:root {
    --primary: #4361ee;
    --primary-dark: #3a56d4;
    --secondary: #7209b7;
    --accent: #f72585;
    --success: #4cc9f0;
    --dark-bg: #0f172a;
    --dark-card: #1e293b;
    --dark-text: #f1f5f9;
    --light-bg: #f8fafc;
    --light-card: #ffffff;
    --light-text: #334155;
    --gray: #64748b;
    --border-radius: 16px;
    --transition: all 0.3s ease;
    --shadow: 0 10px 25px -5px rgba(0, 0, 0, 0.1);
    --shadow-hover: 0 20px 40px -10px rgba(0, 0, 0, 0.2);
}

.dark-mode {
    --bg: var(--dark-bg);
    --card-bg: var(--dark-card);
    --text: var(--dark-text);
    --heading: #ffffff;
    --border: #334155;
}

.light-mode {
    --bg: var(--light-bg);
    --card-bg: var(--light-card);
    --text: var(--light-text);
    --heading: #1e293b;
    --border: #e2e8f0;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    transition: var(--transition);
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--bg);
    color: var(--text);
    line-height: 1.6;
    overflow-x: hidden;
    padding-top: 80px;
}

.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1.5rem;
}

/* 导航栏样式 */
header {
    position: fixed;
    top: 0;
    width: 100%;
    z-index: 1000;
    background-color: rgba(var(--bg), 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border);
    padding: 0.5rem 0;
}

nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.5rem 0;
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    font-weight: 700;
    font-size: 1.8rem;
    color: var(--heading);
    text-decoration: none;
}

.logo-icon {
    color: var(--primary);
    font-size: 2rem;
}

.nav-links {
    display: flex;
    gap: 2rem;
}

.nav-links a {
    text-decoration: none;
    color: var(--text);
    font-weight: 500;
    position: relative;
    padding: 0.5rem 0;
}

.nav-links a:after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 3px;
    background-color: var(--primary);
    transition: var(--transition);
}

.nav-links a:hover:after {
    width: 100%;
}

.nav-actions {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.theme-toggle {
    background: none;
    border: none;
    cursor: pointer;
    color: var(--text);
    font-size: 1.2rem;
    display: flex;
    align-items: center;
    justify-content: center;
    width: 2.5rem;
    height: 2.5rem;
    border-radius: 50%;
    background-color: var(--card-bg);
}

.btn {
    padding: 0.75rem 1.5rem;
    border-radius: var(--border-radius);
    font-weight: 600;
    cursor: pointer;
    text-decoration: none;
    display: inline-block;
    transition: var(--transition);
    border: none;
    text-align: center;
}

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

.btn-primary:hover {
    background-color: var(--primary-dark);
    transform: translateY(-2px);
    box-shadow: var(--shadow-hover);
}

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

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

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

.btn-accent:hover {
    background-color: #e5127a;
    transform: translateY(-2px);
    box-shadow: var(--shadow-hover);
}

/* Hero部分样式 */
.hero {
    padding: 3rem 0;
    text-align: center;
}

.hero-content {
    max-width: 800px;
    margin: 0 auto;
    padding: 2rem 0;
}

.hero-badge {
    display: inline-block;
    background: linear-gradient(90deg, var(--primary), var(--secondary));
    color: white;
    padding: 0.5rem 1.5rem;
    border-radius: 100px;
    font-size: 0.9rem;
    font-weight: 500;
    margin-bottom: 2rem;
    box-shadow: var(--shadow);
}

h1 {
    font-size: 3.5rem;
    font-weight: 800;
    line-height: 1.2;
    color: var(--heading);
    margin-bottom: 1.5rem;
    background: linear-gradient(90deg, var(--primary), var(--secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.hero-content p {
    font-size: 1.25rem;
    color: var(--gray);
    margin-bottom: 2.5rem;
}

.hero-actions {
    display: flex;
    gap: 1rem;
    justify-content: center;
    margin-bottom: 3rem;
    flex-wrap: wrap;
}

.hero-image {
    position: relative;
    margin-top: 3rem;
    border-radius: var(--border-radius);
    overflow: hidden;
    box-shadow: var(--shadow-hover);
    transform: perspective(1000px) rotateX(5deg);
    transition: transform 0.5s ease;
    border: 1px solid var(--border);
}

.hero-image:hover {
    transform: perspective(1000px) rotateX(0);
}

.hero-image img {
    width: 100%;
    display: block;
}

/* 特性部分样式 */
.features {
    padding: 5rem 0;
}

.section-header {
    text-align: center;
    max-width: 700px;
    margin: 0 auto 4rem;
}

h2 {
    font-size: 2.8rem;
    font-weight: 700;
    color: var(--heading);
    margin-bottom: 1.5rem;
}

