/* =============================================
   MachModel - 斯特博机电科技 企业官网样式
   ============================================= */

/* CSS 变量定义 */
:root {
    --color-primary: #0B2545;
    --color-primary-light: #134074;
    --color-primary-lighter: #1B3A6B;
    --color-accent: #2563EB;
    --color-accent-light: #3B82F6;
    --color-accent-bg: #EFF6FF;
    --color-secondary: #8DA9C4;
    --color-bg: #F7F9FC;
    --color-bg-alt: #EEF2F7;
    --color-white: #FFFFFF;
    --color-text: #2D3748;
    --color-text-secondary: #718096;
    --color-text-light: #A0AEC0;
    --color-border: #E2E8F0;
    --color-success: #10B981;
    --color-warning: #F59E0B;
    --color-dev: #8B5CF6;
    --font-stack: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
    --font-mono: "JetBrains Mono", "Fira Code", monospace;
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.08);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 8px 30px rgba(0, 0, 0, 0.12);
    --shadow-xl: 0 16px 48px rgba(0, 0, 0, 0.15);
    --radius-sm: 6px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --transition: 0.3s ease;
    --max-width: 1200px;
}

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

html {
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-stack);
    font-size: 16px;
    line-height: 1.6;
    color: var(--color-text);
    background-color: var(--color-bg);
    overflow-x: hidden;
}

.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 24px;
}

a {
    color: var(--color-accent);
    text-decoration: none;
    transition: color var(--transition);
}

a:hover {
    color: var(--color-accent-light);
}

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

/* =============================================
   导航栏
   ============================================= */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid transparent;
    transition: all var(--transition);
    padding: 0 24px;
}

.navbar.scrolled {
    border-bottom-color: var(--color-border);
    box-shadow: var(--shadow-sm);
}

.nav-container {
    max-width: var(--max-width);
    margin: 0 auto;
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 64px;
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: 8px;
    text-decoration: none;
    color: var(--color-primary);
    font-weight: 700;
}

.logo-icon {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 36px;
    height: 36px;
    background: var(--color-primary);
    color: var(--color-white);
    border-radius: var(--radius-sm);
    font-size: 18px;
    font-weight: 800;
    letter-spacing: -1px;
}

.logo-text {
    font-size: 20px;
    letter-spacing: -0.5px;
}

.nav-menu {
    display: flex;
    align-items: center;
    gap: 8px;
    list-style: none;
}

.nav-link {
    display: block;
    padding: 8px 16px;
    font-size: 15px;
    color: var(--color-text-secondary);
    border-radius: var(--radius-sm);
    transition: all var(--transition);
}

.nav-link:hover,
.nav-link.active {
    color: var(--color-accent);
    background: var(--color-accent-bg);
}

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 8px;
}

.nav-toggle span {
    display: block;
    width: 24px;
    height: 2px;
    background: var(--color-text);
    border-radius: 2px;
    transition: all var(--transition);
}

.nav-toggle.active span:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
}

.nav-toggle.active span:nth-child(2) {
    opacity: 0;
}

.nav-toggle.active span:nth-child(3) {
    transform: rotate(-45deg) translate(5px, -5px);
}

/* =============================================
   英雄区
   ============================================= */
.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-light) 50%, var(--color-primary-lighter) 100%);
    color: var(--color-white);
    overflow: hidden;
    padding-top: 64px;
}

.hero-bg-pattern {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    opacity: 0.08;
    background-image: 
        radial-gradient(circle at 25% 25%, rgba(255,255,255,0.2) 1px, transparent 1px),
        radial-gradient(circle at 75% 75%, rgba(255,255,255,0.15) 1px, transparent 1px);
    background-size: 60px 60px;
}

.hero-content {
    position: relative;
    z-index: 1;
    text-align: center;
    max-width: 800px;
    padding: 60px 24px;
}

.hero-title {
    font-size: 56px;
    font-weight: 800;
    line-height: 1.2;
    letter-spacing: -1px;
    margin-bottom: 24px;
}

.hero-title-line1 {
    display: block;
    opacity: 0;
    animation: fadeInUp 0.8s ease forwards;
}

