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

:root {
    --primary-color: #2ecc71;
    --primary-dark: #27ae60;
    --secondary-color: #3498db;
    --danger-color: #e74c3c;
    --text-dark: #333;
    --text-light: #666;
    --bg-light: #f5f5f5;
    --white: #ffffff;
    --shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 4px 20px rgba(0, 0, 0, 0.15);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background-color: var(--bg-light);
    color: var(--text-dark);
    line-height: 1.6;
    overflow-x: hidden;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Navigation */
.navbar {
    background-color: var(--white);
    box-shadow: var(--shadow);
    position: fixed;
    top: 0;
    width: 100%;
    z-index: 1000;
    transition: all 0.3s ease;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 70px;
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: 12px;
    font-weight: 700;
    font-size: 18px;
    color: var(--text-dark);
}

.logo-link {
    display: flex;
    align-items: center;
    gap: 12px;
    text-decoration: none;
    color: inherit;
}

.logo-img {
    height: 45px;
    width: auto;
    object-fit: contain;
    transition: opacity 0.3s ease;
}

.logo-img:hover {
    opacity: 0.8;
}

.fallback-logo {
    display: flex;
    gap: 4px;
}

.logo-books-small {
    display: flex;
    gap: 4px;
}

.logo-books-small .book {
    width: 32px;
    height: 32px;
    font-size: 18px;
}

.logo-text-nav {
    font-size: 16px;
    font-weight: 600;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 30px;
    align-items: center;
}

.nav-menu a {
    text-decoration: none;
    color: var(--text-dark);
    font-weight: 500;
    transition: color 0.3s ease;
}

.nav-menu a:hover {
    color: var(--primary-color);
}

.btn-login {
    background-color: var(--primary-color);
    color: var(--white) !important;
    padding: 8px 20px;
    border-radius: 5px;
    transition: background-color 0.3s ease;
}

.btn-login:hover {
    background-color: var(--primary-dark);
}

.btn-admin {
    background-color: var(--dark-color);
    color: var(--white) !important;
    padding: 8px 16px;
    border-radius: 5px;
    transition: background-color 0.3s ease;
    font-size: 14px;
}

.btn-admin:hover {
    background-color: #34495e;
}

.btn-admin i {
    margin-right: 5px;
}

.hamburger {
    display: none;
    flex-direction: column;
    cursor: pointer;
    gap: 5px;
}

.hamburger span {
    width: 25px;
    height: 3px;
    background-color: var(--text-dark);
    transition: all 0.3s ease;
    border-radius: 2px;
}

.hamburger.active span:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
}

.hamburger.active span:nth-child(2) {
    opacity: 0;
}

.hamburger.active span:nth-child(3) {
    transform: rotate(-45deg) translate(7px, -6px);
}

/* Hero Section */
.hero {
    margin-top: 70px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: var(--white);
    padding: 80px 20px;
    text-align: center;
}

.hero-container {
    max-width: 900px;
    margin: 0 auto;
}

.hero-logo {
    margin-bottom: 30px;
}

.logo-books {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 12px;
    margin-bottom: 16px;
}

.book {
    width: 60px;
    height: 60px;
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 32px;
    font-weight: bold;
    color: white;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
}

.book-r {
    background-color: var(--danger-color);
}

.book-d {
    background-color: var(--secondary-color);
}

.book-m {
    background-color: var(--primary-color);
}

.logo-text {
    font-size: 14px;
    font-weight: 600;
    color: rgba(255, 255, 255, 0.9);
    letter-spacing: 1px;
    text-transform: uppercase;
}

.hero-title {
    font-size: 42px;
    font-weight: 700;
    margin-bottom: 15px;
    line-height: 1.2;
}

.hero-subtitle {
    font-size: 28px;
    font-weight: 600;
    margin-bottom: 25px;
    opacity: 0.95;
}

.hero-description {
    font-size: 18px;
    margin-bottom: 15px;
    line-height: 1.8;
    opacity: 0.9;
}

