/* ===== CSS Variables ===== */
:root {
    --primary-color: #c8102e;
    --secondary-color: #ffd700;
    --text-color: #333;
    --light-bg: #f5f5f5;
}

/* ===== Reset ===== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Arial, sans-serif;
}

body {
    color: var(--text-color);
    line-height: 1.6;
    padding-top: 80px;
    background-color: var(--light-bg);
}
        /* === Reset & Font === */
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            font-family: 'Segoe UI', Arial, sans-serif;
        }
        
        body {
            color: #333;
            line-height: 1.6;
            padding-top: 80px; /* Offset for fixed header */
            background-color: #f5f5f5;
        }
        
        /* === Header === */
        header {
            background-color: #c8102e;
            color: white;
            padding: 10px 0;
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            z-index: 1000;
            box-shadow: 0 2px 8px rgba(0,0,0,0.2);
        }
        
        .header-container {
            display: flex;
            justify-content: space-between;
            align-items: center;
            max-width: 1200px;
            margin: 0 auto;
            padding: 0 20px;
        }
        
        .logo {
            display: flex;
            align-items: center;
            gap: 15px;
        }
        
        .logo img {
            height: 60px;
        }
        
        .logo-text h1 {
            font-size: 22px;
            font-weight: bold;
            line-height: 1.2;
            margin-bottom: 5px;
        }
        
        .logo-text p {
            font-size: 14px;
            font-weight: bold;
            color: #ffd700;
            text-shadow: 0 1px 2px rgba(0,0,0,0.3);
        }
        
        /* === Navigation === */
        nav ul {
            display: flex;
            list-style: none;
            align-items: center;
        }
        
        nav ul li {
            margin-left: 20px;
            position: relative;
        }
        
        nav ul li a {
            color: white;
            text-decoration: none;
            font-weight: 600;
            font-size: 16px;
            transition: all 0.3s;
            padding: 8px 0;
            display: block;
            position: relative;
        }
        
        nav ul li a:hover {
            color: #ffd700;
        }
        
        nav ul li a:after {
            content: '';
            position: absolute;
            width: 0;
            height: 2px;
            background: #ffd700;
            bottom: 0;
            left: 0;
            transition: width 0.3s;
        }
        
        nav ul li a:hover:after {
            width: 100%;
        }
        
        .register-btn {
            background: white;
            color: #c8102e;
            padding: 8px 20px;
            border-radius: 30px;
            font-weight: bold;
            margin-left: 15px;
            transition: all 0.3s;
        }
        
        .register-btn:hover {
            background: #f0f0f0;
            transform: translateY(-2px);
            box-shadow: 0 4px 8px rgba(0,0,0,0.1);
        }
        
        /* === Mobile Menu Toggle === */
        .menu-toggle {
            display: none;
            cursor: pointer;
            font-size: 24px;
            color: white;
        }
        
        /* === Multi-level Dropdown Menu === */
        nav ul li {
            position: relative;
        }

        nav ul ul {
            position: absolute;
            top: 100%;
            left: 0;
            background: white;
            min-width: 200px;
            box-shadow: 0 5px 15px rgba(0,0,0,0.1);
            opacity: 0;
            visibility: hidden;
            transition: all 0.3s;
            transform: translateY(10px);
            z-index: 100;
        }

        nav ul ul ul {
            left: 100%;
            top: 0;
        }

        nav ul li:hover > ul {
            opacity: 1;
            visibility: visible;
            transform: translateY(0);
        }

        nav ul ul li {
            margin: 0;
            border-bottom: 1px solid #eee;
        }

        nav ul ul li:last-child {
            border-bottom: none;
        }

        nav ul ul a {
            color: #333 !important;
            padding: 10px 15px !important;
            white-space: nowrap;
        }

        nav ul ul a:hover {
            background: #f0f0f0 !important;
            color: #c8102e !important;
            padding-left: 15px !important;
        }

        nav ul ul .fa-chevron-right {
            float: right;
            font-size: 12px;
            margin-top: 5px;
        }
        
        /* === Main container === */
        .container {
            max-width: 1200px;
            margin: 30px auto;
            padding: 0 20px;
            display: flex;
            gap: 30px;
        }
        
        /* === Left sidebar === */
        .sidebar {
            width: 25%;
        }
        
        .sidebar-section {
            background: white;
            border-radius: 5px;
            box-shadow: 0 2px 5px rgba(0,0,0,0.1);
            margin-bottom: 20px;
            overflow: hidden;
        }
        
