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

body {
    font-family: 'Open Sans', sans-serif;
    background: #ecf0f1;
    color: #2c3e50;
    line-height: 1.7;
}

.section-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Header */
.site-header {
    background: linear-gradient(135deg, #2C3E50 0%, #34495E 100%);
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
    position: sticky;
    top: 0;
    z-index: 999;
}

.header-wrapper {
    max-width: 1200px;
    margin: 0 auto;
    padding: 1.2rem 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.site-logo {
    display: flex;
    align-items: center;
    gap: 15px;
}

.logo-name {
    color: white;
    font-size: 2rem;
    font-weight: 800;
    letter-spacing: 1px;
}

.mobile-nav-btn {
    display: none;
    background: none;
    border: none;
    flex-direction: column;
    gap: 5px;
    cursor: pointer;
}

.mobile-nav-btn span {
    width: 30px;
    height: 3px;
    background: white;
    transition: 0.3s;
}

.site-navigation {
    display: flex;
    gap: 2.5rem;
}

.nav-link {
    color: white;
    text-decoration: none;
    font-weight: 600;
    font-size: 1.05rem;
    transition: color 0.3s ease;
    position: relative;
}

.nav-link:hover {
    color: #34A8E0;
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background: #34A8E0;
    transition: width 0.3s ease;
}

.nav-link:hover::after {
    width: 100%;
}

/* Hero Section */
.hero-section {
    background: linear-gradient(135deg, #2C3E50 0%, #34495E 50%, #2C3E50 100%);
    padding: 5rem 2rem;
    text-align: center;
    color: white;
}

.hero-container h1 {
    font-size: 3.8rem;
    font-weight: 800;
    margin-bottom: 1.5rem;
}

.hero-description {
    font-size: 1.5rem;
    font-weight: 300;
}

/* Key Features */
.key-features {
    padding: 5rem 0;
    background: white;
}

.features-row {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 2rem;
}

.feature-box {
    padding: 3rem 2rem;
    border-radius: 15px;
    color: white;
    box-shadow: 0 10px 35px rgba(0, 0, 0, 0.15);
    transition: transform 0.3s ease;
}

.feature-box:hover {
    transform: translateY(-8px);
}

.feature-box.blue {
    background: linear-gradient(135deg, #3498DB 0%, #2980B9 100%);
}

.feature-box.navy {
    background: linear-gradient(135deg, #2C3E50 0%, #34495E 100%);
}

.feature-box.dark {
    background: linear-gradient(135deg, #1A252F 0%, #2C3E50 100%);
}

.feature-symbol {
    font-size: 3.5rem;
    margin-bottom: 1.5rem;
}

.feature-box h3 {
    font-size: 1.8rem;
    margin-bottom: 1rem;
    font-weight: 700;
}

.feature-box p {
    font-size: 1.1rem;
    line-height: 1.7;
}

/* Introduction Section */
.introduction-section {
    padding: 5rem 0;
    background: #f8f9fa;
}

.intro-layout {
    display: grid;
    grid-template-columns: 1.5fr 1fr;
    gap: 4rem;
    align-items: center;
}

.intro-content h2 {
    color: #2C3E50;
    font-size: 3rem;
    margin-bottom: 2rem;
    font-weight: 800;
}

.intro-content p {
    font-size: 1.15rem;
    margin-bottom: 1.5rem;
    color: #555;
    line-height: 1.8;
}

.intro-visual {
    display: flex;
    justify-content: center;
    align-items: center;
}

.visual-element {
    width: 350px;
    height: 350px;
    background: linear-gradient(135deg, #D6EAF8 0%, #AED6F1 100%);
    border-radius: 50%;
    display: flex;
    justify-content: center;
    align-items: center;
    box-shadow: 0 15px 50px rgba(44, 62, 80, 0.2);
}

/* Game Section */
.game-section {
    padding: 5rem 0;
    background: white;
}

.section-title {
    text-align: center;
    color: #2C3E50;
    font-size: 3rem;
    margin-bottom: 1rem;
    font-weight: 800;
}

