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

body {
    font-family: 'Noto Sans KR', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    line-height: 1.6;
    color: #333;
    background: #f5f5f5;
}

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

/* Header */
.site-header {
    background: #fff;
    position: sticky;
    top: 0;
    z-index: 1000;
    border-bottom: 1px solid rgba(15, 23, 42, 0.08);
    box-shadow: 0 10px 40px rgba(15, 23, 42, 0.06);
}

.header-bar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.25rem 20px;
    gap: 1.5rem;
}

.brand a {
    color: #2c3e50;
    text-decoration: none;
    font-size: 1.5rem;
    font-weight: 700;
}

.tagline {
    color: #64748b;
    font-size: 1rem;
}

.mega-nav {
    background: #f8fafc;
    border-top: 1px solid #e2e8f0;
}

.mega-nav .main-menu {
    display: flex;
    list-style: none;
    gap: 1.5rem;
    margin: 0;
    padding: 0;
    align-items: stretch;
}

.menu-item {
    position: relative;
}

.menu-item.has-children .menu-label {
    font-weight: 600;
    color: #0f172a;
    cursor: pointer;
    display: block;
    padding: 1rem 0;
}

.menu-item .sub-menu {
    position: absolute;
    left: 0;
    top: 100%;
    background: #fff;
    padding: 1.5rem;
    border-radius: 14px;
    box-shadow: 0 25px 60px rgba(15, 23, 42, 0.15);
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
    min-width: 520px;
    opacity: 0;
    visibility: hidden;
    transform: translateY(12px);
    transition: opacity 0.2s ease, transform 0.2s ease;
}

.menu-item.has-children:hover .sub-menu {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.menu-item .sub-menu a {
    text-decoration: none;
    background: #f8fafc;
    border-radius: 10px;
    padding: 0.85rem 1rem;
    display: flex;
    flex-direction: column;
    gap: 0.35rem;
    color: #0f172a;
    transition: background 0.2s ease, color 0.2s ease;
}

.menu-item .sub-menu a strong {
    font-size: 1rem;
}

.menu-item .sub-menu a span {
    font-size: 0.85rem;
    color: #64748b;
}

.menu-item .sub-menu a:hover {
    background: #e0f2fe;
    color: #0c4a6e;
}

.menu-item.quick-link a {
    display: inline-block;
    padding: 1rem 0;
    color: #0f172a;
    text-decoration: none;
    font-weight: 600;
    transition: color 0.3s;
}

.menu-item.quick-link a:hover {
    color: #2563eb;
}

/* Hero Section */
.hero {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 4rem 0;
    text-align: center;
}

.hero h2 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.hero p {
    font-size: 1.2rem;
    opacity: 0.9;
}

/* Features */
.features {
    padding: 4rem 0;
}

.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}

.feature-item {
    background: white;
    padding: 2rem;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    text-align: center;
}

.feature-item h3 {
    color: #2c3e50;
    margin-bottom: 1rem;
    font-size: 1.5rem;
}

.feature-item p {
    color: #666;
    margin-bottom: 1.5rem;
}

.highlight-list {
    margin-top: 1.5rem;
    padding-left: 1.25rem;
    color: #374151;
}

.btn {
    display: inline-block;
    padding: 0.75rem 2rem;
    background: #3498db;
    color: white;
    text-decoration: none;
    border-radius: 5px;
    transition: background 0.3s;
}

.btn:hover {
    background: #2980b9;
}

.btn.outline {
    background: transparent;
    border: 1px solid currentColor;
    color: inherit;
}

/* Footer */
footer {
    background: #2c3e50;
    color: white;
    text-align: center;
    padding: 2rem 0;
    margin-top: 4rem;
}

.footer-meta {
    margin-top: 0.5rem;
    color: rgba(255,255,255,0.7);
}

/* Section page */
.section-page .section-hero {
    background: #0f172a;
    color: #fff;
    padding: 3rem 0;
}

.section-group {
    text-transform: uppercase;
    letter-spacing: 0.15em;
    font-size: 0.85rem;
    color: #94a3b8;
}

