table {
    border-collapse: collapse;
    margin: 1em auto;
}

 th, td {
  padding: 0.3em;
  text-align: left;
  /* border-bottom: 1px solid #ddd; */
}

* {
    font-family: arial;
}

caption {
    font-size: 1.2em;
}

.controls {
    margin-bottom: 1em;
}

button.selected {
    background-color: palegreen;
}

#startBtn {
    margin-left: 2em;
    background-color: orange;
}

tbody {
    border-bottom: 3px solid gainsboro;
}

tr {
    border-bottom: 1px solid gainsboro;
}

h1 {
    margin-bottom: 0.2em;
    font-size: 1.2em;
}

.header {
    text-align: center;
}

a {
    text-decoration: none;
}