/* Reset & Base */
* { margin: 0; padding: 0; box-sizing: border-box; }
body { 
    font-family: 'PingFang SC', 'Microsoft YaHei', sans-serif; 
    background: #f4f7fb; 
    color: #333; 
    line-height: 1.6; 
    min-height: 100vh; 
    overflow-x: hidden; 
}
a { text-decoration: none; color: inherit; }
ul { list-style: none; }

/* Theme Variables */
:root {
    --liquid-dark: #002244;
    --liquid-primary: #0066cc;
    --liquid-light: #00e5ff;
    --bg-light: #f4f7fb;
    --text-main: #1a2b3c;
}

/* Navigation */
.navbar { 
    display: flex; 
    justify-content: space-between; 
    align-items: center; 
    padding: 15px 5%; 
    background: rgba(255, 255, 255, 0.9); 
    backdrop-filter: blur(2px);
    border-bottom: 1px solid rgba(0, 102, 204, 0.1); 
    position: sticky; 
    top: 0; 
    z-index: 100; 
    box-shadow: 0 4px 20px rgba(0, 102, 204, 0.05);
}
.nav-logo { 
    font-size: 24px; 
    font-weight: 900; 
    color: var(--liquid-primary);
    display: flex;
    align-items: center;
    gap: 8px;
}
.nav-logo svg {
    fill: var(--liquid-primary);
    width: 28px;
    height: 28px;
}
.nav-links { display: flex; gap: 30px; align-items: center; font-weight: bold; }
.nav-links a { color: var(--text-main); transition: color 0.3s; }
.nav-links a:hover { color: var(--liquid-primary); }
.btn-download-nav { 
    padding: 8px 24px; 
    background: linear-gradient(45deg, var(--liquid-primary), var(--liquid-light)); 
    color: #fff !important; 
    border-radius: 30px; 
    box-shadow: 0 4px 15px rgba(0, 102, 204, 0.3);
    transition: all 0.3s; 
}
.btn-download-nav:hover { 
    box-shadow: 0 6px 20px rgba(0, 229, 255, 0.5); 
    transform: translateY(-2px);
}

/* Hero Section - Liquid Flow */
.hero-wrapper {
    position: relative;
    min-height: 90vh;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
    background: #000;
}

/* Liquid Background Animation */
.liquid-bg {
    position: absolute;
    top: -50%; left: -50%; right: -50%; bottom: -50%;
    background: radial-gradient(circle at 50% 50%, #001133, #000);
    z-index: 0;
}
.liquid-bg::before, .liquid-bg::after {
    content: '';
    position: absolute;
    top: 0; left: 0; right: 0; bottom: 0;
    background: 
        radial-gradient(circle at 30% 40%, rgba(0, 102, 204, 0.4) 0%, transparent 40%),
        radial-gradient(circle at 70% 60%, rgba(0, 229, 255, 0.3) 0%, transparent 40%),
        radial-gradient(circle at 40% 80%, rgba(0, 51, 153, 0.5) 0%, transparent 50%);
    filter: url('#liquid-bg-filter');
    animation: liquidMove 15s infinite alternate ease-in-out;
    opacity: 0.8;
}
.liquid-bg::after {
    background: 
        radial-gradient(circle at 60% 30%, rgba(0, 229, 255, 0.4) 0%, transparent 40%),
        radial-gradient(circle at 20% 70%, rgba(0, 102, 204, 0.3) 0%, transparent 40%);
    animation: liquidMove2 20s infinite alternate-reverse ease-in-out;
    opacity: 0.6;
}

@keyframes liquidMove {
    0% { transform: scale(1) translate(0, 0) rotate(0deg); }
    100% { transform: scale(1.2) translate(5%, 5%) rotate(5deg); }
}
@keyframes liquidMove2 {
    0% { transform: scale(1.1) translate(0, 0) rotate(0deg); }
    100% { transform: scale(1.3) translate(-5%, -5%) rotate(-5deg); }
}

.hero-content { 
    z-index: 3; 
    max-width: 1000px; 
    text-align: center;
    padding: 40px;
    display: flex;
    flex-direction: column;
    align-items: center;
}

/* Liquid Text Effect */
.liquid-title-container {
    position: relative;
    margin-bottom: 20px;
    display: inline-block;
}

