/* ========================================
   CSS Variables & Theme System
   ======================================== */

:root {
    /* Light Theme Colors */
    --bg-primary: #ffffff;
    --bg-secondary: #f8fafc;
    --bg-tertiary: #f1f5f9;
    --bg-card: #ffffff;
    --bg-hover: #f1f5f9;
    
    --text-primary: #0f172a;
    --text-secondary: #475569;
    --text-tertiary: #94a3b8;
    --text-muted: #64748b;
    
    --accent-primary: #6366f1;
    --accent-secondary: #8b5cf6;
    --accent-gradient: linear-gradient(135deg, #6366f1 0%, #8b5cf6 100%);
    
    --border-color: #e2e8f0;
    --border-light: #f1f5f9;
    
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);
    --shadow-glow: 0 0 40px -10px var(--accent-primary);
    
    /* Typography */
    --font-primary: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-display: 'Playfair Display', Georgia, serif;
    
    --text-xs: 0.75rem;
    --text-sm: 0.875rem;
    --text-base: 1rem;
    --text-lg: 1.125rem;
    --text-xl: 1.25rem;
    --text-2xl: 1.5rem;
    --text-3xl: 1.875rem;
    --text-4xl: 2.25rem;
    --text-5xl: 3rem;
    --text-6xl: 3.75rem;
    
    /* Spacing */
    --space-1: 0.25rem;
    --space-2: 0.5rem;
    --space-3: 0.75rem;
    --space-4: 1rem;
    --space-5: 1.25rem;
    --space-6: 1.5rem;
    --space-8: 2rem;
    --space-10: 2.5rem;
    --space-12: 3rem;
    --space-16: 4rem;
    --space-20: 5rem;
    --space-24: 6rem;
    
    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-base: 250ms ease;
    --transition-slow: 350ms ease;
    --transition-slower: 500ms ease;
    
    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    --radius-2xl: 1.5rem;
    --radius-full: 9999px;
}

/* Dark Theme */
[data-theme="dark"] {
    --bg-primary: #0f172a;
    --bg-secondary: #1e293b;
    --bg-tertiary: #334155;
    --bg-card: #1e293b;
    --bg-hover: #334155;
    
    --text-primary: #f8fafc;
    --text-secondary: #cbd5e1;
    --text-tertiary: #64748b;
    --text-muted: #94a3b8;
    
    --accent-primary: #818cf8;
    --accent-secondary: #a78bfa;
    --accent-gradient: linear-gradient(135deg, #818cf8 0%, #a78bfa 100%);
    
    --border-color: #334155;
    --border-light: #1e293b;
    
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.3);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.4), 0 2px 4px -2px rgb(0 0 0 / 0.4);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.4), 0 4px 6px -4px rgb(0 0 0 / 0.4);
    --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.5), 0 8px 10px -6px rgb(0 0 0 / 0.5);
    --shadow-glow: 0 0 40px -10px var(--accent-primary);
}

/* ========================================
   Base Styles & Reset
   ======================================== */

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

html {
    scroll-behavior: smooth;
    font-size: 16px;
    touch-action: pan-x pan-y;
    -webkit-text-size-adjust: 100%;
    -moz-text-size-adjust: 100%;
    -ms-text-size-adjust: 100%;
    text-size-adjust: 100%;
}

body {
    font-family: var(--font-primary);
    font-size: var(--text-base);
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--bg-primary);
    transition: background-color var(--transition-slow), color var(--transition-slow);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    touch-action: manipulation;
    -webkit-user-select: none;
    -moz-user-select: none;
    -ms-user-select: none;
    user-select: none;
}

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

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

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

ul, ol {
    list-style: none;
}

/* ========================================
   Utility Classes
   ======================================== */

.container {
    width: 100%;
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 var(--space-6);
}

@media (min-width: 640px) {
    .container {
        padding: 0 var(--space-8);
    }
}

@media (min-width: 1024px) {
    .container {
        padding: 0 var(--space-12);
    }
}