        .sidebar-title {
            background-color: #c8102e;
            color: white;
            padding: 12px 15px;
            font-size: 18px;
            font-weight: bold;
        }
        
        .article-list {
            list-style: none;
        }
        
        .article-list li {
            border-bottom: 1px solid #eee;
        }
        
        .article-list li:last-child {
            border-bottom: none;
        }
        
        .article-list a {
            display: block;
            padding: 12px 15px;
            color: #333;
            text-decoration: none;
            transition: all 0.3s;
        }
        
        .article-list a:hover {
            background-color: #f0f0f0;
            color: #c8102e;
            padding-left: 20px;
        }
        
        /* === Main content === */
        .main-content {
            width: 75%;
            background: white;
            border-radius: 5px;
            box-shadow: 0 2px 5px rgba(0,0,0,0.1);
            padding: 30px;
        }
        
        .article-title {
            color: #c8102e;
            font-size: 28px;
            margin-bottom: 20px;
            padding-bottom: 10px;
            border-bottom: 2px solid #ffd700;
            text-align: center;
        }
        
        .article-subtitle {
            color: #c8102e;
            font-size: 22px;
            margin: 30px 0 20px;
            padding-left: 15px;
            border-left: 4px solid #ffd700;
        }
        
        .article-content {
            margin-bottom: 30px;
        }
        
        .article-content p {
            margin-bottom: 15px;
            text-align: justify;
        }
        
        .article-image {
            max-width: 100%;
            height: auto;
            margin: 25px 0;
            border-radius: 8px;
            border: 1px solid #ddd;
            transition: transform 0.3s, box-shadow 0.3s;
        }
        
        .article-image:hover {
            transform: translateY(-3px);
            box-shadow: 0 5px 15px rgba(0,0,0,0.1);
        }
        
        .image-caption {
            text-align: center;
            font-style: italic;
            color: #666;
            margin-top: -10px;
            margin-bottom: 25px;
        }
        
        /* === Bảng thông tin === */
        .info-table {
            width: 100%;
            border-collapse: collapse;
            margin: 25px 0;
            box-shadow: 0 2px 5px rgba(0,0,0,0.05);
        }
        
        .info-table th, .info-table td {
            border: 1px solid #ddd;
            padding: 12px;
            text-align: left;
            transition: background-color 0.3s;
        }
        
        .info-table th {
            background-color: #c8102e;
            color: white;
        }
        
        .info-table tr:nth-child(even) {
            background-color: #f9f9f9;
        }
        
        .info-table tr:hover {
            background-color: #f0f0f0;
        }
        
        /* === Danh sách giáo viên === */
        .teacher-list {
            display: flex;
            flex-wrap: wrap;
            gap: 20px;
            margin: 25px 0;
        }
        
        .teacher-card {
            width: calc(50% - 10px);
            background: #f9f9f9;
            border-radius: 5px;
            padding: 20px;
            box-shadow: 0 2px 5px rgba(0,0,0,0.1);
            transition: all 0.3s;
        }
        
        .teacher-card:hover {
            transform: translateY(-5px);
            box-shadow: 0 5px 15px rgba(0,0,0,0.1);
            background: white;
        }
        
        .teacher-name {
            color: #c8102e;
            font-weight: bold;
            font-size: 18px;
            margin-bottom: 8px;
        }
        
        /* === Features Section === */
        .features {
            background: #f9f9f9;
            padding: 40px 30px;
            margin: 40px -30px;
            border-radius: 5px;
        }
        
        .features-grid {
            display: grid;
            grid-template-columns: repeat(4, 1fr);
            gap: 30px;
            text-align: center;
        }
        
        .feature-item {
            background: white;
            padding: 30px 20px;
            border-radius: 8px;
            box-shadow: 0 5px 15px rgba(0,0,0,0.05);
            transition: all 0.3s;
        }
        
        .feature-item:hover {
            transform: translateY(-5px);
            box-shadow: 0 10px 25px rgba(0,0,0,0.1);
        }
        
        .feature-item i {
            font-size: 40px;
            color: #c8102e;
            margin-bottom: 20px;
        }
        
        .feature-item h3 {
            margin-bottom: 15px;
            color: #333;
            font-size: 18px;
        }
        
        .feature-item p {
            color: #666;
            font-size: 15px;
        }
        
        /* === Footer === */
        footer {
            background: #1a1a1a;
            color: white;
            padding: 60px 0 20px;
        }
        
