/* Reset và cơ bản */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Roboto Fallback', sans-serif;
    line-height: 1.6;
    color: #333;
    
}

.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 15px;
}

img {
    max-width: 100%;
    height: auto;
}

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

ul {
    list-style: none;
}

/* Màu sắc chính của Viettel */
:root {
    --primary-color: #ed0817;
    --secondary-color: #f5f5f5;
    --accent-color: #ff9800;
    --dark-color: #333;
    --light-color: #fff;
    --border-color: #ddd;
    --shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

/* Header */
header {
    background-color: var(--light-color);
    box-shadow: var(--shadow);
    position: sticky;
    top: 0;
    z-index: 100;
    padding: 15px 0;
}
 

header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo img {
    height: 40px;
}

nav ul {
    display: flex;
}

nav ul li {
    margin-left: 20px;
}

nav ul li a {
    font-weight: 500;
    transition: color 0.3s;
}

nav ul li a:hover {
    color: var(--primary-color);
}

/*CSS Responsive (thêm phần dành cho mobile)*/
/* ----- HEADER STYLE ----- */
header {
    width: 100%;
    background: #fff;
    padding: 10px 0;
}

header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

nav ul {
    list-style: none;
    display: flex;
    gap: 25px;
}

nav ul li a {
    text-decoration: none;
    color: #333;
    font-weight: 500;
}

/* ----- HAMBURGER MENU (ẩn khi desktop) ----- */
.menu-toggle {
    display: none;
    flex-direction: column;
    cursor: pointer;
    gap: 5px;
}

.menu-toggle span {
    width: 28px;
    height: 3px;
    background: #333;
    border-radius: 2px;
}

/* ----- MOBILE RESPONSIVE ----- */
@media (max-width: 768px) {

    /* Hiện nút hamburger */
    .menu-toggle {
        display: flex;
    }

    nav {
        position: absolute;
        top: 70px;
        right: 0;
        width: 100%;
        background: white;
        border-top: 1px solid #eee;
        display: none;
    }

    nav ul {
        flex-direction: column;
        padding: 15px 0;
        gap: 15px;
        text-align: center;
    }

    nav.show {
        display: block;
    }
}

/* ----- HERO IMAGE RESPONSIVE ----- */
.hero-image {
    width: 100%;
    height: auto;
}

.hero-image img {
    width: 100%;
    height: auto;
    object-fit: cover;
    display: block;
}
/*CSS Responsive (thêm phần dành cho mobile)*/

/* Hero Section */
.hero {
    background-color: var(--secondary-color);
    padding: 60px 0;
}

.hero-content {
    display: flex;
    align-items: center;
    gap: 40px;
}

.hero-text {
    flex: 1;
}

.hero-text h1 {
    font-size: 2.5rem;
    margin-bottom: 10px;
    color: var(--dark-color);
}

.hero-text h2 {
    font-size: 2rem;
    color: var(--primary-color);
    margin-bottom: 20px;
}

.hero-image {
    flex: 1;
    border-radius: 10px;
    border-bottom-left-radius: 10px;
    border-bottom-right-radius: 10px;
    height: 100%;
    overflow: hidden;
}

/*Responsive cho Hero section*/
@media (max-width: 768px) {
    .hero-image img {
        height: 375px;
        
    }
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 12px 24px;
    border-radius: 5px;
    font-weight: 600;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s ease;
    border: none;
}

.btn-primary {
    background-color: var(--primary-color);
    color: var(--light-color);
}

.btn-primary:hover {
    background-color: #c00;
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(227, 6, 19, 0.3);
}

.btn-outline {
    background-color: transparent;
    border: 2px solid var(--primary-color);
    color: var(--primary-color);
}

.btn-outline:hover {
    background-color: var(--primary-color);
    color: var(--light-color);
    transform: translateY(-2px);
}

/* Section Styles */
section {
    padding: 60px 0;
}

.section-title {
    font-size: 2rem;
    text-align: center;
    margin-bottom: 40px;
    color: var(--dark-color);
}

.section-desc {
    text-align: center;
    max-width: 700px;
    margin: 0 auto 40px;
    color: #666;
}