.section-header p {
    font-size: 1.2rem;
    color: var(--gray);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.feature-card {
    background-color: var(--card-bg);
    border-radius: var(--border-radius);
    padding: 2.5rem 2rem;
    display: flex;
    flex-direction: column;
    border: 1px solid var(--border);
    transition: var(--transition);
    box-shadow: var(--shadow);
}

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

.feature-icon {
    width: 70px;
    height: 70px;
    border-radius: 20px;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 1.5rem;
    color: white;
    font-size: 2rem;
}

.feature-card h3 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--heading);
}

.feature-card p {
    color: var(--gray);
    margin-bottom: 1.5rem;
}

.feature-link {
    color: var(--primary);
    text-decoration: none;
    font-weight: 500;
    margin-top: auto;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

/* 表单样式 */
.form-container {
    max-width: 500px;
    margin: 2rem auto;
    padding: 2.5rem;
    background-color: var(--card-bg);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    border: 1px solid var(--border);
}

.form-header {
    text-align: center;
    margin-bottom: 2rem;
}

.form-group {
    margin-bottom: 1.5rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
    color: var(--heading);
}

.form-group input {
    width: 100%;
    padding: 1rem;
    border: 1px solid var(--border);
    border-radius: var(--border-radius);
    background-color: var(--bg);
    color: var(--text);
    font-size: 1rem;
}

.form-group input:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(67, 97, 238, 0.2);
}

.form-footer {
    text-align: center;
    margin-top: 2rem;
}

/* 下载页面样式 */
.download-options {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-top: 3rem;
}

.download-card {
    background-color: var(--card-bg);
    border-radius: var(--border-radius);
    padding: 2rem;
    text-align: center;
    border: 1px solid var(--border);
    transition: var(--transition);
    box-shadow: var(--shadow);
}

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

.download-icon {
    font-size: 3rem;
    margin-bottom: 1.5rem;
    color: var(--primary);
}

.download-card h3 {
    font-size: 1.5rem;
    margin-bottom: 1rem;
    color: var(--heading);
}

.download-card p {
    color: var(--gray);
    margin-bottom: 1.5rem;
}

/* CTA部分 */
.cta {
    padding: 6rem 0;
    text-align: center;
    background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
    color: white;
    border-radius: var(--border-radius);
    margin: 4rem 0;
}

.cta-content {
    max-width: 700px;
    margin: 0 auto;
}

.cta h2 {
    color: white;
    margin-bottom: 1.5rem;
}

.cta p {
    font-size: 1.25rem;
    margin-bottom: 2.5rem;
    opacity: 0.9;
}

.cta .btn-outline {
    background-color: transparent;
    color: white;
    border: 2px solid white;
}

.cta .btn-outline:hover {
    background-color: white;
    color: var(--primary);
}

/* 页脚 */
footer {
    padding: 4rem 0 2rem;
    border-top: 1px solid var(--border);
    margin-top: 4rem;
}

.footer-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-bottom: 3rem;
}

.footer-brand h3 {
    font-size: 1.8rem;
    margin-bottom: 1rem;
    color: var(--heading);
}

.footer-brand p {
    color: var(--gray);
    margin-bottom: 1.5rem;
}

.footer-links h4 {
    font-size: 1.2rem;
    margin-bottom: 1.5rem;
    color: var(--heading);
}

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

.footer-links li {
    margin-bottom: 0.75rem;
}

.footer-links a {
    text-decoration: none;
    color: var(--gray);
    transition: var(--transition);
}

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

.social-links {
    display: flex;
    gap: 1rem;
    margin-top: 1.5rem;
}

.social-links a {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background-color: var(--card-bg);
    color: var(--text);
    text-decoration: none;
    transition: var(--transition);
}

.social-links a:hover {
    background-color: var(--primary);
    color: white;
    transform: translateY(-3px);
}

.footer-bottom {
    padding-top: 2rem;
    border-top: 1px solid var(--border);
    text-align: center;
    color: var(--gray);
    font-size: 0.9rem;
}

/* 响应式设计 */
@media (max-width: 900px) {
    .nav-links {
        display: none;
    }

    h1 {
        font-size: 2.8rem;
    }

    h2 {
        font-size: 2.2rem;
    }

    .hero-actions {
        flex-direction: column;
        align-items: center;
    }
}

