/* CSS Variables */
:root {
    /* Color Palette */
    --primary-color: #7b7c72;
    --secondary-color: #d7d3c5;
    --accent-color: #615c5f;
    --highlight-color: #75aeb8;
    
    /* Additional Colors */
    --white: #ffffff;
    --black: #000000;
    --gray-light: #f8f9fa;
    --gray-medium: #6c757d;
    --gray-dark: #343a40;
    
    /* Typography */
    --font-primary: 'Noto Sans SC', sans-serif;
    --font-secondary: 'Roboto', sans-serif;
    
    /* Spacing */
    --section-padding: 80px 0;
    --container-padding: 0 20px;
    --border-radius: 8px;
    --border-radius-lg: 12px;
    
    /* Shadows */
    --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 4px 8px rgba(0, 0, 0, 0.15);
    --shadow-lg: 0 8px 16px rgba(0, 0, 0, 0.2);
    
    /* Transitions */
    --transition-fast: 0.2s ease;
    --transition-normal: 0.3s ease;
    --transition-slow: 0.5s ease;
}

/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    font-family: var(--font-primary);
    line-height: 1.6;
    color: var(--accent-color);
    background-color: var(--white);
    overflow-x: hidden;
}

/* Container */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: var(--container-padding);
}

/* Section Headers */
.section-header {
    text-align: center;
    margin-bottom: 60px;
}

.section-title {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: 15px;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 15px;
}

.section-title i {
    color: var(--highlight-color);
}

.section-subtitle {
    font-size: 1.1rem;
    color: var(--gray-medium);
    max-width: 600px;
    margin: 0 auto;
}

/* Header */
.header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    z-index: 1000;
    box-shadow: var(--shadow-sm);
    transition: var(--transition-normal);
}

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

.nav-logo a {
    display: flex;
    align-items: center;
    gap: 10px;
    text-decoration: none;
    color: var(--primary-color);
    font-weight: 700;
    font-size: 1.5rem;
    transition: var(--transition-fast);
}

.nav-logo a:hover {
    color: var(--highlight-color);
}

.logo-img {
    width: 40px;
    height: 40px;
    border-radius: var(--border-radius);
}

.nav-menu {
    display: flex;
}

.nav-list {
    display: flex;
    list-style: none;
    gap: 30px;
}

.nav-link {
    display: flex;
    align-items: center;
    gap: 8px;
    text-decoration: none;
    color: var(--accent-color);
    font-weight: 500;
    padding: 10px 15px;
    border-radius: var(--border-radius);
    transition: var(--transition-fast);
    position: relative;
}

.nav-link:hover {
    color: var(--highlight-color);
    background-color: var(--secondary-color);
}

.nav-link i {
    font-size: 0.9rem;
}

/* Mobile Menu Toggle */
.nav-toggle {
    display: none;
    flex-direction: column;
    cursor: pointer;
    gap: 4px;
}

.bar {
    width: 25px;
    height: 3px;
    background-color: var(--accent-color);
    transition: var(--transition-fast);
    border-radius: 2px;
}

/* Hero Section */
.hero {
    background: linear-gradient(135deg, var(--secondary-color) 0%, var(--white) 100%);
    padding: 120px 0 80px;
    min-height: 100vh;
    display: flex;
    align-items: center;
}

.hero-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: var(--container-padding);
}

.hero-content {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 60px;
    align-items: center;
}

.hero-title {
    margin-bottom: 25px;
}

.title-main {
    display: block;
    font-size: 3.5rem;
    font-weight: 700;
    color: var(--primary-color);
    line-height: 1.2;
}

.title-sub {
    display: block;
    font-size: 1.8rem;
    font-weight: 400;
    color: var(--highlight-color);
    margin-top: 10px;
}

.hero-description {
    font-size: 1.2rem;
    color: var(--gray-medium);
    margin-bottom: 30px;
    line-height: 1.8;
}

.hero-features {
    display: flex;
    flex-wrap: wrap;
    gap: 15px;
    margin-bottom: 40px;
}

.feature-tag {
    display: flex;
    align-items: center;
    gap: 8px;
    background: var(--white);
    padding: 10px 15px;
    border-radius: var(--border-radius-lg);
    box-shadow: var(--shadow-sm);
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--accent-color);
    transition: var(--transition-fast);
}