        .footer-container {
            display: grid;
            grid-template-columns: repeat(3, 1fr);
            gap: 40px;
            max-width: 1200px;
            margin: 0 auto;
            padding: 0 20px;
        }
        
        .footer-col h3 {
            font-size: 20px;
            margin-bottom: 20px;
            position: relative;
            padding-bottom: 10px;
            color: #ffd700;
        }
        
        .footer-col h3:after {
            content: '';
            position: absolute;
            width: 50px;
            height: 2px;
            background: #c8102e;
            bottom: 0;
            left: 0;
        }
        
        .footer-col p {
            color: #bbb;
            font-size: 15px;
            line-height: 1.6;
        }
        
        .footer-col ul {
            list-style: none;
        }
        
        .footer-col ul li {
            margin-bottom: 10px;
        }
        
        .footer-col ul li a {
            color: #ddd;
            text-decoration: none;
            transition: all 0.3s;
            display: inline-block;
        }
        
        .footer-col ul li a:hover {
            color: #ffd700;
            transform: translateX(5px);
        }
        
        .contact-info p {
            margin-bottom: 15px;
            display: flex;
            align-items: center;
            color: #ddd;
        }
        
        .contact-info i {
            margin-right: 10px;
            color: #c8102e;
            width: 20px;
            text-align: center;
        }
        
        .social-links a {
            display: inline-block;
            color: white;
            margin-right: 15px;
            font-size: 20px;
            transition: all 0.3s;
        }
        
        .social-links a:hover {
            color: #ffd700;
            transform: translateY(-3px);
        }
        
        .copyright {
            text-align: center;
            padding-top: 30px;
            margin-top: 30px;
            border-top: 1px solid rgba(255,255,255,0.1);
            color: #bbb;
            font-size: 14px;
        }
        
        /* === Chatbox === */
        .chat-icon {
            position: fixed;
            bottom: 20px;
            left: 20px;
            width: 60px;
            height: 60px;
            background-color: #10c875;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            cursor: pointer;
            box-shadow: 0 4px 12px rgba(0,0,0,0.2);
            z-index: 1000;
            transition: transform 0.3s;
        }
        
        .chat-icon:hover {
            transform: scale(1.1);
        }
        
        .chat-icon i {
            color: white;
            font-size: 24px;
        }
        
        .chat-box {
            position: fixed;
            bottom: 90px;
            left: 20px;
            width: 350px;
            height: 450px;
            background: white;
            border-radius: 10px;
            box-shadow: 0 5px 15px rgba(0,0,0,0.2);
            z-index: 1001;
            opacity: 0;
            transform: translateY(20px);
            transition: all 0.3s ease;
            display: none;
            flex-direction: column;
        }
        
        .chat-box.show {
            opacity: 1;
            transform: translateY(0);
            display: flex;
        }
        
        .chat-header {
            background: #6fc810;
            color: white;
            padding: 15px;
            border-top-left-radius: 10px;
            border-top-right-radius: 10px;
            display: flex;
            justify-content: space-between;
            align-items: center;
        }
        
        .chat-header h3 {
            margin: 0;
            font-size: 16px;
        }
        
        .close-chat {
            background: none;
            border: none;
            color: white;
            font-size: 20px;
            cursor: pointer;
            transition: transform 0.3s;
        }
        
        .close-chat:hover {
            transform: rotate(90deg);
        }
        
        /* === Popup Form === */
        #popupForm {
            display: none;
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background-color: rgba(0,0,0,0.5);
            z-index: 1000;
        }
        
        .popup-content {
            background: white;
            width: 90%;
            max-width: 600px;
            margin: 60px auto;
            padding: 30px;
            border-radius: 10px;
            position: relative;
            overflow-y: auto;
            max-height: 80vh;
            box-shadow: 0 5px 25px rgba(0,0,0,0.2);
        }
        
        .close-popup {
            position: absolute;
            top: 10px;
            right: 15px;
            background: none;
            border: none;
            font-size: 24px;
            cursor: pointer;
            transition: color 0.3s;
        }
        
        .close-popup:hover {
            color: #c8102e;
        }
        
        /* === Responsive === */
        @media (max-width: 992px) {
            .features-grid {
                grid-template-columns: repeat(2, 1fr);
            }
            
            .footer-container {
                grid-template-columns: repeat(2, 1fr);
            }
        }
        
        @media (max-width: 768px) {
            .container {
                flex-direction: column;
            }
            
