:root {
    --bg-gradient: radial-gradient(circle, #1a1a2e 0%, #16213e 100%);
    --container-bg: rgba(255, 255, 255, 0.05);
    --text-color: #ffffff;
    --placeholder-color: rgba(255, 255, 255, 0.4);
    --border-color: rgba(255, 255, 255, 0.18);
    --shadow-color: rgba(0, 0, 0, 0.37);
    --btn-bg: linear-gradient(45deg, #ff4757, #ff6b81);
}

[data-theme="light"] {
    --bg-gradient: radial-gradient(circle, #f0f2f5 0%, #c9d6ff 100%);
    --container-bg: rgba(255, 255, 255, 0.8);
    --text-color: #2f3542;
    --placeholder-color: rgba(47, 53, 66, 0.4);
    --border-color: rgba(0, 0, 0, 0.1);
    --shadow-color: rgba(0, 0, 0, 0.1);
    --btn-bg: linear-gradient(45deg, #3742fa, #5352ed);
}

body {
    margin: 0;
    padding: 0;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background: var(--bg-gradient);
    font-family: 'Pretendard', -apple-system, BlinkMacSystemFont, system-ui, Roboto, sans-serif;
    color: var(--text-color);
    transition: background 0.3s ease, color 0.3s ease;
}

.container {
    position: relative;
    text-align: center;
    background: var(--container-bg);
    padding: 3rem;
    border-radius: 2rem;
    box-shadow: 0 8px 32px 0 var(--shadow-color);
    backdrop-filter: blur(4px);
    border: 1px solid var(--border-color);
    transition: background 0.3s ease, box-shadow 0.3s ease;
}

.theme-toggle {
    position: absolute;
    top: 1rem;
    right: 1rem;
}

#theme-btn {
    background: none;
    border: 1px solid var(--border-color);
    border-radius: 50%;
    width: 40px;
    height: 40px;
    font-size: 1.2rem;
    cursor: pointer;
    display: flex;
    justify-content: center;
    align-items: center;
    transition: transform 0.2s ease, background 0.2s ease;
    color: var(--text-color);
}

#theme-btn:hover {
    transform: rotate(15deg) scale(1.1);
    background: rgba(255, 255, 255, 0.1);
}

h1 {
    margin-bottom: 2rem;
    font-size: 2.5rem;
    text-shadow: 0 0 10px var(--placeholder-color);
}

.lotto-container {
    display: flex;
    justify-content: center;
    gap: 15px;
    min-height: 100px;
    margin-bottom: 2.5rem;
    flex-wrap: wrap;
}

.placeholder {
    font-size: 1.2rem;
    color: var(--placeholder-color);
    line-height: 100px;
}

/* 로또 공 스타일 */
.ball {
    width: 60px;
    height: 60px;
    border-radius: 50%;
    display: flex;
    justify-content: center;
    align-items: center;
    font-weight: bold;
    font-size: 1.5rem;
    color: white;
    text-shadow: 1px 1px 2px rgba(0,0,0,0.5);
    box-shadow: inset -5px -5px 10px rgba(0,0,0,0.3), 3px 3px 10px rgba(0,0,0,0.3);
    animation: popIn 0.5s cubic-bezier(0.175, 0.885, 0.32, 1.275) both;
}

@keyframes popIn {
    0% { transform: scale(0) rotate(-180deg); opacity: 0; }
    100% { transform: scale(1) rotate(0); opacity: 1; }
}

/* 번호별 색상 */
.ball.yellow { background: radial-gradient(circle at 30% 30%, #fbc531, #e1b12c); }
.ball.blue { background: radial-gradient(circle at 30% 30%, #487eb0, #40739e); }
.ball.red { background: radial-gradient(circle at 30% 30%, #e84118, #c23616); }
.ball.gray { background: radial-gradient(circle at 30% 30%, #7f8c8d, #718093); }
.ball.green { background: radial-gradient(circle at 30% 30%, #4cd137, #44bd32); }

/* 버튼 스타일 */
.generate-btn {
    padding: 1rem 2.5rem;
    font-size: 1.2rem;
    font-weight: bold;
    color: white;
    background: var(--btn-bg);
    border: none;
    border-radius: 50px;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px var(--shadow-color);
    outline: none;
}


.generate-btn:hover {
    transform: translateY(-3px) scale(1.05);
    box-shadow: 0 6px 20px rgba(255, 71, 87, 0.6);
}

.generate-btn:active {
    transform: translateY(-1px);
}