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

html {
    background: linear-gradient(135deg, #0f0f23 0%, #1a1a2e 50%, #16213e 100%);
    background-attachment: fixed;
    min-height: 100%;
    height: 100%;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen', 'Ubuntu', 'Cantarell', 'Noto Sans KR', sans-serif;
    background: linear-gradient(135deg, #0f0f23 0%, #1a1a2e 50%, #16213e 100%);
    background-attachment: fixed;
    color: #e0e0e0;
    line-height: 1.6;
    min-height: 100vh;
    position: relative;
    overflow-x: hidden;
    padding-top: 60px;
    padding-bottom: 60px;
}

body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(135deg, #0f0f23 0%, #1a1a2e 50%, #16213e 100%);
    z-index: -1;
    pointer-events: none;
}

/* 애니메이션 효과 */
@keyframes float {
    0%, 100% { transform: translateY(0px) rotate(0deg); }
    50% { transform: translateY(-20px) rotate(5deg); }
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes gradient {
    0% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
    100% { background-position: 0% 50%; }
}

/* Header */
.header {
    background: rgba(15, 15, 35, 0.95);
    backdrop-filter: blur(20px);
    color: #e0e0e0;
    padding: 12px 0;
    box-shadow: 0 4px 30px rgba(0, 0, 0, 0.8), 0 2px 10px rgba(0, 0, 0, 0.5);
    border-bottom: 2px solid rgba(102, 126, 234, 0.3);
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    width: 100%;
    z-index: 1000;
    transition: all 0.3s ease;
}

.header-container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 30px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    margin: 0;
    font-size: 28px;
    font-weight: 800;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    letter-spacing: 2px;
    position: relative;
    animation: fadeInUp 0.6s ease;
}

.register-btn {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    text-decoration: none;
    padding: 12px 24px;
    border-radius: 8px;
    font-weight: 600;
    font-size: 14px;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px rgba(102, 126, 234, 0.4);
    border: none;
    cursor: pointer;
}

.register-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(102, 126, 234, 0.6);
}

/* 인증 관련 스타일 */
.auth-nav {
    display: flex;
    align-items: center;
    gap: 12px;
    position: relative;
}

.user-info {
    display: flex;
    align-items: center;
    position: relative;
}

/* 햄버거 메뉴 토글 버튼 */
.menu-toggle {
    background: #2a2a3e;
    border: 1px solid #3a3a4e;
    border-radius: 8px;
    width: 44px;
    height: 44px;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    gap: 5px;
    cursor: pointer;
    transition: all 0.2s ease;
    padding: 0;
    position: relative;
    z-index: 1001;
}

.menu-toggle span {
    width: 20px;
    height: 2px;
    background: #ffffff;
    border-radius: 2px;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    display: block;
}

.menu-toggle:hover {
    background: #34344a;
    border-color: #4a4a5e;
    transform: scale(1.05);
}

.menu-toggle.active {
    background: #4a3d6e;
    border-color: #667eea;
}

.menu-toggle.active span:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
}

.menu-toggle.active span:nth-child(2) {
    opacity: 0;
    transform: translateX(-10px);
}

.menu-toggle.active span:nth-child(3) {
    transform: rotate(-45deg) translate(5px, -5px);
}

/* 드롭다운 메뉴 */
.dropdown-menu {
    position: absolute;
    top: calc(100% + 8px);
    right: 0;
    background: #1a1a2e;
    border: 1px solid #2a2a3e;
    border-radius: 8px;
    min-width: 240px;
    box-shadow: 0 12px 48px rgba(0, 0, 0, 0.8);
    opacity: 0;
    visibility: hidden;
    transform: translateY(-8px) scale(0.95);
    transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    z-index: 1000;
    overflow: hidden;
}

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

.dropdown-header {
    padding: 18px 20px 16px;
    border-bottom: 1px solid #2a2a3e;
}

.dropdown-header span {
    color: #ffffff;
    font-weight: 600;
    font-size: 16px;
    display: block;
}

.dropdown-divider {
    height: 1px;
    background: #2a2a3e;
    margin: 0;
}

.dropdown-item {
    display: flex;
    align-items: center;
    gap: 14px;
    padding: 16px 20px;
    color: #e0e0e0;
    text-decoration: none;
    font-size: 15px;
    font-weight: 500;
    transition: all 0.15s ease;
    background: transparent;
    border: none;
    width: 100%;
    cursor: pointer;
    text-align: left;
    position: relative;
}

