html, body, a, p, h1, h2, h3, h4, h5, h6, li, ul, ol, dl, dt, dd, div, section, article, header, main, footer, span, u, s, aside, input, button, table, thead, tbody, tr, td {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  height: 100%;
}

body {
  font-size: 62.5%;
  font-family: "Hiragino Kaku Gothic Pro", Meiryo, "MS PGothic", sans-serif;
}

.mail_box {
  text-align: center;
}

.mail_box .crimson {
  color: #ed143d;
}

.mail_box-title {
  font-size: 1rem;
}

.mail_box-subtitle {
  font-size: 1rem;
  display: flex;
  justify-content: space-between;
  align-items: baseline;
}

.mail_box-subtitle:nth-of-type(3) {
  margin-bottom: 30px;
}

.mail_box input[type="email"],
.mail_box input[type="text"] {
  width: 100%;
  max-width: 215px;
  padding: 12px 10px;
  font-size: 1rem;
  letter-spacing: 1px;
  border: 1px solid #ced4da;
  border-radius: 5px;
  margin-bottom: 10px;
}

.mail_box textarea {
  height: 75pt;
  width: 100%;
  border: 1px solid #ced4da;
  padding-left: 5px;
  font: 400 1rem Arial;
}

.mail_box button {
  color: #fff;
  border: 0;
  padding: 10px;
  font-size: 1rem;
  cursor: pointer;
}

.mail_box button[type="button"],
.mail_box button[type="submit"] {
  font-weight: bold;
  margin-bottom: 20px;
  border-radius: 15px;
  border: 5px solid #000;
  box-shadow: #000 0 10px;
  background-color: #2d9cd8;
  width: 230px;
  display: inline-block;
  padding: 20px 0;
}

.mail_box button[type="button"]:hover,
.mail_box button[type="submit"]:hover {
  position: relative;
  box-shadow: none;
  top: 10px;
}