/* ========== Reset & Base ========== */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
	font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
	color: #1a1a2e;
	background: #fff;
	line-height: 1.6;
	-webkit-font-smoothing: antialiased;
}
a { text-decoration: none; color: inherit; }
img, video { max-width: 100%; display: block; }
.container { max-width: 1200px; margin: 0 auto; padding: 0 24px; }

/* ========== Header ========== */
.site-header {
	position: fixed; top: 0; left: 0; right: 0; z-index: 1000;
	background: rgba(255,255,255,0.95);
	backdrop-filter: blur(10px);
	border-bottom: 1px solid rgba(0,0,0,0.06);
	transition: all .3s ease;
}
.header-inner {
	display: flex; align-items: center; justify-content: space-between;
	height: 72px;
}
.logo { display: flex; align-items: center; gap: 12px; }
.logo img { width: 40px; height: auto; }
.logo-text { display: flex; flex-direction: column; line-height: 1.2; }
.logo-cn { font-size: 16px; font-weight: 700; color: #1a1a2e; }
.logo-en { font-size: 11px; color: #666; letter-spacing: 1px; }

.main-nav { display: flex; gap: 32px; }
.main-nav a {
	font-size: 14px; color: #333; font-weight: 500;
	transition: color .2s;
}
.main-nav a:hover { color: #0078d4; }

.lang-switch {
	display: flex; gap: 8px; align-items: center;
	font-size: 13px;
}
.lang-switch a { margin:0 0 0 10px; padding: 4px 10px; border-radius: 4px; }
.lang-switch a.active { background: #0078d4; color: #fff; }
.main-nav a:hover, .main-nav a.active { color: #0078d4; }

/* ========== Hero ========== */
.hero {
	position: relative;
	min-height: 100vh;
	display: flex; align-items: center;
	background: linear-gradient(135deg, #0a1628 0%, #0f2847 40%, #143a6b 100%);
	overflow: hidden;
	padding-top: 72px;
}
.hero-video {
	position: absolute; top: 0; left: 0; width: 100%; height: 100%;
	object-fit: cover; opacity: .35; z-index: 0;
}
.hero-content {
	position: relative; z-index: 1;
	color: #fff;
	max-width: 800px;
}
.hero-badge {
	display: inline-block;
	padding: 6px 16px;
	background: rgba(0,120,212,0.2);
	border: 1px solid rgba(0,120,212,0.5);
	border-radius: 20px;
	font-size: 13px;
	letter-spacing: 1px;
	margin-bottom: 24px;
}
.hero h1 {
	font-size: clamp(32px, 5vw, 56px);
	font-weight: 800;
	line-height: 1.15;
	margin-bottom: 24px;
	letter-spacing: -0.5px;
}
.hero h1 .accent { color: #4fc3f7; }
.hero p.lead {
	font-size: clamp(16px, 2vw, 20px);
	color: rgba(255,255,255,0.85);
	margin-bottom: 40px;
	max-width: 640px;
}
.hero-cta { display: flex; gap: 16px; flex-wrap: wrap; }
.btn {
	display: inline-flex; align-items: center; justify-content: center;
	padding: 14px 32px;
	font-size: 15px; font-weight: 600;
	border-radius: 6px;
	transition: all .25s;
	cursor: pointer;
	border: none;
}
.btn-primary { background: #0078d4; color: #fff; }
.btn-primary:hover { background: #0060aa; transform: translateY(-2px); box-shadow: 0 8px 24px rgba(0,120,212,0.4); }
.btn-outline { background: transparent; color: #fff; border: 2px solid rgba(255,255,255,0.5); }
.btn-outline:hover { border-color: #fff; background: rgba(255,255,255,0.1); }

.hero-scroll {
	position: absolute; bottom: 32px; left: 50%; transform: translateX(-50%);
	z-index: 1; color: rgba(255,255,255,0.6); font-size: 13px;
	animation: bounce 2s infinite;
}
@keyframes bounce {
	0%, 100% { transform: translateX(-50%) translateY(0); }
	50% { transform: translateX(-50%) translateY(10px); }
}

/* ========== Section Common ========== */
section { padding: 96px 0; }
.section-header { text-align: center; margin-bottom: 64px; }
.section-header h2 {
	font-size: clamp(28px, 4vw, 40px);
	font-weight: 800;
	color: #1a1a2e;
	margin-bottom: 16px;
}
.section-header p {
	font-size: 17px;
	color: #666;
	max-width: 680px;
	margin: 0 auto;
}
.section-tag {
	display: inline-block;
	font-size: 13px;
	color: #0078d4;
	font-weight: 600;
	letter-spacing: 2px;
	text-transform: uppercase;
	margin-bottom: 12px;
}

/* ========== Products ========== */
.products { background: #f8fafc; }
.product-grid {
	display: grid;
	grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
	gap: 28px;
}
.product-card {
	background: #fff;
	border-radius: 12px;
	padding: 36px 28px;
	box-shadow: 0 2px 12px rgba(0,0,0,0.04);
	transition: all .3s;
	border-top: 4px solid transparent;
}
.product-card:hover {
	transform: translateY(-6px);
	box-shadow: 0 16px 40px rgba(0,0,0,0.1);
}
.product-card.x { border-top-color: #0078d4; }
.product-card.s { border-top-color: #00bcd4; }
.product-card.t { border-top-color: #1976d2; }
.product-card.z { border-top-color: #7c4dff; }

