:root {
    --bg: #fdfdfd;
    --surface: #ffffff;
    --surface-hover: #f1f5f9;
    --accent: #3050F4;
    --accent-glow: rgba(48, 80, 244, 0.15);
    --text-primary: #0f172a;
    --text-secondary: #64748b;
    --border: #e2e8f0;
    --nav-bg: rgba(255, 255, 255, 0.8);
    --glass: rgba(255, 255, 255, 0.7);
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", sans-serif;
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    -webkit-font-smoothing: antialiased;
}

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

/* Scrollbar */
::-webkit-scrollbar {
    width: 10px;
}

::-webkit-scrollbar-track {
    background: #f1f1f1;
}

::-webkit-scrollbar-thumb {
    background: #cbd5e1;
    border-radius: 10px;
    border: 2px solid #f1f1f1;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--accent);
}

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

/* Navigation */
nav {
    position: fixed;
    top: 0;
    width: 100%;
    height: 80px;
    background: var(--nav-bg);
    backdrop-filter: blur(16px);
    border-bottom: 1px solid var(--border);
    z-index: 1000;
    transition: all 0.3s;
}

.nav-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 100%;
}

.logo {
    display: flex;
    align-items: center;
    gap: 12px;
    text-decoration: none;
    color: var(--text-primary);
    font-weight: 800;
    font-size: 1.5rem;
    letter-spacing: -0.02em;
}

.logo img {
    height: 40px;
}

.nav-links {
    display: flex;
    gap: 40px;
}

.menu-toggle {
    display: none;
    flex-direction: column;
    gap: 6px;
    cursor: pointer;
    z-index: 1001;
    padding: 10px;
}

.menu-toggle span {
    display: block;
    width: 25px;
    height: 2px;
    background: var(--text-primary);
    transition: 0.3s;
}

/* Mobile Nav */
@media (max-width: 968px) {
    .menu-toggle {
        display: flex;
    }

    .nav-links {
        position: fixed;
        top: 0;
        right: -100%;
        width: 70%;
        height: 100vh;
        background: white;
        flex-direction: column;
        justify-content: center;
        align-items: center;
        gap: 32px;
        transition: 0.4s;
        box-shadow: -10px 0 30px rgba(0, 0, 0, 0.05);
        z-index: 1000;
        padding: 40px;
    }

    .nav-links.active {
        right: 0;
    }

    .nav-links a {
        font-size: 1.2rem;
        font-weight: 700;
        color: var(--text-primary);
    }

    /* Hamburger Animation */
    .menu-toggle.active span:nth-child(1) {
        transform: translateY(8px) rotate(45deg);
    }

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

    .menu-toggle.active span:nth-child(3) {
        transform: translateY(-8px) rotate(-45deg);
    }
}

.nav-links a {
    text-decoration: none;
    color: var(--text-secondary);
    font-size: 0.95rem;
    font-weight: 500;
    transition: all 0.3s;
    position: relative;
}

.nav-links a:hover {
    color: var(--accent);
}

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--accent);
    transition: width 0.3s;
}

.nav-links a:hover::after {
    width: 100%;
}

.download-btn {
    background: var(--accent);
    color: white;
    padding: 10px 24px;
    border-radius: 12px;
    font-weight: 600;
    text-decoration: none;
    transition: all 0.3s;
    box-shadow: 0 4px 14px 0 rgba(48, 80, 244, 0.39);
}

.download-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(48, 80, 244, 0.5);
}

/* Hero Section */
.hero {
    padding-top: 180px;
    padding-bottom: 120px;
    overflow: hidden;
    background: radial-gradient(circle at 70% 20%, rgba(48, 80, 244, 0.05) 0%, transparent 40%),
        radial-gradient(circle at 10% 80%, rgba(48, 80, 244, 0.03) 0%, transparent 40%);
}

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

@media (max-width: 968px) {
    .hero .container {
        grid-template-columns: 1fr;
        text-align: center;
    }
}

.hero-content h1 {
    font-size: 4.5rem;
    line-height: 1.1;
    font-weight: 900;
    letter-spacing: -0.05em;
    margin-bottom: 32px;
    color: var(--text-primary);
}

