<style>
/* Target Zoho form container */
iframe[src*="zoho.com"] {
  max-width: 500px !important;   /* shrink width */
  height: auto !important;       /* let height adjust */
  display: block;
  margin: 0 auto;                /* center on page */
  border: none;
}

/* (optional) shrink inside inputs/text */
iframe[src*="zoho.com"] * {
  font-size: 14px !important;    /* smaller text */
}
</style>