.product-card .icon {
	width: 56px; height: 56px;
	border-radius: 12px;
	display: flex; align-items: center; justify-content: center;
	font-size: 24px; font-weight: 800; color: #fff;
	margin-bottom: 20px;
}
.product-card.x .icon { background: #0078d4; }
.product-card.s .icon { background: #00bcd4; }
.product-card.t .icon { background: #1976d2; }
.product-card.z .icon { background: #7c4dff; }

.product-card h3 {
	font-size: 20px; font-weight: 700; margin-bottom: 8px; color: #1a1a2e;
}
.product-card .depth {
	font-size: 13px; color: #0078d4; font-weight: 600;
	margin-bottom: 16px;
}
.product-card p {
	font-size: 14px; color: #555; line-height: 1.7;
}
.product-card ul {
	list-style: none; padding: 0; margin-top: 16px;
}
.product-card ul li {
	font-size: 13px; color: #666; padding: 4px 0;
	padding-left: 18px; position: relative;
}
.product-card ul li::before {
	content: "✓"; position: absolute; left: 0; color: #0078d4; font-weight: 700;
}

/* ========== Tech Stack ========== */
.tech { background: #fff; }
.tech-grid {
	display: grid;
	grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
	gap: 40px;
}
.tech-item {
	text-align: left;
	padding: 32px;
	border-radius: 12px;
	background: #f8fafc;
	transition: all .3s;
}
.tech-item:hover { background: #eef4ff; }
.tech-item .num {
	font-size: 14px; font-weight: 700; color: #0078d4;
	margin-bottom: 12px; letter-spacing: 1px;
}
.tech-item h3 {
	font-size: 20px; font-weight: 700; margin-bottom: 12px; color: #1a1a2e;
}
.tech-item p { font-size: 14px; color: #555; line-height: 1.7; }

/* ========== Use Cases ========== */
.usecases { background: linear-gradient(180deg, #0a1628 0%, #0f2847 100%); color: #fff; }
.usecases .section-header h2 { color: #fff; }
.usecases .section-header p { color: rgba(255,255,255,0.7); }
.case-grid {
	display: grid;
	grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
	gap: 28px;
}
.case-card {
	background: rgba(255,255,255,0.06);
	border: 1px solid rgba(255,255,255,0.1);
	border-radius: 12px;
	padding: 32px 28px;
	transition: all .3s;
}
.case-card:hover {
	background: rgba(255,255,255,0.1);
	transform: translateY(-4px);
}
.case-card .case-icon { font-size: 36px; margin-bottom: 16px; }
.case-card h3 { font-size: 18px; font-weight: 700; margin-bottom: 12px; }
.case-card p { font-size: 14px; color: rgba(255,255,255,0.7); line-height: 1.7; }

/* ========== CTA Section ========== */
.cta-section {
	background: #0078d4;
	color: #fff;
	text-align: center;
	padding: 80px 0;
}
.cta-section h2 {
	font-size: clamp(26px, 4vw, 36px);
	font-weight: 800;
	margin-bottom: 16px;
}
.cta-section p {
	font-size: 17px;
	color: rgba(255,255,255,0.85);
	margin-bottom: 32px;
	max-width: 580px;
	margin-left: auto; margin-right: auto;
}
.cta-section .btn-primary {
	background: #fff; color: #0078d4;
}
.cta-section .btn-primary:hover {
	background: #e8f4fd; box-shadow: 0 8px 24px rgba(255,255,255,0.3);
}

/* ========== Footer ========== */
.site-footer {
	background: #0a1628;
	color: rgba(255,255,255,0.6);
	padding: 56px 0 32px;
	font-size: 14px;
}
.footer-grid {
	display: grid;
	grid-template-columns: 2fr 1fr 1fr 1fr;
	gap: 40px;
	margin-bottom: 40px;
}
.footer-brand .logo-cn { color: #fff; font-size: 18px; }
.footer-brand .logo-en { color: rgba(255,255,255,0.5); }
.footer-brand p {
	margin-top: 16px;
	font-size: 13px;
	color: rgba(255,255,255,0.45);
	max-width: 360px;
	line-height: 1.7;
}
.footer-col h4 {
	color: #fff; font-size: 15px; font-weight: 600;
	margin-bottom: 16px;
}
.footer-col a {
	display: block;
	padding: 4px 0;
	color: rgba(255,255,255,0.5);
	transition: color .2s;
}
.footer-col a:hover { color: #4fc3f7; }
.footer-bottom {
	border-top: 1px solid rgba(255,255,255,0.08);
	padding-top: 24px;
	display: flex; justify-content: space-between; flex-wrap: wrap; gap: 12px;
	font-size: 12px;
	color: rgba(255,255,255,0.35);
}

/* ========== Responsive ========== */
@media (max-width: 768px) {
	.main-nav { display: none; }
	.hero { padding-top: 100px; }
	.hero h1 { font-size: 32px; }
	.footer-grid { grid-template-columns: 1fr 1fr; }
	section { padding: 64px 0; }
}
@media (max-width: 480px) {
	.footer-grid { grid-template-columns: 1fr; }
	.hero-cta { flex-direction: column; }
	.btn { width: 100%; }
}