style.css

body {
    background: url("https://static.pexels.com/photos/6663/desk-white-black-header.jpg") no-repeat center center fixed;
    /* background: url("backbg.jpg") no-repeat center center fixed; */
    background-size: cover; 
}
.pomodoro {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 500px;  
    padding-top: 15px;
    padding-bottom: 25px;  
}
p {
    text-align: center;
}
.flip-clock-wrapper {
    max-width: 460px;
    margin: 3em auto 2em;
    display: flex;
    justify-content: center;
}
.col-md-4 {
    display: flex;
    justify-content: center;
}
.col-md-4 #session, .col-md-4 #break {
    display: flex;
    justify-content: center;
    height: 34px;
    align-items: center;
}
.counter {
    display: flex;
    justify-content: center;
    gap: 10px;
}
.clock {
    margin-top: 30px;
}
.container {
    width: 500px;
}
.middle {
    display: inline-block;
}
#btns {
    display: flex;
    justify-content: center;
    gap: 10px;
}
.btn {
    background-color: #333333;
    color: #CCCCCC;
    border-radius: 5px;
    transition: background-color 0.3s, color 0.3s;
    border: none;
    padding: 10px 20px;
    font-size: 16px;
}
.btn:hover {
    background-color: #FFFFFF;
    color: #333333;
}
#sessInc, #sessDec, #breakInc, #breakDec {  
    font-weight: bold;
}
#stats {
    background-color: #333333;
    width: 220px;
    height: 70px;  
    border-radius: 10px;
    color: #CCCCCC;
    font-size: 45px;
    text-align: center;
}
#statRow {
    display: flex;
    justify-content: center;
    margin-bottom: 20px;
}

/* FlipClock styles override */
.flip-clock-wrapper ul {
    background: none;
    box-shadow: none;
}

.flip-clock-wrapper ul li a div div.inn, 
.flip-clock-wrapper ul li a div div.inn:before, 
.flip-clock-wrapper ul li a div div.inn:after {
    background-color: #333;
    border: none;
}

.flip-clock-wrapper ul li a div div.inn {
    box-shadow: none;
}

.flip-clock-wrapper ul li a div.up:after {
    top: 0;
    height: 100%;
}

.flip-clock-wrapper ul li a div.down:after {
    bottom: 0;
    height: 100%;
}