style.css

html, body {
  margin: 0px;
  font: 15px/160% Calibri, "Helvetica Neue", Arial, sans-serif;
}

#content {
  max-width: 800px;
  margin: auto;
}

header {
  padding: 80px 30px 40px 20px;
  background: #1a1a1a;
  color: #3ab5d4;
  text-shadow: 0 1px 0 #000;
  font-style: italic;
  -webkit-font-smoothing: antialiased;
}

header #title {
  max-width: 800px;
  margin: auto;
}

#timer {
  background-color: #9b7ca5;
  color: white;
  padding: 38px 40px;
  margin: 10px;
  display: inline-block;
  font-weight: 600;
  -webkit-border-radius: 100px;
}

#time-left {
  font-size: 50px;
  width: 60px;
  text-align: right;
  margin: 10px 0 0 0;
}

#time-left-sec {
  float: right;
  margin: 5px -5px 0px 0px;
}

button {
  position: relative;
  overflow: visible;
  display: inline-block;
  padding: 0.5em 1em;
  border: 1px solid #d4d4d4;
  margin: 0 3px;
  margin-left: 15px;
  text-decoration: none;
  text-shadow: 1px 1px 0 #fff;
  font: 11px/normal sans-serif;
  color: #333;
  white-space: nowrap;
  cursor: pointer;
  outline: none;
  background-color: #ececec;
  -webkit-border-radius: 3px;
}

button:hover,
button:focus,
button:active {
  border-color: #3072b3;
  border-bottom-color: #2a65a0;
  text-decoration: none;
  text-shadow: -1px -1px 0 rgba(0,0,0,0.3);
  color: #fff;
  background-color: #3C8DDE;
  background-image: -webkit-gradient(linear, 0 0, 0 100%, from(#599bdc), to(#3072b3));
  background-image: -moz-linear-gradient(#599bdc, #3072b3);
  background-image: -o-linear-gradient(#599bdc, #3072b3);
  background-image: linear-gradient(#599bdc, #3072b3);
}

button:active {
  border-color: #2a65a0;
  border-bottom-color: #3884CF;
  background-color: #3072b3;
  background-image: -webkit-gradient(linear, 0 0, 0 100%, from(#3072b3), to(#599bdc));
  background-image: -moz-linear-gradient(#3072b3, #599bdc);
  background-image: -o-linear-gradient(#3072b3, #599bdc);
  background-image: linear-gradient(#3072b3, #599bdc);
}