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

    body {
      background: #f8f9fa;
      color: #1a1a2e;
      font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
      line-height: 1.6;
      min-height: 100vh;
    }

    /* ── Header ── */
    .page-header {
      background: #fff;
      border-bottom: 1px solid #e2e8f0;
      padding: 20px 24px;
      text-align: center;
    }
    .page-header-inner {
      max-width: 1140px; margin: 0 auto;
      display: flex; align-items: center; justify-content: center;
      gap: 16px; position: relative;
    }
    .page-header-back {
      position: absolute; left: 0;
      color: #6b7280; text-decoration: none; font-size: 14px; font-weight: 600;
      display: flex; align-items: center; gap: 4px; transition: color 0.15s;
    }
    .page-header-back:hover { color: #f15b46; }
    .page-header-logo { height: 22px; display: block; }
    .page-header h1 {
      font-size: 24px;
      font-weight: 700;
      color: #1a1a2e;
    }
    .page-header h1 span { color: #f15b46; }
    .page-header p {
      font-size: 15px;
      color: #6b7280;
      margin-top: 4px;
    }

    /* ── Main layout ── */
    .container {
      max-width: 1140px;
      margin: 0 auto;
      padding: 24px 20px 60px;
    }

    .main-layout {
      display: grid;
      grid-template-columns: 1fr;
      gap: 24px;
    }

    @media (min-width: 920px) {
      .main-layout.two-col {
        grid-template-columns: 420px 1fr;
        align-items: start;
      }
    }

    /* ── Card sections ── */
    .card {
      background: #fff;
      border-radius: 12px;
      padding: 24px 28px;
      box-shadow: 0 1px 3px rgba(0,0,0,0.06), 0 1px 2px rgba(0,0,0,0.04);
    }

    .card h2 {
      font-size: 16px;
      font-weight: 700;
      color: #374151;
      margin-bottom: 16px;
      display: flex;
      align-items: center;
      gap: 10px;
    }

    .step-num {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      width: 28px;
      height: 28px;
      background: #f15b46;
      color: #fff;
      border-radius: 50%;
      font-size: 13px;
      font-weight: 700;
      flex-shrink: 0;
    }

    /* ── Step 1: Feed URL ── */
    .feed-row {
      display: flex;
      gap: 10px;
    }

    .feed-input {
      flex: 1;
      padding: 10px 14px;
      border: 1.5px solid #d1d5db;
      border-radius: 8px;
      font-size: 14px;
      font-family: inherit;
      color: #1a1a2e;
      outline: none;
      transition: border-color 0.15s;
    }

    .feed-input:focus { border-color: #f15b46; }
    .feed-input::placeholder { color: #9ca3af; }
    .feed-input:disabled { background: #f3f4f6; color: #9ca3af; }

    .validate-btn {
      padding: 10px 20px;
      background: #f15b46;
      color: #fff;
      border: none;
      border-radius: 8px;
      font-size: 14px;
      font-weight: 600;
      font-family: inherit;
      cursor: pointer;
      transition: background 0.15s, transform 0.1s;
      white-space: nowrap;
    }

    .validate-btn:hover { background: #d94a37; }
    .validate-btn:active { transform: scale(0.97); }
    .validate-btn:disabled { background: #d1d5db; cursor: not-allowed; transform: none; }

    /* Feed status messages */
    .feed-status {
      margin-top: 14px;
      font-size: 14px;
    }

    .feed-loading {
      display: flex;
      align-items: center;
      gap: 10px;
      color: #6b7280;
    }

    .spinner-sm {
      width: 18px;
      height: 18px;
      border: 2.5px solid #d1d5db;
      border-top-color: #f15b46;
      border-radius: 50%;
      animation: spin 0.7s linear infinite;
    }

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

    .feed-error {
      color: #dc2626;
      background: #fef2f2;
      border: 1px solid #fecaca;
      padding: 10px 14px;
      border-radius: 8px;
    }

    .feed-success {
      display: flex;
      align-items: center;
      gap: 14px;
      background: #f0fdf4;
      border: 1px solid #bbf7d0;
      border-radius: 10px;
      padding: 12px 16px;
    }

    .feed-artwork {
      width: 56px;
      height: 56px;
      border-radius: 10px;
      object-fit: cover;
      flex-shrink: 0;
      box-shadow: 0 2px 8px rgba(0,0,0,0.12);
    }

    .feed-meta strong {
      display: block;
      font-size: 15px;
      color: #166534;
    }

    .feed-meta span {
      font-size: 13px;
      color: #4ade80;
    }

    /* ── Step 2: Customize ── */
    .config-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 16px;
      align-items: end;
    }

    .config-field { display: flex; flex-direction: column; gap: 6px; }
    .config-field.full-width { grid-column: 1 / -1; }

    .config-field label {
      font-size: 13px;
      font-weight: 600;
      color: #374151;
    }

    .optional {
      font-weight: 400;
      color: #9ca3af;
    }

    .color-row {
      display: flex;
      align-items: center;
      gap: 10px;
    }

