/* AI前线 - 大厂风格样式 */

/* CSS Variables */
:root {
    --primary-color: #2563eb;
    --primary-hover: #1d4ed8;
    --secondary-color: #7c3aed;
    --accent-color: #06b6d4;
    --text-primary: #1f2937;
    --text-secondary: #6b7280;
    --text-light: #9ca3af;
    --bg-primary: #ffffff;
    --bg-secondary: #f9fafb;
    --bg-tertiary: #f3f4f6;
    --border-color: #e5e7eb;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --radius-sm: 6px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --radius-xl: 16px;
    --max-width: 1200px;
    --header-height: 64px;
}

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

html {
    scroll-behavior: smooth;
}

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

a {
    color: var(--primary-color);
    text-decoration: none;
    transition: color 0.2s ease;
}

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

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

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

/* Header */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: var(--header-height);
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-color);
    z-index: 1000;
}

.nav {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 100%;
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 24px;
}

.nav-brand a {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--text-primary);
    display: flex;
    align-items: center;
    gap: 8px;
}

.nav-brand svg {
    width: 28px;
    height: 28px;
    color: var(--primary-color);
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 32px;
}

.nav-menu a {
    color: var(--text-secondary);
    font-weight: 500;
    font-size: 0.9375rem;
    padding: 8px 0;
    position: relative;
}

.nav-menu a:hover,
.nav-menu a.active {
    color: var(--primary-color);
}

.nav-menu a.active::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    height: 2px;
    background: var(--primary-color);
    border-radius: 2px;
}

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

.nav-toggle span {
    display: block;
    width: 24px;
    height: 2px;
    background: var(--text-primary);
    border-radius: 2px;
    transition: all 0.3s ease;
}

/* Main Content */
main {
    margin-top: var(--header-height);
    min-height: calc(100vh - var(--header-height) - 300px);
}

/* Hero Section */
.hero {
    padding: 80px 0;
    background: linear-gradient(135deg, #f0f9ff 0%, #f5f3ff 50%, #fdf2f8 100%);
}

.hero .container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: center;
}

.hero-content h1 {
    font-size: 3rem;
    font-weight: 800;
    line-height: 1.2;
    margin-bottom: 16px;
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: 1.5rem;
    color: var(--text-secondary);
    margin-bottom: 20px;
    font-weight: 500;
}

.hero-description {
    font-size: 1.125rem;
    color: var(--text-secondary);
    margin-bottom: 32px;
    line-height: 1.7;
}

.hero-buttons {
    display: flex;
    gap: 16px;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 12px 28px;
    font-size: 0.9375rem;
    font-weight: 600;
    border-radius: var(--radius-md);
    border: none;
    cursor: pointer;
    transition: all 0.2s ease;
}

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

.btn-primary:hover {
    background: var(--primary-hover);
    color: white;
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

.btn-secondary {
    background: white;
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

.btn-secondary:hover {
    background: var(--bg-secondary);
    color: var(--text-primary);
}

.btn-outline {
    background: transparent;
    color: var(--primary-color);
    border: 1px solid var(--primary-color);
}

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

/* Code Window */
.code-window {
    background: #1e293b;
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow-lg);
}

.code-header {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 12px 16px;
    background: #0f172a;
    border-bottom: 1px solid #334155;
}

.dot {
    width: 12px;
    height: 12px;
    border-radius: 50%;
}

.dot.red { background: #ef4444; }
.dot.yellow { background: #f59e0b; }
.dot.green { background: #22c55e; }

.filename {
    margin-left: 8px;
    color: #94a3b8;
    font-size: 0.875rem;
}

.code-content {
    padding: 20px;
    margin: 0;
    font-family: 'Fira Code', 'Consolas', monospace;
    font-size: 0.875rem;
    line-height: 1.6;
    color: #e2e8f0;
    overflow-x: auto;
}

.code-content .keyword { color: #c084fc; }
.code-content .property { color: #93c5fd; }
.code-content .string { color: #86efac; }

/* Section Titles */
.section-title {
    font-size: 1.875rem;
    font-weight: 700;
    text-align: center;
    margin-bottom: 48px;
    color: var(--text-primary);
}

/* Skills Section */
.skills {
    padding: 80px 0;
    background: var(--bg-primary);
}

.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 24px;
}

.skill-item {
    background: var(--bg-secondary);
    padding: 32px 24px;
    border-radius: var(--radius-lg);
    text-align: center;
    transition: all 0.3s ease;
    border: 1px solid var(--border-color);
}

