/* Global Styles & Variables */
:root {
    /* Colors */
    --primary: #6366f1;
    --primary-dark: #4f46e5;
    --primary-light: #818cf8;
    --secondary: #14b8a6;
    --accent: #f43f5e;
    --white: #ffffff;
    --light: #f8fafc;
    --dark: #0f172a;
    --gray-100: #f1f5f9;
    --gray-200: #e2e8f0;
    --gray-300: #cbd5e1;
    --gray-400: #94a3b8;
    --gray-500: #64748b;
    --gray-600: #475569;
    --gray-700: #334155;
    --gray-800: #1e293b;
    --gray-900: #0f172a;
    
    /* Typography */
    --font-sans: 'Inter', sans-serif;
    --font-display: 'Playfair Display', serif;
    
    /* Spacing */
    --space-xs: 0.25rem;
    --space-sm: 0.5rem;
    --space-md: 1rem;
    --space-lg: 1.5rem;
    --space-xl: 2rem;
    --space-2xl: 3rem;
    --space-3xl: 4rem;
    
    /* Transitions */
    --transition-fast: 0.2s ease;
    --transition-normal: 0.3s ease;
    --transition-slow: 0.5s ease;
    
    /* Shadows */
    --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);
    
    /* Border radius */
    --radius-sm: 0.25rem;
    --radius-md: 0.5rem;
    --radius-lg: 1rem;
    --radius-full: 9999px;
}

/* Theme colors */
:root[data-theme="light"] {
    --bg-primary: var(--white);
    --bg-secondary: var(--gray-100);
    --bg-tertiary: var(--gray-200);
    --text-primary: var(--gray-900);
    --text-secondary: var(--gray-700);
    --text-tertiary: var(--gray-500);
    --border-color: var(--gray-200);
    --card-bg: var(--white);
    --card-shadow: var(--shadow-md);
}

:root[data-theme="dark"] {
    --bg-primary: var(--gray-900);
    --bg-secondary: var(--gray-800);
    --bg-tertiary: var(--gray-700);
    --text-primary: var(--gray-100);
    --text-secondary: var(--gray-300);
    --text-tertiary: var(--gray-400);
    --border-color: var(--gray-700);
    --card-bg: var(--gray-800);
    --card-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.2), 0 2px 4px -1px rgba(0, 0, 0, 0.1);
}

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

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    font-family: var(--font-sans);
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    transition: background-color var(--transition-normal), color var(--transition-normal);
}

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

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

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

button {
    border: none;
    background: none;
    font: inherit;
    cursor: pointer;
}

ul, ol {
    list-style: none;
}

/* Layout */
.page-wrapper {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--space-lg);
}

.section {
    padding: var(--space-3xl) 0;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    line-height: 1.2;
    margin-bottom: var(--space-md);
}

h1 {
    font-size: 2.5rem;
}

h2 {
    font-size: 2rem;
}

h3 {
    font-size: 1.75rem;
}

h4 {
    font-size: 1.5rem;
}

p {
    margin-bottom: var(--space-md);
}

.lead {
    font-size: 1.125rem;
    font-weight: 500;
}

/* Buttons */
.btn {
    display: inline-block;
    padding: var(--space-sm) var(--space-lg);
    border-radius: var(--radius-md);
    font-weight: 500;
    text-align: center;
    transition: all var(--transition-fast);
}

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

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

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

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

.btn-sm {
    padding: var(--space-xs) var(--space-md);
    font-size: 0.875rem;
}

.btn-block {
    display: block;
    width: 100%;
}

/* Header & Navigation */
.header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background-color: var(--bg-primary);
    box-shadow: var(--shadow-sm);
    z-index: 100;
    transition: background-color var(--transition-normal);
}

.header-inner {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 70px;
}

.logo {
    font-family: var(--font-display);
    font-size: 2rem;
    font-weight: 700;
    color: var(--text-primary);
}

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

.nav-desktop {
    display: none;
}

.nav-links {
    display: flex;
    gap: var(--space-lg);
}

.nav-link {
    color: var(--text-secondary);
    font-weight: 500;
    transition: color var(--transition-fast);
}

