 500;
}

/* Back Button Bottom */
.back-btn-bottom {
  display: block;
  margin: 32px auto 0;
  padding: 12px 24px;
  background: transparent;
  color: rgba(255, 255, 255, 0.8);
  border: 2px solid rgba(255, 255, 255, 0.3);
  border-radius: 8px;
  font-size: 1em;
  cursor: pointer;
  transition: all 0.3s ease;
}

.back-btn-bottom:hover {
  background: rgba(255, 255, 255, 0.1);
  border-color: rgba(255, 255, 255, 0.5);
  color: white;
}

/* Video Button on Unit Cards - BLUE YouTube Style */
.video-btn {
  background: linear-gradient(135deg, #4285f4 0%, #1967d2 100%);
  box-shadow: 0 4px 6px rgba(66, 133, 244, 0.3);
  color: white;
}

.video-btn:hover {
  background: linear-gradient(135deg, #5294f5 0%, #2977e2 100%);
  box-shadow: 0 6px 12px rgba(66, 133, 244, 0.4);
  transform: translateY(-2px);
}

/* Flashcard Button - ORIGINAL GREEN */
.flashcard-btn {
  background: linear-gradient(135deg, #11998e 0%, #38ef7d 100%);
  color: white;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
}

.flashcard-btn:hover {
  background: linear-gradient(135deg, #0d7a6e 0%, #2ed968 100%);
  transform: translateY(-2px);
  box-shadow: 0 6px 16px rgba(17, 153, 142, 0.4);
}

/* 3-Button Layout on Unit Cards */
.unit-buttons {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-top: 20px;
}

.unit-btn {
  padding: 12px 20px;
  border: none;
  border-radius: 10px;
  font-size: 1em;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s ease;
}

/* Desktop: 3 buttons in a row */
@media (min-width: 769px) {
  .unit-buttons {
    flex-direction: row;
    gap: 8px;
  }

  .unit-btn {
    flex: 1;
    padding: 12px 8px;
    font-size: 1em;
  }
}

/* Mobile: Stack vertically */
@media (max-width: 768px) {
  .video-content {
    padding: 24px 20px;
  }

  .video-header h2 {
    font-size: 1.2em;
  }

  .video-icon {
    font-size: 3em;
  }

  .video-sections h3 {
    font-size: 1.1em;
  }

  .video-section h4 {
    font-size: 1em;
  }

  .watch-playlist-btn {
    font-size: 1.1em;
    padding: 16px 24px;
  }

  .unit-buttons {
    flex-direction: column;
  }

  .unit-btn {
    width: 100%;
    padding: 12px 20px;
    font-size: 1em;
  }
}

/* Ensure study-btn has same styling as flashcard-btn */
.study-btn {
  background: linear-gradient(135deg, #11998e 0%, #38ef7d 100%);
  color: white;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
  padding: 12px 20px;
  font-size: 1em;
  font-weight: 600;
  border: none;
  border-radius: 10px;
  cursor: pointer;
  transition: all 0.3s ease;
}

.study-btn:hover {
  background: linear-gradient(135deg, #0d7a6e 0%, #2ed968 100%);
  transform: translateY(-2px);
  box-shadow: 0 6px 16px rgba(17, 153, 142, 0.4);
}

/* ===========================
   MOBILE FLASHCARD NAVIGATION
   =========================== */

/* Mobile Navigation Buttons Container */
.mobile-nav-buttons {
  display: none; /* Hidden on desktop */
  gap: 10px;
  margin: 20px 0;
  width: 100%;
}

.mobile-nav-btn {
  flex: 1;
  padding: 14px 20px;
  min-height: 48px;
  background: rgba(255, 255, 255, 0.3);
  color: white;
  border: 1px solid rgba(255, 255, 255, 0.4);
  border-radius: 10px;
  font-size: 1.1em;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s ease;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.2);
  touch-action: manipulation; /* Better touch response */
}

.mobile-nav-btn:hover {
  background: rgba(255, 255, 255, 0.4);
  border-color: rgba(255, 255, 255, 0.5);
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
}

.mobile-nav-btn:active {
  background: rgba(255, 255, 255, 0.5);
  transform: translateY(0) scale(0.98);
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.2);
}

.mobile-nav-btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  transform: none;
}

/* Mobile: Show mobile buttons, hide desktop arrows, change tip */
@media (max-width: 768px) {
  /* Show mobile navigation buttons */
  .mobile-nav-buttons {
    display: flex;
  }

  /* Hide desktop side arrows */
  .nav-arrow {
    display: none !important;
  }

  /* Change keyboard tip text for mobile */
  .keyboard-tip {
    visibility: hidden;
    position: relative;
    height: 20px;
  }

  .keyboard-tip::after {
    content: "💡 Swipe or tap arrows to navigate";
    visibility: visible;
    position: absolute;
    left: 0;
    right: 0;
    top: 0;
    font-size: 0.95em;
    color: rgba(255, 255, 255, 0.8);
  }
}

/* Desktop: Keep everything as is */
@media (min-width: 769px) {
  .mobile-nav-buttons {
    display: none; /* Hidden on desktop */
  }

  .nav-arrow {
    display: flex; /* Keep desktop arrows */
  }

  .keyboard-tip {
    /* Original text remains */
  }
}