/* 기본 스타일 초기화 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #f8f9fa;
}

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

/* 헤더 스타일 */
.header {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 1rem 0;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

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

.logo {
    font-size: 1.8rem;
    font-weight: bold;
}

.nav ul {
    display: flex;
    list-style: none;
    gap: 2rem;
}

.nav-link {
    color: white;
    text-decoration: none;
    padding: 0.5rem 1rem;
    border-radius: 5px;
    transition: background-color 0.3s ease;
}

.nav-link:hover,
.nav-link.active {
    background-color: rgba(255,255,255,0.2);
}

/* 메인 콘텐츠 */
.main {
    margin-top: 80px;
    min-height: calc(100vh - 80px);
}

.section {
    display: none;
    padding: 2rem 0;
}

.section.active {
    display: block;
}

/* 히어로 섹션 */
.hero {
    text-align: center;
    padding: 4rem 0;
    background: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
    color: white;
    margin-bottom: 3rem;
    border-radius: 10px;
}

.hero h2 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.hero p {
    font-size: 1.2rem;
    margin-bottom: 2rem;
    opacity: 0.9;
}

.hero-buttons {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
}

/* 버튼 스타일 */
.btn {
    display: inline-block;
    padding: 12px 24px;
    text-decoration: none;
    border-radius: 5px;
    font-weight: bold;
    transition: all 0.3s ease;
    border: none;
    cursor: pointer;
    font-size: 1rem;
}

.btn-primary {
    background-color: #007bff;
    color: white;
}

.btn-primary:hover {
    background-color: #0056b3;
    transform: translateY(-2px);
}

.btn-secondary {
    background-color: transparent;
    color: white;
    border: 2px solid white;
}

.btn-secondary:hover {
    background-color: white;
    color: #333;
}

/* 기능 카드 */
.features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-bottom: 3rem;
}

.feature-card {
    background: white;
    padding: 2rem;
    border-radius: 10px;
    text-align: center;
    box-shadow: 0 5px 15px rgba(0,0,0,0.1);
    transition: transform 0.3s ease;
}

.feature-card:hover {
    transform: translateY(-5px);
}

.feature-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.feature-card h3 {
    margin-bottom: 1rem;
    color: #333;
}

/* 프로젝트 그리드 */
.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 2rem;
}

.project-card {
    background: white;
    border-radius: 10px;
    padding: 2rem;
    box-shadow: 0 5px 15px rgba(0,0,0,0.1);
    transition: transform 0.3s ease;
}

.project-card:hover {
    transform: translateY(-5px);
}

.project-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
}

.project-header h3 {
    color: #333;
}

.project-status {
    background-color: #28a745;
    color: white;
    padding: 0.25rem 0.75rem;
    border-radius: 15px;
    font-size: 0.8rem;
    font-weight: bold;
}

.project-card p {
    margin-bottom: 1.5rem;
    color: #666;
}

.project-lessons,
.project-features {
    margin-bottom: 1.5rem;
}

.project-lessons h4,
.project-features h4 {
    margin-bottom: 0.5rem;
    color: #333;
}

.project-lessons ul,
.project-features ul {
    list-style: none;
    padding-left: 0;
}

.project-lessons li,
.project-features li {
    padding: 0.25rem 0;
    color: #666;
}

.project-lessons a {
    color: #007bff;
    text-decoration: none;
}

.project-lessons a:hover {
    text-decoration: underline;
}

/* 소개 섹션 */
.about-content {
    background: white;
    padding: 2rem;
    border-radius: 10px;
    box-shadow: 0 5px 15px rgba(0,0,0,0.1);
}

.about-text h3 {
    margin: 2rem 0 1rem 0;
    color: #333;
}

.about-text h3:first-child {
    margin-top: 0;
}

.about-text p {
    margin-bottom: 1rem;
    color: #666;
}

.about-text ol {
    margin-left: 2rem;
    margin-bottom: 1rem;
}

.about-text li {
    margin-bottom: 0.5rem;
    color: #666;
}

/* 푸터 */
.footer {
    background-color: #333;
    color: white;
    text-align: center;
    padding: 2rem 0;
    margin-top: 3rem;
}

/* 반응형 디자인 */
@media (max-width: 768px) {
    .header .container {
        flex-direction: column;
        gap: 1rem;
    }
    
    .nav ul {
        gap: 1rem;
    }
    
    .hero h2 {
        font-size: 2rem;
    }
    
    .hero-buttons {
        flex-direction: column;
        align-items: center;
    }
    
    .features {
        grid-template-columns: 1fr;
    }
    
    .projects-grid {
        grid-template-columns: 1fr;
    }
    
    .project-header {
        flex-direction: column;
        align-items: flex-start;
        gap: 0.5rem;
    }
    
    .container {
        padding: 0 15px;
    }
}

@media (max-width: 480px) {
    .hero h2 {
        font-size: 1.5rem;
    }
    
    .hero p {
        font-size: 1rem;
    }
    
    .feature-card,
    .project-card {
        padding: 1.5rem;
    }
    
    .btn {
        padding: 10px 20px;
        font-size: 0.9rem;
    }
}

/* 애니메이션 */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.section.active {
    animation: fadeIn 0.5s ease-in-out;
}

/* 스크롤바 스타일 */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: #f1f1f1;
}

::-webkit-scrollbar-thumb {
    background: #888;
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: #555;
}