/* GLOBAL RESET */
* {
  box-sizing: border-box;
}

html, body {
  margin: 0;
  padding: 0;
  width: 100%;
  height: 100%;
}

/* FIXED HEADER SAFE OFFSET */
header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 64px;
  z-index: 1000;
}

/* CRITICAL FIX: prevents header overlap */
main {
  padding-top: 80px;
  min-height: 100vh;
  display: block;
}