/* .NET Universe 컨퍼런스 테마 */
:root {
    --purple-primary: #512BD4;
    --purple-dark: #3B1F9E;
    --purple-light: #7B5CD6;
    --gradient-start: #512BD4;
    --gradient-end: #0D6EFD;
}

html {
    font-size: 14px;
    scroll-behavior: smooth;
}

@media (min-width: 768px) {
    html {
        font-size: 16px;
    }
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

main {
    min-height: calc(100vh - 200px);
}

/* 네비게이션 */
.bg-purple {
    background: linear-gradient(135deg, var(--purple-primary) 0%, var(--purple-dark) 100%);
}

.navbar-brand {
    font-size: 1.5rem;
}

.nav-link {
    font-weight: 500;
    padding: 0.5rem 1rem !important;
    transition: opacity 0.2s;
}

.nav-link:hover {
    opacity: 0.8;
}

/* 히어로 섹션 */
.hero-section {
    background: linear-gradient(135deg, var(--purple-primary) 0%, #1a1a2e 100%);
    position: relative;
    overflow: hidden;
}

/* 페이지 헤더 섹션 (아카이브 등) - sticky navbar와 자연스럽게 연결 */
.bg-purple.py-5:first-child {
    /* sticky navbar 사용으로 margin 조정 불필요 */
}

.hero-section::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-image: 
        radial-gradient(circle at 20% 80%, rgba(81, 43, 212, 0.3) 0%, transparent 50%),
        radial-gradient(circle at 80% 20%, rgba(13, 110, 253, 0.3) 0%, transparent 50%),
        radial-gradient(circle at 40% 40%, rgba(123, 92, 214, 0.2) 0%, transparent 40%);
    pointer-events: none;
}

.hero-overlay {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%23ffffff' fill-opacity='0.03'%3E%3Cpath d='M36 34v-4h-2v4h-4v2h4v4h2v-4h4v-2h-4zm0-30V0h-2v4h-4v2h4v4h2V6h4V4h-4zM6 34v-4H4v4H0v2h4v4h2v-4h4v-2H6zM6 4V0H4v4H0v2h4v4h2V6h4V4H6z'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
    pointer-events: none;
}

.text-gradient {
    background: linear-gradient(90deg, #FFD700 0%, #FF8C00 50%, #FF6B9D 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-info {
    font-size: 1.1rem;
}

.info-item {
    background: rgba(255, 255, 255, 0.1);
    padding: 0.5rem 1rem;
    border-radius: 50px;
    backdrop-filter: blur(10px);
}

/* 카운트다운 */
.countdown-bar {
    background: rgba(0, 0, 0, 0.3);
    backdrop-filter: blur(10px);
    padding: 1rem 0;
}

.countdown-item {
    min-width: 60px;
}

.countdown-number {
    display: block;
    font-size: 2rem;
    font-weight: 700;
    color: white;
    line-height: 1;
}

.countdown-label {
    display: block;
    font-size: 0.75rem;
    color: rgba(255, 255, 255, 0.7);
    text-transform: uppercase;
}

/* 버튼 스타일 */
.btn-primary {
    background: linear-gradient(135deg, var(--purple-primary) 0%, var(--purple-dark) 100%);
    border: none;
    transition: transform 0.2s, box-shadow 0.2s;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 30px rgba(81, 43, 212, 0.4);
    background: linear-gradient(135deg, var(--purple-light) 0%, var(--purple-primary) 100%);
}

.btn-outline-primary {
    border-color: var(--purple-primary);
    color: var(--purple-primary);
}

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

/* 카드 호버 효과 */
.card-hover {
    transition: transform 0.3s, box-shadow 0.3s;
}

.card-hover:hover {
    transform: translateY(-5px);
    box-shadow: 0 15px 40px rgba(0, 0, 0, 0.15);
}

/* 아이콘 박스 */
.icon-box {
    width: 80px;
    height: 80px;
    border-radius: 20px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto;
}

/* 연사 카드 */
.speaker-avatar {
    width: 100px;
    height: 100px;
    margin: 0 auto;
}

.avatar-placeholder {
    width: 100%;
    height: 100%;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
}

