/* ========================================
   钉钉官网 - 全局样式
   ======================================== */

/* CSS Variables */
:root {
    --dt-blue: #0084FF;
    --dt-blue-dark: #0052D9;
    --dt-blue-light: #E8F4FF;
    --dt-blue-hover: #0066CC;
    --dt-dark: #171A2F;
    --dt-gray-1: #333333;
    --dt-gray-2: #555555;
    --dt-gray-3: #888888;
    --dt-gray-4: #B0B8C4;
    --dt-bg-light: #F5F7FA;
    --dt-bg-gray: #EEF1F6;
    --dt-white: #FFFFFF;
    --dt-orange: #FF6A00;
    --dt-green: #00C853;
    --dt-shadow: 0 4px 16px rgba(0, 132, 255, 0.08);
    --dt-shadow-hover: 0 12px 32px rgba(0, 132, 255, 0.16);
    --dt-radius: 12px;
    --dt-radius-sm: 8px;
    --dt-max-width: 1200px;
    --dt-transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

/* Reset */
*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", sans-serif;
    line-height: 1.7;
    color: var(--dt-dark);
    background: var(--dt-white);
    -webkit-font-smoothing: antialiased;
}

a {
    text-decoration: none;
    color: inherit;
}

ul, ol {
    list-style: none;
}

img {
    max-width: 100%;
    height: auto;
}

/* ========================================
   Header & Navigation
   ======================================== */
.site-header {
    background: var(--dt-white);
    box-shadow: 0 2px 12px rgba(0, 0, 0, 0.06);
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 1000;
    transition: var(--dt-transition);
}

.site-header.scrolled {
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
}

.main-nav {
    max-width: var(--dt-max-width);
    margin: 0 auto;
    padding: 0 32px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 72px;
}

.nav-brand {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 22px;
    font-weight: 700;
    color: var(--dt-dark);
}

.nav-brand img,
.nav-brand svg {
    width: 44px;
    height: 44px;
}

.nav-menu {
    display: flex;
    gap: 8px;
}

.nav-menu a {
    padding: 8px 20px;
    border-radius: 6px;
    font-size: 15px;
    color: var(--dt-gray-2);
    transition: var(--dt-transition);
    font-weight: 500;
}

.nav-menu a:hover {
    color: var(--dt-blue);
    background: var(--dt-blue-light);
}

.nav-menu a.active {
    color: var(--dt-blue);
    background: var(--dt-blue-light);
    font-weight: 600;
}

.nav-actions {
    display: flex;
    gap: 12px;
    align-items: center;
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 10px 28px;
    border-radius: 6px;
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    transition: var(--dt-transition);
    border: none;
    outline: none;
}

.btn-primary {
    background: var(--dt-blue);
    color: white;
}

.btn-primary:hover {
    background: var(--dt-blue-hover);
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(0, 132, 255, 0.3);
}

.btn-outline {
    background: transparent;
    color: var(--dt-blue);
    border: 2px solid var(--dt-blue);
}

.btn-outline:hover {
    background: var(--dt-blue);
    color: white;
}

.btn-white {
    background: white;
    color: var(--dt-blue);
}

.btn-white:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.15);
}

.btn-lg {
    padding: 16px 48px;
    font-size: 16px;
    border-radius: 8px;
}

/* Mobile Menu */
.mobile-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    cursor: pointer;
    padding: 8px;
}

.mobile-toggle span {
    width: 24px;
    height: 2px;
    background: var(--dt-dark);
    transition: var(--dt-transition);
}

/* ========================================
   Page Banner
   ======================================== */
.page-banner {
    margin-top: 72px;
    background: linear-gradient(135deg, var(--dt-blue) 0%, var(--dt-blue-dark) 100%);
    color: white;
    padding: 80px 32px;
    text-align: center;
    position: relative;
    overflow: hidden;
}

.page-banner::before {
    content: '';
    position: absolute;
    top: -50%;
    right: -10%;
    width: 600px;
    height: 600px;
    background: rgba(255, 255, 255, 0.05);
    border-radius: 50%;
}

.page-banner::after {
    content: '';
    position: absolute;
    bottom: -30%;
    left: -5%;
    width: 400px;
    height: 400px;
    background: rgba(255, 255, 255, 0.03);
    border-radius: 50%;
}

.page-banner h1 {
    font-size: 48px;
    font-weight: 700;
    margin-bottom: 16px;
    position: relative;
    z-index: 1;
}

.page-banner p {
    font-size: 20px;
    opacity: 0.9;
    max-width: 600px;
    margin: 0 auto;
    position: relative;
    z-index: 1;
}

/* ========================================
   Section Styles
   ======================================== */
.section {
    padding: 100px 32px;
}

