* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
}

:root {
  --sky-blue: #00c4ff;
  --sky-pink: #ff005e;
  --sky-green: #00ffb3;
  --sky-blue-light: rgba(0, 196, 255, 0.1);
  --sky-pink-light: rgba(255, 0, 94, 0.1);
  --sky-green-light: rgba(0, 255, 179, 0.1);
  --light-bg: #ffffff;
  --card-bg: #f8f9fa;
  --card-hover: #f1f3f4;
  --text-primary: #202124;
  --text-secondary: #5f6368;
  --text-tertiary: #9aa0a6;
  --border-light: #dadce0;
  --shadow: 0 2px 10px rgba(0, 0, 0, 0.08);
  --shadow-hover: 0 8px 25px rgba(0, 0, 0, 0.12);
}

body {
  background: var(--light-bg);
  color: var(--text-primary);
  line-height: 1;
  padding: 10px;
}

.container {
  max-width: 1000px;
  margin: 0 auto;
  padding: 70px;
}

/* Hero Section */
.hero-section {
  text-align: center;
  margin-bottom: 20px;
  padding: 10px 0;
}

.hero-section h1 {
  font-size: 1.5rem;
  margin-bottom: 10px;
  background: linear-gradient(90deg, var(--sky-blue), var(--sky-pink), var(--sky-green));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  font-weight: 700;
  letter-spacing: -0.5px;
}

.hero-section p {
  font-size: 1rem;
  color: var(--text-secondary);
  max-width: 800px;
  margin: 0 auto;
}

.gradient-bar {
  height: 3px;
  width: 300px;
  background: linear-gradient(90deg, var(--sky-blue), var(--sky-pink), var(--sky-green));
  margin: 10px auto 15px;
  border-radius: 2px;
}

/* Upload Section */
.upload-section {
  margin: 30px 0;
  text-align: center;
}

.upload-box {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  background: var(--card-bg);
  border: 2px dashed var(--sky-green);
  border-radius: 12px;
  padding: 40px 20px;
  cursor: pointer;
  transition: all 0.3s ease;
  min-height: 200px;
  box-shadow: var(--shadow);
  position: relative;
  overflow: hidden;
}

.upload-box::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 3px;
  background: linear-gradient(90deg, var(--sky-blue), var(--sky-pink), var(--sky-green));
}

.upload-box:hover {
  background: var(--sky-green-light);
  box-shadow: var(--shadow-hover);
  transform: translateY(-3px);
}

.upload-icon {
  font-size: 48px;
  margin-bottom: 15px;
  color: var(--sky-green);
  transition: all 0.3s ease;
}

.upload-box:hover .upload-icon {
  color: var(--sky-pink);
  transform: scale(1.1);
}

.upload-content p {
  margin: 5px 0;
  font-size: 1.1rem;
}

.upload-content strong {
  color: var(--text-primary);
}

.upload-content small {
  color: var(--text-tertiary);
  font-size: 0.9rem;
}

#audioFile {
  display: none;
}

/* Upload Button Style */
.upload-button {
  display: inline-block;
  margin-top: 15px;
  padding: 12px 30px;
  background: linear-gradient(90deg, var(--sky-green), var(--sky-blue));
  color: white;
  border: none;
  border-radius: 6px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s ease;
  box-shadow: var(--shadow);
  position: relative;
  overflow: hidden;
  z-index: 1;
}

.upload-button::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, var(--sky-blue), var(--sky-pink), var(--sky-green));
  transition: left 0.5s ease;
  z-index: -1;
}

.upload-button:hover::before {
  left: 0;
}

.upload-button:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-hover);
}

/* Player Section */
.player-section {
  margin: 40px 0;
}

.player-container {
  background: var(--card-bg);
  padding: 30px;
  border-radius: 12px;
  border: 1px solid var(--border-light);
  box-shadow: var(--shadow);
}

.audio-player {
  max-width: 600px;
  margin: 0 auto;
}

.audio-info {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 20px;
}

.audio-info h3 {
  color: var(--text-primary);
  font-size: 1.2rem;
}

.audio-duration {
  color: var(--text-secondary);
  font-weight: 600;
}

.audio-controls {
  display: flex;
  justify-content: center;
  gap: 15px;
  margin-bottom: 20px;
}

.control-btn {
  width: 50px;
  height: 50px;
  border-radius: 50%;
  border: none;
  background: var(--sky-green);
  color: white;
  font-size: 1.2rem;
  cursor: pointer;
  transition: all 0.3s ease;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--shadow);
}

.control-btn:hover {
  background: var(--sky-blue);
  transform: scale(1.05);
  box-shadow: var(--shadow-hover);
}