.hero-title-line2 {
    display: block;
    opacity: 0;
    animation: fadeInUp 0.8s ease 0.2s forwards;
    color: var(--color-accent-light);
}

.hero-subtitle {
    font-size: 20px;
    color: var(--color-secondary);
    line-height: 1.5;
    margin-bottom: 40px;
    opacity: 0;
    animation: fadeInUp 0.8s ease 0.4s forwards;
}

.hero-actions {
    display: flex;
    gap: 16px;
    justify-content: center;
    margin-bottom: 48px;
    opacity: 0;
    animation: fadeInUp 0.8s ease 0.6s forwards;
}

.hero-stats {
    display: flex;
    gap: 40px;
    justify-content: center;
    opacity: 0;
    animation: fadeInUp 0.8s ease 0.8s forwards;
}

.stat-item {
    text-align: center;
}

.stat-number {
    display: block;
    font-size: 36px;
    font-weight: 700;
    color: var(--color-white);
}

.stat-label {
    display: block;
    font-size: 14px;
    color: var(--color-secondary);
    margin-top: 4px;
}

.stat-tag {
    display: inline-block;
    padding: 6px 16px;
    background: rgba(16, 185, 129, 0.2);
    border: 1px solid rgba(16, 185, 129, 0.4);
    border-radius: var(--radius-sm);
    color: #6EE7B7;
    font-size: 14px;
    font-weight: 500;
}

/* =============================================
   按钮
   ============================================= */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 12px 24px;
    font-size: 16px;
    font-weight: 600;
    font-family: var(--font-stack);
    border-radius: var(--radius-sm);
    border: 2px solid transparent;
    cursor: pointer;
    transition: all var(--transition);
    text-decoration: none;
}

.btn-primary {
    background: var(--color-accent);
    color: var(--color-white);
    border-color: var(--color-accent);
}

.btn-primary:hover {
    background: var(--color-accent-light);
    border-color: var(--color-accent-light);
    color: var(--color-white);
    transform: translateY(-2px);
    box-shadow: 0 4px 16px rgba(37, 99, 235, 0.3);
}

.btn-outline {
    background: transparent;
    color: var(--color-white);
    border-color: rgba(255, 255, 255, 0.3);
}

.btn-outline:hover {
    background: rgba(255, 255, 255, 0.1);
    border-color: rgba(255, 255, 255, 0.6);
    color: var(--color-white);
    transform: translateY(-2px);
}

.btn-outline-light {
    background: transparent;
    color: var(--color-accent);
    border-color: var(--color-accent);
}

.btn-outline-light:hover {
    background: var(--color-accent);
    color: var(--color-white);
    transform: translateY(-2px);
}

.btn-sm {
    padding: 8px 20px;
    font-size: 14px;
}

.btn-large {
    padding: 16px 40px;
    font-size: 18px;
}

.btn-block {
    width: 100%;
}

/* =============================================
   通用板块样式
   ============================================= */
.section {
    padding: 100px 0;
}

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

.section-title {
    font-size: 36px;
    font-weight: 700;
    color: var(--color-primary);
    letter-spacing: -0.5px;
    margin-bottom: 16px;
}

.section-desc {
    font-size: 18px;
    color: var(--color-text-secondary);
    max-width: 600px;
    margin: 0 auto;
}

/* =============================================
   企业介绍
   ============================================= */
.section-about {
    background: var(--color-white);
}

.about-grid {
    display: grid;
    grid-template-columns: 1fr 340px;
    gap: 40px;
    align-items: start;
}

.about-company-name {
    font-size: 24px;
    font-weight: 700;
    color: var(--color-primary);
    margin-bottom: 8px;
}

.about-founded {
    font-size: 16px;
    color: var(--color-text-secondary);
    margin-bottom: 24px;
}

.about-text {
    font-size: 16px;
    line-height: 1.8;
    color: var(--color-text);
    margin-bottom: 16px;
}

.about-text strong {
    color: var(--color-primary);
}

.about-highlights {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
    margin-top: 32px;
}