/* ========================================
   Navigation
   ======================================== */

.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(var(--bg-primary), 0.8);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid transparent;
    transition: all var(--transition-base);
}

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

.nav-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 72px;
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 var(--space-6);
}

@media (min-width: 640px) {
    .nav-container {
        padding: 0 var(--space-8);
    }
}

@media (min-width: 1024px) {
    .nav-container {
        padding: 0 var(--space-12);
    }
}

/* Logo */
.nav-logo {
    display: flex;
    align-items: center;
    gap: var(--space-1);
    font-weight: 700;
    font-size: var(--text-xl);
}

.logo-text {
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.logo-dot {
    width: 6px;
    height: 6px;
    background: var(--accent-primary);
    border-radius: var(--radius-full);
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0%, 100% { opacity: 1; transform: scale(1); }
    50% { opacity: 0.7; transform: scale(1.2); }
}

/* Navigation Menu */
.nav-menu {
    display: none;
    align-items: center;
    gap: var(--space-8);
}

@media (min-width: 768px) {
    .nav-menu {
        display: flex;
    }
}

.nav-link {
    position: relative;
    font-size: var(--text-sm);
    font-weight: 500;
    color: var(--text-secondary);
    padding: var(--space-2) 0;
    transition: color var(--transition-fast);
}

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

.nav-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--accent-gradient);
    transition: width var(--transition-base);
}

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

/* Navigation Actions */
.nav-actions {
    display: flex;
    align-items: center;
    gap: var(--space-4);
}

/* Theme Toggle */
.theme-toggle {
    width: 44px;
    height: 44px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: var(--radius-lg);
    color: var(--text-secondary);
    background: var(--bg-secondary);
    transition: all var(--transition-fast);
}

.theme-toggle:hover {
    color: var(--text-primary);
    background: var(--bg-tertiary);
}

.theme-toggle svg {
    width: 20px;
    height: 20px;
    position: absolute;
    transition: all var(--transition-slow);
}

.sun-icon {
    opacity: 1;
    transform: rotate(0deg) scale(1);
}

.moon-icon {
    opacity: 0;
    transform: rotate(90deg) scale(0);
}

[data-theme="dark"] .sun-icon {
    opacity: 0;
    transform: rotate(-90deg) scale(0);
}

[data-theme="dark"] .moon-icon {
    opacity: 1;
    transform: rotate(0deg) scale(1);
}

/* Mobile Toggle */
.mobile-toggle {
    display: flex;
    flex-direction: column;
    justify-content: center;
    gap: 5px;
    width: 44px;
    height: 44px;
    padding: var(--space-3);
    border-radius: var(--radius-lg);
    background: var(--bg-secondary);
}

@media (min-width: 768px) {
    .mobile-toggle {
        display: none;
    }
}

.hamburger-line {
    display: block;
    width: 100%;
    height: 2px;
    background: var(--text-primary);
    border-radius: var(--radius-full);
    transition: all var(--transition-base);
    transform-origin: center;
}

.mobile-toggle.active .hamburger-line:nth-child(1) {
    transform: translateY(7px) rotate(45deg);
}

.mobile-toggle.active .hamburger-line:nth-child(2) {
    opacity: 0;
    transform: scaleX(0);
}

.mobile-toggle.active .hamburger-line:nth-child(3) {
    transform: translateY(-7px) rotate(-45deg);
}

/* Mobile Menu */
.nav-menu.mobile-open {
    display: flex;
    flex-direction: column;
    position: fixed;
    top: 72px;
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--bg-primary);
    padding: var(--space-8);
    gap: var(--space-6);
    z-index: 999;
}

.nav-menu.mobile-open .nav-link {
    font-size: var(--text-xl);
    padding: var(--space-4) 0;
}

/* ========================================
   Buttons
   ======================================== */

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-2);
    padding: var(--space-3) var(--space-6);
    font-size: var(--text-sm);
    font-weight: 500;
    border-radius: var(--radius-lg);
    transition: all var(--transition-fast);
}

