html,
body {
    margin: 0;
    padding: 0;
    height: 100%;
    width: 100%;
    font-family: sans-serif;
    background: #f0f0f0;
}

/* Container for initial buttons */
.button-container {
    display: flex;
    flex-direction: column;
    align-items: center;
    height: 100vh;
    justify-content: center;
}

/* Custom timers container */
.custom-timers {
    display: flex;
    flex-direction: row;
    flex-wrap: wrap;
    justify-content: center;
    margin: 20px;
    align-items: center;
}

.custom-timers button.start-timer {
    margin: 10px;
    padding: 20px 40px;
    font-size: 1.5rem;
    cursor: pointer;
    position: relative;
}

/* Each individual timer item */
.custom-timer-item {
    display: flex;
    flex-direction: column;
    align-items: center;
}

/* Remove timer button */
.custom-timer-item button.remove-timer {
    font-size: 1.2rem;
    cursor: pointer;
    border: none;
    background: transparent;
    opacity: 30%;
    font-weight: bold;
}

/* Add timer form */
.add-timer-form {
    display: flex;
    margin-top: 20px;
}

.add-timer-form input {
    padding: 10px;
    font-size: 1rem;
    margin-right: 10px;
    width: 100px;
    text-align: center;
}

.add-timer-form button {
    padding: 10px 20px;
    font-size: 1rem;
    cursor: pointer;
}

/* Fullscreen countdown display */
.countdown-display {
    display: none;
    justify-content: center;
    align-items: center;
    background: #000;
    color: #fff;
    font-size: 15vw;
    font-weight: bold;
    height: 100vh;
    width: 100vw;
    text-align: center;
    position: relative;
}

/* Flash animation when done */
@keyframes flash {
    0% {
        background: #000;
        color: #fff;
    }
    50% {
        background: #fff;
        color: #000;
    }
    100% {
        background: #000;
        color: #fff;
    }
}

.flash {
    animation: flash 0.5s alternate infinite;
}

/* Cancel (X) button */
.cancel-btn {
    position: absolute;
    top: 10px;
    left: 10px;
    font-size: 3rem;
    font-weight: bold;
    color: #fff;
    background: transparent;
    border: none;
    cursor: pointer;
    display: none;
}