/* Reset & Variables */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

:root {
  --bg-primary: #0f0f1a;
  --bg-secondary: #1a1a2e;
  --bg-card: #16162a;
  --neon-cyan: #00d4ff;
  --neon-pink: #ff6b9d;
  --neon-purple: #c084fc;
  --neon-green: #4ade80;
  --neon-red: #f87171;
  --neon-yellow: #fbbf24;
  --text-primary: #e2e8f0;
  --text-secondary: #94a3b8;
  --border-radius: 12px;
  --transition: 0.3s ease;
}

body {
  font-family: 'Inter', sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  min-height: 100vh;
  overflow-x: hidden;
}

/* Noise overlay */
.noise {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  z-index: 1000;
  opacity: 0.03;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 200 200' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='noise'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%' height='100%' filter='url(%23noise)'/%3E%3C/svg%3E");
}

/* Container */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

/* Header */
.header {
  background: rgba(26, 26, 46, 0.95);
  backdrop-filter: blur(20px);
  border-bottom: 1px solid rgba(0, 212, 255, 0.2);
  padding: 15px 0;
  position: sticky;
  top: 0;
  z-index: 100;
}

.header .container {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: center;
  gap: 15px;
}

.logo {
  font-family: 'Orbitron', sans-serif;
  font-size: 1.5rem;
  font-weight: 900;
  background: linear-gradient(135deg, var(--neon-cyan), var(--neon-purple));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  text-shadow: 0 0 30px rgba(0, 212, 255, 0.5);
}

.nav {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}

.nav-btn {
  background: var(--bg-card);
  border: 1px solid rgba(255, 255, 255, 0.1);
  color: var(--text-secondary);
  padding: 10px 16px;
  border-radius: 8px;
  cursor: pointer;
  font-size: 0.9rem;
  transition: var(--transition);
}

.nav-btn:hover {
  border-color: var(--neon-cyan);
  color: var(--neon-cyan);
}

.nav-btn.active {
  background: linear-gradient(135deg, var(--neon-cyan), var(--neon-purple));
  border-color: transparent;
  color: var(--bg-primary);
  font-weight: 600;
}

/* Main */
.main {
  padding: 30px 0 80px;
}

/* Progress Section */
.progress-section {
  background: var(--bg-card);
  border: 1px solid rgba(0, 212, 255, 0.15);
  border-radius: var(--border-radius);
  padding: 20px;
  margin-bottom: 30px;
}

.progress-info {
  display: flex;
  justify-content: space-between;
  margin-bottom: 10px;
  font-size: 0.9rem;
  color: var(--text-secondary);
}

.progress-percent {
  color: var(--neon-cyan);
  font-weight: 600;
}

.progress-bar {
  height: 8px;
  background: var(--bg-secondary);
  border-radius: 4px;
  overflow: hidden;
}

.progress-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--neon-cyan), var(--neon-purple), var(--neon-pink));
  border-radius: 4px;
  transition: width 0.5s ease;
  box-shadow: 0 0 15px var(--neon-cyan);
}

/* Section */
.section {
  display: none;
  animation: fadeIn 0.4s ease;
}

.section.active {
  display: block;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}

.section-title {
  font-family: 'Orbitron', sans-serif;
  font-size: 2rem;
  font-weight: 700;
  margin-bottom: 10px;
  background: linear-gradient(135deg, var(--neon-cyan), var(--neon-pink));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.section-desc {
  color: var(--text-secondary);
  margin-bottom: 25px;
}

/* Buttons */
.btn {
  padding: 12px 24px;
  border-radius: 8px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition);
  border: none;
}

.btn-primary {
  background: linear-gradient(135deg, var(--neon-cyan), var(--neon-purple));
  color: var(--bg-primary);
  box-shadow: 0 4px 20px rgba(0, 212, 255, 0.3);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 30px rgba(0, 212, 255, 0.5);
}