.hero-note {
    font-size: 16px;
    margin-bottom: 40px;
    opacity: 0.85;
    font-style: italic;
}

.hero-features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
    margin-top: 50px;
}

.feature-item {
    background: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(10px);
    padding: 25px;
    border-radius: 12px;
    text-align: center;
}

.feature-item i {
    font-size: 36px;
    margin-bottom: 15px;
    display: block;
}

.feature-item span {
    display: block;
    font-size: 20px;
    font-weight: 600;
    margin-bottom: 8px;
}

.feature-item small {
    display: block;
    font-size: 14px;
    opacity: 0.9;
}

/* Section Styles */
.section-title {
    font-size: 36px;
    font-weight: 700;
    text-align: center;
    margin-bottom: 50px;
    color: var(--text-dark);
    position: relative;
}

.section-title::after {
    content: '';
    display: block;
    width: 80px;
    height: 4px;
    background: var(--primary-color);
    margin: 15px auto;
    border-radius: 2px;
}

.section-subtitle {
    text-align: center;
    color: var(--text-light);
    margin-bottom: 40px;
    font-size: 16px;
}

/* Why Choose Us */
.why-choose {
    padding: 80px 20px;
    background-color: var(--white);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
}

.feature-card {
    background: var(--white);
    padding: 30px;
    border-radius: 12px;
    text-align: center;
    box-shadow: var(--shadow);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.feature-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.feature-icon {
    width: 70px;
    height: 70px;
    background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 20px;
    color: var(--white);
    font-size: 28px;
}

.feature-card h3 {
    font-size: 20px;
    margin-bottom: 10px;
    color: var(--text-dark);
}

.feature-card p {
    color: var(--text-light);
    font-size: 14px;
}

/* Pricing */
.pricing {
    padding: 80px 20px;
    background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
    color: var(--white);
    text-align: center;
}

.pricing .section-title {
    color: var(--white);
}

.pricing .section-title::after {
    background: var(--white);
}

.pricing-subtitle {
    font-size: 18px;
    margin-bottom: 30px;
    opacity: 0.95;
}

.pricing-cta {
    margin-top: 30px;
}

/* Buttons */
.btn-primary {
    background-color: var(--white);
    color: var(--primary-color);
    padding: 14px 40px;
    font-size: 16px;
    font-weight: 600;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    text-decoration: none;
    display: inline-block;
    transition: all 0.3s ease;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 16px rgba(0, 0, 0, 0.3);
}

.btn-large {
    padding: 16px 50px;
    font-size: 18px;
}

/* Target Audience */
.target-audience {
    padding: 80px 20px;
    background-color: var(--bg-light);
}

.audience-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 30px;
}

.audience-card {
    background: var(--white);
    padding: 40px 20px;
    border-radius: 12px;
    text-align: center;
    box-shadow: var(--shadow);
    transition: transform 0.3s ease;
}

.audience-card:hover {
    transform: translateY(-5px);
}

.audience-icon {
    font-size: 64px;
    margin-bottom: 20px;
}

.audience-card h3 {
    font-size: 18px;
    color: var(--text-dark);
}

/* Process */
.process {
    padding: 80px 20px;
    background-color: var(--white);
}

.process-steps {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
}

.step {
    text-align: center;
    padding: 30px;
    position: relative;
}

.step-number {
    width: 60px;
    height: 60px;
    background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
    color: var(--white);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 28px;
    font-weight: bold;
    margin: 0 auto 20px;
}

.step h3 {
    font-size: 20px;
    margin-bottom: 15px;
    color: var(--text-dark);
}

.step p {
    color: var(--text-light);
    margin-bottom: 15px;
}

.step-link {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 600;
}

.step-link:hover {
    text-decoration: underline;
}

/* Features Section */
.features {
    padding: 80px 20px;
    background-color: var(--bg-light);
}

