:root {
      --color-bg: #f5f5f5;
      --color-bg-secondary: #ebebeb;
      --color-surface: #fafafa;
      --color-surface-hover: #e0e0e0;
      --color-border: #d0d0d0;
      --color-border-hover: #b0b0b0;
      --color-text: #111111;
      --color-text-secondary: #555555;
      --color-text-tertiary: #888888;
      --color-accent: #333333;
      --color-accent-hover: #444444;
      --color-accent-muted: rgba(0, 0, 0, 0.06);
    }

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

    body {
      font-family: 'BIZ UDPMincho', 'Noto Serif JP', serif;
      background: var(--color-bg);
      color: var(--color-text);
      line-height: 1.7;
      min-height: 100vh;
      -webkit-font-smoothing: antialiased;
      -moz-osx-font-smoothing: grayscale;
    }

    body::before {
      content: '';
      position: fixed;
      inset: 0;
      pointer-events: none;
      opacity: 0.015;
      z-index: 50;
      background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 256 256' 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%25' height='100%25' filter='url(%23noise)'/%3E%3C/svg%3E");
    }

    /* ヘッダー */
    header {
      background: linear-gradient(135deg, #1a1a1a 0%, #6b6b6b 100%);
    }

    header .header-inner {
      max-width: 1440px;
      margin: 0 auto;
      padding: 20px 24px;
      text-align: center;
    }

    header h1 {
      font-size: 1.5rem;
      font-weight: 700;
      color: #fff;
    }

    header p {
      font-size: 1rem;
      color: rgba(255, 255, 255, 0.7);
      margin-top: 4px;
    }

    .container {
      max-width: 1100px;
      margin: 0 auto;
      padding: 32px 24px 64px;
    }

    .layout {
      display: grid;
      grid-template-columns: 340px 1fr;
      gap: 24px;
      align-items: start;
    }

    .sidebar {
      display: flex;
      flex-direction: column;
      gap: 16px;
      position: sticky;
      top: 20px;
    }

    .card {
      background: var(--color-surface);
      border-radius: 12px;
      padding: 24px;
      border: 1px solid var(--color-border);
    }

    .card-title {
      font-size: 1rem;
      font-weight: 700;
      margin-bottom: 16px;
      color: var(--color-text);
    }

    /* ドロップゾーン */
    .drop-zone {
      border: 2px dashed var(--color-border);
      border-radius: 12px;
      padding: 32px 16px;
      text-align: center;
      cursor: pointer;
      transition: all 0.2s;
      background: var(--color-bg-secondary);
      position: relative;
    }

    .drop-zone:hover,
    .drop-zone.dragover {
      border-color: var(--color-accent);
      background: var(--color-accent-muted);
    }

    .drop-zone-icon {
      width: 56px;
      height: 56px;
      border-radius: 12px;
      display: flex;
      align-items: center;
      justify-content: center;
      margin: 0 auto 12px;
      background: var(--color-surface);
      transition: background 0.2s;
    }

    .drop-zone:hover .drop-zone-icon {
      background: var(--color-accent-muted);
    }

    .drop-zone-icon svg {
      width: 28px;
      height: 28px;
      color: var(--color-text-tertiary);
      transition: color 0.2s;
    }

    .drop-zone:hover .drop-zone-icon svg {
      color: var(--color-accent);
    }

    .drop-zone-text {
      font-size: 1.125rem;
      font-weight: 600;
      color: var(--color-text);
      display: block;
      margin-bottom: 4px;
    }

    .drop-zone-sub {
      font-size: 1rem;
      color: var(--color-text-secondary);
    }

    .drop-zone-sub .accent {
      color: var(--color-accent);
      font-weight: 500;
    }

    .drop-zone input[type="file"] {
      position: absolute;
      inset: 0;
      opacity: 0;
      cursor: pointer;
    }

    /* プレビュー画像 */
    .preview-wrap {
      margin-top: 16px;
      display: none;
    }

    .preview-wrap.active {
      display: block;
    }

    .preview-img {
      width: 100%;
      border-radius: 8px;
      display: block;
      border: 1px solid var(--color-border);
    }

    .file-name {
      font-size: 1rem;
      color: var(--color-text-tertiary);
      margin-top: 8px;
      text-align: center;
      word-break: break-all;
      font-family: 'JetBrains Mono', monospace;
    }

    /* 設定 */
    .setting-row {
      display: flex;
      justify-content: space-between;
      align-items: center;
      margin-bottom: 12px;
    }

    .setting-row:last-child {
      margin-bottom: 0;
    }

    .setting-label {
      font-size: 1rem;
      font-weight: 600;
      color: var(--color-text-secondary);
    }

