:root {
  --bg: #2c2c2c;
  --fg: #faf9f6;
  --accent: #3e3b37;
  --muted: #888888;
  --highlight: #e8a735;
}

body {
  background-color: var(--bg);
  color: var(--fg);
  font-family: "Caveat", "Patrick Hand", cursive;
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  margin: 0;
}

.container {
  text-align: center;
  max-width: 800px;
  width: 90%;
  margin: 20px auto;
}

h1 {
  font-size: 2.8em;
  font-weight: 700;
  letter-spacing: 1px;
  margin-bottom: 40px;
}

input[type="file"] {
  width: 0.1px;
  height: 0.1px;
  opacity: 0;
  overflow: hidden;
  position: absolute;
  z-index: -1;
}

.drop-zone {
  border: 2px dashed var(--muted);
  border-radius: 12px;
  padding: 48px 24px;
  cursor: pointer;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  transition: all 0.3s ease;
  background: transparent;
}

.drop-zone:hover,
.drop-zone.drag-over {
  border-color: var(--fg);
  background: var(--accent);
}

.drop-zone-icon {
  width: 48px;
  height: 48px;
  color: var(--muted);
  margin-bottom: 16px;
  transition: color 0.3s ease;
}

.drop-zone:hover .drop-zone-icon,
.drop-zone.drag-over .drop-zone-icon {
  color: var(--fg);
}

.drop-zone-text {
  font-size: 1.3em;
  color: var(--fg);
  margin: 0 0 4px;
}

.drop-zone-hint {
  font-size: 1em;
  color: var(--muted);
  margin: 0;
}

.drop-zone.has-file {
  border-color: var(--highlight);
}

.drop-zone.has-file .drop-zone-text {
  color: var(--highlight);
}

#uploadForm {
  display: flex;
  flex-direction: column;
}

#generateBtn {
  width: 100%;
  margin: 12px 0 0;
  box-sizing: border-box;
  background: var(--accent);
  border-color: var(--muted);
}

button {
  background: var(--bg);
  color: var(--fg);
  border: 2px solid var(--accent);
  border-radius: 8px;
  padding: 12px 24px;
  cursor: pointer;
  margin: 10px;
  font-family: inherit;
  font-size: 1.1em;
  transition: all 0.3s ease;
}

button:hover:not(.explain-btn) {
  background: var(--accent);
  border-color: var(--muted);
}

#loading {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 1000;
  background: rgba(0, 0, 0, 0.75);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 20px;
}

#loading p {
  letter-spacing: 2px;
  font-size: 1.4em;
  color: #ffffff;
}

#loadingTimer {
  font-size: 1.1em;
  color: rgba(255, 255, 255, 0.5);
  margin: 0;
}

.spinner {
  width: 40px;
  height: 40px;
  border: 3px solid rgba(255, 255, 255, 0.2);
  border-top: 3px solid #ffffff;
  border-radius: 50%;
  animation: spin 1s linear infinite;
  margin: 0 auto 10px;
}

#playSnakeBtn {
  background: transparent;
  color: rgba(255, 255, 255, 0.6);
  border: 1px solid rgba(255, 255, 255, 0.3);
  border-radius: 8px;
  padding: 10px 22px;
  cursor: pointer;
  font-family: "Caveat", "Patrick Hand", cursive;
  font-size: 1.1em;
  transition: all 0.3s ease;
  margin-top: 10px;
}

#playSnakeBtn:hover {
  color: #ffffff;
  border-color: rgba(255, 255, 255, 0.6);
  background: rgba(255, 255, 255, 0.08);
}

#snakeGame {
  display: none;
  flex-direction: column;
  align-items: center;
  gap: 12px;
}

#snakeGame canvas {
  border: 2px solid rgba(255, 255, 255, 0.25);
  border-radius: 8px;
  background: rgba(0, 0, 0, 0.4);
}

