styles.css

* { margin: 0; padding: 0; font-family: Arial, sans-serif; }
.contentWrapper {
    display: flex; flex-direction: column; justify-content: center;
    align-items: center; width: 100%; height: 100vh; background-color: #006466;
}
.top {
  display: flex; justify-content: center; align-items: center; flex-direction: row;
  background: #fff; color: #c1121f; padding: 1rem 0; width: 700px;
}
#container {
    height: 300px; width: 700px; background-color: #fff; margin: 0 auto;
    display: flex; justify-content: space-around; align-items: center;
}
#container > div { display: flex; flex-direction: column; }
.label {
    align-self: center; justify-self: center; color: #c1121f;
    text-align: center; font-size: 30px; font-weight: bold;
}
.timer { 
    display: flex; align-self: center; justify-self: center; justify-content: center;
    font-size: 30px; font-weight: bold; padding: 1rem 0;
}
p { margin: 0; padding: 0; }
.btn {
    padding: 1rem 2rem; font-size: 20px; color: #fff;
    background: #c1121f; border: none; border-radius: 25px;
    cursor: pointer; transition: background .7s;
}
.btn:hover { background: #780000; }