box-sizing.css

html,
body,
div,
article,
aside,
section,
main,
nav,
footer,
header,
form,
fieldset,
legend,
pre,
code,
p,
a,
h1,
h2,
h3,
h4,
h5,
h6,
ul,
ol,
li,
dl,
dt,
dd,
blockquote,
figcaption,
figure,
textarea,
input[type='email'],
input[type='number'],
input[type='password'],
input[type='tel'],
input[type='text'],
input[type='url'],
.border-box {
  box-sizing: border-box;
}