Checkbox customisé en CSS, également disponible pour les boutons radio : https://www.w3schools.com/howto/howto_css_custom_checkbox.asp
<label class="check-label"><input type="checkbox" name="activite" value="value 1"><span class="checkmark"></span>Text</label>
.check-label {
width: 100%;
box-sizing: border-box;
border-radius: 3px;
border: 1px solid #e0d0d0;
color: #777;
font-size: 16px;
background-color: #eef2f7;
margin: 5px 0;
padding: 15px 20px 15px 60px;
position: relative;
}
.check-label input {
position: absolute;
opacity: 0;
cursor: pointer;
height: 0;
width: 0;
}
.checkmark {
position: absolute;
top: 15px;
left: 15px;
height: 25px;
width: 25px;
border-radius: 3px;
background-color: #eee;
}
.checkmark:after {
content: '';
position: absolute;
display: none;
left: 9px;
top: 5px;
width: 5px;
height: 10px;
border: solid white;
border-width: 0 3px 3px 0;
transform: rotate(45deg);
}
.check-label:hover input ~ .checkmark {
background-color: #ccc;
}
.check-label input:checked ~ .checkmark {
background-color: #2196F3;
}
.check-label input:checked ~ .checkmark:after {
display: block;
}