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

.header-actions {
    display: flex;
    align-items: center;
    gap: var(--space-md);
}

.theme-toggle {
    font-size: 1.25rem;
    color: var(--text-secondary);
    transition: color var(--transition-fast);
}

.theme-toggle:hover {
    color: var(--primary);
}

/* Light mode / dark mode icons */
.fa-sun {
    display: none;
}

.fa-moon {
    display: block;
}

:root[data-theme="dark"] .fa-sun {
    display: block;
}

:root[data-theme="dark"] .fa-moon {
    display: none;
}

/* Mobile menu */
.mobile-menu-toggle {
    display: flex;
    flex-direction: column;
    gap: 5px;
    width: 24px;
    height: 18px;
}

.mobile-menu-toggle span {
    display: block;
    width: 100%;
    height: 2px;
    background-color: var(--text-primary);
    transition: transform var(--transition-fast), opacity var(--transition-fast);
}

.mobile-menu-toggle.active span:nth-child(1) {
    transform: translateY(8px) rotate(45deg);
}

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

.mobile-menu-toggle.active span:nth-child(3) {
    transform: translateY(-8px) rotate(-45deg);
}

.nav-mobile {
    display: none;
    background-color: var(--bg-primary);
    padding: var(--space-lg);
    border-top: 1px solid var(--border-color);
}

.nav-mobile.active {
    display: block;
}

.mobile-nav-links {
    display: flex;
    flex-direction: column;
    gap: var(--space-md);
}

.mobile-nav-link {
    color: var(--text-secondary);
    font-weight: 500;
    font-size: 1.125rem;
    padding: var(--space-sm) 0;
}

/* Hero Section */
.hero {
    padding: var(--space-3xl) 0;
    min-height: 100vh;
    display: flex;
    align-items: center;
    position: relative;
}

.hero .container {
    display: flex;
    flex-direction: column;
    gap: var(--space-2xl);
}

.hero-content {
    max-width: 600px;
}

.hero-title {
    font-family: var(--font-display);
    margin-bottom: var(--space-md);
}

.greeting {
    display: block;
    font-size: 1.5rem;
    color: var(--text-secondary);
}

.name {
    display: block;
    font-size: 3.5rem;
    color: var(--primary);
}

.hero-subtitle {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: var(--space-md);
    background: linear-gradient(
        to right,
        #4285F4, /* Google Blue */
        #EA4335, /* Google Red */
        #FBBC05, /* Google Yellow */
        #34A853  /* Google Green */
    );
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
    display: inline-block;
}

.hero-description {
    font-size: 1.125rem;
    color: var(--text-secondary);
    margin-bottom: var(--space-lg);
}

.hero-actions {
    display: flex;
    gap: var(--space-md);
    flex-wrap: wrap;
}

.hero-image {
    position: relative;
    margin-top: var(--space-2xl);
}

.blob-animation {
    width: 300px;
    height: 300px;
    background-color: var(--primary-light);
    opacity: 0.1;
    border-radius: 60% 40% 30% 70% / 60% 30% 70% 40%;
    animation: blob-animation 8s ease-in-out infinite;
}

@keyframes blob-animation {
    0% {
        border-radius: 60% 40% 30% 70% / 60% 30% 70% 40%;
    }
    50% {
        border-radius: 40% 60% 70% 30% / 30% 60% 40% 70%;
    }
    100% {
        border-radius: 60% 40% 30% 70% / 60% 30% 70% 40%;
    }
}

.tech-icons {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
}

.tech-icon {
    position: absolute;
    display: flex;
    align-items: center;
    justify-content: center;
    width: 50px;
    height: 50px;
    border-radius: var(--radius-full);
    background-color: var(--card-bg);
    box-shadow: var(--shadow-md);
    font-size: 1.5rem;
    color: var(--primary);
    animation: float 5s ease-in-out infinite;
}

