/* 基础样式 */
:root {
    --primary-color: #007bff;
    --primary-dark: #0056b3;
    --secondary-color: #6c757d;
    --success-color: #28a745;
    --warning-color: #ffc107;
    --danger-color: #dc3545;
    --bg-color: #f8f9fa;
    --card-bg: #ffffff;
    --text-color: #333333;
    --text-muted: #6c757d;
    --border-color: #dee2e6;
    --code-bg: #1e1e1e;
    --code-text: #d4d4d4;
    --shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    --shadow-hover: 0 5px 20px rgba(0, 0, 0, 0.15);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans SC", sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--bg-color);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* 导航栏 */
.navbar {
    background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: var(--shadow);
}

.navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    color: white;
    font-size: 1.5rem;
    font-weight: bold;
    text-decoration: none;
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 2rem;
}

.nav-links a {
    color: rgba(255, 255, 255, 0.9);
    text-decoration: none;
    padding: 0.5rem 1rem;
    border-radius: 5px;
    transition: all 0.3s ease;
}

.nav-links a:hover,
.nav-links a.active {
    background: rgba(255, 255, 255, 0.2);
    color: white;
}

/* 主内容区 */
main {
    padding: 2rem 0;
}

main h1 {
    font-size: 2rem;
    margin-bottom: 1.5rem;
    color: var(--primary-dark);
    border-bottom: 3px solid var(--primary-color);
    padding-bottom: 0.5rem;
}

main h2 {
    font-size: 1.5rem;
    margin: 2rem 0 1rem;
    color: var(--primary-dark);
}

main h3 {
    font-size: 1.2rem;
    margin: 1.5rem 0 0.8rem;
    color: var(--text-color);
}

main h4 {
    font-size: 1rem;
    margin: 1rem 0 0.5rem;
}

/* Broker 部分 */
.broker-section {
    margin: 3rem 0;
}

.broker-features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
    margin: 1.5rem 0;
}

.broker-feature {
    background: var(--card-bg);
    padding: 1.2rem;
    border-radius: 8px;
    box-shadow: var(--shadow);
    text-align: center;
}

.broker-feature h4 {
    margin-bottom: 0.5rem;
    color: var(--primary-color);
}

.broker-feature p {
    font-size: 0.9rem;
    color: var(--text-muted);
}

/* 部署网格 */
.deploy-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1.5rem;
    margin: 1.5rem 0;
}

.deploy-card {
    background: var(--card-bg);
    padding: 1.5rem;
    border-radius: 10px;
    box-shadow: var(--shadow);
    border-top: 4px solid var(--primary-color);
}

.deploy-card:nth-child(2) {
    border-top-color: var(--success-color);
}

.deploy-card:nth-child(3) {
    border-top-color: var(--warning-color);
}

.deploy-card h4 {
    margin-bottom: 1rem;
    font-size: 1.1rem;
}

.deploy-card ul {
    margin: 1rem 0;
    padding-left: 1.5rem;
}

.deploy-card li {
    margin-bottom: 0.4rem;
    font-size: 0.9rem;
}

.deploy-pros,
.deploy-cons {
    font-size: 0.85rem;
    margin-top: 0.8rem;
    padding: 0.5rem;
    border-radius: 5px;
}

.deploy-pros {
    background: rgba(40, 167, 69, 0.1);
    color: var(--success-color);
}

.deploy-cons {
    background: rgba(220, 53, 69, 0.1);
    color: var(--danger-color);
}

/* 部署架构部分 */
.deploy-section {
    margin: 3rem 0;
}

.deploy-info {
    background: var(--card-bg);
    padding: 1.5rem;
    border-radius: 10px;
    box-shadow: var(--shadow);
    margin: 1.5rem 0;
}

.deploy-info h4 {
    color: var(--primary-color);
    margin: 1rem 0 0.8rem;
}

.deploy-info h4:first-child {
    margin-top: 0;
}

.deploy-info ul {
    margin-left: 1.5rem;
    margin-bottom: 1rem;
}

.deploy-info li {
    margin-bottom: 0.4rem;
}

/* 传输协议部分 */
.transport-section {
    margin: 3rem 0;
}

.highlight-answer {
    background: linear-gradient(135deg, rgba(0, 123, 255, 0.1), rgba(102, 126, 234, 0.1));
    border-left: 4px solid var(--primary-color);
    padding: 1rem 1.5rem;
    border-radius: 0 8px 8px 0;
    font-size: 1.1rem;
    margin: 1.5rem 0;
}

.protocol-stack {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    margin: 1.5rem 0;
}

.stack-layer {
    display: flex;
    align-items: center;
    padding: 1rem 1.5rem;
    border-radius: 8px;
    gap: 1rem;
}

