/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    background: #1e40af;
}

body {
    font-family: 'Pretendard', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    line-height: 1.6;
    color: #333;
    background: #1e40af;
}

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

/* Header Styles */
.header {
    background: linear-gradient(135deg, #0f172a 0%, #1e293b 50%, #334155 100%);
    padding: 1rem 0;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

.header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo h1 {
    color: white;
    font-size: 1.5rem;
    font-weight: 700;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.3);
}

.logo a {
    text-decoration: none;
    color: inherit;
    transition: color 0.3s ease;
}

.logo a:hover {
    color: #93c5fd;
}

/* Navigation Styles */
.nav-menu {
    display: flex;
    list-style: none;
    align-items: center;
    gap: 2rem;
}

.nav-link {
    color: white;
    text-decoration: none;
    font-weight: 500;
    padding: 0.5rem 1rem;
    border-radius: 6px;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.nav-link:hover {
    background: rgba(255, 255, 255, 0.1);
    transform: translateY(-2px);
}

.register-btn {
    background: linear-gradient(135deg, #10b981 0%, #059669 100%);
    color: white;
    padding: 0.75rem 1.5rem;
    border-radius: 25px;
    font-weight: 600;
    box-shadow: 0 4px 15px rgba(16, 185, 129, 0.3);
    transition: all 0.3s ease;
}

.register-btn:hover {
    transform: translateY(-3px);
    box-shadow: 0 6px 20px rgba(16, 185, 129, 0.4);
    background: linear-gradient(135deg, #059669 0%, #047857 100%);
}

/* Dropdown Styles */
.dropdown {
    position: relative;
}

.dropdown-menu {
    position: absolute;
    top: 100%;
    left: 0;
    background: white;
    border-radius: 8px;
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.15);
    min-width: 200px;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: all 0.3s ease;
    list-style: none;
    padding: 0.5rem 0;
}

.dropdown:hover .dropdown-menu,
.dropdown-menu.show {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.dropdown-menu li a {
    display: block;
    padding: 0.75rem 1.5rem;
    color: #333;
    text-decoration: none;
    transition: background 0.3s ease;
}

.dropdown-menu li a:hover {
    background: #f1f5f9;
    color: #1e3a8a;
}

/* Mobile Menu Toggle */
.mobile-menu-toggle {
    display: none;
    color: white;
    font-size: 1.5rem;
    cursor: pointer;
    z-index: 1000;
}

/* Hero Section */
.hero {
    background: linear-gradient(135deg, #1e40af 0%, #3b82f6 30%, #60a5fa 70%, #93c5fd 100%);
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding-top: 80px;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><defs><pattern id="grid" width="15" height="15" patternUnits="userSpaceOnUse"><path d="M 15 0 L 0 0 0 15" fill="none" stroke="rgba(255,255,255,0.2)" stroke-width="0.8"/></pattern></defs><rect width="100" height="100" fill="url(%23grid)"/></svg>');
    opacity: 0.5;
}

.hero-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: flex-start;
    position: relative;
    z-index: 2;
    padding-top: 2rem;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 700;
    color: white;
    margin-bottom: 1rem;
    line-height: 1.2;
    text-shadow: 0 4px 8px rgba(0, 0, 0, 0.3);
}

.hero-subtitle {
    font-size: 1.5rem;
    color: #fbbf24;
    margin-bottom: 2rem;
    font-weight: 600;
}

.hero-info {
    color: white;
    font-size: 1.1rem;
    margin-top: 3rem;
}

.hero-info p {
    margin-bottom: 0.5rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.hero-info i {
    color: #fbbf24;
    width: 20px;
}

/* AI Logo */
.hero-visual {
    display: flex;
    justify-content: center;
    align-items: center;
}

.ai-logo {
    width: 200px;
    height: 200px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    backdrop-filter: blur(10px);
    border: 2px solid rgba(255, 255, 255, 0.2);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.2);
}

.ai-text {
    font-size: 4rem;
    font-weight: 700;
    color: white;
    text-shadow: 0 4px 8px rgba(0, 0, 0, 0.3);
}

/* Event Overview Section */
.event-overview {
    background: linear-gradient(135deg, #0f172a 0%, #1e293b 50%, #334155 100%);
    padding: 0;
    position: relative;
    overflow: hidden;
}

.event-overview::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: 
        radial-gradient(circle at 20% 80%, rgba(59, 130, 246, 0.1) 0%, transparent 50%),
        radial-gradient(circle at 80% 20%, rgba(16, 185, 129, 0.1) 0%, transparent 50%),
        radial-gradient(circle at 40% 40%, rgba(139, 92, 246, 0.1) 0%, transparent 50%);
    pointer-events: none;
}

.overview-content {
    position: relative;
    z-index: 2;
    text-align: center;
    max-width: 1000px;
    margin: 0 auto;
}

.overview-title {
    font-size: 3rem;
    font-weight: 700;
    color: white;
    margin-bottom: 1rem;
    text-shadow: 0 4px 8px rgba(0, 0, 0, 0.5);
    line-height: 1.2;
}

.overview-subtitle {
    font-size: 1.5rem;
    color: #fbbf24;
    margin-bottom: 3rem;
    font-weight: 600;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.3);
}

.overview-details {
    display: grid;
    gap: 1.5rem;
    max-width: 800px;
    margin: 0 auto;
}

.detail-item {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 1rem 1.5rem;
    background: rgba(255, 255, 255, 0.05);
    border-radius: 12px;
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.1);
    transition: all 0.3s ease;
}

