/* KT Telecop Duo - MongCop Renewal Style */
* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: 'Malgun Gothic', 'Apple SD Gothic Neo', sans-serif;
}

body {
    background-color: #ffffff;
    color: #333333;
    overflow-x: hidden;
    line-height: 1.5;
}

/* Common Layout Containers */
.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    position: relative;
}

/* Header Section */
header {
    width: 100%;
    height: 80px;
    background-color: rgba(255, 255, 255, 0.98);
    border-bottom: 1px solid #eeeeee;
    position: fixed;
    top: 0;
    left: 0;
    z-index: 1000;
}

header .container {
    display: block;
    height: 100%;
}

.logo {
    float: left;
    margin-top: 24px;
}

.logo a {
    font-size: 24px;
    font-weight: bold;
    color: #002D5A;
    text-decoration: none;
    letter-spacing: -1px;
}

.logo span {
    color: #EC4899;
}

nav {
    float: right;
    margin-top: 28px;
}

nav ul {
    list-style: none;
}

nav ul li {
    display: inline-block;
    margin-left: 35px;
}

nav ul li a {
    font-size: 16px;
    color: #333333;
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s;
}

nav ul li a:hover {
    color: #2563EB;
}

/* [추가] 모바일용 CSS 애니메이션 햄버거 버튼 스타일 구현 */
.hamburger-btn {
    display: none;
    float: right;
    width: 26px;
    height: 20px;
    margin-top: 30px;
    background: none;
    border: none;
    cursor: pointer;
    position: relative;
    z-index: 1001;
}

.hamburger-btn span {
    display: block;
    position: absolute;
    height: 3px;
    width: 100%;
    background: #111827;
    border-radius: 3px;
    left: 0;
    transition: all 0.3s ease;
}

.hamburger-btn span:nth-child(1) { top: 0px; }
.hamburger-btn span:nth-child(2) { top: 8px; }
.hamburger-btn span:nth-child(3) { top: 16px; }

/* 햄버거 활성화(X 형태 변형) 모션 코드 */
.hamburger-btn.active span:nth-child(1) { top: 8px; transform: rotate(45deg); }
.hamburger-btn.active span:nth-child(2) { opacity: 0; transform: translateX(-20px); }
.hamburger-btn.active span:nth-child(3) { top: 8px; transform: rotate(-45deg); }


/* Main Banner Section */
.main-banner {
    width: 100%;
    margin-top: 80px;
    background: linear-gradient(90deg, #052c63 0%, #0a3d7a 30%, #124a8f 50%, #164c9a 70%, #1a5aad 100%);
    text-align: center;
    overflow: hidden;
    position: relative;
}

.main-banner::before {
    content: "";
    position: absolute;
    inset: 0;
    background: url("../img/bigbanner_1200x620.png") center center / cover no-repeat;
    filter: blur(28px);
    transform: scale(1.08);
    opacity: 0.85;
    z-index: 0;
}

.main-banner .banner-img {
    display: block;
    max-width: 1200px;
    width: 100%;
    height: auto;
    margin: 0 auto;
    position: relative;
    z-index: 1;
}

/* Duo Service Features Section */
.features {
    padding: 100px 0;
    background-color: #F9FAFB;
}

.section-title {
    text-align: center;
    margin-bottom: 60px;
}

.section-title h2 {
    font-size: 32px;
    font-weight: 700;
    color: #111827;
    margin-bottom: 15px;
}

.section-title p {
    font-size: 16px;
    color: #6B7280;
}

.feature-grid {
    display: flex;
    flex-wrap: wrap;
    justify-content: space-between;
    gap: 26px 20px;
}

.feature-card {
    width: calc(25% - 15px);
    background: #ffffff;
    padding: 40px 25px;
    border-radius: 12px;
    border: 1px solid #E5E7EB;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.05);
    transition: transform 0.3s, box-shadow 0.3s;
}