.btn-secondary {
  background: var(--bg-card);
  color: var(--text-primary);
  border: 1px solid rgba(255, 255, 255, 0.1);
}

.btn-secondary:hover {
  border-color: var(--neon-cyan);
  color: var(--neon-cyan);
}

.btn-nav {
  background: var(--bg-secondary);
  color: var(--text-secondary);
  border: 1px solid rgba(255, 255, 255, 0.1);
  padding: 8px 16px;
  font-size: 0.9rem;
}

.btn-nav:hover {
  border-color: var(--neon-purple);
  color: var(--neon-purple);
}

.btn-danger {
  background: transparent;
  color: var(--neon-red);
  border: 1px solid var(--neon-red);
  margin-top: 30px;
}

.btn-danger:hover {
  background: var(--neon-red);
  color: var(--bg-primary);
}

/* Cards Controls */
.cards-controls {
  display: flex;
  gap: 10px;
  margin-bottom: 25px;
  flex-wrap: wrap;
}

/* Cards Grid */
.cards-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 25px;
  margin-bottom: 30px;
}

.flashcard {
  perspective: 1000px;
  cursor: pointer;
  height: 200px;
}

.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: var(--border-radius);
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  padding: 25px;
}

.flashcard-front {
  background: linear-gradient(135deg, var(--bg-card), #1e1e3f);
  border: 2px solid var(--neon-cyan);
  box-shadow: 0 0 20px rgba(0, 212, 255, 0.2);
}

.flashcard-back {
  background: linear-gradient(135deg, #1e1e3f, var(--bg-card));
  border: 2px solid var(--neon-pink);
  box-shadow: 0 0 20px rgba(255, 107, 157, 0.2);
  transform: rotateY(180deg);
}

.flashcard.learned .flashcard-front {
  border-color: var(--neon-green);
  box-shadow: 0 0 20px rgba(74, 222, 128, 0.3);
}

.flashcard.learned .flashcard-back {
  border-color: var(--neon-green);
}

.word-english {
  font-family: 'Orbitron', sans-serif;
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--neon-cyan);
  text-align: center;
}

.word-transcription {
  color: var(--text-secondary);
  font-size: 0.9rem;
  margin-top: 8px;
}

.word-hint {
  color: var(--neon-purple);
  font-size: 0.8rem;
  margin-top: 15px;
  opacity: 0.7;
}

.word-russian {
  font-size: 1.3rem;
  font-weight: 600;
  color: var(--neon-pink);
  text-align: center;
}

.word-example {
  color: var(--text-secondary);
  font-size: 0.85rem;
  margin-top: 12px;
  text-align: center;
  font-style: italic;
}

/* Card Navigation */
.card-navigation {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 20px;
}

.card-counter {
  font-weight: 600;
  color: var(--neon-purple);
}

/* Grammar */
.grammar-tabs {
  display: flex;
  gap: 10px;
  margin-bottom: 25px;
  flex-wrap: wrap;
}

.grammar-tab {
  background: var(--bg-card);
  border: 1px solid rgba(255, 255, 255, 0.1);
  color: var(--text-secondary);
  padding: 12px 20px;
  border-radius: 8px;
  cursor: pointer;
  transition: var(--transition);
}

.grammar-tab:hover {
  border-color: var(--neon-purple);
}

.grammar-tab.active {
  background: var(--neon-purple);
  border-color: var(--neon-purple);
  color: var(--bg-primary);
}

.grammar-content {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.grammar-block {
  background: var(--bg-card);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: var(--border-radius);
  padding: 20px;
}

.grammar-block h4 {
  color: var(--neon-cyan);
  margin-bottom: 12px;
  font-size: 1.1rem;
}

.grammar-block p {
  margin-bottom: 10px;
  line-height: 1.6;
}

.grammar-example {
  background: var(--bg-secondary);
  padding: 15px;
  border-radius: 8px;
  margin-top: 10px;
}