.detail-item:hover {
    background: rgba(255, 255, 255, 0.1);
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.2);
}

.detail-item i {
    color: #fbbf24;
    font-size: 1.2rem;
    width: 24px;
    text-align: center;
}

.detail-item span {
    color: white;
    font-size: 1.1rem;
    font-weight: 500;
}

.detail-item.companies {
    flex-direction: column;
    align-items: flex-start;
    gap: 1rem;
    padding: 1.5rem;
}

.companies-list {
    width: 100%;
}

.companies-list > span {
    display: block;
    margin-bottom: 0.5rem;
    color: #fbbf24;
    font-weight: 600;
}

.company-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.company-tag {
    background: linear-gradient(135deg, #3b82f6 0%, #1e40af 100%);
    color: white;
    padding: 0.5rem 1rem;
    border-radius: 20px;
    font-size: 0.9rem;
    font-weight: 500;
    transition: all 0.3s ease;
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.company-tag:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(59, 130, 246, 0.4);
    background: linear-gradient(135deg, #1e40af 0%, #1e3a8a 100%);
}

/* Main Content Sections */
.main-content {
    padding: 0;
}

.section {
    padding: 0;
    border-bottom: none;
}

.section:last-child {
    border-bottom: none;
}

.section-title {
    font-size: 2.5rem;
    font-weight: 700;
    color: #1e3a8a;
    margin-bottom: 2rem;
    text-align: center;
    position: relative;
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: -10px;
    left: 50%;
    transform: translateX(-50%);
    width: 60px;
    height: 4px;
    background: linear-gradient(135deg, #3b82f6 0%, #1e40af 100%);
    border-radius: 2px;
}

.content-placeholder {
    background: white;
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
    text-align: center;
    color: #6b7280;
    font-size: 1.1rem;
}

.section-links {
    display: flex;
    justify-content: center;
    gap: 1.5rem;
    margin-top: 2rem;
    flex-wrap: wrap;
}

.section-link {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 1rem 1.5rem;
    background: linear-gradient(135deg, #3b82f6 0%, #1e40af 100%);
    color: white;
    text-decoration: none;
    border-radius: 8px;
    font-weight: 600;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px rgba(59, 130, 246, 0.3);
}

.section-link:hover {
    transform: translateY(-3px);
    box-shadow: 0 6px 20px rgba(59, 130, 246, 0.4);
    background: linear-gradient(135deg, #1e40af 0%, #1e3a8a 100%);
}

.section-link i {
    font-size: 1.1rem;
}

/* Footer */
.footer {
    background: linear-gradient(135deg, #0f172a 0%, #1e293b 50%, #334155 100%);
    color: white;
    padding: 3rem 0;
    margin-top: 0;
}

.footer-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
    align-items: center;
}

.footer-logo h3 {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
}

.footer-info p {
    margin-bottom: 0.5rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.footer-info i {
    color: #60a5fa;
    width: 20px;
}

/* Responsive Design */
@media (max-width: 1024px) {
    .nav-menu {
        display: none;
    }
    
    .mobile-menu-toggle {
        display: block;
    }
    
    .logo h1 {
        font-size: 1.2rem;
    }
    
    .hero-content {
        grid-template-columns: 1fr;
        text-align: center;
        gap: 2rem;
    }
    
    .hero-title {
        font-size: 2.5rem;
    }
    
    .hero-subtitle {
        font-size: 1.2rem;
    }
    
    .ai-logo {
        width: 150px;
        height: 150px;
    }
    
    .ai-text {
        font-size: 3rem;
    }
    
    .hero-visual {
        display: none;
    }
    
    .footer-content {
        grid-template-columns: 1fr;
        text-align: center;
    }
    
    .footer-logo {
        display: none;
    }
    
    .nav-menu {
        position: fixed;
        top: 80px;
        left: 0;
        right: 0;
        background: #1e3a8a;
        flex-direction: column;
        padding: 2rem;
        transform: translateY(-100%);
        transition: transform 0.3s ease;
        display: none;
    }
    
    .nav-menu.active {
        transform: translateY(0);
        display: block;
    }
    
    /* Mobile dropdown styles */
    .dropdown {
        position: static;
    }
    
    .dropdown-menu {
        position: static;
        background: transparent;
        box-shadow: none;
        opacity: 1;
        visibility: visible;
        transform: none;
        display: none;
        padding: 0;
        margin-top: 0.5rem;
        margin-left: 1rem;
    }
    
    .dropdown-menu.show {
        display: block;
    }
    
    .dropdown-menu li a {
        color: white;
        padding: 0.5rem 1rem;
    }
    
    .dropdown-menu li a:hover {
        background: rgba(255, 255, 255, 0.1);
        color: white;
    }
    
    /* Event Overview Responsive */
    .overview-title {
        font-size: 2rem;
    }
    
    .overview-subtitle {
        font-size: 1.2rem;
    }
    
    .detail-item {
        flex-direction: column;
        text-align: center;
        gap: 0.5rem;
    }
    
    .detail-item.companies {
        align-items: center;
    }
    
    .company-tags {
        justify-content: center;
    }
    
    .company-tag {
        font-size: 0.8rem;
        padding: 0.4rem 0.8rem;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 15px;
    }
    
    .logo h1 {
        font-size: 1rem;
    }
    
    .hero-title {
        font-size: 2rem;
    }
    
    .section-title {
        font-size: 2rem;
    }
}