/* Reset & Base */
* { margin: 0; padding: 0; box-sizing: border-box; }
body { 
    font-family: 'Consolas', 'Courier New', 'Microsoft YaHei', 'PingFang SC', monospace; 
    /* Blueprint Background */
    background-color: #0b3b73; 
    background-image: 
        linear-gradient(rgba(255, 255, 255, 0.15) 1px, transparent 1px),
        linear-gradient(90deg, rgba(255, 255, 255, 0.15) 1px, transparent 1px),
        linear-gradient(rgba(255, 255, 255, 0.05) 1px, transparent 1px),
        linear-gradient(90deg, rgba(255, 255, 255, 0.05) 1px, transparent 1px);
    background-size: 100px 100px, 100px 100px, 20px 20px, 20px 20px;
    background-position: center center;
    color: #f0f8ff; 
    line-height: 1.6; 
    min-height: 100vh; 
    overflow-x: hidden; 
}
a { text-decoration: none; color: inherit; }
ul { list-style: none; }

/* Theme Variables - Blueprint */
:root {
    --bp-blue: #0b3b73;
    --bp-dark: #062347;
    --bp-accent: #00ffff; /* Cyan for drafting lines */
    --bp-white: #ffffff;
    --text-main: #f0f8ff;
    --text-muted: #a0c4e8;
    --border-color: rgba(0, 255, 255, 0.3);
}

/* Navigation */
.navbar { 
    display: flex; 
    justify-content: space-between; 
    align-items: center; 
    padding: 15px 5%; 
    background: rgba(6, 35, 71, 0.85); 
    backdrop-filter: blur(2px);
    position: sticky; 
    top: 0; 
    z-index: 100; 
    border-bottom: 1px solid var(--border-color);
}
.nav-logo { 
    font-size: 26px; 
    font-weight: bold; 
    display: flex;
    align-items: center;
    gap: 12px;
    color: var(--bp-white);
    letter-spacing: 2px;
}
.nav-logo svg {
    width: 36px;
    height: 36px;
    fill: none;
    stroke: var(--bp-accent);
    stroke-width: 2;
}
.nav-links { display: flex; gap: 30px; align-items: center; font-weight: bold; }
.nav-links a { 
    color: var(--text-muted); 
    transition: all 0.3s; 
    font-size: 16px; 
    position: relative;
    text-transform: uppercase;
}
.nav-links a::after {
    content: '';
    position: absolute;
    bottom: -5px; left: 0; width: 0; height: 2px;
    background: var(--bp-accent);
    transition: width 0.3s ease;
}
.nav-links a:hover { color: var(--bp-accent); }
.nav-links a:hover::after { width: 100%; }

.btn-download-nav { 
    padding: 8px 20px !important; 
    background: transparent;
    color: var(--bp-accent) !important; 
    border: 1px solid var(--bp-accent);
    border-radius: 4px;
    transition: all 0.3s; 
    font-family: inherit;
}
.btn-download-nav::after { display: none; }
.btn-download-nav:hover { 
    background: var(--bp-accent);
    color: var(--bp-dark) !important;
    box-shadow: 0 0 15px rgba(0, 255, 255, 0.4);
}

/* Hero Section - Blueprint */
.hero-wrapper {
    position: relative;
    min-height: 90vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: flex-start;
    padding: 60px 5% 100px;
    overflow: hidden;
}

/* Blueprint Drafting Graphics */
.blueprint-graphics {
    position: absolute;
    top: 0; left: 0; width: 100%; height: 100%;
    pointer-events: none;
    z-index: 0;
}
.draft-line {
    position: absolute;
    background: var(--border-color);
}
.draft-line.v { width: 1px; height: 100%; top: 0; }
.draft-line.h { height: 1px; width: 100%; left: 0; }
.draft-text {
    position: absolute;
    color: var(--bp-accent);
    font-size: 12px;
    opacity: 0.7;
    font-family: 'Courier New', monospace;
}

/* Central Blueprint Plane SVG */
.hero-plane-svg {
    position: absolute;
    top: 50%; left: 50%;
    transform: translate(-50%, -50%);
    width: 800px;
    height: 600px;
    z-index: 1;
    opacity: 0.6;
}
.hero-plane-svg path, .hero-plane-svg polygon, .hero-plane-svg line {
    fill: none;
    stroke: var(--bp-white);
    stroke-width: 1.5;
}
.hero-plane-svg .measure-line {
    stroke: var(--bp-accent);
    stroke-width: 1;
    stroke-dasharray: 4 4;
}
.hero-plane-svg text {
    fill: var(--bp-accent);
    font-size: 14px;
    font-family: 'Courier New', monospace;
}

