body {
  margin: 0;
  padding: 0;
  min-height: 100vh;
  background-color: black;
  display: flex;
  align-items: center;
  justify-content: center;
}

#fs-frm input,
#fs-frm select,
#fs-frm textarea,
#fs-frm fieldset,
#fs-frm optgroup,
#fs-frm label,
#fs-frm #card-element:disabled {
  box-sizing: border-box; 
  font-family: inherit;
  font-size: 100%;
  color: inherit;
  border: none;
  border-radius: 0;
  display: block;
  width: calc(min(100vw - 16px, 600px));
  padding: 0;
  margin: 0;
  -webkit-appearance: none;
  -moz-appearance: none;
}
#fs-frm label,
#fs-frm legend,
#fs-frm ::placeholder {
  font-size: .825rem;
  margin-bottom: .5rem;
  padding-top: .2rem;
  display: flex;
  align-items: baseline;
}

/* border, padding, margin, width */
#fs-frm input,
#fs-frm select,
#fs-frm textarea {
  border: 1px solid rgba(0,0,0,0.2);
  background-color: rgba(255,255,255,0.9);
  padding: .75em 1rem;
  margin-bottom: 1.5rem;
}
#fs-frm input:focus,
#fs-frm select:focus,
#fs-frm textarea:focus {
  background-color: white;
  outline-style: solid;
  outline-width: thin;
  outline-color: gray;
  outline-offset: -1px;
}

#fs-frm [type="button"],
#fs-frm [type="submit"],
#fs-frm [type="reset"] {
  width: auto;
  cursor: pointer;
  -webkit-appearance: button;
  -moz-appearance: button;
  appearance: button;
}

#fs-frm [type="button"][disabled],
#fs-frm [type="submit"][disabled]
{
  cursor: progress;
  color: #888;
}

#fs-frm [type="button"]:focus,
#fs-frm [type="submit"]:focus,
#fs-frm [type="reset"]:focus {
  outline: none;
}
#fs-frm [type="submit"],
#fs-frm [type="reset"] {
  margin-bottom: 0;
}