.highlight-item {
    display: flex;
    align-items: flex-start;
    gap: 12px;
    padding: 16px;
    background: var(--color-bg);
    border-radius: var(--radius-md);
}

.highlight-icon {
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--color-accent-bg);
    border-radius: var(--radius-sm);
    color: var(--color-accent);
    flex-shrink: 0;
}

.highlight-icon svg {
    width: 20px;
    height: 20px;
}

.highlight-info {
    display: flex;
    flex-direction: column;
}

.highlight-title {
    font-size: 15px;
    font-weight: 600;
    color: var(--color-primary);
}

.highlight-desc {
    font-size: 13px;
    color: var(--color-text-secondary);
}

.about-side {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.about-card {
    padding: 24px;
    border-radius: var(--radius-md);
    border: 1px solid var(--color-border);
}

.about-card-focus {
    background: var(--color-bg);
}

.about-card-mission {
    background: var(--color-primary);
    color: var(--color-white);
    border-color: var(--color-primary);
}

.about-card-mission .about-card-title {
    color: var(--color-white);
}

.about-card-mission .about-card-text {
    color: var(--color-secondary);
}

.about-card-title {
    font-size: 18px;
    font-weight: 600;
    color: var(--color-primary);
    margin-bottom: 16px;
}

.about-card-list {
    list-style: none;
}

.about-card-list li {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 10px 0;
    font-size: 15px;
    color: var(--color-text);
}

.about-card-list li + li {
    border-top: 1px solid var(--color-border);
}

.about-card-text {
    font-size: 15px;
    line-height: 1.6;
}

/* =============================================
   模型介绍
   ============================================= */
.section-models {
    background: var(--color-bg);
}

.models-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 32px;
    margin-bottom: 60px;
}

.model-card {
    background: var(--color-white);
    border-radius: var(--radius-lg);
    padding: 32px;
    border: 1px solid var(--color-border);
    transition: all var(--transition);
    position: relative;
}

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

.model-card-active {
    border-color: var(--color-accent);
    box-shadow: 0 0 0 1px var(--color-accent), var(--shadow-md);
}

.model-card-dev {
    background: linear-gradient(135deg, #F8FAFC, #EEF2FF);
    border-color: var(--color-dev);
}

.model-status {
    margin-bottom: 20px;
}

.status-badge {
    display: inline-block;
    padding: 4px 12px;
    font-size: 13px;
    font-weight: 600;
    border-radius: 20px;
}

.status-badge-active {
    background: rgba(16, 185, 129, 0.15);
    color: #059669;
    border: 1px solid rgba(16, 185, 129, 0.3);
}

.status-badge-dev {
    background: rgba(139, 92, 246, 0.15);
    color: #7C3AED;
    border: 1px solid rgba(139, 92, 246, 0.3);
}

.model-icon {
    width: 64px;
    height: 64px;
    color: var(--color-accent);
    margin-bottom: 20px;
}

.model-card-dev .model-icon {
    color: var(--color-dev);
}

.model-icon svg {
    width: 64px;
    height: 64px;
}

.model-name {
    font-size: 22px;
    font-weight: 700;
    color: var(--color-primary);
    margin-bottom: 12px;
}

.model-desc {
    font-size: 15px;
    line-height: 1.7;
    color: var(--color-text-secondary);
    margin-bottom: 24px;
}

.model-features {
    display: flex;
    flex-direction: column;
    gap: 10px;
    margin-bottom: 28px;
}

.feature {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 14px;
    color: var(--color-text);
}

.feature-icon {
    color: var(--color-success);
    font-weight: 700;
    font-size: 16px;
}

.feature-coming {
    color: var(--color-dev);
}

.feature-coming .feature-icon {
    color: var(--color-dev);
}

.model-card-footer {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding-top: 20px;
    border-top: 1px solid var(--color-border);
}

.model-users {
    font-size: 13px;
    color: var(--color-text-secondary);
}

/* 模型对比 */
.model-comparison {
    background: var(--color-white);
    border-radius: var(--radius-lg);
    padding: 40px;
    border: 1px solid var(--color-border);
}