.feature-card:hover {
    transform: translateY(-8px);
    box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
    border-color: #2563EB;
}

.icon-wrapper {
    width: 64px;
    height: 64px;
    border-radius: 16px;
    background: linear-gradient(135deg, #EFF6FF 0%, #DBEAFE 100%);
    margin: 0 auto 25px;
    padding: 12px;
    box-shadow: 0 4px 12px rgba(37, 99, 235, 0.15);
}

.icon-wrapper svg {
    width: 100%;
    height: 100%;
    display: block;
}

.feature-card h3 {
    font-size: 20px;
    font-weight: 700;
    color: #111827;
    margin-bottom: 12px;
    text-align: center;
}

.feature-card p {
    font-size: 14px;
    color: #4B5563;
    line-height: 1.6;
}

/* Footer Section */
footer {
    width: 100%;
    background-color: #111827;
    color: #9CA3AF;
    padding: 60px 0;
    border-top: 1px solid #1F2937;
    font-size: 14px;
}

.footer-top {
    border-bottom: 1px solid #1F2937;
    padding-bottom: 30px;
    margin-bottom: 30px;
    clear: both;
}

.footer-links {
    float: left;
}

.footer-links a {
    color: #D1D5DB;
    text-decoration: none;
    margin-right: 25px;
    font-weight: 500;
}

.footer-links a:hover {
    color: #ffffff;
}

.footer-info {
    clear: both;
    line-height: 1.8;
}

.footer-info p {
    margin-bottom: 6px;
}

.footer-info span {
    margin-right: 20px;
    display: inline-block;
}

.copyright {
    margin-top: 20px;
    color: #6B7280;
    font-size: 13px;
}

/* Clearfix Utility */
.clearfix::after {
    content: "";
    clear: both;
    display: table;
}

/* ==========================================================================
   Responsive Media Queries (미디어 쿼리 구간 관리)
   ========================================================================== */

@media screen and (max-width: 1024px) {
    .feature-card {
        width: calc(50% - 10px);
    }
    .features {
        padding: 60px 0;
    }
}

/* 모바일 구간 브레이크 포인트 (768px 분기) */
@media screen and (max-width: 768px) {
    header {
        height: 80px;
    }
    .main-banner {
        margin-top: 80px;
    }
    
    /* 1. 햄버거 스위치 노출 */
    .hamburger-btn {
        display: block;
    }
    
    /* 2. 모바일 메뉴 전체화면 오버레이 드롭다운 레이아웃 구조 전면 재설정 */
    nav {
        position: fixed;
        top: 80px;
        left: 0;
        width: 100%;
        height: 0; /* 평소에는 숨김 */
        background-color: #ffffff;
        float: none;
        margin-top: 0;
        overflow: hidden;
        transition: height 0.3s ease;
        border-bottom: 0 solid #eee;
        box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.05);
    }
    
    /* 자바스크립트 .active 작동 시 슬라이드 커튼식 노출 */
    nav.active {
        height: 240px; /* 메뉴 높이에 맞춰 조절 */
        border-bottom: 1px solid #eeeeee;
    }
    
    nav ul {
        padding: 15px 20px;
    }
    
    nav ul li {
        display: block;
        margin-left: 0;
        text-align: left;
        border-bottom: 1px solid #f9f9f9;
    }
    
    nav ul li:last-child {
        border-bottom: none;
    }
    
    nav ul li a {
        display: block;
        padding: 12px 10px;
        font-size: 15px;
        color: #111827;
    }
    
    .section-title h2 {
        font-size: 26px;
    }
    
    .feature-card {
        width: 100%;
        padding: 35px 20px;
    }
    
    .footer-links a {
        margin-right: 15px;
        font-size: 13px;
    }
}

@media screen and (max-width: 480px) {
    .footer-links a {
        display: inline-block;
        margin-bottom: 10px;
    }
    .footer-info span {
        display: block;
        margin-right: 0;
        margin-bottom: 5px;
    }
}