/* 카드 이미지 플레이스홀더 */
.card-img-placeholder {
    height: 200px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.bg-gradient-purple {
    background: linear-gradient(135deg, var(--purple-primary) 0%, var(--purple-dark) 100%);
}

.bg-gradient-blue {
    background: linear-gradient(135deg, #0D6EFD 0%, #0B5ED7 100%);
}

.bg-gradient-green {
    background: linear-gradient(135deg, #198754 0%, #146C43 100%);
}

/* 푸터 */
.footer-dark {
    background: linear-gradient(135deg, #1a1a2e 0%, #16213e 100%);
}

.social-links a {
    transition: color 0.2s, transform 0.2s;
}

.social-links a:hover {
    color: white !important;
    transform: translateY(-2px);
}

/* 스폰서 로고 */
.sponsor-logo {
    transition: transform 0.2s;
}

.sponsor-logo:hover {
    transform: scale(1.05);
}

/* 역대 후원사 로고 */
.sponsor-item {
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 1rem 2rem;
    transition: transform 0.2s, opacity 0.2s;
}

.sponsor-item:hover {
    transform: scale(1.1);
}

.sponsor-logo-img {
    max-height: 80px;
    max-width: 220px;
    object-fit: contain;
    filter: grayscale(100%);
    opacity: 0.7;
    transition: filter 0.3s, opacity 0.3s;
}

.sponsor-item:hover .sponsor-logo-img {
    filter: grayscale(0%);
    opacity: 1;
}

.sponsor-fallback {
    width: 220px;
    height: 80px;
    align-items: center;
    justify-content: center;
    text-align: center;
    background: #f8f9fa;
    border-radius: 8px;
    padding: 0.5rem;
    font-size: 0.9rem;
}

/* 후원사 캐러셀 */
.sponsor-carousel {
    position: relative;
}

.sponsor-carousel .carousel-inner {
    padding: 1rem 0;
}

.sponsor-carousel .carousel-item {
    transition: transform 0.8s ease-in-out, opacity 0.8s ease-in-out;
}

.sponsor-carousel .sponsor-page {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    align-items: center;
    gap: 2rem;
    padding: 1rem 4rem;
    min-height: 150px;
}

.sponsor-carousel .carousel-control-prev,
.sponsor-carousel .carousel-control-next {
    width: 50px;
    height: 50px;
    top: 50%;
    transform: translateY(-50%);
    opacity: 1;
    transition: all 0.3s;
}

.sponsor-carousel .carousel-control-prev {
    left: 0;
}

.sponsor-carousel .carousel-control-next {
    right: 0;
}

.sponsor-carousel .carousel-control-prev:hover,
.sponsor-carousel .carousel-control-next:hover {
    transform: translateY(-50%) scale(1.1);
}

.sponsor-carousel .carousel-control-prev-icon,
.sponsor-carousel .carousel-control-next-icon {
    background-color: var(--purple-primary);
    border-radius: 50%;
    width: 40px;
    height: 40px;
    background-size: 40%;
}

.sponsor-carousel .carousel-indicators {
    bottom: -2.5rem;
    margin-bottom: 0;
}

.sponsor-carousel .carousel-indicators button {
    width: 12px;
    height: 12px;
    border-radius: 50%;
    background-color: #ccc;
    border: none;
    margin: 0 6px;
    transition: background-color 0.3s;
}

.sponsor-carousel .carousel-indicators button.active {
    background-color: var(--purple-primary);
}

/* 통계 카드 */
.stat-card {
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid rgba(255, 255, 255, 0.1);
    transition: all 0.3s ease;
}

.stat-card:hover {
    background: rgba(255, 255, 255, 0.1);
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.3);
}

.stat-icon {
    opacity: 0.9;
}

.stat-card:hover .stat-icon {
    transform: scale(1.1);
    transition: transform 0.3s ease;
}

/* 세션 카드 링크 */
.session-card-link {
    transition: all 0.3s ease;
}

.session-card-link:hover {
    transform: translateY(-5px);
    box-shadow: 0 15px 40px rgba(81, 43, 212, 0.15) !important;
}

.session-card-link .card-body:hover .card-title {
    color: var(--purple-primary);
}

