simple-notes/style.css

/* Mobile first design */
html {
  font-family: sans-serif;
}

body {
  max-width: 100%;
}
header, footer {
  background-color: green;
  color: white;
  padding: 0 20px;
}
header {
  line-height: 80px;
}
footer {
  font-size: 10pt;
}
form div {
  display: grid;
  grid-template-columns: 1fr 4fr;
  grid-template-rows: repeat(3, auto);
  justify-content: space-evenly;
}
/* long spacious button */
#newBtn {
  grid-column: 2/5;
}
form div label {
  text-align: right;
  margin-right: 1em;
}
.new-note, .note-display {
  padding: 20px;
}
.new-note {
  background: lightgreen;
}

h1 {
  margin: 0;
}

ul {
  list-style-type: none;
}

div {
  margin-bottom: 10px;
}

/* For wider display */
@media (min-width: 600px) {
  body {
    margin: 0 auto;
    max-width: 800px;
  }
}