:root {
    --dt3-primary: #0089FF;
    --dt3-secondary: #0056B3;
    --dt3-text: #171A1D;
    --dt3-gray: #F5F7FA;
    --dt3-border: #E5E7EB;
}

body {
    margin: 0;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'PingFang SC', sans-serif;
    color: var(--dt3-text);
    background: #fff;
    overflow-x: hidden;
}

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

/* Header */
.official-header {
    height: 72px;
    position: fixed;
    top: 0;
    width: 100%;
    background: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid rgba(0,0,0,0.05);
    z-index: 1000;
}

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

.logo {
    height: 28px;
    display: block;
}

.main-menu {
    display: flex;
    gap: 32px;
}

.main-menu a {
    font-size: 15px;
    color: #4B5563;
    font-weight: 500;
}

.main-menu a:hover, .main-menu a.active {
    color: var(--dt3-primary);
}

.user-actions {
    display: flex;
    align-items: center;
    gap: 16px;
}

.btn-login {
    font-size: 14px;
    color: #4B5563;
}

.btn-register {
    background: var(--dt3-primary);
    color: #fff;
    padding: 8px 20px;
    border-radius: 6px;
    font-size: 14px;
    font-weight: 600;
}

.btn-register:hover {
    background: var(--dt3-secondary);
}

/* Hero Section */
.hero-section {
    padding-top: 140px;
    padding-bottom: 80px;
    text-align: center;
    background: radial-gradient(circle at 50% 10%, #F0F9FF 0%, #FFFFFF 70%);
    overflow: hidden;
}

.hero-text h1 {
    font-size: 64px;
    font-weight: 800;
    margin-bottom: 16px;
    letter-spacing: -2px;
    background: linear-gradient(135deg, #171A1D 0%, #4B5563 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.hero-text p {
    font-size: 20px;
    color: #6B7280;
    margin-bottom: 40px;
}

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

.btn-primary {
    background: var(--dt3-primary);
    color: #fff;
    padding: 14px 32px;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 600;
    box-shadow: 0 4px 12px rgba(0, 137, 255, 0.3);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 20px rgba(0, 137, 255, 0.4);
}

.btn-outline {
    border: 1px solid var(--dt3-border);
    background: #fff;
    color: var(--dt3-text);
    padding: 14px 32px;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 600;
}

.btn-outline:hover {
    border-color: var(--dt3-primary);
    color: var(--dt3-primary);
}

/* Hero Visual Mockup */
.hero-visual {
    display: flex;
    justify-content: center;
    perspective: 1000px;
}

.app-screenshot-mockup {
    width: 900px;
    height: 560px;
    background: #fff;
    border-radius: 16px;
    box-shadow: 0 20px 60px rgba(0,0,0,0.1);
    border: 1px solid rgba(0,0,0,0.05);
    overflow: hidden;
    display: flex;
    flex-direction: column;
    transform: rotateX(5deg);
    transition: transform 0.5s ease;
}

.app-screenshot-mockup:hover {
    transform: rotateX(0deg) scale(1.02);
}

.window-header {
    height: 48px;
    background: #F3F4F6;
    border-bottom: 1px solid #E5E7EB;
    display: flex;
    align-items: center;
    padding: 0 16px;
    justify-content: space-between;
}

.traffic-lights {
    display: flex;
    gap: 8px;
}

.traffic-lights span {
    width: 12px;
    height: 12px;
    border-radius: 50%;
    background: #E5E7EB;
}

.traffic-lights span:nth-child(1) { background: #FF5F57; }
.traffic-lights span:nth-child(2) { background: #FFBD2E; }
.traffic-lights span:nth-child(3) { background: #28C840; }

.search-box {
    background: #fff;
    padding: 6px 12px;
    border-radius: 4px;
    font-size: 12px;
    color: #9CA3AF;
    width: 200px;
    border: 1px solid #E5E7EB;
}

.window-body {
    flex: 1;
    display: flex;
    background: #fff;
}

.sidebar {
    width: 64px;
    background: #1F2937;
    display: flex;
    flex-direction: column;
    align-items: center;
    padding-top: 20px;
    gap: 24px;
}

