:root {
  --bg-color: #f8fafc;
  --card-bg: #ffffff;
  --text-main: #0f172a;
  --text-muted: #475569;
  --border-color: #cbd5e1;
  --primary-color: #2563eb;
  --primary-hover: #1d4ed8;
  --primary-disabled: #94a3b8;
  --accent-green: #166534;
  --accent-green-bg: #f0fdf4;
  --error-color: #b91c1c;
  --error-bg: #fef2f2;
  --error-border: #fecaca;
  --focus-ring: #3b82f6;
  --radius: 10px;
}

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

body {
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  background-color: var(--bg-color);
  color: var(--text-main);
  line-height: 1.5;
  padding: 24px 16px;
}

.app-container {
  max-width: 960px;
  margin: 0 auto;
}

.app-header {
  text-align: center;
  margin-bottom: 24px;
}

.app-header h1 {
  font-size: 2rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 8px;
}

.subtitle {
  color: var(--text-muted);
  font-size: 0.95rem;
  margin-bottom: 12px;
}

.privacy-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.85rem;
  color: var(--accent-green);
  background-color: var(--accent-green-bg);
  padding: 4px 12px;
  border-radius: 9999px;
  border: 1px solid #bbf7d0;
}

/* クイックサンプルバー */
.quick-samples {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  background: var(--card-bg);
  padding: 12px 16px;
  border-radius: var(--radius);
  border: 1px solid var(--border-color);
  margin-bottom: 20px;
}

.quick-samples-label {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--text-muted);
}

.sample-btn {
  background: #f1f5f9;
  border: 1px solid var(--border-color);
  color: var(--text-main);
  font-size: 0.8125rem;
  padding: 6px 12px;
  border-radius: 6px;
  cursor: pointer;
  transition: background 0.15s ease, border-color 0.15s ease;
}

.sample-btn:hover {
  background: #e2e8f0;
  border-color: #94a3b8;
}

.sample-btn.error-test-btn {
  color: var(--error-color);
  border-color: #fca5a5;
  background: #fff5f5;
}

.sample-btn.error-test-btn:hover {
  background: #fee2e2;
}

/* 3スロットグリッド */
.image-slots-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 16px;
  margin-bottom: 24px;
}

.image-slot {
  background: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: var(--radius);
  padding: 16px;
  display: flex;
  flex-direction: column;
}

.slot-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 10px;
}

.slot-label {
  font-weight: 600;
  font-size: 0.95rem;
}

.slot-status {
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--text-muted);
}

.preview-card {
  position: relative;
  width: 100%;
  aspect-ratio: 1 / 1;
  background: #f1f5f9;
  /* WCAG 1.4.11: 操作領域を識別する枠は非テキスト 3:1 以上（#64748b は背景比 約4.3:1） */
  border: 2px dashed #64748b;
  border-radius: 8px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  overflow: hidden;
  cursor: pointer;
  transition: border-color 0.15s ease, background 0.15s ease;
}

.preview-card:hover, .preview-card.drag-over {
  border-color: var(--primary-color);
  background: #eff6ff;
}

.file-input {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  opacity: 0;
  cursor: pointer;
  z-index: 2;
}

.preview-content {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  padding: 12px;
  color: var(--text-muted);
  pointer-events: none;
}

.upload-icon {
  margin-bottom: 8px;
  color: var(--text-muted);
}

.upload-hint {
  font-size: 0.8125rem;
  line-height: 1.4;
}

.preview-img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  position: absolute;
  inset: 0;
  z-index: 1;
}

/* アクションボタンとメッセージ */
.action-section {
  text-align: center;
  margin-bottom: 24px;
}

.primary-button {
  background-color: var(--primary-color);
  color: #ffffff;
  border: none;
  border-radius: 8px;
  padding: 12px 32px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.15s ease;
  min-width: 220px;
}

.primary-button:hover:not(:disabled) {
  background-color: var(--primary-hover);
}

