:root {
    --dt-blue: #0089FF;
    --dt-dark: #171A1D;
    --dt-gray: #F5F7FA;
    --dt-text: #333;
    --dt-sub: #666;
}

body {
    margin: 0;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    color: var(--dt-text);
    background: #fff;
    line-height: 1.5;
}

a { text-decoration: none; color: inherit; transition: 0.2s; }

/* Header */
.dt-header {
    height: 72px;
    background: rgba(255,255,255,0.9);
    backdrop-filter: blur(10px);
    position: fixed;
    top: 0;
    width: 100%;
    z-index: 100;
    border-bottom: 1px solid #eee;
}

.header-inner {
    max-width: 1200px;
    margin: 0 auto;
    height: 100%;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 24px;
}

.left { display: flex; align-items: center; gap: 48px; }
.logo { height: 28px; }

.nav-links a {
    margin-right: 32px;
    font-size: 15px;
    color: var(--dt-text);
}

.nav-links a:hover, .nav-links a.active {
    color: var(--dt-blue);
    font-weight: 500;
}

.right { display: flex; align-items: center; gap: 20px; }

.login-link { font-size: 14px; }
.reg-btn {
    background: var(--dt-blue);
    color: #fff;
    padding: 8px 20px;
    border-radius: 4px;
    font-size: 14px;
}
.reg-btn:hover { background: #0070cc; }

/* Hero */
.hero-section {
    padding-top: 140px;
    padding-bottom: 80px;
    background: #F0F6FF;
    text-align: center;
    overflow: hidden;
}

.hero-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

.hero-content h1 {
    font-size: 56px;
    margin-bottom: 16px;
    color: var(--dt-dark);
}

.hero-content p {
    font-size: 20px;
    color: var(--dt-sub);
    margin-bottom: 40px;
}

.hero-btns {
    display: flex;
    justify-content: center;
    gap: 16px;
    margin-bottom: 60px;
}

.btn-primary {
    background: var(--dt-blue);
    color: #fff;
    padding: 14px 36px;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 500;
}

.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 4px 12px rgba(0,137,255,0.3); }

.btn-secondary {
    background: #fff;
    color: var(--dt-text);
    padding: 14px 36px;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 500;
}

.btn-secondary:hover { color: var(--dt-blue); }

/* Mockup */
.hero-image {
    display: flex;
    justify-content: center;
}

.mockup-window {
    width: 800px;
    height: 500px;
    background: #fff;
    border-radius: 12px;
    box-shadow: 0 20px 60px rgba(0,0,0,0.1);
    overflow: hidden;
    display: flex;
    flex-direction: column;
}

.mockup-header {
    height: 48px;
    background: #f9f9f9;
    border-bottom: 1px solid #eee;
    display: flex;
    align-items: center;
    padding: 0 16px;
    gap: 16px;
}

.dots { display: flex; gap: 6px; }
.dots span { width: 10px; height: 10px; border-radius: 50%; background: #ddd; }
.search-bar { width: 200px; height: 24px; background: #eee; border-radius: 4px; }

.mockup-body { flex: 1; display: flex; }
.sidebar { width: 64px; background: #2E3238; }
.chat-list { width: 240px; background: #f7f7f7; border-right: 1px solid #eee; padding: 10px; }
.list-item { height: 50px; background: #e0e0e0; margin-bottom: 8px; border-radius: 4px; }
.list-item.active { background: #d0d0d0; }
.chat-area { flex: 1; background: #f5f5f5; padding: 20px; display: flex; flex-direction: column; gap: 16px; }
.msg { height: 40px; width: 60%; background: #fff; border-radius: 8px; }
.msg.sent { align-self: flex-end; background: #95EC69; }
.msg.large { height: 80px; }

/* Features */
.features-section { padding: 100px 0; }
.container { max-width: 1200px; margin: 0 auto; padding: 0 24px; }