.icon {
    font-size: 24px;
    color: #9CA3AF;
    cursor: pointer;
}

.icon.active {
    color: #fff;
}

.list-panel {
    width: 240px;
    background: #F9FAFB;
    border-right: 1px solid #E5E7EB;
    display: flex;
    flex-direction: column;
}

.list-item {
    padding: 12px 16px;
    display: flex;
    align-items: center;
    gap: 12px;
    cursor: pointer;
}

.list-item.active {
    background: #E5E7EB;
}

.avatar {
    width: 40px;
    height: 40px;
    border-radius: 8px;
    background: #0089FF;
    color: #fff;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 14px;
    font-weight: bold;
}

.avatar.group {
    background: #10B981;
}

.info .name {
    font-size: 14px;
    font-weight: 600;
    color: #374151;
}

.info .text {
    font-size: 12px;
    color: #9CA3AF;
}

.chat-panel {
    flex: 1;
    display: flex;
    flex-direction: column;
    background: #fff;
}

.chat-header-bar {
    height: 56px;
    border-bottom: 1px solid #E5E7EB;
    display: flex;
    align-items: center;
    padding: 0 24px;
    font-weight: 600;
}

.chat-messages {
    flex: 1;
    padding: 24px;
    background: #F3F4F6;
}

.msg {
    display: flex;
    gap: 12px;
}

.msg-bubble {
    background: #fff;
    padding: 16px;
    border-radius: 0 12px 12px 12px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.05);
    max-width: 80%;
}

.msg-bubble h4 {
    margin: 0 0 8px 0;
    color: #0089FF;
}

.msg-bubble p {
    margin: 4px 0;
    font-size: 13px;
    color: #4B5563;
}

/* Bento Grid */
.value-section {
    padding: 100px 0;
    background: #fff;
}

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

.section-title {
    text-align: center;
    margin-bottom: 60px;
}

.section-title h2 {
    font-size: 40px;
    margin-bottom: 16px;
}

.bento-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    grid-template-rows: repeat(2, 280px);
    gap: 24px;
}

.bento-card {
    background: #F9FAFB;
    border-radius: 24px;
    padding: 40px;
    position: relative;
    overflow: hidden;
    transition: all 0.3s;
    border: 1px solid transparent;
    cursor: pointer;
}

.bento-card:hover {
    background: #fff;
    box-shadow: 0 20px 40px rgba(0,0,0,0.08);
    border-color: #E5E7EB;
    transform: translateY(-5px);
}

.large {
    grid-column: span 2;
    grid-row: span 2;
    background: linear-gradient(135deg, #E6F7FF 0%, #FFFFFF 100%);
}

.card-text {
    position: relative;
    z-index: 2;
}

.card-text h3 {
    font-size: 32px;
    margin-bottom: 16px;
}

.card-text p {
    font-size: 18px;
    color: #6B7280;
    line-height: 1.6;
    max-width: 400px;
}

.link-arrow {
    display: inline-block;
    margin-top: 24px;
    color: var(--dt3-primary);
    font-weight: 600;
    font-size: 16px;
}

.card-visual {
    position: absolute;
    bottom: 0;
    right: 0;
    width: 300px;
    height: 300px;
}

.ai-visual {
    background: url('https://gw.alicdn.com/imgextra/i2/O1CN01...mockup.png') no-repeat center;
    background-size: contain;
    /* Placeholder visual using CSS */
    display: flex;
    align-items: center;
    justify-content: center;
}

.floating-icon {
    font-size: 120px;
    animation: float 4s ease-in-out infinite;
}

.medium h3 {
    font-size: 24px;
}

.medium p {
    font-size: 14px;
}

/* Matrix Section */
.matrix-section {
    padding: 80px 0;
    background: #FAFAFA;
}

.matrix-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 24px;
}

.matrix-item {
    background: #fff;
    padding: 32px;
    border-radius: 16px;
    border: 1px solid #E5E7EB;
    transition: all 0.3s;
    cursor: pointer;
}

.matrix-item:hover {
    border-color: var(--dt3-primary);
    box-shadow: 0 10px 30px rgba(0, 137, 255, 0.1);
}

.m-icon {
    font-size: 32px;
    margin-bottom: 16px;
}

.matrix-item h4 {
    margin: 0 0 8px;
    font-size: 18px;
}

.matrix-item p {
    font-size: 14px;
    color: #6B7280;
    margin: 0;
}

/* New Feature Expansion Section */
.feature-expansion-section {
    padding: 80px 0;
    background: #fff;
}