.section-subtitle {
    text-align: center;
    font-size: 1.3rem;
    color: #666;
    margin-bottom: 3rem;
}

.game-container {
    background: #1a1a1a;
    padding: 2.5rem;
    border-radius: 20px;
    box-shadow: 0 15px 50px rgba(0, 0, 0, 0.2);
}

.game-container iframe {
    width: 100%;
    height: 650px;
    border: none;
    border-radius: 10px;
}

/* Advantages Section */
.advantages-section {
    padding: 5rem 0;
    background: #f8f9fa;
}

.advantages-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
}

.advantage-item {
    background: white;
    padding: 2.5rem 2rem;
    border-radius: 15px;
    text-align: center;
    box-shadow: 0 8px 30px rgba(0, 0, 0, 0.08);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.advantage-item:hover {
    transform: translateY(-8px);
    box-shadow: 0 15px 40px rgba(44, 62, 80, 0.15);
}

.advantage-emoji {
    font-size: 3.5rem;
    display: block;
    margin-bottom: 1.5rem;
}

.advantage-item h4 {
    color: #2C3E50;
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
}

.advantage-item p {
    color: #666;
    font-size: 1.05rem;
}

/* Responsibility Section */
.responsibility-section {
    padding: 5rem 0;
    background: white;
}

.responsibility-content {
    background: linear-gradient(135deg, #D6EAF8 0%, #AED6F1 100%);
    padding: 3.5rem;
    border-radius: 20px;
    border-left: 8px solid #2C3E50;
    max-width: 900px;
    margin: 0 auto;
}

.responsibility-content h2 {
    color: #2C3E50;
    font-size: 2.5rem;
    font-weight: 800;
    margin-bottom: 1.5rem;
}

.responsibility-content p {
    font-size: 1.15rem;
    color: #34495E;
    line-height: 1.8;
    margin-bottom: 1.5rem;
}

/* Play Page */
.play-header {
    background: linear-gradient(135deg, #2C3E50 0%, #34495E 100%);
    padding: 4rem 2rem;
    text-align: center;
    color: white;
}

.play-header h1 {
    font-size: 3.5rem;
    font-weight: 800;
    margin-bottom: 1rem;
}

.game-guide {
    padding: 4rem 0;
    background: white;
}

.game-guide h2 {
    color: #2C3E50;
    font-size: 2.5rem;
    font-weight: 800;
    text-align: center;
    margin-bottom: 3rem;
}

.guide-items {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 2rem;
}

.guide-item {
    background: #f8f9fa;
    padding: 2.5rem;
    border-radius: 15px;
    text-align: center;
    border: 2px solid #D6EAF8;
}

.guide-icon {
    font-size: 3rem;
    display: block;
    margin-bottom: 1rem;
}

.guide-item h4 {
    color: #2C3E50;
    font-size: 1.4rem;
    font-weight: 700;
    margin-bottom: 1rem;
}

.play-area-section {
    padding: 4rem 0;
    background: #f8f9fa;
}

.play-game-container {
    background: #1a1a1a;
    padding: 2.5rem;
    border-radius: 20px;
    box-shadow: 0 15px 50px rgba(0, 0, 0, 0.2);
    margin-bottom: 2rem;
}

.play-game-container iframe {
    width: 100%;
    height: 700px;
    border: none;
    border-radius: 10px;
}

.play-notice {
    background: white;
    padding: 2rem;
    border-radius: 15px;
    text-align: center;
    border: 3px solid #2C3E50;
}

.play-notice strong {
    color: #2C3E50;
}

/* Legal Page */
.legal-page {
    padding: 5rem 0;
    background: white;
}

.legal-page h1 {
    color: #2C3E50;
    font-size: 3.5rem;
    font-weight: 800;
    margin-bottom: 1rem;
}

.legal-page h2 {
    color: #34495E;
    font-size: 2rem;
    font-weight: 700;
    margin-top: 2.5rem;
    margin-bottom: 1rem;
}

.legal-page p, .legal-page li {
    font-size: 1.05rem;
    color: #555;
    margin-bottom: 1rem;
    line-height: 1.8;
}