@media (max-width: 640px) {
    .hero-content h1 {
        font-size: 3rem;
    }
}

.hero-sub {
    font-size: 1.25rem;
    color: var(--text-secondary);
    margin-bottom: 48px;
    line-height: 1.5;
}

.hero-actions {
    display: flex;
    gap: 16px;
}

@media (max-width: 968px) {
    .hero-actions {
        justify-content: center;
    }
}

.btn-primary {
    padding: 16px 40px;
    border-radius: 16px;
    font-weight: 700;
    text-decoration: none;
    background: var(--accent);
    color: white;
    transition: all 0.3s;
    box-shadow: 0 10px 25px -5px rgba(48, 80, 244, 0.4);
}

.btn-primary:hover {
    transform: scale(1.05);
}

.btn-secondary {
    padding: 16px 40px;
    border-radius: 16px;
    font-weight: 700;
    text-decoration: none;
    background: white;
    color: var(--text-primary);
    border: 1px solid var(--border);
    transition: all 0.3s;
}

.btn-secondary:hover {
    background: var(--surface-hover);
}

.hero-image {
    position: relative;
}

.hero-image img {
    width: 100%;
    max-width: 500px;
    border-radius: 32px;
}

/* Bento Grid */
.bento-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    grid-auto-rows: 240px;
    gap: 20px;
}

@media (max-width: 968px) {
    .bento-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 640px) {
    .bento-grid {
        display: grid !important;
        grid-template-columns: repeat(2, 1fr) !important;
        grid-auto-rows: auto !important;
        gap: 8px !important;
        overflow: visible !important;
    }

    .bento-item {
        height: 120px !important;
        border-radius: 4px !important;
    }

    .bento-overlay {
        height: 32px !important;
        background: rgba(0, 0, 0, 0.7) !important;
        padding: 0 8px !important;
        justify-content: center !important;
    }

    .bento-title {
        font-size: 0.75rem !important;
        text-align: center;
        white-space: nowrap !important;
        margin-bottom: 0 !important;
    }

    .bento-desc {
        display: none !important;
    }
}

.bento-item {
    background: #111;
    border-radius: 4px;
    padding: 0;
    transition: all 0.3s ease;
    display: flex;
    flex-direction: column;
    justify-content: flex-end;
    position: relative;
    overflow: hidden;
    height: 100%;
}

.bento-item:hover {
    z-index: 10;
}

.bento-bg {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    object-fit: cover;
    z-index: 1;
}

.bento-overlay {
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    height: 50px;
    background: rgba(0, 0, 0, 0.7);
    z-index: 2;
    transition: all 0.3s ease;
    display: flex;
    flex-direction: column;
    justify-content: center;
    padding: 0 16px;
}

.bento-item:hover .bento-overlay {
    height: 100%;
    background: rgba(0, 0, 0, 0.85);
    padding: 24px;
}

.bento-content {
    width: 100%;
}

.bento-item.large,
.bento-item.medium {
    grid-column: span 1;
    grid-row: span 1;
}

.bento-title {
    font-size: 0.95rem;
    font-weight: 700;
    color: #fff;
    margin: 0;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    line-height: 1.4;
    transition: all 0.3s;
}

.bento-item:hover .bento-title {
    white-space: normal;
    font-size: 1.1rem;
    margin-bottom: 12px;
}

.bento-desc {
    display: block;
    color: rgba(255, 255, 255, 0.9);
    font-size: 0.85rem;
    line-height: 1.6;
    opacity: 0;
    transform: translateY(10px);
    transition: all 0.3s ease 0.1s;
    max-height: 0;
    overflow: hidden;
}

.bento-item:hover .bento-desc {
    opacity: 1;
    transform: translateY(0);
    max-height: 200px;
}

.bento-item .icon {
    display: none;
}

/* Sections */
.section {
    padding: 120px 0;
}

.section-tag {
    color: var(--accent);
    text-transform: uppercase;
    font-weight: 700;
    letter-spacing: 0.1em;
    font-size: 0.85rem;
    display: block;
    margin-bottom: 12px;
    text-align: center;
}

