:root {
    --bg-color: #ffffff;
    --text-main: #1a1a2e;
    --text-muted: #4a5568;
    --brand-color: #1a73e8;
    --brand-hover: #1557b0;
    --brand-light: #e8f0fe;
    --surface-light: #f7f8fa;
    --border-color: #e2e8f0;
    --accent-warm: #f59e0b;
    --card-shadow: 0 1px 3px rgba(0, 0, 0, 0.04), 0 1px 2px rgba(0, 0, 0, 0.06);
    --card-shadow-hover: 0 10px 25px rgba(26, 115, 232, 0.08), 0 4px 10px rgba(0, 0, 0, 0.04);
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "PingFang SC", "Microsoft YaHei", sans-serif;
    color: var(--text-main);
    background-color: var(--bg-color);
    line-height: 1.7;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

header {
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    background: rgba(255, 255, 255, 0.92);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    z-index: 100;
    box-shadow: 0 1px 0 rgba(0, 0, 0, 0.02);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 14px 24px;
}

.logo-box {
    display: flex;
    align-items: center;
    gap: 10px;
    text-decoration: none;
    transition: opacity 0.2s;
}

.logo-box:hover {
    opacity: 0.85;
}

.logo-box svg {
    width: 30px;
    height: 30px;
    fill: var(--brand-color);
}

.logo-text {
    font-size: 20px;
    font-weight: 700;
    color: var(--brand-color);
    letter-spacing: -0.3px;
}

nav {
    display: flex;
    gap: 28px;
}

nav a {
    text-decoration: none;
    color: var(--text-muted);
    font-weight: 500;
    transition: color 0.2s;
    font-size: 14.5px;
    position: relative;
}

nav a:hover,
nav a.active {
    color: var(--brand-color);
}

nav a.active::after {
    content: '';
    position: absolute;
    bottom: -6px;
    left: 0;
    right: 0;
    height: 2px;
    background: var(--brand-color);
    border-radius: 1px;
}

.hero {
    max-width: 860px;
    margin: 0 auto;
    text-align: center;
    padding: 60px 24px 36px 24px;
}

.hero h1 {
    font-size: 44px;
    font-weight: 800;
    letter-spacing: -1.2px;
    margin-bottom: 18px;
    line-height: 1.25;
    color: #0f172a;
}

.hero p {
    font-size: 17px;
    color: var(--text-muted);
    max-width: 680px;
    margin: 0 auto 32px auto;
    line-height: 1.8;
}

.hero-btns {
    display: flex;
    justify-content: center;
    align-items: center;
    flex-wrap: wrap;
    gap: 12px;
    margin-bottom: 44px;
}

.btn-primary {
    background-color: var(--brand-color);
    color: #fff;
    padding: 14px 30px;
    border-radius: var(--radius-sm);
    text-decoration: none;
    font-weight: 600;
    font-size: 15px;
    transition: background-color 0.2s, transform 0.1s, box-shadow 0.2s;
    box-shadow: 0 2px 8px rgba(26, 115, 232, 0.2);
}

.btn-primary:hover {
    background-color: var(--brand-hover);
    box-shadow: 0 4px 14px rgba(26, 115, 232, 0.3);
    transform: translateY(-1px);
}

.btn-github {
    background-color: #24292e;
    color: #fff;
    padding: 14px 22px;
    border-radius: var(--radius-sm);
    text-decoration: none;
    font-weight: 600;
    font-size: 14.5px;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    transition: background-color 0.2s, transform 0.1s, box-shadow 0.2s;
    box-shadow: 0 2px 8px rgba(36, 41, 46, 0.2);
}

.btn-github:hover {
    background-color: #1b1f23;
    box-shadow: 0 4px 14px rgba(36, 41, 46, 0.3);
    transform: translateY(-1px);
}

