/* ==================== Reset & Base ==================== */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; font-size: 16px; }
body {
    font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", sans-serif;
    color: #333; line-height: 1.7; background: #fff;
    -webkit-font-smoothing: antialiased;
}
a { color: #E8600A; text-decoration: none; transition: color .2s; }
a:hover { color: #C84E00; }
img { max-width: 100%; height: auto; display: block; }
ul { list-style: none; }

/* ==================== Variables (CSS custom properties) ==================== */
:root {
    --orange-primary: #E8600A;
    --orange-dark: #C84E00;
    --orange-light: #FF8C42;
    --orange-bg: #FFF5EC;
    --orange-bg2: #FFF0E0;
    --orange-gradient: linear-gradient(135deg, #FF8C42 0%, #E8600A 50%, #C84E00 100%);
    --text-primary: #1A1A2E;
    --text-secondary: #555;
    --text-light: #888;
    --white: #fff;
    --gray-50: #FAFAFA;
    --gray-100: #F5F5F5;
    --gray-200: #E5E5E5;
    --gray-800: #333;
    --shadow-sm: 0 1px 3px rgba(0,0,0,.08);
    --shadow-md: 0 4px 16px rgba(0,0,0,.1);
    --shadow-lg: 0 8px 32px rgba(0,0,0,.12);
    --shadow-xl: 0 16px 48px rgba(0,0,0,.15);
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 24px;
    --max-width: 1100px;
}

/* ==================== Container ==================== */
.container { max-width: var(--max-width); margin: 0 auto; padding: 0 20px; }

/* ==================== Navbar ==================== */
.navbar {
    position: fixed; top: 0; left: 0; right: 0; z-index: 1000;
    background: rgba(255,255,255,.92);
    backdrop-filter: blur(12px); -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid rgba(232,96,10,.08);
    transition: box-shadow .3s;
}
.navbar.scrolled { box-shadow: var(--shadow-sm); }
.navbar .container { display: flex; align-items: center; justify-content: space-between; height: 64px; }
.navbar-brand { display: flex; align-items: center; gap: 10px; font-size: 1.25rem; font-weight: 700; color: var(--orange-primary); }
.navbar-brand img.navbar-logo { width: 36px; height: 36px; border-radius: 8px; object-fit: contain; }
.nav-links { display: flex; align-items: center; gap: 28px; }
.nav-links a { color: var(--text-secondary); font-size: .95rem; font-weight: 500; }
.nav-links a:hover { color: var(--orange-primary); }
.nav-btn {
    background: var(--orange-gradient); color: #fff !important;
    padding: 8px 20px; border-radius: 50px; font-weight: 600; font-size: .9rem;
    box-shadow: 0 4px 12px rgba(232,96,10,.3); transition: transform .2s, box-shadow .2s;
}
.nav-btn:hover { transform: translateY(-1px); box-shadow: 0 6px 20px rgba(232,96,10,.4); color: #fff !important; }

/* Mobile nav toggle */
.nav-toggle { display: none; background: none; border: none; cursor: pointer; padding: 8px; }
.nav-toggle span { display: block; width: 24px; height: 2px; background: var(--gray-800); margin: 6px 0; transition: .3s; border-radius: 2px; }