.feature-tag:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.feature-tag i {
    color: var(--highlight-color);
}

.download-btn {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    background: linear-gradient(135deg, var(--highlight-color), var(--primary-color));
    color: var(--white);
    padding: 15px 30px;
    border-radius: var(--border-radius-lg);
    text-decoration: none;
    font-weight: 600;
    font-size: 1.1rem;
    box-shadow: var(--shadow-md);
    transition: var(--transition-normal);
}

.download-btn:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-lg);
}

.download-btn i {
    font-size: 1.2rem;
}

.hero-meta {
    background: var(--white);
    padding: 30px;
    border-radius: var(--border-radius-lg);
    box-shadow: var(--shadow-md);
}

.version-info {
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.version-item {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 0.95rem;
    color: var(--accent-color);
}

.version-item i {
    color: var(--highlight-color);
    width: 20px;
}

/* News Section */
.news {
    padding: var(--section-padding);
    background: var(--gray-light);
}

.news-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 30px;
}

.news-item {
    background: var(--white);
    border-radius: var(--border-radius-lg);
    box-shadow: var(--shadow-sm);
    overflow: hidden;
    transition: var(--transition-normal);
    display: flex;
}

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

.news-date {
    background: var(--highlight-color);
    color: var(--white);
    padding: 20px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    min-width: 80px;
}

.date-day {
    font-size: 1.8rem;
    font-weight: 700;
    line-height: 1;
}

.date-month {
    font-size: 0.9rem;
    font-weight: 500;
}

.news-content {
    padding: 25px;
    flex: 1;
}

.news-title {
    font-size: 1.3rem;
    font-weight: 600;
    color: var(--primary-color);
    margin-bottom: 15px;
    line-height: 1.4;
}

.news-excerpt {
    color: var(--gray-medium);
    margin-bottom: 20px;
    line-height: 1.6;
}

.news-link {
    color: var(--highlight-color);
    text-decoration: none;
    font-weight: 500;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    transition: var(--transition-fast);
}

.news-link:hover {
    gap: 12px;
}

/* Gallery Section */
.gallery {
    padding: var(--section-padding);
}

.gallery-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 25px;
}

.gallery-item {
    position: relative;
    border-radius: var(--border-radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow-md);
    transition: var(--transition-normal);
    cursor: pointer;
}

.gallery-item:hover {
    transform: scale(1.05);
    box-shadow: var(--shadow-lg);
}

.gallery-img {
    width: 100%;
    height: 250px;
    object-fit: cover;
    transition: var(--transition-normal);
}

.gallery-overlay {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.7);
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    transition: var(--transition-normal);
}

.gallery-item:hover .gallery-overlay {
    opacity: 1;
}

.gallery-overlay i {
    color: var(--white);
    font-size: 2rem;
}

/* Reviews Section */
.reviews {
    padding: var(--section-padding);
    background: var(--gray-light);
}

.reviews-stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 40px;
    margin-bottom: 50px;
}

.stat-item {
    text-align: center;
    background: var(--white);
    padding: 30px 20px;
    border-radius: var(--border-radius-lg);
    box-shadow: var(--shadow-sm);
}

.stat-number {
    font-size: 3rem;
    font-weight: 700;
    color: var(--highlight-color);
    margin-bottom: 10px;
}

.stat-label {
    font-size: 1rem;
    color: var(--gray-medium);
    margin-bottom: 15px;
}

.stat-stars {
    display: flex;
    justify-content: center;
    gap: 5px;
}

.stat-stars i {
    color: #ffc107;
    font-size: 1.2rem;
}

.reviews-tags {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 15px;
    margin-bottom: 50px;
}

.tag {
    background: var(--highlight-color);
    color: var(--white);
    padding: 8px 16px;
    border-radius: var(--border-radius-lg);
    font-size: 0.9rem;
    font-weight: 500;
}

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

.review-item {
    background: var(--white);
    padding: 30px;
    border-radius: var(--border-radius-lg);
    box-shadow: var(--shadow-sm);
    transition: var(--transition-normal);
}

.review-item:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-md);
}

.review-content {
    margin-bottom: 25px;
}

.review-content p {
    font-style: italic;
    color: var(--gray-medium);
    line-height: 1.6;
}

.review-author {
    display: flex;
    align-items: center;
    gap: 15px;
}

.author-avatar {
    width: 50px;
    height: 50px;
    background: var(--secondary-color);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--primary-color);
    font-size: 1.2rem;
}