    .setting-value {
      display: flex;
      align-items: center;
      gap: 8px;
    }

    .setting-value input[type="range"] {
      width: 100px;
      accent-color: var(--color-accent);
    }

    .setting-value span {
      font-size: 1rem;
      font-weight: 600;
      color: var(--color-text);
      min-width: 24px;
      text-align: right;
      font-family: 'JetBrains Mono', monospace;
    }

    .btn-extract {
      width: 100%;
      padding: 12px;
      background: var(--color-accent);
      color: #fff;
      border: none;
      border-radius: 8px;
      font-size: 1rem;
      font-weight: 700;
      cursor: pointer;
      transition: background 0.15s;
      font-family: inherit;
    }

    .btn-extract:hover {
      background: var(--color-accent-hover);
    }

    .btn-extract:disabled {
      opacity: 0.4;
      cursor: not-allowed;
    }

    /* メインエリア */
    .main {
      display: flex;
      flex-direction: column;
      gap: 24px;
    }

    .empty-state {
      text-align: center;
      padding: 80px 20px;
      color: var(--color-text-tertiary);
    }

    .empty-state-icon {
      width: 56px;
      height: 56px;
      border-radius: 12px;
      display: flex;
      align-items: center;
      justify-content: center;
      margin: 0 auto 16px;
      background: var(--color-bg-secondary);
    }

    .empty-state-icon svg {
      width: 28px;
      height: 28px;
      color: var(--color-text-tertiary);
    }

    .empty-state-text {
      font-size: 1.125rem;
    }

    /* 使い方ステップ */
    .steps {
      display: grid;
      grid-template-columns: 1fr 1fr 1fr;
      gap: 32px;
      margin-top: 32px;
    }

    .step {
      text-align: center;
    }

    .step-number {
      font-family: 'JetBrains Mono', monospace;
      font-size: 1rem;
      font-weight: 500;
      color: var(--color-accent);
      margin-bottom: 8px;
      display: block;
    }

    .step-title {
      font-size: 1rem;
      font-weight: 600;
      color: var(--color-text);
    }

    .step-desc {
      font-size: 1rem;
      color: var(--color-text-tertiary);
      margin-top: 2px;
    }

    /* 抽出色一覧 */
    .palette-grid {
      display: grid;
      grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
      gap: 12px;
    }

    .palette-item {
      border-radius: 12px;
      overflow: hidden;
      border: 1px solid var(--color-border);
      cursor: pointer;
      transition: transform 0.15s, border-color 0.15s;
      background: var(--color-surface);
    }

    .palette-item:hover {
      transform: translateY(-2px);
      border-color: var(--color-accent);
    }

    .palette-swatch {
      height: 80px;
      position: relative;
    }

    .palette-percent {
      position: absolute;
      top: 8px;
      right: 8px;
      background: rgba(0, 0, 0, 0.45);
      color: #fff;
      font-size: 1rem;
      padding: 2px 8px;
      border-radius: 4px;
      font-weight: 500;
      font-family: 'JetBrains Mono', monospace;
    }

    .palette-info {
      padding: 10px 12px;
    }

    .palette-hex {
      font-size: 1rem;
      font-weight: 500;
      color: var(--color-text);
      font-family: 'JetBrains Mono', monospace;
    }

    .palette-rgb {
      font-size: 1rem;
      color: var(--color-text-tertiary);
      margin-top: 2px;
      font-family: 'JetBrains Mono', monospace;
    }

    .copied-toast {
      position: fixed;
      bottom: 24px;
      left: 50%;
      transform: translateX(-50%) translateY(80px);
      background: var(--color-text);
      color: var(--color-surface);
      padding: 12px 24px;
      border-radius: 8px;
      font-size: 1rem;
      font-weight: 600;
      opacity: 0;
      transition: all 0.3s;
      z-index: 100;
      pointer-events: none;
    }

    .copied-toast.show {
      transform: translateX(-50%) translateY(0);
      opacity: 1;
    }

    /* パレット提案 */
    .suggestion-section {
      margin-top: 8px;
    }

    .suggestion-row {
      display: flex;
      align-items: center;
      gap: 12px;
      padding: 10px 12px;
      border-radius: 8px;
      transition: background 0.15s;
      cursor: pointer;
    }

    .suggestion-row:hover {
      background: var(--color-surface-hover);
    }

    .suggestion-swatch {
      width: 40px;
      height: 40px;
      border-radius: 8px;
      flex-shrink: 0;
      border: 1px solid var(--color-border);
    }

    .suggestion-detail {
      flex: 1;
      min-width: 0;
    }

    .suggestion-role {
      font-size: 1rem;
      font-weight: 600;
      color: var(--color-text);
    }