.tech-icon.python {
    top: 20%;
    left: 20%;
    animation-delay: 0s;
}

.tech-icon.js {
    top: 30%;
    right: 20%;
    animation-delay: 1s;
}

.tech-icon.html {
    bottom: 30%;
    left: 10%;
    animation-delay: 1.5s;
}

.tech-icon.css {
    bottom: 20%;
    right: 30%;
    animation-delay: 0.5s;
}

.tech-icon.cpp {
    top: 50%;
    left: 50%;
    animation-delay: 2s;
    font-family: var(--font-sans);
    font-weight: 700;
    font-size: 0.875rem;
}

@keyframes float {
    0% {
        transform: translateY(0);
    }
    50% {
        transform: translateY(-10px);
    }
    100% {
        transform: translateY(0);
    }
}

/* Scroll indicator */
.scroll-indicator {
    position: absolute;
    bottom: var(--space-2xl);
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--space-sm);
}

.mouse {
    width: 30px;
    height: 50px;
    border: 2px solid var(--text-secondary);
    border-radius: var(--radius-full);
    position: relative;
}

.wheel {
    width: 6px;
    height: 6px;
    background-color: var(--text-secondary);
    border-radius: var(--radius-full);
    position: absolute;
    top: 10px;
    left: 50%;
    transform: translateX(-50%);
    animation: scroll 1.5s infinite;
}

@keyframes scroll {
    0% {
        opacity: 1;
        transform: translateX(-50%) translateY(0);
    }
    100% {
        opacity: 0;
        transform: translateX(-50%) translateY(20px);
    }
}

.arrow {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 5px;
}

.arrow span {
    display: block;
    width: 10px;
    height: 10px;
    border-bottom: 2px solid var(--text-secondary);
    border-right: 2px solid var(--text-secondary);
    transform: rotate(45deg);
    animation: arrow 1.5s infinite;
}

.arrow span:nth-child(2) {
    animation-delay: 0.2s;
}

.arrow span:nth-child(3) {
    animation-delay: 0.4s;
}

@keyframes arrow {
    0% {
        opacity: 0;
    }
    50% {
        opacity: 1;
    }
    100% {
        opacity: 0;
    }
}

/* Section Headers */
.section-header {
    text-align: center;
    margin-bottom: var(--space-2xl);
}

.section-tag {
    display: inline-block;
    padding: var(--space-xs) var(--space-md);
    background-color: var(--primary-dark);
    color: var(--light);
    border-radius: var(--radius-full);
    font-size: 0.875rem;
    font-weight: 500;
    margin-bottom: var(--space-sm);
}

.section-title {
    font-family: var(--font-display);
    font-size: 2.5rem;
    color: var(--text-primary);
}

/* About Section */
.about-content {
    display: flex;
    flex-direction: column;
    gap: var(--space-2xl);
}

.about-stats {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-lg);
    margin-top: var(--space-lg);
}

.stat {
    flex: 1;
    min-width: 120px;
}

.stat-number {
    display: block;
    font-size: 2rem;
    font-weight: 700;
    color: var(--primary);
}

.stat-label {
    font-size: 0.875rem;
    color: var(--text-secondary);
}

.about-visual {
    font-family: 'Monaco', 'Consolas', monospace;
}

.code-snippet {
    border-radius: 6px;
    overflow: hidden;
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.2);
}

/* Code Header */
.code-header {
    background-color: #1e2432;
    padding: 10px 15px;
    display: flex;
    align-items: center;
}

.dot {
    width: 12px;
    height: 12px;
    border-radius: 50%;
    margin-right: 6px;
}

.red { background-color: #ff5f56; }
.yellow { background-color: #ffbd2e; }
.green { background-color: #27c93f; }

.file-name {
    color: #8c96a5;
    margin-left: 10px;
    font-size: 14px;
}

/* Code Section */
pre {
    margin: 0;
    background-color: #1e2432 !important;
}

code.language-python {
    background-color: #1e2432 !important;
    color: #c3c8d1;
    font-family: 'Monaco', 'Consolas', monospace;
    padding: 15px !important;
    display: block;
    tab-size: 4;
}

