:root {
    --bg-color: #f8f9fa;
    --text-color: #333;
    --card-bg: white;
    --shadow: rgba(0, 0, 0, 0.1);
    --btn-bg: #1a73e8;
    --btn-hover: #1557b0;
}

/* 다크 모드 변수 */
body.dark-mode {
    --bg-color: #121212;
    --text-color: #f1f1f1;
    --card-bg: #1e1e1e;
    --shadow: rgba(0, 0, 0, 0.5);
    --btn-bg: #37474f;
    --btn-hover: #455a64;
}

body {
    font-family: 'Pretendard', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
    background-color: var(--bg-color);
    color: var(--text-color);
    transition: background-color 0.3s, color 0.3s;
}

.theme-btn {
    position: absolute;
    top: 20px;
    right: 20px;
    background: none;
    border: 2px solid var(--text-color);
    color: var(--text-color);
    font-size: 1.5rem;
    cursor: pointer;
    padding: 5px 10px;
    border-radius: 12px;
    transition: all 0.3s;
}

#app {
    text-align: center;
    padding: 3rem;
    background: var(--card-bg);
    border-radius: 20px;
    box-shadow: 0 10px 30px var(--shadow);
    transition: background-color 0.3s, box-shadow 0.3s;
}

h1 {
    margin-bottom: 2rem;
}

#lotto-container {
    display: flex;
    justify-content: center;
    gap: 15px;
    margin-bottom: 2rem;
    min-height: 60px;
}

.ball {
    width: 50px;
    height: 50px;
    border-radius: 50%;
    display: flex;
    justify-content: center;
    align-items: center;
    color: white;
    font-weight: bold;
    font-size: 1.2rem;
    box-shadow: 2px 2px 5px rgba(0,0,0,0.2);
    animation: bounce 0.5s ease;
}

.ball-yellow { background-color: #fbc400; }
.ball-blue { background-color: #69c8f2; }
.ball-red { background-color: #ff7272; }
.ball-gray { background-color: #aaa; }
.ball-green { background-color: #b0d840; }

#generate-btn {
    padding: 12px 24px;
    font-size: 1.1rem;
    background-color: var(--btn-bg);
    color: white;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    transition: background 0.3s, transform 0.1s;
}

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

#generate-btn:active {
    transform: scale(0.95);
}

@keyframes bounce {
    0% { transform: scale(0); }
    70% { transform: scale(1.1); }
    100% { transform: scale(1); }
}