.section-header { text-align: center; margin-bottom: 60px; }
.section-header h2 { font-size: 36px; margin-bottom: 16px; }
.section-header p { font-size: 18px; color: var(--dt-sub); }

.feature-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    /* Removed fixed rows to allow expansion */
    gap: 24px;
}

.f-card {
    background: #F7F9FC;
    border-radius: 16px;
    padding: 32px;
    transition: 0.3s;
    cursor: pointer;
    border: 1px solid transparent;
}

.f-card:hover {
    background: #fff;
    box-shadow: 0 10px 30px rgba(0,0,0,0.08);
    transform: translateY(-5px);
}

.f-card.large {
    grid-column: span 2;
    grid-row: span 2;
    background: #E6F4FF;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 60px;
}

.large .card-text { max-width: 300px; }
.large h3 { font-size: 32px; margin-bottom: 16px; }
.large p { font-size: 16px; color: #666; margin-bottom: 32px; }
.large .link { color: var(--dt-blue); font-weight: 600; }

.ai-vis { font-size: 100px; animation: float 3s ease-in-out infinite; }
@keyframes float { 0%,100% {transform:translateY(0);} 50% {transform:translateY(-10px);} }

.icon-box { width: 48px; height: 48px; border-radius: 12px; display: flex; align-items: center; justify-content: center; font-size: 24px; margin-bottom: 20px; }
.blue { background: #E6F7FF; }
.green { background: #F6FFED; }
.purple { background: #F9F0FF; }
.orange { background: #FFF7E6; }

.f-card h3 { margin: 0 0 8px; font-size: 20px; }
.f-card p { margin: 0; color: #666; font-size: 14px; }

/* News Section */
.news-section { background: #fff; padding: 80px 0; }
.news-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 32px; }
.news-card { border-radius: 12px; overflow: hidden; box-shadow: 0 4px 12px rgba(0,0,0,0.05); transition: 0.3s; cursor: pointer; }
.news-card:hover { transform: translateY(-5px); box-shadow: 0 12px 24px rgba(0,0,0,0.1); }
.news-img { height: 200px; background: #eee; }
.img-1 { background: linear-gradient(135deg, #FF9A9E 0%, #FECFEF 99%, #FECFEF 100%); }
.img-2 { background: linear-gradient(120deg, #84fab0 0%, #8fd3f4 100%); }
.img-3 { background: linear-gradient(120deg, #a1c4fd 0%, #c2e9fb 100%); }
.news-body { padding: 24px; }
.news-body .tag { font-size: 12px; color: var(--dt-blue); background: #E6F7FF; padding: 2px 8px; border-radius: 4px; }
.news-body h4 { margin: 12px 0; font-size: 18px; }
.news-body p { color: #666; font-size: 14px; margin-bottom: 16px; }
.news-body .date { font-size: 12px; color: #999; }

/* Rotate Section */
.rotate-section { padding: 100px 0; background: #F0F2F5; overflow: hidden; }
.rotate-container { display: flex; align-items: center; justify-content: space-between; max-width: 1000px; margin: 0 auto; }
.rotate-text { width: 40%; }
.rotate-text h2 { font-size: 36px; margin-bottom: 16px; }
.rotate-text p { font-size: 18px; color: #666; margin-bottom: 32px; }
.rotate-controls button { padding: 10px 20px; margin-right: 10px; border: 1px solid #ccc; background: #fff; cursor: pointer; border-radius: 4px; }

.rotate-stage { perspective: 1000px; width: 400px; height: 300px; position: relative; }
.spinner { width: 100%; height: 100%; transform-style: preserve-3d; animation: spin 10s infinite linear; position: absolute; }
.face { position: absolute; width: 300px; height: 200px; left: 50px; top: 50px; background: #fff; border: 1px solid #eee; display: flex; align-items: center; justify-content: center; font-size: 24px; font-weight: bold; box-shadow: 0 10px 30px rgba(0,0,0,0.1); border-radius: 12px; opacity: 0.9; cursor: pointer; }
.f1 { transform: rotateY(0deg) translateZ(250px); }
.f2 { transform: rotateY(120deg) translateZ(250px); }
.f3 { transform: rotateY(240deg) translateZ(250px); }
@keyframes spin { from { transform: rotateY(0deg); } to { transform: rotateY(360deg); } }