.feature-group {
    margin-bottom: 100px;
}

.group-header {
    margin-bottom: 40px;
    text-align: left;
    border-left: 4px solid var(--dt3-primary);
    padding-left: 20px;
}

.group-header h3 {
    font-size: 28px;
    margin: 0 0 8px 0;
}

.group-header p {
    font-size: 16px;
    color: #6B7280;
    margin: 0;
}

.feature-cards-row {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
}

.feature-card-v3 {
    background: #F9FAFB;
    border-radius: 16px;
    padding: 32px;
    transition: all 0.3s;
    cursor: pointer;
    border: 1px solid transparent;
    position: relative;
    overflow: hidden;
}

.feature-card-v3:hover {
    background: #fff;
    box-shadow: 0 12px 32px rgba(0,0,0,0.08);
    transform: translateY(-5px);
    border-color: #E5E7EB;
}

/* Group 1 Styles */
.card-badge {
    background: #000;
    color: #fff;
    display: inline-block;
    padding: 4px 12px;
    border-radius: 4px;
    font-size: 12px;
    font-weight: bold;
    margin-bottom: 20px;
}

/* Group 2 Styles */
.icon-circle {
    width: 56px;
    height: 56px;
    background: #E6F7FF;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 28px;
    margin-bottom: 20px;
}

/* Group 3 Styles */
.icon-bg {
    font-size: 40px;
    opacity: 0.8;
    margin-bottom: 20px;
    background: linear-gradient(135deg, #E0F2FE 0%, #BAE6FD 100%);
    width: 80px;
    height: 80px;
    border-radius: 20px;
    display: flex;
    align-items: center;
    justify-content: center;
}

/* Group 4 Styles */
.card-image-placeholder {
    height: 140px;
    background-size: cover;
    background-position: center;
    border-radius: 8px;
    margin-bottom: 20px;
    opacity: 0.8;
}

.global-1 { background: linear-gradient(135deg, #A5F3FC 0%, #38BDF8 100%); }
.global-2 { background: linear-gradient(135deg, #FDE047 0%, #FACC15 100%); }
.global-3 { background: linear-gradient(135deg, #FDA4AF 0%, #F43F5E 100%); }

/* Group 5 Styles */
.dev-icon {
    font-family: monospace;
    font-size: 32px;
    color: var(--dt3-primary);
    background: #EFF6FF;
    padding: 16px;
    border-radius: 12px;
    display: inline-block;
    margin-bottom: 20px;
}

.feature-card-v3 h4 {
    margin: 0 0 12px;
    font-size: 20px;
    color: var(--dt3-text);
}

.feature-card-v3 p {
    margin: 0;
    font-size: 14px;
    color: #6B7280;
    line-height: 1.6;
}

/* Footer */
.official-footer {
    background: #fff;
    padding: 80px 0 40px;
    border-top: 1px solid #E5E7EB;
}

.footer-inner {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

.footer-links {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    margin-bottom: 60px;
}

.f-col h4 {
    margin-bottom: 24px;
    font-size: 16px;
}

.f-col a {
    display: block;
    margin-bottom: 12px;
    color: #6B7280;
    font-size: 14px;
}

.f-col a:hover {
    color: var(--dt3-primary);
}

.footer-legal {
    text-align: center;
    color: #9CA3AF;
    font-size: 12px;
    border-top: 1px solid #F3F4F6;
    padding-top: 40px;
}

.footer-legal p {
    margin: 8px 0;
}

/* Animations */
@keyframes float {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-15px); }
}

.fade-in {
    opacity: 0;
    transform: translateY(20px);
    animation: fadeInUp 0.8s ease-out forwards;
}

.delay-1 { animation-delay: 0.2s; }
.delay-2 { animation-delay: 0.4s; }
.delay-3 { animation-delay: 0.6s; }

@keyframes fadeInUp {
    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;
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
    animation: fadeInUp 0.3s ease-out;
}

.close-modal {
    position: absolute;
    right: 24px;
    top: 24px;
    font-size: 28px;
    color: #999;
    cursor: pointer;
    transition: color 0.2s;
}

.close-modal:hover {
    color: #333;
}