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

  :root {
    --bg: #080c10;
    --surface: #0d1117;
    --surface2: #161b22;
    --border: rgba(255,255,255,0.07);
    --accent: #ff0033;
    --accent2: #ff4d6d;
    --text: #e6edf3;
    --muted: #7d8590;
    --font-mono: 'Space Mono', monospace;
    --font-body: 'DM Sans', sans-serif;
  }

  html, body {
    height: 100%;
    background: var(--bg);
    color: var(--text);
    font-family: var(--font-body);
    font-size: 15px;
    line-height: 1.6;
  }

  /* Grid noise background */
  body::before {
    content: '';
    position: fixed;
    inset: 0;
    background-image:
      linear-gradient(rgba(255,0,51,0.03) 1px, transparent 1px),
      linear-gradient(90deg, rgba(255,0,51,0.03) 1px, transparent 1px);
    background-size: 40px 40px;
    pointer-events: none;
    z-index: 0;
  }

  body::after {
    content: '';
    position: fixed;
    top: -200px;
    left: 50%;
    transform: translateX(-50%);
    width: 600px;
    height: 600px;
    background: radial-gradient(circle, rgba(255,0,51,0.07) 0%, transparent 70%);
    pointer-events: none;
    z-index: 0;
  }

  /* GitHub banner */
  .github-banner {
    position: relative;
    z-index: 10;
    width: 100%;
    background: var(--surface);
    border-bottom: 1px solid var(--border);
    padding: 10px 24px;
    display: flex;
    align-items: center;
    justify-content: space-between;
  }

  .github-banner .banner-left {
    font-family: var(--font-mono);
    font-size: 12px;
    color: var(--muted);
    letter-spacing: 0.05em;
  }

  .github-banner .banner-left span {
    color: var(--accent);
  }

  .github-link {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 7px 16px;
    background: var(--surface2);
    border: 1px solid var(--border);
    border-radius: 8px;
    text-decoration: none;
    color: var(--text);
    font-family: var(--font-mono);
    font-size: 12px;
    font-weight: 700;
    letter-spacing: 0.04em;
    transition: border-color 0.2s, box-shadow 0.2s, color 0.2s;
  }

  .github-link:hover {
    border-color: rgba(255,255,255,0.2);
    box-shadow: 0 0 0 3px rgba(255,255,255,0.04);
    color: #fff;
  }

  .github-link svg {
    width: 16px;
    height: 16px;
    fill: currentColor;
    flex-shrink: 0;
  }

  .github-link .gh-username {
    color: var(--muted);
    font-weight: 400;
  }

  .github-link:hover .gh-username {
    color: var(--text);
  }

  /* Page layout */
  .page {
    position: relative;
    z-index: 1;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 60px 20px 80px;
  }

  /* Header */
  header {
    text-align: center;
    margin-bottom: 56px;
  }

  .logo {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 20px;
  }

  .logo-icon {
    width: 36px;
    height: 36px;
    background: var(--accent);
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
  }

  .logo-icon svg {
    width: 18px;
    height: 18px;
  }

  .logo-text {
    font-family: var(--font-mono);
    font-size: 15px;
    font-weight: 700;
    letter-spacing: 0.05em;
    color: var(--text);
  }

  h1 {
    font-size: clamp(32px, 5vw, 52px);
    font-weight: 600;
    letter-spacing: -0.02em;
    line-height: 1.1;
    margin-bottom: 14px;
    background: linear-gradient(135deg, #fff 0%, rgba(255,255,255,0.5) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
  }

  .subtitle {
    color: var(--muted);
    font-size: 16px;
    font-weight: 300;
    max-width: 420px;
    margin: 0 auto;
  }

  /* Main card */
  .card {
    width: 100%;
    max-width: 680px;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 16px;
    padding: 32px;
    margin-bottom: 24px;
  }

  .input-group {
    margin-bottom: 24px;
  }

  label {
    display: block;
    font-size: 12px;
    font-weight: 600;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--muted);
    margin-bottom: 8px;
    font-family: var(--font-mono);
  }

  .input-row {
    display: flex;
    gap: 10px;
  }

  input[type="number"]::-webkit-outer-spin-button,
  input[type="number"]::-webkit-inner-spin-button {
    -webkit-appearance: none;
    margin: 0;
  }

  input[type="number"] {
    -moz-appearance: textfield;
    appearance: textfield;
  }

  input[type="text"],
  input[type="number"] {
    width: 100%;
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: 10px;
    padding: 12px 16px;
    color: var(--text);
    font-family: var(--font-mono);
    font-size: 13px;
    outline: none;
    transition: border-color 0.2s, box-shadow 0.2s;
  }


  select {
    width: 100%;
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: 10px;
    padding: 12px 16px;
    color: var(--text);
    font-family: var(--font-mono);
    font-size: 13px;
    outline: none;
    transition: border-color 0.2s, box-shadow 0.2s;
    appearance: none;
  }

  input[type="text"]:focus,
  input[type="number"]:focus,
  select:focus {
    border-color: rgba(255,0,51,0.5);
    box-shadow: 0 0 0 3px rgba(255,0,51,0.08);
  }

  input[type="color"] {
    width: 44px;
    height: 44px;
    border: 1px solid var(--border);
    border-radius: 8px;
    background: var(--bg);
    padding: 4px;
    cursor: pointer;
    flex-shrink: 0;
  }

