/* ===== Reset & Base ===== */
*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --bg-primary: #ffffff;
    --bg-card: #ffffff;
    --bg-card-hover: #fafafa;
    --bg-section-alt: #f7f7f7;
    --black: #000000;
    --coral: #ff424d;
    --coral-light: #fff0ef;
    --text-primary: #000000;
    --text-secondary: #6f6f6f;
    --text-muted: #999999;
    --border-color: #e8e8e8;
    --border-color-hover: #d0d0d0;
    --shadow-card: 0 1px 3px rgba(0, 0, 0, 0.06);
    --shadow-card-hover: 0 8px 30px rgba(0, 0, 0, 0.08);
    --radius: 12px;
    --radius-lg: 20px;
    --transition: 0.3s ease;
}

html {
    scroll-behavior: smooth;
    scroll-padding-top: 80px;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.7;
    -webkit-font-smoothing: antialiased;
    overflow-x: hidden;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

a {
    text-decoration: none;
    color: inherit;
    transition: color var(--transition);
}

img {
    max-width: 100%;
    display: block;
}

/* ===== Buttons ===== */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 12px 28px;
    border-radius: 50px;
    font-size: 15px;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition);
    border: none;
    white-space: nowrap;
}

.btn-primary {
    background: var(--black);
    color: #fff;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.12);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(0, 0, 0, 0.2);
    background: #222;
}

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

.btn-outline:hover {
    border-color: var(--black);
    background: rgba(0, 0, 0, 0.03);
}

.btn-lg {
    padding: 16px 36px;
    font-size: 17px;
}

/* ===== Navbar ===== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    padding: 16px 0;
    transition: all var(--transition);
    background: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid transparent;
}

.navbar.scrolled {
    padding: 10px 0;
    background: rgba(255, 255, 255, 0.95);
    border-bottom-color: var(--border-color);
}

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

.nav-logo {
    font-size: 22px;
    font-weight: 700;
    color: var(--text-primary);
    display: flex;
    align-items: center;
    gap: 8px;
}

.nav-logo i {
    color: var(--black);
    font-size: 24px;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 4px;
}

.nav-link {
    padding: 8px 16px;
    border-radius: 8px;
    font-size: 14px;
    color: var(--text-secondary);
    transition: all var(--transition);
}

.nav-link:hover,
.nav-link.active {
    color: var(--text-primary);
    background: rgba(0, 0, 0, 0.04);
}

.nav-toggle {
    display: none;
    background: none;
    border: none;
    color: var(--text-primary);
    font-size: 22px;
    cursor: pointer;
    padding: 8px;
}

.nav-cta {
    padding: 10px 24px;
    font-size: 14px;
}

/* ===== Hero ===== */
.hero {
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 120px 0 64px;
    overflow: hidden;
    background: var(--bg-primary);
}

.hero-bg-effects {
    position: absolute;
    inset: 0;
    pointer-events: none;
}

.hero-glow {
    position: absolute;
    border-radius: 50%;
    filter: blur(120px);
    opacity: 0.06;
}

.hero-glow-1 {
    width: 600px;
    height: 600px;
    background: var(--coral);
    top: -100px;
    right: -100px;
}

.hero-glow-2 {
    width: 500px;
    height: 500px;
    background: #6366f1;
    bottom: -100px;
    left: -100px;
}

.hero-content {
    position: relative;
    text-align: center;
    max-width: 800px;
    margin: 0 auto;
}

.hero-title {
    font-size: 44px;
    font-weight: 800;
    line-height: 1.2;
    margin-bottom: 16px;
    letter-spacing: -0.03em;
    color: var(--black);
}

.hero-title span {
    background: linear-gradient(135deg, var(--coral), #e8350f);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: 16px;
    color: var(--text-secondary);
    max-width: 600px;
    margin: 0 auto 28px;
    line-height: 1.75;
}

.hero-buttons {
    display: flex;
    gap: 14px;
    justify-content: center;
    flex-wrap: wrap;
    margin-bottom: 40px;
}