/* Reviews */
.review-section { padding: 100px 0; background: #fff; }
.review-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.review-card { background: #FAFAFA; padding: 32px; border-radius: 16px; cursor: pointer; transition: 0.3s; }
.review-card:hover { background: #fff; box-shadow: 0 10px 30px rgba(0,0,0,0.08); }
.review-header { display: flex; align-items: center; gap: 16px; margin-bottom: 20px; }
.review-header .avatar { width: 48px; height: 48px; border-radius: 50%; background: #ddd; }
.av-1 { background: #FFD700; }
.av-2 { background: #FF6B6B; }
.av-3 { background: #4ECDC4; }
.review-header h4 { margin: 0; font-size: 16px; }
.review-header span { font-size: 12px; color: #666; }
.review-text { font-size: 14px; color: #333; line-height: 1.6; margin-bottom: 16px; font-style: italic; }
.stars { color: #FFD700; font-size: 14px; }

/* Solutions */
.solutions-section { padding: 80px 0; background: #fff; }

.sol-tabs {
    display: flex;
    justify-content: center;
    gap: 40px;
    margin-bottom: 40px;
    border-bottom: 1px solid #eee;
}

.tab {
    padding-bottom: 16px;
    font-size: 16px;
    color: #666;
    cursor: pointer;
    border-bottom: 2px solid transparent;
}

.tab.active { color: var(--dt-blue); border-bottom-color: var(--dt-blue); font-weight: 500; }

.sol-content {
    background: #F5F7FA;
    border-radius: 16px;
    display: flex;
    overflow: hidden;
    cursor: pointer;
}

.sol-text { flex: 1; padding: 60px; }
.sol-text h3 { font-size: 28px; margin-bottom: 16px; }
.sol-text p { font-size: 16px; color: #666; margin-bottom: 32px; }

.sol-list { list-style: none; padding: 0; margin-bottom: 40px; }
.sol-list li { margin-bottom: 12px; padding-left: 20px; position: relative; }
.sol-list li::before { content: '•'; color: var(--dt-blue); position: absolute; left: 0; font-weight: bold; }

.btn-outline {
    border: 1px solid var(--dt-text);
    padding: 10px 24px;
    border-radius: 4px;
    font-size: 14px;
    display: inline-block;
}

.sol-img { flex: 1; background: #E1E8F0; }

/* Footer */
.dt-footer {
    background: #171A1D;
    color: #fff;
    padding: 80px 0 20px;
}

.footer-top {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
    display: flex;
    justify-content: space-between;
    margin-bottom: 60px;
}

.col h4 { margin-bottom: 24px; font-size: 16px; }
.col a { display: block; color: #999; margin-bottom: 12px; font-size: 14px; }
.col a:hover { color: #fff; }

.footer-bottom {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px 24px 0;
    border-top: 1px solid #333;
    font-size: 12px;
    color: #666;
}

/* Animations */
.fade-in { opacity: 0; transform: translateY(20px); animation: fadeIn 0.8s forwards; }
.delay-1 { animation-delay: 0.2s; }
.delay-2 { animation-delay: 0.4s; }
.delay-3 { animation-delay: 0.6s; }
@keyframes fadeIn { to { opacity: 1; transform: translateY(0); } }

/* Modal */
.modal {
    display: none;
    position: fixed;
    z-index: 2000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background: rgba(0,0,0,0.6);
    backdrop-filter: blur(4px);
}

.modal-content {
    background: #fff;
    width: 640px;
    margin: 8% auto;
    border-radius: 12px;
    padding: 40px;
    position: relative;
}

.close-modal {
    position: absolute;
    right: 24px;
    top: 24px;
    font-size: 28px;
    cursor: pointer;
}