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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #f8faff;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

header {
    height: 70px;
    display: flex;
    align-items: center;
    background: #fff;
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: 0 2px 10px rgba(0,0,0,0.02);
}

header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    width: 100%;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-weight: bold;
    font-size: 18px;
}

.logo img {
    height: 30px;
}

nav a {
    margin: 0 15px;
    text-decoration: none;
    color: #666;
    font-size: 14px;
}

.btn-download-top {
    text-decoration: none;
    color: #333;
    font-size: 14px;
}

.hero {
    padding: 100px 0;
    text-align: center;
}

.hero h1 {
    font-size: 48px;
    margin-bottom: 20px;
    color: #1a1a1a;
}

.hero p {
    font-size: 18px;
    color: #666;
    margin-bottom: 40px;
}

.hero-btns {
    display: flex;
    justify-content: center;
    gap: 20px;
    margin-bottom: 60px;
}

.btn-primary {
    background-color: #3b71fe;
    color: #fff;
    padding: 12px 40px;
    border-radius: 6px;
    text-decoration: none;
    font-weight: 500;
    box-shadow: 0 4px 14px rgba(59, 113, 254, 0.3);
}

.btn-secondary {
    background-color: #fff;
    color: #333;
    padding: 12px 40px;
    border-radius: 6px;
    text-decoration: none;
    border: 1px solid #ddd;
}

.hero-image img {
    max-width: 1000px;
    width: 100%;
    height: auto;
    border-radius: 12px;
    box-shadow: 0 30px 60px rgba(0,0,0,0.08);
}

.features {
    padding: 80px 0;
    background: #fff;
}

.feature-tabs {
    display: flex;
    justify-content: center;
    gap: 30px;
    margin-bottom: 50px;
    border-bottom: 1px solid #eee;
    padding-bottom: 15px;
}

.feature-tabs span {
    cursor: pointer;
    color: #666;
    font-size: 16px;
    position: relative;
}

.feature-tabs span.active {
    color: #3b71fe;
    font-weight: bold;
}

.feature-tabs span.active::after {
    content: '';
    position: absolute;
    bottom: -16px;
    left: 0;
    width: 100%;
    height: 3px;
    background: #3b71fe;
}

.feature-content {
    text-align: center;
    max-width: 800px;
    margin: 0 auto;
}

.feature-item h2 {
    font-size: 32px;
    margin-bottom: 20px;
}

.feature-item p {
    font-size: 16px;
    color: #666;
    margin-bottom: 30px;
}

.btn-link {
    color: #3b71fe;
    text-decoration: none;
    font-weight: 500;
}

.security {
    padding: 80px 0;
}

.security-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 40px;
}

.security-item {
    background: #fff;
    padding: 40px;
    border-radius: 12px;
    box-shadow: 0 4px 20px rgba(0,0,0,0.03);
}

.security-item h3 {
    margin-bottom: 15px;
    font-size: 22px;
}

.security-item p {
    color: #666;
    font-size: 15px;
}

footer {
    padding: 60px 0;
    background: #f8faff;
    text-align: center;
    border-top: 1px solid #eee;
}

.footer-links {
    margin-top: 20px;
}

.footer-links a {
    margin: 0 10px;
    color: #999;
    text-decoration: none;
    font-size: 13px;
}