.author-name {
    font-weight: 600;
    color: var(--primary-color);
    margin-bottom: 5px;
}

.review-rating {
    display: flex;
    gap: 3px;
}

.review-rating i {
    color: #ffc107;
    font-size: 0.9rem;
}

/* Updates Section */
.updates {
    padding: var(--section-padding);
}

.updates-timeline {
    position: relative;
    max-width: 800px;
    margin: 0 auto;
}

.updates-timeline::before {
    content: '';
    position: absolute;
    left: 30px;
    top: 0;
    bottom: 0;
    width: 2px;
    background: var(--secondary-color);
}

.timeline-item {
    position: relative;
    margin-bottom: 50px;
    padding-left: 80px;
}

.timeline-item::before {
    content: '';
    position: absolute;
    left: 20px;
    top: 20px;
    width: 20px;
    height: 20px;
    background: var(--highlight-color);
    border-radius: 50%;
    border: 4px solid var(--white);
    box-shadow: var(--shadow-sm);
}

.timeline-date {
    position: absolute;
    left: -80px;
    top: 15px;
    background: var(--primary-color);
    color: var(--white);
    padding: 8px 12px;
    border-radius: var(--border-radius);
    font-size: 0.9rem;
    font-weight: 500;
    white-space: nowrap;
}

.timeline-content {
    background: var(--white);
    padding: 30px;
    border-radius: var(--border-radius-lg);
    box-shadow: var(--shadow-sm);
    transition: var(--transition-normal);
}

.timeline-content:hover {
    box-shadow: var(--shadow-md);
}

.timeline-title {
    font-size: 1.4rem;
    font-weight: 600;
    color: var(--primary-color);
    margin-bottom: 15px;
}

.timeline-meta {
    display: flex;
    gap: 20px;
    margin-bottom: 20px;
}

.meta-item {
    display: flex;
    align-items: center;
    gap: 8px;
    color: var(--gray-medium);
    font-size: 0.9rem;
}

.meta-item i {
    color: var(--highlight-color);
}

.timeline-changes {
    list-style: none;
    margin-bottom: 25px;
}

.timeline-changes li {
    position: relative;
    padding-left: 20px;
    margin-bottom: 8px;
    color: var(--gray-medium);
    line-height: 1.5;
}

.timeline-changes li::before {
    content: '•';
    position: absolute;
    left: 0;
    color: var(--highlight-color);
    font-weight: bold;
}

.timeline-download {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    background: var(--highlight-color);
    color: var(--white);
    padding: 10px 20px;
    border-radius: var(--border-radius);
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition-fast);
}

.timeline-download:hover {
    background: var(--primary-color);
}

/* FAQ Section */
.faq {
    padding: var(--section-padding);
    background: var(--gray-light);
}

.faq-list {
    max-width: 800px;
    margin: 0 auto;
}

.faq-item {
    background: var(--white);
    border-radius: var(--border-radius-lg);
    margin-bottom: 20px;
    box-shadow: var(--shadow-sm);
    overflow: hidden;
    transition: var(--transition-normal);
}

.faq-item:hover {
    box-shadow: var(--shadow-md);
}

.faq-question {
    padding: 25px 30px;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: var(--transition-fast);
}

.faq-question:hover {
    background: var(--secondary-color);
}

.faq-question h3 {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--primary-color);
    margin: 0;
}

.faq-question i {
    color: var(--highlight-color);
    transition: var(--transition-fast);
}

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

.faq-answer {
    padding: 0 30px;
    max-height: 0;
    overflow: hidden;
    transition: var(--transition-normal);
}

.faq-item.active .faq-answer {
    padding: 0 30px 25px;
    max-height: 200px;
}

.faq-answer p {
    color: var(--gray-medium);
    line-height: 1.6;
    margin: 0;
}

/* Footer */
.footer {
    background: var(--accent-color);
    color: var(--white);
    padding: 60px 0 30px;
}

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

.footer-title {
    font-size: 1.2rem;
    font-weight: 600;
    margin-bottom: 20px;
    color: var(--secondary-color);
}

.footer-links {
    list-style: none;
}

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

.footer-links a {
    color: var(--white);
    text-decoration: none;
    transition: var(--transition-fast);
    opacity: 0.8;
}