.features-list {
    display: grid;
    gap: 30px;
}

.feature-item-large {
    background: var(--white);
    padding: 40px;
    border-radius: 12px;
    box-shadow: var(--shadow);
    display: flex;
    gap: 30px;
    align-items: flex-start;
}

.feature-icon-large {
    width: 80px;
    height: 80px;
    background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--white);
    font-size: 36px;
    flex-shrink: 0;
}

.feature-item-large h3 {
    font-size: 24px;
    margin-bottom: 15px;
    color: var(--text-dark);
}

.feature-item-large p {
    color: var(--text-light);
    line-height: 1.8;
}

/* Register Section */
.register-section {
    padding: 80px 20px;
    background: linear-gradient(135deg, var(--secondary-color), #2980b9);
    color: var(--white);
    text-align: center;
}

.register-section .section-title {
    color: var(--white);
}

.register-section .section-title::after {
    background: var(--white);
}

.register-subtitle {
    font-size: 18px;
    margin-bottom: 30px;
    opacity: 0.95;
}

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

/* Guarantee */
.guarantee {
    padding: 60px 20px;
    background-color: var(--white);
}

.guarantee-box {
    max-width: 800px;
    margin: 0 auto;
    background: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
    padding: 40px;
    border-radius: 12px;
    text-align: center;
    color: var(--white);
    box-shadow: var(--shadow-lg);
}

.guarantee-box h2 {
    font-size: 28px;
    margin-bottom: 15px;
}

.guarantee-box p {
    font-size: 16px;
    line-height: 1.8;
}

/* FAQ */
.faq {
    padding: 80px 20px;
    background-color: var(--bg-light);
}

.faq-list {
    max-width: 900px;
    margin: 0 auto;
}

.faq-item {
    background: var(--white);
    margin-bottom: 15px;
    border-radius: 8px;
    overflow: hidden;
    box-shadow: var(--shadow);
}

.faq-question {
    padding: 20px;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: background-color 0.3s ease;
}

.faq-question:hover {
    background-color: #f8f9fa;
}

.faq-question h3 {
    font-size: 18px;
    color: var(--text-dark);
    flex: 1;
}

.faq-question i {
    color: var(--primary-color);
    transition: transform 0.3s ease;
}

.faq-item.active .faq-question i {
    transform: rotate(180deg);
}

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease;
}

.faq-item.active .faq-answer {
    max-height: 500px;
}

.faq-answer p {
    padding: 0 20px 20px;
    color: var(--text-light);
    line-height: 1.8;
}

/* Blog Section */
.blog-section {
    padding: 80px 20px;
    background-color: var(--white);
}

.blog-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

.blog-card {
    background: var(--white);
    padding: 30px;
    border-radius: 12px;
    box-shadow: var(--shadow);
    transition: transform 0.3s ease;
}

.blog-card:hover {
    transform: translateY(-5px);
}

.blog-card h3 {
    font-size: 20px;
    margin-bottom: 15px;
    color: var(--text-dark);
}

.blog-card p {
    color: var(--text-light);
    margin-bottom: 15px;
    line-height: 1.8;
}

.read-more {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 600;
}

.read-more:hover {
    text-decoration: underline;
}


/* Footer */
.footer {
    background-color: #2c3e50;
    color: var(--white);
    padding: 60px 20px 20px;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 40px;
    margin-bottom: 40px;
}

.footer-section h3 {
    font-size: 20px;
    margin-bottom: 20px;
}

.footer-section p {
    opacity: 0.8;
    line-height: 1.8;
}

.footer-section ul {
    list-style: none;
}

.footer-section ul li {
    margin-bottom: 10px;
}

.footer-section ul li a {
    color: var(--white);
    text-decoration: none;
    opacity: 0.8;
    transition: opacity 0.3s ease;
}

.footer-section ul li a:hover {
    opacity: 1;
}

.footer-bottom {
    text-align: center;
    padding-top: 20px;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    opacity: 0.8;
}