.dropdown-item::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 3px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    opacity: 0;
    transition: opacity 0.15s ease;
}

.dropdown-item:hover {
    background: #2a2a3e;
    color: #ffffff;
}

.dropdown-item:hover::before {
    opacity: 1;
}

.dropdown-item.logout-item {
    color: #f5576c;
}

.dropdown-item.logout-item::before {
    background: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
}

.dropdown-item.logout-item:hover {
    background: #3a1f2a;
    color: #ff6b7d;
}

.dropdown-icon {
    font-size: 18px;
    width: 24px;
    height: 24px;
    text-align: center;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
    color: #9a9aaf;
    transition: all 0.15s ease;
}

.dropdown-item:hover .dropdown-icon {
    color: #ffffff;
    transform: scale(1.1);
}

.dropdown-item.logout-item .dropdown-icon {
    color: #d94a5f;
}

.dropdown-item.logout-item:hover .dropdown-icon {
    color: #ff6b7d;
}

.guest-nav {
    display: flex;
    align-items: center;
    gap: 10px;
}

.login-btn {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    text-decoration: none;
    padding: 10px 20px;
    border-radius: 8px;
    font-weight: 600;
    font-size: 13px;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px rgba(102, 126, 234, 0.3);
}

.login-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(102, 126, 234, 0.5);
}

/* Hero Section */
.hero-section {
    position: relative;
    padding: 100px 0 120px;
    overflow: hidden;
}

.hero-container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 30px;
    position: relative;
    z-index: 2;
}

.hero-content {
    text-align: center;
    max-width: 900px;
    margin: 0 auto;
    animation: fadeInUp 0.8s ease;
}

.hero-title {
    font-size: 64px;
    font-weight: 800;
    line-height: 1.2;
    margin-bottom: 30px;
    color: #ffffff;
}

.gradient-text {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 50%, #f093fb 100%);
    background-size: 200% 200%;
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    animation: gradient 3s ease infinite;
}

.hero-description {
    font-size: 20px;
    color: rgba(255, 255, 255, 0.8);
    margin-bottom: 50px;
    line-height: 1.8;
}

.hero-stats {
    display: flex;
    justify-content: center;
    gap: 60px;
    margin-top: 60px;
}

.stat-item {
    text-align: center;
}

.stat-number {
    font-size: 48px;
    font-weight: 800;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 10px;
}

.stat-label {
    font-size: 16px;
    color: rgba(255, 255, 255, 0.7);
    font-weight: 500;
}

/* Hero Decoration */
.hero-decoration {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 1;
}

.floating-shape {
    position: absolute;
    border-radius: 50%;
    opacity: 0.1;
    animation: float 6s ease-in-out infinite;
}

.shape-1 {
    width: 300px;
    height: 300px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    top: 10%;
    left: 10%;
    animation-delay: 0s;
}

.shape-2 {
    width: 200px;
    height: 200px;
    background: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
    top: 60%;
    right: 15%;
    animation-delay: 2s;
}

.shape-3 {
    width: 150px;
    height: 150px;
    background: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
    bottom: 20%;
    left: 20%;
    animation-delay: 4s;
}

/* Projects Section */
.projects-section {
    padding: 40px 0 40px;
    position: relative;
}

.projects-container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 30px;
}

.section-header {
    text-align: center;
    margin-bottom: 50px;
    animation: fadeInUp 0.8s ease;
}

.section-title {
    font-size: 42px;
    font-weight: 800;
    color: #ffffff;
}

.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 30px;
    margin-bottom: 50px;
}

/* Project Card */
.project-card {
    background: rgba(255, 255, 255, 0.05);
    backdrop-filter: blur(10px);
    border-radius: 8px;
    border: 1px solid rgba(255, 255, 255, 0.1);
    overflow: hidden;
    transition: all 0.3s ease;
    cursor: pointer;
    text-decoration: none;
    color: inherit;
    position: relative;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.3);
    animation: fadeInUp 0.6s ease;
}

.project-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 12px 40px rgba(0, 0, 0, 0.4);
    border-color: rgba(255, 255, 255, 0.2);
}

