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

:root {
    --primary-color: #007AFF;
    --secondary-color: #8E8E93;
    --accent-color: #30D158;
    --text-primary: #000000;
    --text-secondary: #6D6D70;
    --background: #FFFFFF;
    --background-secondary: #F2F2F7;
    --border-color: #C6C6C8;
    --shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.12), 0 1px 2px 0 rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 4px 20px 0 rgba(0, 0, 0, 0.1), 0 8px 25px 0 rgba(0, 0, 0, 0.04);
    --ios-blue: #007AFF;
    --ios-green: #30D158;
    --ios-orange: #FF9500;
    --ios-red: #FF3B30;
    --ios-purple: #AF52DE;
}

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

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

/* Navigation */
.navbar {
    position: fixed;
    top: 0;
    width: 100%;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-color);
    z-index: 9999;
    transition: all 0.3s ease;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 70px;
}

.nav-logo h2 {
    color: var(--primary-color);
    font-weight: 700;
    font-size: 1.5rem;
}

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

.nav-link {
    text-decoration: none;
    color: var(--text-primary);
    font-weight: 500;
    transition: color 0.3s ease;
    position: relative;
}

.nav-link:hover {
    color: var(--primary-color);
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background-color: var(--primary-color);
    transition: width 0.3s ease;
}

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

.hamburger {
    display: none;
    flex-direction: column;
    cursor: pointer;
}

.bar {
    width: 25px;
    height: 3px;
    background-color: var(--text-primary);
    margin: 3px 0;
    transition: 0.3s;
}

/* Hero Section */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, #007AFF 0%, #5856D6 100%);
    color: white;
    text-align: center;
    position: relative;
    z-index: 1;
    margin-bottom: 0;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.3);
}

.hero-content {
    position: relative;
    z-index: 1;
    max-width: 800px;
    padding: 0 20px;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    background: linear-gradient(45deg, #fff, #e2e8f0);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: 1.5rem;
    margin-bottom: 1rem;
    color: #e2e8f0;
    font-weight: 500;
}

.hero-description {
    font-size: 1.125rem;
    margin-bottom: 2.5rem;
    color: #cbd5e1;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.hero-buttons {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 12px 24px;
    border-radius: 8px;
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s ease;
    border: 2px solid transparent;
    cursor: pointer;
}

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

.btn-primary:hover {
    background-color: #2563eb;
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn-secondary {
    background-color: transparent;
    color: white;
    border-color: white;
}

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

/* Sections */
section {
    padding: 80px 0;
    position: relative;
    z-index: 1;
}

.section-title {
    text-align: center;
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 3rem;
    color: var(--text-primary);
    position: relative;
}

.section-title::after {
    content: '';
    display: block;
    width: 80px;
    height: 4px;
    background: linear-gradient(45deg, var(--primary-color), var(--accent-color));
    margin: 1rem auto;
    border-radius: 2px;
}

/* About Section */
.about {
    background-color: var(--background-secondary);
    padding: 100px 0;
    overflow: hidden;
}

.about-content {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 4rem;
    align-items: start;
    max-width: 1000px;
    margin: 0 auto;
    position: relative;
    z-index: 1;
}

.about-text {
    padding-right: 2rem;
}

.about-text p {
    font-size: 1.125rem;
    margin-bottom: 1.5rem;
    color: var(--text-secondary);
    line-height: 1.8;
}

.about-stats {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
    min-width: 200px;
    position: relative;
    z-index: 1;
}

.stat {
    text-align: center;
    padding: 2rem 1.5rem;
    background: white;
    border-radius: 16px;
    box-shadow: var(--shadow);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    border: 1px solid var(--border-color);
    position: relative;
    z-index: 2;
}

.stat:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
    z-index: 3;
}

.stat h3 {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: 0.5rem;
}

.stat p {
    color: var(--text-secondary);
    font-weight: 500;
}

/* Skills Section */
.skills {
    padding: 100px 0;
    overflow: hidden;
}

.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 2.5rem;
    max-width: 1000px;
    margin: 0 auto;
    position: relative;
    z-index: 1;
}

.skill-category {
    background: white;
    padding: 2.5rem;
    border-radius: 16px;
    box-shadow: var(--shadow);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    border: 1px solid var(--border-color);
    position: relative;
    overflow: hidden;
    z-index: 2;
}

.skill-category:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
    z-index: 3;
}

.skill-category::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(45deg, var(--ios-blue), var(--ios-green));
}

.skill-category h3 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 1.5rem;
    color: var(--text-primary);
}

.skill-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
}

.skill-tag {
    background: var(--ios-blue);
    color: white;
    padding: 0.5rem 1rem;
    border-radius: 18px;
    font-size: 0.875rem;
    font-weight: 600;
    transition: transform 0.3s ease, background-color 0.3s ease;
    box-shadow: 0 2px 8px rgba(0, 122, 255, 0.25);
}

.skill-tag:hover {
    transform: scale(1.05);
    background: #0056CC;
    box-shadow: 0 4px 12px rgba(0, 122, 255, 0.4);
}

/* Projects Section */
.projects {
    background-color: var(--background-secondary);
    padding: 100px 0;
    overflow: hidden;
}