/* Package Cards */
.package-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
    margin-top: 30px;
}

.package-card {
    background-color: var(--light-color);
    border-radius: 10px;
    overflow: hidden;
    box-shadow: var(--shadow);
    transition: transform 0.3s, box-shadow 0.3s;
}

.package-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.1);
}

.package-header {
    background-color: #f8f8f8;
    padding: 20px;
    text-align: center;
    position: relative;
}

.package-header h3 {
    font-size: 1.5rem;
    color: var(--primary-color);
}

.badge {
    position: absolute;
    top: 0;
    right: 0;
    background-color: var(--accent-color);
    color: var(--light-color);
    padding: 5px 10px;
    font-size: 0.8rem;
    border-radius: 0 0 0 5px;
}

.package-body {
    padding: 20px;
}

.package-body ul li {
    margin-bottom: 10px;
    display: flex;
    align-items: center;
}

.package-body ul li i {
    color: var(--primary-color);
    margin-right: 10px;
}

.package-footer {
    padding: 20px;
    text-align: center;
}

/* Featured Package */
.package-card.featured {
    border: 2px solid var(--primary-color);
    transform: scale(1.05);
}

.package-card.featured .package-header {
    background-color: var(--primary-color);
    color: var(--light-color);
}

.package-card.featured .package-header h3 {
    color: var(--light-color);
}

.package-card.featured .badge {
    background-color: var(--light-color);
    color: var(--primary-color);
}

/* Newsletter Section */
.newsletter {
    background-color: #f8f8f8;
}

.newsletter-content {
    display: flex;
    align-items: center;
    gap: 40px;
}

.newsletter-image {
    flex: 1;
    border-radius: 50px;
}

.newsletter-form {
    flex: 1;
    background-color: var(--light-color);
    padding: 30px;
    border-radius: 10px;
    box-shadow: var(--shadow);
}

.newsletter-form h3 {
    font-size: 1.5rem;
    margin-bottom: 20px;
    text-align: center;
}

.newsletter-form input {
    width: 100%;
    padding: 12px;
    margin-bottom: 15px;
    border: 1px solid var(--border-color);
    border-radius: 5px;
}

/* Features Section */
.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

.feature-item {
    text-align: center;
    padding: 20px;
}

.feature-item img {
    width: 100%;
    border-radius: 10px;
    margin-bottom: 20px;
}

.feature-item h3 {
    font-size: 1.2rem;
    margin-bottom: 10px;
    color: var(--dark-color);
}

/* Footer */
footer {
    text-align: center;
}

.footer-main {
    background-color: #ffffff;
    padding: 30px 0;
}

.footer-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
}

.footer-logo {
    margin-bottom: 20px;
}

.footer-logo img {
    height: 50px;
}

.footer-copyright {
    background-color: var(--primary-color); /* Màu đỏ Viettel */
    color: #ffffff;
    padding: 15px 0;
    font-size: 0.9rem;
}

/* Responsive Footer */
@media (max-width: 768px) {
    .footer-logo img {
        height: 40px;
    }
    
    .footer-main {
        padding: 20px 0;
    }
    
    .footer-copyright {
        padding: 10px 0;
        font-size: 0.8rem;
    }
}

:root {
    --primary-color: #ed2517; /* Màu đỏ Viettel */
    --secondary-color: #F5F5F5;
    --text-color: #333333;
    --light-gray: #E8E8E8;
    --white: #FFFFFF;
    --shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    --border-radius: 8px;
}

/* Section Styling */
.packages-section {
    padding: 20px 0;
    background-color: var(--white);
}

.section-title {
    font-size: 32px;
    font-weight: 700;
    color: var(--text-color);
    text-align: center;
    margin-bottom: 16px;
}

.section-desc {
    font-size: 18px;
    color: #666;
    text-align: center;
    max-width: 800px;
    margin: 0 auto 40px;
    line-height: 1.6;
}

/* Package Cards Container */
.packages-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
    margin-bottom: 40px;
}

/* Package Card Styling */
.package-card {
    background-color: var(--white);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    overflow: hidden;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    display: flex;
    flex-direction: column;
    height: 100%;
}