/* Python Highlight */
.language-python .token.keyword { color: #c678dd; }  /* class, def 等关键字 */
.language-python .token.function { color: #61afef; }  /* 函数名 */
.language-python .token.string { color: #98c379; }  /* 字符串 */
.language-python .token.comment { color: #5c6370; }  /* 注释 */
.language-python .token.property { color: #e06c75; }  /* self.xxx 中的 xxx */
.language-python .token.operator { color: #56b6c2; }  /* =, +, - 等操作符 */

/* Skills Section */
.skills-content {
    display: flex;
    flex-direction: column;
    gap: var(--space-2xl);
}

.skill-category {
    background-color: var(--card-bg);
    border-radius: var(--radius-md);
    box-shadow: var(--card-shadow);
    padding: var(--space-lg);
    transition: transform var(--transition-normal), box-shadow var(--transition-normal);
}

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

.category-title {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    margin-bottom: var(--space-lg);
    color: var(--primary);
}

.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: var(--space-lg);
}

.skill-card {
    display: flex;
    align-items: center;
    gap: var(--space-md);
}

.skill-icon {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    color: var(--primary-dark);
    border-radius: var(--radius-md);
    font-size: 1.25rem;
}

.skill-icon.c-plus {
    font-family: var(--font-sans);
    font-weight: 700;
    font-size: 0.875rem;
}

.skill-info {
    flex: 1;
}

.skill-name {
    font-size: 1rem;
    margin-bottom: var(--space-xs);
}

.skill-bar {
    height: 6px;
    background-color: var(--bg-tertiary);
    border-radius: var(--radius-full);
    overflow: hidden;
}

.skill-progress {
    height: 100%;
    background-color: var(--primary);
    border-radius: var(--radius-full);
}

/* Projects Section */
.projects-filters {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: var(--space-md);
    margin-bottom: var(--space-2xl);
}

.filter-btn {
    padding: var(--space-xs) var(--space-md);
    border-radius: var(--radius-full);
    color: var(--text-secondary);
    font-weight: 500;
    transition: all var(--transition-fast);
}

.filter-btn:hover, .filter-btn.active {
    background-color: var(--primary);
    color: var(--white);
}

.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: var(--space-lg);
}

.project-card {
    background-color: var(--card-bg);
    border-radius: var(--radius-md);
    overflow: hidden;
    box-shadow: var(--card-shadow);
    transition: transform var(--transition-normal), box-shadow var(--transition-normal);
}

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

.project-image {
    position: relative;
    height: 200px;
    overflow: hidden;
}

.project-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform var(--transition-normal);
}

.project-card:hover .project-image img {
    transform: scale(1.05);
}

.project-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    transition: opacity var(--transition-normal);
}

.project-card:hover .project-overlay {
    opacity: 1;
}

.project-link {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 50px;
    height: 50px;
    background-color: var(--white);
    border-radius: var(--radius-full);
    color: var(--dark);
    font-size: 1.25rem;
    transition: all var(--transition-fast);
}

.project-link:hover {
    background-color: var(--primary);
    color: var(--white);
}

.project-content {
    padding: var(--space-lg);
}

.project-tags {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-xs);
    margin-bottom: var(--space-md);
}

.project-tag {
    padding: 2px var(--space-sm);
    background-color: var(--bg-secondary);
    border-radius: var(--radius-sm);
    font-size: 0.75rem;
    color: var(--text-secondary);
}

.project-title {
    font-size: 1.25rem;
    margin-bottom: var(--space-sm);
}

.project-description {
    color: var(--text-secondary);
    font-size: 0.875rem;
    margin-bottom: var(--space-md);
}

/* Contact Section */
.contact-content {
    display: flex;
    flex-direction: column;
    gap: var(--space-2xl);
}

.contact-info h3 {
    color: var(--primary);
    margin-bottom: var(--space-md);
}

.contact-method {
    display: flex;
    align-items: center;
    gap: var(--space-md);
    margin-bottom: var(--space-md);
}