#snakeScore {
  color: rgba(255, 255, 255, 0.6);
  font-family: "Caveat", "Patrick Hand", cursive;
  font-size: 1.1em;
  letter-spacing: 1px;
}

#snakeHeader {
  display: flex;
  justify-content: space-between;
  width: 300px;
}

#snakeTimer {
  color: rgba(255, 255, 255, 0.4);
  font-family: "Caveat", "Patrick Hand", cursive;
  font-size: 1.1em;
  letter-spacing: 1px;
}

#seeNotesBtn {
  background: #ffffff;
  color: #111111;
  border: none;
  border-radius: 8px;
  padding: 12px 28px;
  cursor: pointer;
  font-family: "Caveat", "Patrick Hand", cursive;
  font-size: 1.3em;
  font-weight: 600;
  transition: all 0.3s ease;
  animation: pulseBtn 2s ease-in-out infinite;
  margin: 0;
}

#seeNotesBtn:hover {
  transform: scale(1.05);
  background: #f0f0f0;
}

@keyframes pulseBtn {
  0%,
  100% {
    box-shadow: 0 0 0 0 rgba(255, 255, 255, 0.4);
  }
  50% {
    box-shadow: 0 0 0 8px rgba(255, 255, 255, 0);
  }
}

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

#results {
  margin-top: 40px;
  text-align: left;
  font-family: "Caveat", "Patrick Hand", cursive;
  line-height: 1.8;
  font-size: 1.15rem;
  display: none;
}

#results h1,
#results h2,
#results h3 {
  margin-top: 1.5em;
  margin-bottom: 0.5em;
  font-family: "Caveat", "Patrick Hand", cursive;
  font-weight: 700;
  letter-spacing: 0.5px;
  border-bottom: none;
  padding-bottom: 0;
  display: inline;
  background-image: linear-gradient(var(--highlight), var(--highlight));
  background-size: 100% 30%;
  background-repeat: no-repeat;
  background-position: left 90%;
  box-decoration-break: clone;
  -webkit-box-decoration-break: clone;
}

#results h1::after,
#results h2::after,
#results h3::after {
  content: "";
  display: block;
}

#results ul,
#results ol {
  padding-left: 20px;
  margin-bottom: 1em;
}

#results li {
  margin-bottom: 0.5em;
}

#results p {
  margin-bottom: 1em;
  font-family: "Caveat", "Patrick Hand", cursive;
  font-size: 1.1em;
}

#results strong {
  font-weight: 700;
  color: var(--fg);
}

#results table {
  width: 100%;
  border-collapse: collapse;
  margin: 20px 0;
  font-family: "Caveat", "Patrick Hand", cursive;
  font-size: 1em;
}

#results th,
#results td {
  border: 1px solid var(--accent);
  padding: 12px;
  text-align: left;
}

#results th {
  background-color: var(--accent);
  font-weight: 700;
  letter-spacing: 0.5px;
}

.export-btn {
  display: block;
  margin: 20px auto 0;
  background: transparent;
  color: var(--muted);
  border: 1px solid var(--muted);
  border-radius: 6px;
  padding: 8px 20px;
  cursor: pointer;
  font-family: "Caveat", "Patrick Hand", cursive;
  font-size: 1em;
  letter-spacing: 1px;
  transition: all 0.3s ease;
}

.export-btn:hover {
  color: var(--fg);
  border-color: var(--fg);
}

#tabs {
  display: none;
  justify-content: center;
  gap: 24px;
  margin-top: 30px;
}

#studyActions {
  display: none;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  margin-top: 30px;
}

#studyActions #tabs {
  margin-top: 0;
  justify-content: flex-start;
}

#abandonBtn {
  margin: 0;
  padding: 10px 18px;
  font-size: 0.95em;
  letter-spacing: 1px;
  background: transparent;
  color: var(--muted);
  border: 1px solid var(--muted);
}