.project-content {
    padding: 30px;
    position: relative;
    z-index: 2;
    min-height: 180px;
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.project-category-badge {
    position: absolute;
    top: 20px;
    right: 20px;
    padding: 8px 16px;
    border-radius: 6px;
    color: white;
    font-size: 12px;
    font-weight: 700;
    background: rgba(255, 255, 255, 0.15);
    text-align: center;
    z-index: 3;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.2);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.project-title {
    font-size: 22px;
    font-weight: 700;
    color: #ffffff;
    margin: 0 0 12px 0;
    line-height: 1.4;
    position: relative;
    z-index: 2;
}

.project-description {
    font-size: 15px;
    color: #b0b0c0;
    line-height: 1.6;
    margin: 0;
    position: relative;
    z-index: 2;
    display: -webkit-box;
    -webkit-line-clamp: 3;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

/* Empty State */
.empty-state {
    text-align: center;
    padding: 80px 20px;
    animation: fadeInUp 0.8s ease;
}

.empty-icon {
    font-size: 80px;
    margin-bottom: 20px;
    opacity: 0.5;
}

.empty-state h3 {
    font-size: 28px;
    font-weight: 700;
    color: #ffffff;
    margin-bottom: 10px;
}

.empty-state p {
    font-size: 16px;
    color: #9a9aaf;
}

/* Footer */
.footer {
    background: #0f0f23;
    color: #e0e0e0;
    padding: 30px 0;
    text-align: center;
    border-top: 1px solid #1a1a2e;
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    width: 100%;
    z-index: 1000;
}

.footer-container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 30px;
}

.footer p {
    opacity: 0.7;
    font-size: 14px;
}

/* 반응형 디자인 */
@media (max-width: 1024px) {
    .hero-title {
        font-size: 48px;
    }
    
    .section-title {
        font-size: 36px;
    }
    
    .projects-grid {
        grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
        gap: 25px;
    }
    
    .hero-stats {
        gap: 40px;
    }
    
    .stat-number {
        font-size: 36px;
    }
}

@media (max-width: 768px) {
    body {
        padding-top: 70px;
        padding-bottom: 70px;
    }
    
    .header {
        padding: 10px 0;
    }
    
    .header-container {
        padding: 0 20px;
    }
    
    .logo {
        font-size: 28px;
        letter-spacing: 2px;
    }
    
    .register-btn, .login-btn {
        padding: 10px 18px;
        font-size: 12px;
    }
    
    .footer {
        padding: 20px 0;
    }
    
    .hero-section {
        padding: 60px 0 80px;
    }
    
    .hero-title {
        font-size: 36px;
    }
    
    .hero-description {
        font-size: 16px;
        margin-bottom: 40px;
    }
    
    .hero-stats {
        flex-direction: column;
        gap: 30px;
        margin-top: 40px;
    }
    
    .stat-number {
        font-size: 32px;
    }
    
    .projects-section {
        padding: 30px 0 30px;
    }
    
    .section-title {
        font-size: 32px;
    }
    
    .section-header {
        margin-bottom: 40px;
    }
    
    .projects-grid {
        grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
        gap: 20px;
    }
    
    .project-content {
        padding: 25px;
        min-height: 160px;
    }
    
    .project-title {
        font-size: 20px;
    }
    
    .project-description {
        font-size: 14px;
    }
    
    .shape-1, .shape-2, .shape-3 {
        display: none;
    }
}

@media (max-width: 480px) {
    body {
        padding-top: 100px;
        padding-bottom: 80px;
    }
    
    .header {
        padding: 12px 0;
    }
    
    .header-container {
        flex-direction: column;
        gap: 15px;
        padding: 0 20px;
    }
    
    .auth-nav {
        width: 100%;
        justify-content: center;
    }
    
    .menu-toggle {
        width: 40px;
        height: 40px;
    }
    
    .menu-toggle span {
        width: 20px;
    }
    
    .dropdown-menu {
        min-width: 200px;
        right: 0;
    }
    
    .footer {
        padding: 15px 0;
    }
    
    .footer p {
        font-size: 12px;
    }
    
    .hero-title {
        font-size: 28px;
    }
    
    .hero-description {
        font-size: 14px;
    }
    
    .section-title {
        font-size: 28px;
    }
    
    .projects-section {
        padding: 20px 0 20px;
    }
    
    .projects-grid {
        grid-template-columns: 1fr;
        gap: 20px;
    }
    
    .project-content {
        padding: 20px;
        min-height: 140px;
    }
    
    .project-title {
        font-size: 18px;
    }
    
    .project-description {
        font-size: 13px;
    }
}

/* 라이트 모드 - 깔끔한 디자인 */
html.light-mode {
    background: #f8f9fa;
    background-attachment: fixed;
}