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

.progress-container {
  margin-top: 15px;
}

.progress-bar {
  width: 100%;
  height: 8px;
  background: var(--border-light);
  border-radius: 4px;
  overflow: hidden;
  margin-bottom: 10px;
}

.progress {
  height: 100%;
  background: linear-gradient(90deg, var(--sky-green), var(--sky-blue));
  border-radius: 4px;
  width: 0%;
  transition: width 0.1s linear;
}

.time-display {
  display: flex;
  justify-content: space-between;
  color: var(--text-secondary);
  font-size: 0.9rem;
}

/* Pitch Section */
.pitch-section {
  margin: 40px 0;
}

.pitch-controls {
  background: var(--card-bg);
  padding: 30px;
  border-radius: 12px;
  border: 1px solid var(--border-light);
  box-shadow: var(--shadow);
}

.pitch-slider-container {
  margin-bottom: 25px;
}

.pitch-label {
  display: block;
  margin-bottom: 15px;
  font-weight: 600;
  color: var(--text-primary);
  font-size: 1.1rem;
}

.pitch-label i {
  margin-right: 8px;
  color: var(--sky-green);
}

.pitch-slider {
  width: 100%;
  height: 8px;
  border-radius: 4px;
  background: var(--border-light);
  outline: none;
  -webkit-appearance: none;
}

.pitch-slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 20px;
  height: 20px;
  border-radius: 50%;
  background: var(--sky-green);
  cursor: pointer;
  box-shadow: var(--shadow);
}

.pitch-slider::-moz-range-thumb {
  width: 20px;
  height: 20px;
  border-radius: 50%;
  background: var(--sky-green);
  cursor: pointer;
  border: none;
  box-shadow: var(--shadow);
}

.pitch-markers {
  display: flex;
  justify-content: space-between;
  margin-top: 10px;
  color: var(--text-secondary);
  font-size: 0.8rem;
}

.pitch-description {
  text-align: center;
  margin-top: 10px;
  color: var(--text-tertiary);
  font-size: 0.85rem;
}

/* Preset Section */
.preset-section {
  margin: 30px 0;
  padding: 20px 0;
  border-top: 1px solid var(--border-light);
  border-bottom: 1px solid var(--border-light);
}

.preset-section h3 {
  margin-bottom: 15px;
  color: var(--text-primary);
  font-size: 1.1rem;
}

.preset-section h3 i {
  margin-right: 8px;
  color: var(--sky-blue);
}

.preset-buttons {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  justify-content: center;
}

.preset-btn {
  padding: 10px 15px;
  border: 2px solid var(--sky-blue);
  background: transparent;
  color: var(--sky-blue);
  border-radius: 6px;
  cursor: pointer;
  font-weight: 600;
  transition: all 0.3s ease;
  font-size: 0.9rem;
}

.preset-btn:hover {
  background: var(--sky-blue-light);
  transform: translateY(-2px);
}

.preset-btn.active {
  background: var(--sky-blue);
  color: white;
}

/* Key Section */
.key-section {
  margin: 25px 0;
}

.key-section h3 {
  margin-bottom: 15px;
  color: var(--text-primary);
  font-size: 1.1rem;
}

.key-section h3 i {
  margin-right: 8px;
  color: var(--sky-pink);
}

.key-controls {
  display: flex;
  align-items: center;
  gap: 20px;
  flex-wrap: wrap;
}

.key-selector {
  display: flex;
  align-items: center;
  gap: 10px;
}

.key-selector label {
  font-weight: 600;
  color: var(--text-primary);
}

.key-dropdown {
  padding: 8px 12px;
  border: 2px solid var(--border-light);
  border-radius: 6px;
  background: var(--light-bg);
  color: var(--text-primary);
  font-size: 0.9rem;
  cursor: pointer;
  transition: all 0.3s ease;
}

.key-dropdown:hover {
  border-color: var(--sky-blue);
}

.key-dropdown:focus {
  outline: none;
  border-color: var(--sky-green);
}

.key-preview {
  padding: 8px 15px;
  background: var(--sky-green-light);
  border-radius: 6px;
  font-weight: 600;
  color: var(--sky-green);
}

/* Advanced Options */
.advanced-options {
  margin-top: 25px;
  padding-top: 20px;
  border-top: 1px solid var(--border-light);
}

.advanced-options h3 {
  margin-bottom: 15px;
  color: var(--text-primary);
  font-size: 1.1rem;
}

.advanced-options h3 i {
  margin-right: 8px;
  color: var(--text-secondary);
}

.option-checkbox {
  margin: 12px 0;
}

.option-checkbox label {
  display: flex;
  align-items: center;
  cursor: pointer;
  font-weight: 500;
  color: var(--text-primary);
  padding: 8px 12px;
  border-radius: 6px;
  transition: all 0.3s ease;
}