.hero-content { 
    z-index: 20; 
    max-width: 900px; 
    text-align: center;
    position: relative;
    margin-top: 40px;
    background: rgba(6, 35, 71, 0.6);
    padding: 40px;
    border: 1px solid var(--border-color);
    backdrop-filter: blur(2px);
}
/* Corner markers for content box */
.hero-content::before, .hero-content::after {
    content: ''; position: absolute; width: 15px; height: 15px; border: 2px solid var(--bp-accent);
}
.hero-content::before { top: -2px; left: -2px; border-right: none; border-bottom: none; }
.hero-content::after { bottom: -2px; right: -2px; border-left: none; border-top: none; }

.hero-title {
    font-size: 42px; 
    font-weight: bold;
    margin-bottom: 20px;
    color: var(--bp-white);
    letter-spacing: 2px;
}

.hero p { 
    font-size: 18px; 
    margin-bottom: 40px; 
    color: var(--text-muted);
    max-width: 700px;
    margin-left: auto;
    margin-right: auto;
}

.hero-buttons { display: flex; gap: 20px; justify-content: center; margin-bottom: 50px; flex-wrap: wrap; }

.btn-primary { 
    padding: 14px 30px; 
    font-size: 16px; 
    font-weight: bold; 
    color: var(--bp-dark); 
    background: var(--bp-accent);
    border: 1px solid var(--bp-accent);
    transition: all 0.3s;
    text-transform: uppercase;
    letter-spacing: 1px;
}
.btn-primary:hover { 
    box-shadow: 0 0 20px rgba(0, 255, 255, 0.6);
    background: var(--bp-white);
    border-color: var(--bp-white);
}

.btn-outline { 
    padding: 14px 30px; 
    font-size: 16px; 
    font-weight: bold; 
    color: var(--bp-accent); 
    background: transparent;
    border: 1px solid var(--bp-accent);
    transition: all 0.3s;
    text-transform: uppercase;
    letter-spacing: 1px;
}
.btn-outline:hover { 
    background: rgba(0, 255, 255, 0.1);
    box-shadow: inset 0 0 10px rgba(0, 255, 255, 0.3);
}

.hero-images { 
    display: flex; 
    justify-content: center; 
    gap: 25px; 
    align-items: flex-end; 
    margin-top: 20px;
    z-index: 20;
}
.hero-images img { 
    max-width: 28%; 
    border: 1px solid var(--bp-accent);
    background: rgba(6, 35, 71, 0.8);
    padding: 5px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.5);
    transition: all 0.4s; 
    filter: sepia(0.3) hue-rotate(180deg) saturate(200%) brightness(0.8); /* Blueprint tint effect */
}
.hero-images img:hover { 
    transform: translateY(-10px); 
    filter: none; /* Remove tint on hover */
    border-color: var(--bp-white);
}

/* Features Section */
.features { padding: 100px 5%; position: relative; z-index: 10; background: rgba(6, 35, 71, 0.9); border-top: 1px solid var(--border-color); border-bottom: 1px solid var(--border-color);}
.section-title { 
    text-align: center; 
    font-size: 32px; 
    margin-bottom: 60px; 
    font-weight: bold;
    color: var(--bp-white);
    letter-spacing: 2px;
    text-transform: uppercase;
}
.section-title::before { content: '[ '; color: var(--bp-accent); }
.section-title::after { content: ' ]'; color: var(--bp-accent); }

.features-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 30px; max-width: 1200px; margin: 0 auto; }

.feature-card { 
    padding: 40px 30px; 
    background: rgba(11, 59, 115, 0.5);
    border: 1px solid var(--border-color);
    transition: all 0.3s; 
    position: relative;
}
/* Blueprint measurement lines on cards */
.feature-card::before {
    content: ''; position: absolute; top: 10px; left: 10px; width: 20px; height: 20px;
    border-top: 1px solid var(--bp-accent); border-left: 1px solid var(--bp-accent); opacity: 0.5;
}
.feature-card::after {
    content: ''; position: absolute; bottom: 10px; right: 10px; width: 20px; height: 20px;
    border-bottom: 1px solid var(--bp-accent); border-right: 1px solid var(--bp-accent); opacity: 0.5;
}
.feature-card:hover { 
    transform: translateY(-5px); 
    border-color: var(--bp-accent);
    background: rgba(11, 59, 115, 0.8);
    box-shadow: 0 5px 20px rgba(0, 255, 255, 0.1);
}
.feature-card h3 { 
    font-size: 20px; 
    margin-bottom: 15px; 
    color: var(--bp-accent);
    font-weight: normal;
}
.feature-card p { color: var(--text-muted); font-size: 14px; }