.hero-stats {
    display: flex;
    justify-content: center;
    gap: 60px;
}

.hero-stat {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.hero-stat-number {
    font-size: 32px;
    font-weight: 700;
    color: var(--black);
}

.hero-stat-label {
    font-size: 14px;
    color: var(--text-muted);
    margin-top: 4px;
}

/* ===== Section Common ===== */
.section {
    padding: 100px 0;
}

.section-alt {
    background: var(--bg-section-alt);
}

.section-header {
    text-align: center;
    margin-bottom: 60px;
}

.section-title {
    font-size: 38px;
    font-weight: 700;
    margin-bottom: 12px;
    letter-spacing: -0.02em;
    color: var(--black);
}

.section-subtitle {
    font-size: 17px;
    color: var(--text-secondary);
}

/* ===== Grid ===== */
.grid {
    display: grid;
    gap: 24px;
}

.grid-4 {
    grid-template-columns: repeat(4, 1fr);
}

.grid-3 {
    grid-template-columns: repeat(3, 1fr);
}

/* ===== Cards ===== */
.card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    padding: 32px;
    transition: all var(--transition);
}

.card:hover {
    border-color: var(--border-color-hover);
    box-shadow: var(--shadow-card-hover);
    transform: translateY(-4px);
}

.card-title {
    font-size: 20px;
    font-weight: 600;
    margin-bottom: 12px;
    color: var(--black);
}

.card-desc {
    font-size: 15px;
    color: var(--text-secondary);
    line-height: 1.7;
}

/* ===== Feature Cards ===== */
.card-icon {
    width: 56px;
    height: 56px;
    border-radius: 14px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 24px;
    margin-bottom: 20px;
}

.icon-coral {
    background: #fff0ef;
    color: var(--coral);
}

.icon-cyan {
    background: #ecfeff;
    color: #0891b2;
}

.icon-green {
    background: #ecfdf5;
    color: #059669;
}

.icon-purple {
    background: #f5f3ff;
    color: #7c3aed;
}

/* ===== Highlight Cards ===== */
.highlight-card {
    position: relative;
    padding-top: 40px;
}

.highlight-number {
    font-size: 48px;
    font-weight: 800;
    color: rgba(0, 0, 0, 0.04);
    position: absolute;
    top: 16px;
    right: 24px;
    line-height: 1;
}

/* ===== Audience Cards ===== */
.audience-card {
    text-align: center;
    padding: 40px 32px;
}

.audience-icon {
    width: 80px;
    height: 80px;
    border-radius: 50%;
    background: var(--bg-section-alt);
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 24px;
    font-size: 32px;
    color: var(--black);
}

.card-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-top: 16px;
}

.audience-card .card-tags {
    justify-content: center;
}

.tag {
    padding: 4px 14px;
    border-radius: 50px;
    font-size: 13px;
    background: var(--bg-section-alt);
    color: var(--text-secondary);
    border: 1px solid var(--border-color);
}

/* ===== FAQ ===== */
.faq-list {
    max-width: 800px;
    margin: 0 auto;
}

.faq-item {
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    margin-bottom: 12px;
    overflow: hidden;
    background: var(--bg-card);
    transition: border-color var(--transition);
}

.faq-item:hover {
    border-color: var(--border-color-hover);
}

.faq-item.active {
    border-color: var(--black);
}

.faq-question {
    width: 100%;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 20px 24px;
    background: none;
    border: none;
    color: var(--text-primary);
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    text-align: left;
    transition: color var(--transition);
}

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

.faq-icon {
    font-size: 14px;
    color: var(--text-muted);
    transition: transform var(--transition), color var(--transition);
    flex-shrink: 0;
    margin-left: 16px;
}

.faq-item.active .faq-icon {
    transform: rotate(180deg);
    color: var(--black);
}

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.4s ease, padding 0.3s ease;
}

.faq-answer p {
    padding: 0 24px 20px;
    font-size: 15px;
    color: var(--text-secondary);
    line-height: 1.8;
}

.faq-item.active .faq-answer {
    max-height: 600px;
}

/* ===== Reviews ===== */
.reviews-stats {
    display: flex;
    justify-content: center;
    gap: 60px;
    margin-bottom: 32px;
}