.contact-icon {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 50px;
    height: 50px;
    background-color: var(--bg-secondary);
    border-radius: var(--radius-full);
    color: var(--primary);
    font-size: 1.25rem;
}

.contact-details h4 {
    margin-bottom: 0;
}

.contact-details p {
    color: var(--text-secondary);
    margin-bottom: 0;
}

.social-links {
    display: flex;
    gap: var(--space-md);
    margin-top: var(--space-lg);
}

.social-link {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    background-color: var(--bg-secondary);
    border-radius: var(--radius-full);
    color: var(--primary);
    font-size: 1.25rem;
    transition: all var(--transition-normal);
}

.social-link:hover {
    background-color: var(--primary);
    color: var(--white);
    transform: translateY(-5px);
}

.contact-form {
    background-color: var(--card-bg);
    border-radius: var(--radius-md);
    box-shadow: var(--card-shadow);
    padding: var(--space-xl);
}

.form-group {
    margin-bottom: var(--space-lg);
}

.form-label {
    display: block;
    margin-bottom: var(--space-sm);
    font-weight: 500;
    color: var(--text-secondary);
}

.form-control {
    width: 100%;
    padding: var(--space-sm) var(--space-md);
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    color: var(--text-primary);
    font-family: var(--font-sans);
    transition: border-color var(--transition-fast);
}

.form-control:focus {
    outline: none;
    border-color: var(--primary);
}

textarea.form-control {
    min-height: 150px;
    resize: vertical;
}

/* Footer */
.footer {
    background-color: var(--bg-secondary);
    padding: var(--space-xl) 0;
    margin-top: auto;
}

.footer-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
}

.footer-logo {
    font-family: var(--font-display);
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: var(--space-md);
}

.footer-nav {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: var(--space-lg);
    margin-bottom: var(--space-lg);
}

.footer-nav-link {
    color: var(--text-secondary);
    font-weight: 500;
    transition: color var(--transition-fast);
}

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

.footer-social {
    display: flex;
    gap: var(--space-md);
    margin-bottom: var(--space-lg);
}

.copyright {
    color: var(--text-tertiary);
    font-size: 0.875rem;
}

/* Responsive Styles */
@media (min-width: 768px) {
    .nav-desktop {
        display: block;
    }
    
    .mobile-menu-toggle {
        display: none;
    }
    
    .hero .container {
        flex-direction: row;
        align-items: center;
    }
    
    .hero-content, .hero-image {
        flex: 1;
    }
    
    .hero-image {
        margin-top: 0;
    }
    
    .about-content, .skills-content, .contact-content {
        flex-direction: row;
    }
    
    .about-info, .about-visual {
        flex: 1;
    }
    
    .contact-info, .contact-form {
        flex: 1;
    }
    
    .blob-animation {
        width: 400px;
        height: 400px;
    }
}

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

.animate-fadeIn {
    animation: fadeIn 1s ease forwards;
}

/* Utility Classes */
.text-center {
    text-align: center;
}

.mb-1 {
    margin-bottom: var(--space-sm);
}

.mb-2 {
    margin-bottom: var(--space-md);
}

.mb-3 {
    margin-bottom: var(--space-lg);
}

.mb-4 {
    margin-bottom: var(--space-xl);
}

.mt-1 {
    margin-top: var(--space-sm);
}

.mt-2 {
    margin-top: var(--space-md);
}

.mt-3 {
    margin-top: var(--space-lg);
}

.mt-4 {
    margin-top: var(--space-xl);
}

.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border-width: 0;
}

/* Back to top button */
.back-to-top {
    position: fixed;
    bottom: var(--space-md);
    right: var(--space-md);
    width: 50px;
    height: 50px;
    border-radius: var(--radius-full);
    background-color: var(--primary);
    color: var(--white);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.25rem;
    box-shadow: var(--shadow-md);
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-normal);
    z-index: 90;
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
}

.back-to-top:hover {
    background-color: var(--primary-dark);
    transform: translateY(-5px);
}