.grammar-example p {
  margin-bottom: 8px;
  font-size: 0.95rem;
}

.grammar-example p:last-child {
  margin-bottom: 0;
}

/* ===== LISTENING SECTION ===== */
.listening-tabs {
  display: flex;
  gap: 10px;
  margin-bottom: 30px;
  flex-wrap: wrap;
}

.listening-tab {
  background: var(--bg-card);
  border: 1px solid rgba(255, 255, 255, 0.1);
  color: var(--text-secondary);
  padding: 12px 20px;
  border-radius: 8px;
  cursor: pointer;
  transition: var(--transition);
  font-size: 0.95rem;
}

.listening-tab:hover {
  border-color: var(--neon-cyan);
  color: var(--neon-cyan);
}

.listening-tab.active {
  background: linear-gradient(135deg, var(--neon-cyan), var(--neon-purple));
  border-color: transparent;
  color: var(--bg-primary);
  font-weight: 600;
}

.listening-mode {
  animation: fadeIn 0.4s ease;
}

.audio-card {
  background: linear-gradient(135deg, var(--bg-card), #1e1e3f);
  border: 2px solid var(--neon-purple);
  border-radius: var(--border-radius);
  padding: 40px;
  text-align: center;
  margin-bottom: 25px;
  box-shadow: 0 0 30px rgba(192, 132, 252, 0.2);
}

.audio-icon {
  font-size: 4rem;
  margin-bottom: 15px;
  animation: pulse 2s infinite;
}

@keyframes pulse {
  0%, 100% { transform: scale(1); }
  50% { transform: scale(1.1); }
}

.audio-instruction {
  color: var(--text-secondary);
  font-size: 1.1rem;
  margin-bottom: 20px;
}

.btn-play {
  background: linear-gradient(135deg, var(--neon-cyan), var(--neon-purple));
  color: var(--bg-primary);
  padding: 15px 40px;
  font-size: 1.1rem;
  border-radius: 30px;
  border: none;
  cursor: pointer;
  transition: var(--transition);
  box-shadow: 0 4px 25px rgba(0, 212, 255, 0.4);
}

.btn-play:hover {
  transform: scale(1.05);
  box-shadow: 0 6px 35px rgba(0, 212, 255, 0.6);
}

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

.audio-status {
  margin-top: 15px;
  color: var(--neon-green);
  font-size: 0.9rem;
}

/* Audio Wave Animation */
.audio-wave {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 4px;
  height: 40px;
  margin-top: 20px;
}

.audio-wave span {
  width: 4px;
  height: 20px;
  background: var(--neon-cyan);
  border-radius: 2px;
  animation: wave 1s ease-in-out infinite;
}

.audio-wave span:nth-child(2) { animation-delay: 0.1s; }
.audio-wave span:nth-child(3) { animation-delay: 0.2s; }
.audio-wave span:nth-child(4) { animation-delay: 0.3s; }
.audio-wave span:nth-child(5) { animation-delay: 0.4s; }
.audio-wave span:nth-child(6) { animation-delay: 0.5s; }
.audio-wave span:nth-child(7) { animation-delay: 0.6s; }
.audio-wave span:nth-child(8) { animation-delay: 0.7s; }
.audio-wave span:nth-child(9) { animation-delay: 0.8s; }
.audio-wave span:nth-child(10) { animation-delay: 0.9s; }

.audio-wave.active span {
  animation: wave 0.5s ease-in-out infinite;
}

@keyframes wave {
  0%, 100% { height: 10px; opacity: 0.5; }
  50% { height: 35px; opacity: 1; }
}

/* Audio Options */
.audio-options {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 15px;
  margin-bottom: 20px;
}

.audio-option {
  background: var(--bg-secondary);
  border: 2px solid rgba(255, 255, 255, 0.1);
  color: var(--text-primary);
  padding: 20px;
  border-radius: 10px;
  cursor: pointer;
  font-size: 1rem;
  transition: var(--transition);
  text-align: center;
}

.audio-option:hover {
  border-color: var(--neon-cyan);
  transform: translateY(-3px);
}