.liquid-text {
    font-size: 56px; /* Adjusted for longer title */
    font-weight: 900;
    letter-spacing: 2px;
    background: linear-gradient(90deg, #003399, #0088ff, #00e5ff, #0088ff, #003399);
    background-size: 200% auto;
    color: transparent;
    -webkit-background-clip: text;
    background-clip: text;
    animation: flowText 4s linear infinite;
    filter: url('#liquid-text-filter');
    position: relative;
    z-index: 2;
    line-height: 1.3;
}

.paper-plane-svg {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 120px;
    height: 120px;
    fill: #fff;
    z-index: 1;
    opacity: 0.15;
    animation: floatPlane 6s ease-in-out infinite;
}

@keyframes flowText {
    to { background-position: 200% center; }
}
@keyframes floatPlane {
    0%, 100% { transform: translate(-50%, -50%) rotate(-10deg); }
    50% { transform: translate(-50%, -60%) rotate(10deg); }
}

.hero p { 
    font-size: 20px; 
    margin-bottom: 40px; 
    color: #e0f7fa;
    text-shadow: 0 2px 10px rgba(0,0,0,0.5);
    max-width: 700px;
}

.hero-buttons { display: flex; gap: 20px; justify-content: center; margin-bottom: 50px; flex-wrap: wrap; }
.btn-liquid { 
    padding: 15px 35px; 
    font-size: 16px; 
    font-weight: bold; 
    background: rgba(0, 102, 204, 0.2); 
    color: #fff; 
    border: 1px solid rgba(0, 229, 255, 0.5);
    border-radius: 30px;
    backdrop-filter: blur(2px);
    box-shadow: 0 0 15px rgba(0, 229, 255, 0.2);
    transition: all 0.3s;
}
.btn-liquid:hover { 
    background: rgba(0, 229, 255, 0.3); 
    box-shadow: 0 0 25px rgba(0, 229, 255, 0.6); 
    transform: translateY(-3px);
}

.btn-liquid-solid { 
    padding: 15px 35px; 
    font-size: 16px; 
    font-weight: bold; 
    background: linear-gradient(45deg, #0066cc, #00e5ff); 
    color: #fff; 
    border: none;
    border-radius: 30px;
    box-shadow: 0 10px 25px rgba(0, 102, 204, 0.5);
    transition: all 0.3s;
}
.btn-liquid-solid:hover { 
    box-shadow: 0 15px 35px rgba(0, 229, 255, 0.6); 
    transform: translateY(-3px);
}

.hero-images { 
    display: flex; 
    justify-content: center; 
    gap: 20px; 
    z-index: 3; 
    align-items: flex-end; 
}
.hero-images img { 
    max-width: 28%; 
    border-radius: 12px;
    box-shadow: 0 20px 40px rgba(0,0,0,0.4);
    border: 1px solid rgba(255,255,255,0.1);
    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: var(--bg-light); position: relative; }
.features::before {
    content: '';
    position: absolute;
    top: 0; left: 0; right: 0; height: 150px;
    background: linear-gradient(to bottom, #000, transparent);
    opacity: 0.1;
    pointer-events: none;
}
.section-title { text-align: center; font-size: 36px; margin-bottom: 60px; color: var(--liquid-dark); }
.features-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 30px; max-width: 1200px; margin: 0 auto; }

.feature-card { 
    padding: 40px 30px; 
    text-align: center; 
    background: #fff;
    border-radius: 20px;
    box-shadow: 0 10px 30px rgba(0, 102, 204, 0.05);
    transition: all 0.3s; 
    border: 1px solid rgba(0, 102, 204, 0.05);
}
.feature-card:hover { 
    transform: translateY(-10px); 
    box-shadow: 0 20px 40px rgba(0, 102, 204, 0.15); 
    border-color: rgba(0, 229, 255, 0.3);
}
.feature-card h3 { color: var(--liquid-primary); font-size: 22px; margin-bottom: 15px; }
.feature-card p { color: #666; }