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

.review-stat-icon {
    font-size: 28px;
    color: var(--coral);
    margin-bottom: 8px;
}

.review-stat-number {
    font-size: 36px;
    font-weight: 700;
    color: var(--black);
}

.review-stat-label {
    font-size: 14px;
    color: var(--text-muted);
    margin-top: 4px;
}

.tag-cloud {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 10px;
    margin-bottom: 48px;
}

.tag-cloud-item {
    padding: 6px 18px;
    font-size: 14px;
}

.reviews-grid {
    grid-template-columns: repeat(3, 1fr);
}

.reviews-grid .review-card:nth-child(4),
.reviews-grid .review-card:nth-child(5) {
    grid-column: span 1;
}

.review-card {
    padding: 28px;
}

.review-header {
    display: flex;
    align-items: center;
    gap: 14px;
    margin-bottom: 16px;
}

.review-avatar {
    width: 48px;
    height: 48px;
    border-radius: 50%;
    background: var(--black);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 18px;
    font-weight: 700;
    color: #fff;
    flex-shrink: 0;
}

.review-name {
    font-size: 16px;
    font-weight: 600;
    color: var(--black);
}

.review-stars {
    display: flex;
    gap: 2px;
    margin-top: 4px;
}

.review-stars i {
    font-size: 13px;
    color: #fbbf24;
}

.review-text {
    font-size: 15px;
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: 12px;
    font-style: italic;
}

/* ===== News ===== */
.news-card {
    padding: 28px;
    display: flex;
    flex-direction: column;
}

.news-badge {
    display: inline-block;
    padding: 4px 12px;
    border-radius: 50px;
    font-size: 12px;
    font-weight: 600;
    margin-bottom: 16px;
    width: fit-content;
}

.badge-update {
    background: #ecfeff;
    color: #0891b2;
}

.badge-announce {
    background: #fff0ef;
    color: var(--coral);
}

.badge-dev {
    background: #ecfdf5;
    color: #059669;
}

.news-title {
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 8px;
    line-height: 1.5;
    color: var(--black);
}

.news-date {
    font-size: 13px;
    color: var(--text-muted);
    margin-bottom: 12px;
    display: flex;
    align-items: center;
    gap: 6px;
}

.news-card .card-desc {
    flex: 1;
    margin-bottom: 16px;
}

.news-link {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    font-size: 14px;
    font-weight: 600;
    color: var(--black);
    transition: gap var(--transition);
}

.news-link:hover {
    gap: 10px;
}

/* ===== CTA Section ===== */
.cta-section {
    position: relative;
    padding: 100px 0;
    overflow: hidden;
    background: var(--black);
    color: #fff;
}

.cta-bg-effects {
    position: absolute;
    inset: 0;
    pointer-events: none;
}

.cta-glow {
    position: absolute;
    border-radius: 50%;
    filter: blur(100px);
    opacity: 0.08;
}

.cta-glow-1 {
    width: 400px;
    height: 400px;
    background: var(--coral);
    top: -100px;
    left: 20%;
}

.cta-glow-2 {
    width: 350px;
    height: 350px;
    background: #6366f1;
    bottom: -100px;
    right: 20%;
}

.cta-content {
    position: relative;
    text-align: center;
}

.cta-title {
    font-size: 36px;
    font-weight: 700;
    margin-bottom: 16px;
    color: #fff;
}

.cta-subtitle {
    font-size: 17px;
    color: rgba(255, 255, 255, 0.7);
    margin-bottom: 36px;
}

.cta-section .btn-primary {
    background: #fff;
    color: var(--black);
}

.cta-section .btn-primary:hover {
    background: #f0f0f0;
    box-shadow: 0 6px 20px rgba(255, 255, 255, 0.2);
}

/* ===== Footer ===== */
.footer {
    padding: 60px 0 0;
    border-top: 1px solid var(--border-color);
    background: var(--bg-primary);
}

.footer-grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: 48px;
    padding-bottom: 40px;
}

