:root {
    --background-color: #f0f0f0;
    --text-color: #333;
    --card-background: white;
    --button-background: #4CAF50;
    --button-text-color: white;
    --number-background: #eee;
    --shadow-color: rgba(0, 0, 0, 0.1);
}

.dark-mode {
    --background-color: #333;
    --text-color: #f0f0f0;
    --card-background: #444;
    --button-background: #5cb85c;
    --number-background: #555;
    --shadow-color: rgba(255, 255, 255, 0.1);
}

html, body {
    height: 100%;
    margin: 0;
}

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

header {
    display: flex;
    justify-content: flex-end;
    padding: 1rem;
}

#theme-toggle {
    background-color: var(--button-background);
    color: var(--button-text-color);
    padding: 0.5rem 1rem;
    border: none;
    border-radius: 0.5rem;
    cursor: pointer;
}

main {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 80vh;
}

lotto-generator {
    display: block;
    padding: 2rem;
    background-color: var(--card-background);
    color: var(--text-color); /* Ensure text color is inherited */
    border-radius: 1rem;
    box-shadow: 0 10px 25px var(--shadow-color);
    text-align: center;
    transition: background-color 0.3s, color 0.3s, box-shadow 0.3s;
}

.lotto-numbers {
    display: flex;
    flex-direction: column; /* Changed to column to stack sets */
    align-items: center;
    gap: 1.5rem; /* Space between sets */
    margin-bottom: 2rem;
}

.lotto-set {
    display: flex;
    justify-content: center;
    gap: 1rem;
    padding: 1rem;
    border: 1px solid var(--number-background); /* Subtle border for each set */
    border-radius: 0.5rem;
    background-color: var(--card-background); /* Use card background for set */
    box-shadow: 0 2px 5px var(--shadow-color);
}


.lotto-number {
    width: 3rem;
    height: 3rem;
    border-radius: 50%;
    background-color: var(--number-background);
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--text-color);
}

button {
    background-color: var(--button-background);
    color: var(--button-text-color);
    padding: 1rem 2rem;
    border: none;
    border-radius: 0.5rem;
    font-size: 1rem;
    cursor: pointer;
    transition: background-color 0.3s;
}

button:hover {
    opacity: 0.9;
}