body.light-mode {
    background: #f8f9fa;
    background-attachment: fixed;
    color: #212529;
}

body.light-mode::before {
    background: #f8f9fa;
}

body.light-mode .header {
    background: #ffffff;
    color: #212529;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.08);
    border-bottom: 1px solid #e9ecef;
}

body.light-mode .logo {
    color: #495057;
    background: none;
    -webkit-background-clip: unset;
    -webkit-text-fill-color: #495057;
    background-clip: unset;
}

body.light-mode .menu-toggle {
    background: #f8f9fa;
    border: 1px solid #dee2e6;
}

body.light-mode .menu-toggle span {
    background: #495057;
}

body.light-mode .menu-toggle:hover {
    background: #e9ecef;
    border-color: #ced4da;
}

body.light-mode .menu-toggle.active {
    background: #e9ecef;
    border-color: #667eea;
}

body.light-mode .menu-toggle.active span {
    background: #667eea;
}

body.light-mode .dropdown-menu {
    background: #ffffff;
    border: 1px solid #e9ecef;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

body.light-mode .dropdown-header {
    color: #212529;
    border-bottom: 1px solid #e9ecef;
}

body.light-mode .dropdown-item {
    color: #212529;
}

body.light-mode .dropdown-item:hover {
    background: #f8f9fa;
}

body.light-mode .dropdown-divider {
    background: #dee2e6;
}

body.light-mode .dropdown-icon {
    color: #495057;
}

body.light-mode .dropdown-item:hover .dropdown-icon {
    color: #667eea;
}

body.light-mode .dropdown-item.logout-item {
    color: #dc3545;
}

body.light-mode .dropdown-item.logout-item .dropdown-icon {
    color: #dc3545;
}

body.light-mode .dropdown-item.logout-item:hover {
    background: #fff5f5;
    color: #c82333;
}

body.light-mode .dropdown-item.logout-item:hover .dropdown-icon {
    color: #c82333;
}

body.light-mode .dropdown-header span {
    color: #212529;
}

body.light-mode .section-title {
    color: #212529;
}

body.light-mode .project-card {
    background: #ffffff;
    border: 1px solid #e9ecef;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.04);
}

body.light-mode .project-card:hover {
    border-color: #667eea;
    box-shadow: 0 4px 16px rgba(102, 126, 234, 0.12);
    transform: translateY(-2px);
}

body.light-mode .project-title {
    color: #212529;
}

body.light-mode .project-description {
    color: #6c757d;
}

body.light-mode .project-category-badge {
    background: #f0f4ff;
    color: #667eea;
    border: 1px solid #e0e7ff;
}

body.light-mode .footer {
    background: #ffffff;
    color: #6c757d;
    border-top: 1px solid #e9ecef;
    box-shadow: 0 -1px 3px rgba(0, 0, 0, 0.08);
}

body.light-mode .empty-state {
    color: #6c757d;
}

body.light-mode .empty-state h3 {
    color: #212529;
}

body.light-mode .login-btn,
body.light-mode .register-btn {
    background: transparent;
    color: #495057;
    box-shadow: none;
    border: none;
    padding: 10px 20px;
}

body.light-mode .login-btn:hover,
body.light-mode .register-btn:hover {
    background: transparent;
    color: #212529;
    box-shadow: none;
    transform: none;
}

/* 테마 토글 버튼 */
.theme-toggle {
    background: #2a2a3e;
    border: 1px solid #3a3a4e;
    border-radius: 8px;
    width: 44px;
    height: 44px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all 0.3s ease;
    padding: 0;
    margin-left: 10px;
    font-size: 20px;
}

.theme-toggle:hover {
    background: #34344a;
    border-color: #4a4a5e;
    transform: scale(1.05);
}

body.light-mode .theme-toggle {
    background: #f8f9fa;
    border: 1px solid #dee2e6;
    color: #495057;
}

body.light-mode .theme-toggle:hover {
    background: #e9ecef;
    border-color: #ced4da;
}