.btn-github svg {
    flex-shrink: 0;
}

.btn-secondary {
    background-color: var(--surface-light);
    color: var(--text-main);
    padding: 14px 30px;
    border-radius: var(--radius-sm);
    text-decoration: none;
    font-weight: 600;
    font-size: 15px;
    transition: background-color 0.2s, transform 0.1s;
    border: 1px solid var(--border-color);
}

.btn-secondary:hover {
    background-color: var(--border-color);
    transform: translateY(-1px);
}

.banner-placeholder {
    width: 100%;
    height: 420px;
    background-color: #fafbfc;
    border: 1px dashed var(--border-color);
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    color: #9ca3af;
    font-size: 14px;
    margin-bottom: 36px;
    overflow: hidden;
}

.banner-placeholder img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.video-container {
    width: 100%;
    max-width: 720px;
    margin: 0 auto 56px auto;
    aspect-ratio: 16/9;
    background-color: #111827;
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
    box-shadow: var(--card-shadow);
}

.video-container iframe {
    width: 100%;
    height: 100%;
    border: none;
}

.section-matrix {
    background-color: #fafbfc;
    border-top: 1px solid var(--border-color);
    border-bottom: 1px solid var(--border-color);
    padding: 72px 24px;
}

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

.section-title {
    font-size: 30px;
    font-weight: 700;
    text-align: center;
    margin-bottom: 14px;
    color: #0f172a;
    letter-spacing: -0.5px;
}

.section-subtitle {
    text-align: center;
    color: var(--text-muted);
    font-size: 15.5px;
    max-width: 580px;
    margin: 0 auto 44px auto;
    line-height: 1.7;
}

.matrix-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 28px;
}

@media (max-width: 900px) {
    .matrix-grid {
        grid-template-columns: 1fr 1fr;
    }
    .hero h1 {
        font-size: 34px;
    }
}

@media (max-width: 640px) {
    .matrix-grid {
        grid-template-columns: 1fr;
    }
    nav {
        display: none;
    }
    .hero h1 {
        font-size: 28px;
    }
    .hero-btns {
        flex-direction: column;
        align-items: stretch;
    }
    .hero-btns .btn-primary,
    .hero-btns .btn-github,
    .hero-btns .btn-secondary {
        text-align: center;
        justify-content: center;
    }
    .banner-placeholder {
        height: 240px;
    }
}

.matrix-card {
    background: #fff;
    padding: 30px 28px;
    border-radius: var(--radius-md);
    border: 1px solid var(--border-color);
    transition: transform 0.25s, box-shadow 0.25s;
    box-shadow: var(--card-shadow);
}

.matrix-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--card-shadow-hover);
    border-color: #cbd5e1;
}

.matrix-card h3 {
    font-size: 18px;
    margin-bottom: 10px;
    color: #0f172a;
    font-weight: 700;
}

.matrix-card p {
    font-size: 14px;
    color: var(--text-muted);
    margin-bottom: 18px;
    line-height: 1.65;
}

.matrix-card a {
    font-size: 14px;
    color: var(--brand-color);
    text-decoration: none;
    font-weight: 600;
    transition: color 0.2s;
}

.matrix-card a:hover {
    color: var(--brand-hover);
}

.deep-feature-section {
    max-width: 1200px;
    margin: 0 auto;
    padding: 72px 24px;
}

.feature-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 56px;
    align-items: start;
    margin-bottom: 64px;
}

.feature-row:last-child {
    margin-bottom: 0;
}

@media (max-width: 768px) {
    .feature-row {
        grid-template-columns: 1fr;
        gap: 32px;
    }
}

.feature-content h2 {
    font-size: 27px;
    font-weight: 700;
    margin-bottom: 18px;
    color: #0f172a;
    letter-spacing: -0.4px;
}

.feature-content p {
    font-size: 15px;
    color: var(--text-muted);
    margin-bottom: 14px;
    line-height: 1.75;
}

