body {
    background: #111;
    color: #fff;
    font-family: 'Segoe UI', monospace;
    text-align: center;
    padding: 30px;
  }
  body, pre, textarea {
    font-family: Consolas, 'Courier New', monospace;
    font-size: 14px;
    line-height: 1.45em;
    letter-spacing: 0;
    tab-size: 2;
  }
  h1 { margin-bottom: 10px; }
  .container {
    display: inline-block;
    text-align: left;
    width: 90%;
    max-width: 900px;
  }
  .editor-wrapper {
    display: flex;
    position: relative;
    border-radius: 8px;
    border: 1px solid #333;
    overflow: hidden;
    min-height: 320px;
  }
  .line-numbers {
    background: #1a1a1a;
    color: #888;
    padding: 10px 6px;
    text-align: right;
    user-select: none;
  }
  pre#highlight {
    flex: 1;
    margin: 0;
    padding: 10px;
    background: #222;
    color: #eee;
    text-align: left;
    white-space: pre-wrap;
    word-wrap: break-word;
    font-size: 14px;
    line-height: 1.4em;
    overflow-y: auto;
  }
  textarea#jsonInput {
    position: absolute;
    top: 0;
    left: 20px;
    width: calc(100% - 50px);
    height: 100%;
    resize: none;
    border: none;
    outline: none;
    background: transparent;
    color: transparent;
    caret-color: #00ffcc;
    line-height: 1.4em;
    padding: 10px;
    font-size: 14px;
    tab-size: 2; /* keeps indent width equal to highlight */
  }
  .status { margin-top: 15px; font-size: 1.1em; }
  .valid { color: #00ff99; }
  .invalid { color: #ff5555; }
  pre#result {
    background: rgba(255,255,255,0.05);
    padding: 10px;
    border-radius: 8px;
    margin-top: 10px;
    text-align: left;
    color: #00ffcc;
    overflow-x: auto;
  }

  /* Syntax highlight colors */
  .key { color: #9CDCFE; }
  .string { color: #CE9178; }
  .number { color: #B5CEA8; }
  .boolean { color: #569CD6; }
  .null { color: #569CD6; }

  /* Visual red highlight overlay via CSS class instead of inline span injection */
  .highlight-error-line {
    background-color: rgba(255, 0, 0, 0.25);
    display: block;
    width: 100%;
  }