  .options-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
    margin-bottom: 24px;
  }

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

  .color-row input[type="text"] {
    flex: 1;
  }

  button.generate {
    width: 100%;
    padding: 14px 24px;
    background: var(--accent);
    color: white;
    border: none;
    border-radius: 10px;
    font-family: var(--font-mono);
    font-size: 13px;
    font-weight: 700;
    letter-spacing: 0.05em;
    cursor: pointer;
    transition: background 0.2s, transform 0.1s, box-shadow 0.2s;
    text-transform: uppercase;
  }

  button.generate:hover {
    background: var(--accent2);
    box-shadow: 0 4px 20px rgba(255,0,51,0.3);
  }

  button.generate:active {
    transform: scale(0.99);
  }

  button.generate:disabled {
    background: #333;
    cursor: not-allowed;
    box-shadow: none;
  }

  /* Result */
  .result-card {
    width: 100%;
    max-width: 680px;
    display: none;
  }

  .result-card.visible {
    display: block;
    animation: slideUp 0.3s ease;
  }

  @keyframes slideUp {
    from { opacity: 0; transform: translateY(16px); }
    to { opacity: 1; transform: translateY(0); }
  }

  .result-section {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 16px;
    padding: 24px;
    margin-bottom: 16px;
  }

  .result-section h3 {
    font-family: var(--font-mono);
    font-size: 11px;
    font-weight: 700;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: var(--muted);
    margin-bottom: 16px;
  }

  .preview-wrap {
    display: flex;
    justify-content: center;
    background: var(--bg);
    border-radius: 10px;
    padding: 24px;
    border: 1px solid var(--border);
  }

  .preview-wrap a {
    display: block;
  }

  .preview-wrap img,
  .preview-wrap svg {
    display: block;
    border-radius: 8px;
  }

  .code-block {
    position: relative;
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: 10px;
    overflow: hidden;
  }

  .code-block pre {
    padding: 16px;
    font-family: var(--font-mono);
    font-size: 12px;
    color: var(--muted);
    overflow-x: auto;
    line-height: 1.7;
    white-space: pre-wrap;
    word-break: break-all;
  }

  .code-block pre em {
    color: #7ee787;
    font-style: normal;
  }

  .copy-btn {
    position: absolute;
    top: 10px;
    right: 10px;
    background: var(--surface2);
    border: 1px solid var(--border);
    border-radius: 6px;
    padding: 5px 10px;
    font-family: var(--font-mono);
    font-size: 11px;
    color: var(--muted);
    cursor: pointer;
    transition: all 0.15s;
  }

  .copy-btn:hover {
    color: var(--text);
    border-color: rgba(255,255,255,0.2);
  }

  .copy-btn.copied {
    color: #7ee787;
    border-color: rgba(126,231,135,0.3);
  }

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

  .tab {
    padding: 6px 14px;
    background: transparent;
    border: 1px solid transparent;
    border-radius: 6px;
    font-family: var(--font-mono);
    font-size: 11px;
    color: var(--muted);
    cursor: pointer;
    transition: all 0.15s;
  }

  .tab.active {
    background: var(--surface2);
    border-color: var(--border);
    color: var(--text);
  }

  .error-msg {
    display: none;
    background: rgba(255,0,51,0.08);
    border: 1px solid rgba(255,0,51,0.2);
    border-radius: 10px;
    padding: 12px 16px;
    color: #ff6b8a;
    font-family: var(--font-mono);
    font-size: 12px;
    margin-bottom: 16px;
  }

  .error-msg.visible {
    display: block;
  }

  .loading {
    display: none;
    text-align: center;
    padding: 40px;
    color: var(--muted);
    font-family: var(--font-mono);
    font-size: 13px;
  }

  .loading.visible { display: block; }

  .spinner {
    display: inline-block;
    width: 20px;
    height: 20px;
    border: 2px solid var(--border);
    border-top-color: var(--accent);
    border-radius: 50%;
    animation: spin 0.7s linear infinite;
    margin-bottom: 12px;
  }

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

  /* How to use */
  .how-to {
    width: 100%;
    max-width: 680px;
    margin-top: 8px;
  }

  .how-to h2 {
    font-family: var(--font-mono);
    font-size: 11px;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: var(--muted);
    margin-bottom: 12px;
  }

  .steps {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 12px;
  }

  @media (max-width: 560px) {
    .steps { grid-template-columns: 1fr; }
    .options-grid { grid-template-columns: 1fr; }
  }

  .step {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 18px;
  }

  .step-num {
    font-family: var(--font-mono);
    font-size: 11px;
    color: var(--accent);
    font-weight: 700;
    margin-bottom: 6px;
  }

  .step p {
    font-size: 13px;
    color: var(--muted);
    line-height: 1.5;
  }