/* Blog Section */
.blog { padding: 100px 5%; }
.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: rgba(6, 35, 71, 0.8);
    border: 1px solid var(--border-color);
    transition: all 0.3s;
}
.blog-card:hover { 
    border-color: var(--bp-accent);
    box-shadow: 0 5px 20px rgba(0, 255, 255, 0.1);
}
.blog-card img { 
    width: 100%; height: 260px; object-fit: cover; 
    border-bottom: 1px solid var(--border-color);
    filter: grayscale(100%) contrast(1.2) brightness(0.8);
}
.blog-card:hover img { filter: none; }
.blog-content { padding: 30px; }
.blog-date { display: inline-block; margin-bottom: 15px; font-size: 12px; color: var(--bp-dark); background: var(--bp-accent); padding: 3px 10px; font-weight: bold;}
.blog-content h3 { font-size: 22px; margin-bottom: 15px; color: var(--bp-white);}
.blog-content p { color: var(--text-muted); margin-bottom: 0; font-size: 14px;}
.btn-more { 
    display: block; 
    width: 240px; 
    margin: 60px auto 0; 
    text-align: center; 
    padding: 14px; 
    background: transparent;
    color: var(--bp-accent); 
    font-weight: bold; 
    border: 1px solid var(--bp-accent);
    transition: all 0.3s; 
    text-transform: uppercase;
}
.btn-more:hover { background: rgba(0, 255, 255, 0.1); box-shadow: inset 0 0 10px rgba(0, 255, 255, 0.3);}

/* FAQ Section */
.faq { padding: 100px 5%; max-width: 900px; margin: 0 auto; background: rgba(6, 35, 71, 0.9); margin-top: 40px; margin-bottom: 80px; border: 1px solid var(--border-color);}
.faq-item { 
    background: transparent; 
    margin-bottom: 20px; 
    padding: 20px 0; 
    border-bottom: 1px dashed var(--border-color);
}
.faq-item:last-child { border-bottom: none; margin-bottom: 0; padding-bottom: 0; }
.faq-question { font-size: 18px; font-weight: bold; margin-bottom: 12px; color: var(--bp-accent);}
.faq-question::before { content: 'Q: '; opacity: 0.5; }
.faq-answer { color: var(--text-muted); font-size: 14px;}
.faq-answer::before { content: 'A: '; opacity: 0.5; color: var(--bp-white); }

/* Footer */
.footer { background: var(--bp-dark); padding: 60px 5% 30px; color: var(--text-muted); border-top: 2px solid var(--bp-accent); }
.footer-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 40px; max-width: 1200px; margin: 0 auto 50px; }
.footer-col h4 { font-size: 16px; color: var(--bp-white); margin-bottom: 25px; text-transform: uppercase; letter-spacing: 1px;}
.footer-col ul li { margin-bottom: 12px; font-size: 14px;}
.footer-col ul li a { color: var(--text-muted); transition: all 0.2s; }
.footer-col ul li a:hover { color: var(--bp-accent); text-decoration: underline;}
.footer-bottom { text-align: center; padding-top: 30px; border-top: 1px solid rgba(255,255,255,0.1); font-size: 12px; font-family: 'Courier New', monospace;}

/* 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: rgba(6, 35, 71, 0.8); 
    border: 1px solid var(--border-color);
    transition: all 0.3s;
}
.download-card:hover { 
    border-color: var(--bp-accent);
    box-shadow: 0 5px 20px rgba(0, 255, 255, 0.1);
}
.download-card h3 { font-size: 22px; margin-bottom: 15px; color: var(--bp-white);}
.download-card p { color: var(--text-muted); margin-bottom: 30px; font-size: 14px;}
.btn-dl-card { 
    display: inline-block; 
    padding: 12px 25px; 
    background: var(--bp-accent);
    color: var(--bp-dark); 
    font-weight: bold; 
    transition: all 0.2s; 
    text-transform: uppercase;
}
.btn-dl-card:hover { 
    background: var(--bp-white); 
    box-shadow: 0 0 15px rgba(255, 255, 255, 0.5);
}

/* Page specific headers */
.page-header { 
    padding: 80px 5% 60px; 
    text-align: center; 
    border-bottom: 1px solid var(--border-color);
    background: rgba(6, 35, 71, 0.5);
}
.page-header-content {
    max-width: 800px;
    margin: 0 auto;
}
.page-header h1 { 
    font-size: 36px; 
    margin-bottom: 20px; 
    color: var(--bp-white);
    letter-spacing: 2px;
}
.page-header p { font-size: 16px; color: var(--bp-accent); font-family: 'Courier New', monospace;}

/* === 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;
    }
}