.package-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.15);
}

/* Package Header */
.package-header {
    background-color: var(--primary-color);
    color: var(--white);
    padding: 20px;
    position: relative;
    text-align: center;
}

.package-name {
    background-color: var(--secondary-color);
    border-radius: 5px;
    font-size: 22px;
    font-weight: 700;
    margin: 0 0 10px;
}

.package-price {
    font-size: 24px;
    font-weight: 700;
    margin-bottom: 5px;
}

.package-tag {
    position: absolute;
    top: 10px;
    right: 10px;
    background-color: #FFD700; /* Gold color */
    color: #333;
    font-size: 12px;
    font-weight: 700;
    padding: 4px 8px;
    border-radius: 4px;
}

/* Package Body */
.package-body {
    padding: 20px;
    flex-grow: 1;
}

.package-features {
    list-style-type: none;
    padding: 0;
    margin: 0;
}

.package-features li {
    padding: 10px 0;
    border-bottom: 1px solid var(--light-gray);
    font-size: 16px;
    line-height: 1.5;
}

.package-features li:last-child {
    border-bottom: none;
}

.package-features li strong {
    font-size: 20px;
    color: var(--primary-color);
    display: block;
    margin-bottom: 5px;
}

/* Package Footer */
.package-footer {
    padding: 20px;
    display: flex;
    flex-direction: column;
    gap: 10px;
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 12px 24px;
    font-size: 16px;
    font-weight: 700;
    text-align: center;
    text-decoration: none;
    border-radius: 4px;
    cursor: pointer;
    transition: all 0.3s ease;
}

.btn-primary {
    background-color: var(--primary-color);
    color: var(--white);
    border: none;
}

.btn-primary:hover {
    background-color: #B82318; /* Darker red */
}

.btn-outline {
    background-color: transparent;
    color: var(--primary-color);
    border: 1px solid var(--primary-color);
}

.btn-outline:hover {
    background-color: rgba(213, 43, 30, 0.1);
}

.btn-outline-secondary {
    background-color: transparent;
    color: #666;
    border: 1px solid #666;
    padding: 10px 20px;
}

.btn-outline-secondary:hover {
    background-color: #f0f0f0;
}

/* View More Button */
.view-more {
    text-align: center;
    margin-top: 20px;
}

/* Responsive Design */
@media (max-width: 992px) {
    .packages-container {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 768px) {
    .packages-container {
        grid-template-columns: 1fr;
    }
    
    .section-title {
        font-size: 28px;
    }
    
    .section-desc {
        font-size: 16px;
    }
}

/* Hiệu ứng nổi bật cho gói được chọn nhiều */
.package-card.featured {
    transform: scale(1.05);
    border: 2px solid var(--primary-color);
}

/* Hiệu ứng cho nút "Xem thêm" */
.view-more .btn {
    position: relative;
    overflow: hidden;
}

.view-more .btn::after {
    content: "";
    position: absolute;
    top: 50%;
    right: 15px;
    width: 8px;
    height: 8px;
    border-right: 2px solid #666;
    border-bottom: 2px solid #666;
    transform: translateY(-50%) rotate(45deg);
    transition: transform 0.3s ease;
}

.view-more .btn:hover::after {
    transform: translateY(-50%) rotate(45deg) translateX(3px);
}

/* Hiệu ứng loading khi click vào nút đăng ký */
.btn-primary.loading {
    position: relative;
    color: transparent;
}

.btn-primary.loading::after {
    content: "";
    position: absolute;
    width: 20px;
    height: 20px;
    top: 50%;
    left: 50%;
    margin-top: -10px;
    margin-left: -10px;
    border: 3px solid rgba(255, 255, 255, 0.3);
    border-radius: 50%;
    border-top-color: var(--white);
    animation: spin 1s ease-in-out infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}


:root {
    --primary-color: #D52B1E;
    --secondary-color: #F5F5F5;
    --text-color: #333333;
    --light-gray: #E8E8E8;
    --white: #FFFFFF;
    --shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    --border-radius: 8px;
    --messenger-blue: #0084FF;
}

