:root {
    --background-color-light: #f0f0f0;
    --text-color-light: #333;
    --container-bg-light: #fff;
    --button-bg-light: #4CAF50;
    --button-text-light: white;

    --background-color-dark: #333;
    --text-color-dark: #f0f0f0;
    --container-bg-dark: #424242;
    --button-bg-dark: #5cb85c;
    --button-text-dark: white;
}

body {
    font-family: sans-serif;
    transition: background-color 0.3s, color 0.3s;
}

body.light-mode {
    background-color: var(--background-color-light);
    color: var(--text-color-light);
}

body.dark-mode {
    background-color: var(--background-color-dark);
    color: var(--text-color-dark);
}

.container {
    max-width: 500px;
    margin: 50px auto;
    padding: 20px;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    transition: background-color 0.3s;
}

body.light-mode .container {
    background-color: var(--container-bg-light);
}

body.dark-mode .container {
    background-color: var(--container-bg-dark);
}

h1 {
    text-align: center;
}

#generate {
    display: block;
    width: 100%;
    padding: 10px;
    border: none;
    border-radius: 4px;
    font-size: 16px;
    cursor: pointer;
    margin-bottom: 20px;
    transition: background-color 0.3s;
}

body.light-mode #generate {
    background-color: var(--button-bg-light);
    color: var(--button-text-light);
}

body.dark-mode #generate {
    background-color: var(--button-bg-dark);
    color: var(--button-text-dark);
}

#numbers-container {
    display: grid;
    gap: 10px;
}

.number-set {
    display: flex;
    justify-content: center;
    gap: 10px;
    padding: 10px;
    background-color: #f9f9f9;
    border-radius: 4px;
}

body.dark-mode .number-set {
    background-color: #555;
}



.circle-number {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    display: flex;
    justify-content: center;
    align-items: center;
    background-color: #007bff; /* A nice blue for the circles */
    color: white;
    font-weight: bold;
    font-size: 18px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.2);
}

body.dark-mode .circle-number {
    background-color: #1a73e8; /* Slightly different blue for dark mode */
}


.theme-switcher {
    display: flex;
    align-items: center;
    justify-content: flex-end;
    margin-top: 20px;
}

.switch {
    position: relative;
    display: inline-block;
    width: 60px;
    height: 34px;
    margin-left: 10px;
}

.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%;
}