.stack-layer.app {
    background: linear-gradient(135deg, #667eea, #764ba2);
    color: white;
}

.stack-layer.transport {
    background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
    color: white;
}

.stack-layer.network {
    background: linear-gradient(135deg, #20c997, #128c7e);
    color: white;
}

.stack-layer.link {
    background: linear-gradient(135deg, #fd7e14, #e8590c);
    color: white;
}

.layer-name {
    font-weight: 600;
    min-width: 120px;
}

.layer-desc {
    opacity: 0.9;
}

.port-table {
    margin: 1.5rem 0;
}

/* 介绍区域 */
.intro {
    margin-bottom: 3rem;
}

.intro p {
    font-size: 1.1rem;
    margin-bottom: 1.5rem;
}

/* 特性网格 */
.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
    margin-top: 2rem;
}

.feature-card {
    background: var(--card-bg);
    padding: 1.5rem;
    border-radius: 10px;
    box-shadow: var(--shadow);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.feature-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-hover);
}

.feature-card h3 {
    margin-bottom: 0.8rem;
    color: var(--primary-color);
}

/* 架构图 */
.architecture {
    margin: 3rem 0;
}

.architecture-diagram {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 1rem;
    padding: 2rem;
    background: var(--card-bg);
    border-radius: 10px;
    box-shadow: var(--shadow);
    flex-wrap: wrap;
}

.arch-component {
    background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
    color: white;
    padding: 1.5rem 2rem;
    border-radius: 10px;
    text-align: center;
    min-width: 150px;
}

.arch-component h4 {
    margin-bottom: 0.5rem;
}

.arch-component .small {
    font-size: 0.85rem;
    opacity: 0.8;
}

.arch-arrow {
    font-size: 2rem;
    color: var(--primary-color);
}

.diagram-caption {
    text-align: center;
    margin-top: 1rem;
    color: var(--text-muted);
    font-style: italic;
}

/* 主题部分 */
.topics {
    margin: 3rem 0;
}

.code-block {
    background: var(--code-bg);
    color: var(--code-text);
    border-radius: 8px;
    overflow: hidden;
    margin: 1rem 0;
    font-family: "Fira Code", "Consolas", "Monaco", monospace;
    font-size: 0.9rem;
    line-height: 1.5;
}

.code-block.small {
    font-size: 0.8rem;
}

.code-block-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.8rem 1rem;
    background: rgba(255, 255, 255, 0.05);
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    cursor: pointer;
    user-select: none;
}

.code-block-header:hover {
    background: rgba(255, 255, 255, 0.08);
}

.code-block-title {
    font-size: 0.85rem;
    color: rgba(255, 255, 255, 0.7);
}

.code-block-toggle {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.8rem;
    color: rgba(255, 255, 255, 0.6);
    transition: transform 0.3s ease;
}

.code-block-toggle::before {
    content: "▼";
    font-size: 0.7rem;
    transition: transform 0.3s ease;
}

.code-block.collapsed .code-block-toggle::before {
    transform: rotate(-90deg);
}

.code-block-content {
    padding: 1.5rem;
    overflow-x: auto;
    transition: max-height 0.3s ease, opacity 0.3s ease;
    max-height: 2000px;
    opacity: 1;
}

.code-block.collapsed .code-block-content {
    max-height: 0;
    opacity: 0;
    padding-top: 0;
    padding-bottom: 0;
}

.code-block.small .code-block-content {
    padding: 1rem;
}

.code-block pre {
    margin: 0;
}

.code-block code {
    font-family: inherit;
}

/* 表格 */
.info-table {
    width: 100%;
    border-collapse: collapse;
    margin: 1rem 0;
    background: var(--card-bg);
    border-radius: 8px;
    overflow: hidden;
    box-shadow: var(--shadow);
}

.info-table th,
.info-table td {
    padding: 1rem;
    text-align: left;
    border-bottom: 1px solid var(--border-color);
}

.info-table th {
    background: var(--primary-color);
    color: white;
    font-weight: 600;
}

.info-table tr:hover {
    background: rgba(0, 123, 255, 0.05);
}

.info-table code {
    background: rgba(0, 0, 0, 0.1);
    padding: 0.2rem 0.5rem;
    border-radius: 3px;
    font-family: "Fira Code", monospace;
}

/* QoS 网格 */
.qos-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1.5rem;
    margin-top: 1.5rem;
}

.qos-card {
    background: var(--card-bg);
    padding: 1.5rem;
    border-radius: 10px;
    box-shadow: var(--shadow);
    border-top: 4px solid var(--secondary-color);
}

