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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
}

.container {
  background: white;
  border-radius: 20px;
  box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
  max-width: 600px;
  width: 100%;
  padding: 40px;
}

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

.logo {
  max-width: 200px;
  height: auto;
  margin-bottom: 20px;
}

h1 {
  color: #333;
  font-size: 32px;
  margin-bottom: 10px;
}

header p {
  color: #666;
  font-size: 16px;
}

.drop-zone {
  border: 3px dashed #667eea;
  border-radius: 15px;
  padding: 60px 20px;
  text-align: center;
  cursor: pointer;
  transition: all 0.3s ease;
  background: #f8f9ff;
}

.drop-zone:hover {
  border-color: #764ba2;
  background: #f0f2ff;
  transform: translateY(-2px);
}

.drop-zone.drag-over {
  border-color: #764ba2;
  background: #e8ebff;
  transform: scale(1.02);
}

.upload-icon {
  width: 64px;
  height: 64px;
  color: #667eea;
  margin-bottom: 20px;
}

.drop-text {
  font-size: 20px;
  color: #333;
  margin-bottom: 8px;
  font-weight: 600;
}

.drop-subtext {
  font-size: 14px;
  color: #666;
  margin-bottom: 20px;
}

.file-types {
  font-size: 12px;
  color: #999;
  margin-top: 10px;
}

.progress {
  text-align: center;
  padding: 40px 20px;
}

.spinner {
  border: 4px solid #f3f3f3;
  border-top: 4px solid #667eea;
  border-radius: 50%;
  width: 50px;
  height: 50px;
  animation: spin 1s linear infinite;
  margin: 0 auto 20px;
}

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

#progress-text {
  color: #667eea;
  font-size: 16px;
  font-weight: 600;
}

.error {
  background: #fee;
  border: 1px solid #fcc;
  border-radius: 10px;
  padding: 20px;
  text-align: center;
}

#error-text {
  color: #c33;
  font-size: 14px;
}

.hidden {
  display: none;
}

footer {
  margin-top: 40px;
  text-align: center;
  padding-top: 20px;
  border-top: 1px solid #eee;
}

footer p {
  color: #999;
  font-size: 12px;
}

.results {
  text-align: center;
  padding: 20px;
}

.results h3 {
  color: #333;
  font-size: 24px;
  margin-bottom: 20px;
}

#file-list {
  margin-bottom: 20px;
}

.file-item {
  background: #f8f9ff;
  border-radius: 10px;
  padding: 15px 20px;
  margin-bottom: 10px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.file-name {
  color: #333;
  font-size: 14px;
  font-weight: 500;
}

.download-btn {
  background: #667eea;
  color: white;
  border: none;
  padding: 8px 16px;
  border-radius: 6px;
  cursor: pointer;
  font-size: 14px;
  transition: background 0.3s ease;
}

.download-btn:hover {
  background: #764ba2;
}

.button-group {
  display: flex;
  gap: 15px;
  justify-content: center;
  flex-wrap: wrap;
}

.download-all-btn, .convert-more-btn {
  border: none;
  padding: 12px 32px;
  border-radius: 10px;
  cursor: pointer;
  font-size: 16px;
  font-weight: 600;
  transition: transform 0.3s ease;
}

.download-all-btn {
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: white;
  box-shadow: 0 4px 15px rgba(102, 126, 234, 0.4);
}

.download-all-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(102, 126, 234, 0.6);
}

.convert-more-btn {
  background: white;
  color: #667eea;
  border: 2px solid #667eea;
  box-shadow: 0 4px 15px rgba(102, 126, 234, 0.2);
}

.convert-more-btn:hover {
  transform: translateY(-2px);
  background: #f8f9ff;
  box-shadow: 0 6px 20px rgba(102, 126, 234, 0.4);
}