/* --- Styles for Auth Page --- */
.auth-container {
    max-width: 550px;
    width: 100%;
    margin: 30px auto;
    background-color: rgba(10, 25, 47, 0.85);
    backdrop-filter: blur(12px);
    border: 1px solid rgba(0, 255, 255, 0.4);
    border-radius: 15px;
    box-shadow: 0 8px 32px rgba(0, 255, 255, 0.2);
    overflow: hidden;
    color: #e0e0e0;
}

.auth-tabs {
    display: flex;
    background-color: rgba(0, 0, 0, 0.3);
}

.tab-link {
    flex: 1;
    padding: 18px;
    text-align: center;
    cursor: pointer;
    background: transparent;
    border: none;
    color: #a0a0a0;
    font-size: 1.1rem;
    font-weight: bold;
    transition: all 0.3s ease-in-out;
    border-bottom: 4px solid transparent;
}

.tab-link.active {
    color: #f0b90b; /* Primary AI color */
    border-bottom-color: #f0b90b;
}

.tab-content {
    display: none;
    padding: 25px 35px;
}

.tab-content.active {
    display: block;
    animation: fadeIn 0.6s ease;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(15px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.auth-container form .form-group {
    margin-bottom: 20px;
}

.auth-container form label {
    display: block;
    margin-bottom: 8px;
    font-size: 0.9rem;
    color: #c0c0c0;
}

.auth-container form input {
    width: 100%;
    padding: 12px 15px;
    background-color: rgba(0, 0, 0, 0.5);
    border: 1px solid #444;
    border-radius: 8px;
    color: #ffffff;
    font-size: 1rem;
    box-sizing: border-box;
    transition: border-color 0.3s, box-shadow 0.3s;
}

.auth-container form input:focus {
    outline: none;
    border-color: #f0b90b;
    box-shadow: 0 0 10px rgba(240, 185, 11, 0.5);
}

.btn-auth {
    width: 100%;
    padding: 15px;
    margin-top: 10px;
    font-size: 1.1rem;
    font-weight: bold;
    background-color: #f0b90b;
    color: #111;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    transition: background-color 0.3s, transform 0.2s;
}

.btn-auth:hover {
    background-color: #ffd666;
    transform: translateY(-2px);
}

/* --- Message and Payment Area --- */
#auth-message {
    padding: 0 35px 20px 35px;
    text-align: center;
    font-weight: bold;
    font-size: 1rem;
}
#auth-message.success { color: #16c784; }
#auth-message.error { color: #ea3943; }

#payment-area {
    padding: 0 35px 30px 35px;
    text-align: center;
    animation: fadeIn 0.6s ease;
}

.payment-section h4 {
    color: #f0b90b;
    font-size: 1.3rem;
    margin-top: 0;
    margin-bottom: 15px;
}

.payment-section .package-selector {
    margin-bottom: 20px;
}

.payment-section select {
    width: 100%;
    padding: 10px;
    border-radius: 8px;
    background-color: rgba(0,0,0,0.5);
    color: white;
    border: 1px solid #444;
    font-size: 1rem;
}

.payment-section .qr-code {
    max-width: 250px;
    width: 80%;
    height: auto;
    margin-top: 10px;
    border: 3px solid white;
    border-radius: 8px;
}

.payment-section .transfer-syntax {
    background-color: rgba(0,0,0,0.6);
    padding: 15px;
    border-radius: 8px;
    margin-top: 20px;
    position: relative;
    border: 1px dashed #555;
}

.payment-section .transfer-syntax p {
    margin: 5px 0;
    font-family: 'Courier New', Courier, monospace;
    word-wrap: break-word;
}

.payment-section #copy-syntax-btn {
    position: absolute;
    top: 10px;
    right: 10px;
    padding: 5px 10px;
    cursor: pointer;
    background: #555;
    border: none;
    color: white;
    border-radius: 5px;
    font-size: 0.8rem;
}

        /* Biến màu để tương thích với trang của bạn */
        :root {
            --primary-color: #007bff;
            --text-color: #ffffff;
            --border-glow-color: #00ffff;
        }

        /* Reset cơ bản */
        body {
            margin: 0;
            font-family: sans-serif;
            background-color: #0a0a14; /* Nền tối để dễ nhìn */
        }
        
