:root {
    --bg-color: #f0f2f5;
    --container-bg: #fff;
    --text-color: #333;
    --btn-bg: #007bff;
    --btn-hover: #0056b3;
    --lotto-bg: #4CAF50;
    --lotto-text: #fff;
    --shadow-color: rgba(0, 0, 0, 0.1);
}

body.dark-mode {
    --bg-color: #1a1a1a;
    --container-bg: #2d2d2d;
    --text-color: #f0f0f0;
    --btn-bg: #3498db;
    --btn-hover: #2980b9;
    --lotto-bg: #27ae60;
    --lotto-text: #fff;
    --shadow-color: rgba(0, 0, 0, 0.5);
}

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

.container {
    background-color: var(--container-bg);
    padding: 40px;
    border-radius: 15px;
    box-shadow: 0 10px 20px var(--shadow-color);
    text-align: center;
    position: relative;
    transition: background-color 0.3s, box-shadow 0.3s;
}

h1 {
    color: var(--text-color);
    margin-bottom: 30px;
}

.lotto-numbers {
    display: flex;
    justify-content: center;
    gap: 15px;
    margin-bottom: 30px;
    min-height: 50px;
}

.lotto-number {
    width: 50px;
    height: 50px;
    border-radius: 50%;
    background-color: var(--lotto-bg);
    color: var(--lotto-text);
    font-size: 24px;
    font-weight: bold;
    display: flex;
    justify-content: center;
    align-items: center;
    animation: fadeIn 0.5s ease-in-out;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: scale(0.8);
    }
    to {
        opacity: 1;
        transform: scale(1);
    }
}

.controls {
    display: flex;
    flex-direction: column;
    gap: 15px;
}

#generate-btn {
    background-color: var(--btn-bg);
    color: #fff;
    border: none;
    padding: 15px 30px;
    border-radius: 8px;
    font-size: 18px;
    cursor: pointer;
    transition: background-color 0.3s;
}

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

#theme-toggle {
    background: none;
    border: 1px solid var(--text-color);
    color: var(--text-color);
    padding: 8px 16px;
    border-radius: 20px;
    cursor: pointer;
    font-size: 14px;
    align-self: flex-end;
    margin-bottom: 10px;
    transition: all 0.3s;
}

#theme-toggle:hover {
    background-color: var(--text-color);
    color: var(--container-bg);
}