@media (max-width: 600px) {
    body {
        padding-top: 70px;
    }

    h1 {
        font-size: 2.2rem;
    }

    h2 {
        font-size: 1.8rem;
    }

    .hero-content p {
        font-size: 1.1rem;
    }

    .form-container {
        padding: 1.5rem;
    }
}
/* 表单部分样式 */
.form-section {
    padding: 4rem 0;
    min-height: 70vh;
    display: flex;
    align-items: center;
}

.password-strength {
    margin-top: 0.5rem;
}

.strength-bar {
    height: 5px;
    width: 0%;
    background-color: #e74c3c;
    border-radius: 3px;
    transition: width 0.3s ease, background-color 0.3s ease;
}

.strength-text {
    font-size: 0.8rem;
    margin-top: 0.3rem;
    color: #e74c3c;
}

.checkbox-group {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.checkbox-group input[type="checkbox"] {
    width: auto;
    margin: 0;
}

.checkbox-group label {
    margin: 0;
    font-weight: normal;
}

.form-divider {
    position: relative;
    text-align: center;
    margin: 1.5rem 0;
}

.form-divider:before {
    content: '';
    position: absolute;
    top: 50%;
    left: 0;
    right: 0;
    height: 1px;
    background-color: var(--border);
    z-index: 1;
}

.form-divider span {
    position: relative;
    background-color: var(--card-bg);
    padding: 0 1rem;
    z-index: 2;
    color: var(--gray);
    font-size: 0.9rem;
}

.social-auth {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
    margin-bottom: 1.5rem;
}

.btn-social {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    background-color: var(--card-bg);
    color: var(--text);
    border: 1px solid var(--border);
}

.btn-social:hover {
    background-color: var(--bg);
    transform: translateY(-2px);
}

.google-btn:hover {
    background-color: #DB4437;
    color: white;
    border-color: #DB4437;
}

.github-btn:hover {
    background-color: #333;
    color: white;
    border-color: #333;
}

.forgot-password {
    text-align: right;
    margin-top: 0.5rem;
}

.forgot-password a {
    color: var(--primary);
    text-decoration: none;
    font-size: 0.9rem;
}

.forgot-password a:hover {
    text-decoration: underline;
}

/* 功能详情页面样式 */
.feature-detail {
    padding: 5rem 0;
}

.feature-detail.alt {
    background-color: var(--card-bg);
}

.feature-detail-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
}

.feature-detail-text h2 {
    font-size: 2.5rem;
    margin-bottom: 1.5rem;
}

.feature-detail-text p {
    font-size: 1.1rem;
    margin-bottom: 1.5rem;
    color: var(--gray);
}

.feature-detail-text ul {
    margin-bottom: 2rem;
}

.feature-detail-text li {
    margin-bottom: 0.5rem;
    position: relative;
    padding-left: 1.5rem;
}

.feature-detail-text li:before {
    content: '✓';
    position: absolute;
    left: 0;
    color: var(--primary);
    font-weight: bold;
}

.feature-detail-image {
    border-radius: var(--border-radius);
    overflow: hidden;
    box-shadow: var(--shadow-hover);
}

.feature-detail-image img {
    width: 100%;
    height: auto;
    display: block;
}

.feature-list {
    margin-top: 1rem;
    padding-left: 1.5rem;
}

.feature-list li {
    margin-bottom: 0.5rem;
    color: var(--gray);
}

/* 响应式设计补充 */
@media (max-width: 900px) {
    .feature-detail-content {
        grid-template-columns: 1fr;
        gap: 2rem;
    }
    
    .feature-detail-image {
        order: -1;
    }
    
    .feature-detail-text h2 {
        font-size: 2rem;
    }
}

@media (max-width: 600px) {
    .form-container {
        padding: 1.5rem;
    }
    
    .social-auth {
        flex-direction: column;
    }
}
/* 帮助中心特定样式 */
.help-hero {
    padding: 4rem 0;
    text-align: center;
    background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
    color: white;
}

.help-hero h1 {
    color: white;
    margin-bottom: 2rem;
    -webkit-text-fill-color: white;
}

.search-box {
    position: relative;
    max-width: 600px;
    margin: 0 auto 1.5rem;
}

.search-box input {
    width: 100%;
    padding: 1rem 1.5rem;
    border: none;
    border-radius: 50px;
    font-size: 1.1rem;
    box-shadow: var(--shadow);
}

.search-btn {
    position: absolute;
    right: 10px;
    top: 50%;
    transform: translateY(-50%);
    background: var(--primary);
    border: none;
    color: white;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    cursor: pointer;
}