    .suggestion-hex {
      font-size: 1rem;
      color: var(--color-text-tertiary);
      font-family: 'JetBrains Mono', monospace;
    }

    .suggestion-contrast {
      font-size: 1rem;
      padding: 2px 8px;
      border-radius: 4px;
      font-weight: 500;
      flex-shrink: 0;
      font-family: 'JetBrains Mono', monospace;
    }

    .contrast-pass {
      background: #d4edda;
      color: #155724;
    }

    .contrast-fail {
      background: #f8d7da;
      color: #721c24;
    }

    /* CSSエクスポート */
    .export-section {
      margin-top: 8px;
    }

    .export-tabs {
      display: flex;
      gap: 4px;
      margin-bottom: 12px;
    }

    .export-tab {
      padding: 8px 16px;
      border: 1px solid var(--color-border);
      border-radius: 6px;
      background: var(--color-surface);
      cursor: pointer;
      font-size: 1rem;
      font-weight: 600;
      color: var(--color-text-secondary);
      transition: all 0.15s;
      font-family: inherit;
    }

    .export-tab:hover {
      border-color: var(--color-border-hover);
      background: var(--color-surface-hover);
    }

    .export-tab.active {
      background: var(--color-accent);
      color: #fff;
      border-color: var(--color-accent);
    }

    .export-code {
      background: #1e1e1e;
      color: #d4d4d4;
      padding: 16px;
      border-radius: 8px;
      font-family: 'JetBrains Mono', monospace;
      font-size: 1rem;
      line-height: 1.6;
      overflow-x: auto;
      white-space: pre;
      position: relative;
    }

    .btn-copy-code {
      position: absolute;
      top: 8px;
      right: 8px;
      padding: 6px 12px;
      border: 1px solid rgba(255, 255, 255, 0.15);
      border-radius: 4px;
      background: rgba(255, 255, 255, 0.08);
      color: #d4d4d4;
      font-size: 1rem;
      cursor: pointer;
      transition: all 0.15s;
      font-family: 'JetBrains Mono', monospace;
    }

    .btn-copy-code:hover {
      background: rgba(255, 255, 255, 0.15);
    }

    /* プレビューカード */
    .preview-section {
      margin-top: 8px;
    }

    .preview-demo {
      border-radius: 12px;
      overflow: hidden;
      border: 1px solid var(--color-border);
    }

    .preview-header {
      padding: 24px;
      text-align: center;
    }

    .preview-header h3 {
      font-size: 1.5rem;
      font-weight: 700;
      margin-bottom: 8px;
    }

    .preview-header p {
      font-size: 1rem;
    }

    .preview-body {
      padding: 24px;
    }

    .preview-body p {
      font-size: 1rem;
      line-height: 1.8;
      margin-bottom: 16px;
    }

    .preview-btn {
      display: inline-block;
      padding: 12px 32px;
      border-radius: 8px;
      font-size: 1rem;
      font-weight: 700;
      border: none;
      cursor: default;
    }

    .preview-card-row {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 12px;
      margin-top: 16px;
    }

    .preview-mini-card {
      padding: 16px;
      border-radius: 8px;
    }

    .preview-mini-card h4 {
      font-size: 1rem;
      font-weight: 700;
      margin-bottom: 4px;
    }

    .preview-mini-card p {
      font-size: 1rem;
      margin-bottom: 0;
    }

    /* フッター */
    footer {
      background: linear-gradient(135deg, #6b6b6b 0%, #1a1a1a 100%);
      padding: 16px 0;
      margin-top: auto;
    }

    footer .footer-inner {
      max-width: 1440px;
      margin: 0 auto;
      padding: 0 24px;
      display: flex;
      align-items: center;
      justify-content: space-between;
    }

    footer p {
      font-size: 1rem;
      color: rgba(255, 255, 255, 0.5);
    }

    footer a {
      color: rgba(255, 255, 255, 0.8);
      text-decoration: none;
      transition: color 0.15s;
    }

    footer a:hover {
      color: #fff;
    }

    .footer-links {
      display: flex;
      align-items: center;
      gap: 16px;
    }

    .footer-links a {
      font-size: 1rem;
      color: rgba(255, 255, 255, 0.7);
      transition: color 0.15s;
    }

    .footer-links a:hover {
      color: #fff;
    }

    /* 保存パレット */
    .saved-empty {
      font-size: 1rem;
      color: var(--color-text-tertiary);
      text-align: center;
      padding: 12px 0;
    }

    .saved-list {
      display: flex;
      flex-direction: column;
      gap: 12px;
    }

