.container {
    display: flex;
    align-items: center;
    flex-direction: column;
    justify-content: space-between;
}

header {
    position: static;
    left: 0;
    top: 0;
    background-color: whitesmoke;
    text-align: center;
    width: 100%;
}

header>p {
    padding-left: 0.1em;
    padding-right: 0.1em;
}

main {
    text-align: center;
    flex: 1 1 auto;
}

footer {
    position: static;
    width: 100%;
    background-color: whitesmoke;
    text-align: center;
    font-size: small;
    margin-top: 15px;
    bottom: 0;
    left: 0;
    right: 0;
}


#hours,
#minutes {
    border-style: solid;
    font-size: 4em;
    padding-left: 10px;
    padding-right: 10px;
    box-sizing: border-box;
    margin: 1.5vw;

}

#timerButtons {
    margin-top: 25px;
    font-family: 'Courier New', Courier, monospace;
}

h2 {
    font-size: 200%;
}

button {
    color: white;
    border: none;
    padding: 15px 32px;
    text-align: center;
    text-decoration: none;
    display: inline-block;
    font-size: 1em;
}

.btn-primary {
    border: 2px solid black;
    background-color: rgb(36, 101, 241);
    color: white;
    font-size: 16px;
    cursor: pointer;
}

.btn-secondary {
    border: 2px solid black;
    background-color: white;
    color: black;
    font-size: 16px;
    cursor: pointer;
}

button:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

.interval {
    margin-top: 50px;
}

#btnStart, #btnStop {
    margin-right: 20px;
}

@media screen and (max-width: 768px) {
    /* For mobile phones */
    #timerButtons button {
        width: 100%;
        margin-bottom: 5px;
    }
}