:root {
    --background-color: #f8f9fa;
    --container-bg: #ffffff;
    --text-color: #212529;
    --text-muted: #6c757d;
    --main-accent-color: #4a90e2;
    --secondary-accent-color: #50e3c2;
    --white: #ffffff;
    --shadow-color: rgba(0, 0, 0, 0.08);
    --machine-bg: linear-gradient(145deg, #e9ecef, #ffffff);
    --grid-color: #e9ecef;
    --header-bg: rgba(255, 255, 255, 0.9);
    --footer-bg: #343a40;
}

[data-theme='dark'] {
    --background-color: #121212;
    --container-bg: #1e1e1e;
    --text-color: #f8f9fa;
    --text-muted: #adb5bd;
    --main-accent-color: #64b5f6;
    --secondary-accent-color: #81c784;
    --shadow-color: rgba(0, 0, 0, 0.4);
    --machine-bg: linear-gradient(145deg, #2c2c2c, #1e1e1e);
    --grid-color: #1a1a1a;
    --header-bg: rgba(30, 30, 30, 0.9);
}

* {
    box-sizing: border-box;
    scroll-behavior: smooth;
}

body {
    font-family: 'Pretendard', -apple-system, BlinkMacSystemFont, system-ui, Roboto, 'Helvetica Neue', Arial, sans-serif;
    background-color: var(--background-color);
    color: var(--text-color);
    margin: 0;
    line-height: 1.6;
    transition: background-color 0.3s ease, color 0.3s ease;
}

.container, .container-inner {
    max-width: 800px;
    margin: 0 auto;
    padding: 4rem 1.5rem;
}

.container-inner {
    padding: 0 1.5rem;
}

/* Header & Nav */
.main-header {
    position: fixed;
    top: 0;
    width: 100%;
    background: var(--header-bg);
    backdrop-filter: blur(10px);
    z-index: 1000;
    box-shadow: 0 2px 10px var(--shadow-color);
}

.nav-container {
    max-width: 1000px;
    margin: 0 auto;
    padding: 1rem 1.5rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--main-accent-color);
    letter-spacing: -1px;
}

.nav-links {
    list-style: none;
    display: flex;
    gap: 1.5rem;
    margin: 0;
}

.nav-links a {
    text-decoration: none;
    color: var(--text-color);
    font-weight: 500;
    font-size: 0.95rem;
    transition: color 0.3s;
}

.nav-links a:hover {
    color: var(--main-accent-color);
}

/* Main Content */
.content-wrapper {
    padding-top: 80px;
}

h1 {
    font-size: 2.5rem;
    margin-bottom: 0.5rem;
    color: var(--main-accent-color);
}

.subtitle {
    color: var(--text-muted);
    margin-bottom: 2rem;
}

.lotto-machine {
    background: var(--machine-bg);
    border-radius: 20px;
    padding: 3rem;
    margin-bottom: 2.5rem;
    box-shadow: inset 0 2px 15px var(--shadow-color);
}

.number-display {
    display: flex;
    justify-content: center;
    gap: 1rem;
    flex-wrap: wrap;
    min-height: 80px;
}

.lotto-ball {
    width: 60px;
    height: 60px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    font-weight: 700;
    color: white;
    box-shadow: 0 5px 15px rgba(0,0,0,0.15);
    animation: popIn 0.5s cubic-bezier(0.175, 0.885, 0.32, 1.275) forwards;
}

#generate-btn {
    background: var(--main-accent-color);
    color: white;
    border: none;
    padding: 1.2rem 3rem;
    font-size: 1.25rem;
    font-weight: 700;
    border-radius: 50px;
    cursor: pointer;
    box-shadow: 0 10px 20px -5px var(--main-accent-color);
    transition: transform 0.2s, box-shadow 0.2s;
}

#generate-btn:hover {
    transform: translateY(-3px);
    box-shadow: 0 15px 25px -5px var(--main-accent-color);
}

/* Info Sections */
.info-section {
    padding: 5rem 0;
}

.bg-alt {
    background-color: var(--grid-color);
}

h2 {
    font-size: 2rem;
    margin-bottom: 1.5rem;
    color: var(--main-accent-color);
}

.feature-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
    margin-top: 3rem;
}

.feature-card {
    background: var(--container-bg);
    padding: 2rem;
    border-radius: 15px;
    box-shadow: 0 5px 15px var(--shadow-color);
}

.feature-card h3 {
    margin-top: 0;
    color: var(--secondary-accent-color);
}

.tip-list {
    text-align: left;
    max-width: 600px;
    margin: 2rem auto;
}

.tip-list li {
    margin-bottom: 1rem;
}

/* Form Styles */
.contact-section {
    background: var(--container-bg);
    padding: 3rem;
    border-radius: 20px;
    box-shadow: 0 10px 30px var(--shadow-color);
}

.contact-form {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
    text-align: left;
    margin-top: 2rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 600;
}

.form-group input, .form-group textarea {
    width: 100%;
    padding: 1rem;
    border: 1px solid var(--grid-color);
    border-radius: 10px;
    background: var(--background-color);
    color: var(--text-color);
    font-family: inherit;
}

#submit-btn {
    background: var(--secondary-accent-color);
    color: white;
    border: none;
    padding: 1rem;
    border-radius: 10px;
    font-weight: 700;
    cursor: pointer;
}

/* Footer */
.main-footer {
    background: var(--footer-bg);
    color: #ced4da;
    padding: 3rem 0;
    text-align: center;
}

.footer-links {
    margin-top: 1rem;
    display: flex;
    justify-content: center;
    gap: 2rem;
}

.footer-links a {
    color: #adb5bd;
    text-decoration: none;
    font-size: 0.9rem;
}

.footer-links a:hover {
    color: white;
}

#theme-btn {
    background: none;
    border: 1px solid var(--main-accent-color);
    color: var(--main-accent-color);
    padding: 0.5rem;
    border-radius: 50%;
    cursor: pointer;
    width: 36px;
    height: 36px;
    display: flex;
    align-items: center;
    justify-content: center;
}

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

@media (max-width: 600px) {
    .nav-links { display: none; }
    h1 { font-size: 2rem; }
    .feature-grid { grid-template-columns: 1fr; }
    .lotto-machine { padding: 1.5rem; }
}