body {
    font-family: sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background-color: #f0f0f0;
    transition: background-color 0.3s ease;
}

body.dark {
    background-color: #1a1a1a;
    color: #fff;
}

#app {
    text-align: center;
}

#numbers span {
    display: inline-block;
    width: 50px;
    height: 50px;
    line-height: 50px;
    border-radius: 50%;
    margin: 10px;
    font-size: 24px;
    font-weight: bold;
    color: #fff;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.2);
    border: 2px solid #fff;
}


/* Theme Switch */
.theme-switch-wrapper {
    position: absolute;
    top: 20px;
    right: 20px;
}

.theme-switch {
    position: relative;
    display: inline-block;
    width: 60px;
    height: 34px;
}

.theme-switch input {
    opacity: 0;
    width: 0;
    height: 0;
}

.slider {
    position: absolute;
    cursor: pointer;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: #ccc;
    transition: .4s;
}

.slider:before {
    position: absolute;
    content: "";
    height: 26px;
    width: 26px;
    left: 4px;
    bottom: 4px;
    background-color: white;
    transition: .4s;
}

input:checked + .slider {
    background-color: #2196F3;
}

input:focus + .slider {
    box-shadow: 0 0 1px #2196F3;
}

input:checked + .slider:before {
    transform: translateX(26px);
}

.slider.round {
    border-radius: 34px;
}

.slider.round:before {
    border-radius: 50%;
}