.option-checkbox label:hover {
  background: var(--sky-blue-light);
}

.option-checkbox input {
  margin-right: 12px;
  transform: scale(1.2);
}

/* Buttons Section */
.buttons-section {
  text-align: center;
  margin: 40px 0;
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 15px;
  flex-wrap: wrap;
}

.action-button {
  padding: 15px 40px;
  border: none;
  background: linear-gradient(90deg, var(--sky-green), var(--sky-blue));
  color: white;
  border-radius: 6px;
  cursor: pointer;
  transition: all 0.3s ease;
  font-weight: 600;
  font-size: 1.1rem;
  box-shadow: var(--shadow);
  position: relative;
  overflow: hidden;
  z-index: 1;
}

.action-button::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, var(--sky-blue), var(--sky-pink), var(--sky-green));
  transition: left 0.5s ease;
  z-index: -1;
}

.action-button:hover::before {
  left: 0;
}

.action-button:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-hover);
}

.reset-button {
  padding: 15px 40px;
  border: 2px solid var(--sky-pink);
  background: transparent;
  color: var(--sky-pink);
  border-radius: 6px;
  cursor: pointer;
  transition: all 0.3s ease;
  font-weight: 600;
  font-size: 1.1rem;
  box-shadow: var(--shadow);
  position: relative;
  overflow: hidden;
  z-index: 1;
  margin-left: 15px;
}

.reset-button::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: var(--sky-pink);
  transition: left 0.5s ease;
  z-index: -1;
}

.reset-button:hover::before {
  left: 0;
}

.reset-button:hover {
  color: white;
  transform: translateY(-3px);
  box-shadow: var(--shadow-hover);
}

/* Results Section */
.results-section {
  margin: 40px 0;
}

.results-container {
  background: var(--light-bg);
  border-radius: 12px;
  border: 1px solid var(--border-light);
  box-shadow: var(--shadow);
  overflow: hidden;
}

.results-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 20px;
  background: var(--card-bg);
  border-bottom: 1px solid var(--border-light);
  font-weight: 600;
  color: var(--text-primary);
}

.results-actions {
  display: flex;
  gap: 10px;
}

.action-btn {
  padding: 8px 15px;
  border: 1px solid var(--sky-blue);
  background: transparent;
  color: var(--sky-blue);
  border-radius: 4px;
  cursor: pointer;
  font-size: 0.9rem;
  transition: all 0.3s ease;
}

.action-btn:hover {
  background: var(--sky-blue);
  color: white;
}

.results-content {
  padding: 25px;
}

/* Pitch Comparison */
.pitch-comparison {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 30px;
  margin-bottom: 25px;
  padding: 20px;
  background: var(--sky-green-light);
  border-radius: 10px;
}

.comparison-item {
  text-align: center;
  flex: 1;
}

.comparison-item h4 {
  margin-bottom: 10px;
  color: var(--text-primary);
  font-size: 1.1rem;
}

.audio-info-small {
  display: flex;
  flex-direction: column;
  gap: 5px;
  font-size: 0.9rem;
  color: var(--text-secondary);
}

.comparison-arrow {
  font-size: 1.5rem;
  color: var(--sky-pink);
}

.processed-player {
  max-width: 600px;
  margin: 0 auto;
}

.results-stats {
  display: flex;
  justify-content: space-around;
  padding: 15px 20px;
  background: var(--card-bg);
  border-top: 1px solid var(--border-light);
  font-weight: 600;
  color: var(--text-primary);
  flex-wrap: wrap;
  gap: 15px;
}

/* Use Cases Section */
.use-cases-section {
  margin: 50px 0;
}

.use-cases-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 20px;
}

.use-case-card {
  background: var(--light-bg);
  padding: 25px 20px;
  border-radius: 12px;
  text-align: center;
  transition: all 0.3s ease;
  border: 1px solid var(--border-light);
  box-shadow: var(--shadow);
  position: relative;
  overflow: hidden;
}

.use-case-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 3px;
  background: linear-gradient(90deg, var(--sky-blue), var(--sky-pink), var(--sky-green));
}

.use-case-card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-hover);
}

.use-case-icon {
  font-size: 2.5rem;
  margin-bottom: 15px;
  color: var(--sky-green);
  height: 60px;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.3s ease;
}

.use-case-card:hover .use-case-icon {
  color: var(--sky-pink);
  transform: scale(1.05);
}

.use-case-card h3 {
  margin-bottom: 12px;
  color: var(--text-primary);
  font-size: 1.2rem;
  font-weight: 600;
}

.use-case-card p {
  color: var(--text-secondary);
  font-size: 0.9rem;
  line-height: 1.4;
}