.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(380px, 1fr));
    gap: 2.5rem;
    max-width: 1200px;
    margin: 0 auto;
    position: relative;
    z-index: 1;
}

.project-card {
    background: white;
    border-radius: 16px;
    overflow: hidden;
    box-shadow: var(--shadow);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    border: 1px solid var(--border-color);
    height: 100%;
    display: flex;
    flex-direction: column;
    position: relative;
    z-index: 2;
}

.project-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-lg);
    z-index: 3;
}

.project-image {
    height: 200px;
    background: linear-gradient(45deg, var(--ios-blue), var(--ios-purple));
    display: flex;
    align-items: center;
    justify-content: center;
}

.project-placeholder {
    color: white;
    font-size: 3rem;
    font-weight: 600;
}

.project-content {
    padding: 2rem;
    flex: 1;
    display: flex;
    flex-direction: column;
}

.project-content h3 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 0.75rem;
    color: var(--text-primary);
}

.project-content p {
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
    line-height: 1.7;
    flex: 1;
}

.project-tech {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-bottom: 1rem;
}

.project-tech span {
    background-color: var(--background-secondary);
    color: var(--text-secondary);
    padding: 0.25rem 0.75rem;
    border-radius: 12px;
    font-size: 0.875rem;
}

.project-links {
    display: flex;
    gap: 1rem;
}

.project-link {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s ease;
}

.project-link:hover {
    color: var(--accent-color);
}

/* Contact Section */
.contact {
    padding: 100px 0;
    overflow: hidden;
}

.contact-content {
    display: flex;
    justify-content: center;
    align-items: center;
    max-width: 800px;
    margin: 0 auto;
    position: relative;
    z-index: 1;
}

.contact-info {
    text-align: center;
    width: 100%;
}

.contact-info h3 {
    font-size: 2rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.contact-info p {
    color: var(--text-secondary);
    margin-bottom: 2.5rem;
    line-height: 1.8;
    font-size: 1.125rem;
}

.contact-methods {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 2rem;
    margin-top: 3rem;
}

.contact-method {
    background: white;
    padding: 2rem;
    border-radius: 16px;
    box-shadow: var(--shadow);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    text-align: center;
    border: 1px solid var(--border-color);
    position: relative;
    overflow: hidden;
    z-index: 2;
}

.contact-method:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
    z-index: 3;
}

.contact-method::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: linear-gradient(45deg, var(--ios-blue), var(--ios-green));
}

.contact-method strong {
    display: block;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
    font-size: 1rem;
}

.contact-method span {
    color: var(--primary-color);
    font-weight: 500;
}

/* Footer */
.footer {
    background-color: var(--text-primary);
    color: white;
    padding: 2rem 0;
}

.footer-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1rem;
}

.footer-content p {
    margin: 0;
    color: #cbd5e1;
}

.footer-links {
    display: flex;
    align-items: center;
    gap: 1rem;
    flex-wrap: wrap;
    justify-content: center;
}

.footer-links a {
    color: #94a3b8;
    text-decoration: none;
    font-size: 0.875rem;
    transition: color 0.3s ease;
    display: flex;
    align-items: center;
    gap: 0.25rem;
}

.footer-links a:hover {
    color: #e2e8f0;
}

.divider {
    color: #64748b;
    font-size: 0.875rem;
}

.beian-icon {
    width: 14px;
    height: 14px;
    opacity: 0.7;
}

/* Mobile Responsive */
@media screen and (max-width: 768px) {
    .nav-menu {
        position: fixed;
        left: -100%;
        top: 70px;
        flex-direction: column;
        background-color: white;
        width: 100%;
        text-align: center;
        transition: 0.3s;
        box-shadow: var(--shadow);
        padding: 2rem 0;
    }

    .nav-menu.active {
        left: 0;
    }

    .hamburger {
        display: flex;
    }

    .hamburger.active .bar:nth-child(2) {
        opacity: 0;
    }

    .hamburger.active .bar:nth-child(1) {
        transform: translateY(8px) rotate(45deg);
    }

    .hamburger.active .bar:nth-child(3) {
        transform: translateY(-8px) rotate(-45deg);
    }

    .hero-title {
        font-size: 2.5rem;
    }

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

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

    .about-content {
        grid-template-columns: 1fr;
        gap: 3rem;
        text-align: center;
    }
    
    .about-text {
        padding-right: 0;
    }

    .about-stats {
        flex-direction: row;
        justify-content: space-between;
        gap: 1rem;
    }
    
    .stat {
        flex: 1;
        min-width: auto;
        padding: 1.5rem 1rem;
    }

    .contact-methods {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }
    
    .contact-method {
        padding: 1.5rem;
    }

    .section-title {
        font-size: 2rem;
    }

    .footer-links {
        flex-direction: column;
        gap: 0.5rem;
    }
}

@media screen and (max-width: 480px) {
    .container {
        padding: 0 15px;
    }

    .hero-title {
        font-size: 2rem;
    }

    .skills-grid,
    .projects-grid {
        grid-template-columns: 1fr;
        gap: 2rem;
    }

    .about-stats {
        flex-direction: column;
        gap: 1.5rem;
    }
    
    .stat {
        padding: 2rem 1.5rem;
    }
}