.section-title {
    font-size: 3rem;
    font-weight: 900;
    margin-bottom: 60px;
    text-align: center;
    letter-spacing: -0.03em;
}

/* Stats Strip (Refined) */
.stat-strip {
    padding: 60px 0;
    background: #ffffff;
    border-top: 1px solid var(--border);
    border-bottom: 1px solid var(--border);
}

.stat-strip-grid {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 40px;
}

@media (max-width: 968px) {
    .stat-strip-grid {
        display: grid;
        grid-template-columns: repeat(2, 1fr);
        gap: 30px;
    }
}

.stat-strip-item {
    display: flex;
    align-items: center;
    gap: 16px;
    text-align: left;
}

.stat-strip-item .icon {
    width: 28px;
    height: 28px;
    padding: 0;
    margin-bottom: 0;
    stroke-width: 2.5;
    opacity: 0.8;
}

.stat-strip-info h4 {
    font-size: 1.25rem;
    font-weight: 800;
    line-height: 1;
    color: var(--text-primary);
}

.stat-strip-info p {
    font-size: 0.85rem;
    color: var(--text-secondary);
    margin-top: 4px;
    font-weight: 500;
}

/* Roadmap */
.roadmap {
    width: 100%;
}

.roadmap-item {
    display: grid;
    grid-template-columns: 120px 1fr;
    gap: 40px;
    margin-bottom: 60px;
    position: relative;
}

.roadmap-item::before {
    content: '';
    position: absolute;
    left: 140px;
    top: 0;
    bottom: -60px;
    width: 2px;
    background: var(--border);
}

.roadmap-item:last-child::before {
    display: none;
}

.roadmap-date {
    font-weight: 800;
    color: var(--text-secondary);
    text-align: right;
    padding-top: 4px;
}

.roadmap-content {
    background: white;
    padding: 32px;
    border-radius: 24px;
    border: 1px solid var(--border);
    box-shadow: var(--shadow-sm);
    transition: all 0.3s;
}

.roadmap-content:hover {
    border-color: var(--accent);
    box-shadow: var(--shadow-md);
}

.roadmap-content h4 {
    font-size: 1.25rem;
    margin-bottom: 12px;
    color: var(--text-primary);
}

/* Footer */
footer {
    background: #f8fafc;
    border-top: 1px solid var(--border);
    padding: 60px 0 40px;
}

.footer-content {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 80px;
    margin-bottom: 40px;
}

@media (max-width: 768px) {
    .footer-content {
        grid-template-columns: 1fr !important;
        gap: 32px !important;
    }

    footer {
        padding: 40px 0 30px !important;
    }

    .footer-col .logo {
        justify-content: flex-start !important;
    }
}

.footer-col h4 {
    font-size: 1rem;
    font-weight: 700;
    margin-bottom: 28px;
    color: var(--text-primary);
}

.footer-col ul li {
    list-style: none;
    margin-bottom: 16px;
}

.footer-col ul li a {
    text-decoration: none;
    color: var(--text-secondary);
    font-size: 0.95rem;
    transition: color 0.3s;
}

.footer-col ul li a:hover {
    color: var(--accent);
}

.footer-bottom {
    padding-top: 40px;
    border-top: 1px solid var(--border);
    display: flex;
    justify-content: space-between;
    align-items: center;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

@media (max-width: 640px) {
    .footer-bottom {
        flex-direction: column;
        gap: 20px;
        text-align: center;
    }
}

/* Animations disabled */
[data-anime] {
    opacity: 1;
    transform: none;
}

/* Utility */
.glass {
    background: var(--nav-bg);
    backdrop-filter: blur(12px);
    border: 1px solid var(--border);
}

.bg-accent-soft {
    background-color: var(--accent-glow);
}

.hero-stats-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 16px;
}

@media (max-width: 480px) {
    .hero-image img {
        width: 120px !important;
        height: 120px !important;
        margin-bottom: 20px !important;
    }

    .hero-image h2 {
        font-size: 2rem !important;
        margin-bottom: 32px !important;
    }

    .hero-stats-grid {
        grid-template-columns: repeat(3, 1fr) !important;
        gap: 8px !important;
    }