#abandonBtn:hover {
  color: var(--fg);
  border-color: var(--fg);
  background: var(--accent);
}

.tab-btn {
  background: transparent;
  color: var(--muted);
  border: none;
  padding: 0;
  cursor: pointer;
  font-family: "Caveat", "Patrick Hand", cursive;
  font-size: 1.1em;
  letter-spacing: 1px;
  transition: color 0.3s ease;
  margin: 0;
}

.tab-btn:hover {
  color: var(--fg);
  background: transparent;
}

.tab-btn.active {
  color: var(--fg);
  background: transparent;
}

#flashcardsContainer {
  margin-top: 40px;
  display: flex;
  flex-direction: column;
  align-items: center;
  width: 100%;
}

#flashcardDeck {
  perspective: 1000px;
  width: 100%;
  max-width: 500px;
  margin: 0 auto;
}

.flashcard {
  width: 100%;
  height: 280px;
  cursor: pointer;
  position: relative;
}

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

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

.flashcard-front,
.flashcard-back {
  position: absolute;
  width: 100%;
  height: 100%;
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  border: 2px solid var(--accent);
  border-radius: 12px;
  padding: 30px;
  box-sizing: border-box;
  text-align: center;
}

.flashcard-front {
  background: var(--bg);
  border-radius: 12px;
}

.flashcard-back {
  background: var(--accent);
  transform: rotateY(180deg);
  border-radius: 12px;
}

.flashcard-front p,
.flashcard-back p {
  font-family: "Caveat", "Patrick Hand", cursive;
  font-size: 1.25em;
  line-height: 1.6;
  margin: 0;
}

.flip-hint {
  position: absolute;
  bottom: 12px;
  font-size: 0.65em;
  letter-spacing: 2px;
  color: var(--muted);
}

#flashcardNav {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 20px;
  margin-top: 25px;
  width: 100%;
}

#flashcardNav button {
  font-size: 0.8em;
  padding: 8px 18px;
  letter-spacing: 2px;
}

#flashcardNav button:disabled {
  opacity: 0.3;
  cursor: not-allowed;
}

#cardCounter {
  font-family: "Caveat", "Patrick Hand", cursive;
  font-size: 1.1em;
  letter-spacing: 1px;
  color: var(--muted);
}

#quizContainer {
  margin-top: 40px;
  text-align: left;
  text-transform: none;
  width: 100%;
}

#quizScore {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 20px;
  margin-bottom: 30px;
  padding: 0 15px;
  border: 2px solid var(--accent);
  border-radius: 10px;
  height: 50px;
}

#quizScore button {
  margin: 0;
  font-size: 0.8em;
  padding: 8px 18px;
  letter-spacing: 2px;
}

#scoreText {
  font-family: "Caveat", "Patrick Hand", cursive;
  font-size: 1.3em;
  letter-spacing: 1px;
}

.quiz-question {
  margin-bottom: 20px;
  padding-bottom: 20px;
}

.quiz-question:last-child {
  border-bottom: none;
}

.quiz-question-counter {
  font-family: "Caveat", "Patrick Hand", cursive;
  font-size: 1em;
  letter-spacing: 1px;
  color: var(--muted);
  margin-bottom: 10px;
}

.quiz-question-text {
  font-family: "Caveat", "Patrick Hand", cursive;
  font-size: 1.25em;
  line-height: 1.6;
  margin-bottom: 20px;
}

.q-num {
  color: var(--muted);
  margin-right: 5px;
}

.quiz-options {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.quiz-option {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px 15px;
  border: 2px solid var(--accent);
  border-radius: 8px;
  cursor: pointer;
  transition: all 0.2s ease;
  font-family: "Caveat", "Patrick Hand", cursive;
  font-size: 1.1em;
}

.quiz-option:hover:not(.disabled) {
  border-color: var(--fg);
}

.quiz-option.disabled {
  cursor: default;
  pointer-events: none;
}

.quiz-option input[type="radio"] {
  display: none;
}

.quiz-option input[type="radio"]:checked ~ .option-letter {
  background: var(--fg);
  color: var(--bg);
}

