:root {
    --bg-color: #f0f0f0;
    --container-bg: #ffffff;
    --text-color: #333333;
    --number-bg: #eeeeee;
    --number-text: #333333;
    --btn-bg: #4CAF50;
    --btn-hover: #45a049;
    --shadow: rgba(0, 0, 0, 0.1);
}

body.dark-mode {
    --bg-color: #1a1a1a;
    --container-bg: #2d2d2d;
    --text-color: #f0f0f0;
    --number-bg: #444444;
    --number-text: #ffffff;
    --shadow: rgba(0, 0, 0, 0.5);
}

body {
    font-family: sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    margin: 0;
    transition: background-color 0.3s, color 0.3s;
}

.container {
    background-color: var(--container-bg);
    padding: 2rem;
    border-radius: 10px;
    box-shadow: 0 0 10px var(--shadow);
    text-align: center;
    position: relative;
    width: 90%;
    max-width: 400px;
}

.theme-toggle-btn {
    position: absolute;
    top: 1rem;
    right: 1rem;
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    padding: 0.5rem;
    border-radius: 50%;
    transition: background-color 0.3s;
}

.theme-toggle-btn:hover {
    background-color: var(--number-bg);
}

h1 {
    margin-bottom: 2rem;
}

.lotto-display {
    display: flex;
    justify-content: center;
    margin-bottom: 2rem;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.lotto-number {
    font-size: 1.5rem;
    font-weight: bold;
    width: 50px;
    height: 50px;
    border-radius: 50%;
    background-color: var(--number-bg);
    color: var(--number-text);
    display: flex;
    justify-content: center;
    align-items: center;
    transition: background-color 0.3s, color 0.3s;
}

#generate-btn {
    background-color: var(--btn-bg);
    color: white;
    padding: 1rem 2rem;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    font-size: 1rem;
    margin-bottom: 2rem;
    transition: background-color 0.3s;
}

#generate-btn:hover {
    background-color: var(--btn-hover);
}

.history {
    text-align: left;
}

#history-list {
    list-style: none;
    padding: 0;
    max-height: 150px;
    overflow-y: auto;
}

#history-list li {
    padding: 0.5rem 0;
    border-bottom: 1px solid var(--number-bg);
}