:root {
    /* Colors */
    --bg: #ffffff;
    --text: #171717;
    --text-muted: #737373;
    --text-accent: #0969da;
    --border: #e5e5e5;

    /* Typography */
    --font-sans: 'Inter var', 'Inter', system-ui, sans-serif;

    /* Spacing */
    --space-1: 0.25rem;
    --space-2: 0.5rem;
    --space-3: 0.75rem;
    --space-4: 1rem;
    --space-6: 1.5rem;
    --space-8: 2rem;
    --space-12: 3rem;
    --space-16: 4rem;

    /* Layout */
    --container-width: 600px;
    --nav-height: 60px;
}

[data-theme="dark"] {
    --bg: #0a0a0a;
    --text: #f5f5f5;
    --text-muted: #737373;
    --text-accent: #58a6ff;
    --border: #262626;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-sans);
    font-size: 1rem;
    line-height: 1.6;
    color: var(--text);
    background: var(--bg);
    transition: background 0.2s, color 0.2s;
    font-feature-settings: 'cv02', 'cv03', 'cv04', 'cv11';
}

/* Navigation */
.nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: var(--nav-height);
    background: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border);
    z-index: 100;
    transition: background 0.2s;
}

[data-theme="dark"] .nav {
    background: rgba(10, 10, 10, 0.8);
}

.nav-container {
    max-width: var(--container-width);
    margin: 0 auto;
    padding: 0 var(--space-6);
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
}

.nav-links {
    display: flex;
    gap: var(--space-8);
    list-style: none;
}

.nav-controls {
    position: absolute;
    right: 0;
    display: flex;
    align-items: center;
    gap: var(--space-4);
}

.nav-link {
    color: var(--text-muted);
    text-decoration: none;
    font-size: 0.875rem;
    font-weight: 500;
    padding: var(--space-2) var(--space-3);
    border-radius: 0.375rem;
    transition: all 0.2s;
    position: relative;
}

.nav-link:hover {
    color: var(--text);
    background: rgba(0, 0, 0, 0.05);
}

[data-theme="dark"] .nav-link:hover {
    background: rgba(255, 255, 255, 0.05);
}

.nav-link.active {
    color: var(--text);
    background: rgba(0, 0, 0, 0.1);
}

[data-theme="dark"] .nav-link.active {
    background: rgba(255, 255, 255, 0.1);
}

.mobile-menu-toggle {
    display: none;
    background: none;
    border: none;
    color: var(--text-muted);
    cursor: pointer;
    padding: var(--space-2);
    border-radius: 0.375rem;
    transition: color 0.2s;
}

.mobile-menu-toggle:hover {
    color: var(--text);
}

.nav-mobile-spacer {
    display: none;
}

/* Mobile Navigation Styles */
@media (max-width: 768px) {
    .mobile-menu-toggle {
        display: block !important;
    }

    .nav-container {
        justify-content: flex-end;
    }

    .nav-mobile-spacer {
        display: block;
        flex: 1;
    }

    .nav-links {
        position: fixed;
        top: var(--nav-height);
        left: 0;
        right: 0;
        background: var(--bg);
        flex-direction: column;
        gap: 0;
        padding: var(--space-4);
        border-bottom: 1px solid var(--border);
        transform: translateY(-100%);
        opacity: 0;
        visibility: hidden;
        transition: transform 0.3s ease, opacity 0.3s ease, visibility 0.3s;
    }

    .nav-links.mobile-open {
        transform: translateY(0);
        opacity: 1;
        visibility: visible;
    }

    .nav-link {
        display: block;
        padding: var(--space-3) var(--space-4);
        border-radius: 0.375rem;
    }
}

.theme-toggle {
    background: none;
    border: none;
    color: var(--text-muted);
    cursor: pointer;
    padding: var(--space-2);
    border-radius: 0.375rem;
    transition: color 0.2s;
}

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

/* Main Content */
.main {
    margin-top: var(--nav-height);
    max-width: var(--container-width);
    margin-left: auto;
    margin-right: auto;
    padding: 0 var(--space-6);
    min-height: calc(100vh - var(--nav-height) - 200px);
}

.page-header {
    padding: var(--space-12) 0 var(--space-8) 0;
    text-align: center;
}

.page-title {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: var(--space-4);
    letter-spacing: -0.02em;
}

.page-subtitle {
    font-size: 1.125rem;
    color: var(--text-muted);
    line-height: 1.7;
}

.content {
    padding-bottom: var(--space-12);
}

.content h1,
.content h2,
.content h3 {
    margin: var(--space-6) 0 var(--space-4) 0;
    font-weight: 600;
    letter-spacing: -0.01em;
}