.quiz-option input[type="radio"]:checked ~ .option-text {
  color: var(--fg);
}

.option-letter {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  border: 2px solid var(--fg);
  border-radius: 50%;
  font-size: 0.9em;
  letter-spacing: 0;
  flex-shrink: 0;
  transition: all 0.2s ease;
}

.option-text {
  color: var(--muted);
  line-height: 1.5;
  transition: color 0.2s ease;
}

.quiz-option.correct {
  border-color: #4caf50;
  background: rgba(76, 175, 80, 0.1);
}

.quiz-option.correct .option-letter {
  background: #4caf50;
  border-color: #4caf50;
  color: var(--bg);
}

.quiz-option.correct .option-text {
  color: #4caf50;
}

.correct-badge {
  margin-left: auto;
  font-size: 0.9em;
  letter-spacing: 1px;
  color: #4caf50;
  font-family: "Caveat", "Patrick Hand", cursive;
}

.quiz-option.wrong {
  border-color: #f44336;
  background: rgba(244, 67, 54, 0.1);
}

.quiz-option.wrong .option-letter {
  background: #f44336;
  border-color: #f44336;
  color: var(--bg);
}

.quiz-option.wrong .option-text {
  color: #f44336;
}

.quiz-actions {
  display: flex;
  gap: 10px;
  margin-top: 15px;
}

.explain-btn {
  margin: 0;
  display: inline-block;
  font-size: 0.95em;
  padding: 8px 18px;
  letter-spacing: 1px;
  border: 2px solid var(--accent);
  border-radius: 8px;
  color: var(--muted);
}

.explain-btn:hover {
  border-color: var(--muted);
  color: var(--fg);
  background: var(--accent);
}

.ai-explanation {
  margin-top: 20px;
  padding: 20px;
  border: 2px solid var(--accent);
  border-radius: 10px;
  font-family: "Caveat", "Patrick Hand", cursive;
  font-size: 1.1em;
  line-height: 1.7;
}

.ai-explanation p {
  margin-bottom: 0.8em;
}

.ai-explanation strong {
  color: var(--fg);
}

#chatContainer {
  margin-top: 40px;
  display: none;
  flex-direction: column;
  width: 100%;
  height: 500px;
  border: 2px solid var(--accent);
  border-radius: 12px;
  overflow: hidden;
}

#chatMessages {
  flex: 1;
  overflow-y: auto;
  padding: 20px;
  display: flex;
  flex-direction: column;
  gap: 12px;
  scrollbar-width: thin;
  scrollbar-color: var(--accent) transparent;
}

#chatMessages::-webkit-scrollbar {
  width: 4px;
}

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

#chatMessages::-webkit-scrollbar-thumb {
  background: var(--accent);
  border-radius: 2px;
}

#chatMessages::-webkit-scrollbar-thumb:hover {
  background: var(--muted);
}

.chat-message {
  max-width: 80%;
  padding: 12px 16px;
  font-family: "Caveat", "Patrick Hand", cursive;
  font-size: 1.15em;
  line-height: 1.6;
  word-wrap: break-word;
  border-radius: 12px;
}

.chat-user {
  align-self: flex-end;
  background: var(--fg);
  color: var(--bg);
  border: none;
}

.chat-assistant {
  align-self: flex-start;
  background: var(--accent);
  color: var(--fg);
  border: none;
}

.chat-assistant p {
  margin: 0 0 0.6em 0;
}

.chat-assistant p:last-child {
  margin-bottom: 0;
}

.chat-assistant ul,
.chat-assistant ol {
  padding-left: 20px;
  margin: 0.4em 0;
}

.chat-assistant strong {
  color: var(--fg);
}

.chat-assistant code {
  background: var(--accent);
  padding: 2px 5px;
  font-size: 0.9em;
}

