:root {
    --primary-color: #4a90e2;
    --bg-color: #f5f7fa;
    --card-bg: #ffffff;
    --text-color: #333;
    --sub-text-color: #666;
    --shadow-color: rgba(0, 0, 0, 0.05);
    
    /* Lotto Ball Colors */
    --ball-1: #fbc400; /* 1-10 */
    --ball-11: #69c8f2; /* 11-20 */
    --ball-21: #ff7272; /* 21-30 */
    --ball-31: #aaa;    /* 31-40 */
    --ball-41: #b0d840; /* 41-45 */
}

[data-theme='dark'] {
    --bg-color: #1a1a1a;
    --card-bg: #2d2d2d;
    --text-color: #f0f0f0;
    --sub-text-color: #aaa;
    --shadow-color: rgba(0, 0, 0, 0.3);
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: 'Pretendard', -apple-system, BlinkMacSystemFont, system-ui, Roboto, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    display: flex;
    justify-content: center;
    padding: 40px 20px;
    min-height: 100vh;
    transition: background-color 0.3s, color 0.3s;
}

.container {
    max-width: 600px;
    width: 100%;
    text-align: center;
    position: relative;
}

.theme-toggle {
    position: absolute;
    top: -20px;
    right: 0;
}

#theme-btn {
    background: var(--card-bg);
    border: 1px solid var(--shadow-color);
    color: var(--text-color);
    padding: 8px 12px;
    border-radius: 20px;
    cursor: pointer;
    font-size: 0.9rem;
    display: flex;
    align-items: center;
    gap: 5px;
    transition: all 0.3s;
    box-shadow: 0 2px 5px var(--shadow-color);
}

header p {
    color: var(--sub-text-color);
}

.lotto-set {
    background: var(--card-bg);
    padding: 20px;
    border-radius: 15px;
    display: flex;
    justify-content: center;
    gap: 10px;
    box-shadow: 0 2px 10px var(--shadow-color);
    animation: fadeIn 0.5s ease forwards;
    transition: background-color 0.3s, box-shadow 0.3s;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

.ball {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-weight: bold;
    font-size: 0.9rem;
    text-shadow: 0 1px 2px rgba(0,0,0,0.2);
    box-shadow: inset -3px -3px 6px rgba(0,0,0,0.1), 3px 3px 6px rgba(0,0,0,0.1);
}

.ball.range-1 { background-color: var(--ball-1); }
.ball.range-11 { background-color: var(--ball-11); }
.ball.range-21 { background-color: var(--ball-21); }
.ball.range-31 { background-color: var(--ball-31); }
.ball.range-41 { background-color: var(--ball-41); }

@media (max-width: 480px) {
    .ball {
        width: 35px;
        height: 35px;
        font-size: 0.8rem;
    }
}