/* Reset and base styles */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

:root {
    --color-bg: #0f0f0f;
    --color-bg-secondary: #1a1a1a;
    --color-text: #e0e0e0;
    --color-text-muted: #888;
    --color-accent: #6366f1;
    --color-accent-hover: #818cf8;
    --color-border: #2a2a2a;
    --color-success: #22c55e;
    --color-warning: #eab308;

    --font-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-mono: 'JetBrains Mono', 'Fira Code', monospace;

    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 2rem;
    --spacing-xl: 4rem;

    --max-width: 800px;
    --header-height: 60px;
}

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

body {
    font-family: var(--font-sans);
    background-color: var(--color-bg);
    color: var(--color-text);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    line-height: 1.3;
    font-weight: 600;
    margin-bottom: var(--spacing-md);
}

h1 { font-size: 2rem; }
h2 { font-size: 1.5rem; }
h3 { font-size: 1.25rem; }

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

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

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

code {
    font-family: var(--font-mono);
    background-color: var(--color-bg-secondary);
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: 4px;
    font-size: 0.9em;
}

pre {
    background-color: var(--color-bg-secondary);
    padding: var(--spacing-md);
    border-radius: 8px;
    overflow-x: auto;
    margin-bottom: var(--spacing-md);
}

pre code {
    display: block;
    background: none;
    margin: 0;
    padding: 0;
    line-height: 1.5;
}

/* Header */
.site-header {
    height: var(--header-height);
    border-bottom: 1px solid var(--color-border);
    position: sticky;
    top: 0;
    background-color: var(--color-bg);
    z-index: 100;
}

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

.site-logo {
    font-weight: 700;
    font-size: 1.25rem;
    color: var(--color-text);
}

.logo-short {
    display: none;
}

.logo-full {
    display: inline;
}

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

.nav-links a {
    color: var(--color-text-muted);
    padding: var(--spacing-xs) 0;
    border-bottom: 2px solid transparent;
    transition: color 0.2s, border-color 0.2s;
}

.nav-links a:hover {
    color: var(--color-text);
}

.nav-links a.active {
    color: var(--color-accent);
    border-bottom-color: var(--color-accent);
}

/* Main content */
.main-content {
    flex: 1;
    max-width: var(--max-width);
    margin: 0 auto;
    padding: var(--spacing-xl) var(--spacing-md);
    width: 100%;
}

/* Hero section */
.hero {
    padding: var(--spacing-xl) 0;
    text-align: center;
    border-bottom: 1px solid var(--color-border);
    background:
        linear-gradient(to bottom, var(--color-bg), transparent 15%),
        radial-gradient(ellipse 100% 70% at 50% -10%, rgba(99, 102, 241, 0.18), transparent 60%);
}

.hero-title {
    font-size: 2.25rem;
    font-weight: 500;
    letter-spacing: -0.02em;
    margin-bottom: var(--spacing-sm);
}

.hero-title .accent {
    color: var(--color-accent);
    font-weight: 400;
}

.hero-subtitle {
    color: var(--color-text-muted);
    font-size: 1.05rem;
    margin: 0;
}

/* Sections */
.section {
    margin-top: var(--spacing-xl);
}

.section h2 {
    margin-bottom: var(--spacing-lg);
}

/* Post list */
.post-list {
    list-style: none;
}

.post-item {
    padding: var(--spacing-lg) 0;
    border-bottom: 1px solid var(--color-border);
}

.post-item:first-child {
    padding-top: 0;
}

.post-item h2, .post-item h3 {
    margin-bottom: var(--spacing-sm);
}

.post-item a {
    color: var(--color-text);
}

.post-item a:hover h2,
.post-item a:hover h3 {
    color: var(--color-accent);
}

.post-description {
    color: var(--color-text-muted);
    margin-bottom: var(--spacing-sm);
}

.post-meta {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    color: var(--color-text-muted);
    font-size: 0.9rem;
}

.reading-time {
    color: var(--color-text-muted);
}

.reading-time::before {
    content: "·";
    margin-right: var(--spacing-sm);
}

/* Post with cover image */
.post-item.has-cover {
    display: grid;
    grid-template-columns: 180px 1fr;
    gap: var(--spacing-lg);
    align-items: start;
}

.post-cover {
    display: block;
    border-radius: 8px;
    overflow: hidden;
    aspect-ratio: 16 / 10;
}

.post-cover {
    background: linear-gradient(135deg, var(--color-bg-secondary) 0%, var(--color-accent) 100%);
    background-size: cover;
}

