:root {
    --bg-sky: #E8F4F8; /* 浅蓝天空背景 */
    --bg-cloud: #FFFFFF;
    --cloud-blue: #3498DB; /* 云端蓝 */
    --cloud-blue-hover: #2980B9;
    --cloud-soft: #A3D5FF;
    --text-title: #2C3E50;
    --text-body: #5D6D7E;
    --text-light: #95A5A6;
    --border-cloud: rgba(255, 255, 255, 0.8);
    --shadow-cloud: 0 15px 35px rgba(52, 152, 219, 0.1);
    --shadow-hover: 0 20px 40px rgba(52, 152, 219, 0.2);
}

* { margin: 0; padding: 0; box-sizing: border-box; }
body { font-family: "PingFang SC", "Microsoft YaHei", sans-serif; background-color: var(--bg-sky); color: var(--text-body); line-height: 1.6; overflow-x: hidden; position: relative; }
a { text-decoration: none; color: inherit; transition: 0.3s; }
img { max-width: 100%; display: block; border-radius: 12px; }
ul { list-style: none; }

/* 云朵漂浮背景 */
.clouds-bg { position: fixed; top: 0; left: 0; width: 100%; height: 100%; z-index: -1; pointer-events: none; overflow: hidden; background: linear-gradient(180deg, #D4EDFA 0%, #F4FAFD 100%); }
.cloud-shape { position: absolute; background: #FFF; border-radius: 50%; filter: blur(20px); opacity: 0.6; animation: floatCloud linear infinite; }
.cloud-1 { width: 300px; height: 100px; top: 10%; left: -20%; animation-duration: 40s; }
.cloud-2 { width: 400px; height: 150px; top: 40%; right: -20%; animation-duration: 50s; animation-direction: reverse; }
.cloud-3 { width: 250px; height: 80px; bottom: 20%; left: 30%; animation-duration: 35s; }
@keyframes floatCloud { 0% { transform: translateX(0); } 100% { transform: translateX(120vw); } }

/* 导航 */
.header { background: rgba(255, 255, 255, 0.85); border-bottom: 1px solid #FFF; position: sticky; top: 0; z-index: 1000; backdrop-filter: blur(10px); box-shadow: 0 4px 20px rgba(0,0,0,0.03); }
.nav-wrap { max-width: 1200px; margin: 0 auto; display: flex; justify-content: space-between; align-items: center; height: 70px; padding: 0 20px; }
.logo { font-size: 22px; font-weight: 800; color: var(--text-title); display: flex; align-items: center; gap: 10px; letter-spacing: 1px; }
.logo img { width: 32px; height: 32px; filter: drop-shadow(0 4px 6px rgba(52, 152, 219, 0.3)); }
.logo span { color: var(--cloud-blue); }
.nav-links { display: flex; gap: 30px; }
.nav-links a { font-size: 15px; font-weight: 600; color: var(--text-body); padding: 8px 16px; border-radius: 20px; transition: 0.3s; }
.nav-links a:hover, .nav-links a.active { color: var(--cloud-blue); background: #EBF5FB; }

.container { max-width: 1200px; margin: 0 auto; padding: 80px 20px; position: relative; z-index: 2; }

/* 柔和云端按钮 */
.btn { display: inline-flex; align-items: center; justify-content: center; padding: 15px 36px; border-radius: 30px; font-size: 16px; font-weight: bold; cursor: pointer; transition: 0.4s; letter-spacing: 1px; box-shadow: 0 4px 15px rgba(0,0,0,0.05); }
.btn-primary { background: linear-gradient(135deg, #5DADE2, var(--cloud-blue)); color: #FFF; border: none; }
.btn-primary:hover { background: linear-gradient(135deg, var(--cloud-blue), #21618C); transform: translateY(-3px); box-shadow: 0 10px 20px rgba(52, 152, 219, 0.4); }
.btn-outline { background: var(--bg-cloud); color: var(--cloud-blue); border: 2px solid var(--cloud-blue); }
.btn-outline:hover { background: #EBF5FB; transform: translateY(-3px); box-shadow: 0 8px 15px rgba(52, 152, 219, 0.2); }

