html, body {
  height: 100%;
}

body {
  padding: 0;
}

/*
A3 is 297 x 420

default print is Portrait
height = 420
width = 297

margin left = 4 cm
=> margin-right = 4 cm
=> width of art is 217 mm

=> margin top is : (420 - 217) / 2 = 101.5

*/

/*
// vertical centered
@page {
  size: A3;
  margin-left: 4cm;
  margin-right: 4cm;
  margin-top: 10.15cm;
}
*/

/*
A3 is 297 x 420
Landscape:
  height = 297
  width = 420

  margin top and bottom = 2 cm
  art size is 297 - 40 = 257

  margin left = 2 cm
  margin right = 420 - 257 - 20 = 143
*/
@page {
  size: A3;
  size: landscape;
  margin-top: 20mm;
  margin-bottom: 20mm;
  margin-left: 20mm;
  margin-right: 143mm;
}