/* 전체 페이지 기본 */
html, body {
    margin: 0;
    padding: 0;
    height: 100%;
    font-family: 'Arial', sans-serif;
    background: linear-gradient(135deg, #fce3ec, #e0f7fa, #f3e5f5);
    background-size: 400% 400%;
    animation: gradientBG 12s ease infinite;
    color: #444;
}

body {
    display: flex;
    flex-direction: column;
    padding-top: 70px; /* 네비게이션 바 높이만큼 여백 */
}

/* 네비게이션 바 */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid rgba(0, 0, 0, 0.1);
    z-index: 1000;
    padding: 0;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 20px;
    height: 70px;
}

.nav-logo a {
    display: flex;
    align-items: center;
    text-decoration: none;
    color: #333;
    font-weight: bold;
    font-size: 18px;
}

.logo-icon {
    font-size: 24px;
    margin-right: 8px;
}

.logo-text {
    font-family: 'Trebuchet MS', sans-serif;
}

.nav-menu {
    display: flex;
    align-items: center;
    gap: 20px;
}

.nav-link {
    text-decoration: none;
    color: #333;
    font-weight: 500;
    padding: 8px 16px;
    border-radius: 20px;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    gap: 5px;
}

.nav-link:hover {
    background: rgba(76, 175, 80, 0.1);
    color: #4caf50;
    transform: translateY(-1px);
}

.login-btn {
    background: #4caf50;
    color: white !important;
}

.login-btn:hover {
    background: #45a049;
    color: white !important;
}

/* 사용자 드롭다운 */
.nav-user {
    position: relative;
}

.user-dropdown {
    position: relative;
}

.user-btn {
    background: none;
    border: none;
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 8px 16px;
    border-radius: 20px;
    cursor: pointer;
    transition: all 0.3s ease;
    color: #333;
    font-weight: 500;
}

.user-btn:hover {
    background: rgba(76, 175, 80, 0.1);
    color: #4caf50;
}

.user-avatar {
    width: 24px;
    height: 24px;
    border-radius: 50%;
    object-fit: cover;
}

.dropdown-arrow {
    font-size: 12px;
    transition: transform 0.3s ease;
}

.user-dropdown.active .dropdown-arrow {
    transform: rotate(180deg);
}

.dropdown-menu {
    position: absolute;
    top: 100%;
    right: 0;
    background: white;
    border-radius: 12px;
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.15);
    padding: 8px 0;
    min-width: 180px;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: all 0.3s ease;
    z-index: 1001;
}

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

.dropdown-item {
    display: block;
    padding: 12px 20px;
    text-decoration: none;
    color: #333;
    transition: background 0.3s ease;
    border: none;
    background: none;
    width: 100%;
    text-align: left;
    cursor: pointer;
    font-size: 14px;
}

.dropdown-item:hover {
    background: rgba(76, 175, 80, 0.1);
    color: #4caf50;
}

.dropdown-divider {
    border: none;
    border-top: 1px solid #eee;
    margin: 8px 0;
}

.logout-btn {
    color: #e74c3c !important;
}

.logout-btn:hover {
    background: rgba(231, 76, 60, 0.1) !important;
    color: #e74c3c !important;
}

/* 모바일 메뉴 토글 */
.nav-toggle {
    display: none;
    flex-direction: column;
    cursor: pointer;
    gap: 4px;
}

.bar {
    width: 25px;
    height: 3px;
    background: #333;
    border-radius: 2px;
    transition: all 0.3s ease;
}

/* 메인 컨텐츠 */
.main-content {
    flex: 1; /* 남은 공간을 모두 차지 */
    padding: 20px 0;
    display: flex;
    flex-direction: column;
}

/* 푸터 */
.footer {
    background: rgba(255, 255, 255, 0.9);
    border-top: 1px solid rgba(0, 0, 0, 0.1);
    margin-top: auto; /* 자동으로 아래쪽에 배치 */
    flex-shrink: 0; /* footer 크기 고정 */
}

.footer-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 30px 20px 20px;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
    margin-bottom: 20px;
}

.footer-section h4 {
    color: #333;
    margin-bottom: 15px;
    font-size: 16px;
}

.footer-section p {
    color: #666;
    line-height: 1.6;
    margin: 0;
}

.footer-section ul {
    list-style: none;
    padding: 0;
    margin: 0;
}

.footer-section ul li {
    margin-bottom: 8px;
}

.footer-section ul li a {
    color: #666;
    text-decoration: none;
    transition: color 0.3s ease;
}

.footer-section ul li a:hover {
    color: #4caf50;
}

.footer-bottom {
    text-align: center;
    padding-top: 20px;
    border-top: 1px solid #eee;
    color: #999;
    font-size: 14px;
}

/* 모바일 반응형 */
@media (max-width: 768px) {
    .nav-toggle {
        display: flex;
    }
    
    .nav-menu {
        position: fixed;
        top: 70px;
        left: -100%;
        width: 100%;
        height: calc(100vh - 70px);
        background: rgba(255, 255, 255, 0.98);
        backdrop-filter: blur(10px);
        flex-direction: column;
        justify-content: flex-start;
        align-items: center;
        padding-top: 30px;
        padding-bottom: 30px;
        transition: left 0.3s ease;
        gap: 15px;
        overflow-y: auto;
        -webkit-overflow-scrolling: touch;
    }
    
    .nav-menu.active {
        left: 0;
    }
    
    .nav-link {
        font-size: 16px;
        padding: 12px 25px;
    }
    
    .dropdown-menu {
        position: static;
        opacity: 1;
        visibility: visible;
        transform: none;
        box-shadow: none;
        background: rgba(0, 0, 0, 0.05);
        margin-top: 10px;
        border-radius: 8px;
    }
    