.footer-links a:hover {
    opacity: 1;
    color: var(--secondary-color);
}

.footer-social {
    display: flex;
    gap: 15px;
}

.social-link {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    background: var(--primary-color);
    color: var(--white);
    border-radius: 50%;
    text-decoration: none;
    transition: var(--transition-fast);
}

.social-link:hover {
    background: var(--highlight-color);
    transform: translateY(-2px);
}

.footer-bottom {
    text-align: center;
    padding-top: 30px;
    border-top: 1px solid var(--primary-color);
    opacity: 0.8;
}

/* Back to Top Button */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 50px;
    height: 50px;
    background: var(--highlight-color);
    color: var(--white);
    border: none;
    border-radius: 50%;
    cursor: pointer;
    box-shadow: var(--shadow-md);
    transition: var(--transition-normal);
    opacity: 0;
    visibility: hidden;
    z-index: 1000;
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
}

.back-to-top:hover {
    background: var(--primary-color);
    transform: translateY(-3px);
}

/* Responsive Design */
@media (max-width: 768px) {
    :root {
        --section-padding: 60px 0;
    }
    
    .nav-menu {
        position: fixed;
        top: 70px;
        left: -100%;
        width: 100%;
        height: calc(100vh - 70px);
        background: var(--white);
        flex-direction: column;
        justify-content: flex-start;
        align-items: center;
        padding-top: 50px;
        transition: var(--transition-normal);
        box-shadow: var(--shadow-md);
    }
    
    .nav-menu.active {
        left: 0;
    }
    
    .nav-list {
        flex-direction: column;
        gap: 20px;
    }
    
    .nav-toggle {
        display: flex;
    }
    
    .nav-toggle.active .bar:nth-child(1) {
        transform: rotate(45deg) translate(5px, 5px);
    }
    
    .nav-toggle.active .bar:nth-child(2) {
        opacity: 0;
    }
    
    .nav-toggle.active .bar:nth-child(3) {
        transform: rotate(-45deg) translate(7px, -6px);
    }
    
    .section-title {
        font-size: 2rem;
        flex-direction: column;
        gap: 10px;
    }
    
    .hero {
        padding: 100px 0 60px;
        min-height: auto;
    }
    
    .hero-content {
        grid-template-columns: 1fr;
        gap: 40px;
        text-align: center;
    }
    
    .title-main {
        font-size: 2.5rem;
    }
    
    .title-sub {
        font-size: 1.4rem;
    }
    
    .hero-features {
        justify-content: center;
    }
    
    .news-grid {
        grid-template-columns: 1fr;
    }
    
    .news-item {
        flex-direction: column;
    }
    
    .news-date {
        flex-direction: row;
        justify-content: center;
        min-width: auto;
    }
    
    .gallery-grid {
        grid-template-columns: 1fr;
    }
    
    .reviews-stats {
        grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
        gap: 20px;
    }
    
    .stat-number {
        font-size: 2.5rem;
    }
    
    .reviews-carousel {
        grid-template-columns: 1fr;
    }
    
    .timeline-item {
        padding-left: 60px;
    }
    
    .timeline-date {
        position: static;
        margin-bottom: 15px;
        display: inline-block;
    }
    
    .updates-timeline::before {
        left: 20px;
    }
    
    .timeline-item::before {
        left: 10px;
    }
    
    .footer-content {
        grid-template-columns: 1fr;
        gap: 30px;
        text-align: center;
    }
    
    .back-to-top {
        bottom: 20px;
        right: 20px;
        width: 45px;
        height: 45px;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 15px;
    }
    
    .nav-container {
        padding: 0 15px;
    }
    
    .title-main {
        font-size: 2rem;
    }
    
    .title-sub {
        font-size: 1.2rem;
    }
    
    .hero-description {
        font-size: 1rem;
    }
    
    .feature-tag {
        font-size: 0.8rem;
        padding: 8px 12px;
    }
    
    .download-btn {
        padding: 12px 24px;
        font-size: 1rem;
    }
    
    .hero-meta {
        padding: 20px;
    }
    
    .news-content,
    .timeline-content,
    .review-item {
        padding: 20px;
    }
    
    .faq-question {
        padding: 20px;
    }
    
    .faq-item.active .faq-answer {
        padding: 0 20px 20px;
    }
}