/* Reset & Base */
* { margin: 0; padding: 0; box-sizing: border-box; }
body { font-family: 'PingFang SC', 'Microsoft YaHei', sans-serif; background: #87CEEB; color: #333; line-height: 1.6; min-height: 100vh; overflow-x: hidden; }
a { text-decoration: none; color: inherit; }
ul { list-style: none; }

/* Flight Theme Variables */
:root {
    --sky-blue: #87CEEB;
    --cloud-white: #ffffff;
    --plane-blue: #2196F3;
    --text-dark: #2c3e50;
    --text-light: #7f8c8d;
    --accent-orange: #FF9800;
}

/* Navigation */
.navbar { display: flex; justify-content: space-between; align-items: center; padding: 15px 5%; background: rgba(255, 255, 255, 0.9); border-bottom: 2px solid rgba(255, 255, 255, 0.5); position: sticky; top: 0; z-index: 100; box-shadow: 0 4px 15px rgba(0,0,0,0.05); backdrop-filter: blur(2px); }
.nav-logo { font-size: 26px; font-weight: 900; color: var(--plane-blue); display: flex; align-items: center; gap: 10px; }
.nav-links { display: flex; gap: 30px; align-items: center; font-weight: bold; }
.nav-links a { font-size: 16px; transition: all 0.3s; color: var(--text-dark); }
.nav-links a:hover { color: var(--plane-blue); }
.btn-download-nav { padding: 8px 24px; background: var(--plane-blue); border-radius: 30px; color: #fff !important; box-shadow: 0 4px 10px rgba(33, 150, 243, 0.3); transition: all 0.3s; }
.btn-download-nav:hover { background: #1976D2; transform: translateY(-2px); box-shadow: 0 6px 15px rgba(33, 150, 243, 0.4); }

/* Hero Section - Flight Simulator */
.hero { position: relative; padding: 60px 5% 40px; text-align: center; overflow: hidden; min-height: 85vh; display: flex; flex-direction: column; justify-content: center; align-items: center; background: linear-gradient(to bottom, #4facfe 0%, #00f2fe 100%); }

/* Clouds Animation */
.clouds { position: absolute; top: 0; left: 0; width: 100%; height: 100%; z-index: 0; pointer-events: none; }
.cloud { position: absolute; background: #fff; border-radius: 50px; opacity: 0.8; animation: moveClouds linear infinite; }
.cloud::before, .cloud::after { content: ''; position: absolute; background: #fff; border-radius: 50%; }
.cloud1 { width: 100px; height: 30px; top: 10%; left: -100px; animation-duration: 25s; }
.cloud1::before { width: 40px; height: 40px; top: -15px; left: 15px; }
.cloud1::after { width: 30px; height: 30px; top: -10px; left: 50px; }
.cloud2 { width: 150px; height: 40px; top: 30%; left: -150px; animation-duration: 35s; animation-delay: 5s; opacity: 0.6; transform: scale(1.2); }
.cloud2::before { width: 60px; height: 60px; top: -25px; left: 20px; }
.cloud2::after { width: 45px; height: 45px; top: -15px; left: 70px; }
.cloud3 { width: 80px; height: 25px; top: 60%; left: -80px; animation-duration: 20s; animation-delay: 2s; opacity: 0.9; }
.cloud3::before { width: 30px; height: 30px; top: -10px; left: 10px; }
.cloud3::after { width: 25px; height: 25px; top: -8px; left: 40px; }
@keyframes moveClouds { 0% { left: -150px; } 100% { left: 100%; } }

/* Interactive Plane */
.interactive-plane { position: absolute; top: 40%; left: 10%; z-index: 2; width: 60px; height: 60px; animation: floatPlane 3s ease-in-out infinite; cursor: pointer; transition: transform 0.3s; }
.interactive-plane:hover { transform: scale(1.2) rotate(-10deg); }
.interactive-plane svg { width: 100%; height: 100%; fill: #fff; filter: drop-shadow(0 5px 5px rgba(0,0,0,0.2)); }
@keyframes floatPlane { 0%, 100% { transform: translateY(0); } 50% { transform: translateY(-20px); } }
.plane-trail { position: absolute; top: 50%; right: 100%; width: 150px; height: 2px; background: linear-gradient(to right, transparent, rgba(255,255,255,0.8)); }