.feature-list {
    list-style: none;
    margin-top: 8px;
}

.feature-list li {
    position: relative;
    padding-left: 26px;
    font-size: 14.5px;
    margin-bottom: 10px;
    color: var(--text-main);
    line-height: 1.6;
}

.feature-list li::before {
    content: "✓";
    position: absolute;
    left: 0;
    color: var(--brand-color);
    font-weight: bold;
    font-size: 13px;
}

.history-section {
    background-color: #fafbfc;
    border-top: 1px solid var(--border-color);
    padding: 72px 24px;
}

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

.history-layout {
    display: grid;
    grid-template-columns: 7fr 5fr;
    gap: 52px;
}

@media (max-width: 768px) {
    .history-layout {
        grid-template-columns: 1fr;
    }
}

.history-text h2 {
    font-size: 26px;
    font-weight: 700;
    margin-bottom: 18px;
    color: #0f172a;
}

.history-text p {
    font-size: 15px;
    color: var(--text-muted);
    margin-bottom: 14px;
    line-height: 1.75;
}

.news-sidebar {
    border-left: 3px solid var(--brand-color);
    padding-left: 22px;
    background: #fff;
    padding: 24px 22px;
    border-radius: 0 var(--radius-md) var(--radius-md) 0;
    box-shadow: var(--card-shadow);
}

.news-sidebar h2 {
    font-size: 19px;
    margin-bottom: 22px;
    color: #0f172a;
}

.news-item {
    margin-bottom: 20px;
    padding-bottom: 16px;
    border-bottom: 1px solid var(--border-color);
}

.news-item:last-child {
    margin-bottom: 0;
    padding-bottom: 0;
    border-bottom: none;
}

.news-date {
    font-size: 12.5px;
    font-weight: 700;
    color: var(--brand-color);
    margin-bottom: 4px;
    letter-spacing: 0.3px;
}

.news-title {
    font-size: 14.5px;
    font-weight: 600;
    margin-bottom: 5px;
    color: #1a1a2e;
}

.news-desc {
    font-size: 13px;
    color: var(--text-muted);
    line-height: 1.55;
}

footer {
    border-top: 1px solid var(--border-color);
    padding: 64px 24px 36px 24px;
    background-color: #111827;
    color: #9ca3af;
}

.footer-grid {
    max-width: 1200px;
    margin: 0 auto 52px auto;
    display: grid;
    grid-template-columns: 2fr repeat(4, 1fr);
    gap: 36px;
}

@media (max-width: 900px) {
    .footer-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

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

.footer-brand h4 {
    color: #fff;
    font-size: 17px;
    margin-bottom: 14px;
    display: flex;
    align-items: center;
    gap: 8px;
    font-weight: 700;
}

.footer-brand h4 svg {
    width: 22px;
    height: 22px;
    fill: var(--brand-color);
}

.footer-brand p {
    font-size: 13.5px;
    line-height: 1.7;
    color: #9ca3af;
}

.footer-col h5 {
    color: #fff;
    font-size: 14px;
    margin-bottom: 18px;
    font-weight: 600;
    letter-spacing: 0.2px;
}

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

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

.footer-col ul li a {
    color: #9ca3af;
    text-decoration: none;
    font-size: 13.5px;
    transition: color 0.2s;
}

.footer-col ul li a:hover {
    color: #fff;
}

.footer-bottom {
    max-width: 1200px;
    margin: 0 auto;
    padding-top: 26px;
    border-top: 1px solid #1f2937;
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 13px;
}

@media (max-width: 640px) {
    .footer-bottom {
        flex-direction: column;
        gap: 14px;
        text-align: center;
    }
}

.footer-bottom-links {
    display: flex;
    gap: 20px;
    flex-wrap: wrap;
}

.footer-bottom-links a {
    color: #9ca3af;
    text-decoration: none;
    font-size: 13px;
    transition: color 0.2s;
}

.footer-bottom-links a:hover {
    color: #fff;
}