.btn svg {
    width: 16px;
    height: 16px;
    transition: transform var(--transition-fast);
}

.btn-primary {
    background: var(--accent-gradient);
    color: white;
    box-shadow: var(--shadow-md);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg), var(--shadow-glow);
}

.btn-primary:hover svg {
    transform: translateX(4px);
}

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

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

.btn-full {
    width: 100%;
}

/* ========================================
   Hero Section
   ======================================== */

.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: calc(72px + var(--space-12)) var(--space-6) var(--space-12);
    overflow: hidden;
}

.hero-background {
    position: absolute;
    inset: 0;
    z-index: 0;
    overflow: hidden;
}

.gradient-orb {
    position: absolute;
    border-radius: 50%;
    filter: blur(80px);
    opacity: 0.5;
    animation: float 20s ease-in-out infinite;
}

.orb-1 {
    width: 600px;
    height: 600px;
    background: var(--accent-primary);
    top: -200px;
    right: -200px;
    animation-delay: 0s;
}

.orb-2 {
    width: 400px;
    height: 400px;
    background: var(--accent-secondary);
    bottom: -100px;
    left: -100px;
    animation-delay: -7s;
}

.orb-3 {
    width: 300px;
    height: 300px;
    background: linear-gradient(135deg, #ec4899 0%, #f43f5e 100%);
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    animation-delay: -14s;
    opacity: 0.3;
}

@keyframes float {
    0%, 100% {
        transform: translate(0, 0) scale(1);
    }
    25% {
        transform: translate(30px, -30px) scale(1.05);
    }
    50% {
        transform: translate(-20px, 20px) scale(0.95);
    }
    75% {
        transform: translate(-30px, -20px) scale(1.02);
    }
}

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

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: var(--space-2);
    padding: var(--space-2) var(--space-4);
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-full);
    margin-bottom: var(--space-6);
}

.badge-dot {
    width: 8px;
    height: 8px;
    background: #22c55e;
    border-radius: var(--radius-full);
    animation: pulse 2s infinite;
}

.badge-text {
    font-size: var(--text-sm);
    font-weight: 500;
    color: var(--text-secondary);
}

.hero-title {
    font-family: var(--font-display);
    font-size: var(--text-4xl);
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: var(--space-6);
}

@media (min-width: 640px) {
    .hero-title {
        font-size: var(--text-5xl);
    }
}

@media (min-width: 1024px) {
    .hero-title {
        font-size: var(--text-6xl);
    }
}

.title-line {
    display: block;
}

.title-line.highlight {
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-description {
    font-size: var(--text-lg);
    color: var(--text-secondary);
    margin-bottom: var(--space-8);
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.hero-actions {
    display: flex;
    flex-direction: column;
    gap: var(--space-4);
    justify-content: center;
    align-items: center;
}

@media (min-width: 480px) {
    .hero-actions {
        flex-direction: row;
    }
}

.hero-scroll {
    position: absolute;
    bottom: var(--space-8);
    left: 50%;
    transform: translateX(-50%);
    z-index: 1;
}

.scroll-indicator {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--space-2);
}

.scroll-text {
    font-size: var(--text-xs);
    color: var(--text-tertiary);
    text-transform: uppercase;
    letter-spacing: 0.1em;
}

.scroll-line {
    width: 1px;
    height: 60px;
    background: linear-gradient(to bottom, var(--accent-primary), transparent);
    animation: scrollLine 2s ease-in-out infinite;
}

@keyframes scrollLine {
    0%, 100% {
        transform: scaleY(0);
        transform-origin: top;
    }
    50% {
        transform: scaleY(1);
        transform-origin: top;
    }
    51% {
        transform-origin: bottom;
    }
}

/* ========================================
   Section Styles
   ======================================== */

.section-header {
    text-align: center;
    margin-bottom: var(--space-16);
}

.section-tag {
    display: inline-block;
    font-size: var(--text-sm);
    font-weight: 600;
    color: var(--accent-primary);
    text-transform: uppercase;
    letter-spacing: 0.1em;
    margin-bottom: var(--space-4);
}

