* { box-sizing: border-box; margin: 0; padding: 0; }
html, body { height: 100%; }
body { font-family: "Segoe UI","Microsoft YaHei","PingFang SC",sans-serif; background: #f4f7fb; color: #1f2a37; line-height: 1.65; }
a { color: #1f7ae0; text-decoration: none; }
a:hover { text-decoration: underline; }
.navbar { background: #fff; border-bottom: 1px solid #e5ebf3; padding: 14px 24px; display: flex; align-items: center; gap: 24px; position: sticky; top: 0; z-index: 10; }
.navbar .logo { display: flex; align-items: center; gap: 10px; font-weight: 700; font-size: 20px; color: #0b3d80; }
.navbar .logo img { width: 32px; height: 32px; border-radius: 6px; }
.navbar nav { display: flex; gap: 18px; margin-left: auto; flex-wrap: wrap; }
.navbar nav a { color: #334155; padding: 6px 10px; border-radius: 6px; }
.navbar nav a:hover { background: #f9fbfe; text-decoration: none; }
.navbar nav a span { font-weight: 700; }
.navbar nav a small { color: #64748b; margin-left: 4px; }
.hero { background: linear-gradient(rgba(8,28,68,.55), rgba(8,28,68,.55)), url('./BT-1.png') center/cover no-repeat; color: #fff; padding: 64px 24px; text-align: center; min-height: 360px; }
.hero h1 { font-size: 38px; margin-bottom: 14px; }
.hero .subtitle { font-size: 20px; font-weight: 700; opacity: .98; max-width: 760px; margin: 0 auto 14px; }
.hero .desc { font-size: 15px; opacity: .85; max-width: 820px; margin: 0 auto 24px; line-height: 1.8; }
.hero p { font-size: 18px; opacity: .92; max-width: 760px; margin: 0 auto 24px; }
.hero .btn { display: inline-block; background: #fff; color: #0b3d80; padding: 12px 28px; border-radius: 30px; font-weight: 700; }
.hero .btn:hover { text-decoration: none; transform: translateY(-1px); }
.container { max-width: 1100px; margin: 0 auto; padding: 40px 24px; }
.section { background: #fff; border-radius: 12px; padding: 28px; margin-bottom: 24px; box-shadow: 0 2px 10px rgba(15,42,80,.05); }
.section h2 { color: #0b3d80; margin-bottom: 14px; font-size: 24px; }
.section p, .section li { color: #334155; }
.section ul, .section ol { padding-left: 22px; }
.section ul li, .section ol li { margin-bottom: 6px; }
.download-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); gap: 18px; margin-top: 12px; }
.download-card { border: 1px solid #e5ebf3; border-radius: 10px; padding: 18px; background: #f9fbfe; }
.download-card h3 { color: #0b3d80; margin-bottom: 8px; }
.download-card .dl { display: inline-block; margin-top: 10px; background: #1f7ae0; color: #fff; padding: 10px 20px; border-radius: 6px; font-weight: 700; }
.download-card .dl:hover { background: #0b3d80; text-decoration: none; }
footer { text-align: center; padding: 28px 16px; color: #64748b; font-size: 14px; border-top: 1px solid #e5ebf3; background: #fff; margin-top: 40px; }
.grid-2 { display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); gap: 16px; }
.feature-card { background: #f9fbfe; border: 1px solid #e5ebf3; border-radius: 10px; padding: 18px; }
.feature-card h3 { color: #0b3d80; font-size: 18px; margin-bottom: 8px; }
.feature-card p, .feature-card ul li { color: #475569; font-size: 14px; }
.feature-card ul { margin-top: 8px; padding-left: 18px; }
.feature-card ul li { margin-bottom: 4px; }
.flow { display: grid; grid-template-columns: repeat(auto-fit, minmax(180px, 1fr)); gap: 12px; }
.flow-step { background: linear-gradient(135deg, #1f7ae0 0%, #0b3d80 100%); color: #fff; border-radius: 10px; padding: 16px; }
.flow-step .num { display: inline-block; width: 28px; height: 28px; line-height: 28px; border-radius: 50%; background: #fff; color: #0b3d80; text-align: center; font-weight: 700; margin-bottom: 8px; }
.flow-step h4 { font-size: 15px; margin-bottom: 6px; }
.flow-step p { font-size: 13px; opacity: .92; }
.stats { display: grid; grid-template-columns: repeat(auto-fit, minmax(180px, 1fr)); gap: 14px; }
.stat-card { background: #fff; border: 1px solid #e5ebf3; border-radius: 10px; padding: 18px; text-align: center; }
.stat-card .num { font-size: 32px; font-weight: 800; color: #0b3d80; }
.stat-card .label { color: #475569; font-size: 14px; margin-top: 4px; }
.faq details { background: #f9fbfe; border: 1px solid #e5ebf3; border-radius: 8px; padding: 12px 16px; margin-bottom: 10px; }
.faq details summary { cursor: pointer; font-weight: 700; color: #0b3d80; outline: none; }
.faq details[open] { background: #fff; }
.faq details p { color: #475569; margin-top: 8px; font-size: 14px; }
@media (max-width: 640px) { .hero h1 { font-size: 28px; } .hero p { font-size: 16px; } .navbar { flex-wrap: wrap; } .navbar nav { width: 100%; } }