.footer-brand {
    padding-right: 24px;
}

.footer-logo {
    font-size: 20px;
    font-weight: 700;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    margin-bottom: 14px;
    color: var(--black);
}

.footer-logo i {
    color: var(--black);
}

.footer-desc {
    font-size: 14px;
    color: var(--text-secondary);
    line-height: 1.7;
    margin-bottom: 20px;
}

.footer-socials {
    display: flex;
    gap: 10px;
}

.footer-social {
    width: 38px;
    height: 38px;
    border-radius: 50%;
    background: var(--bg-section-alt);
    border: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 15px;
    color: var(--text-secondary);
    transition: all var(--transition);
}

.footer-social:hover {
    color: var(--black);
    border-color: var(--black);
    background: rgba(0, 0, 0, 0.04);
    transform: translateY(-2px);
}

.footer-nav-title {
    font-size: 14px;
    font-weight: 700;
    color: var(--black);
    margin-bottom: 16px;
    text-transform: uppercase;
    letter-spacing: 0.03em;
}

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

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

.footer-nav-list a {
    font-size: 14px;
    color: var(--text-secondary);
    transition: color var(--transition);
}

.footer-nav-list a:hover {
    color: var(--black);
}

.footer-bottom {
    border-top: 1px solid var(--border-color);
    padding: 20px 0;
    text-align: center;
}

.footer-copy {
    font-size: 13px;
    color: var(--text-muted);
}

/* ===== Back to Top ===== */
.back-to-top {
    position: fixed;
    bottom: 32px;
    right: 32px;
    width: 44px;
    height: 44px;
    border-radius: 50%;
    background: var(--black);
    color: #fff;
    border: none;
    font-size: 16px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    visibility: hidden;
    transform: translateY(10px);
    transition: all var(--transition);
    z-index: 999;
    box-shadow: 0 2px 12px rgba(0, 0, 0, 0.15);
}

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

.back-to-top:hover {
    background: #333;
    transform: translateY(-2px);
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.25);
}

/* ===== Inner Page Styles ===== */
.page-hero {
    padding: 140px 0 60px;
    text-align: center;
    background: var(--bg-section-alt);
}

.page-hero .page-title {
    font-size: 40px;
    font-weight: 700;
    color: var(--black);
    margin-bottom: 12px;
    letter-spacing: -0.02em;
}

.page-hero .page-subtitle {
    font-size: 17px;
    color: var(--text-secondary);
}

.page-content {
    padding: 60px 0 80px;
}

.page-content .container {
    max-width: 860px;
}

.page-content h2 {
    font-size: 24px;
    font-weight: 700;
    color: var(--black);
    margin: 48px 0 16px;
    padding-bottom: 12px;
    border-bottom: 1px solid var(--border-color);
}

.page-content h2:first-child {
    margin-top: 0;
}

.page-content h3 {
    font-size: 18px;
    font-weight: 600;
    color: var(--black);
    margin: 28px 0 12px;
}

.page-content p {
    font-size: 15px;
    color: var(--text-secondary);
    line-height: 1.85;
    margin-bottom: 16px;
}

.page-content ul, .page-content ol {
    padding-left: 24px;
    margin-bottom: 16px;
}

.page-content li {
    font-size: 15px;
    color: var(--text-secondary);
    line-height: 1.85;
    margin-bottom: 8px;
}

.page-content .last-updated {
    font-size: 13px;
    color: var(--text-muted);
    margin-bottom: 32px;
    padding: 10px 16px;
    background: var(--bg-section-alt);
    border-radius: 8px;
    display: inline-block;
}

/* Guide TOC */
.guide-toc {
    background: var(--bg-section-alt);
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    padding: 24px 28px;
    margin-bottom: 40px;
}

.guide-toc h3 {
    font-size: 16px;
    margin: 0 0 14px;
}

.guide-toc ul {
    margin: 0;
    padding-left: 20px;
}

.guide-toc li {
    margin-bottom: 6px;
}

.guide-toc a {
    color: var(--text-secondary);
    font-size: 14px;
}

.guide-toc a:hover {
    color: var(--black);
}

/* Support cards */
.support-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
    margin-bottom: 40px;
}