/* 首屏 Hero 区 */
.hero { display: flex; align-items: center; gap: 50px; padding: 100px 20px 120px; max-width: 1200px; margin: 0 auto; position: relative; z-index: 2; }
.hero-content { flex: 1.1; animation: slideUp 1s ease-out forwards; }
@keyframes slideUp { from { opacity: 0; transform: translateY(30px); } to { opacity: 1; transform: translateY(0); } }
.cloud-tag { display: inline-flex; align-items: center; gap: 8px; background: #FFF; border: 1px solid var(--cloud-soft); color: var(--cloud-blue); padding: 6px 16px; border-radius: 20px; font-size: 13px; font-weight: bold; margin-bottom: 20px; box-shadow: 0 2px 10px rgba(52, 152, 219, 0.1); }
.hero-content h1 { font-size: 52px; font-weight: 900; color: var(--text-title); margin-bottom: 16px; line-height: 1.2; letter-spacing: 1px; }
.hero-content .subtitle { font-size: 24px; color: var(--cloud-blue); font-weight: 600; margin-bottom: 24px; }
.hero-content .desc { font-size: 16px; color: var(--text-body); margin-bottom: 40px; line-height: 1.8; max-width: 500px; }
.hero-btns { display: flex; gap: 20px; }
/* 网页窗口悬浮动画 */
.hero-visual { flex: 1; position: relative; perspective: 1000px; }
.hero-visual img { border-radius: 16px; border: 8px solid #FFF; box-shadow: var(--shadow-cloud); animation: floatWindow 6s ease-in-out infinite; }
@keyframes floatWindow { 0%, 100% { transform: translateY(0) rotateX(5deg); } 50% { transform: translateY(-20px) rotateX(-2deg); } }

/* 模块标题 */
.sec-title { text-align: center; font-size: 34px; font-weight: 800; color: var(--text-title); margin-bottom: 60px; position: relative; }
.sec-title::after { content: '☁'; display: block; font-size: 24px; color: var(--cloud-soft); margin-top: 10px; }

/* 核心卖点 - 云端卡片 */
.feature-grid { display: grid; grid-template-columns: repeat(5, 1fr); gap: 20px; }
.f-box { background: rgba(255,255,255,0.7); backdrop-filter: blur(10px); padding: 35px 20px; text-align: center; border-radius: 20px; border: 1px solid #FFF; box-shadow: var(--shadow-cloud); transition: 0.4s; }
.f-box:hover { transform: translateY(-8px); background: #FFF; box-shadow: var(--shadow-hover); }
.f-box img { width: 50px; height: 50px; margin: 0 auto 15px; filter: drop-shadow(0 5px 10px rgba(52,152,219,0.2)); }
.f-box h3 { font-size: 17px; font-weight: bold; color: var(--text-title); margin-bottom: 8px; }
.f-box p { font-size: 13px; color: var(--text-body); }

/* 功能详情 */
.detail-box { display: flex; align-items: center; gap: 60px; margin-bottom: 80px; background: rgba(255,255,255,0.6); backdrop-filter: blur(8px); padding: 50px; border-radius: 24px; border: 2px solid #FFF; box-shadow: 0 10px 30px rgba(0,0,0,0.02); }
.detail-box:nth-child(even) { flex-direction: row-reverse; }
.d-text { flex: 1; }
.d-text h3 { font-size: 28px; font-weight: 800; color: var(--text-title); margin-bottom: 15px; }
.d-text p { font-size: 15px; color: var(--text-body); margin-bottom: 25px; line-height: 1.8; }
.d-data { display: inline-block; padding: 8px 20px; background: #FFF; color: var(--cloud-blue); font-weight: bold; border-radius: 20px; box-shadow: 0 4px 10px rgba(52,152,219,0.1); border: 1px solid var(--cloud-soft); }
.d-visual { flex: 1.2; position: relative; }
.d-visual img { border: 6px solid #FFF; box-shadow: var(--shadow-cloud); border-radius: 16px; }