        /* --- CODE HEADER HOÀN CHỈNH --- */
        #main-header {
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: 50px;
            background-color: var(--primary-color);
            z-index: 1000;
            display: flex;
            align-items: center;
            justify-content: center;
            box-shadow: 0 2px 10px rgba(0, 0, 0, 0.5);
            border-bottom: 2px solid var(--border-glow-color);
        }

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

        .logo-container {
            display: flex;
            align-items: center;
            text-decoration: none;
            color: var(--text-color);
            /* Đảm bảo logo không bị đẩy xuống */
            flex-shrink: 0; 
        }

        .logo-container img {
            height: 40px;
            margin-right: 15px;
        }

        .header-title {
            font-weight: bold;
            font-size: 1em;
            letter-spacing: 1px;
            white-space: nowrap;
        }

        /* --- Menu cho máy tính --- */
        .main-navigation {
            display: flex; /* Mặc định hiển thị trên desktop */
        }

        .main-navigation ul {
            list-style: none;
            margin: 0;
            padding: 0;
            display: flex;
            align-items: center;
        }

        .main-navigation li {
            margin-left: 25px;
        }

        .main-navigation a {
            color: var(--text-color);
            text-decoration: none;
            font-weight: bold;
        }

        /* --- Nút Menu 3 sọc cho di động --- */
        .menu-toggle {
            display: none; /* Mặc định ẩn trên desktop */
            width: 30px;
            height: 25px;
            background: transparent;
            border: none;
            cursor: pointer;
            z-index: 1100;
        }

        .menu-toggle .bar {
            display: block;
            width: 100%;
            height: 3px;
            background-color: white;
            border-radius: 10px;
            margin: 5px 0;
            transition: all 0.3s ease-in-out;
        }

        /* --- QUY TẮC RESPONSIVE QUAN TRỌNG NHẤT --- */
        @media (max-width: 768px) {
            .header-title {
                /* Ẩn tiêu đề chữ để có không gian cho logo và nút menu */
                display: none; 
            }
            
            .main-navigation {
                /* Ẩn menu ngang và chuẩn bị cho menu xổ dọc */
                display: none;
                position: absolute;
                top: 50px;
                left: 0;
                width: 100%;
                background-color: rgba(0, 100, 200, 0.98);
            }
            
            /* LỚP .is-open SẼ ĐƯỢC JAVASCRIPT THÊM VÀO ĐỂ HIỂN THỊ MENU */
            .main-navigation.is-open {
                display: block;
            }

            .main-navigation ul {
                flex-direction: column; /* Chuyển menu thành cột dọc */
            }

            .main-navigation li {
                margin: 0;
                width: 100%;
                text-align: center;
                border-bottom: 1px solid rgba(255, 255, 255, 0.2);
            }

            .main-navigation a {
                display: block;
                padding: 15px;
            }

            .menu-toggle {
                /* HIỂN THỊ NÚT 3 SỌC */
                display: block !important; /* Dùng !important để đảm bảo không bị quy tắc nào khác ghi đè */
            }
        }
    

/* --- RESPONSIVE STYLES (MEDIA QUERIES) --- */
@media (max-width: 992px) { /* Breakpoint for tablets and smaller */
    .header-title {
        display: none; /* Hide title on smaller screens for more space */
    }
}

@media (max-width: 768px) { /* Breakpoint for mobile phones */
    .header-title {
        /* Re-display the title on mobile as requested */
        display: block; 
        font-size: 0.7em; /* Make title smaller to fit */
    }
    
    .main-navigation {
        display: none; /* Hide the desktop nav */
        position: absolute;
        top: 50px;
        left: 0;
        width: 100%;
        background-color: rgba(0, 100, 200, 0.98);
        backdrop-filter: blur(5px);
    }
    
    .main-navigation.is-open {
        display: block; /* Show nav when button is clicked */
    }

    .main-navigation ul {
        flex-direction: column;
        width: 100%;
    }

    .main-navigation li {
        margin: 0;
        text-align: center;
        border-bottom: 1px solid rgba(255, 255, 255, 0.2);
    }
    
    .main-navigation li:last-child {
        border-bottom: none;
    }

    .main-navigation a {
        display: block;
        padding: 20px;
    }

    .menu-toggle {
        display: flex; /* Show the hamburger button */
    }
}