.support-card {
    text-align: center;
    padding: 36px 24px;
}

.support-card .card-icon {
    margin: 0 auto 16px;
}

/* Feedback form */
.feedback-form {
    max-width: 600px;
}

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

.form-group label {
    display: block;
    font-size: 14px;
    font-weight: 600;
    color: var(--black);
    margin-bottom: 8px;
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 12px 16px;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    font-size: 15px;
    font-family: inherit;
    color: var(--text-primary);
    background: var(--bg-primary);
    transition: border-color var(--transition);
    outline: none;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    border-color: var(--black);
}

.form-group textarea {
    resize: vertical;
    min-height: 120px;
}

.form-submit {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 14px 32px;
    border-radius: 50px;
    font-size: 15px;
    font-weight: 600;
    cursor: pointer;
    border: none;
    background: var(--black);
    color: #fff;
    transition: all var(--transition);
}

.form-submit:hover {
    background: #333;
    transform: translateY(-2px);
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.15);
}

/* ===== Article Page ===== */
.article-meta {
    display: flex;
    align-items: center;
    gap: 16px;
    flex-wrap: wrap;
    margin-bottom: 32px;
    padding-bottom: 24px;
    border-bottom: 1px solid var(--border-color);
}

.article-badge {
    display: inline-block;
    padding: 4px 14px;
    border-radius: 50px;
    font-size: 13px;
    font-weight: 600;
}

.article-date {
    font-size: 14px;
    color: var(--text-muted);
    display: flex;
    align-items: center;
    gap: 6px;
}

.article-nav {
    display: flex;
    justify-content: space-between;
    gap: 16px;
    margin-top: 48px;
    padding-top: 32px;
    border-top: 1px solid var(--border-color);
}

.article-nav a {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    font-size: 14px;
    font-weight: 600;
    color: var(--text-secondary);
    padding: 10px 20px;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    transition: all var(--transition);
}

.article-nav a:hover {
    color: var(--black);
    border-color: var(--black);
}

.article-nav .nav-disabled {
    opacity: 0.3;
    pointer-events: none;
}

/* ===== Responsive ===== */
@media (max-width: 1024px) {
    .grid-4 {
        grid-template-columns: repeat(2, 1fr);
    }

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

    .section-title {
        font-size: 32px;
    }
}

@media (max-width: 768px) {
    .nav-menu {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: rgba(255, 255, 255, 0.98);
        backdrop-filter: blur(20px);
        -webkit-backdrop-filter: blur(20px);
        flex-direction: column;
        padding: 16px 24px;
        border-bottom: 1px solid var(--border-color);
    }

    .nav-menu.active {
        display: flex;
    }

    .nav-toggle {
        display: block;
    }

    .nav-cta {
        display: none;
    }

    .hero {
        padding: 100px 0 48px;
        min-height: auto;
    }

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

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

    .hero-stats {
        gap: 30px;
    }

    .hero-stat-number {
        font-size: 24px;
    }

    .grid-3,
    .grid-4,
    .reviews-grid {
        grid-template-columns: 1fr;
    }

    .section {
        padding: 70px 0;
    }

    .section-title {
        font-size: 28px;
    }

    .reviews-stats {
        gap: 30px;
    }

    .review-stat-number {
        font-size: 28px;
    }

    .footer-grid {
        grid-template-columns: 1fr 1fr;
        gap: 32px;
    }

    .footer-brand {
        grid-column: 1 / -1;
        text-align: center;
        padding-right: 0;
    }

    .footer-socials {
        justify-content: center;
    }

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

    .support-grid {
        grid-template-columns: 1fr;
    }

    .cta-title {
        font-size: 28px;
    }
}

@media (max-width: 480px) {
    .footer-grid {
        grid-template-columns: 1fr;
    }
    .hero-title {
        font-size: 26px;
    }

    .hero-buttons {
        flex-direction: column;
        align-items: center;
    }

    .hero-stats {
        flex-direction: column;
        gap: 20px;
    }

    .btn-lg {
        padding: 14px 28px;
        font-size: 15px;
    }
}