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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  min-height: 100vh;
  padding: 20px;
}

.container {
  max-width: 600px;
  margin: 0 auto;
  background: white;
  border-radius: 16px;
  padding: 32px;
  box-shadow: 0 10px 40px rgba(0, 0, 0, 0.2);
}

h1 {
  text-align: center;
  color: #333;
  margin-bottom: 24px;
  font-size: 1.8rem;
}

.form-group {
  margin-bottom: 16px;
}

label {
  display: block;
  margin-bottom: 6px;
  color: #555;
  font-weight: 500;
  font-size: 0.9rem;
}

textarea,
input[type="text"],
input[type="password"] {
  width: 100%;
  padding: 12px;
  border: 2px solid #e0e0e0;
  border-radius: 8px;
  font-size: 1rem;
  resize: vertical;
  transition: border-color 0.2s;
}

textarea:focus,
input[type="text"]:focus,
input[type="password"]:focus {
  outline: none;
  border-color: #667eea;
}

/* APIキー入力欄 */
.api-key-input-wrapper {
  position: relative;
  display: flex;
  align-items: center;
}

.api-key-input-wrapper input {
  padding-right: 44px;
  resize: none;
}

.toggle-visibility-btn {
  position: absolute;
  right: 8px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #888;
  transition: color 0.2s;
}

.toggle-visibility-btn:hover {
  color: #667eea;
}

select,
input[type="range"] {
  width: 100%;
  padding: 8px;
  border: 2px solid #e0e0e0;
  border-radius: 8px;
  font-size: 0.9rem;
}

select:focus {
  outline: none;
  border-color: #667eea;
}

input[type="range"] {
  padding: 0;
  height: 8px;
  -webkit-appearance: none;
  background: #e0e0e0;
  border: none;
  cursor: pointer;
}

input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 20px;
  height: 20px;
  background: #667eea;
  border-radius: 50%;
  cursor: pointer;
}

input[type="range"]::-moz-range-thumb {
  width: 20px;
  height: 20px;
  background: #667eea;
  border-radius: 50%;
  cursor: pointer;
  border: none;
}

.advanced-settings {
  margin-bottom: 20px;
  border: 1px solid #e0e0e0;
  border-radius: 8px;
  padding: 12px;
}

.advanced-settings summary {
  cursor: pointer;
  font-weight: 500;
  color: #667eea;
  padding: 4px;
}

.advanced-settings[open] summary {
  margin-bottom: 16px;
}

.settings-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 16px;
}

.generate-btn {
  width: 100%;
  padding: 14px 24px;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: white;
  border: none;
  border-radius: 8px;
  font-size: 1.1rem;
  font-weight: 600;
  cursor: pointer;
  transition: transform 0.2s, box-shadow 0.2s;
}

.generate-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(102, 126, 234, 0.4);
}

.generate-btn:active {
  transform: translateY(0);
}

.generate-btn:disabled {
  opacity: 0.6;
  cursor: not-allowed;
  transform: none;
}

.loading {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
  padding: 20px;
  color: #667eea;
}

.spinner {
  width: 24px;
  height: 24px;
  border: 3px solid #e0e0e0;
  border-top-color: #667eea;
  border-radius: 50%;
  animation: spin 1s linear infinite;
}

@keyframes spin {
  to {
    transform: rotate(360deg);
  }
}

.error {
  background: #fee;
  border: 1px solid #fcc;
  color: #c00;
  padding: 12px;
  border-radius: 8px;
  margin-top: 16px;
}

.warning-text {
  color: #e67e22;
  font-size: 0.75rem;
  font-weight: normal;
}

.audio-container {
  margin-top: 24px;
  padding: 20px;
  background: #f8f9fa;
  border-radius: 8px;
}

audio {
  width: 100%;
  margin-bottom: 12px;
}

.download-btn {
  display: inline-block;
  padding: 10px 20px;
  background: #28a745;
  color: white;
  text-decoration: none;
  border-radius: 6px;
  font-weight: 500;
  transition: background 0.2s;
}

.download-btn:hover {
  background: #218838;
}

.hidden {
  display: none !important;
}

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

  h1 {
    font-size: 1.4rem;
  }

  .settings-grid {
    grid-template-columns: 1fr;
  }
}