body {
  margin: 0;
  background: #163a50;
  font: 300 100%/120% "Tahoma", Arial, Helvetica, sans-serif;
}

header {
  overflow: hidden;
}

header, nav, .contents, footer {
  box-sizing: border-box;
  max-width: 1080px;
  margin-left: auto;
  margin-right: auto;
}

header, nav, footer {
  background: #0f2736;
}

h1, h2, h3, h4 {
  font-weight: bold
}

.contents {
  padding: 1em 2em 2.5em 2em;
}

/* increase line spacing for main title */
h1 {
  line-height: 120%;
  margin-top: 0.5em;
  float: left;
  width: auto;
}

header img {
  float: left;
}

/* change color and remove underline for links */
footer a {
  color: inherit;
  text-decoration: none;
}

#plan_table a {
  color: rgb(0, 47, 255);
}

/* size and margin for logo image */
header img {
  max-width: 100%;
  max-height: 100%;
  margin: 0.5em;
}

form {
  padding: 1em 2em;
}

input[type="number"] {
  min-width: 4em;
}

/* style for footer */
footer {
  margin: auto;
  text-align: center;
}

footer div {
  padding: 1em;
}

.contents h2 {
  text-align: center;
}

button {
  margin-top: 1em;
  margin-bottom: 1em;
  width: 5em;
  height: 2em;
}

input {
  width: 5em;
  height: 1.6em;
  margin-right: 2em;
}

#delete_div p{
  color: gray;
}


header *, nav * {
  color: #FFFFFF;
}

.contents {
  background: #FFFFFF;
}

.subtitle {
  font-size: 0.6em;
  font-weight: normal;
}

@media screen and (max-width: 1080px) {
  header,nav {
      overflow: hidden;
  }
}

@media screen and (max-width: 720px) {
  header img {
      display: none;
  }
  header h1 {
      padding: 0 0.5em;
  }
  nav div {
      width: 100%;
  }
}

.contents {
  text-align: center;
}

.contents li{
  text-align: left;
}

/* style for the table */
table, th, td {
  border: 1.8px solid black;
  border-collapse: collapse;
  text-align: center;
  vertical-align: center;
  margin: auto;
  width: 400px;
  height: 50px;
}

th {
  background-color: rgb(178, 177, 177);
}

.highlight {
  background-color: rgb(255, 0, 0);
}

#plan_table {
  margin-bottom: 2em;
}