/* --- CSS 변수 및 기본 스타일 --- */
        :root {
            --primary-color: #6a11cb;
            --primary-gradient: linear-gradient(45deg, #6a11cb, #2575fc);
            --secondary-color: #f4f7fc;
            --text-color: #333;
            --light-gray-color: #e0e0e0;
            --white-color: #ffffff;
            --font-family: 'Pretendard', sans-serif;
            --sidebar-width: 260px;
            --danger-color: #dc3545;
            --success-color: #198754;
        }

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

        body {
            font-family: var(--font-family);
            background-color: var(--secondary-color);
            color: var(--text-color);
            display: flex;
            height: 100vh;
            overflow: hidden;
        }

        /* --- 사이드바 (표준 스타일) --- */
        #sidebar {
            width: var(--sidebar-width);
            background: var(--white-color);
            color: var(--text-color);
            display: flex;
            flex-direction: column;
            border-right: 1px solid var(--light-gray-color);
            transition: transform 0.3s ease-in-out;
            z-index: 100;
            height: 100vh;
        }
        .sidebar-header { padding: 20px; text-align: center; border-bottom: 1px solid var(--light-gray-color); }
        .sidebar-header .logo { font-size: 1.5rem; font-weight: 700; color: var(--primary-color); text-decoration: none; }
        .sidebar-menu { flex-grow: 1; padding: 20px 10px; overflow-y: auto; }
        .sidebar-menu h3 { font-size: 0.8rem; color: #999; padding: 0 15px 10px; text-transform: uppercase; font-weight: 700; }
        .sidebar-menu a { display: flex; align-items: center; padding: 12px 15px; color: #555; text-decoration: none; border-radius: 8px; margin-bottom: 8px; font-weight: 500; transition: background-color 0.2s, color 0.2s; }
        .sidebar-menu a:hover, .sidebar-menu a.active { background-image: var(--primary-gradient); color: var(--white-color); }
        .sidebar-menu a i { margin-right: 15px; width: 20px; text-align: center; }
        .sidebar-footer { padding: 20px; border-top: 1px solid var(--light-gray-color); flex-shrink: 0; }
        #userInfo { font-size: 0.9em; color: #666; margin-bottom: 15px; padding: 10px; background: var(--secondary-color); border-radius: 6px; text-align: center; }
        #logoutLink, #loginLink { display: block; width: 100%; padding: 12px; border: none; border-radius: 8px; cursor: pointer; text-align: center; text-decoration: none; font-weight: 500; transition: opacity 0.2s; }
        #logoutLink { background-color: var(--primary-color); color: var(--white-color); }
        #loginLink { background-color: #38a169; color: var(--white-color); }
        /* --- 추가된 반응형 스타일 --- */
    #sidebar-toggle { 
        display: none; 
        position: fixed; 
        top: 15px; 
        left: 15px; 
        z-index: 1001;
        background: var(--white-color); 
        border: 1px solid var(--border-color); 
        border-radius: 8px; 
        width: 40px; 
        height: 40px; 
        cursor: pointer; 
        font-size: 1.2rem;
        color: var(--primary-color);
    }

    @media (max-width: 768px) {
        body { 
            flex-direction: column; 
        }
        .main-content { 
            padding-top: 60px; 
        }
        #sidebar { 
            position: fixed; 
            transform: translateX(-100%); 
            height: 100%; 
            z-index: 1000;
        }
        #sidebar.open { 
            transform: translateX(0); 
        }
        #sidebar-toggle { 
            display: flex;
            align-items: center;
            justify-content: center;
        }
        #notification-prompt-banner {
            width: 90%;
            flex-direction: column;
            text-align: center;
            gap: 15px;
            bottom: 10px;
        }
    }