:root {
    --bg-gradient: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
    --container-bg: rgba(255, 255, 255, 0.1);
    --text-primary: #333;
    --text-secondary: #555;
    --footer-text: #888;
    --container-shadow: 0 20px 40px rgba(0, 0, 0, 0.2), 0 0 0 2px rgba(255, 255, 255, 0.3);
    --container-border: rgba(255, 255, 255, 0.2);
    --svg-opacity: 0.3;
    --svg-stroke: rgba(0,0,0,0.05);
}

[data-theme='dark'] {
    --bg-gradient: linear-gradient(135deg, #1a1a2e 0%, #16213e 100%);
    --container-bg: rgba(0, 0, 0, 0.3);
    --text-primary: #e0e0e0;
    --text-secondary: #b0b0b0;
    --footer-text: #777;
    --container-shadow: 0 20px 40px rgba(0, 0, 0, 0.5), 0 0 0 2px rgba(255, 255, 255, 0.05);
    --container-border: rgba(255, 255, 255, 0.1);
    --svg-opacity: 0.1;
    --svg-stroke: rgba(255,255,255,0.1);
}

body {
    font-family: 'Pretendard', sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    margin: 0;
    background: var(--bg-gradient);
    overflow: hidden;
    position: relative;
    transition: background 0.3s ease;
}

body::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-image: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" width="100" height="100" viewBox="0 0 100 100"><rect width="100" height="100" fill="none"/><path d="M0 50 Q 50 0, 100 50 T 200 50" stroke="rgba(0,0,0,0.05)" stroke-width="1" fill="none"/><path d="M50 100 Q 0 50, 50 0 T 50 -100" stroke="rgba(0,0,0,0.05)" stroke-width="1" fill="none"/></svg>');
    opacity: var(--svg-opacity);
    z-index: -1;
    transition: opacity 0.3s ease;
}

.container {
    text-align: center;
    background: var(--container-bg);
    padding: 40px 60px;
    border-radius: 20px;
    box-shadow: var(--container-shadow);
    backdrop-filter: blur(10px);
    border: 1px solid var(--container-border);
    max-width: 600px;
    width: 90%;
    transition: all 0.3s ease;
}

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

#theme-btn {
    background: var(--container-bg);
    border: 1px solid var(--container-border);
    color: var(--text-primary);
    padding: 10px;
    border-radius: 50%;
    cursor: pointer;
    font-size: 1.2rem;
    transition: all 0.3s ease;
    width: 45px;
    height: 45px;
    display: flex;
    justify-content: center;
    align-items: center;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
}

h1 {
    font-size: 2.5rem;
    font-weight: 900;
    color: var(--text-primary);
    margin-bottom: 10px;
    text-shadow: 0 2px 4px rgba(0,0,0,0.1);
    transition: color 0.3s ease;
}

p {
    color: var(--text-secondary);
    font-size: 1.1rem;
    transition: color 0.3s ease;
}

.lotto-numbers {
    display: flex;
    justify-content: center;
    gap: 15px;
    margin: 40px 0;
    flex-wrap: wrap;
}

.lotto-number {
    display: flex;
    justify-content: center;
    align-items: center;
    width: 70px;
    height: 70px;
    border-radius: 50%;
    color: white;
    font-size: 1.8rem;
    font-weight: bold;
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.15);
    transition: all 0.3s ease;
    transform: translateY(20px);
    opacity: 0;
    animation: appear 0.5s forwards;
}

@keyframes appear {
    to {
        transform: translateY(0);
        opacity: 1;
    }
}

#generate-btn {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border: none;
    padding: 18px 40px;
    font-size: 1.2rem;
    font-weight: bold;
    border-radius: 50px;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 8px 15px rgba(0, 0, 0, 0.2);
}

#generate-btn:hover {
    transform: translateY(-3px);
    box-shadow: 0 12px 20px rgba(0, 0, 0, 0.3);
}

#generate-btn:active {
    transform: translateY(1px);
    box-shadow: 0 5px 10px rgba(0, 0, 0, 0.2);
}

.contact-section {
    margin-top: 50px;
    padding-top: 30px;
    border-top: 1px solid var(--container-border);
}

.comment-section {
    margin-top: 50px;
    padding-top: 30px;
    border-top: 1px solid var(--container-border);
    text-align: left;
}

.contact-section h2 {
    color: var(--text-primary);
    margin-bottom: 20px;
    font-size: 1.5rem;
}

#contact-form {
    display: flex;
    flex-direction: column;
    gap: 15px;
    max-width: 400px;
    margin: 0 auto;
}

.form-group {
    text-align: left;
}

.form-group input, 
.form-group textarea {
    width: 100%;
    padding: 12px 15px;
    border-radius: 10px;
    border: 1px solid var(--container-border);
    background: var(--container-bg);
    color: var(--text-primary);
    font-family: inherit;
    font-size: 0.95rem;
    box-sizing: border-box;
    transition: all 0.3s ease;
}

.form-group textarea {
    height: 100px;
    resize: vertical;
}

.form-group input:focus, 
.form-group textarea:focus {
    outline: none;
    border-color: #667eea;
    box-shadow: 0 0 0 2px rgba(102, 126, 234, 0.2);
}

#submit-btn {
    background: linear-gradient(135deg, #43e97b 0%, #38f9d7 100%);
    color: #2c3e50;
    border: none;
    padding: 12px 25px;
    font-size: 1rem;
    font-weight: bold;
    border-radius: 50px;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.1);
    margin-top: 10px;
}

#submit-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 15px rgba(0, 0, 0, 0.2);
}

footer p {
    font-size: 0.9rem;
    color: var(--footer-text);
    margin-top: 30px;
    transition: color 0.3s ease;
}