.audio-option.correct {
  background: rgba(74, 222, 128, 0.2);
  border-color: var(--neon-green);
  color: var(--neon-green);
  animation: correctPulse 0.5s ease;
}

.audio-option.wrong {
  background: rgba(248, 113, 113, 0.2);
  border-color: var(--neon-red);
  color: var(--neon-red);
  animation: shake 0.5s ease;
}

@keyframes correctPulse {
  0% { transform: scale(1); }
  50% { transform: scale(1.05); }
  100% { transform: scale(1); }
}

@keyframes shake {
  0%, 100% { transform: translateX(0); }
  25% { transform: translateX(-10px); }
  75% { transform: translateX(10px); }
}

.audio-result {
  text-align: center;
  padding: 15px;
  border-radius: 10px;
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: 20px;
}

.audio-result.correct {
  background: rgba(74, 222, 128, 0.1);
  color: var(--neon-green);
  border: 1px solid var(--neon-green);
}

.audio-result.wrong {
  background: rgba(248, 113, 113, 0.1);
  color: var(--neon-red);
  border: 1px solid var(--neon-red);
}

/* Dialog Card */
.dialog-card {
  border-color: var(--neon-pink);
  box-shadow: 0 0 30px rgba(255, 107, 157, 0.2);
}

.dialog-text {
  background: var(--bg-secondary);
  border-radius: 10px;
  padding: 20px;
  margin-top: 20px;
  font-style: italic;
  color: var(--text-secondary);
  text-align: left;
  line-height: 1.8;
  max-height: 200px;
  overflow-y: auto;
}

.dialog-text .speaker {
  color: var(--neon-cyan);
  font-weight: 600;
  margin-right: 8px;
}

/* Dictation */
.dictation-controls {
  display: flex;
  gap: 10px;
  justify-content: center;
  margin-bottom: 15px;
}

.dictation-input-container {
  display: flex;
  gap: 10px;
  margin-bottom: 20px;
}

.dictation-input {
  flex: 1;
  background: var(--bg-secondary);
  border: 2px solid rgba(255, 255, 255, 0.1);
  color: var(--text-primary);
  padding: 15px 20px;
  border-radius: 10px;
  font-size: 1rem;
  font-family: 'Inter', sans-serif;
  transition: var(--transition);
}

.dictation-input:focus {
  outline: none;
  border-color: var(--neon-cyan);
  box-shadow: 0 0 15px rgba(0, 212, 255, 0.2);
}

.dictation-input::placeholder {
  color: var(--text-secondary);
}

.replay-count {
  color: var(--neon-yellow);
  font-size: 0.9rem;
}

.dictation-correct-text {
  background: rgba(74, 222, 128, 0.1);
  border: 1px solid var(--neon-green);
  border-radius: 10px;
  padding: 15px;
  margin-top: 15px;
  text-align: center;
}

.dictation-correct-text span {
  color: var(--neon-green);
}

/* Listening Stats */
.listening-stats {
  display: flex;
  justify-content: center;
  gap: 30px;
  margin-top: 30px;
  padding: 20px;
  background: var(--bg-card);
  border-radius: var(--border-radius);
  color: var(--text-secondary);
}

.listening-stats strong {
  color: var(--neon-cyan);
}

/* Quiz */
.quiz-container {
  max-width: 700px;
  margin: 0 auto;
}

.quiz-start {
  text-align: center;
  padding: 50px;
  background: var(--bg-card);
  border-radius: var(--border-radius);
}

.quiz-start h3 {
  font-family: 'Orbitron', sans-serif;
  font-size: 1.8rem;
  color: var(--neon-purple);
  margin-bottom: 15px;
}

.quiz-start p {
  color: var(--text-secondary);
  margin-bottom: 25px;
}

.quiz-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 25px;
  padding-bottom: 15px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.quiz-question-num {
  color: var(--text-secondary);
  font-size: 0.9rem;
}