.hero-content { z-index: 3; max-width: 900px; margin: 0 auto; position: relative; background: rgba(255,255,255,0.1); padding: 40px; border-radius: 20px; backdrop-filter: blur(2px); border: 1px solid rgba(255,255,255,0.3); box-shadow: 0 15px 35px rgba(0,0,0,0.1); }
.hero h1 { font-size: 38px; margin-bottom: 20px; color: #fff; text-shadow: 0 2px 10px rgba(0,0,0,0.2); line-height: 1.4; }
.hero p { font-size: 20px; margin-bottom: 40px; color: #f0f8ff; font-weight: 500; }

.hero-buttons { display: flex; gap: 20px; justify-content: center; margin-bottom: 30px; flex-wrap: wrap; }
.btn-fly { padding: 15px 35px; font-size: 18px; font-weight: bold; background: #fff; color: var(--plane-blue); border-radius: 30px; box-shadow: 0 10px 20px rgba(0,0,0,0.15); transition: all 0.3s; cursor: pointer; border: none; }
.btn-fly:hover { transform: translateY(-5px); box-shadow: 0 15px 25px rgba(0,0,0,0.2); background: #f8f9fa; }
.btn-pc { background: var(--accent-orange); color: #fff; }
.btn-pc:hover { background: #F57C00; color: #fff; }

.hero-images { display: flex; justify-content: center; gap: 20px; margin-top: 30px; z-index: 3; align-items: flex-end; }
.hero-images img { max-width: 28%; border-radius: 12px; box-shadow: 0 15px 30px rgba(0,0,0,0.2); border: 3px solid #fff; transition: transform 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275); }
.hero-images img:hover { transform: translateY(-15px) scale(1.05); }

/* Features Section */
.features { padding: 100px 5%; background: #f8f9fa; position: relative; }
.section-title { text-align: center; font-size: 38px; margin-bottom: 60px; color: var(--text-dark); }
.features-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 40px; max-width: 1200px; margin: 0 auto; }
.feature-card { background: #fff; padding: 40px 30px; border-radius: 16px; box-shadow: 0 10px 30px rgba(0,0,0,0.05); transition: all 0.3s; text-align: center; border-bottom: 4px solid transparent; }
.feature-card:hover { transform: translateY(-10px); box-shadow: 0 15px 40px rgba(33, 150, 243, 0.15); border-bottom-color: var(--plane-blue); }
.feature-card h3 { font-size: 22px; margin-bottom: 15px; color: var(--plane-blue); }
.feature-card p { color: var(--text-light); font-size: 15px; line-height: 1.7; }

/* Blog Section */
.blog { padding: 100px 5%; background: #fff; }
.blog-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 50px; max-width: 1100px; margin: 0 auto; }
.blog-card { background: #fff; border-radius: 16px; box-shadow: 0 10px 30px rgba(0,0,0,0.08); transition: all 0.3s; display: flex; flex-direction: column; overflow: hidden; border: 1px solid #edf2f7; }
.blog-card:hover { transform: translateY(-8px); box-shadow: 0 20px 40px rgba(0,0,0,0.12); }
.blog-card img { width: 100%; height: 260px; object-fit: cover; }
.blog-content { padding: 30px; }
.blog-date { display: inline-block; color: var(--accent-orange); font-size: 14px; font-weight: bold; margin-bottom: 15px; }
.blog-content h3 { font-size: 22px; margin-bottom: 15px; color: var(--text-dark); }
.blog-content p { color: var(--text-light); margin-bottom: 0; }
.btn-more { display: block; width: 220px; margin: 60px auto 0; text-align: center; padding: 14px; background: #fff; color: var(--plane-blue); border: 2px solid var(--plane-blue); border-radius: 30px; font-weight: bold; transition: all 0.3s; }
.btn-more:hover { background: var(--plane-blue); color: #fff; box-shadow: 0 10px 20px rgba(33, 150, 243, 0.2); }