/* Existing CSS remains the same... */

/* Button styling with icons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 12px 24px;
    font-size: 16px;
    font-weight: 700;
    text-align: center;
    text-decoration: none;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

.btn-primary {
    background-color: var(--primary-color);
    color: var(--white);
}

.btn-primary:hover {
    background-color: #B82318;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(213, 43, 30, 0.3);
}

.btn-outline {
    background-color: transparent;
    color: var(--messenger-blue);
    border: 1px solid var(--messenger-blue);
}

.btn-outline:hover {
    background-color: var(--messenger-blue);
    color: var(--white);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 132, 255, 0.3);
}

/* Icon styling */
.phone-icon, .messenger-icon {
    font-size: 18px;
    transition: transform 0.3s ease;
}

.btn:hover .phone-icon {
    transform: rotate(15deg) scale(1.1);
}

.btn:hover .messenger-icon {
    transform: scale(1.2);
}

/* Loading animation */
.btn.loading {
    position: relative;
    color: transparent;
    pointer-events: none;
}

.btn.loading::after {
    content: "";
    position: absolute;
    width: 20px;
    height: 20px;
    top: 50%;
    left: 50%;
    margin-top: -10px;
    margin-left: -10px;
    border: 3px solid rgba(255, 255, 255, 0.3);
    border-radius: 50%;
    border-top-color: var(--white);
    animation: spin 1s ease-in-out infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

/* Pulse animation for call button */
.btn-register.calling {
    animation: pulse 1.5s infinite;
}

@keyframes pulse {
    0% {
        box-shadow: 0 0 0 0 rgba(213, 43, 30, 0.7);
    }
    70% {
        box-shadow: 0 0 0 10px rgba(213, 43, 30, 0);
    }
    100% {
        box-shadow: 0 0 0 0 rgba(213, 43, 30, 0);
    }
}

/* Success animation */
.btn.success {
    background-color: #28a745;
    color: var(--white);
}

.btn.success::before {
    content: "✓";
    position: absolute;
    font-size: 20px;
    animation: checkmark 0.5s ease-in-out;
}

@keyframes checkmark {
    0% {
        transform: scale(0);
        opacity: 0;
    }
    50% {
        transform: scale(1.2);
        opacity: 1;
    }
    100% {
        transform: scale(1);
        opacity: 1;
    }
}

/* Modal Styling */
.phone-modal, .contact-modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 1000;
    animation: fadeIn 0.3s ease;
}

.modal-content {
    background-color: var(--white);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    max-width: 500px;
    width: 90%;
    max-height: 80vh;
    overflow-y: auto;
}

.modal-header {
    padding: 20px;
    border-bottom: 1px solid var(--light-gray);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.modal-header h3 {
    margin: 0;
    color: var(--text-color);
}

.close-modal {
    background: none;
    border: none;
    font-size: 24px;
    cursor: pointer;
    color: #999;
}

.close-modal:hover {
    color: var(--text-color);
}

.modal-body {
    padding: 20px;
}

.phone-display {
    display: flex;
    align-items: center;
    gap: 10px;
    margin: 15px 0;
    padding: 15px;
    background-color: var(--secondary-color);
    border-radius: var(--border-radius);
}

.phone-link {
    font-size: 24px;
    font-weight: 700;
    color: var(--primary-color);
    text-decoration: none;
}

.copy-phone, .copy-message {
    background-color: var(--primary-color);
    color: var(--white);
    border: none;
    padding: 8px 12px;
    border-radius: 4px;
    cursor: pointer;
    font-size: 14px;
}

.copy-phone:hover, .copy-message:hover {
    background-color: #B82318;
}

.contact-options {
    display: flex;
    flex-direction: column;
    gap: 10px;
    margin: 15px 0;
}

.contact-option {
    display: block;
    padding: 12px;
    background-color: var(--secondary-color);
    border-radius: var(--border-radius);
    text-decoration: none;
    color: var(--text-color);
    transition: background-color 0.3s ease;
}