.comparison-title {
    font-size: 20px;
    font-weight: 600;
    color: var(--color-primary);
    text-align: center;
    margin-bottom: 32px;
}

.comparison-table {
    display: flex;
    flex-direction: column;
}

.comparison-row {
    display: grid;
    grid-template-columns: 140px 1fr 1fr;
    gap: 0;
}

.comparison-row + .comparison-row {
    border-top: 1px solid var(--color-border);
}

.comparison-header {
    background: var(--color-bg);
    font-weight: 600;
}

.comparison-col {
    padding: 16px 20px;
    font-size: 15px;
    display: flex;
    align-items: center;
}

.comparison-col-label {
    color: var(--color-text);
    font-weight: 500;
}

.comparison-col-old {
    color: var(--color-text-secondary);
}

.comparison-col-new {
    color: var(--color-accent);
}

.comparison-highlight {
    font-weight: 600;
}

.comparison-header .comparison-col {
    font-size: 14px;
    color: var(--color-text-secondary);
}

/* =============================================
   模型下载
   ============================================= */
.section-download {
    background: var(--color-white);
}

.download-content {
    text-align: center;
}

.download-info-card {
    background: var(--color-bg);
    border-radius: var(--radius-lg);
    padding: 60px 40px;
    max-width: 700px;
    margin: 0 auto;
    border: 1px solid var(--color-border);
}

.download-icon-large {
    color: var(--color-accent);
    margin-bottom: 24px;
    display: inline-block;
}

.download-icon-large svg {
    width: 80px;
    height: 80px;
}

.download-title {
    font-size: 24px;
    font-weight: 700;
    color: var(--color-primary);
    margin-bottom: 16px;
}

.download-desc {
    font-size: 16px;
    line-height: 1.7;
    color: var(--color-text-secondary);
    margin-bottom: 32px;
}

.download-steps {
    display: flex;
    gap: 24px;
    justify-content: center;
    margin-bottom: 32px;
}

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

.step-number {
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--color-accent);
    color: var(--color-white);
    border-radius: 50%;
    font-size: 14px;
    font-weight: 700;
}

.step-text {
    font-size: 15px;
    color: var(--color-text);
}

.download-notice {
    margin-top: 24px;
    padding: 16px 24px;
    background: rgba(139, 92, 246, 0.08);
    border-radius: var(--radius-md);
    font-size: 15px;
    color: var(--color-text-secondary);
    max-width: 700px;
    margin-left: auto;
    margin-right: auto;
}

/* =============================================
   未来规划 SAAS
   ============================================= */
.section-saas {
    background: var(--color-bg);
}

.saas-roadmap {
    max-width: 700px;
    margin: 0 auto 48px;
    position: relative;
    padding-left: 40px;
}

.saas-roadmap::before {
    content: '';
    position: absolute;
    left: 12px;
    top: 0;
    bottom: 0;
    width: 3px;
    background: var(--color-border);
    border-radius: 3px;
}

.roadmap-item {
    position: relative;
    margin-bottom: 32px;
}

.roadmap-item:last-child {
    margin-bottom: 0;
}

.roadmap-dot {
    position: absolute;
    left: -40px;
    top: 4px;
    width: 24px;
    height: 24px;
    border-radius: 50%;
    border: 3px solid var(--color-border);
    background: var(--color-white);
}

.roadmap-current .roadmap-dot {
    border-color: var(--color-accent);
    background: var(--color-accent);
    box-shadow: 0 0 0 4px var(--color-accent-bg);
}

.roadmap-next .roadmap-dot {
    border-color: var(--color-dev);
    background: var(--color-dev);
    box-shadow: 0 0 0 4px rgba(139, 92, 246, 0.15);
}

.roadmap-future .roadmap-dot {
    border-color: var(--color-secondary);
    background: var(--color-secondary);
}

.roadmap-content {
    background: var(--color-white);
    padding: 24px;
    border-radius: var(--radius-md);
    border: 1px solid var(--color-border);
}

.roadmap-title {
    font-size: 18px;
    font-weight: 700;
    color: var(--color-primary);
    margin-bottom: 8px;
}

