@import url('https://fonts.googleapis.com/css2?family=Poppins:wght@300;400;600;700&display=swap');

        body {
            font-family: 'Poppins', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
            line-height: 1.6;
            margin: 0;
            padding: 0;
            background-color: #1a1a1a;
            color: #ffffff;
            position: relative;
            min-height: 100vh;
            display: flex;
            align-items: center;
            justify-content: center;
        }

        #background-canvas {
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            z-index: -1;
        }

        /* 컨테이너 스타일 */
        .container {
            max-width: 800px;
            background: rgba(255, 255, 255, 0.1);
            backdrop-filter: blur(20px);
            -webkit-backdrop-filter: blur(20px);
            border: 1px solid rgba(255, 255, 255, 0.2);
            padding: 30px;
            border-radius: 5px;
            box-shadow: 0 8px 32px rgba(0, 0, 0, 0.3);
            width: 90%;
        }

        h1 {
            color: #ffffff;
            text-align: center;
            font-size: 3.5em;
            font-weight: 700;
            margin-bottom: 2rem;
            letter-spacing: 0.1em;
            text-shadow: 0 0 20px rgba(255, 255, 255, 0.3);
            transition: all 0.3s ease;
        }

        h1:hover {
            text-shadow: 0 0 30px rgba(255, 255, 255, 0.5);
            transform: scale(1.05);
        }

        .section {
            margin: 2.5rem 0;
            text-align: center;
            font-size: 1.3em;
            font-weight: 300;
            color: rgba(255, 255, 255, 0.9);
            letter-spacing: 0.05em;
            position: relative;
            padding: 1rem 0;
        }

        .section:not(#userSection):not(:last-child)::after {
            content: '';
            position: absolute;
            bottom: -0.75rem;
            left: 50%;
            transform: translateX(-50%);
            width: 60px;
            height: 1px;
            background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.5), transparent);
        }


        .section h2 {
            color: #cccccc;
            border-bottom: 2px solid #666;
            padding-bottom: 5px;
            font-size: 1.5em;
        }

        /* 확장 컨텐츠 스타일 */
        .expanded-content {
            margin-top: 2rem;
            padding-top: 2rem;
            border-top: 1px solid rgba(255, 255, 255, 0.2);
            opacity: 0;
            overflow: hidden;
            max-height: 0;
            transform: translateY(-15px) scale(0.98);
            transition: all 0.6s cubic-bezier(0.23, 1, 0.32, 1);
        }

        .expanded-content.show {
            opacity: 1;
            max-height: 1000px;
            transform: translateY(0) scale(1);
        }


        /* 각 섹션별 애니메이션 */
        .content-section {
            margin-bottom: 2rem;
            padding: 2rem;
            background: rgba(255, 255, 255, 0.05);
            border-radius: 10px;
            border: 1px solid rgba(255, 255, 255, 0.1);
        }

        /* CONTENT 타이틀 스타일 */
        .content-title {
            text-align: center;
            color: #ffffff;
            font-size: 1.8em;
            font-weight: 600;
            margin: 0 0 2rem 0;
            letter-spacing: 0.2em;
            text-shadow: 0 0 15px rgba(255, 255, 255, 0.3);
            position: relative;
        }

        .content-title::after {
            content: '';
            position: absolute;
            bottom: -0.5rem;
            left: 50%;
            transform: translateX(-50%);
            width: 80px;
            height: 2px;
            background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.6), transparent);
        }

        /* 컨텐츠 메뉴 그리드 */
        .content-menu {
            display: grid;
            grid-template-columns: repeat(4, 1fr);
            gap: 15px;
        }

        /* 컨텐츠 버튼 스타일 */
        .content-btn {
            display: flex;
            align-items: center;
            justify-content: center;
            padding: 15px 10px;
            background: rgba(255, 255, 255, 0.08);
            border: 1px solid rgba(255, 255, 255, 0.15);
            border-radius: 8px;
            color: #ffffff;
            text-decoration: none;
            font-size: 0.9em;
            font-weight: 500;
            text-align: center;
            transition: all 0.3s cubic-bezier(0.25, 0.46, 0.45, 0.94);
            backdrop-filter: blur(10px);
            -webkit-backdrop-filter: blur(10px);
            min-height: 50px;
            position: relative;
            overflow: hidden;
        }

        .content-btn::before {
            content: '';
            position: absolute;
            top: 0;
            left: -100%;
            width: 100%;
            height: 100%;
            background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.1), transparent);
            transition: left 0.5s ease;
        }

        .content-btn:hover {
            background: rgba(255, 255, 255, 0.15);
            border-color: rgba(255, 255, 255, 0.3);
            transform: translateY(-3px);
            box-shadow: 0 8px 25px rgba(0, 0, 0, 0.3);
            color: #ffffff;
            text-shadow: 0 0 10px rgba(255, 255, 255, 0.5);
        }

        .content-btn:hover::before {
            left: 100%;
        }

        /* 반응형 디자인 */
        @media (max-width: 768px) {
            .content-menu {
                grid-template-columns: repeat(2, 1fr);
                gap: 12px;
            }
            
            .content-btn {
                font-size: 0.8em;
                padding: 12px 8px;
                min-height: 45px;
            }
            
            .content-title {
                font-size: 1.5em;
                margin-bottom: 1.5rem;
            }
        }

        @media (max-width: 480px) {
            .content-menu {
                grid-template-columns: 1fr;
                gap: 10px;
            }
            
            .content-section {
                padding: 1.5rem;
            }
            
            .content-title {
                font-size: 1.3em;
                margin-bottom: 1.2rem;
            }
        }


        /* 사용자 섹션 스타일 */
        #userSection {
            display: flex;
            flex-direction: column;
            align-items: center;
            gap: 0;
        }

        /* 확장 텍스트 스타일 */
        .expand-text {
            transition: color 0.3s ease;
        }

        .expand-text:hover {
            color: rgba(255, 255, 255, 1) !important;
        }

        @media (max-width: 768px) {
            body {
                padding: 10px;
            }
            .container {
                width: 95%;
                padding: 15px;
            }
            h1 {
                font-size: 2.5em;
            }
            .section h2 {
                font-size: 1.2em;
            }
        }

        @media (max-width: 480px) {
            body {
                padding: 5px;
            }
            .container {
                width: 98%;
                padding: 10px;
            }
            h1 {
                font-size: 2em;
            }
            .section h2 {
                font-size: 1.1em;
            }
            .section {
                margin: 15px 0;
            }
        }