:root {
    --bg-main: #F4F7F6;
    --white: #FFFFFF;
    --text-dark: #2C3E50;
    --text-gray: #7F8C8D;
    --flat-blue: #3498DB;
    --flat-green: #2ECC71;
    --flat-red: #E74C3C;
    --flat-yellow: #F1C40F;
    --flat-purple: #9B59B6;
    --border-color: #E2E6E7;
}

* { margin: 0; padding: 0; box-sizing: border-box; }
body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Microsoft YaHei", sans-serif;
    background-color: var(--bg-main);
    color: var(--text-dark);
    line-height: 1.6;
}

a { text-decoration: none; color: inherit; transition: 0.2s; }
img { max-width: 100%; display: block; border-radius: 8px; }

/* 扁平导航 */
.header {
    background-color: var(--white);
    border-bottom: 2px solid var(--border-color);
    position: sticky; top: 0; z-index: 1000;
}
.nav-wrap {
    max-width: 1200px; margin: 0 auto; display: flex; justify-content: space-between; align-items: center; padding: 15px 20px;
}
.logo { font-size: 22px; font-weight: bold; color: var(--text-dark); display: flex; align-items: center; gap: 10px; }
.logo-icon { width: 36px; height: 36px; border-radius: 8px; background: var(--flat-blue); display: inline-block; padding: 2px; }
.nav-links { display: flex; gap: 20px; }
.nav-links a { font-size: 15px; font-weight: bold; color: var(--text-gray); padding: 8px 16px; border-radius: 6px; }
.nav-links a:hover, .nav-links a.active { background-color: var(--flat-blue); color: var(--white); }

/* 扁平按钮 */
.btn {
    display: inline-flex; align-items: center; justify-content: center; padding: 14px 32px;
    border-radius: 8px; font-size: 16px; font-weight: bold; cursor: pointer; transition: 0.2s; border: none; outline: none;
}
.btn-primary { background-color: var(--flat-blue); color: var(--white); }
.btn-primary:hover { filter: brightness(1.1); transform: translateY(-2px); }
.btn-outline { background-color: var(--white); color: var(--flat-blue); border: 2px solid var(--flat-blue); }
.btn-outline:hover { background-color: var(--flat-blue); color: var(--white); }

/* 通用容器 */
.container { max-width: 1200px; margin: 0 auto; padding: 60px 20px; }
.sec-title { text-align: center; font-size: 32px; font-weight: bold; color: var(--text-dark); margin-bottom: 15px; }
.sec-subtitle { text-align: center; font-size: 16px; color: var(--text-gray); margin-bottom: 50px; }

/* 扁平卡片 */
.flat-card { background: var(--white); border-radius: 12px; border: 2px solid var(--border-color); padding: 30px; transition: 0.2s; }
.flat-card:hover { border-color: var(--flat-blue); transform: translateY(-5px); box-shadow: 0 10px 20px rgba(0,0,0,0.05); }

/* Hero区 */
.hero { text-align: center; padding: 80px 20px 60px; background-color: var(--white); border-bottom: 2px solid var(--border-color); }
.hero h1 { font-size: 48px; font-weight: 800; color: var(--text-dark); margin-bottom: 20px; }
.hero .subtitle { font-size: 20px; color: var(--flat-blue); font-weight: bold; margin-bottom: 40px; }
.hero-btns { display: flex; justify-content: center; gap: 20px; margin-bottom: 50px; }
.hero-visual { max-width: 900px; margin: 0 auto; border: 4px solid var(--border-color); border-radius: 12px; overflow: hidden; }