.contact-option:hover {
    background-color: var(--light-gray);
}

.message-preview {
    margin-top: 20px;
}

.message-preview textarea {
    width: 100%;
    height: 100px;
    padding: 10px;
    border: 1px solid var(--light-gray);
    border-radius: var(--border-radius);
    resize: vertical;
    font-family: inherit;
}

.note {
    font-size: 14px;
    color: #666;
    font-style: italic;
    margin-top: 10px;
}

/* Notification Styling */
.notification {
    position: fixed;
    top: 20px;
    right: 20px;
    background-color: var(--white);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    z-index: 1001;
    animation: slideIn 0.3s ease;
}

.notification-content {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 15px;
}

.notification-icon {
    font-size: 20px;
}

.notification-message {
    flex-grow: 1;
    color: var(--text-color);
}

.notification-close {
    background: none;
    border: none;
    font-size: 18px;
    cursor: pointer;
    color: #999;
}

.notification-close:hover {
    color: var(--text-color);
}

.notification-info {
    border-left: 4px solid #17a2b8;
}

.notification-success {
    border-left: 4px solid #28a745;
}

.notification-warning {
    border-left: 4px solid #ffc107;
}

/* Animations */
@keyframes fadeIn {
    from {
        opacity: 0;
    }
    to {
        opacity: 1;
    }
}

@keyframes slideIn {
    from {
        transform: translateX(100%);
        opacity: 0;
    }
    to {
        transform: translateX(0);
        opacity: 1;
    }
}

/* Responsive */
@media (max-width: 768px) {
    .modal-content {
        width: 95%;
        margin: 10px;
    }
    
    .phone-display {
        flex-direction: column;
        text-align: center;
    }
    
    .notification {
        top: 10px;
        right: 10px;
        left: 10px;
        width: auto;
    }
}

/* Messenger Modal Styling */
.messenger-modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 1000;
    animation: fadeIn 0.3s ease;
}

.messenger-modal .modal-content {
    background-color: var(--white);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    max-width: 600px;
    width: 90%;
    max-height: 85vh;
    overflow-y: auto;
}

.contact-methods {
    display: grid;
    gap: 20px;
    margin: 20px 0;
}

.contact-method {
    padding: 20px;
    border: 1px solid var(--light-gray);
    border-radius: var(--border-radius);
    background-color: var(--secondary-color);
}

.contact-method h4 {
    margin: 0 0 10px 0;
    color: var(--text-color);
    font-size: 16px;
}

.contact-method p {
    margin: 0 0 15px 0;
    color: #666;
    font-size: 14px;
}

.contact-btn {
    background-color: var(--primary-color);
    color: var(--white);
    border: none;
    padding: 12px 20px;
    border-radius: 4px;
    cursor: pointer;
    font-size: 14px;
    font-weight: 600;
    transition: all 0.3s ease;
    width: 100%;
}

.contact-btn:hover {
    background-color: #B82318;
    transform: translateY(-1px);
}

.facebook-profile {
    background-color: #1877F2;
}

.facebook-profile:hover {
    background-color: #166FE5;
}

.messenger-web {
    background-color: #0084FF;
}

.messenger-web:hover {
    background-color: #0073E6;
}

.phone-call {
    background-color: #28a745;
}

.phone-call:hover {
    background-color: #218838;
}

.copy-section {
    margin-top: 15px;
}

.message-text {
    width: 100%;
    height: 80px;
    padding: 10px;
    border: 1px solid var(--light-gray);
    border-radius: var(--border-radius);
    resize: vertical;
    font-family: inherit;
    font-size: 14px;
    margin-bottom: 10px;
}

.copy-buttons {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
    gap: 8px;
}

.copy-btn {
    background-color: #6c757d;
    color: var(--white);
    border: none;
    padding: 8px 12px;
    border-radius: 4px;
    cursor: pointer;
    font-size: 12px;
    transition: all 0.3s ease;
}

.copy-btn:hover {
    background-color: #5a6268;
}

.contact-info {
    margin-top: 20px;
    padding: 15px;
    background-color: #f8f9fa;
    border-radius: var(--border-radius);
}