/* Steps Section */
.steps-section {
  margin: 50px 0;
}

.steps-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 20px;
}

.step-card {
  background: var(--light-bg);
  padding: 25px 20px;
  border-radius: 12px;
  text-align: center;
  transition: all 0.3s ease;
  border: 1px solid var(--border-light);
  box-shadow: var(--shadow);
  position: relative;
  overflow: hidden;
}

.step-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 3px;
  background: linear-gradient(90deg, var(--sky-blue), var(--sky-pink), var(--sky-green));
}

.step-card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-hover);
}

.step-icon {
  font-size: 2.5rem;
  margin-bottom: 15px;
  color: var(--sky-green);
  height: 60px;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.3s ease;
}

.step-card:hover .step-icon {
  color: var(--sky-pink);
  transform: scale(1.05);
}

.step-card h3 {
  margin-bottom: 12px;
  color: var(--text-primary);
  font-size: 1.2rem;
  font-weight: 600;
}

.step-card p {
  color: var(--text-secondary);
  font-size: 0.9rem;
  line-height: 1.4;
}

/* FAQ Section */
.faq-section {
  margin: 50px 0;
}

.faq-container {
  max-width: 800px;
  margin: 0 auto;
}

.faq-item {
  background: var(--light-bg);
  margin-bottom: 12px;
  border-radius: 10px;
  overflow: hidden;
  border: 1px solid var(--border-light);
  box-shadow: var(--shadow);
  transition: all 0.3s ease;
}

.faq-item:hover {
  background: var(--card-hover);
}

.faq-question {
  padding: 18px 20px;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 1rem;
  font-weight: 500;
  color: var(--text-primary);
  transition: all 0.3s ease;
}

.faq-question:hover {
  color: var(--sky-green);
}

.faq-question i {
  transition: transform 0.3s ease;
  color: var(--sky-pink);
}

.faq-answer {
  padding: 0 20px;
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.4s ease, padding 0.4s ease;
  color: var(--text-secondary);
  line-height: 1.5;
  font-size: 0.9rem;
}

.faq-item.active .faq-answer {
  padding: 0 20px 18px;
  max-height: 500px;
}

.faq-item.active .faq-question i {
  transform: rotate(45deg);
}

/* Animation for page load */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.fade-in {
  animation: fadeInUp 0.5s ease forwards;
}

/* Section Title */
.section-title {
  font-size: 1.8rem;
  text-align: center;
  margin: 40px 0 30px;
  position: relative;
  color: var(--text-primary);
  font-weight: 600;
}

.section-title::after {
  content: '';
  display: block;
  width: 80px;
  height: 4px;
  background: linear-gradient(90deg, var(--sky-blue), var(--sky-pink), var(--sky-green));
  margin: 15px auto 0;
  border-radius: 2px;
}

/* Responsive Design */
@media (max-width: 768px) {
  .container {
    padding: 0 10px;
  }
  
  .hero-section h1 {
    font-size: 1.7rem;
  }
  
  .section-title {
    font-size: 1.5rem;
    margin: 30px 0 20px;
  }
  
  .use-cases-grid,
  .steps-grid {
    grid-template-columns: 1fr;
    gap: 15px;
  }
  
  .upload-box {
    padding: 30px 15px;
    min-height: 180px;
  }
  
  .upload-icon {
    font-size: 40px;
  }
  
  .action-button, .reset-button {
    width: 100%;
    padding: 15px;
  }
  
  .player-container, .pitch-controls {
    padding: 20px 15px;
  }
  
  .preset-buttons {
    gap: 5px;
  }
  
  .preset-btn {
    padding: 8px 12px;
    font-size: 0.8rem;
  }
  
  .key-controls {
    flex-direction: column;
    align-items: stretch;
    gap: 15px;
  }
  
  .key-selector {
    justify-content: space-between;
  }
  
  .pitch-comparison {
    flex-direction: column;
    gap: 15px;
    text-align: center;
  }
  
  .comparison-arrow {
    transform: rotate(90deg);
  }
  
  .results-header {
    flex-direction: column;
    gap: 15px;
    text-align: center;
  }
  
  .results-actions {
    width: 100%;
    justify-content: center;
  }
  
  .results-stats {
    flex-direction: column;
    gap: 10px;
    text-align: center;
  }
}

@media (max-width: 480px) {
  .hero-section h1 {
    font-size: 1.5rem;
  }
  
  .hero-section p {
    font-size: 1rem;
  }
  
  .section-title {
    font-size: 1.3rem;
  }
  
  .step-card, .use-case-card {
    padding: 20px 15px;
  }
  
  .audio-controls {
    gap: 10px;
  }
  
  .control-btn {
    width: 45px;
    height: 45px;
  }
  
  .reset-button {
    margin-left: 0;
  }
  
  .preset-buttons {
    flex-direction: column;
  }
  
  .preset-btn {
    width: 100%;
  }
}