.roadmap-desc {
    font-size: 15px;
    color: var(--color-text-secondary);
    margin-bottom: 12px;
}

.roadmap-status {
    display: inline-block;
    font-size: 13px;
    font-weight: 600;
    padding: 4px 12px;
    border-radius: 20px;
}

.roadmap-current .roadmap-status {
    background: rgba(37, 99, 235, 0.1);
    color: #2563EB;
}

.roadmap-next .roadmap-status {
    background: rgba(139, 92, 246, 0.1);
    color: #7C3AED;
}

.roadmap-future .roadmap-status {
    background: rgba(141, 169, 196, 0.2);
    color: var(--color-secondary);
}

.saas-cta {
    background: var(--color-white);
    border-radius: var(--radius-lg);
    padding: 40px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 32px;
    border: 1px solid var(--color-border);
}

.saas-cta-text h3 {
    font-size: 22px;
    font-weight: 700;
    color: var(--color-primary);
    margin-bottom: 8px;
}

.saas-cta-text p {
    font-size: 15px;
    color: var(--color-text-secondary);
}

/* =============================================
   联系我们
   ============================================= */
.section-contact {
    background: var(--color-white);
}

.contact-grid {
    display: grid;
    grid-template-columns: 360px 1fr;
    gap: 40px;
    align-items: start;
}

.contact-info-card {
    background: var(--color-primary);
    color: var(--color-white);
    padding: 32px;
    border-radius: var(--radius-lg);
}

.contact-item {
    display: flex;
    align-items: flex-start;
    gap: 16px;
    padding: 20px 0;
}

.contact-item + .contact-item {
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.contact-icon {
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(255, 255, 255, 0.1);
    border-radius: var(--radius-sm);
    flex-shrink: 0;
}

.contact-icon svg {
    width: 20px;
    height: 20px;
    color: var(--color-secondary);
}

.contact-detail {
    display: flex;
    flex-direction: column;
}

.contact-label {
    font-size: 13px;
    color: var(--color-secondary);
    margin-bottom: 4px;
}

.contact-value {
    font-size: 16px;
    font-weight: 600;
    color: var(--color-white);
}

.contact-message-card {
    background: var(--color-bg);
    padding: 32px;
    border-radius: var(--radius-lg);
    border: 1px solid var(--color-border);
}

.contact-form-title {
    font-size: 20px;
    font-weight: 700;
    color: var(--color-primary);
    margin-bottom: 8px;
}

.contact-form-desc {
    font-size: 14px;
    color: var(--color-text-secondary);
    margin-bottom: 24px;
}

.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    font-size: 14px;
    font-weight: 500;
    color: var(--color-text);
    margin-bottom: 8px;
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 12px 16px;
    font-size: 15px;
    font-family: var(--font-stack);
    color: var(--color-text);
    background: var(--color-white);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    transition: border-color var(--transition);
    outline: none;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    border-color: var(--color-accent);
    box-shadow: 0 0 0 3px var(--color-accent-bg);
}

.form-group textarea {
    resize: vertical;
    min-height: 80px;
}

.contact-form-note {
    font-size: 14px;
    color: var(--color-text-secondary);
    margin-top: 16px;
    text-align: center;
}

.contact-form-note strong {
    color: var(--color-accent);
}

/* =============================================
   页脚
   ============================================= */
.footer {
    background: var(--color-primary);
    color: var(--color-white);
    padding: 60px 0 32px;
}

.footer-grid {
    display: grid;
    grid-template-columns: 280px 1fr 1fr 200px;
    gap: 40px;
    margin-bottom: 40px;
}

.footer-logo {
    display: flex;
    align-items: center;
    gap: 8px;
    text-decoration: none;
    color: var(--color-white);
    font-weight: 700;
    margin-bottom: 12px;
}

.footer-logo .logo-icon {
    background: var(--color-accent);
}

.footer-brand-desc {
    font-size: 14px;
    color: var(--color-secondary);
    margin-bottom: 8px;
}

.footer-brand-company {
    font-size: 14px;
    color: var(--color-secondary);
}

