/* i4 Classic Style (Business Blue) */
:root {
    --primary-blue: #0056b3; /* Deep Royal Blue */
    --hover-blue: #004494;
    --light-blue: #e6f0fa;
    --text-dark: #333333;
    --text-gray: #666666;
    --border-color: #e0e0e0;
    --bg-light: #f8f9fa;
}

body {
    margin: 0;
    font-family: 'Roboto', 'Microsoft YaHei', sans-serif;
    color: var(--text-dark);
    background-color: #fff;
    line-height: 1.6;
}

a { text-decoration: none; color: inherit; }
ul { list-style: none; padding: 0; margin: 0; }

.container {
    width: 1200px;
    margin: 0 auto;
    padding: 0 15px;
    box-sizing: border-box;
}

/* Top Bar */
.top-bar {
    background-color: #f5f5f5;
    height: 30px;
    line-height: 30px;
    font-size: 12px;
    color: #999;
    border-bottom: 1px solid #eee;
}

.top-inner {
    display: flex;
    justify-content: space-between;
}

.top-right a { color: #666; }
.top-right a:hover { color: var(--primary-blue); }
.sep { margin: 0 10px; color: #ddd; }

/* Header */
.main-header {
    height: 80px;
    background: #fff;
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
    position: relative;
    z-index: 100;
}

.header-inner {
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

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

.logo-img {
    width: 40px;
    height: 40px;
    background: var(--primary-blue);
    color: white;
    font-weight: bold;
    font-size: 20px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 4px;
}

.logo-txt h1 { margin: 0; font-size: 24px; color: #333; line-height: 1; }
.logo-txt p { margin: 2px 0 0; font-size: 12px; color: #999; letter-spacing: 1px; }

.main-nav { display: flex; gap: 5px; }

.nav-link {
    display: block;
    padding: 0 20px;
    height: 80px;
    line-height: 80px;
    font-size: 16px;
    color: #333;
    font-weight: 500;
    transition: color 0.2s;
}

.nav-link:hover, .nav-link.active {
    color: var(--primary-blue);
    border-bottom: 3px solid var(--primary-blue);
    background: #fafafa;
}

/* Banner */
.banner-section {
    background: linear-gradient(135deg, #0056b3 0%, #003d80 100%);
    padding: 60px 0;
    color: white;
    height: 450px;
    display: flex;
    align-items: center;
}

.banner-inner {
    display: flex;
    align-items: center;
    justify-content: center;
}

.banner-text { width: 50%; }

.banner-text.centered {
    width: 100%;
    text-align: center;
    max-width: 800px;
}

.banner-text.centered .dl-group {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.banner-text h2 {
    font-size: 42px;
    margin-bottom: 20px;
    font-weight: 700;
}

.banner-desc {
    font-size: 16px;
    margin-bottom: 40px;
    opacity: 0.9;
    line-height: 1.8;
}

.dl-btn-primary {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    background: #fff;
    color: var(--primary-blue);
    padding: 15px 40px;
    border-radius: 4px;
    font-size: 18px;
    font-weight: bold;
    transition: background 0.2s;
}

.dl-btn-primary:hover { background: #f0f0f0; }

.dl-info {
    margin-top: 15px;
    font-size: 13px;
    opacity: 0.7;
}

.dl-info span { margin-right: 15px; }

/* CSS Mockup Elements */
.sw-header { height: 40px; background: #0056b3; display: flex; align-items: center; padding-left: 15px; }
.sw-header::before { content: ""; display: block; width: 10px; height: 10px; background: #ff5f56; border-radius: 50%; box-shadow: 15px 0 0 #ffbd2e, 30px 0 0 #27c93f; }

.sw-body { flex: 1; display: flex; height: calc(100% - 40px); }
.sw-sidebar { width: 80px; background: #f0f0f0; border-right: 1px solid #ddd; padding: 15px 10px; display: flex; flex-direction: column; gap: 10px; }
.sw-line { height: 6px; background: #d0d0d0; border-radius: 3px; width: 100%; }

.sw-main { flex: 1; padding: 20px; background: #fff; }
.sw-device-card { display: flex; gap: 15px; margin-bottom: 25px; padding-bottom: 20px; border-bottom: 1px solid #eee; }
.sw-device-img { width: 50px; height: 80px; background: #333; border-radius: 6px; position: relative; }
.sw-device-img::after { content: ""; position: absolute; top: 5px; left: 5px; right: 5px; bottom: 5px; background: #555; }
.sw-device-info-text { flex: 1; display: flex; flex-direction: column; gap: 8px; justify-content: center; }
.sw-text-line { height: 8px; background: #eee; border-radius: 4px; }
.l1 { width: 60%; background: #333; } .l2 { width: 40%; } .l3 { width: 30%; }

.sw-grid-icons { display: flex; gap: 15px; }
.sw-icon { width: 50px; height: 50px; background: #e6f0fa; border-radius: 10px; }