.help-categories {
    padding: 5rem 0;
}

.categories-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
}

.category-card {
    background-color: var(--card-bg);
    border-radius: var(--border-radius);
    padding: 2rem;
    text-align: center;
    border: 1px solid var(--border);
    transition: var(--transition);
    box-shadow: var(--shadow);
}

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

.category-icon {
    font-size: 3rem;
    margin-bottom: 1.5rem;
    color: var(--primary);
}

.category-card h3 {
    font-size: 1.5rem;
    margin-bottom: 1rem;
    color: var(--heading);
}

.category-card p {
    color: var(--gray);
    margin-bottom: 1.5rem;
}

.faq-section {
    padding: 5rem 0;
    background-color: var(--bg);
}

.faq-container {
    max-width: 800px;
    margin: 0 auto;
}

.faq-item {
    background-color: var(--card-bg);
    border-radius: var(--border-radius);
    margin-bottom: 1rem;
    overflow: hidden;
    border: 1px solid var(--border);
}

.faq-question {
    padding: 1.5rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    cursor: pointer;
    transition: var(--transition);
}

.faq-question:hover {
    background-color: rgba(var(--primary), 0.05);
}

.faq-question h3 {
    font-size: 1.2rem;
    margin: 0;
    color: var(--heading);
}

.faq-answer {
    padding: 0 1.5rem;
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease, padding 0.3s ease;
}

.faq-answer.active {
    max-height: 500px;
    padding: 0 1.5rem 1.5rem;
}

.faq-answer p, .faq-answer ol, .faq-answer ul {
    margin-bottom: 1rem;
}

.faq-answer ol, .faq-answer ul {
    padding-left: 1.5rem;
}

.faq-answer li {
    margin-bottom: 0.5rem;
}

.contact-section {
    padding: 5rem 0;
    background-color: var(--card-bg);
}

.contact-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 3rem;
}

.contact-info h3 {
    margin-bottom: 2rem;
    color: var(--heading);
}

.contact-method {
    display: flex;
    align-items: flex-start;
    margin-bottom: 2rem;
}

.method-icon {
    font-size: 1.5rem;
    color: var(--primary);
    margin-right: 1rem;
    width: 40px;
    text-align: center;
}

.method-details h4 {
    margin: 0 0 0.5rem;
    color: var(--heading);
}

.method-details p {
    margin: 0;
    color: var(--gray);
}

.response-time {
    font-size: 0.9rem;
    color: var(--primary) !important;
    font-weight: 500;
}

.contact-form-container h3 {
    margin-bottom: 1.5rem;
    color: var(--heading);
}

.contact-form-container textarea {
    width: 100%;
    padding: 1rem;
    border: 1px solid var(--border);
    border-radius: var(--border-radius);
    background-color: var(--bg);
    color: var(--text);
    font-size: 1rem;
    font-family: inherit;
    resize: vertical;
}

.contact-form-container select {
    width: 100%;
    padding: 1rem;
    border: 1px solid var(--border);
    border-radius: var(--border-radius);
    background-color: var(--bg);
    color: var(--text);
    font-size: 1rem;
}

.contact-form-container input[type="file"] {
    width: 100%;
    padding: 0.5rem;
    border: 1px dashed var(--border);
    border-radius: var(--border-radius);
    background-color: var(--bg);
}

.contact-form-container small {
    display: block;
    margin-top: 0.5rem;
    color: var(--gray);
}

.resources-section {
    padding: 5rem 0;
}

.resources-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.resource-card {
    background-color: var(--card-bg);
    border-radius: var(--border-radius);
    padding: 2rem;
    text-align: center;
    border: 1px solid var(--border);
    transition: var(--transition);
    box-shadow: var(--shadow);
}

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

.resource-icon {
    font-size: 3rem;
    margin-bottom: 1.5rem;
    color: var(--primary);
}

.resource-card h3 {
    font-size: 1.5rem;
    margin-bottom: 1rem;
    color: var(--heading);
}

.resource-card p {
    color: var(--gray);
    margin-bottom: 1.5rem;
}

/* 响应式设计 */
@media (max-width: 900px) {
    .contact-container {
        grid-template-columns: 1fr;
    }
    
    .categories-grid,
    .resources-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 600px) {
    .help-hero h1 {
        font-size: 2.2rem;
    }
    
    .search-box input {
        padding: 0.8rem 1.2rem;
        font-size: 1rem;
    }
    
    .faq-question {
        padding: 1rem;
    }
    
    .faq-question h3 {
        font-size: 1.1rem;
    }
    
    .faq-answer {
        padding: 0 1rem;
    }
    
    .faq-answer.active {
        padding: 0 1rem 1rem;
    }
}