.section-title {
    font-family: var(--font-display);
    font-size: var(--text-3xl);
    font-weight: 700;
    color: var(--text-primary);
    line-height: 1.3;
}

@media (min-width: 640px) {
    .section-title {
        font-size: var(--text-4xl);
    }
}

.section-description {
    font-size: var(--text-lg);
    color: var(--text-secondary);
    max-width: 600px;
    margin: var(--space-4) auto 0;
}

/* ========================================
   About Section
   ======================================== */

.about {
    padding: var(--space-24) 0;
    background: var(--bg-secondary);
}

.about-grid {
    display: grid;
    gap: var(--space-12);
    align-items: center;
}

@media (min-width: 1024px) {
    .about-grid {
        grid-template-columns: 1fr 1.5fr;
        gap: var(--space-16);
    }
}

.about-image {
    position: relative;
}

.image-wrapper {
    position: relative;
}

.image-placeholder {
    aspect-ratio: 1;
    background: var(--bg-tertiary);
    border-radius: var(--radius-2xl);
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    z-index: 1;
}

.image-placeholder svg {
    width: 120px;
    height: 120px;
    color: var(--text-tertiary);
}

.image-decoration {
    position: absolute;
    inset: -20px;
    background: var(--accent-gradient);
    border-radius: var(--radius-2xl);
    opacity: 0.1;
    z-index: 0;
}

.about-content {
    display: flex;
    flex-direction: column;
    gap: var(--space-8);
}

.about-text {
    display: flex;
    flex-direction: column;
    gap: var(--space-4);
}

.about-text p {
    font-size: var(--text-lg);
    color: var(--text-secondary);
    line-height: 1.8;
}

.skills-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-6);
}

@media (min-width: 640px) {
    .skills-grid {
        grid-template-columns: repeat(4, 1fr);
    }
}

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

.skill-icon {
    width: 56px;
    height: 56px;
    margin: 0 auto var(--space-4);
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-xl);
    color: var(--accent-primary);
    transition: all var(--transition-fast);
}

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

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

.skill-item h4 {
    font-size: var(--text-base);
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: var(--space-1);
}

.skill-item p {
    font-size: var(--text-sm);
    color: var(--text-muted);
}

/* ========================================
   Projects Section
   ======================================== */

.projects {
    padding: var(--space-24) 0;
    background: var(--bg-primary);
}

.projects-filter {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: var(--space-3);
    margin-bottom: var(--space-12);
}

.filter-btn {
    padding: var(--space-2) var(--space-5);
    font-size: var(--text-sm);
    font-weight: 500;
    color: var(--text-secondary);
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-full);
    transition: all var(--transition-fast);
    cursor: pointer;
}

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

@media (max-width: 640px) {
    .projects-filter {
        gap: var(--space-2);
        margin-bottom: var(--space-8);
    }
    
    .filter-btn {
        padding: var(--space-2) var(--space-4);
        font-size: var(--text-xs);
    }
}

.projects-grid {
    display: grid;
    gap: var(--space-6);
    grid-template-columns: 1fr;
}

@media (min-width: 480px) {
    .projects-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: var(--space-6);
    }
}

@media (min-width: 768px) {
    .projects-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: var(--space-8);
    }
}

@media (min-width: 1024px) {
    .projects-grid {
        grid-template-columns: repeat(3, 1fr);
        gap: var(--space-8);
    }
}

.project-card {
    background: var(--bg-card);
    border: 2px solid var(--border-color);
    border-radius: var(--radius-xl);
    overflow: hidden;
    transition: all var(--transition-base);
    cursor: pointer;
    position: relative;
}

.project-card::before {
    content: '';
    position: absolute;
    inset: 0;
    border-radius: var(--radius-xl);
    border: 3px solid transparent;
    transition: all var(--transition-base);
    pointer-events: none;
    z-index: 10;
}