/* ==================== Hero ==================== */
.hero {
    min-height: 100vh; display: flex; align-items: center; justify-content: center;
    text-align: center; padding: 120px 20px 80px;
    background: linear-gradient(180deg, var(--orange-bg) 0%, #fff 100%);
    position: relative; overflow: hidden;
}
.hero::before {
    content: ''; position: absolute; top: -200px; right: -200px;
    width: 600px; height: 600px; background: radial-gradient(circle, rgba(232,96,10,.08) 0%, transparent 70%);
    border-radius: 50%;
}
.hero::after {
    content: ''; position: absolute; bottom: -150px; left: -150px;
    width: 500px; height: 500px; background: radial-gradient(circle, rgba(255,140,66,.06) 0%, transparent 70%);
    border-radius: 50%;
}
.hero-content { position: relative; z-index: 1; max-width: 750px; }
.hero-badge {
    display: inline-flex; align-items: center; gap: 6px;
    background: var(--orange-bg2); color: var(--orange-dark);
    padding: 6px 16px; border-radius: 50px; font-size: .85rem; font-weight: 600;
    margin-bottom: 24px; border: 1px solid rgba(232,96,10,.15);
}
.hero-badge .dot { width: 8px; height: 8px; background: var(--orange-primary); border-radius: 50%; animation: pulse 2s infinite; }
@keyframes pulse { 0%,100% { opacity: 1; } 50% { opacity: .4; } }
.hero h1 {
    font-size: clamp(2rem, 5vw, 3.2rem); font-weight: 800;
    line-height: 1.25; color: var(--text-primary); margin-bottom: 20px;
}
.hero h1 .highlight {
    background: var(--orange-gradient); -webkit-background-clip: text;
    -webkit-text-fill-color: transparent; background-clip: text;
}
.hero p { font-size: clamp(1rem, 2.5vw, 1.2rem); color: var(--text-secondary); margin-bottom: 36px; max-width: 600px; margin-left: auto; margin-right: auto; }
.hero-actions { display: flex; gap: 16px; justify-content: center; flex-wrap: wrap; }
.btn {
    display: inline-flex; align-items: center; gap: 8px;
    padding: 14px 32px; border-radius: 50px; font-size: 1rem; font-weight: 600;
    border: none; cursor: pointer; transition: all .2s;
}
.btn-primary {
    background: var(--orange-gradient); color: #fff;
    box-shadow: 0 4px 16px rgba(232,96,10,.35);
}
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 8px 24px rgba(232,96,10,.45); color: #fff; }
.btn-outline {
    background: transparent; color: var(--orange-primary);
    border: 2px solid var(--orange-primary);
}
.btn-outline:hover { background: var(--orange-bg); }

/* ========== Download Buttons ========== */
.download-group { display: flex; gap: 12px; justify-content: center; flex-wrap: nowrap; margin-top: 36px; }
.download-group .dl-btn {
    display: inline-flex; align-items: center; gap: 8px;
    padding: 14px 24px; border-radius: 50px; white-space: nowrap;
    font-size: .9rem; font-weight: 600; color: #fff;
    border: none; cursor: pointer; transition: all .2s;
    text-decoration: none;
}
.dl-btn svg { width: 18px; height: 18px; fill: currentColor; flex-shrink: 0; }
.dl-btn-windows { background: var(--orange-gradient); box-shadow: 0 4px 12px rgba(232,96,10,.3); }
.dl-btn-windows:hover { transform: translateY(-2px); box-shadow: 0 6px 20px rgba(232,96,10,.45); color: #fff; }
.dl-btn-mac { background: var(--orange-gradient); box-shadow: 0 4px 12px rgba(232,96,10,.3); }
.dl-btn-mac:hover { transform: translateY(-2px); box-shadow: 0 6px 20px rgba(232,96,10,.45); color: #fff; }
.dl-group-label { font-size: .85rem; color: var(--text-light); margin-bottom: 4px; font-weight: 500; }
.dl-group-wrap { display: flex; flex-direction: column; align-items: center; }
.hero-stats { display: flex; justify-content: center; gap: 48px; margin-top: 48px; padding-top: 32px; border-top: 1px solid var(--gray-200); }
.hero-stat .num { font-size: 1.6rem; font-weight: 800; color: var(--orange-primary); }
.hero-stat .label { font-size: .85rem; color: var(--text-light); margin-top: 4px; }

/* ==================== Section Common ==================== */
section { padding: 80px 0; }
.section-tag {
    display: inline-block; background: var(--orange-bg2); color: var(--orange-dark);
    padding: 4px 14px; border-radius: 50px; font-size: .8rem; font-weight: 600;
    margin-bottom: 12px; letter-spacing: .5px;
}
.section-title { font-size: clamp(1.6rem, 4vw, 2.4rem); font-weight: 800; color: var(--text-primary); margin-bottom: 16px; line-height: 1.3; }
.section-desc { font-size: 1.05rem; color: var(--text-secondary); max-width: 600px; margin-bottom: 48px; }
.section-header { text-align: center; }
.section-header .section-desc { margin-left: auto; margin-right: auto; }