.section-page h2 {
    font-size: 2.25rem;
    margin: 0.75rem 0;
}

.section-description {
    max-width: 640px;
    color: #cbd5f5;
}

.section-body .container {
    display: grid;
    grid-template-columns: minmax(0, 2fr) minmax(280px, 1fr);
    gap: 2rem;
    padding: 3rem 0;
}

.content-card {
    background: #fff;
    padding: 2rem;
    border-radius: 18px;
    box-shadow: 0 24px 60px rgba(15, 23, 42, 0.1);
}

.content-card h3 {
    margin-bottom: 1rem;
    color: #0f172a;
}

.section-side .info-panel {
    background: #111827;
    color: #f8fafc;
    border-radius: 18px;
    padding: 2rem;
}

.section-side ul {
    list-style: none;
    margin: 1rem 0 0 0;
    padding: 0;
}

.section-side li {
    margin-bottom: 0.35rem;
}

.section-side .btn {
    margin-top: 1.5rem;
    border-color: rgba(255,255,255,0.6);
    color: #fff;
    background: transparent;
}

.section-side .btn:hover {
    background: rgba(255,255,255,0.1);
}

/* Mobile Menu Toggle */
.mobile-menu-toggle {
    display: none;
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: #2c3e50;
    padding: 0.5rem;
}

.mobile-menu-toggle:focus {
    outline: 2px solid #3498db;
    outline-offset: 2px;
}

/* Responsive */
@media (max-width: 768px) {
    .container {
        padding: 0 16px;
    }
    
    .header-bar {
        flex-direction: row;
        align-items: center;
        justify-content: space-between;
        padding: 1rem 16px;
    }
    
    .brand a {
        font-size: 1.25rem;
    }
    
    .tagline {
        display: none;
    }
    
    .mobile-menu-toggle {
        display: block;
    }
    
    .mega-nav {
        display: none;
        border-top: 1px solid #e2e8f0;
    }
    
    .mega-nav.active {
        display: block;
    }
    
    .mega-nav .main-menu {
        flex-direction: column;
        gap: 0;
    }
    
    .menu-item {
        border-bottom: 1px solid #e2e8f0;
    }
    
    .menu-item.has-children .menu-label {
        padding: 1rem 16px;
        display: flex;
        justify-content: space-between;
        align-items: center;
    }
    
    .menu-item.has-children .menu-label::after {
        content: '▼';
        font-size: 0.75rem;
        transition: transform 0.3s;
    }
    
    .menu-item.has-children.active .menu-label::after {
        transform: rotate(180deg);
    }
    
    .menu-item .sub-menu {
        position: static;
        transform: none;
        opacity: 1;
        visibility: visible;
        box-shadow: none;
        padding: 0;
        min-width: unset;
        background: #f8fafc;
        grid-template-columns: 1fr;
        display: none;
        border-top: 1px solid #e2e8f0;
    }
    
    .menu-item.has-children.active .sub-menu {
        display: grid;
    }
    
    .menu-item .sub-menu a {
        padding: 1rem 16px;
        border-radius: 0;
        background: transparent;
        border-bottom: 1px solid #e2e8f0;
    }
    
    .menu-item.quick-link a {
        padding: 1rem 16px;
        display: block;
    }
    
    .hero {
        padding: 2.5rem 0;
    }
    
    .hero h2 {
        font-size: 1.75rem;
    }
    
    .hero p {
        font-size: 1rem;
    }
    
    .features {
        padding: 2.5rem 0;
    }
    
    .feature-grid {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }
    
    .feature-item {
        padding: 1.5rem;
    }
    
    .feature-item h3 {
        font-size: 1.25rem;
    }
    
    .btn {
        padding: 0.875rem 1.5rem;
        font-size: 1rem;
        min-height: 44px; /* 터치 친화적 */
    }
    
    .section-page .section-hero {
        padding: 2rem 0;
    }
    
    .section-page h2 {
        font-size: 1.75rem;
    }
    
    .section-body .container {
        grid-template-columns: 1fr;
        gap: 1.5rem;
        padding: 2rem 0;
    }
    
    .content-card,
    .section-side .info-panel {
        padding: 1.5rem;
    }
}

@media (max-width: 480px) {
    .hero h2 {
        font-size: 1.5rem;
    }
    
    .section-page h2 {
        font-size: 1.5rem;
    }
}