:root {
    --primary-color: #003366; /* 딥 블루 */
    --secondary-color: #f4f4f4;
    --text-color: #333;
    --white: #ffffff;
}

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

body {
    font-family: 'Pretendard', sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    overflow-x: hidden;
}

.container {
    width: 90%;
    max-width: 1200px;
    margin: 0 auto;
}

/* Header */
header {
    background: var(--white);
    padding: 20px 0;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    position: sticky;
    top: 0;
    z-index: 1000;
}

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

header h1 a {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: bold;
}

nav ul {
    display: flex;
    list-style: none;
}

nav ul li {
    margin-left: 20px;
}

nav ul li a {
    text-decoration: none;
    color: var(--text-color);
    font-weight: 500;
}

/* Hero Slider */
.hero {
    height: 80vh;
    position: relative;
    overflow: hidden;
}

.slide {
    position: absolute;
    width: 100%;
    height: 100%;
    background-size: cover;
    background-position: center;
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    transition: opacity 1s ease-in-out;
    text-align: center;
    color: var(--white);
}

.slide.active {
    opacity: 1;
}

.hero-content h2 {
    font-size: 3rem;
    margin-bottom: 1rem;
}

/* Sections */
.section {
    padding: 80px 0;
}

.bg-light {
    background-color: var(--secondary-color);
}

.section-title {
    text-align: center;
    margin-bottom: 50px;
}

.section-title h2 {
    color: var(--primary-color);
    font-size: 2.5rem;
}

/* Grids & Cards */
.grid-content, .grid-three {
    display: flex;
    gap: 20px;
    flex-wrap: wrap;
}

.card, .service-card {
    flex: 1;
    min-width: 300px;
    background: var(--white);
    padding: 30px;
    border: 1px solid #ddd;
    display: flex;
    flex-direction: column;
    justify-content: center; /* 높이 균일화 핵심 */
}

.service-card img {
    width: 100%;
    height: 250px;
    object-fit: cover;
    margin-bottom: 20px;
}

.highlight-box {
    background: var(--primary-color);
    color: var(--white);
    padding: 60px;
    text-align: center;
    border-radius: 8px;
}

/* Top Button */
#topBtn {
    position: fixed;
    bottom: 30px;
    right: 30px;
    z-index: 99;
    background-color: var(--primary-color);
    color: white;
    border: none;
    padding: 15px;
    border-radius: 50%;
    cursor: pointer;
    display: none;
}

/* Footer */
footer {
    background: #222;
    color: #eee;
    padding: 40px 0 20px;
}

.footer-info {
    text-align: center;
    margin-bottom: 20px;
    font-size: 0.9rem;
}

.copyright {
    text-align: center;
    border-top: 1px solid #444;
    padding-top: 20px;
    font-size: 0.8rem;
}

/* Mobile Responsive */
@media (max-width: 768px) {
    header .container { flex-direction: column; }
    nav ul { margin-top: 15px; }
    .hero-content h2 { font-size: 2rem; }
}