/* 아카이브 페이지 */
.event-card {
    transition: all 0.3s;
}

.event-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 20px 50px rgba(81, 43, 212, 0.2);
}

.year-badge {
    font-size: 3rem;
    font-weight: 800;
    background: linear-gradient(135deg, #ffffff 0%, #c0c0c0 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* 반응형 조정 */
@media (max-width: 768px) {
    .hero-section h1 {
        font-size: 2.5rem !important;
    }
    
    .countdown-number {
        font-size: 1.5rem;
    }
    
    .hero-info {
        font-size: 0.9rem;
    }
}

/* 포커스 스타일 */
.btn:focus, .btn:active:focus, .btn-link.nav-link:focus, .form-control:focus, .form-check-input:focus {
    box-shadow: 0 0 0 0.1rem white, 0 0 0 0.25rem var(--purple-primary);
}

/* 폼 스타일 */
.form-floating > .form-control-plaintext::placeholder, .form-floating > .form-control::placeholder {
    color: var(--bs-secondary-color);
    text-align: end;
}

.form-floating > .form-control-plaintext:focus::placeholder, .form-floating > .form-control:focus::placeholder {
    text-align: start;
}

/* 메인 페이지 추가 스타일 */
.text-purple {
    color: var(--purple-primary) !important;
}

.bg-purple {
    background: linear-gradient(135deg, var(--purple-primary) 0%, var(--purple-dark) 100%) !important;
}

.bg-gradient-purple {
    background: linear-gradient(135deg, var(--purple-primary) 0%, var(--purple-dark) 100%);
}

/* 히어로 통계 */
.hero-stats .stat-item {
    background: rgba(255, 255, 255, 0.1);
    padding: 1rem 1.5rem;
    border-radius: 12px;
    backdrop-filter: blur(10px);
}

/* 플로팅 테크 뱃지 */
.floating-cards {
    animation: float 6s ease-in-out infinite;
}

.tech-badge {
    display: inline-block;
    font-weight: 500;
    transition: transform 0.3s;
}

.tech-badge:hover {
    transform: scale(1.05);
}

@keyframes float {
    0%, 100% { transform: translateY(0px); }
    50% { transform: translateY(-20px); }
}

/* 작은 아이콘 */
.icon-sm {
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

/* 다크 카드 호버 */
.card-hover-dark {
    transition: all 0.3s;
    cursor: pointer;
}

.card-hover-dark:hover {
    transform: translateY(-5px);
    border-color: var(--purple-primary) !important;
    box-shadow: 0 10px 30px rgba(81, 43, 212, 0.3);
}

/* 타임라인 히스토리 */
.timeline-horizontal {
    position: relative;
}

/* 연사 링크 */
.speaker-link {
    transition: all 0.2s;
}

.speaker-link:hover {
    transform: translateY(-2px);
    opacity: 0.9;
}

.speaker-link:hover .speaker-avatar {
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.2);
}

/* 세션 링크 카드 (연사 모달 내) */
.session-link-card {
    transition: all 0.2s;
}

.session-link-card:hover {
    transform: translateX(5px);
    background-color: #e9ecef !important;
}

/* 뱃지 스타일 */
.badge.bg-purple {
    background: var(--purple-primary) !important;
}

/* 연사 아바타 */
.speaker-avatar-wrapper {
    position: relative;
    border-radius: 50%;
    overflow: hidden;
}

.speaker-avatar {
    object-fit: cover;
    background-color: #f8f9fa;
}

.speaker-avatar-wrapper .avatar-placeholder {
    position: absolute;
    top: 0;
    left: 0;
}

/* 반응형 히어로 통계 */
@media (max-width: 992px) {
    .hero-stats {
        justify-content: center !important;
    }
    
    .hero-stats .stat-item {
        padding: 0.75rem 1rem;
    }
    
    .hero-stats .display-5 {
        font-size: 1.5rem !important;
    }
}

@media (max-width: 576px) {
    .hero-stats .stat-item {
        flex: 0 0 45%;
    }
}

/* 그라데이션 배경 */
.bg-gradient-purple-light {
    background: linear-gradient(135deg, var(--purple-primary) 0%, #7B68EE 50%, #9370DB 100%);
}