.content h1:first-child,
.content h2:first-child,
.content h3:first-child {
    margin-top: 0;
}

.content p {
    margin-bottom: var(--space-4);
    color: var(--text-muted);
    line-height: 1.7;
}

.content ul,
.content ol {
    margin-bottom: var(--space-4);
    padding-left: var(--space-6);
}

.content li {
    margin-bottom: var(--space-2);
    color: var(--text-muted);
}

.content a {
    color: var(--text-accent);
    text-decoration: underline;
    text-underline-offset: 2px;
}

.content blockquote {
    border-left: 3px solid var(--text-accent);
    padding-left: var(--space-4);
    margin: var(--space-6) 0;
    font-style: italic;
    color: var(--text-muted);
}

.content code {
    background: var(--border);
    padding: var(--space-1) var(--space-2);
    border-radius: 0.25rem;
    font-size: 0.875rem;
    font-family: 'SF Mono', Consolas, monospace;
}

.content pre {
    background: var(--border);
    padding: var(--space-4);
    border-radius: 0.375rem;
    overflow-x: auto;
    margin: var(--space-6) 0;
}

.content pre code {
    background: none;
    padding: 0;
}

/* Projects Content Styling */
.projects-content {
    animation: fadeIn 0.6s ease-out;
}

.intro {
    font-size: 1.125rem;
    line-height: 1.7;
    color: var(--text-muted);
    margin-bottom: var(--space-8);
    text-align: center;
}

.project-card {
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: var(--space-6);
    margin-bottom: var(--space-6);
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

.project-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: linear-gradient(90deg, var(--text-accent), #8b5cf6);
    opacity: 0;
    transition: opacity 0.3s ease;
}

.project-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.1);
    border-color: var(--text-accent);
}

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

[data-theme="dark"] .project-card:hover {
    box-shadow: 0 8px 25px rgba(255, 255, 255, 0.05);
}

.project-card h3 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: var(--space-2);
    color: var(--text);
    display: flex;
    align-items: center;
    gap: var(--space-2);
}

.tech-stack {
    color: var(--text-accent);
    font-weight: 500;
    margin-bottom: var(--space-3);
    font-size: 0.9rem;
}

.project-card p {
    color: var(--text-muted);
    line-height: 1.6;
    margin-bottom: var(--space-4);
}

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

.features strong {
    color: var(--text);
    font-weight: 600;
}

.features ul {
    margin-top: var(--space-2);
    margin-left: var(--space-4);
}

.features li {
    color: var(--text-muted);
    margin-bottom: var(--space-1);
    position: relative;
}

.features li::before {
    content: '→';
    color: var(--text-accent);
    font-weight: bold;
    position: absolute;
    left: -1.2rem;
}

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

.project-links a {
    color: var(--text-accent);
    text-decoration: none;
    font-weight: 500;
    padding: var(--space-2) var(--space-3);
    border: 1px solid var(--text-accent);
    border-radius: 6px;
    font-size: 0.875rem;
    transition: all 0.2s ease;
    display: inline-flex;
    align-items: center;
    gap: var(--space-1);
}

.project-links a:hover {
    background: var(--text-accent);
    color: white;
    transform: translateY(-1px);
}

/* Side Projects */
.side-projects {
    display: grid;
    gap: var(--space-4);
    margin-top: var(--space-4);
}

.side-project {
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: var(--space-4);
    transition: all 0.2s ease;
}

.side-project:hover {
    border-color: var(--text-accent);
    transform: translateY(-1px);
}

.side-project h3 {
    font-size: 1.125rem;
    font-weight: 600;
    margin-bottom: var(--space-2);
    color: var(--text);
}

.side-project p {
    color: var(--text-muted);
    line-height: 1.5;
    margin: 0;
}

/* Call to Action */
.cta {
    text-align: center;
    margin-top: var(--space-8);
    padding: var(--space-6);
    background: linear-gradient(135deg, rgba(9, 105, 218, 0.05), rgba(139, 92, 246, 0.05));
    border-radius: 12px;
    border: 1px solid var(--border);
}

.cta p {
    margin: 0;
    font-size: 1.125rem;
}

.cta a {
    color: var(--text-accent);
    text-decoration: none;
    font-weight: 600;
    border-bottom: 2px solid transparent;
    transition: border-color 0.2s ease;
}

.cta a:hover {
    border-bottom-color: var(--text-accent);
}

/* Project Stats */
.project-stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--space-4);
    margin: var(--space-8) 0;
}

.stat-card {
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: var(--space-4);
    text-align: center;
    transition: all 0.2s ease;
}

.stat-card:hover {
    border-color: var(--text-accent);
    transform: translateY(-1px);
}

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

.stat-label {
    color: var(--text-muted);
    font-size: 0.875rem;
    margin-top: var(--space-1);
}