.project-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-xl), 0 0 0 1px var(--accent-primary);
    border-color: var(--accent-primary);
}

.project-card:focus {
    outline: none;
}

.project-card:focus::before,
.project-card.active::before {
    border-color: var(--accent-primary);
    box-shadow: 0 0 0 4px rgba(99, 102, 241, 0.15), 0 0 20px rgba(99, 102, 241, 0.3);
}

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

.project-card-content {
    display: block;
    width: 100%;
    height: 100%;
}

.project-image {
    position: relative;
    aspect-ratio: 16 / 9;
    overflow: hidden;
    background: var(--bg-secondary);
}

.project-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform var(--transition-slow), opacity var(--transition-base);
    opacity: 0;
}

.project-image img.loaded {
    opacity: 1;
}

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

.project-card.hidden {
    display: none;
}

.project-info {
    padding: var(--space-6);
    display: flex;
    flex-direction: column;
    gap: var(--space-4);
    min-height: 280px;
}

.project-tags {
    display: flex;
    gap: var(--space-2);
    flex-wrap: wrap;
}

.tag {
    padding: var(--space-1) var(--space-3);
    background: var(--bg-secondary);
    border-radius: var(--radius-full);
    font-size: var(--text-xs);
    font-weight: 500;
    color: var(--accent-primary);
    transition: all var(--transition-base);
}

.project-card:hover .tag,
.project-card.active .tag {
    background: var(--accent-primary);
    color: white;
}

.project-title {
    font-size: var(--text-xl);
    font-weight: 600;
    color: var(--text-primary);
    margin: 0;
    transition: color var(--transition-base);
}

.project-card:hover .project-title,
.project-card.active .project-title {
    color: var(--accent-primary);
}

.project-description {
    font-size: var(--text-sm);
    color: var(--text-secondary);
    line-height: 1.6;
    margin: 0;
    flex-grow: 1;
}

.project-actions {
    display: flex;
    justify-content: center;
    margin-top: auto;
    padding-top: var(--space-2);
}

.project-action-btn {
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--bg-secondary);
    border-radius: var(--radius-lg);
    color: var(--text-secondary);
    transition: all var(--transition-base);
    cursor: pointer;
    text-decoration: none;
    border: none;
}

.project-action-btn:hover {
    background: var(--accent-primary);
    color: white;
    transform: scale(1.1);
}

.project-card.active .project-action-btn {
    background: var(--accent-primary);
    color: white;
}

.project-action-btn svg {
    width: 18px;
    height: 18px;
}

.project-action-btn svg {
    width: 20px;
    height: 20px;
}

.project-info {
    padding: var(--space-6);
}

.project-tags {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-2);
    margin-bottom: var(--space-3);
}

.tag {
    font-size: var(--text-xs);
    font-weight: 500;
    color: var(--accent-primary);
    background: rgba(99, 102, 241, 0.1);
    padding: var(--space-1) var(--space-3);
    border-radius: var(--radius-full);
}

[data-theme="dark"] .tag {
    background: rgba(129, 140, 248, 0.15);
}

.project-title {
    font-size: var(--text-xl);
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: var(--space-2);
}

.project-description {
    font-size: var(--text-sm);
    color: var(--text-muted);
    line-height: 1.6;
}

/* ========================================
   Stats Section
   ======================================== */

.stats {
    padding: var(--space-16) 0;
    background: var(--accent-gradient);
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-8);
    text-align: center;
}

@media (min-width: 640px) {
    .stats-grid {
        grid-template-columns: repeat(4, 1fr);
    }
}

.stat-item {
    color: white;
}

.stat-number,
.stat-suffix {
    font-family: var(--font-display);
    font-size: var(--text-4xl);
    font-weight: 700;
}

@media (min-width: 640px) {
    .stat-number,
    .stat-suffix {
        font-size: var(--text-5xl);
    }
}

.stat-label {
    display: block;
    font-size: var(--text-sm);
    opacity: 0.9;
    margin-top: var(--space-2);
}