    .hero-stats-grid div {
        padding: 8px 4px !important;
        border-radius: 12px !important;
        display: flex;
        flex-direction: column;
        align-items: center;
        justify-content: center;
        gap: 2px !important;
    }

    .hero-stats-grid .icon {
        width: 18px !important;
        height: 18px !important;
        margin-bottom: 0 !important;
    }

    .hero-stats-grid div div:first-of-type {
        font-size: 0.7rem !important;
        font-weight: 700;
        margin-bottom: 0 !important;
        line-height: 1.2 !important;
    }

    .hero-stats-grid div div:last-of-type {
        font-size: 0.8rem !important;
        line-height: 1.2 !important;
    }
}

/* Responsive Layout Overrides */
@media (max-width: 1024px) {
    .container {
        padding: 0 32px;
    }
}

.why-us-grid,
.archives-community-grid {
    display: grid;
    grid-template-columns: 1fr 1.5fr;
    gap: 80px;
    align-items: center;
}

.archives-community-grid {
    grid-template-columns: 1.2fr 1.8fr;
    gap: 60px;
    align-items: flex-start;
}

.faq-nav-group {
    display: flex;
    flex-direction: column;
    gap: 40px;
}

.guide-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 40px;
}

@media (max-width: 968px) {

    /* Multi-column grid collapses */
    .faq-grid,
    .guide-grid,
    .why-us-grid,
    .archives-community-grid,
    [style*="grid-template-columns: 280px 1fr"],
    [style*="grid-template-columns: 240px 1fr"] {
        grid-template-columns: 1fr !important;
        gap: 40px !important;
    }

    .why-us-grid {
        text-align: left;
    }

    .faq-nav-group {
        flex-direction: row !important;
        gap: 16px !important;
        align-items: stretch !important;
        margin-bottom: 32px !important;
    }

    .faq-nav-group>* {
        flex: 1;
    }

    /* Fixed sidebars to static */
    aside,
    [style*="position: sticky"] {
        position: static !important;
        width: 100% !important;
    }

    .section-title {
        font-size: 2.5rem;
    }

    header h1,
    .hero-content h1 {
        font-size: 2.8rem !important;
        line-height: 1.2 !important;
    }
}

@media (max-width: 640px) {
    .section {
        padding: 80px 0;
    }

    .section-title {
        font-size: 2rem;
        margin-bottom: 40px;
    }

    .roadmap-item {
        grid-template-columns: 1fr;
        gap: 16px;
    }

    .roadmap-date {
        text-align: left;
        padding-bottom: 0;
    }

    .roadmap-item::before {
        display: none;
    }
}

/* Ultra-wide Optimization */
@media (min-width: 1920px) {
    .container {
        max-width: 1400px;
    }

    body {
        font-size: 18px;
    }
}

/* FAQ Nav Styles */
.faq-nav-link {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 0.95rem;
    display: flex;
    align-items: center;
    gap: 8px;
    transition: all 0.3s ease;
}

.faq-nav-link .dot {
    width: 6px;
    height: 6px;
    background: #ddd;
    border-radius: 50%;
    transition: all 0.3s ease;
}

.faq-nav-link.active {
    color: var(--accent);
    font-weight: 600;
}

.faq-nav-link.active .dot {
    background: var(--accent);
}

.icon {
    width: 32px;
    height: 32px;
    fill: none;
    stroke: var(--accent);
    stroke-width: 2;
    stroke-linecap: round;
    stroke-linejoin: round;
    margin-bottom: 24px;
}

/* Back to Top Button */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 50px;
    height: 50px;
    background: var(--accent);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    box-shadow: 0 4px 12px rgba(48, 80, 244, 0.3);
    z-index: 1000;
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
}

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

.back-to-top:hover {
    transform: translateY(-5px);
    box-shadow: 0 6px 16px rgba(48, 80, 244, 0.4);
}

.back-to-top svg {
    width: 24px;
    height: 24px;
    fill: none;
    stroke: currentColor;
    stroke-width: 2.5;
    stroke-linecap: round;
    stroke-linejoin: round;
}

@media (max-width: 768px) {
    .back-to-top {
        bottom: 20px;
        right: 20px;
        width: 44px;
        height: 44px;
    }
}