    .color-picker {
      width: 44px;
      height: 44px;
      border: 2px solid #e2e8f0;
      border-radius: 8px;
      cursor: pointer;
      padding: 2px;
      background: none;
    }

    .color-picker::-webkit-color-swatch-wrapper { padding: 0; }
    .color-picker::-webkit-color-swatch { border: none; border-radius: 5px; }
    .color-picker::-moz-color-swatch { border: none; border-radius: 5px; }

    .hex-input {
      width: 90px;
      padding: 8px 10px;
      border: 1.5px solid #d1d5db;
      border-radius: 8px;
      font-size: 14px;
      font-family: 'SF Mono', Monaco, 'Cascadia Code', monospace;
      color: #1a1a2e;
      outline: none;
      transition: border-color 0.15s;
    }

    .hex-input:focus { border-color: #f15b46; }

    .text-input {
      padding: 9px 12px;
      border: 1.5px solid #d1d5db;
      border-radius: 8px;
      font-size: 14px;
      font-family: inherit;
      color: #1a1a2e;
      outline: none;
      transition: border-color 0.15s;
      width: 100%;
    }

    .text-input:focus { border-color: #f15b46; }
    .text-input::placeholder { color: #9ca3af; }

    textarea.text-input {
      resize: vertical;
      min-height: 68px;
      line-height: 1.5;
    }

    .desc-hint {
      font-size: 11px;
      color: #9ca3af;
      margin-top: -2px;
    }

    /* ── Preview ── */
    .preview-section { position: sticky; top: 24px; }

    .preview-container {
      background: #404655;
      border-radius: 16px;
      padding: 4px;
      min-height: 400px;
      display: flex;
      align-items: flex-start;
      justify-content: center;
      transition: background 0.15s;
    }

    .preview-iframe {
      width: 100%;
      max-width: 680px;
      height: 600px;
      border: none;
      border-radius: 14px;
      overflow: hidden;
      display: block;
    }

    .preview-loading {
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      gap: 12px;
      padding: 80px 20px;
      color: #6b7280;
      font-size: 14px;
    }

    /* ── Step 3: Embed Code ── */
    .code-block {
      position: relative;
      background: #1e293b;
      border-radius: 8px;
      padding: 16px 18px;
      overflow-x: auto;
    }

    .code-block code {
      color: #e2e8f0;
      font-family: 'SF Mono', Monaco, 'Cascadia Code', Consolas, monospace;
      font-size: 13px;
      white-space: pre-wrap;
      word-break: break-all;
      line-height: 1.6;
    }

    .code-block .attr-name { color: #7dd3fc; }
    .code-block .attr-value { color: #86efac; }
    .code-block .tag { color: #f9a8d4; }

    .copy-row {
      display: flex;
      align-items: center;
      gap: 12px;
      margin-top: 12px;
    }

    .copy-btn {
      padding: 8px 18px;
      background: #f15b46;
      color: #fff;
      border: none;
      border-radius: 8px;
      font-size: 13px;
      font-weight: 600;
      font-family: inherit;
      cursor: pointer;
      transition: background 0.15s, transform 0.1s;
    }

    .copy-btn:hover { background: #d94a37; }
    .copy-btn:active { transform: scale(0.97); }

    .copy-feedback {
      font-size: 13px;
      color: #16a34a;
      font-weight: 600;
      opacity: 0;
      transition: opacity 0.2s;
    }

    .copy-feedback.is-visible { opacity: 1; }

    .embed-note {
      margin-top: 12px;
      font-size: 13px;
      color: #6b7280;
      line-height: 1.5;
    }

    /* ── Size Selector ── */
    .size-selector {
      display: grid;
      grid-template-columns: 1fr 1fr 1fr;
      gap: 10px;
      margin-bottom: 20px;
    }

    .size-option {
      background: #f8f9fa;
      border: 2px solid #e2e8f0;
      border-radius: 10px;
      padding: 14px 12px;
      cursor: pointer;
      text-align: center;
      transition: border-color 0.15s, background 0.15s, box-shadow 0.15s;
    }

    .size-option:hover {
      border-color: #f15b46;
      background: #fff;
    }

    .size-option.is-active {
      border-color: #f15b46;
      background: rgba(241, 91, 70, 0.04);
      box-shadow: 0 0 0 1px #f15b46;
    }

    .size-option-icon {
      display: flex;
      align-items: center;
      justify-content: center;
      margin-bottom: 8px;
      color: #6b7280;
    }

    .size-option.is-active .size-option-icon { color: #f15b46; }

    .size-option-name {
      font-size: 14px;
      font-weight: 700;
      color: #374151;
      margin-bottom: 2px;
    }

    .size-option.is-active .size-option-name { color: #f15b46; }

    .size-option-desc {
      font-size: 11px;
      color: #9ca3af;
      line-height: 1.4;
    }

    /* ── Utility ── */
    .hidden { display: none !important; }

    /* ── Mobile adjustments ── */
    @media (max-width: 600px) {
      .feed-row { flex-direction: column; }
      .config-grid { grid-template-columns: 1fr; }
      .card { padding: 20px; }
      .page-header h1 { font-size: 20px; }
      .size-selector { grid-template-columns: 1fr; }
    }