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

.fade-in {
    animation: fadeIn 0.6s ease-out;
}

/* Loading */
.loading {
    display: flex;
    justify-content: center;
    padding: var(--space-8);
    color: var(--text-muted);
}

/* Footer */
.footer {
    text-align: center;
    padding: var(--space-12) 0;
    border-top: 1px solid var(--border);
    color: var(--text-muted);
    font-size: 0.875rem;
}

.footer a {
    color: var(--text-accent);
    text-decoration: none;
}

/* Mobile */
@media (max-width: 768px) {
    .nav-container {
        justify-content: space-between;
    }

    .nav-links {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: rgba(255, 255, 255, 0.95);
        backdrop-filter: blur(12px);
        border-bottom: 1px solid var(--border);
        padding: var(--space-6) 0;
        flex-direction: column;
        gap: var(--space-2);
        box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
        z-index: 1000;
    }

    [data-theme="dark"] .nav-links {
        background: rgba(10, 10, 10, 0.95);
    }

    .nav-links.mobile-open {
        display: flex;
    }

    .nav-mobile-spacer {
        display: block;
        width: 24px;
    }

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

    .page-subtitle {
        font-size: 1rem;
    }

    /* Project Cards Mobile Optimization */
    .project-card {
        padding: var(--space-4);
        margin-bottom: var(--space-4);
    }

    .project-card h3 {
        font-size: 1.25rem;
    }

    .project-links {
        flex-direction: column;
        gap: var(--space-2);
    }

    .project-links a {
        text-align: center;
        justify-content: center;
    }

    /* Stats Grid Mobile */
    .project-stats {
        grid-template-columns: repeat(2, 1fr);
        gap: var(--space-3);
    }

    .stat-card {
        padding: var(--space-3);
    }

    .stat-number {
        font-size: 1.5rem;
    }

    /* Side Projects Mobile */
    .side-projects {
        gap: var(--space-3);
    }

    .side-project {
        padding: var(--space-3);
    }

    /* Analytics Section Mobile */
    .analytics-grid {
        grid-template-columns: 1fr;
        gap: var(--space-4);
    }

    .chart-container {
        height: 250px;
    }
}

/* Project Analytics */
.analytics-section {
    margin: var(--space-12) 0;
    padding: var(--space-8) 0;
    border-top: 1px solid var(--border);
}

.analytics-title {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: var(--space-8);
    text-align: center;
    letter-spacing: -0.01em;
}

.analytics-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--space-6);
    margin-bottom: var(--space-8);
}

.analytics-card {
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: 0.75rem;
    padding: var(--space-6);
    transition: all 0.2s ease;
}

.analytics-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.1);
    border-color: var(--text-accent);
}

[data-theme="dark"] .analytics-card:hover {
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.3);
}

.card-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: var(--space-4);
}

.card-title {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text);
}

.card-description {
    font-size: 0.875rem;
    color: var(--text-muted);
    margin-bottom: var(--space-4);
}

.card-icon {
    width: 20px;
    height: 20px;
    color: var(--text-accent);
}

.chart-container {
    position: relative;
    height: 250px;
    margin-top: var(--space-4);
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--space-4);
    margin-top: var(--space-8);
}

.stat-item {
    text-align: center;
    padding: var(--space-4);
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: 0.5rem;
    transition: all 0.2s ease;
}

.stat-item:hover {
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

.stat-number {
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--text-accent);
    display: block;
}

.stat-label {
    font-size: 0.875rem;
    color: var(--text-muted);
    margin-top: var(--space-1);
}

.timeline {
    margin-top: var(--space-8);
}

.timeline-list {
    list-style: none;
    padding: 0;
    position: relative;
    padding-left: var(--space-6);
}

.timeline-list::before {
    content: '';
    position: absolute;
    left: var(--space-2);
    top: 0;
    bottom: 0;
    width: 2px;
    background: var(--border);
}

.timeline-item {
    position: relative;
    padding-bottom: var(--space-6);
    margin-left: var(--space-4);
}

.timeline-item::before {
    content: '';
    position: absolute;
    left: calc(-1 * var(--space-6) - var(--space-2));
    top: var(--space-1);
    width: 10px;
    height: 10px;
    background: var(--text-accent);
    border-radius: 50%;
    border: 2px solid var(--bg);
}

.timeline-date {
    font-size: 0.75rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: var(--space-1);
}

.timeline-title {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text);
    margin-bottom: var(--space-1);
}

.timeline-description {
    font-size: 0.875rem;
    color: var(--text-muted);
    line-height: 1.5;
}

/* Animations */
.fade-in {
    animation: fadeIn 0.6s ease-out;
}

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