/* Responsive Design */
/* Tablet (768px - 1024px) */
@media (max-width: 1024px) {
    .container {
        padding: 0 30px;
    }

    .nav-container {
        padding: 0 30px;
    }

    .hero-title {
        font-size: 36px;
    }

    .hero-subtitle {
        font-size: 24px;
    }

    .hero-description {
        font-size: 16px;
    }

    .features-grid {
        grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
        gap: 25px;
    }

    .audience-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .process-steps {
        grid-template-columns: repeat(2, 1fr);
    }

    .blog-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .feature-item-large {
        padding: 30px;
    }
}

/* Mobile & Tablet Portrait (max-width: 768px) */
@media (max-width: 768px) {
    .hamburger {
        display: flex;
    }

    .nav-container {
        padding: 0 20px;
    }

    .nav-menu {
        position: fixed;
        left: -100%;
        top: 70px;
        flex-direction: column;
        background-color: var(--white);
        width: 100%;
        text-align: center;
        transition: 0.3s;
        box-shadow: var(--shadow-lg);
        padding: 20px 0;
        gap: 0;
        z-index: 999;
    }

    .nav-menu.active {
        left: 0;
    }

    .nav-menu li {
        width: 100%;
        padding: 15px 0;
    }

    .nav-menu a {
        display: block;
        padding: 10px 20px;
    }

    .btn-login,
    .btn-admin {
        margin: 10px 20px;
        display: inline-block;
        width: calc(100% - 40px);
        text-align: center;
    }

    .hero {
        padding: 60px 20px;
        margin-top: 70px;
    }

    .hero-title {
        font-size: 28px;
        line-height: 1.3;
    }

    .hero-subtitle {
        font-size: 20px;
    }

    .hero-description {
        font-size: 15px;
        line-height: 1.7;
    }

    .hero-note {
        font-size: 14px;
    }

    .hero-features {
        grid-template-columns: 1fr;
        gap: 20px;
        margin-top: 40px;
    }

    .feature-item {
        padding: 20px;
    }

    .section-title {
        font-size: 26px;
        margin-bottom: 40px;
    }

    .section-subtitle {
        font-size: 15px;
    }

    .why-choose,
    .target-audience,
    .process,
    .features,
    .faq,
    .blog-section,
    .register-section,
    .guarantee,
    .pricing {
        padding: 60px 20px;
    }

    .features-grid {
        grid-template-columns: 1fr;
        gap: 20px;
    }

    .feature-card {
        padding: 25px;
    }

    .audience-grid {
        grid-template-columns: 1fr;
        gap: 20px;
    }

    .audience-card {
        padding: 30px 20px;
    }

    .process-steps {
        grid-template-columns: 1fr;
        gap: 25px;
    }

    .step {
        padding: 25px 20px;
    }

    .feature-item-large {
        flex-direction: column;
        text-align: center;
        padding: 30px 20px;
        gap: 20px;
    }

    .feature-icon-large {
        width: 70px;
        height: 70px;
        font-size: 32px;
        margin: 0 auto;
    }

    .blog-grid {
        grid-template-columns: 1fr;
        gap: 20px;
    }

    .blog-card {
        padding: 25px;
    }

    .faq-list {
        max-width: 100%;
    }

    .faq-question h3 {
        font-size: 16px;
        padding-right: 10px;
    }

    .guarantee-box {
        padding: 30px 20px;
    }

    .guarantee-box h2 {
        font-size: 24px;
    }

    .guarantee-box p {
        font-size: 15px;
    }

    .pricing-subtitle {
        font-size: 16px;
    }

    .register-subtitle {
        font-size: 16px;
    }

    .btn-primary {
        padding: 12px 30px;
        font-size: 15px;
    }

    .btn-large {
        padding: 14px 40px;
        font-size: 16px;
    }

    .footer-content {
        grid-template-columns: 1fr;
        gap: 30px;
        text-align: center;
    }

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

/* Mobile Small (max-width: 480px) */
@media (max-width: 480px) {
    .nav-container {
        height: 60px;
    }

