/* CSS Variables */
:root {
    --color-primary: #0c2c65; /* Deep Navy - Official */
    --color-secondary: #3ea748; /* Accent Green */
    --color-text-dark: #1a1a1a;
    --color-text-medium: #4a4a4a;
    --color-text-light: #777777;
    --color-bg-page: #ffffff;
    --color-bg-section: #f4f6f9; /* Light Gray for contrast */
    --color-border: #e0e0e0;
    --color-white: #ffffff;
    
    --font-main: 'Noto Sans KR', sans-serif;
    
    --container-width: 1200px;
    --header-height: 80px;
    --border-radius: 4px; /* More squared/academic look */
    --shadow-card: 0 4px 20px rgba(0,0,0,0.06);
    --transition-speed: 0.3s;
}

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

body {
    font-family: var(--font-main);
    color: var(--color-text-dark);
    line-height: 1.7;
    background-color: var(--color-bg-page);
    -webkit-font-smoothing: antialiased;
}

a {
    text-decoration: none;
    color: inherit;
    transition: all var(--transition-speed);
}

ul {
    list-style: none;
}

/* Typography */
h1, h2, h3 {
    font-weight: 700;
    letter-spacing: -0.02em;
}

.section-title {
    font-size: 2rem;
    color: var(--color-primary);
    margin-bottom: 40px;
    position: relative;
    display: flex;
    align-items: center;
    gap: 12px;
}

.section-title::before {
    content: '';
    display: block;
    width: 6px;
    height: 24px;
    background-color: var(--color-primary);
}

.text-paragraph {
    margin-bottom: 1.2rem;
    font-size: 1.05rem;
    word-break: keep-all;
    color: var(--color-text-medium);
}

/* Layout Utilities */
.container {
    width: 90%;
    max-width: var(--container-width);
    margin: 0 auto;
    padding: 0 20px;
}

.section {
    padding: 100px 0;
}

/* Header - Official Deep Navy */
.header {
    background-color: var(--color-primary);
    width: 100%;
    height: var(--header-height);
    position: fixed;
    top: 0;
    z-index: 1000;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    transition: background-color var(--transition-speed);
}

.header-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 100%;
}

.logo {
    display: flex;
    align-items: center;
    color: var(--color-white);
    font-size: 1.4rem;
    font-weight: 700;
    letter-spacing: 0.5px;
}

.nav-list {
    display: flex;
    gap: 40px;
}

.nav-link {
    color: rgba(255, 255, 255, 0.85);
    font-weight: 500;
    font-size: 1rem;
    position: relative;
    padding: 5px 0;
}

.nav-link:hover {
    color: var(--color-white);
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background-color: var(--color-secondary);
    transition: width var(--transition-speed);
}

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

/* Mobile Menu Button */
.mobile-menu-btn {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    flex-direction: column;
    gap: 6px;
}

.bar {
    width: 24px;
    height: 2px;
    background-color: var(--color-white);
    transition: all 0.3s;
}

/* Hero Section */
.hero {
    min-height: 60vh; /* Changed from fixed height to min-height */
    /* min-height: 400px; is handled by the 60vh or we can keep it if we want a hard minimum */
    background-image: linear-gradient(135deg, #09204a 0%, #153a7a 100%);
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    color: var(--color-white);
    padding-top: calc(var(--header-height) + 60px); /* Extra space for header + breathing room */
    padding-bottom: 60px; /* Ensure button doesn't touch the bottom */
    margin-bottom: 0;
}

.hero-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: url('data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciIHdpZHRoPSI0IiBoZWlnaHQ9IjQiPgo8cmVjdCB3aWR0aD0iNCIgaGVpZ2h0PSI0IiBmaWxsPSIjZmZmIiBmaWxsLW9wYWNpdHk9IjAuMDUiLz4KPC9zdmc+'); /* Subtle pattern */
    opacity: 0.3;
}

.hero-content {
    position: relative;
    z-index: 2;
    max-width: 800px;
}

.hero-title {
    font-size: 2.8rem;
    margin-bottom: 20px;
    text-shadow: 0 2px 4px rgba(0,0,0,0.3);
}

.hero-subtitle {
    font-size: 1.2rem;
    font-weight: 300;
    opacity: 0.9;
    margin-bottom: 40px;
}

.btn {
    display: inline-block;
    padding: 14px 40px;
    background-color: transparent;
    border: 1px solid rgba(255,255,255,0.3);
    color: var(--color-white);
    font-weight: 500;
    border-radius: var(--border-radius);
}

.btn:hover {
    background-color: var(--color-white);
    color: var(--color-primary);
    border-color: var(--color-white);
}

/* Greetings Section - Clean White */
.greetings-section {
    background-color: var(--color-white);
    border-bottom: 1px solid var(--color-border);
}

/* Community Section - Card Layout */
.community-section {
    background-color: var(--color-bg-section);
}

.grid-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

.card {
    background: var(--color-white);
    border-radius: var(--border-radius);
    padding: 40px; /* Spacious academic look */
    box-shadow: var(--shadow-card);
    transition: transform var(--transition-speed), box-shadow var(--transition-speed);
    border-top: 4px solid var(--color-primary); /* Brand accent */
    height: 100%;
    display: flex;
    flex-direction: column;
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgba(0,0,0,0.1);
}

.card-header {
    margin-bottom: 25px;
    display: flex;
    align-items: center;
    gap: 15px;
}

.card-icon {
    width: 40px;
    height: 40px;
    background-color: rgba(12, 44, 101, 0.05); /* Light Navy tint */
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
    color: var(--color-primary);
}

.card-title {
    font-size: 1.25rem;
    color: var(--color-primary);
    margin: 0;
}

.card-body {
    flex-grow: 1;
}

.info-box {
    background-color: #f8f9fa;
    padding: 15px;
    border-radius: 4px;
    font-size: 0.95rem;
    color: var(--color-text-medium);
    margin-top: 20px;
    border-left: 3px solid var(--color-primary);
}

.link {
    color: var(--color-primary);
    font-weight: 500;
    border-bottom: 1px solid rgba(12, 44, 101, 0.2);
}

.link:hover {
    border-bottom-color: var(--color-primary);
}

/* Footer */
.footer {
    background-color: var(--color-primary);
    color: rgba(255,255,255,0.7);
    padding: 60px 0;
    font-size: 0.9rem;
    border-top: 1px solid rgba(255,255,255,0.1);
}

.footer-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 10px;
}

.footer-logo {
    color: var(--color-white);
    font-size: 1.2rem;
    font-weight: 700;
    margin-bottom: 10px;
}

/* Responsive */
@media (max-width: 768px) {
    .section {
        padding: 60px 0;
    }
    
    .hero-title {
        font-size: 2rem;
    }
    
    .mobile-menu-btn {
        display: flex;
    }
    
    .nav {
        position: fixed;
        top: var(--header-height);
        left: 0;
        width: 100%;
        background-color: var(--color-primary); /* Navy on mobile too */
        padding: 20px;
        transform: translateY(-150%);
        transition: transform 0.3s ease-in-out;
        box-shadow: 0 10px 20px rgba(0,0,0,0.1);
    }
    
    .nav.active {
        transform: translateY(0);
    }
    
    .nav-list {
        flex-direction: column;
        align-items: center;
    }
    
    .nav-link {
        color: var(--color-white);
        font-size: 1.1rem;
    }
}