/* Blog Section */
.blog { padding: 100px 5%; background: #fff; }
.blog-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 40px; max-width: 1100px; margin: 0 auto; }
.blog-card { 
    display: flex; 
    flex-direction: column; 
    background: var(--bg-light);
    border-radius: 20px;
    overflow: hidden;
    box-shadow: 0 10px 25px rgba(0,0,0,0.03);
    transition: transform 0.3s;
}
.blog-card:hover { transform: translateY(-5px); }
.blog-card img { width: 100%; height: 260px; object-fit: cover; }
.blog-content { padding: 30px; }
.blog-date { display: inline-block; margin-bottom: 15px; font-size: 14px; color: var(--liquid-primary); font-weight: bold; }
.blog-content h3 { font-size: 22px; margin-bottom: 15px; color: var(--liquid-dark); }
.blog-content p { color: #666; margin-bottom: 0; }
.btn-more { 
    display: block; 
    width: 220px; 
    margin: 60px auto 0; 
    text-align: center; 
    padding: 15px; 
    background: var(--liquid-dark);
    color: #fff; 
    font-weight: bold; 
    border-radius: 30px;
    transition: all 0.3s; 
}
.btn-more:hover { background: var(--liquid-primary); box-shadow: 0 10px 20px rgba(0, 102, 204, 0.3); }

/* FAQ Section */
.faq { padding: 100px 5%; max-width: 900px; margin: 0 auto; background: var(--bg-light); margin-bottom: 80px; border-radius: 30px; }
.faq-item { 
    background: #fff; 
    margin-bottom: 20px; 
    padding: 25px 30px; 
    border-radius: 15px;
    box-shadow: 0 5px 15px rgba(0, 102, 204, 0.05);
    border-left: 4px solid var(--liquid-light);
}
.faq-question { font-size: 18px; font-weight: bold; color: var(--liquid-dark); margin-bottom: 12px; }
.faq-question::before { content: 'Q: '; color: var(--liquid-primary); }
.faq-answer { color: #555; font-size: 15px; }

/* Footer */
.footer { background: #001122; padding: 80px 5% 30px; color: #fff; position: relative; overflow: hidden;}
.footer::before {
    content: '';
    position: absolute;
    top: 0; left: 0; right: 0; height: 4px;
    background: linear-gradient(90deg, var(--liquid-primary), var(--liquid-light));
}
.footer-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 40px; max-width: 1200px; margin: 0 auto 50px; position: relative; z-index: 2;}
.footer-col h4 { font-size: 18px; color: #fff; margin-bottom: 25px; font-weight: bold; }
.footer-col ul li { margin-bottom: 15px; }
.footer-col ul li a { color: #88aadd; transition: color 0.3s; }
.footer-col ul li a:hover { color: var(--liquid-light); }
.footer-bottom { text-align: center; padding-top: 30px; border-top: 1px solid rgba(255,255,255,0.1); color: #557799; font-size: 14px; 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 { padding: 40px 30px; text-align: center; background: #fff; border-radius: 20px; box-shadow: 0 10px 30px rgba(0, 102, 204, 0.08); transition: transform 0.3s;}
.download-card:hover { transform: translateY(-5px); }
.download-card h3 { font-size: 22px; margin-bottom: 15px; color: var(--liquid-dark);}
.download-card p { color: #666; margin-bottom: 30px; font-size: 15px; }
.btn-dl-card { display: inline-block; padding: 12px 30px; background: var(--liquid-primary); color: #fff; border-radius: 30px; font-weight: bold; transition: all 0.3s; }
.btn-dl-card:hover { background: var(--liquid-light); box-shadow: 0 5px 15px rgba(0, 229, 255, 0.4); color: #000; }

/* Page specific headers */
.page-header { 
    padding: 120px 5% 80px; 
    text-align: center; 
    background: #001133;
    position: relative;
    overflow: hidden;
}
.page-header::before {
    content: '';
    position: absolute;
    top: 0; left: 0; right: 0; bottom: 0;
    background: radial-gradient(circle at 50% 100%, rgba(0, 102, 204, 0.4) 0%, transparent 60%);
}
.page-header-content {
    position: relative;
    z-index: 2;
    color: #fff;
    max-width: 800px;
    margin: 0 auto;
}
.page-header h1 { font-size: 42px; margin-bottom: 20px; color: var(--liquid-light); }
.page-header p { font-size: 18px; color: #b0d0ff; }

/* === 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;
    }
}