/* ========================================
   Contact Section
   ======================================== */

.contact {
    padding: var(--space-24) 0;
    background: var(--bg-secondary);
}

.contact-wrapper {
    display: grid;
    gap: var(--space-12);
}

@media (min-width: 1024px) {
    .contact-wrapper {
        grid-template-columns: 1fr 1.2fr;
        gap: var(--space-16);
    }
}

.contact-info .section-header {
    text-align: left;
    margin-bottom: var(--space-6);
}

.contact-description {
    font-size: var(--text-lg);
    color: var(--text-secondary);
    margin-bottom: var(--space-8);
}

.contact-details {
    display: flex;
    flex-direction: column;
    gap: var(--space-4);
    margin-bottom: var(--space-8);
}

.contact-item {
    display: flex;
    align-items: center;
    gap: var(--space-4);
}

.contact-icon {
    width: 48px;
    height: 48px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    color: var(--accent-primary);
}

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

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

.contact-label {
    font-size: var(--text-sm);
    color: var(--text-muted);
}

.contact-text a,
.contact-text span:last-child {
    font-weight: 500;
    color: var(--text-primary);
}

.contact-text a:hover {
    color: var(--accent-primary);
}

.social-links {
    display: flex;
    gap: var(--space-3);
}

.social-link {
    width: 44px;
    height: 44px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    color: var(--text-secondary);
    transition: all var(--transition-fast);
}

.social-link:hover {
    background: var(--accent-primary);
    border-color: var(--accent-primary);
    color: white;
    transform: translateY(-2px);
}

.social-link svg {
    width: 20px;
    height: 20px;
}

/* Contact Form */
.contact-form-wrapper {
    background: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-xl);
    padding: var(--space-8);
}

.contact-form {
    display: flex;
    flex-direction: column;
    gap: var(--space-6);
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: var(--space-2);
}

.form-group label {
    font-size: var(--text-sm);
    font-weight: 500;
    color: var(--text-primary);
}

.form-group input,
.form-group textarea {
    padding: var(--space-3) var(--space-4);
    font-size: var(--text-base);
    color: var(--text-primary);
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    transition: all var(--transition-fast);
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--accent-primary);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
}

.form-group input::placeholder,
.form-group textarea::placeholder {
    color: var(--text-tertiary);
}

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

/* Collaboration Image */
.collaboration-image {
    position: relative;
    width: 100%;
    height: 300px;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
    border-radius: var(--radius-xl);
    background: var(--bg-secondary);
}

.collaboration-image img {
    max-width: 80%;
    max-height: 80%;
    object-fit: scale-down;
    transition: transform var(--transition-slow);
}

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

.image-overlay {
    position: absolute;
    inset: 0;
    background: linear-gradient(to top, rgba(0, 0, 0, 0.8) 0%, rgba(0, 0, 0, 0.4) 50%, transparent 100%);
    display: flex;
    align-items: flex-end;
    padding: var(--space-8);
}

.overlay-content {
    color: white;
    animation: fadeInUp var(--transition-slow) ease;
}

.overlay-content h3 {
    font-size: var(--text-2xl);
    font-weight: 700;
    margin-bottom: var(--space-3);
}

.overlay-content p {
    font-size: var(--text-base);
    opacity: 0.9;
    line-height: 1.6;
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* ========================================
   Footer
   ======================================== */

.footer {
    padding: var(--space-16) 0 var(--space-8);
    background: var(--bg-primary);
    border-top: 1px solid var(--border-color);
}

.footer-content {
    display: grid;
    gap: var(--space-8);
    margin-bottom: var(--space-12);
}

@media (min-width: 640px) {
    .footer-content {
        grid-template-columns: 1fr auto;
        align-items: start;
    }
}

@media (max-width: 639px) {
    .footer-content {
        grid-template-columns: 1fr;
        gap: var(--space-6);
    }
}

.footer-logo {
    display: inline-flex;
    align-items: center;
    gap: var(--space-1);
    font-size: var(--text-xl);
    font-weight: 700;
    margin-bottom: var(--space-3);
}