    .dropdown-menu.active {
        display: block;
    }
    
    .footer-content {
        grid-template-columns: 1fr;
        text-align: center;
    }
}

/* 부드러운 배경 애니메이션 */
@keyframes gradientBG {
    0% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
    100% { background-position: 0% 50%; }
}

/* 제목 */
h1, h2, h3 {
    font-family: 'Trebuchet MS', sans-serif;
    text-align: center;
    color: #333;
}

/* 챌린지 카드 그리드 */
.challenge-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 20px;
    padding: 20px;
}

/* Instagram 갤러리 그리드 */
.instagram-gallery {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 15px;
    padding: 20px;
    max-width: 1200px;
    margin: 0 auto;
}

/* Instagram 카드 */
.instagram-card {
    position: relative;
    background: white;
    border-radius: 12px;
    overflow: hidden;
    box-shadow: 0 4px 12px rgba(0,0,0,0.08);
    transition: transform 0.25s ease, box-shadow 0.25s ease;
    aspect-ratio: 1; /* 정사각형 유지 */
}

/* 이미지 실패 시 카드 전체 숨김 처리됨 */

.instagram-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 20px rgba(0,0,0,0.15);
}

.instagram-card img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.3s ease;
    display: block;
}

.instagram-card:hover img {
    transform: scale(1.05);
}

/* Instagram 오버레이 */
.instagram-overlay {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(45deg, rgba(0,0,0,0.8), rgba(0,0,0,0.4));
    opacity: 0;
    transition: opacity 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 15px;
}

.instagram-card:hover .instagram-overlay {
    opacity: 1;
}

.instagram-content {
    text-align: center;
    width: 100%;
}

.instagram-hashtag {
    color: #FFD700;
    font-size: 16px;
    font-weight: bold;
    margin: 0 0 8px 0;
    text-shadow: 1px 1px 2px rgba(0,0,0,0.8);
}

.instagram-caption {
    color: white;
    font-size: 12px;
    margin: 0 0 15px 0;
    line-height: 1.3;
    opacity: 0.9;
}

.instagram-link {
    color: white;
    text-decoration: none;
    background: rgba(255,255,255,0.2);
    padding: 8px 16px;
    border-radius: 20px;
    font-size: 14px;
    font-weight: bold;
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255,255,255,0.3);
    transition: all 0.2s ease;
    display: inline-block;
}

.instagram-link:hover {
    background: rgba(255,255,255,0.3);
    transform: scale(1.05);
}

/* 카드 디자인 */
.challenge-card, .submission-card {
    background: white;
    border-radius: 16px;
    box-shadow: 0 4px 12px rgba(0,0,0,0.08);
    padding: 20px;
    text-align: center;
    transition: transform 0.25s ease, box-shadow 0.25s ease;
}
.challenge-card:hover, .submission-card:hover {
    transform: translateY(-6px);
    box-shadow: 0 8px 18px rgba(0,0,0,0.12);
}

/* 버튼 */
.detail-btn, button {
    display: inline-block;
    margin-top: 10px;
    padding: 10px 18px;
    border: none;
    border-radius: 30px;
    font-size: 14px;
    cursor: pointer;
    background: linear-gradient(45deg, #ffb6c1, #ffe0b2, #c8e6c9);
    background-size: 200% 200%;
    color: #333;
    text-decoration: none;
    transition: all 0.3s ease;
}
.detail-btn:hover, button:hover {
    background-position: right center;
    color: #000;
}

/* 우승자 하이라이트 */
.winner {
    border: 3px solid gold !important;
    box-shadow: 0 0 12px rgba(255,215,0,0.6);
}

/* 푸터 */
footer {
    background: rgba(255, 255, 255, 0.6);
    padding: 15px;
    text-align: center;
    font-size: 13px;
    border-top: 1px solid rgba(0,0,0,0.1);
}

/* 모바일 반응형 - 갤러리 그리드 */
@media (max-width: 768px) {
    .instagram-gallery {
        grid-template-columns: repeat(3, 1fr);
        gap: 8px;
        padding: 10px;
    }
    
    .instagram-card {
        border-radius: 8px;
    }
}

@media (max-width: 480px) {
    .instagram-gallery {
        grid-template-columns: repeat(3, 1fr);
        gap: 6px;
        padding: 8px;
    }
    
    .instagram-card {
        border-radius: 6px;
    }
    
    .nav-menu {
        padding-top: 20px;
        padding-bottom: 20px;
        gap: 10px;
    }
    
    .nav-link {
        font-size: 15px;
        padding: 10px 20px;
    }
}

/* Mat Scanner Button */
.scanner-btn {
    background: linear-gradient(135deg, #4caf50, #45a049);
    color: white;
    border: none;
    padding: 15px 30px;
    border-radius: 25px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 10px;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px rgba(76, 175, 80, 0.3);
    margin: 20px auto;
    max-width: 300px;
}

.scanner-btn:hover {
    background: linear-gradient(135deg, #45a049, #3d8b40);
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(76, 175, 80, 0.4);
}

.scanner-btn:active {
    transform: translateY(0);
    box-shadow: 0 2px 10px rgba(76, 175, 80, 0.3);
}

.btn-icon {
    font-size: 18px;
}

.btn-text {
    flex: 1;
    text-align: center;
}

.scanner-hint {
    text-align: center;
    color: #666;
    font-size: 14px;
    margin-top: 10px;
    font-style: italic;
}

/* Utilities: force-hide helper */
.hidden,
[hidden] {
    display: none !important;
}