    .nav-logo {
        font-size: 16px;
    }

    .logo-text-nav {
        font-size: 14px;
    }

    .logo-img {
        height: 35px;
    }

    .logo-books-small .book {
        width: 28px;
        height: 28px;
        font-size: 16px;
    }

    .hero {
        padding: 40px 15px;
        margin-top: 60px;
    }

    .hero-title {
        font-size: 24px;
        margin-bottom: 12px;
    }

    .hero-subtitle {
        font-size: 18px;
        margin-bottom: 20px;
    }

    .hero-description {
        font-size: 14px;
        margin-bottom: 12px;
    }

    .hero-note {
        font-size: 13px;
        margin-bottom: 30px;
    }

    .logo-books {
        gap: 8px;
        margin-bottom: 12px;
    }

    .book {
        width: 45px;
        height: 45px;
        font-size: 26px;
    }

    .logo-text {
        font-size: 12px;
    }

    .hero-features {
        gap: 15px;
        margin-top: 30px;
    }

    .feature-item {
        padding: 18px;
    }

    .feature-item i {
        font-size: 30px;
        margin-bottom: 12px;
    }

    .feature-item span {
        font-size: 18px;
    }

    .feature-item small {
        font-size: 13px;
    }

    .section-title {
        font-size: 22px;
        margin-bottom: 30px;
    }

    .section-subtitle {
        font-size: 14px;
    }

    .why-choose,
    .target-audience,
    .process,
    .features,
    .faq,
    .blog-section,
    .register-section,
    .guarantee,
    .pricing {
        padding: 50px 15px;
    }

    .container {
        padding: 0 15px;
    }

    .feature-card {
        padding: 20px;
    }

    .feature-icon {
        width: 60px;
        height: 60px;
        font-size: 24px;
        margin-bottom: 15px;
    }

    .feature-card h3 {
        font-size: 18px;
    }

    .feature-card p {
        font-size: 13px;
    }

    .audience-icon {
        font-size: 50px;
        margin-bottom: 15px;
    }

    .audience-card h3 {
        font-size: 16px;
    }

    .step-number {
        width: 50px;
        height: 50px;
        font-size: 24px;
        margin-bottom: 15px;
    }

    .step h3 {
        font-size: 18px;
    }

    .step p {
        font-size: 14px;
    }

    .feature-item-large h3 {
        font-size: 20px;
    }

    .feature-item-large p {
        font-size: 14px;
    }

    .blog-card h3 {
        font-size: 18px;
    }

    .blog-card p {
        font-size: 14px;
    }

    .faq-question {
        padding: 15px;
    }

    .faq-question h3 {
        font-size: 15px;
    }

    .faq-answer p {
        padding: 0 15px 15px;
        font-size: 14px;
    }

    .guarantee-box {
        padding: 25px 15px;
    }

    .guarantee-box h2 {
        font-size: 20px;
    }

    .guarantee-box p {
        font-size: 14px;
    }

    .pricing-subtitle {
        font-size: 15px;
    }

    .register-subtitle {
        font-size: 15px;
    }

    .btn-primary {
        padding: 11px 25px;
        font-size: 14px;
    }

    .btn-large {
        padding: 13px 35px;
        font-size: 15px;
    }

    .footer {
        padding: 40px 15px 15px;
    }

    .footer-section h3 {
        font-size: 18px;
        margin-bottom: 15px;
    }

    .footer-section p,
    .footer-section ul li a {
        font-size: 14px;
    }
}

/* Mobile Extra Small (max-width: 360px) */
@media (max-width: 360px) {
    .hero-title {
        font-size: 20px;
    }

    .hero-subtitle {
        font-size: 16px;
    }

    .section-title {
        font-size: 20px;
    }

    .book {
        width: 40px;
        height: 40px;
        font-size: 24px;
    }

    .btn-primary {
        padding: 10px 20px;
        font-size: 13px;
    }
}