/* 浏览器对比 */
.compare-box { background: #FFF; border-radius: 20px; padding: 40px; box-shadow: var(--shadow-cloud); border: 1px solid var(--cloud-soft); }
.compare-table { width: 100%; border-collapse: collapse; text-align: left; }
.compare-table th, .compare-table td { padding: 20px; border-bottom: 1px solid #F0F4F8; }
.compare-table th { color: var(--text-light); font-size: 14px; font-weight: 600; background: #F8FBFC; border-radius: 8px; }
.compare-table td { font-size: 15px; color: var(--text-title); font-weight: 500; }
.compare-table .hl { color: var(--cloud-blue); font-weight: bold; background: #F4FAFD; border-left: 3px solid var(--cloud-blue); border-radius: 4px; }
.compare-table tr:last-child td { border-bottom: none; }

/* 下载版本区 */
.dl-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 30px; }
.dl-card { background: rgba(255,255,255,0.8); backdrop-filter: blur(5px); border: 2px solid #FFF; padding: 45px 30px; text-align: center; border-radius: 24px; transition: 0.4s; box-shadow: var(--shadow-cloud); }
.dl-card:hover { transform: translateY(-10px); background: #FFF; box-shadow: var(--shadow-hover); border-color: var(--cloud-soft); }
.dl-card.rec { border-color: var(--cloud-blue); position: relative; }
.dl-card.rec::before { content: '云端同步推荐'; position: absolute; top: -14px; left: 50%; transform: translateX(-50%); background: var(--cloud-blue); color: #FFF; padding: 4px 16px; font-size: 12px; font-weight: bold; border-radius: 20px; box-shadow: 0 4px 10px rgba(52,152,219,0.3); }
.dl-card h3 { font-size: 22px; font-weight: 800; color: var(--text-title); margin-bottom: 15px; }
.dl-card p { font-size: 14px; color: var(--text-body); margin-bottom: 30px; height: 42px; }
.dl-card .btn { width: 100%; }

/* 数据背书 */
.data-sec { background: linear-gradient(135deg, #E0F2FA, #C2E4F6); padding: 80px 20px; margin: 80px 0; border-top: 2px solid #FFF; border-bottom: 2px solid #FFF; }
.data-inner { max-width: 1000px; margin: 0 auto; display: flex; justify-content: space-around; }
.data-item { text-align: center; background: rgba(255,255,255,0.5); padding: 30px; border-radius: 20px; backdrop-filter: blur(5px); box-shadow: 0 10px 20px rgba(0,0,0,0.02); }
.data-item h4 { font-size: 48px; font-weight: 900; color: var(--cloud-blue); margin-bottom: 5px; }
.data-item p { font-size: 15px; font-weight: bold; color: var(--text-title); letter-spacing: 1px; }

/* FAQ */
.faq-grid { max-width: 800px; margin: 0 auto; display: flex; flex-direction: column; gap: 15px; }
.faq-box { background: #FFF; padding: 25px 30px; border-radius: 16px; box-shadow: 0 5px 15px rgba(0,0,0,0.02); border: 1px solid #FFF; transition: 0.3s; }
.faq-box:hover { border-color: var(--cloud-soft); box-shadow: 0 8px 20px rgba(52,152,219,0.08); }
.faq-box h4 { font-size: 16px; font-weight: bold; color: var(--text-title); margin-bottom: 10px; display: flex; align-items: center; gap: 10px; }
.faq-box h4::before { content: '☁'; color: var(--cloud-blue); font-size: 18px; }
.faq-box p { font-size: 14px; color: var(--text-body); line-height: 1.7; padding-left: 28px; }

/* Footer */
.footer { background: #FFFFFF; text-align: center; padding: 50px 20px; color: var(--text-light); font-size: 14px; margin-top: 80px; box-shadow: 0 -4px 20px rgba(0,0,0,0.02); }