Size of my icons

[gerbenz (Gerben)]

hello,

how can I resize my icons?
it is custom-button card

type: custom:button-card
state:

• value: ‘on’
  spin: true
  icon: ‘’
  primary_info: name
  secondary_info: state
  tap_action:
  action: more-info
  layout: vertical
  entity: fan.ventilator_slk_gerben_stefanie
  name: Vent. Slk. Gerben Stefanie
  card_mod:
  style: |
  ha-card {
  border-width: 0;
  background: none;
  }