.section-light {
    background: var(--dt-bg-light);
}

.section-white {
    background: var(--dt-white);
}

.section-blue {
    background: linear-gradient(135deg, var(--dt-blue-light) 0%, #F0F7FF 100%);
}

.container {
    max-width: var(--dt-max-width);
    margin: 0 auto;
}

.section-header {
    text-align: center;
    margin-bottom: 64px;
}

.section-header h2 {
    font-size: 40px;
    font-weight: 700;
    color: var(--dt-dark);
    margin-bottom: 16px;
}

.section-header p {
    font-size: 18px;
    color: var(--dt-gray-3);
    max-width: 600px;
    margin: 0 auto;
}

.section-header .subtitle-tag {
    display: inline-block;
    background: var(--dt-blue-light);
    color: var(--dt-blue);
    padding: 6px 20px;
    border-radius: 20px;
    font-size: 14px;
    font-weight: 600;
    margin-bottom: 20px;
}

/* ========================================
   Feature Cards
   ======================================== */
.features-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 32px;
}

.feature-card {
    background: var(--dt-white);
    padding: 40px 32px;
    border-radius: var(--dt-radius);
    box-shadow: var(--dt-shadow);
    transition: var(--dt-transition);
    position: relative;
    overflow: hidden;
}

.feature-card::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 4px;
    background: var(--dt-blue);
    transform: scaleX(0);
    transition: var(--dt-transition);
}

.feature-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--dt-shadow-hover);
}

.feature-card:hover::after {
    transform: scaleX(1);
}

.feature-card .card-icon {
    width: 72px;
    height: 72px;
    background: var(--dt-blue-light);
    border-radius: 16px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 24px;
    font-size: 32px;
    transition: var(--dt-transition);
}

.feature-card:hover .card-icon {
    background: var(--dt-blue);
    transform: scale(1.05);
}

.feature-card h3 {
    font-size: 22px;
    font-weight: 600;
    margin-bottom: 12px;
    color: var(--dt-dark);
}

.feature-card p {
    font-size: 15px;
    color: var(--dt-gray-3);
    line-height: 1.7;
}

.feature-card .card-link {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    color: var(--dt-blue);
    font-size: 14px;
    font-weight: 600;
    margin-top: 20px;
    transition: var(--dt-transition);
}

.feature-card .card-link:hover {
    gap: 10px;
}

/* ========================================
   Stats Section
   ======================================== */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 40px;
    text-align: center;
}

.stat-item {
    padding: 24px;
}

.stat-number {
    font-size: 56px;
    font-weight: 800;
    color: var(--dt-blue);
    line-height: 1.1;
    margin-bottom: 12px;
}

.stat-label {
    font-size: 16px;
    color: var(--dt-gray-2);
    font-weight: 500;
}

.stat-desc {
    font-size: 13px;
    color: var(--dt-gray-4);
    margin-top: 8px;
}

/* ========================================
   Feature Detail Layout
   ======================================== */
.feature-detail {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 80px;
    align-items: center;
    margin-bottom: 120px;
}

.feature-detail:last-child {
    margin-bottom: 0;
}

.feature-detail.reverse {
    direction: rtl;
}

.feature-detail.reverse > * {
    direction: ltr;
}

.feature-detail-text h2 {
    font-size: 36px;
    font-weight: 700;
    margin-bottom: 20px;
    color: var(--dt-dark);
}

.feature-detail-text .tag {
    display: inline-block;
    background: var(--dt-blue-light);
    color: var(--dt-blue);
    padding: 4px 16px;
    border-radius: 4px;
    font-size: 13px;
    font-weight: 600;
    margin-bottom: 20px;
}

.feature-detail-text p {
    font-size: 16px;
    color: var(--dt-gray-2);
    line-height: 1.8;
    margin-bottom: 24px;
}

.feature-detail-text ul {
    margin-bottom: 32px;
}

.feature-detail-text ul li {
    padding: 10px 0;
    color: var(--dt-gray-2);
    font-size: 15px;
    display: flex;
    align-items: center;
    gap: 12px;
}

.feature-detail-text ul li .check {
    width: 24px;
    height: 24px;
    background: var(--dt-blue-light);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--dt-blue);
    font-size: 12px;
    font-weight: bold;
    flex-shrink: 0;
}

.feature-detail-img {
    background: linear-gradient(135deg, var(--dt-blue-light) 0%, #F0F7FF 100%);
    border-radius: var(--dt-radius);
    height: 420px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 140px;
    box-shadow: var(--dt-shadow);
    position: relative;
    overflow: hidden;
}

.feature-detail-img::before {
    content: '';
    position: absolute;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle, rgba(0, 132, 255, 0.06) 0%, transparent 70%);
    animation: pulse 4s ease-in-out infinite;
}

@keyframes pulse {
    0%, 100% { transform: scale(1); opacity: 1; }
    50% { transform: scale(1.1); opacity: 0.5; }
}