.chat-typing {
  color: var(--muted);
  font-style: italic;
}

#chatForm {
  display: flex;
  border-top: 1px solid var(--accent);
}

#chatInput {
  flex: 1;
  background: var(--bg);
  color: var(--fg);
  border: none;
  padding: 14px 16px;
  font-family: "Caveat", "Patrick Hand", cursive;
  font-size: 1.1em;
  outline: none;
}

#chatInput::placeholder {
  color: var(--muted);
  letter-spacing: 0.5px;
  font-size: 1em;
}

#chatSendBtn {
  background: var(--bg);
  color: var(--fg);
  border: none;
  border-left: 2px solid var(--accent);
  padding: 14px 24px;
  cursor: pointer;
  font-family: "Caveat", "Patrick Hand", cursive;
  font-size: 1.1em;
  letter-spacing: 1px;
  transition: all 0.3s ease;
  margin: 0;
  border-radius: 0;
}

#chatSendBtn:hover {
  background: var(--accent);
}

.settings-gear {
  position: fixed;
  top: 20px;
  right: 20px;
  background: transparent;
  border: 2px solid var(--accent);
  border-radius: 50%;
  color: var(--muted);
  font-size: 1.4em;
  width: 42px;
  height: 42px;
  padding: 0;
  margin: 0;
  cursor: pointer;
  transition: all 0.3s ease;
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 100;
}

.settings-gear:hover {
  color: var(--fg);
  border-color: var(--muted);
  background: var(--accent);
}

@media (max-width: 700px) {
  #studyActions {
    flex-direction: column;
    align-items: stretch;
  }

  #studyActions #tabs {
    justify-content: center;
    flex-wrap: wrap;
  }

  #abandonBtn {
    width: 100%;
  }
}

.settings-panel {
  position: fixed;
  top: 72px;
  right: 20px;
  width: 280px;
  background: var(--bg);
  border: 2px solid var(--accent);
  border-radius: 12px;
  padding: 0;
  z-index: 100;
  text-align: left;
  overflow: hidden;
}

.settings-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 14px 18px;
  border-bottom: 2px solid var(--accent);
  font-size: 1.1em;
  letter-spacing: 1px;
}

.settings-close {
  background: transparent;
  border: none;
  color: var(--muted);
  font-size: 1.3em;
  cursor: pointer;
  padding: 0;
  margin: 0;
  width: auto;
  height: auto;
  line-height: 1;
}

.settings-close:hover {
  color: var(--fg);
  background: transparent;
}

.settings-section {
  padding: 18px;
  border-bottom: 2px solid var(--accent);
}

.settings-section:last-child {
  border-bottom: none;
}

.settings-label {
  display: block;
  font-size: 1em;
  letter-spacing: 0.5px;
  color: var(--muted);
  margin-bottom: 12px;
}

.color-scheme-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 8px;
}

.color-swatch {
  padding: 8px 10px;
  cursor: pointer;
  font-size: 0.9em;
  letter-spacing: 0.5px;
  text-align: center;
  transition: all 0.2s ease;
  margin: 0;
  border-radius: 6px;
}

.color-swatch:hover {
  opacity: 0.85;
}

.color-swatch.active {
  outline: 2px solid var(--fg);
  outline-offset: 2px;
  border-radius: 6px;
}

.settings-select {
  width: 100%;
  background: var(--bg);
  color: var(--fg);
  border: 2px solid var(--accent);
  border-radius: 8px;
  padding: 10px 12px;
  font-family: "Caveat", "Patrick Hand", cursive;
  font-size: 1.05em;
  letter-spacing: 0.5px;
  cursor: pointer;
  outline: none;
  appearance: none;
  -webkit-appearance: none;
}

.settings-select:focus {
  border-color: var(--fg);
}

.settings-select option {
  background: var(--bg);
  color: var(--fg);
}