/* FAQ Section */
.faq { padding: 100px 5%; max-width: 900px; margin: 0 auto; background: #f8f9fa; border-radius: 20px; margin-bottom: 80px; }
.faq-item { background: #fff; margin-bottom: 20px; border-radius: 12px; padding: 25px 30px; box-shadow: 0 5px 15px rgba(0,0,0,0.03); transition: all 0.3s; border-left: 4px solid transparent; }
.faq-item:hover { box-shadow: 0 8px 25px rgba(0,0,0,0.08); border-left-color: var(--accent-orange); transform: translateX(5px); }
.faq-question { font-size: 18px; font-weight: bold; color: var(--text-dark); margin-bottom: 12px; display: flex; align-items: center; gap: 10px; }
.faq-question::before { content: 'Q:'; color: var(--plane-blue); font-size: 22px; }
.faq-answer { color: var(--text-light); line-height: 1.8; font-size: 15px; padding-left: 32px; }

/* Footer */
.footer { background: #1a252f; padding: 80px 5% 30px; color: #fff; }
.footer-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 40px; max-width: 1200px; margin: 0 auto 50px; }
.footer-col h4 { font-size: 18px; color: #fff; margin-bottom: 25px; font-weight: bold; position: relative; padding-bottom: 10px; }
.footer-col h4::after { content: ''; position: absolute; bottom: 0; left: 0; width: 30px; height: 2px; background: var(--plane-blue); }
.footer-col ul li { margin-bottom: 12px; }
.footer-col ul li a { color: #95a5a6; transition: color 0.3s; }
.footer-col ul li a:hover { color: #fff; padding-left: 5px; }
.footer-bottom { text-align: center; padding-top: 30px; border-top: 1px solid rgba(255,255,255,0.1); color: #7f8c8d; font-size: 14px; }

/* Page specific headers */
.page-header { padding: 120px 5% 80px; text-align: center; background: linear-gradient(to bottom, #4facfe 0%, #00f2fe 100%); position: relative; overflow: hidden; }
.page-header h1 { font-size: 42px; color: #fff; margin-bottom: 20px; text-shadow: 0 2px 10px rgba(0,0,0,0.2); position: relative; z-index: 2; }
.page-header p { color: #f0f8ff; font-size: 18px; max-width: 600px; margin: 0 auto; position: relative; z-index: 2; }

/* Download Page Grid */
.download-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); gap: 30px; max-width: 1100px; margin: 60px auto; padding: 0 5%; }
.download-card { background: #fff; border-radius: 16px; padding: 40px 30px; text-align: center; box-shadow: 0 10px 30px rgba(0,0,0,0.08); transition: all 0.3s; border-top: 5px solid var(--plane-blue); }
.download-card:hover { transform: translateY(-10px); box-shadow: 0 20px 40px rgba(33, 150, 243, 0.2); }
.download-card h3 { color: var(--text-dark); font-size: 24px; margin-bottom: 15px; }
.download-card p { color: var(--text-light); margin-bottom: 30px; font-size: 15px; }
.download-card .btn-fly { display: inline-block; padding: 12px 30px; font-size: 16px; background: var(--plane-blue); color: #fff; }
.download-card .btn-fly:hover { background: #1976D2; }

/* === perf: reduce motion & lower GPU cost === */
.feature-card,
.blog-card,
.hero-content,
.glass-panel,
.pearl-card {
    backdrop-filter: none !important;
    -webkit-backdrop-filter: none !important;
}
.navbar {
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
}
@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        animation: none !important;
        transition: none !important;
        scroll-behavior: auto !important;
    }
}

/* perf: limit decorative infinite layers on mid/low-end devices */
@media (max-width: 768px) {
    .bubble:nth-child(n+3),
    .tiny-plane:nth-child(n+3),
    .bg-shard:nth-child(n+4),
    .orb:nth-child(n+2) {
        display: none !important;
    }
}