html/index.css
html {
  font-family: 'Source Sans Pro', 'Helvetica', 'Arial', sans-serif;
  font-size: 62.5%;
  -ms-text-size-adjust: 100%;
  -webkit-text-size-adjust: 100%;
}

body {
  background-color: #F5F5F5;

  font-size: 1.5em;
  line-height: 1.6;
  font-weight: 400;
  color: #121212;

  margin: 0;
}

header {
  text-align: center;
  margin: 4.2rem 0;
}

header h1 {
  color: #666;
}

footer {
  font-size: 1.3rem;
  font-weight: 300;
  color: #B6B6B6;
  margin: 5.4rem 0;
  text-align: center;
  display: flex;
  flex-flow: column;
}
footer a {
  color: #777777;
  text-decoration: none;
}

h1 {
  font-size: 9.6rem;
  font-weight: 300;
  line-height: 7.2rem;
}

h4 {
  font-size: 2.0rem;
  font-weight: normal;
}

h1, h2, h3, h4, h5, h6 {
  margin: 0.3rem 0 0.9rem;
}

.Container {
  margin: 0 auto;

  display: flex;
  flex-flow: row;
}

.AppContainer {
  background-color: #FFFFFF;

  border-radius: 3px;
  margin: 1.5rem;
  padding: 1.2rem 1.5rem 1.45rem 1.5rem;
  height: 100%;

  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.12), 0 1px 2px rgba(0, 0, 0, 0.24);

  flex: 1;
  display: flex;
  flex-flow: column;
}

.App {
  margin-top: 0.9rem;
  flex: 1;
  display: flex;
  flex-flow: column;
}

.App input[type="text"] {
  font-size: 1.4rem;
  border: none;
  border-bottom: 1px solid #121212;
  padding: 0.3rem 0.1rem;
  outline: none;
  flex: 1;
}
.App input[type="text"]:focus {
  border-bottom: 1px solid #2050F9;
}
.App input[type="text"]::placeholder {
  font-style: italic;
  color: #A5A5A5;
}

.App small {
  color: #666;
  text-align: right;
}


.Tasks {
  padding: 1.2rem 0 0.9rem;

  flex-flow: row;
  align-items: flex-start;
}

.Task {
  font-size: 1.6rem;
  border-bottom: 1px dotted #A5A5A5;
  padding: 0.6rem 0 0.3rem;
  margin: 0.6rem 0 0.9rem;
  display: flex;
  align-items: center;
}

.Task span {
  margin-right: 0.9rem;
  flex: 1;
}
.Task span:hover { cursor: pointer; }
.Task.done span {
  color: #A5A5A5;
  text-decoration: line-through;
}

.Task button {
  background-color: #F0F0F0;
  font-size: 1.6rem;
  color: #666;

  border: none;
  border-radius: 50%;
  outline: none;

  line-height: 1.3rem;
  padding: 0;
  width: 2.1rem;
  height: 2.1rem;
}
.Task button:hover {
  background-color: #FFD6D6;
  cursor: pointer;
}