/* ==================== Features ==================== */
.features { background: #fff; }
.features-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.feature-card {
    background: #fff; border: 1px solid var(--gray-200);
    border-radius: var(--radius-lg); padding: 32px;
    transition: all .3s; position: relative; overflow: hidden;
}
.feature-card:hover { border-color: var(--orange-primary); box-shadow: var(--shadow-lg); transform: translateY(-4px); }
.feature-card::after {
    content: ''; position: absolute; top: 0; left: 0; right: 0; height: 3px;
    background: var(--orange-gradient); opacity: 0; transition: opacity .3s;
}
.feature-card:hover::after { opacity: 1; }
.feature-icon {
    width: 52px; height: 52px; border-radius: 14px;
    background: var(--orange-bg); display: flex; align-items: center; justify-content: center;
    font-size: 1.5rem; margin-bottom: 20px;
}
.feature-card h3 { font-size: 1.15rem; font-weight: 700; color: var(--text-primary); margin-bottom: 10px; }
.feature-card p { font-size: .95rem; color: var(--text-secondary); line-height: 1.65; }

/* ==================== Platforms ==================== */
.platforms { background: var(--gray-50); }
.platforms-grid { display: grid; grid-template-columns: repeat(5, 1fr); gap: 20px; }
.platform-card {
    background: #fff; border-radius: var(--radius-md); padding: 28px 16px;
    text-align: center; border: 1px solid var(--gray-200);
    transition: all .3s;
}
.platform-card:hover { box-shadow: var(--shadow-md); border-color: var(--orange-light); transform: translateY(-2px); }
.platform-icon { font-size: 2.2rem; margin-bottom: 12px; }
.platform-card .name { font-size: .95rem; font-weight: 600; color: var(--text-primary); }

/* ==================== Models ==================== */
.models { background: #fff; }
.models-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 24px; }
.model-card {
    background: #fff; border: 1px solid var(--gray-200);
    border-radius: var(--radius-lg); padding: 28px; transition: all .3s;
}
.model-card:hover { border-color: var(--orange-primary); box-shadow: var(--shadow-md); }
.model-header { display: flex; align-items: center; gap: 14px; margin-bottom: 16px; }
.model-logo {
    width: 48px; height: 48px; border-radius: 12px; display: flex;
    align-items: center; justify-content: center; font-size: 1.2rem; font-weight: 700;
    background: var(--orange-bg); color: var(--orange-primary); flex-shrink: 0;
}
.model-header h3 { font-size: 1.05rem; font-weight: 700; color: var(--text-primary); }
.model-header .tag { font-size: .75rem; color: var(--text-light); }
.model-list { padding-left: 0; }
.model-list li {
    position: relative; padding: 4px 0 4px 18px; font-size: .9rem;
    color: var(--text-secondary);
}
.model-list li::before {
    content: '✦'; position: absolute; left: 0; color: var(--orange-primary);
    font-size: .6rem; top: 8px;
}
.model-count { font-size: .8rem; color: var(--orange-primary); font-weight: 600; margin-top: 10px; }

/* ==================== Install Steps ==================== */
.install { background: var(--orange-bg); }
.steps-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 32px; position: relative; }
.step-card { text-align: center; position: relative; }
.step-num {
    width: 56px; height: 56px; border-radius: 50%; background: var(--orange-gradient);
    color: #fff; font-size: 1.4rem; font-weight: 800; display: flex;
    align-items: center; justify-content: center; margin: 0 auto 20px;
    box-shadow: 0 4px 16px rgba(232,96,10,.3);
}
.step-card h3 { font-size: 1.1rem; font-weight: 700; color: var(--text-primary); margin-bottom: 10px; }
.step-card p { font-size: .9rem; color: var(--text-secondary); max-width: 280px; margin: 0 auto; }
.install-download { text-align: center; margin-top: 48px; }
.install-download .download-group { margin-top: 8px; }
.install-download .btn { font-size: 1.1rem; padding: 16px 40px; }

