:root {
    --bg-color: #ffffff;
    --text-main: #1d1d1f;
    --text-secondary: #86868b;
    --accent-blue: #0071e3;
    --accent-hover: #0077ed;
    --bg-secondary: #f5f5f7;
    --nav-height: 44px;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    color: var(--text-main);
    background: var(--bg-color);
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
}

/* Navigation */
nav {
    position: fixed;
    top: 0; width: 100%;
    height: var(--nav-height);
    background: rgba(255, 255, 255, 0.8);
    backdrop-filter: saturate(180%) blur(20px);
    z-index: 1000;
    border-bottom: 1px solid rgba(0,0,0,0.1);
}

.nav-content {
    max-width: 980px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 100%;
    padding: 0 20px;
}

.logo { font-weight: 600; font-size: 14px; letter-spacing: -0.01em; }
.version { color: var(--text-secondary); font-weight: 400; margin-left: 5px; font-size: 12px;}

.nav-links a {
    text-decoration: none;
    color: var(--text-secondary);
    font-size: 12px;
    margin-left: 24px;
    transition: color 0.2s;
}
.nav-links a:hover { color: var(--accent-blue); }

.download-btn {
    background: var(--accent-blue);
    color: white !important;
    padding: 4px 12px;
    border-radius: 12px;
}
.download-btn:hover { background: var(--accent-hover); }

/* Hero */
.hero {
    text-align: center;
    padding-top: 120px;
    padding-bottom: 60px;
    background: var(--bg-color);
}

.hero h1 {
    font-size: 56px;
    line-height: 1.07;
    font-weight: 700;
    letter-spacing: -0.005em;
    margin-bottom: 12px;
}

.subtitle {
    font-size: 24px;
    line-height: 1.2;
    font-weight: 400;
    color: var(--text-main);
    margin-bottom: 30px;
    max-width: 600px;
    margin-left: auto; margin-right: auto;
}

.cta-group { display: flex; flex-direction: column; align-items: center; gap: 10px; }

.primary-btn {
    background: var(--accent-blue);
    color: white;
    text-decoration: none;
    padding: 12px 24px;
    border-radius: 980px;
    font-size: 17px;
    font-weight: 400;
    transition: transform 0.2s;
}
.primary-btn:hover { transform: scale(1.02); }

.compatibility { font-size: 12px; color: var(--text-secondary); }

.hero-image-container { margin-top: 60px; }
.hero-img {
    max-width: 800px;
    width: 90%;
    border-radius: 12px;
    box-shadow: 0 20px 40px rgba(0,0,0,0.15);
}

/* Sections */
section { padding: 100px 20px; }
.dual-engine { background: var(--bg-secondary); text-align: center; }

.section-header h2 { font-size: 40px; font-weight: 700; margin-bottom: 15px; }
.section-header p { font-size: 21px; color: var(--text-secondary); margin-bottom: 60px; }

.grid-2 {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 40px;
    max-width: 980px;
    margin: 0 auto;
}

.card {
    background: white;
    padding: 40px;
    border-radius: 18px;
    text-align: left;
    box-shadow: 0 4px 12px rgba(0,0,0,0.05);
}
.card h3 { font-size: 24px; margin: 15px 0 10px; }
.card p { color: var(--text-secondary); margin-bottom: 30px; }
.card img { width: 100%; border-radius: 8px; border: 1px solid #eee; }
.card-icon { font-size: 12px; font-weight: 700; color: var(--accent-blue); text-transform: uppercase; }

/* Privacy/Settings */
.grid-split {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    max-width: 980px;
    margin: 0 auto;
    align-items: center;
}
.feature-list { list-style: none; margin-top: 20px; }
.feature-list li { font-size: 19px; margin-bottom: 10px; color: var(--text-secondary); }
.rounded-shadow { width: 100%; border-radius: 12px; box-shadow: 0 20px 40px rgba(0,0,0,0.1); }

/* History */
.history { background: var(--bg-secondary); text-align: center; }
.container { max-width: 980px; margin: 0 auto; }
.full-width-img { width: 100%; margin-top: 40px; border-radius: 12px; box-shadow: 0 20px 40px rgba(0,0,0,0.1); }

/* Footer */
footer { background: #f5f5f7; padding: 40px 0; border-top: 1px solid #d2d2d7; }
.footer-content {
    max-width: 980px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    font-size: 12px;
    color: var(--text-secondary);
    padding: 0 20px;
}
.footer-links a { color: var(--text-main); text-decoration: none; margin-left: 20px; }

@media (max-width: 768px) {
    .hero h1 { font-size: 40px; }
    .grid-2, .grid-split { grid-template-columns: 1fr; }
}