.footer-tagline {
    font-size: var(--text-base);
    color: var(--text-muted);
}

/* 友情链接样式 */
.footer-friendlinks {
    margin-top: var(--space-8);
}

.friendlinks-title {
    font-size: var(--text-sm);
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: var(--space-4);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.friendlinks-list {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-4);
    align-items: center;
}

.friendlinks-list a {
    font-size: var(--text-sm);
    color: var(--text-muted);
    transition: color var(--transition-fast);
    text-decoration: none;
}

.friendlinks-list a:hover {
    color: var(--accent-primary);
}

@media (max-width: 640px) {
    .footer-friendlinks {
        margin-top: var(--space-6);
    }
    
    .friendlinks-title {
        margin-bottom: var(--space-3);
    }
    
    .friendlinks-list {
        gap: var(--space-3);
    }
}

.footer-links {
    display: flex;
    gap: var(--space-12);
}

@media (max-width: 639px) {
    .footer-links {
        flex-direction: column;
        gap: var(--space-6);
    }
}

.footer-column h4 {
    font-size: var(--text-sm);
    font-weight: 600;
    color: var(--text-primary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: var(--space-4);
}

.footer-column ul {
    display: flex;
    flex-direction: column;
    gap: var(--space-3);
}

.footer-column a {
    font-size: var(--text-sm);
    color: var(--text-muted);
    transition: color var(--transition-fast);
}

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

.footer-bottom {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding-top: var(--space-8);
    border-top: 1px solid var(--border-color);
}

.footer-bottom p {
    font-size: var(--text-sm);
    color: var(--text-tertiary);
}

.back-to-top {
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    color: var(--text-secondary);
    transition: all var(--transition-fast);
}

.back-to-top:hover {
    background: var(--accent-primary);
    border-color: var(--accent-primary);
    color: white;
    transform: translateY(-2px);
}

.back-to-top svg {
    width: 18px;
    height: 18px;
}

/* ========================================
   Animations & Effects
   ======================================== */

/* Fade In Up Animation */
.fade-in-up {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity var(--transition-slower), transform var(--transition-slower);
}

.fade-in-up.visible {
    opacity: 1;
    transform: translateY(0);
}

/* Stagger Animation Delays */
.stagger-1 { transition-delay: 0.1s; }
.stagger-2 { transition-delay: 0.2s; }
.stagger-3 { transition-delay: 0.3s; }
.stagger-4 { transition-delay: 0.4s; }
.stagger-5 { transition-delay: 0.5s; }
.stagger-6 { transition-delay: 0.6s; }

/* ========================================
   Responsive Design
   ======================================== */

@media (max-width: 767px) {
    .nav-menu {
        position: fixed;
        top: 72px;
        left: 0;
        right: 0;
        bottom: 0;
        background: var(--bg-primary);
        flex-direction: column;
        padding: var(--space-8);
        gap: var(--space-4);
        transform: translateX(100%);
        transition: transform var(--transition-base);
    }
    
    .nav-menu.mobile-open {
        transform: translateX(0);
    }
    
    .nav-link {
        font-size: var(--text-xl);
        padding: var(--space-3) 0;
    }
    
    .collaboration-image {
        height: 250px;
    }
    
    .image-overlay {
        padding: var(--space-6);
    }
    
    .overlay-content h3 {
        font-size: var(--text-xl);
    }
    
    .overlay-content p {
        font-size: var(--text-sm);
    }
    
    .project-info {
        min-height: 240px;
    }
}

/* Reduced Motion */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
    
    html {
        scroll-behavior: auto;
    }
}

/* Print Styles */
@media print {
    .navbar,
    .hero-background,
    .theme-toggle,
    .mobile-toggle,
    .hero-scroll,
    .back-to-top {
        display: none !important;
    }
    
    .hero {
        min-height: auto;
        padding: var(--space-8) 0;
    }
    
    body {
        background: white !important;
        color: black !important;
    }
}