.subtitle { font-size: 12px; color: var(--ink-light); font-weight: 300; letter-spacing: 0.1em; border-left: 2px solid var(--accent); padding-left: 10px; }
.panel-header { padding: 10px 16px; border-bottom: 1px solid var(--border); background: var(--bg); display:flex; justify-content:space-between; align-items:center; gap:12px; }
    .panel-label { font-size: 10px; letter-spacing: 0.2em; color: var(--ink-light); text-transform: uppercase; }
    .panel-body { padding: 18px; }
.hidden { display:none !important; }
    @media (max-width: 900px) {
}
  
    /* ── File rename input readability fix ── */
    #prefixInput,
    #suffixInput,
    #startInput,
    #digitInput {
      width: 100%;
      border: 1px solid var(--border);
      background: #fff;
      color: var(--ink);
      font: inherit;
      font-size: 13px;
      font-weight: 400;
      padding: 10px 12px;
      border-radius: 6px;
      outline: none;
      box-sizing: border-box;
      line-height: 1.4;
      letter-spacing: 0;
    }
    #prefixInput:focus,
    #suffixInput:focus,
    #startInput:focus,
    #digitInput:focus {
      border-color: var(--blue);
      background: #fff;
      box-shadow: none;
    }
    #prefixInput::placeholder,
    #suffixInput::placeholder,
    #startInput::placeholder,
    #digitInput::placeholder {
      color: var(--ink-light);
      font-weight: 400;
    }