:root {
    --bg-color: #1a1a1a;
    --container-bg: rgba(43, 43, 43, 0.8);
    --text-primary: #ffffff;
    --text-secondary: #aaaaaa;
    --shadow-color: rgba(0, 0, 0, 0.5);
    --border-color: rgba(255, 255, 255, 0.1);
    --btn-gradient: linear-gradient(135deg, #00d2ff 0%, #3a7bd5 100%);
    --btn-shadow: rgba(58, 123, 213, 0.4);
}

[data-theme="light"] {
    --bg-color: #f0f2f5;
    --container-bg: rgba(255, 255, 255, 0.9);
    --text-primary: #1a1a1a;
    --text-secondary: #555555;
    --shadow-color: rgba(0, 0, 0, 0.1);
    --border-color: rgba(0, 0, 0, 0.1);
    --btn-gradient: linear-gradient(135deg, #3a7bd5 0%, #00d2ff 100%);
    --btn-shadow: rgba(0, 210, 255, 0.2);
}

[data-theme="red"] {
    --bg-color: #1a0000;
    --container-bg: rgba(60, 10, 10, 0.85);
    --text-primary: #ffffff;
    --text-secondary: #ffaaaa;
    --shadow-color: rgba(200, 0, 0, 0.5);
    --border-color: rgba(255, 100, 100, 0.2);
    --btn-gradient: linear-gradient(135deg, #ff4444 0%, #cc0000 100%);
    --btn-shadow: rgba(255, 68, 68, 0.4);
}

body {
    font-family: 'Pretendard', -apple-system, BlinkMacSystemFont, system-ui, Roboto, 'Helvetica Neue', 'Segoe UI', 'Apple SD Gothic Neo', 'Noto Sans KR', 'Malgun Gothic', sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    margin: 0;
    background-color: var(--bg-color);
    background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 200 200' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='noiseFilter'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.65' numOctaves='3' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23noiseFilter)'/%3E%3C/svg%3E");
    background-blend-mode: overlay;
    color: var(--text-primary);
    overflow-x: hidden;
    transition: background-color 0.3s ease, color 0.3s ease;
}

.container {
    position: relative;
    text-align: center;
    padding: 60px 40px;
    background-color: var(--container-bg);
    border-radius: 40px;
    box-shadow: 0 30px 60px var(--shadow-color);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border: 1px solid var(--border-color);
    max-width: 90%;
    width: 600px;
    margin: 20px;
    transition: background-color 0.3s ease, box-shadow 0.3s ease, border 0.3s ease;
}

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

#theme-btn {
    background: none;
    border: 1px solid var(--border-color);
    border-radius: 50%;
    width: 40px;
    height: 40px;
    cursor: pointer;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 20px;
    transition: all 0.3s ease;
    color: var(--text-primary);
}

#theme-btn:hover {
    background-color: var(--border-color);
    transform: rotate(15deg);
}

h1 {
    margin-bottom: 50px;
    font-size: 2.5em;
    font-weight: 800;
    letter-spacing: -1px;
    background: linear-gradient(to bottom, var(--text-primary), var(--text-secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    text-shadow: 0 10px 20px rgba(0, 0, 0, 0.1);
}

.lotto-numbers-container {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 15px;
    margin-bottom: 50px;
    min-height: 80px;
}

#generate-btn {
    padding: 20px 50px;
    font-size: 20px;
    font-weight: 700;
    cursor: pointer;
    border: none;
    border-radius: 100px;
    background: var(--btn-gradient);
    color: white;
    box-shadow: 0 10px 25px var(--btn-shadow);
    transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    text-transform: uppercase;
    letter-spacing: 2px;
    position: relative;
    overflow: hidden;
}

#generate-btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
    transition: 0.5s;
}

#generate-btn:hover::before {
    left: 100%;
}

#generate-btn:hover {
    transform: translateY(-5px) scale(1.02);
    box-shadow: 0 20px 40px var(--btn-shadow);
}

#generate-btn:active {
    transform: translateY(-2px) scale(0.98);
}

lotto-ball {
    width: 60px;
    height: 60px;
}

.contact-container {
    margin-top: 20px;
}

.contact-container h2 {
    font-size: 1.8em;
    font-weight: 800;
    margin-bottom: 30px;
    background: linear-gradient(to bottom, var(--text-primary), var(--text-secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: 6px;
    margin-bottom: 18px;
    text-align: left;
}

.form-group label {
    font-size: 0.9em;
    font-weight: 600;
    color: var(--text-secondary);
}

.form-group input,
.form-group textarea {
    background: var(--border-color);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 12px 16px;
    font-size: 1em;
    color: var(--text-primary);
    outline: none;
    transition: border 0.2s ease, box-shadow 0.2s ease;
    font-family: inherit;
    resize: vertical;
}

.form-group input::placeholder,
.form-group textarea::placeholder {
    color: var(--text-secondary);
    opacity: 0.6;
}

.form-group input:focus,
.form-group textarea:focus {
    border-color: rgba(255, 255, 255, 0.3);
    box-shadow: 0 0 0 3px var(--btn-shadow);
}

.submit-btn {
    width: 100%;
    padding: 16px;
    font-size: 1em;
    font-weight: 700;
    cursor: pointer;
    border: none;
    border-radius: 100px;
    background: var(--btn-gradient);
    color: white;
    box-shadow: 0 10px 25px var(--btn-shadow);
    transition: all 0.3s ease;
    letter-spacing: 1px;
    margin-top: 8px;
}

.submit-btn:hover {
    transform: translateY(-3px);
    box-shadow: 0 15px 35px var(--btn-shadow);
}

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

.form-success {
    margin-top: 16px;
    color: #69c8a0;
    font-weight: 600;
    font-size: 0.95em;
}

@media (max-width: 480px) {
    .container {
        padding: 40px 20px;
    }
    h1 {
        font-size: 1.8em;
    }
    lotto-ball {
        width: 50px;
        height: 50px;
    }
}