/* App Market UI Mockup */
.app-market-ui { display: flex; flex-direction: column; gap: 15px; padding: 30px; align-items: stretch; background: #f9f9f9; }
.app-item { display: flex; align-items: center; gap: 15px; background: white; padding: 10px; border-radius: 8px; border: 1px solid #eee; }
.app-icon { width: 40px; height: 40px; border-radius: 8px; }
.a-red { background: #ff7675; } .a-green { background: #55efc4; } .a-blue { background: #74b9ff; }
.app-info { flex: 1; display: flex; flex-direction: column; gap: 6px; }
.app-name { width: 50%; height: 8px; background: #333; border-radius: 4px; }
.app-btn { width: 60px; height: 20px; background: #0056b3; border-radius: 10px; align-self: flex-end; }

/* Flash UI Mockup */
.flash-ui { display: flex; flex-direction: column; padding: 0; overflow: hidden; background: white; }
.flash-header { height: 40px; border-bottom: 1px solid #eee; display: flex; }
.flash-tab { padding: 0 20px; line-height: 40px; font-size: 12px; color: #666; border-right: 1px solid #eee; background: #f9f9f9; }
.flash-tab.active { background: white; color: #0056b3; font-weight: bold; border-top: 2px solid #0056b3; }
.flash-list { padding: 20px; display: flex; flex-direction: column; gap: 15px; }
.flash-row { display: flex; justify-content: space-between; align-items: center; padding-bottom: 10px; border-bottom: 1px dashed #eee; }
.ver-tag { font-weight: bold; color: #333; }
.status-tag { font-size: 12px; color: #52c41a; background: #f6ffed; padding: 2px 8px; border: 1px solid #b7eb8f; border-radius: 4px; }
.flash-progress { height: 6px; background: #eee; border-radius: 3px; margin-top: 10px; overflow: hidden; }
.fp-bar { height: 100%; background: #0056b3; }

/* Core Features */
.core-section { padding: 60px 0; background: #fff; }

.section-head { text-align: center; margin-bottom: 50px; }
.section-head h3 { font-size: 32px; margin-bottom: 15px; color: #333; }
.divider { width: 60px; height: 4px; background: var(--primary-blue); margin: 0 auto; }

.core-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 30px;
}

.core-item {
    text-align: center;
    padding: 30px 20px;
    border: 1px solid #eee;
    transition: all 0.3s;
    background: #fcfcfc;
}

.core-item:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgba(0,0,0,0.08);
    border-color: var(--primary-blue);
}

.c-icon {
    width: 60px;
    height: 60px;
    margin: 0 auto 20px;
    background: var(--light-blue);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 24px;
    color: var(--primary-blue);
}

.icon-cloud::after { content: "☁️"; }
.icon-flash::after { content: "⚡"; }
.icon-tool::after { content: "🛠️"; }
.icon-check::after { content: "🔍"; }

.core-item h4 { font-size: 18px; margin-bottom: 10px; color: #333; }
.core-item p { font-size: 14px; color: #666; line-height: 1.6; }

/* Details */
.detail-section { padding: 80px 0; background: #f9f9f9; }

.detail-row {
    display: flex;
    align-items: center;
    gap: 60px;
    margin-bottom: 80px;
}

.detail-row:last-child { margin-bottom: 0; }
.detail-row.reverse { flex-direction: row-reverse; }

.detail-img { flex: 1; }

.screenshot-box {
    width: 100%;
    height: 300px;
    background: white;
    border: 1px solid #e0e0e0;
    box-shadow: 0 10px 30px rgba(0,0,0,0.05);
    display: flex;
    align-items: center;
    justify-content: center;
    color: #ccc;
    font-size: 14px;
}

.detail-text { flex: 1; }

.detail-text h3 { font-size: 28px; margin-bottom: 20px; color: #333; }
.detail-text ul { margin-bottom: 30px; }
.detail-text li {
    margin-bottom: 12px;
    padding-left: 20px;
    position: relative;
    color: #555;
}

.detail-text li::before {
    content: "•";
    color: var(--primary-blue);
    font-weight: bold;
    position: absolute;
    left: 0;
}

.link-btn {
    color: var(--primary-blue);
    font-weight: 600;
    border: 1px solid var(--primary-blue);
    padding: 8px 20px;
    border-radius: 4px;
    font-size: 14px;
    transition: all 0.2s;
}

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

/* Footer */
.main-footer {
    background: #333;
    color: #999;
    padding-top: 60px;
    font-size: 14px;
}

.footer-cols {
    display: flex;
    justify-content: space-between;
    margin-bottom: 50px;
    padding-bottom: 50px;
    border-bottom: 1px solid #444;
}

.f-col h4 { color: #fff; margin-bottom: 20px; font-size: 16px; }
.f-col a { display: block; margin-bottom: 10px; color: #999; }
.f-col a:hover { color: #fff; }

.contact p { margin-bottom: 10px; }

.footer-bar {
    text-align: center;
    padding-bottom: 30px;
    font-size: 12px;
}

.footer-bar p { margin: 5px 0; }