.skill-item:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary-color);
}

.skill-icon {
    width: 64px;
    height: 64px;
    margin: 0 auto 20px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, rgba(37, 99, 235, 0.1) 0%, rgba(124, 58, 237, 0.1) 100%);
    border-radius: 16px;
}

.skill-icon svg {
    width: 32px;
    height: 32px;
    color: var(--primary-color);
}

.skill-item h4 {
    font-size: 1.125rem;
    font-weight: 600;
    margin-bottom: 8px;
    color: var(--text-primary);
}

.skill-item p {
    color: var(--text-secondary);
    font-size: 0.9375rem;
}

/* Featured Section */
.featured {
    padding: 80px 0;
    background: var(--bg-secondary);
}

.articles-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 24px;
}

.article-card {
    background: white;
    padding: 28px;
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-color);
    transition: all 0.3s ease;
}

.article-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary-color);
}

.article-meta {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 12px;
}

.category {
    display: inline-flex;
    align-items: center;
    padding: 4px 12px;
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    color: white;
    font-size: 0.75rem;
    font-weight: 600;
    border-radius: 20px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.article-meta time {
    color: var(--text-light);
    font-size: 0.875rem;
}

.article-card h3 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 12px;
    line-height: 1.4;
}

.article-card h3 a {
    color: var(--text-primary);
}

.article-card h3 a:hover {
    color: var(--primary-color);
}

.article-card p {
    color: var(--text-secondary);
    font-size: 0.9375rem;
    line-height: 1.6;
    margin-bottom: 16px;
}

.read-more {
    font-weight: 600;
    font-size: 0.9375rem;
}

/* Projects Preview */
.projects-preview {
    padding: 80px 0;
    background: var(--bg-primary);
}

.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 24px;
}

.project-card {
    background: white;
    border-radius: var(--radius-lg);
    overflow: hidden;
    border: 1px solid var(--border-color);
    transition: all 0.3s ease;
}

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

.project-image {
    height: 160px;
    display: flex;
    align-items: flex-start;
    justify-content: flex-end;
    padding: 16px;
}

.project-tag {
    background: rgba(255, 255, 255, 0.95);
    color: var(--text-primary);
    padding: 4px 12px;
    border-radius: 20px;
    font-size: 0.75rem;
    font-weight: 600;
}

.project-info {
    padding: 24px;
}

.project-info h3 {
    font-size: 1.125rem;
    font-weight: 600;
    margin-bottom: 8px;
    color: var(--text-primary);
}

.project-info p {
    color: var(--text-secondary);
    font-size: 0.9375rem;
    line-height: 1.6;
    margin-bottom: 16px;
}

.project-tech {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-bottom: 16px;
}

.project-tech span {
    background: var(--bg-tertiary);
    color: var(--text-secondary);
    padding: 4px 10px;
    border-radius: 4px;
    font-size: 0.75rem;
    font-weight: 500;
}

/* Center */
.center {
    text-align: center;
}

/* Footer */
.footer {
    background: #0f172a;
    color: #94a3b8;
    padding: 60px 0 24px;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 40px;
    margin-bottom: 40px;
}

.footer-section h4 {
    color: white;
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 16px;
}

.footer-section p {
    font-size: 0.9375rem;
    line-height: 1.6;
}

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

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

.footer-section a {
    color: #94a3b8;
    font-size: 0.9375rem;
}

.footer-section a:hover {
    color: white;
}

.footer-bottom {
    border-top: 1px solid #1e293b;
    padding-top: 24px;
    text-align: center;
    font-size: 0.875rem;
}

.footer-bottom a {
    color: #94a3b8;
}

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

/* Page Header */
.page-header {
    padding: 60px 0;
    background: linear-gradient(135deg, #f0f9ff 0%, #f5f3ff 50%, #fdf2f8 100%);
    text-align: center;
}

.page-header h1 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 12px;
    color: var(--text-primary);
}

.page-header p {
    font-size: 1.125rem;
    color: var(--text-secondary);
}

/* About Section */
.about-section {
    padding: 60px 0;
}

.about-content {
    max-width: 800px;
    margin: 0 auto;
}

.about-image {
    width: 120px;
    height: 120px;
    margin: 0 auto 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    border-radius: 50%;
}

.about-image svg {
    width: 60px;
    height: 60px;
    color: white;
}

.about-text h2 {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 16px;
    color: var(--text-primary);
}

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

.about-text ul {
    color: var(--text-secondary);
    line-height: 2;
    margin-left: 20px;
    margin-bottom: 24px;
}

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

/* Timeline */
.timeline {
    position: relative;
    padding-left: 24px;
    border-left: 2px solid var(--border-color);
}