.qos-0 {
    border-top-color: var(--success-color);
}

.qos-1 {
    border-top-color: var(--warning-color);
}

.qos-2 {
    border-top-color: var(--danger-color);
}

.qos-card h3 {
    margin-bottom: 0.3rem;
}

.qos-name {
    color: var(--text-muted);
    font-style: italic;
    margin-bottom: 1rem;
}

.qos-flow {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-top: 1rem;
    padding: 0.8rem;
    background: var(--bg-color);
    border-radius: 5px;
    font-size: 0.85rem;
    flex-wrap: wrap;
}

.qos-flow span {
    background: var(--primary-color);
    color: white;
    padding: 0.3rem 0.6rem;
    border-radius: 3px;
    font-size: 0.75rem;
}

/* 序列图 */
.interaction-section {
    margin: 2rem 0;
}

.mermaid {
    background: var(--card-bg);
    padding: 2rem;
    border-radius: 10px;
    box-shadow: var(--shadow);
    margin: 1.5rem 0;
    display: flex;
    justify-content: center;
    overflow-x: auto;
}

.mermaid svg {
    max-width: 100%;
    height: auto;
}

/* 信息框 */
.info-box {
    background: rgba(0, 123, 255, 0.1);
    border-left: 4px solid var(--primary-color);
    padding: 1.5rem;
    border-radius: 0 8px 8px 0;
    margin: 1.5rem 0;
}

.info-box.warning {
    background: rgba(255, 193, 7, 0.1);
    border-left-color: var(--warning-color);
}

.info-box h4 {
    margin-bottom: 0.8rem;
    color: var(--primary-color);
}

.info-box.warning h4 {
    color: #b78900;
}

.info-box ul,
.info-box ol {
    margin-left: 1.5rem;
}

.info-box li {
    margin-bottom: 0.5rem;
}

.qos2-summary {
    margin-top: 1rem;
    padding: 0.8rem 1rem;
    background: rgba(40, 167, 69, 0.1);
    border-radius: 5px;
    color: var(--success-color);
    font-weight: 500;
}

/* 数据包结构 */
.packet-section {
    margin: 2rem 0;
}

.packet-structure {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    margin: 1.5rem 0;
}

.packet-structure.horizontal {
    flex-direction: row;
    flex-wrap: wrap;
    gap: 0.3rem;
}

.packet-structure.horizontal .packet-byte {
    flex: 1;
    min-width: 80px;
    font-size: 0.75rem;
    padding: 0.5rem 0.3rem;
}

.packet-structure.horizontal .bit-label {
    font-size: 0.65rem;
}

.packet-structure.horizontal .bit-value {
    font-size: 0.7rem;
}

.packet-structure.horizontal .bit-detail {
    font-size: 0.6rem;
}

.packet-row {
    display: flex;
    gap: 0.5rem;
}

.packet-byte {
    background: linear-gradient(135deg, #667eea, #764ba2);
    color: white;
    padding: 1rem;
    border-radius: 5px;
    text-align: center;
    min-width: 120px;
    flex: 1;
    transition: transform 0.3s ease;
}

.packet-byte:hover {
    transform: scale(1.02);
}

.packet-byte.highlight {
    background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
}

.packet-byte.conditional {
    background: linear-gradient(135deg, var(--warning-color), #e0a800);
    color: #333;
}

.packet-byte.payload {
    background: linear-gradient(135deg, var(--success-color), #218838);
}

.bit-label {
    display: block;
    font-size: 0.75rem;
    opacity: 0.8;
    margin-bottom: 0.3rem;
}

.bit-value {
    display: block;
    font-weight: 600;
}

.bit-detail {
    display: block;
    font-size: 0.75rem;
    opacity: 0.9;
    margin-top: 0.3rem;
}

/* 标志位图 */
.flags-diagram {
    display: inline-block;
    margin: 1rem 0;
}

.flag-bit {
    display: flex;
    gap: 2px;
}

.flag-bit span {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    background: var(--primary-color);
    color: white;
    border-radius: 5px;
    font-size: 0.85rem;
    font-weight: 600;
}

.flag-bit.values span {
    background: var(--primary-dark);
}

.flag-labels {
    display: flex;
    gap: 2px;
    margin-top: 5px;
}

.flag-label {
    font-size: 0.7rem;
    color: var(--text-muted);
    text-align: center;
    padding: 0.2rem;
}

.flag-type { background: #28a745 !important; }
.flag-dup { background: #17a2b8 !important; }
.flag-qos { background: #ffc107 !important; color: #333; }
.flag-retain { background: #dc3545 !important; }
.flag-username { background: #6f42c1 !important; }
.flag-password { background: #e83e8c !important; }
.flag-will-retain { background: #fd7e14 !important; }
.flag-will-qos { background: #20c997 !important; color: #333; }
.flag-will { background: #6610f2 !important; }
.flag-clean { background: #343a40 !important; }