.quiz-score {
  color: var(--neon-green);
  font-weight: 600;
}

.quiz-question {
  font-size: 1.2rem;
  color: var(--text-primary);
  margin-bottom: 25px;
  line-height: 1.6;
}

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

.quiz-option {
  background: var(--bg-secondary);
  border: 2px solid rgba(255, 255, 255, 0.1);
  color: var(--text-primary);
  padding: 15px 20px;
  border-radius: 10px;
  cursor: pointer;
  font-size: 1rem;
  text-align: left;
  transition: var(--transition);
}

.quiz-option:hover {
  border-color: var(--neon-cyan);
  transform: translateX(5px);
}

.quiz-option.correct {
  background: rgba(74, 222, 128, 0.2);
  border-color: var(--neon-green);
  color: var(--neon-green);
}

.quiz-option.wrong {
  background: rgba(248, 113, 113, 0.2);
  border-color: var(--neon-red);
  color: var(--neon-red);
}

.quiz-result {
  margin-top: 20px;
  font-size: 1.1rem;
  font-weight: 600;
  text-align: center;
}

.quiz-finish h3 {
  font-size: 1.8rem;
  color: var(--neon-purple);
  margin-bottom: 20px;
}

.quiz-score-big {
  font-family: 'Orbitron', sans-serif;
  font-size: 4rem;
  font-weight: 900;
  background: linear-gradient(135deg, var(--neon-cyan), var(--neon-pink));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: 20px;
}

.quiz-message {
  font-size: 1.2rem;
  color: var(--text-secondary);
  margin-bottom: 30px;
}

/* Stats */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 20px;
  margin-bottom: 20px;
}

.stat-card {
  background: var(--bg-card);
  border: 1px solid rgba(0, 212, 255, 0.15);
  border-radius: var(--border-radius);
  padding: 25px;
  text-align: center;
  transition: var(--transition);
}

.stat-card:hover {
  transform: translateY(-5px);
  border-color: var(--neon-purple);
  box-shadow: 0 10px 30px rgba(192, 132, 252, 0.2);
}

.stat-icon {
  font-size: 2.5rem;
  margin-bottom: 10px;
}

.stat-value {
  font-family: 'Orbitron', sans-serif;
  font-size: 2rem;
  font-weight: 700;
  color: var(--neon-cyan);
  margin-bottom: 5px;
}

.stat-label {
  color: var(--text-secondary);
  font-size: 0.9rem;
}

/* Footer */
.footer {
  background: var(--bg-secondary);
  border-top: 1px solid rgba(255, 255, 255, 0.05);
  padding: 20px 0;
  text-align: center;
  color: var(--text-secondary);
  font-size: 0.9rem;
}

.footer p {
  margin: 0;
}

/* Responsive */
@media (max-width: 768px) {
  .header .container {
    flex-direction: column;
    gap: 15px;
  }
  
  .logo {
    font-size: 1.3rem;
  }
  
  .nav {
    width: 100%;
    justify-content: center;
  }
  
  .section-title {
    font-size: 1.5rem;
  }
  
  .cards-grid {
    grid-template-columns: 1fr;
  }
  
  .stats-grid {
    grid-template-columns: 1fr 1fr;
  }
  
  .quiz-score-big {
    font-size: 3rem;
  }
  
  .grammar-tabs {
    justify-content: center;
  }

  .audio-options {
    grid-template-columns: 1fr;
  }

  .dictation-input-container {
    flex-direction: column;
  }

  .listening-stats {
    flex-direction: column;
    gap: 15px;
    text-align: center;
  }
}

@media (max-width: 480px) {
  .nav-btn {
    padding: 8px 12px;
    font-size: 0.8rem;
  }
  
  .cards-controls {
    flex-direction: column;
  }
  
  .card-navigation {
    flex-wrap: wrap;
  }
  
  .stats-grid {
    grid-template-columns: 1fr;
  }

  .audio-card {
    padding: 25px;
  }

  .listening-tabs {
    justify-content: center;
  }
}