/* ==================== CTA ==================== */
.cta {
    background: var(--orange-gradient); color: #fff;
    text-align: center; padding: 80px 20px;
}
.cta h2 { font-size: clamp(1.6rem, 4vw, 2.4rem); font-weight: 800; margin-bottom: 16px; }
.cta p { font-size: 1.1rem; opacity: .9; margin-bottom: 32px; max-width: 500px; margin-left: auto; margin-right: auto; }
.cta .btn-white {
    background: #fff; color: var(--orange-primary); font-weight: 700;
    box-shadow: 0 4px 16px rgba(0,0,0,.15);
}
.cta .btn-white:hover { transform: translateY(-2px); box-shadow: 0 8px 24px rgba(0,0,0,.2); color: var(--orange-dark); }

/* ==================== FAQ ==================== */
.faq { background: #fff; }
.faq-list { max-width: 750px; margin: 0 auto; }
.faq-item { border-bottom: 1px solid var(--gray-200); }
.faq-q {
    padding: 20px 0; cursor: pointer; display: flex;
    align-items: center; justify-content: space-between;
    font-size: 1.05rem; font-weight: 600; color: var(--text-primary);
}
.faq-q::after { content: '+'; font-size: 1.4rem; color: var(--orange-primary); transition: transform .3s; flex-shrink: 0; margin-left: 16px; }
.faq-item.active .faq-q::after { content: '−'; }
.faq-a { max-height: 0; overflow: hidden; transition: max-height .3s ease, padding .3s ease; }
.faq-item.active .faq-a { max-height: 300px; padding-bottom: 20px; }
.faq-a p { font-size: .95rem; color: var(--text-secondary); line-height: 1.7; }

/* ==================== Footer ==================== */
.footer {
    background: var(--text-primary); color: rgba(255,255,255,.6);
    padding: 48px 20px 32px; text-align: center; font-size: .9rem;
}
.footer-brand { font-size: 1.3rem; font-weight: 700; color: #fff; margin-bottom: 8px; }
.footer-brand img.footer-logo { width: 28px; height: 28px; vertical-align: middle; border-radius: 6px; object-fit: contain; margin-right: 8px; }
.footer-brand span { color: var(--orange-light); }
.footer-tagline { font-size: .9rem; color: rgba(255,255,255,.6); margin-bottom: 20px; }
.footer-links { display: flex; justify-content: center; gap: 24px; margin-bottom: 20px; flex-wrap: wrap; }
.footer-links a { color: rgba(255,255,255,.6); font-size: .9rem; }
.footer-links a:hover { color: #fff; }
.footer-divider { border: none; border-top: 1px solid rgba(255,255,255,.1); margin: 20px 0; }
.footer-copy { font-size: .85rem; }

/* ==================== Responsive ==================== */
@media (max-width: 900px) {
    .features-grid { grid-template-columns: repeat(2, 1fr); }
    .platforms-grid { grid-template-columns: repeat(3, 1fr); }
    .models-grid { grid-template-columns: 1fr; }
    .hero-stats { gap: 28px; }
}
@media (max-width: 640px) {
    .nav-links {
        display: none; position: absolute; top: 64px; left: 0; right: 0;
        background: #fff; flex-direction: column; padding: 20px;
        border-bottom: 1px solid var(--gray-200); box-shadow: var(--shadow-md);
    }
    .nav-links.open { display: flex; }
    .nav-toggle { display: block; }
    .features-grid { grid-template-columns: 1fr; }
    .platforms-grid { grid-template-columns: repeat(3, 1fr); }
    .steps-grid { grid-template-columns: 1fr; gap: 24px; }
    .hero { min-height: auto; padding: 120px 20px 60px; }
    .hero-stats { flex-direction: column; gap: 16px; align-items: center; }
    .hero-actions { flex-direction: column; align-items: center; }
    .download-group { flex-direction: column; align-items: center; gap: 8px; }
    .download-group .dl-btn { width: 100%; max-width: 280px; justify-content: center; font-size: .88rem; padding: 12px 20px; }
    .btn { width: 100%; max-width: 300px; justify-content: center; }
    section { padding: 60px 0; }
}
@media (max-width: 400px) {
    .platforms-grid { grid-template-columns: repeat(2, 1fr); }
}

/* ==================== Animations ==================== */
.fade-up { opacity: 0; transform: translateY(30px); transition: opacity .6s ease, transform .6s ease; }
.fade-up.visible { opacity: 1; transform: translateY(0); }