.primary-button:disabled {
  background-color: var(--primary-disabled);
  cursor: not-allowed;
}

.status-box {
  margin-top: 14px;
  padding: 10px 16px;
  background-color: #eff6ff;
  border: 1px solid #bfdbfe;
  color: #1e40af;
  border-radius: 6px;
  font-size: 0.875rem;
}

.error-box {
  margin-top: 14px;
  padding: 12px 16px;
  background-color: var(--error-bg);
  border: 1px solid var(--error-border);
  color: var(--error-color);
  border-radius: 6px;
  font-size: 0.9rem;
  font-weight: 500;
}

/* 結果表示 */
.result-section {
  background: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: var(--radius);
  padding: 20px;
  text-align: center;
  margin-bottom: 24px;
}

.result-title {
  font-size: 1.25rem;
  margin-bottom: 16px;
}

.canvas-wrapper {
  max-width: 500px;
  margin: 0 auto 16px;
  background-color: #e2e8f0;
  background-image: 
    linear-gradient(45deg, #cbd5e1 25%, transparent 25%), 
    linear-gradient(-45deg, #cbd5e1 25%, transparent 25%), 
    linear-gradient(45deg, transparent 75%, #cbd5e1 75%), 
    linear-gradient(-45deg, transparent 75%, #cbd5e1 75%);
  background-size: 20px 20px;
  background-position: 0 0, 0 10px, 10px -10px, -10px 0px;
  border-radius: 8px;
  overflow: hidden;
  box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
}

#result-canvas {
  width: 100%;
  height: auto;
  display: block;
}

.download-button {
  background-color: #047857;
  color: #ffffff;
  border: none;
  border-radius: 8px;
  padding: 10px 24px;
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.15s ease;
}

.download-button:hover:not(:disabled) {
  background-color: #065f46;
}

.app-footer {
  text-align: center;
  font-size: 0.8rem;
  color: var(--text-muted);
  padding: 16px 0;
}

/* アクセシビリティ・WCAG */
button:focus-visible, input:focus-visible, .file-input:focus-visible + .preview-content {
  outline: 3px solid var(--focus-ring);
  outline-offset: 2px;
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}

/* AI仕上げ */
.ai-button {
  background-color: #7c3aed;
  color: #ffffff;
  border: none;
  border-radius: 8px;
  padding: 10px 24px;
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  transition: background-color 0.15s ease;
}

.ai-button:hover:not(:disabled) {
  background-color: #6d28d9;
}

.ai-button:disabled {
  opacity: 0.65;
  cursor: wait;
}

.result-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  justify-content: center;
}

.ai-result {
  margin-top: 20px;
  border-top: 1px solid var(--border-color);
  padding-top: 16px;
}

.ai-result-title {
  font-size: 1.05rem;
  margin-bottom: 10px;
}

.ai-result img {
  max-width: 100%;
  border-radius: 8px;
  box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
  margin-bottom: 12px;
}

/* AI仕上げの設定パネル */
.settings-panel {
  background: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: var(--radius);
  padding: 14px 18px;
  margin-bottom: 24px;
}

.settings-panel summary {
  cursor: pointer;
  font-weight: 600;
}

.settings-body {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-top: 12px;
}

.key-row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  align-items: center;
  font-size: 0.9rem;
}

.key-row input[type="password"] {
  flex: 1;
  min-width: 200px;
  padding: 8px 10px;
  border: 1px solid var(--border-color);
  border-radius: 6px;
  font-size: 0.9rem;
}

.key-row select {
  padding: 8px;
  border: 1px solid var(--border-color);
  border-radius: 6px;
  font-size: 0.85rem;
  background: var(--card-bg);
}

.settings-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  align-items: center;
  font-size: 0.85rem;
}

.settings-note {
  font-size: 0.8rem;
  color: var(--text-muted);
}

.key-status {
  font-size: 0.8rem;
  color: var(--accent-green);
}