    .saved-item {
      border: 1px solid var(--color-border);
      border-radius: 8px;
      overflow: hidden;
      transition: border-color 0.15s;
    }

    .saved-item:hover {
      border-color: var(--color-border-hover);
    }

    .saved-colors {
      display: flex;
      height: 32px;
    }

    .saved-colors span {
      flex: 1;
    }

    .saved-meta {
      display: flex;
      align-items: center;
      justify-content: space-between;
      padding: 8px 10px;
      gap: 8px;
    }

    .saved-name {
      font-size: 1rem;
      font-weight: 600;
      color: var(--color-text);
      flex: 1;
      min-width: 0;
      overflow: hidden;
      text-overflow: ellipsis;
      white-space: nowrap;
    }

    .saved-date {
      font-size: 1rem;
      color: var(--color-text-tertiary);
      font-family: 'JetBrains Mono', monospace;
      flex-shrink: 0;
    }

    .saved-actions {
      display: flex;
      gap: 4px;
      flex-shrink: 0;
    }

    .saved-actions button {
      background: none;
      border: 1px solid var(--color-border);
      border-radius: 4px;
      cursor: pointer;
      padding: 4px 8px;
      font-size: 1rem;
      color: var(--color-text-secondary);
      transition: all 0.15s;
      font-family: inherit;
      line-height: 1;
    }

    .saved-actions button:hover {
      border-color: var(--color-border-hover);
      color: var(--color-text);
    }

    .saved-actions button.delete-btn:hover {
      border-color: #c0392b;
      color: #c0392b;
    }

    .btn-save {
      width: 100%;
      padding: 10px;
      background: var(--color-surface);
      color: var(--color-text);
      border: 1px solid var(--color-border);
      border-radius: 8px;
      font-size: 1rem;
      font-weight: 600;
      cursor: pointer;
      transition: all 0.15s;
      font-family: inherit;
      margin-top: 12px;
    }

    .btn-save:hover {
      border-color: var(--color-border-hover);
      background: var(--color-surface-hover);
    }

    .btn-save:disabled {
      opacity: 0.4;
      cursor: not-allowed;
    }

    .save-input-row {
      display: none;
      gap: 8px;
      margin-top: 12px;
    }

    .save-input-row.active {
      display: flex;
    }

    .save-input-row input {
      flex: 1;
      padding: 8px 10px;
      border: 1px solid var(--color-border);
      border-radius: 6px;
      font-size: 1rem;
      font-family: inherit;
      background: var(--color-surface);
      color: var(--color-text);
      outline: none;
    }

    .save-input-row input:focus {
      border-color: var(--color-accent);
    }

    .save-input-row button {
      padding: 8px 14px;
      background: var(--color-accent);
      color: #fff;
      border: none;
      border-radius: 6px;
      font-size: 1rem;
      font-weight: 600;
      cursor: pointer;
      font-family: inherit;
      white-space: nowrap;
      transition: background 0.15s;
    }

    .save-input-row button:hover {
      background: var(--color-accent-hover);
    }

    @media (max-width: 768px) {
      .layout {
        grid-template-columns: 1fr;
      }

      .sidebar {
        position: static;
      }

      footer .footer-inner {
        flex-direction: column;
        gap: 12px;
        text-align: center;
      }

      .footer-links { flex-wrap: wrap; justify-content: center; }

      .preview-card-row {
        grid-template-columns: 1fr;
      }

      .palette-grid {
        grid-template-columns: repeat(auto-fill, minmax(120px, 1fr));
      }

      .steps {
        grid-template-columns: 1fr;
        gap: 16px;
      }
    }

    /* ============ i18n: 言語切替リンク ============ */
    header .header-inner {
      position: relative;
    }
    .lang-switch {
      position: absolute;
      top: 50%;
      right: 24px;
      transform: translateY(-50%);
      display: inline-block;
      padding: 4px 12px;
      border: 1px solid rgba(255, 255, 255, 0.4);
      border-radius: 999px;
      color: #fff;
      font-size: 1rem;
      text-decoration: none;
    }
    .lang-switch:hover {
      background: rgba(255, 255, 255, 0.15);
    }

    /* ---- FAQ ---- */
    .faq-section {
      max-width: 820px;
      margin: 0 auto;
      padding: 0 24px 24px;
    }
    .faq-heading {
      font-size: 1.5rem;
      margin: 0 0 16px;
      color: var(--color-text);
    }
    .faq {
      margin: 0;
    }
    .faq dt {
      font-weight: 700;
      font-size: 1.05rem;
      color: var(--color-text);
      margin-top: 18px;
    }
    .faq dd {
      margin: 6px 0 0;
      color: var(--color-text-secondary);
      line-height: 1.8;
    }