@import url('https://fonts.googleapis.com/css2?family=Noto+Sans+KR:wght@400;700&display=swap');

:root {
    --primary-color: #00529B;
    --secondary-color: #6c757d;
    --accent-color: #FFC107;
    --text-color: #212529;
    --text-color-light: #495057;
    --bg-color: #fff;
    --border-color: #dee2e6;
    --surface-color: #f8f9fa;
    --green: #28a745;
    --red: #dc3545;
}

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

.skip-link {
    position: absolute;
    top: -100px;
    left: 0;
    background: #00529B;
    color: #fff;
    padding: 1rem;
    z-index: 1000;
}

.skip-link:focus {
    top: 0;
}

body {
    font-family: 'Noto Sans KR', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.7;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

.container {
    max-width: 1140px;
    margin: 0 auto;
    padding: 0 1.5rem;
}

h1,
h2,
h3 {
    font-weight: 700;
    line-height: 1.3;
    color: var(--primary-color);
}

h1 {
    font-size: 2.8rem;
}

h2 {
    font-size: 2rem;
}

h3 {
    font-size: 1.25rem;
}

p {
    margin-bottom: 1rem;
    color: var(--text-color-light);
}

a {
    color: var(--primary-color);
    text-decoration: none;
    transition: color 0.2s ease-in-out;
}

a:hover {
    color: #003d73;
}

/* Header */
.site-header {
    border-bottom: 1px solid var(--border-color);
    padding: 1rem 0;
    background-color: var(--bg-color);
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
}

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

.logo {
    font-weight: 700;
    font-size: 1.75rem;
    text-decoration: none;
    color: var(--primary-color);
}

.main-nav {
    display: flex;
    gap: 2rem;
}

.main-nav a {
    text-decoration: none;
    color: var(--text-color);
    font-weight: 500;
    padding-bottom: 5px;
    border-bottom: 2px solid transparent;
    transition: border-color 0.2s ease-in-out;
}

.main-nav a:hover {
    color: var(--primary-color);
    border-bottom-color: var(--primary-color);
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    border-radius: 8px;
    text-decoration: none;
    border: 1px solid transparent;
    font-weight: 700;
    font-size: 1rem;
    transition: all 0.2s ease-in-out;
}

.btn-primary {
    background-color: var(--primary-color);
    color: #fff;
}

.btn-primary:hover {
    background-color: #003d73;
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0, 82, 155, 0.2);
}

.btn-secondary {
    background-color: transparent;
    color: var(--primary-color);
    border-color: var(--primary-color);
}

.btn-secondary:hover {
    background-color: var(--primary-color);
    color: #fff;
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0, 82, 155, 0.15);
}

/* Hero Section */
.hero {
    text-align: center;
    padding: 6rem 1rem;
    background-color: var(--surface-color);
    border-bottom: 1px solid var(--border-color);
}

.hero h1 {
    margin-bottom: 1.5rem;
}

.hero p {
    font-size: 1.2rem;
    max-width: 650px;
    margin: 0 auto 2.5rem auto;
}

.hero-actions {
    display: flex;
    justify-content: center;
    gap: 1rem;
}

/* Feature Section */
.feature-section,
.about-section {
    padding: 5rem 0;
}

.section-title {
    text-align: center;
    margin-bottom: 3rem;
}

.section-title h2 {
    margin-bottom: 0.5rem;
}

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

.tile {
    border: 1px solid var(--border-color);
    padding: 2rem;
    border-radius: 12px;
    text-align: center;
    background-color: #fff;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.05);
    transition: transform 0.2s ease-in-out, box-shadow 0.2s ease-in-out;
}

.tile:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 16px rgba(0, 0, 0, 0.1);
}

.tile-icon {
    font-size: 3rem;
    margin-bottom: 1.5rem;
    line-height: 1;
}

.tile h3 {
    margin-bottom: 0.5rem;
}

/* About Section */
.alternate-bg {
    background-color: var(--surface-color);
    border-top: 1px solid var(--border-color);
    border-bottom: 1px solid var(--border-color);
}

.about-content {
    max-width: 720px;
    margin: 0 auto;
    text-align: center;
    font-size: 1.1rem;
}

/* Footer */
.site-footer {
    margin-top: 0;
    padding: 3rem 0;
    background-color: #1d2d3c;
    color: #a9b4c2;
    text-align: center;
}

.site-footer a {
    color: #fff;
    margin: 0 0.75rem;
}

.site-footer a:hover {
    text-decoration: underline;
}

.footer-links {
    margin-bottom: 1rem;
}

/* Responsive */
@media (max-width: 768px) {
    h1 {
        font-size: 2.2rem;
    }

    h2 {
        font-size: 1.8rem;
    }

    .site-header .container {
        flex-direction: column;
        gap: 1rem;
    }

    .hero {
        padding: 4rem 1rem;
    }
}