style.css

@import url('https://fonts.googleapis.com/css2?family=Poppins:ital,wght@0,100;0,200;0,300;0,400;0,500;0,600;0,700;0,800;0,900;1,100;1,200;1,300;1,400;1,500;1,600;1,700;1,800;1,900&display=swap');

*{
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family:'Poppins', sans-serif;
    
}
body{
    background:#2b3239;
    
}
.container,.button,.controls{
    display: flex;
    justify-content: center;
    align-items: center;
    text-align: center;
    border-radius: 40px;

}
.container{
    margin-top: 100px;
    flex-direction: column;
}


.result h4{
    font-size: 1.6rem;
    margin-bottom: 20px;
}
.result{
    font-size: 3rem;
    color: #1d2630;
    background: #fff;
    padding: 30px 10px;
    border-radius: 20px;
    margin-bottom: 20px;
    padding: 40px;
}

.result span{
    width: 3rem;
}

.button button{
    justify-content: center;
    align-items: center;
    margin: 0.5rem;
    border: none;
    outline: none;
    height: 43px;
    width: 100px;
    color: #1d2630;
    font-weight: bold ;
    font-size:1.1rem ;
    border-radius: 5px;
    cursor: pointer;
}
.button button:hover{
    background-color: #dfe0e0;
}

.container2 {
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: #fff;
    flex-direction: column;
    width: 40%;
    margin-top: 4%;
    margin-left: 30%;
    padding: 30px;
    border-radius: 10px;
}
.container2 h2{
    margin-bottom: 20px;
    font-size: 1.7rem;
}
.container2 h1{
    font-size: 2.4rem;
    font-weight: 500;
    display: flex;
    justify-content: center;
    align-items: center;
    padding-left: 18px;
}
.timerbtns{
    display: flex;
    justify-content: center;
    align-items: center;
    flex-direction: row;
    gap: 20px;
    margin-top: 20px;
}
.timerbtns button{
    padding:7px 18px;
    border: none;
    border-radius: 7px;
    background-color:#1d2630;
    color: white;
    font-size: 2rem;
    font-weight: 600;
}
#startbtn,#stopbtn,#custombtn,#resetbtn{
    cursor: pointer;
}

#startbtn:hover,#stopbtn:hover,#custombtn:hover,#resetbtn:hover{
    background-color:#343435;
}

button span{
    align-content: center;
    justify-content: center;
}

@media only screen and (max-width:425px) {
    .container2{
        width: 80%;
        margin-left: 12%;
    }
    .timerbtns{
        gap:15px;
    }
}