/* ========================================
   Download Cards
   ======================================== */
.download-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 24px;
}

.download-card {
    background: var(--dt-white);
    border-radius: var(--dt-radius);
    padding: 48px 24px;
    text-align: center;
    box-shadow: var(--dt-shadow);
    transition: var(--dt-transition);
    border: 2px solid transparent;
}

.download-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--dt-shadow-hover);
    border-color: var(--dt-blue);
}

.download-card .platform-icon {
    font-size: 72px;
    margin-bottom: 20px;
}

.download-card h3 {
    font-size: 22px;
    font-weight: 600;
    margin-bottom: 8px;
    color: var(--dt-dark);
}

.download-card .version {
    font-size: 13px;
    color: var(--dt-gray-4);
    margin-bottom: 8px;
}

.download-card .system-req {
    font-size: 14px;
    color: var(--dt-gray-3);
    margin-bottom: 28px;
}

/* ========================================
   Solution Cards
   ======================================== */
.solution-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 32px;
}

.solution-card {
    background: var(--dt-white);
    border-radius: var(--dt-radius);
    overflow: hidden;
    box-shadow: var(--dt-shadow);
    transition: var(--dt-transition);
}

.solution-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--dt-shadow-hover);
}

.solution-card .card-header {
    height: 200px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 80px;
    position: relative;
}

.solution-card .card-body {
    padding: 32px;
}

.solution-card h3 {
    font-size: 22px;
    font-weight: 600;
    margin-bottom: 12px;
    color: var(--dt-dark);
}

.solution-card p {
    font-size: 15px;
    color: var(--dt-gray-3);
    margin-bottom: 20px;
    line-height: 1.7;
}

.solution-card .tag-list {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.solution-card .tag-list span {
    background: var(--dt-blue-light);
    color: var(--dt-blue);
    padding: 4px 12px;
    border-radius: 4px;
    font-size: 12px;
    font-weight: 500;
}

/* ========================================
   Timeline
   ======================================== */
.timeline {
    position: relative;
    max-width: 800px;
    margin: 0 auto;
}

.timeline::before {
    content: '';
    position: absolute;
    left: 50%;
    transform: translateX(-50%);
    width: 3px;
    height: 100%;
    background: linear-gradient(to bottom, var(--dt-blue-light), var(--dt-blue));
    border-radius: 2px;
}

.timeline-item {
    position: relative;
    padding: 24px 0;
}

.timeline-item:nth-child(odd) {
    padding-right: calc(50% + 40px);
    text-align: right;
}

.timeline-item:nth-child(even) {
    padding-left: calc(50% + 40px);
    text-align: left;
}

.timeline-dot {
    position: absolute;
    left: 50%;
    top: 32px;
    transform: translateX(-50%);
    width: 16px;
    height: 16px;
    background: var(--dt-blue);
    border-radius: 50%;
    border: 3px solid white;
    box-shadow: 0 0 0 3px var(--dt-blue-light);
    z-index: 1;
}

.timeline-content {
    background: var(--dt-white);
    padding: 28px;
    border-radius: var(--dt-radius-sm);
    box-shadow: var(--dt-shadow);
    transition: var(--dt-transition);
}

.timeline-content:hover {
    box-shadow: var(--dt-shadow-hover);
}

.timeline-year {
    font-size: 28px;
    font-weight: 800;
    color: var(--dt-blue);
    margin-bottom: 8px;
}

.timeline-content h4 {
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 8px;
    color: var(--dt-dark);
}

.timeline-content p {
    font-size: 14px;
    color: var(--dt-gray-3);
    line-height: 1.6;
}

/* ========================================
   Contact Cards
   ======================================== */
.contact-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 24px;
}

.contact-card {
    background: var(--dt-white);
    padding: 36px 24px;
    border-radius: var(--dt-radius-sm);
    text-align: center;
    box-shadow: var(--dt-shadow);
    transition: var(--dt-transition);
}

.contact-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--dt-shadow-hover);
}

.contact-card .icon {
    font-size: 48px;
    margin-bottom: 16px;
}

.contact-card h4 {
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 12px;
    color: var(--dt-dark);
}

.contact-card p {
    font-size: 14px;
    color: var(--dt-gray-3);
    line-height: 1.6;
}

/* ========================================
   Table
   ======================================== */
.data-table {
    width: 100%;
    border-collapse: collapse;
    background: white;
    border-radius: var(--dt-radius);
    overflow: hidden;
    box-shadow: var(--dt-shadow);
}

.data-table th {
    background: var(--dt-blue);
    color: white;
    padding: 16px 28px;
    text-align: left;
    font-weight: 600;
    font-size: 14px;
}

.data-table td {
    padding: 16px 28px;
    border-bottom: 1px solid var(--dt-bg-light);
    font-size: 15px;
    color: var(--dt-gray-2);
}

