:root {
    --key-bg: #f2f2f2;
    --key-text: #333333;
    --key-primary: #000000;
    --key-secondary: #007aff;
    --key-accent: #e5e5ea;
    --font-key: -apple-system, BlinkMacSystemFont, 'Helvetica Neue', Helvetica, Arial, sans-serif;
}

* { margin: 0; padding: 0; box-sizing: border-box; }
body {
    background-color: var(--key-bg); color: var(--key-text);
    font-family: var(--font-key);
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
}
a { text-decoration: none; color: inherit; }

.key-container { max-width: 1000px; margin: 0 auto; padding: 0 20px;}

/* Header */
.key-header {
    display: flex; justify-content: space-between; align-items: center;
    padding: 20px 0; border-bottom: 1px solid rgba(0,0,0,0.1);
    margin-bottom: 60px;
}
.key-brand {
    font-size: 24px; font-weight: 600; color: var(--key-primary);
    letter-spacing: -0.5px;
}
.key-nav { display: flex; gap: 30px; }
.key-nav a {
    font-size: 14px; color: #666; transition: color 0.2s;
}
.key-nav a:hover, .key-nav a.active { color: var(--key-primary); }

/* Hero */
.key-hero {
    text-align: center; margin-bottom: 80px; padding: 60px 0;
}
.key-hero h1 {
    font-size: 56px; font-weight: 700; letter-spacing: -1px;
    margin-bottom: 20px; color: var(--key-primary);
}
.key-hero p {
    font-size: 24px; color: #666; margin-bottom: 40px; font-weight: 400;
    max-width: 800px; margin-left: auto; margin-right: auto;
}
.btn-key {
    display: inline-block; padding: 15px 30px; font-size: 17px; font-weight: 600;
    color: #fff; background: var(--key-secondary); border-radius: 30px;
    transition: background 0.2s; margin: 0 10px;
}
.btn-key:hover { background: #0056b3; }
.btn-key-alt {
    display: inline-block; padding: 15px 30px; font-size: 17px; font-weight: 600;
    color: var(--key-secondary); background: transparent;
    transition: color 0.2s; margin: 0 10px;
}
.btn-key-alt:hover { color: #0056b3; text-decoration: underline; }
.hero-image {
    margin-top: 60px; height: 300px; background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
    border-radius: 20px; box-shadow: 0 20px 40px rgba(0,0,0,0.1);
    display: flex; align-items: center; justify-content: center;
}
.hero-image::after { content: 'Product Interface Preview'; color: #888; font-size: 14px;}

/* Stats */
.key-stats {
    display: flex; justify-content: space-around; margin-bottom: 100px;
}
.ks-item { text-align: center; }
.ks-val { font-size: 48px; font-weight: 700; color: var(--key-primary); letter-spacing: -1px; margin-bottom: 5px;}
.ks-lbl { font-size: 14px; color: #666; font-weight: 500;}

/* Grid */
.key-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 40px; margin-bottom: 100px;}
.kg-card {
    padding: 40px; background: #fff; border-radius: 20px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.05); text-align: center;
}
.kg-icon {
    font-size: 40px; margin-bottom: 20px; color: var(--key-primary);
}
.kg-card h3 { font-size: 24px; font-weight: 600; margin-bottom: 15px; color: var(--key-primary);}
.kg-card p { font-size: 16px; color: #666; line-height: 1.5;}

/* Nodes */
.key-nodes { margin-bottom: 100px; text-align: center;}
.key-nodes h2 { font-size: 36px; font-weight: 700; margin-bottom: 40px; color: var(--key-primary); letter-spacing: -0.5px;}
.node-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 20px;}
.n-key {
    padding: 20px; background: #fff; border-radius: 15px;
    font-size: 16px; font-weight: 600; color: var(--key-primary);
    box-shadow: 0 5px 15px rgba(0,0,0,0.05);
}
.n-key span { display: block; font-size: 14px; color: #888; font-weight: 400; margin-top: 5px;}

/* FAQ */
.key-faq { margin-bottom: 100px; max-width: 800px; margin-left: auto; margin-right: auto;}
.key-faq h2 { font-size: 36px; font-weight: 700; margin-bottom: 40px; text-align: center; color: var(--key-primary); letter-spacing: -0.5px;}
.faq-item { margin-bottom: 30px; border-bottom: 1px solid rgba(0,0,0,0.1); padding-bottom: 20px;}
.fq-q { font-size: 20px; font-weight: 600; color: var(--key-primary); margin-bottom: 10px;}
.fq-a { font-size: 16px; color: #666;}

footer { text-align: center; padding: 40px 0; border-top: 1px solid rgba(0,0,0,0.1); font-size: 12px; color: #888;}

@media (max-width: 768px) {
    .key-hero h1 { font-size: 40px; }
    .key-hero p { font-size: 18px; }
    .key-stats { flex-direction: column; gap: 40px; }
    .key-grid { grid-template-columns: 1fr; }
    .btn-key, .btn-key-alt { display: block; margin: 10px auto; width: 80%;}
}