/* ===== 变量与重置 ===== */
:root {
    --primary: #2AABEE;
    --primary-dark: #229ED9;
    --text: #222;
    --text-light: #707579;
    --bg: #FFFFFF;
    --bg-alt: #F4F7F9;
    --radius: 12px;
    --shadow: 0 4px 20px rgba(0,0,0,0.06);
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif; color: var(--text); background: var(--bg); line-height: 1.6; }
a { text-decoration: none; color: inherit; transition: color 0.2s; }
.container { max-width: 1100px; margin: 0 auto; padding: 0 24px; }

/* ===== 按钮系统 ===== */
.btn-primary {
    background: var(--primary); color: #fff; border: none; padding: 10px 24px;
    border-radius: 8px; font-size: 15px; font-weight: 600; cursor: pointer;
    transition: background 0.2s, transform 0.1s;
}
.btn-primary:hover { background: var(--primary-dark); }
.btn-primary:active { transform: scale(0.97); }
.btn-outline {
    background: transparent; color: var(--primary); border: 2px solid var(--primary);
    padding: 10px 24px; border-radius: 8px; font-size: 15px; font-weight: 600; cursor: pointer;
}
.btn-outline:hover { background: rgba(42,171,238,0.08); }
.btn-lg { padding: 14px 32px; font-size: 17px; }

/* ===== 导航栏 ===== */
.navbar {
    position: fixed; top: 0; left: 0; right: 0; z-index: 100;
    background: rgba(255,255,255,0.92); backdrop-filter: blur(12px);
    border-bottom: 1px solid rgba(0,0,0,0.06);
}
.nav-container { display: flex; align-items: center; justify-content: space-between; height: 64px; }
.logo { display: flex; align-items: center; gap: 10px; font-size: 20px; font-weight: 700; color: var(--text); }
.nav-links { display: flex; gap: 32px; }
.nav-links a { font-size: 15px; color: var(--text-light); font-weight: 500; }
.nav-links a:hover { color: var(--primary); }
.mobile-menu-btn { display: none; background: none; border: none; font-size: 24px; cursor: pointer; }

/* ===== 英雄区 ===== */
.hero { padding: 140px 0 80px; background: linear-gradient(180deg, #fff 0%, var(--bg-alt) 100%); }
.hero-content { display: grid; grid-template-columns: 1fr 1fr; gap: 60px; align-items: center; }
.hero-text h1 { font-size: 48px; line-height: 1.15; margin-bottom: 20px; letter-spacing: -0.5px; }
.highlight { color: var(--primary); }
.hero-text p { font-size: 18px; color: var(--text-light); margin-bottom: 32px; max-width: 480px; }
.cta-group { display: flex; gap: 16px; flex-wrap: wrap; }

/* 纯CSS手机模型 */
.phone-mockup {
    width: 280px; height: 560px; background: #1e1e1e; border-radius: 36px;
    border: 4px solid #333; position: relative; margin: 0 auto;
    box-shadow: 0 20px 60px rgba(42,171,238,0.15);
}
.phone-mockup .screen {
    position: absolute; top: 12px; left: 12px; right: 12px; bottom: 12px;
    background: linear-gradient(135deg, #e3f2fd 0%, #bbdefb 100%);
    border-radius: 28px; overflow: hidden;
}

/* ===== 特性区 ===== */
.features { padding: 100px 0; }
.section-title { text-align: center; font-size: 36px; margin-bottom: 16px; }
.section-subtitle { text-align: center; color: var(--text-light); font-size: 18px; margin-bottom: 60px; }
.feature-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 32px; margin-top: 48px; }
.feature-card {
    padding: 32px; border-radius: var(--radius); background: var(--bg-alt);
    transition: transform 0.2s, box-shadow 0.2s;
}
.feature-card:hover { transform: translateY(-4px); box-shadow: var(--shadow); }
.feature-card h3 { font-size: 20px; margin: 16px 0 8px; }
.feature-card p { font-size: 15px; color: var(--text-light); }

/* 纯CSS图标 */
.icon { width: 48px; height: 48px; border-radius: 12px; display: flex; align-items: center; justify-content: center; font-size: 24px; }
.icon.speed { background: #E3F2FD; color: var(--primary); }
.icon.speed::after { content: "⚡"; }
.icon.security { background: #E8F5E9; color: #4CAF50; }
.icon.security::after { content: "🔒"; }
.icon.cloud { background: #FFF3E0; color: #FF9800; }
.icon.cloud::after { content: "☁️"; }
.icon.groups { background: #F3E5F5; color: #9C27B0; }
.icon.groups::after { content: "👥"; }

/* ===== 客户端区 ===== */
.apps-section { padding: 100px 0; background: var(--bg-alt); }
.app-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(160px, 1fr)); gap: 16px; margin-top: 48px; }
.app-card {
    display: flex; align-items: center; justify-content: center; padding: 24px;
    background: #fff; border-radius: var(--radius); font-weight: 600; font-size: 16px;
    transition: all 0.2s; border: 1px solid transparent;
}
.app-card:hover { border-color: var(--primary); color: var(--primary); box-shadow: var(--shadow); }

/* ===== 页脚 ===== */
.footer { padding: 48px 0; border-top: 1px solid #eee; }
.footer-content { display: flex; justify-content: space-between; align-items: center; flex-wrap: wrap; gap: 16px; }
.footer-brand p { font-size: 13px; color: var(--text-light); }
.footer-links { display: flex; gap: 24px; }
.footer-links a { font-size: 14px; color: var(--text-light); }
.footer-links a:hover { color: var(--primary); }

/* ===== 响应式 ===== */
@media (max-width: 768px) {
    .nav-links { display: none; }
    .mobile-menu-btn { display: block; }
    .hero-content { grid-template-columns: 1fr; text-align: center; }
    .hero-text h1 { font-size: 32px; }
    .hero-text p { margin: 0 auto 32px; }
    .cta-group { justify-content: center; }
    .phone-mockup { width: 220px; height: 440px; margin-top: 40px; }
    .section-title { font-size: 28px; }
    .footer-content { flex-direction: column; text-align: center; }
}