.data-table tr:last-child td {
    border-bottom: none;
}

.data-table tr:hover td {
    background: var(--dt-blue-light);
}

/* ========================================
   CTA Section
   ======================================== */
.cta-section {
    background: linear-gradient(135deg, var(--dt-blue) 0%, var(--dt-blue-dark) 100%);
    padding: 100px 32px;
    text-align: center;
    color: white;
    position: relative;
    overflow: hidden;
}

.cta-section::before {
    content: '';
    position: absolute;
    top: -200px;
    right: -200px;
    width: 500px;
    height: 500px;
    background: rgba(255, 255, 255, 0.04);
    border-radius: 50%;
}

.cta-section h2 {
    font-size: 42px;
    font-weight: 700;
    margin-bottom: 20px;
    position: relative;
    z-index: 1;
}

.cta-section p {
    font-size: 18px;
    opacity: 0.9;
    margin-bottom: 40px;
    position: relative;
    z-index: 1;
}

/* ========================================
   Footer
   ======================================== */
.site-footer {
    background: var(--dt-dark);
    color: white;
    padding: 80px 32px 40px;
}

.footer-grid {
    max-width: var(--dt-max-width);
    margin: 0 auto;
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr 1fr;
    gap: 48px;
    margin-bottom: 60px;
}

.footer-brand {
    padding-right: 40px;
}

.footer-brand .brand-name {
    font-size: 24px;
    font-weight: 700;
    margin-bottom: 16px;
    display: flex;
    align-items: center;
    gap: 12px;
}

.footer-brand .brand-name img,
.footer-brand .brand-name svg {
    width: 36px;
    height: 36px;
}

.footer-brand p {
    font-size: 14px;
    color: rgba(255, 255, 255, 0.6);
    line-height: 1.7;
    margin-bottom: 24px;
}

.footer-social {
    display: flex;
    gap: 16px;
}

.footer-social a {
    width: 40px;
    height: 40px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 18px;
    transition: var(--dt-transition);
}

.footer-social a:hover {
    background: var(--dt-blue);
}

.footer-column h5 {
    font-size: 16px;
    font-weight: 600;
    margin-bottom: 24px;
    color: white;
}

.footer-column ul li {
    margin-bottom: 14px;
}

.footer-column ul li a {
    font-size: 14px;
    color: rgba(255, 255, 255, 0.6);
    transition: var(--dt-transition);
}

.footer-column ul li a:hover {
    color: white;
    padding-left: 4px;
}

.footer-bottom {
    max-width: var(--dt-max-width);
    margin: 0 auto;
    padding-top: 40px;
    border-top: 1px solid rgba(255, 255, 255, 0.08);
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 13px;
    color: rgba(255, 255, 255, 0.4);
}

.footer-bottom-links {
    display: flex;
    gap: 24px;
}

.footer-bottom-links a {
    color: rgba(255, 255, 255, 0.4);
    transition: var(--dt-transition);
}

.footer-bottom-links a:hover {
    color: white;
}

/* ========================================
   Responsive
   ======================================== */
@media (max-width: 1024px) {
    .features-grid,
    .solution-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .download-grid,
    .contact-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .footer-grid {
        grid-template-columns: repeat(3, 1fr);
    }

    .feature-detail {
        gap: 48px;
    }
}

@media (max-width: 768px) {
    .nav-menu {
        display: none;
    }

    .mobile-toggle {
        display: flex;
    }

    .page-banner h1 {
        font-size: 32px;
    }

    .page-banner p {
        font-size: 16px;
    }

    .section-header h2 {
        font-size: 30px;
    }

    .features-grid,
    .solution-grid,
    .download-grid,
    .contact-grid {
        grid-template-columns: 1fr;
    }

    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 24px;
    }

    .feature-detail {
        grid-template-columns: 1fr;
        gap: 32px;
    }

    .feature-detail.reverse {
        direction: ltr;
    }

    .feature-detail-img {
        height: 280px;
        font-size: 100px;
    }

    .timeline::before {
        left: 20px;
    }

    .timeline-item:nth-child(odd),
    .timeline-item:nth-child(even) {
        padding-left: 60px;
        padding-right: 0;
        text-align: left;
    }

    .timeline-dot {
        left: 20px;
    }

    .footer-grid {
        grid-template-columns: 1fr 1fr;
    }

    .footer-bottom {
        flex-direction: column;
        gap: 16px;
        text-align: center;
    }

    .cta-section h2 {
        font-size: 30px;
    }
}

@media (max-width: 480px) {
    .stats-grid {
        grid-template-columns: 1fr;
    }

    .footer-grid {
        grid-template-columns: 1fr;
    }

    .stat-number {
        font-size: 42px;
    }
}