.footer-title {
    font-size: 16px;
    font-weight: 600;
    color: var(--color-white);
    margin-bottom: 16px;
}

.footer-links ul {
    list-style: none;
}

.footer-links li {
    margin-bottom: 8px;
}

.footer-links a {
    font-size: 14px;
    color: var(--color-secondary);
    transition: color var(--transition);
}

.footer-links a:hover {
    color: var(--color-white);
}

.footer-contact p {
    font-size: 14px;
    color: var(--color-secondary);
    margin-bottom: 4px;
}

.footer-bottom {
    padding-top: 24px;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.footer-copyright {
    font-size: 13px;
    color: var(--color-secondary);
}

.footer-copyright a {
    color: var(--color-secondary);
}

.footer-copyright a:hover {
    color: var(--color-white);
}

.footer-icp {
    font-size: 13px;
    color: var(--color-text-light);
}

.footer-icp a {
    color: var(--color-secondary);
    transition: color var(--transition);
}

.footer-icp a:hover {
    color: var(--color-white);
}

/* =============================================
   动画
   ============================================= */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes fadeIn {
    from {
        opacity: 0;
    }
    to {
        opacity: 1;
    }
}

/* 滚动入场动画 */
.animate-on-scroll {
    opacity: 0;
    transform: translateY(40px);
    transition: all 0.6s ease;
}

.animate-on-scroll.visible {
    opacity: 1;
    transform: translateY(0);
}

/* =============================================
   响应式设计
   ============================================= */

/* 平板 (768px - 1024px) */
@media (max-width: 1024px) {
    .about-grid {
        grid-template-columns: 1fr;
        gap: 32px;
    }

    .about-side {
        display: grid;
        grid-template-columns: 1fr 1fr;
    }

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

    .comparison-row {
        grid-template-columns: 120px 1fr 1fr;
    }
}

/* 手机 (<768px) */
@media (max-width: 768px) {
    .nav-menu {
        position: fixed;
        top: 64px;
        left: 0;
        right: 0;
        bottom: 0;
        background: var(--color-white);
        flex-direction: column;
        align-items: stretch;
        padding: 24px;
        gap: 4px;
        transform: translateX(100%);
        transition: transform 0.3s ease;
        z-index: 999;
    }

    .nav-menu.active {
        transform: translateX(0);
    }

    .nav-link {
        padding: 12px 16px;
        font-size: 16px;
    }

    .nav-toggle {
        display: flex;
    }

    .hero-title {
        font-size: 36px;
    }

    .hero-subtitle {
        font-size: 16px;
    }

    .hero-actions {
        flex-direction: column;
        gap: 12px;
    }

    .hero-stats {
        flex-direction: column;
        gap: 16px;
    }

    .section {
        padding: 60px 0;
    }

    .section-title {
        font-size: 28px;
    }

    .section-desc {
        font-size: 15px;
    }

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

    .about-highlights {
        grid-template-columns: 1fr;
    }

    .about-side {
        grid-template-columns: 1fr;
    }

    .download-steps {
        flex-direction: column;
        align-items: center;
        gap: 16px;
    }

    .comparison-row {
        grid-template-columns: 100px 1fr 1fr;
    }

    .comparison-col {
        padding: 12px 10px;
        font-size: 13px;
    }

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

    .saas-cta {
        flex-direction: column;
        text-align: center;
    }

    .footer-grid {
        grid-template-columns: 1fr;
        gap: 24px;
    }

    .footer-bottom {
        flex-direction: column;
        gap: 12px;
        text-align: center;
    }

    .model-comparison {
        padding: 24px;
    }
}

/* 小手机 (<480px) */
@media (max-width: 480px) {
    .hero-title {
        font-size: 28px;
    }

    .stat-number {
        font-size: 28px;
    }

    .hero-content {
        padding: 40px 16px;
    }

    .download-info-card {
        padding: 32px 20px;
    }

    .model-card {
        padding: 24px;
    }

    .container {
        padding: 0 16px;
    }
}

/* =============================================
   Favicon SVG (内联备用)
   ============================================= */