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

.timeline-item::before {
    content: '';
    position: absolute;
    left: -29px;
    top: 4px;
    width: 12px;
    height: 12px;
    background: var(--primary-color);
    border-radius: 50%;
    border: 2px solid white;
    box-shadow: 0 0 0 2px var(--primary-color);
}

.timeline-date {
    display: inline-block;
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--primary-color);
    margin-bottom: 4px;
}

.timeline-content h4 {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 4px;
}

.timeline-content p {
    color: var(--text-secondary);
    font-size: 0.9375rem;
}

/* Contact Section */
.contact-section {
    padding: 60px 0;
}

.contact-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 48px;
    max-width: 900px;
    margin: 0 auto;
}

.contact-info h3 {
    font-size: 1.25rem;
    font-weight: 700;
    margin-bottom: 24px;
    color: var(--text-primary);
}

.contact-item {
    display: flex;
    align-items: center;
    gap: 16px;
    margin-bottom: 20px;
}

.contact-icon {
    width: 48px;
    height: 48px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    border-radius: 12px;
    color: white;
    flex-shrink: 0;
}

.contact-icon svg {
    width: 24px;
    height: 24px;
}

.contact-item h4 {
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--text-secondary);
    margin-bottom: 4px;
}

.contact-item p {
    font-size: 1rem;
    color: var(--text-primary);
    font-weight: 500;
}

/* Contact Form */
.contact-form-wrapper {
    background: var(--bg-secondary);
    padding: 32px;
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-color);
}

.contact-form h3 {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--text-primary);
}

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

.form-group label {
    display: block;
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-primary);
    margin-bottom: 6px;
}

.form-group input,
.form-group textarea,
.form-group select {
    width: 100%;
    padding: 12px 16px;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    font-size: 0.9375rem;
    font-family: inherit;
    background: white;
    transition: border-color 0.2s ease;
}

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
    outline: none;
    border-color: var(--primary-color);
}

.form-group textarea {
    min-height: 120px;
    resize: vertical;
}

/* Article Content */
.article-content {
    padding: 40px 0 80px;
}

.article-body {
    max-width: 720px;
    margin: 0 auto;
}

.article-body p {
    font-size: 1.0625rem;
    line-height: 1.8;
    color: var(--text-secondary);
    margin-bottom: 20px;
}

.article-body h2 {
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--text-primary);
    margin: 48px 0 20px;
    padding-bottom: 12px;
    border-bottom: 2px solid var(--border-color);
}

.article-body h3 {
    font-size: 1.375rem;
    font-weight: 600;
    color: var(--text-primary);
    margin: 32px 0 16px;
}

.article-body ul,
.article-body ol {
    margin-bottom: 20px;
    padding-left: 24px;
}

.article-body li {
    margin-bottom: 8px;
    color: var(--text-secondary);
    line-height: 1.7;
}

.article-body strong {
    color: var(--text-primary);
    font-weight: 600;
}

.article-body pre {
    background: #1e293b;
    color: #e2e8f0;
    padding: 20px;
    border-radius: var(--radius-md);
    overflow-x: auto;
    margin-bottom: 20px;
    font-family: 'Fira Code', 'Consolas', monospace;
    font-size: 0.875rem;
    line-height: 1.6;
}

.article-body code {
    background: var(--bg-tertiary);
    padding: 2px 6px;
    border-radius: 4px;
    font-family: 'Fira Code', 'Consolas', monospace;
    font-size: 0.875em;
    color: var(--primary-color);
}

.article-body pre code {
    background: none;
    padding: 0;
    color: inherit;
}

/* Responsive */
@media (max-width: 768px) {
    .nav-menu {
        display: none;
        position: absolute;
        top: var(--header-height);
        left: 0;
        right: 0;
        background: white;
        flex-direction: column;
        padding: 16px 24px;
        border-bottom: 1px solid var(--border-color);
        gap: 0;
    }

    .nav-menu.active {
        display: flex;
    }

    .nav-menu li {
        border-bottom: 1px solid var(--border-color);
    }

    .nav-menu li:last-child {
        border-bottom: none;
    }

    .nav-menu a {
        display: block;
        padding: 12px 0;
    }

    .nav-menu a.active::after {
        display: none;
    }

    .nav-toggle {
        display: flex;
    }

    .hero .container {
        grid-template-columns: 1fr;
        gap: 40px;
    }

    .hero-content h1 {
        font-size: 2rem;
    }

    .hero-subtitle {
        font-size: 1.25rem;
    }

    .hero-buttons {
        flex-direction: column;
    }

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

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

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

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

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

    .page-header h1 {
        font-size: 1.875rem;
    }
}

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