* {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            font-family: 'Pretendard', -apple-system, BlinkMacSystemFont, system-ui, Roboto, sans-serif;
            color: #333;
        }

        body {
            line-height: 1.6;
            background-color: #f9f9f9;
        }

        a {
            text-decoration: none;
            color: inherit;
        }

        ul {
            list-style: none;
        }

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

        section {
            padding: 80px 0;
        }

        .title-area {
            text-align: center;
            margin-bottom: 50px;
        }

        .title-area h2 {
            font-size: 2.5rem;
            margin-bottom: 15px;
            color: #222;
        }

        .title-area p {
            color: #666;
            font-size: 1.1rem;
        }

        /* --- 헤더 --- */
        header {
            position: fixed;
            top: 0;
            width: 100%;
            background: rgba(255, 255, 255, 0.95);
            backdrop-filter: blur(10px);
            border-bottom: 1px solid #eee;
            z-index: 1000;
            height: 70px;
            display: flex;
            align-items: center;
        }

        .header-inner {
            display: flex;
            justify-content: space-between;
            align-items: center;
            width: 100%;
            max-width: 1200px;
            margin: 0 auto;
            padding: 0 20px;
        }

        .logo a {
            font-size: 1.5rem;
            font-weight: 700;
            color: #000;
        }

        .nav-menu ul {
            display: flex;
            gap: 30px;
        }

        .nav-menu a {
            font-weight: 500;
            font-size: 1rem;
            transition: color 0.3s;
        }

        .nav-menu a:hover {
            color: #007bff;
        }

        /* --- Hero 섹션 --- */
        .hero-section {
            height: 100vh;
            display: flex;
            align-items: center;
            justify-content: center;
            text-align: center;
            background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
            padding-top: 70px;
        }

        .hero-text h1 {
            font-size: 3rem;
            line-height: 1.3;
            margin-bottom: 20px;
        }

        .highlight {
            color: #007bff;
        }

        .subtitle {
            font-size: 1.2rem;
            color: #555;
            margin-bottom: 40px;
        }

        .btn-primary {
            display: inline-block;
            background: #007bff;
            color: white;
            padding: 12px 30px;
            border-radius: 30px;
            font-weight: 600;
            transition: background 0.3s;
        }

        .btn-primary:hover {
            background: #0056b3;
        }

        /* --- About & Tech Stack --- */
        .about-content {
            text-align: center;
            max-width: 800px;
            margin: 0 auto;
        }

        .education-box {
            background: white;
            padding: 20px;
            border-radius: 10px;
            box-shadow: 0 4px 15px rgba(0,0,0,0.05);
            margin-top: 30px;
            display: inline-block;
            text-align: left;
        }
        
        .education-box h3 { font-size: 1.2rem; margin-bottom: 5px; }
        .education-box span { color: #777; font-size: 0.9rem; }

        /* Tech Stack 배지 스타일 */
        .tech-stack-container {
            margin-top: 40px;
        }
        .stack-category {
            margin-bottom: 20px;
        }
        .stack-category h4 {
            margin-bottom: 10px;
            font-size: 1rem;
            color: #555;
        }
        .stack-badges img {
            height: 28px;
            margin: 0 4px 5px 0;
        }

        /* --- Grid Layout (Activities & Projects) --- */
        .grid-wrapper {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(320px, 1fr)); /* 가로 배치 핵심 */
            gap: 24px;
        }

        .card {
            background: white;
            border-radius: 12px;
            overflow: hidden;
            box-shadow: 0 5px 15px rgba(0,0,0,0.05);
            transition: transform 0.3s ease;
            display: flex;
            flex-direction: column;
            border: 1px solid #eee;
        }

        .card:hover {
            transform: translateY(-5px);
            box-shadow: 0 10px 25px rgba(0,0,0,0.1);
        }

        /* Activities Card 스타일 (텍스트 위주) */
        .activity-card {
            padding: 30px;
        }
        .activity-card .date {
            display: inline-block;
            font-size: 0.85rem;
            color: #007bff;
            font-weight: 600;
            margin-bottom: 10px;
            background: #e7f1ff;
            padding: 4px 10px;
            border-radius: 4px;
        }
        .activity-card h3 {
            font-size: 1.3rem;
            margin-bottom: 10px;
        }
        .activity-card p {
            color: #666;
            font-size: 0.95rem;
            line-height: 1.6;
        }

        /* Projects Card 스타일 (이미지 포함) */
        .project-card .card-img {
            width: 100%;
            height: 200px;
            object-fit: cover;
            border-bottom: 1px solid #eee;
        }

        .project-card .txtbox {
            padding: 25px;
        }
        .project-card .date {
            font-size: 0.85rem;
            color: #888;
            margin-bottom: 8px;
            display: block;
        }
        .project-card h3 {
            font-size: 1.2rem;
            margin-bottom: 10px;
        }
        .project-card p {
            font-size: 0.95rem;
            color: #555;
            margin-bottom: 15px;
        }
        .repo-link {
            display: inline-block;
            font-size: 0.9rem;
            color: #007bff;
            font-weight: 600;
        }

        /* --- Footer --- */
        footer {
            background: #222;
            color: #fff;
            padding: 50px 0;
            text-align: center;
        }

        footer p { color: #888; margin-bottom: 20px; }

        .social-links {
            display: flex;
            justify-content: center;
            gap: 20px;
        }

        .social-links a {
            color: white;
            padding: 10px 20px;
            border: 1px solid #444;
            border-radius: 5px;
            transition: all 0.3s;
        }

        .social-links a:hover {
            background: white;
            color: #222;
        }

        /* --- 모바일 대응 --- */
        @media (max-width: 768px) {
            .hero-text h1 { font-size: 2rem; }
            .nav-menu { display: none; } /* 심플하게 모바일 메뉴 숨김 처리 (추후 추가 가능) */
            .grid-wrapper { grid-template-columns: 1fr; }
        }