:root {
    --bg-color: #f8f9fa;
    --container-bg: #ffffff;
    --text-color: #212529;
    --accent-color: #4CAF50;
    --ball-bg: #e9ecef;
    --ball-text: #212529;
    --shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    --bonus-color: #ff9800;
}

[data-theme="dark"] {
    --bg-color: #121212;
    --container-bg: #1e1e1e;
    --text-color: #f8f9fa;
    --accent-color: #66bb6a;
    --ball-bg: #333333;
    --ball-text: #f8f9fa;
    --shadow: 0 10px 30px rgba(0, 0, 0, 0.5);
}

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

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

.container {
    text-align: center;
    padding: 3rem;
    background-color: var(--container-bg);
    border-radius: 24px;
    box-shadow: var(--shadow);
    width: 90%;
    max-width: 600px;
    position: relative;
    transition: background-color 0.3s ease, box-shadow 0.3s ease;
}

.theme-toggle {
    position: absolute;
    top: 20px;
    right: 20px;
    background: none;
    border: none;
    cursor: pointer;
    font-size: 1.5rem;
    color: var(--text-color);
    transition: transform 0.3s ease;
}

.theme-toggle:hover {
    transform: rotate(20deg);
}

h1 {
    margin-bottom: 2rem;
    font-size: 2.5rem;
    font-weight: 800;
    letter-spacing: -0.02em;
}

.numbers-wrapper {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1.5rem;
    margin-bottom: 3rem;
}

.numbers-container, .bonus-container {
    display: flex;
    justify-content: center;
    gap: 12px;
}

.section-label {
    font-size: 0.9rem;
    font-weight: 600;
    text-transform: uppercase;
    opacity: 0.6;
    margin-bottom: 0.5rem;
}

.number {
    width: 60px;
    height: 60px;
    border-radius: 50%;
    background-color: var(--ball-bg);
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--ball-text);
    box-shadow: 0 4px 6px rgba(0,0,0,0.05);
    animation: popIn 0.5s cubic-bezier(0.175, 0.885, 0.32, 1.275) both;
}

.number.bonus {
    background-color: var(--bonus-color);
    color: white;
}

@keyframes popIn {
    0% { transform: scale(0); opacity: 0; }
    100% { transform: scale(1); opacity: 1; }
}

#generate-btn {
    padding: 1rem 2.5rem;
    border: none;
    background-color: var(--accent-color);
    color: white;
    border-radius: 12px;
    font-size: 1.25rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
}

#generate-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(0, 0, 0, 0.15);
    filter: brightness(1.1);
}

#generate-btn:active {
    transform: translateY(0);
}

.divider {
    width: 40px;
    height: 2px;
    background-color: var(--ball-bg);
    align-self: center;
    margin: 0 10px;
}

@media (max-width: 600px) {
    .container { padding: 2rem 1.5rem; }
    h1 { font-size: 1.8rem; }
    .number { width: 45px; height: 45px; font-size: 1.2rem; }
    .numbers-container { gap: 8px; }
}