            .sidebar, .main-content {
                width: 100%;
            }
            
            .teacher-card {
                width: 100%;
            }
            
            .features-grid {
                grid-template-columns: 1fr;
            }
            
            .footer-container {
                grid-template-columns: 1fr;
            }
            
            /* Mobile menu styles */
            .menu-toggle {
                display: block;
            }
            
            nav {
                position: fixed;
                top: 80px;
                left: -100%;
                width: 80%;
                height: calc(100vh - 80px);
                background-color: #c8102e;
                transition: all 0.3s ease;
                z-index: 999;
                overflow-y: auto;
            }
            
            nav.active {
                left: 0;
            }
            
            nav ul {
                flex-direction: column;
                padding: 20px 0;
            }
            
            nav ul li {
                margin: 0;
                width: 100%;
                text-align: left;
                border-bottom: 1px solid rgba(255,255,255,0.1);
            }
            
            nav ul li a {
                padding: 15px 20px;
            }
            
            nav ul ul {
                position: static;
                display: none;
                background-color: rgba(0,0,0,0.1);
                box-shadow: none;
                opacity: 1;
                visibility: visible;
                transform: none;
                width: 100%;
            }
            
            nav ul ul.active {
                display: block;
            }
            
            nav ul ul li {
                border-bottom: none;
            }
            
            nav ul ul a {
                padding-left: 30px !important;
            }
            
            nav ul ul ul a {
                padding-left: 45px !important;
            }
            
            .register-btn {
                margin: 15px 20px;
                width: calc(100% - 40px);
                text-align: center;
            }
        }
        /* Thêm vào cuối file styles2.css */
        .article-image {
            width: 100%;
            max-width: 100%;
            height: auto;
            display: block;
            margin: 25px 0;
            border-radius: 8px;
            border: 1px solid #ddd;
            transition: transform 0.3s, box-shadow 0.3s;
        }
        /* === Legal Document Styles === */
.legal-document {
    font-family: 'Times New Roman', Times, serif;
    line-height: 1.8;
}

.document-title {
    color: var(--primary-color);
    font-size: 20px;
    margin-bottom: 20px;
    text-align: center;
    border-bottom: 1px solid #ddd;
    padding-bottom: 10px;
}

.document-header {
    margin: 25px 0;
}

.divider {
    height: 1px;
    background: linear-gradient(to right, transparent, var(--primary-color), transparent);
    margin: 15px 0;
}

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

.text-right {
    text-align: right;
}

.info-section {
    margin: 30px 0;
}

.info-section h4 {
    color: var(--primary-color);
    margin-bottom: 15px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.info-section h4 i {
    color: var(--primary-color);
}

.styled-list {
    list-style-type: none;
    padding-left: 20px;
}

.styled-list li {
    position: relative;
    padding-left: 25px;
    margin-bottom: 10px;
}

.styled-list li:before {
    content: "•";
    color: var(--primary-color);
    font-size: 20px;
    position: absolute;
    left: 0;
    top: -2px;
}

.document-footer {
    margin-top: 50px;
    padding-top: 20px;
    border-top: 1px solid #ddd;
}
/* === Thời khóa biểu === */
.timetable-section {
    margin-bottom: 30px;
}

.timetable-section h5 {
    color: var(--primary-color);
    margin: 20px 0 15px;
    padding-bottom: 5px;
    border-bottom: 1px dashed #ddd;
}

/* === Danh sách giáo viên chi tiết === */
.teacher-details {
    margin-top: 20px;
}

.teacher-category {
    margin-bottom: 30px;
}

.teacher-category h5 {
    color: var(--primary-color);
    font-size: 18px;
    margin-bottom: 15px;
}

.teacher-card.detailed {
    display: flex;
    align-items: center;
    padding: 15px;
    margin-bottom: 15px;
    background: #f9f9f9;
    border-radius: 8px;
}

.teacher-avatar {
    width: 80px;
    height: 80px;
    border-radius: 50%;
    overflow: hidden;
    margin-right: 20px;
    border: 2px solid var(--primary-color);
}

.teacher-avatar img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.teacher-info {
    flex: 1;
}

.teacher-qualification {
    color: #666;
    font-style: italic;
    margin: 5px 0;
}

.teacher-experience {
    background: var(--primary-color);
    color: white;
    display: inline-block;
    padding: 3px 10px;
    border-radius: 15px;
    font-size: 13px;
    margin: 5px 0;
}

.teacher-subjects {
    color: #555;
    font-weight: 500;
}

.teacher-notes {
    margin-top: 30px;
    padding: 15px;
    background: #f0f0f0;
    border-radius: 8px;
}