/* 核心卖点 - 图标组合 */
.feature-grid { display: grid; grid-template-columns: repeat(5, 1fr); gap: 20px; }
.f-box { text-align: center; }
.f-icon-wrap { width: 70px; height: 70px; margin: 0 auto 20px; border-radius: 16px; display: flex; align-items: center; justify-content: center; }
.f-box:nth-child(1) .f-icon-wrap { background-color: var(--flat-blue); }
.f-box:nth-child(2) .f-icon-wrap { background-color: var(--flat-green); }
.f-box:nth-child(3) .f-icon-wrap { background-color: var(--flat-red); }
.f-box:nth-child(4) .f-icon-wrap { background-color: var(--flat-purple); }
.f-box:nth-child(5) .f-icon-wrap { background-color: var(--flat-yellow); }
.f-box img { width: 40px; height: 40px; filter: brightness(0) invert(1); }
.f-box h3 { font-size: 16px; font-weight: bold; color: var(--text-dark); margin-bottom: 10px; }
.f-box p { font-size: 14px; color: var(--text-gray); }

/* 功能详情 */
.detail-item { display: flex; align-items: center; gap: 50px; margin-bottom: 60px; }
.detail-item:nth-child(even) { flex-direction: row-reverse; }
.d-text { flex: 1; }
.d-text h3 { font-size: 28px; font-weight: bold; color: var(--text-dark); margin-bottom: 20px; }
.d-text p { font-size: 16px; color: var(--text-gray); margin-bottom: 30px; line-height: 1.8; }
.d-data { display: inline-block; padding: 8px 16px; background-color: var(--bg-main); border-radius: 6px; font-weight: bold; color: var(--flat-blue); border: 2px solid var(--border-color); }
.d-visual { flex: 1; border: 4px solid var(--border-color); border-radius: 12px; background: var(--white); padding: 10px; }

/* 浏览器对比 */
.compare-box { background: var(--white); border-radius: 12px; border: 2px solid var(--border-color); overflow: hidden; }
.compare-table { width: 100%; border-collapse: collapse; text-align: left; }
.compare-table th, .compare-table td { padding: 20px; border-bottom: 2px solid var(--border-color); }
.compare-table th { background-color: var(--bg-main); font-weight: bold; color: var(--text-gray); text-transform: uppercase; }
.compare-table td { font-weight: bold; color: var(--text-dark); }
.compare-table .hl { color: var(--flat-blue); background-color: rgba(52, 152, 219, 0.05); }
.compare-table tr:last-child td { border-bottom: none; }

/* 数据背书 */
.data-sec { background-color: var(--text-dark); color: var(--white); padding: 60px 0; margin: 40px 0; }
.data-inner { max-width: 1000px; margin: 0 auto; display: flex; justify-content: space-around; align-items: center; text-align: center; }
.data-item h4 { font-size: 40px; font-weight: bold; margin-bottom: 10px; color: var(--flat-green); }
.data-item p { font-size: 16px; font-weight: bold; color: #BDC3C7; }
.data-icon { width: 80px; height: 80px; border-radius: 20px; background-color: var(--flat-blue); padding: 15px; }
.data-icon img { filter: brightness(0) invert(1); }

/* 下载版本区 */
.dl-wrap { display: grid; grid-template-columns: repeat(3, 1fr); gap: 30px; }
.dl-card { text-align: center; }
.dl-icon { width: 60px; height: 60px; margin: 0 auto 20px; border-radius: 16px; background-color: var(--bg-main); display: flex; align-items: center; justify-content: center; font-size: 24px; font-weight: bold; color: var(--flat-blue); border: 2px solid var(--border-color); }
.dl-card h3 { font-size: 22px; font-weight: bold; color: var(--text-dark); margin-bottom: 15px; }
.dl-card p { font-size: 14px; color: var(--text-gray); margin-bottom: 30px; height: 42px; }
.dl-card .btn { width: 100%; }

/* FAQ */
.faq-wrap { max-width: 900px; margin: 0 auto; }
.faq-item { margin-bottom: 20px; padding: 25px; border-left: 6px solid var(--flat-blue); }
.faq-item h4 { font-size: 18px; font-weight: bold; color: var(--text-dark); margin-bottom: 10px; }
.faq-item p { font-size: 15px; color: var(--text-gray); }

/* Footer */
.footer { background-color: var(--white); border-top: 2px solid var(--border-color); padding: 40px 20px; text-align: center; color: var(--text-gray); font-size: 14px; font-weight: bold; margin-top: 50px; }