style.css

* {
    font-family: "Archivo", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen-Sans, Ubuntu, Cantarell, "Helvetica Neue", Helvetica, Arial, sans-serif;
}

html, body {
    height: 100%;
    margin: 0;
}

#page {
    height: 100%;
    background-color: #066bb6;
    transition: background-color 0.2s;
    display: flex;
    align-items: center;
    flex-direction: column;
    user-select: none;
}

header {
    position: relative;
    top: 0;
    line-height: 0;
    width: 100%;
    background-color: rgba(206, 30, 165, 0.15);
    font-size: 3rem;
    font-weight: bold;
    text-align: center;
    border-bottom: 1px solid rgba(255, 255, 255, 0.6);
    color: white;
    letter-spacing: 0.5px;
}

#start, #reset, #finish, #early {
    position: relative;
    top: 120px;
    line-height: 70px;
    width: 250px;
    background-color: rgba(218, 162, 205, 0.25);
    font-size: 2.5rem;
    font-weight: bold;
    text-align: center;
    cursor: pointer;
    border-radius: 5px;
    border: 1px solid rgba(255, 255, 255, 0.5);
    color: white;
    letter-spacing: 0.5px;
}

#reset {
    margin-top: 20px;
    display: none;
}

#finish {
    display: none;
}

#early {
    display: none;
    width: 300px;
    font-size: 2rem;
    line-height: 50px;
}

.information {
    background-color: rgba(218, 162, 205, 0.25);
    position: relative;
    top: 140px;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-direction: column;
    color: white;
    font-size: 1.5rem;
    border-radius: 10px;
    border: 1px solid rgba(255, 255, 255, 0.5);
}

.form {
    margin-top: 20px;
    width: 400px;
    height: 250px;
    /*display: none;*/
}

.congratulations {
    height: 125px;
    width: 400px;
    margin-top: 20px;
    display: none;
}

.stats {
    position: relative;
    width: 480px;
    height: 480px;
    justify-content: flex-start;
    display: none;
}

.stats p:first-child {
    position: relative;
    top: -25px;
    width: 100%;
    margin-bottom: 0;
    line-height: 48px;
    text-align: center;
    border-bottom: 1px solid rgba(255, 255, 255, 0.5);
}

.lists {
    display: flex;
    justify-content: center;
}

.lists ul {
    list-style-type: none;
}

.lists ul li {
    margin-top: 14px;
    font-size: 1.1rem;
    padding-bottom: 2px;
    border-bottom: 1px solid rgba(255, 255, 255, 0.4);
}

.lists ul hr {
    margin-top: -2px;
}

.lists ul:first-child {
    padding: 39px 30px 25px;
    margin: 0 15px 0 0;
    border-right: 1px solid rgba(255, 255, 255, 0.9);
}

.lists ul:first-child li {
    text-align: right;
}

.lists ul:last-child {
    margin: 0 30px 0 0;
    padding: 0 15px;
}

.lists ul:last-child li{
    text-align: center;
}

.lists ul:last-child li:first-child {
    margin-left: 3px;
    letter-spacing: 1px;
    border: none;
}

#msg {
    width: 401px;
    background-color: rgba(255, 255, 255, 0.07);
    border-top: 2px solid rgba(255, 255, 255, 0.5);
    border-bottom: 2px solid rgba(255, 255, 255, 0.5);
}

#msg p{
    margin: 0;
    font-size: 3rem;
    line-height: 70px;
    font-size: 2.5rem;
    font-weight: bold;
    letter-spacing: 0.5px;
    text-align: center;
}

#required {
    background-color: rgba(250, 140, 224, 0.3);
    position: relative;
    top: -35px;
    left: 130px;
    width: 90px;
    padding: 0 6px 0 18px;
    height: 95px;
    color: white;
    font-size: 1rem;
    border-radius: 10px;
    border: 1px solid rgba(255, 255, 255, 0.5);
    opacity: 0;
    transition: opacity 0.5s;
}

input {
    width: 72px;
    line-height: 20px;
    border-radius: 2px;
    margin: 5px 0 10px;
    border: 1px solid rgba(255, 255, 255, 1);
    letter-spacing: 1px;
}

input:focus {
    outline: none;
}

#action {
    position: relative;
    top: 100px;
    right: 50px;
    background-color: rgba(218, 162, 205, 0.25);
    border-radius: 5px;
    border: 1px solid rgba(255, 255, 255, 0.5);
    width: 300px;
    height: 50px;
    margin-top: 20px;
    transition: all 0.15s;
    display: none;
}

#action p {
    margin: 0;
    line-height: 50px;
    text-align: center;
    font-size: 2rem;
    font-weight: 500;
    color: white;
}

#sets {
    position: relative;
    top: 48px;
    left: 160px;
    background-color: rgba(218, 162, 205, 0.25);
    border-radius: 5px;
    border: 1px solid rgba(255, 255, 255, 0.5);
    width: 80px;
    height: 50px;
    transition: all 0.15s;
    display: none;
}

#sets p {
    margin: 0;
    line-height: 50px;
    text-align: center;
    font-size: 2rem;
    font-weight: 500;
    color: white;
}

#timer {
    position: relative;
    top: 70px;
    width: 400px;
    height: 150px;
    background-color: rgba(218, 162, 205, 0.25);
    border-radius: 5px;
    border: 1px solid rgba(255, 255, 255, 0.5);
    transition: all 0.15s;
    display: none;
}

#timer p {
    margin: 0;
    line-height: 150px;
    text-align: center;
    font-size: 6rem;
    font-weight: 500;
    color: white;
}

#exercise {
    position: relative;
    top: 90px;
    background-color: rgba(218, 162, 205, 0.25);
    border-radius: 5px;
    border: 1px solid rgba(255, 255, 255, 0.5);
    width: 400px;
    height: 50px;
    transition: all 0.15s;
    display: none;
}

#exercise p {
    margin: 0;
    line-height: 50px;
    text-align: center;
    font-size: 1.5rem;
    font-weight: 500;
    color: white;
}