.contact-info h4 {
    margin: 0 0 10px 0;
    color: var(--text-color);
}

.contact-info ul {
    margin: 0;
    padding-left: 20px;
}

.contact-info li {
    margin-bottom: 5px;
    font-size: 14px;
}

/* Responsive cho Messenger Modal */
@media (max-width: 768px) {
    .messenger-modal .modal-content {
        width: 95%;
        margin: 10px;
    }
    
    .contact-methods {
        grid-template-columns: 1fr;
    }
    
    .copy-buttons {
        grid-template-columns: 1fr;
    }
}

/* Scroll to Top Button */
.scroll-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 50px;
    height: 50px;
    background: linear-gradient(135deg, var(--primary-color), #B82318);
    color: var(--white);
    border: none;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 4px 20px rgba(220, 38, 27, 0.3);
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    z-index: 999;
    opacity: 0;
    visibility: hidden;
    transform: translateY(20px) scale(0.8);
}

.scroll-to-top.visible {
    opacity: 1;
    visibility: visible;
    transform: translateY(0) scale(1);
}

.scroll-to-top:hover {
    background: linear-gradient(135deg, #B82318, var(--primary-color));
    transform: translateY(-3px) scale(1.1);
    box-shadow: 0 8px 25px rgba(220, 38, 27, 0.4);
}

.scroll-to-top:active {
    transform: translateY(-1px) scale(1.05);
}

.scroll-arrow {
    width: 24px;
    height: 24px;
    transition: transform 0.3s ease;
}

.scroll-to-top:hover .scroll-arrow {
    transform: translateY(-2px);
    animation: bounce 1s infinite;
}

/* Animation cho mũi tên */
@keyframes bounce {
    0%, 20%, 50%, 80%, 100% {
        transform: translateY(-2px);
    }
    40% {
        transform: translateY(-6px);
    }
    60% {
        transform: translateY(-4px);
    }
}

/* Hiệu ứng pulse khi xuất hiện */
.scroll-to-top.visible {
    animation: pulseIn 0.6s ease-out;
}

@keyframes pulseIn {
    0% {
        opacity: 0;
        transform: translateY(20px) scale(0.3);
    }
    50% {
        transform: translateY(-5px) scale(1.1);
    }
    100% {
        opacity: 1;
        transform: translateY(0) scale(1);
    }
}

/* Responsive cho mobile */
@media (max-width: 768px) {
    .scroll-to-top {
        bottom: 20px;
        right: 20px;
        width: 45px;
        height: 45px;
    }
    
    .scroll-arrow {
        width: 20px;
        height: 20px;
    }
}

/* Dark mode support */
@media (prefers-color-scheme: dark) {
    .scroll-to-top {
        background: linear-gradient(135deg, #ffffff, #555);
        box-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
    }
    
    .scroll-to-top:hover {
        background: linear-gradient(135deg, #555, #777);
        box-shadow: 0 8px 25px rgba(255, 255, 255, 0.4);
    }
}

.footer-simple {
    background: #ffffff;
    color: white;
    padding: 0px 0;
}

.footer-simple .footer-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 40px;
}

.footer-left {
    display: flex;
    align-items: center;
    gap: 15px;
}

.footer-logo {
    width: 180px;
    height: 80px;
    /*filter: brightness(0) invert(1);*/
}

.logo-info h3 {
    margin: 0;
    font-size: 24px;
    color: white;
}

.logo-info p {
    margin: 0;
    font-size: 14px;
    color: #ccc;
    font-style: italic;
}

.footer-right h4 {
    margin: 0 0 15px 0;
    font-size: 18px;
    color: rgb(22, 22, 22);
}

.contact-list {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.contact-row {
    display: flex;
    gap: 30px;
    font-size: 14px;
    color: #1a1919;
}

.contact-row a {
    color: rgb(31, 31, 31);
    text-decoration: none;
}

.contact-row a:hover {
    color: var(--primary-color);
}

.footer-bottom {
    text-align: center;
    margin-top: 20px;
    padding-top: 20px;
    border-top: 1px solid #333;
}

@media (max-width: 768px) {
    .footer-simple .footer-container {
        flex-direction: column;
        text-align: center;
        gap: 20px;
    }
    
    .contact-row {
        flex-direction: column;
        gap: 5px;
    }
}