/* 编码演示 */
.encoding-demo {
    background: var(--card-bg);
    padding: 1.5rem;
    border-radius: 8px;
    box-shadow: var(--shadow);
    margin: 1rem 0;
}

.encoding-row {
    display: grid;
    grid-template-columns: 2fr 1fr 2fr;
    gap: 1rem;
    padding: 0.8rem;
    border-bottom: 1px solid var(--border-color);
}

.encoding-row:last-child {
    border-bottom: none;
}

.encoding-label {
    font-weight: 600;
}

.encoding-value {
    color: var(--primary-color);
}

.encoding-example code {
    background: var(--code-bg);
    color: var(--code-text);
    padding: 0.2rem 0.5rem;
    border-radius: 3px;
}

/* 示例参数 */
.example-params {
    list-style: none;
    margin: 1rem 0;
}

.example-params li {
    padding: 0.5rem 0;
    border-bottom: 1px solid var(--border-color);
}

.example-params code {
    background: var(--code-bg);
    color: var(--code-text);
    padding: 0.2rem 0.5rem;
    border-radius: 3px;
}

/* 应用部分 */
.app-section {
    background: var(--card-bg);
    padding: 2rem;
    border-radius: 10px;
    box-shadow: var(--shadow);
    margin: 2rem 0;
}

.app-diagram {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 1rem;
    padding: 2rem;
    background: var(--bg-color);
    border-radius: 8px;
    margin: 1.5rem 0;
    flex-wrap: wrap;
}

.app-device,
.app-broker,
.app-server {
    background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
    color: white;
    padding: 1.5rem;
    border-radius: 10px;
    min-width: 150px;
}

.app-device ul,
.app-server ul {
    margin-top: 0.5rem;
    margin-left: 1.2rem;
    font-size: 0.9rem;
}

.app-arrow {
    font-size: 1.5rem;
    color: var(--primary-color);
}

/* 智能家居图 */
.smart-home-diagram {
    background: var(--bg-color);
    padding: 2rem;
    border-radius: 10px;
    margin: 1.5rem 0;
}

.sh-center {
    text-align: center;
    padding: 1.5rem;
    background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
    color: white;
    border-radius: 10px;
    margin-bottom: 1.5rem;
}

.sh-devices {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
}

.sh-device {
    background: var(--card-bg);
    padding: 1rem;
    border-radius: 8px;
    box-shadow: var(--shadow);
}

.sh-device span {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 600;
}

.sh-device code {
    font-size: 0.8rem;
    background: var(--code-bg);
    color: var(--code-text);
    padding: 0.2rem 0.5rem;
    border-radius: 3px;
    display: block;
}

/* 代码示例页面 */
.code-section {
    margin: 2rem 0;
}

.lang-tabs {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 1.5rem;
}

.lang-tab {
    padding: 0.8rem 1.5rem;
    border: none;
    background: var(--card-bg);
    color: var(--text-color);
    cursor: pointer;
    border-radius: 8px 8px 0 0;
    font-size: 1rem;
    transition: all 0.3s ease;
}

.lang-tab:hover {
    background: var(--primary-color);
    color: white;
}

.lang-tab.active {
    background: var(--primary-color);
    color: white;
}

.install-hint {
    background: rgba(0, 123, 255, 0.1);
    padding: 0.8rem 1rem;
    border-radius: 5px;
    margin-bottom: 1.5rem;
}

.install-hint code {
    background: var(--code-bg);
    color: var(--code-text);
    padding: 0.2rem 0.5rem;
    border-radius: 3px;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .nav-links {
        gap: 1rem;
    }
    
    .nav-links a {
        padding: 0.3rem 0.5rem;
        font-size: 0.9rem;
    }
    
    .hero h1 {
        font-size: 1.8rem;
    }
    
    .architecture-diagram {
        flex-direction: column;
    }
    
    .arch-arrow {
        transform: rotate(90deg);
    }
    
    .qos-grid {
        grid-template-columns: 1fr;
    }
    
    .features-grid {
        grid-template-columns: 1fr;
    }
    
    .encoding-row {
        grid-template-columns: 1fr;
        gap: 0.5rem;
    }
    
    .sequence-diagram {
        padding: 1rem;
    }
    
    .message-line {
        width: 100px;
    }
}

/* 动画效果 */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.feature-card,
.qos-card,
.app-section {
    animation: fadeIn 0.5s ease-out;
}

/* 打印样式 */
@media print {
    .navbar,
    .hero,
    footer {
        display: none;
    }
    
    body {
        background: white;
        color: black;
    }
    
    .code-block {
        background: #f5f5f5;
        color: black;
        border: 1px solid #ddd;
    }
}