.legal-page ul {
    margin-left: 2rem;
    margin-bottom: 1.5rem;
}

.legal-date {
    color: #999;
    font-style: italic;
    margin-bottom: 2.5rem;
}

.important-notice {
    background: linear-gradient(135deg, #EBF5FB 0%, #D6EAF8 100%);
    padding: 2.5rem;
    border-radius: 15px;
    margin: 2.5rem 0;
    border-left: 8px solid #2C3E50;
}

.important-notice h2 {
    margin-top: 0;
    color: #2C3E50;
}

/* Footer */
.site-footer {
    background: #1A252F;
    color: #bbb;
    padding: 3.5rem 0 1.5rem;
}

.footer-layout {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 3rem;
    margin-bottom: 2.5rem;
}

.footer-segment h4 {
    color: #34A8E0;
    font-size: 1.4rem;
    font-weight: 800;
    margin-bottom: 1rem;
}

.footer-segment ul {
    list-style: none;
}

.footer-segment li {
    margin-bottom: 0.7rem;
}

.footer-segment a {
    color: #bbb;
    text-decoration: none;
    transition: color 0.3s ease;
}

.footer-segment a:hover {
    color: #34A8E0;
}

.footer-bottom {
    text-align: center;
    padding-top: 2rem;
    border-top: 1px solid #34495E;
    color: #999;
}

/* Age Verification Modal */
.age-verification-modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.95);
    z-index: 10000;
    justify-content: center;
    align-items: center;
}

.age-verification-modal.active {
    display: flex;
}

.verification-card {
    background: white;
    padding: 3.5rem;
    border-radius: 25px;
    text-align: center;
    max-width: 550px;
    box-shadow: 0 25px 80px rgba(0, 0, 0, 0.6);
}

.verification-icon {
    font-size: 5rem;
    margin-bottom: 1.5rem;
}

.verification-card h2 {
    color: #2C3E50;
    font-size: 2.5rem;
    font-weight: 800;
    margin-bottom: 1.5rem;
}

.verification-card p {
    font-size: 1.2rem;
    color: #555;
    margin-bottom: 1rem;
}

.verification-buttons {
    display: flex;
    gap: 1.5rem;
    margin-top: 2.5rem;
}

.verify-btn {
    flex: 1;
    padding: 1.3rem 2rem;
    font-size: 1.2rem;
    border: none;
    border-radius: 12px;
    cursor: pointer;
    font-weight: 700;
    transition: all 0.3s ease;
}

.verify-btn.primary {
    background: #2C3E50;
    color: white;
}

.verify-btn.primary:hover {
    background: #1A252F;
    transform: translateY(-3px);
    box-shadow: 0 10px 30px rgba(44, 62, 80, 0.4);
}

.verify-btn.secondary {
    background: #e0e0e0;
    color: #333;
}

.verify-btn.secondary:hover {
    background: #d0d0d0;
}

/* Mobile Styles */
@media (max-width: 768px) {
    .mobile-nav-btn {
        display: flex;
    }

    .site-navigation {
        position: fixed;
        top: 75px;
        right: -100%;
        width: 75%;
        height: calc(100vh - 75px);
        background: white;
        flex-direction: column;
        padding: 2rem;
        box-shadow: -5px 0 20px rgba(0, 0, 0, 0.3);
        transition: right 0.3s ease;
        gap: 0;
    }

    .site-navigation.active {
        right: 0;
    }

    .nav-link {
        color: #2C3E50;
        padding: 1.2rem 0;
        border-bottom: 1px solid #eee;
    }

    .hero-container h1 {
        font-size: 2.5rem;
    }

    .hero-description {
        font-size: 1.2rem;
    }

    .intro-layout {
        grid-template-columns: 1fr;
    }

    .visual-element {
        width: 250px;
        height: 250px;
    }

    .game-container iframe,
    .play-game-container iframe {
        height: 400px;
    }

    .verification-card {
        margin: 1rem;
        padding: 2rem;
    }

    .verification-buttons {
        flex-direction: column;
    }
}