.post-cover img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.3s;
}

.post-cover img[data-failed="true"] {
    display: none;
}

.post-cover:hover img {
    transform: scale(1.05);
}

.post-content {
    display: block;
}

@media (max-width: 640px) {
    .post-item.has-cover {
        grid-template-columns: 1fr;
    }

    .post-cover {
        aspect-ratio: 16 / 9;
    }
}

/* Tags */
.tag-list {
    display: flex;
    gap: var(--spacing-sm);
    list-style: none;
    flex-wrap: wrap;
    margin-top: var(--spacing-sm);
}

.tag {
    background-color: var(--color-bg-secondary);
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: 4px;
    font-size: 0.8rem;
    color: var(--color-text-muted);
}

/* Project grid */
.project-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: var(--spacing-lg);
    list-style: none;
}

.project-card {
    background-color: var(--color-bg-secondary);
    border-radius: 8px;
    overflow: hidden;
    border: 1px solid var(--color-border);
    transition: border-color 0.2s;
}

.project-card article {
    padding: var(--spacing-lg);
}

.project-card article:has(.project-cover) {
    padding-top: 0;
}

.project-card article .project-cover {
    margin: 0 calc(-1 * var(--spacing-lg));
    margin-bottom: var(--spacing-lg);
}

.project-cover {
    display: block;
    aspect-ratio: 16 / 9;
    overflow: hidden;
    background: linear-gradient(135deg, var(--color-bg-secondary) 0%, var(--color-accent) 100%);
}

.project-cover img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.3s;
}

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

.project-info {
    display: block;
    padding: var(--spacing-lg);
}

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


.project-card h2, .project-card h3 {
    font-size: 1.25rem;
    margin-bottom: var(--spacing-sm);
}

.project-card a {
    color: var(--color-text);
}

.project-description {
    color: var(--color-text-muted);
    font-size: 0.9rem;
    margin-bottom: var(--spacing-md);
}

.project-meta {
    display: flex;
    gap: var(--spacing-md);
    align-items: center;
}

.project-meta {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    flex-wrap: wrap;
}

.project-status {
    font-size: 0.9rem;
    padding: 0.25em 0.6em;
    border-radius: 4px;
    background-color: var(--color-bg);
}

.project-tags {
    display: flex;
    gap: 0.4rem;
    flex-wrap: wrap;
}

.project-tags .tag {
    font-size: 0.75rem;
    padding: 0.15em 0.5em;
    border-radius: 3px;
    background-color: var(--color-surface);
    color: var(--color-text-muted);
}

.github-link,
.demo-link {
    color: var(--color-accent);
}

.status-active {
    color: var(--color-success);
}

.status-completed {
    color: var(--color-accent);
}

.status-archived {
    color: var(--color-text-muted);
}

.status-planned {
    color: var(--color-warning);
}

/* Blog post */
.blog-post {
    max-width: 100%;
}

.post-header {
    margin-bottom: var(--spacing-lg);
    padding-bottom: var(--spacing-lg);
    border-bottom: 1px solid var(--color-border);
}

.post-hero {
    margin: 0 0 var(--spacing-xl) 0;
    border-radius: 12px;
    overflow: hidden;
    aspect-ratio: 21 / 9;
    background: linear-gradient(135deg, var(--color-bg-secondary) 0%, var(--color-accent) 100%);
}

.post-hero img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    object-position: center;
}

.post-content {
    font-size: 1rem;
}

.post-content h2 {
    margin-top: var(--spacing-lg);
}

.post-content h3 {
    margin-top: var(--spacing-md);
}

.post-content img {
    max-width: 100%;
    border-radius: 8px;
    margin: var(--spacing-lg) 0;
}

.post-content blockquote {
    border-left: 3px solid var(--color-accent);
    padding-left: var(--spacing-md);
    color: var(--color-text-muted);
    margin: var(--spacing-lg) 0;
}

.post-content hr {
    border: none;
    border-top: 1px solid var(--color-border);
    margin: var(--spacing-xl) 0;
}

.post-content ul, .post-content ol {
    margin-left: var(--spacing-lg);
    margin-bottom: var(--spacing-md);
}

.post-content table {
    width: 100%;
    border-collapse: collapse;
    margin: var(--spacing-lg) 0;
    font-size: 0.95rem;
}

.post-content th,
.post-content td {
    padding: var(--spacing-sm) var(--spacing-md);
    border: 1px solid var(--color-border);
    text-align: left;
}

.post-content th {
    background-color: var(--color-bg-secondary);
    font-weight: 600;
    color: var(--color-text);
}

.post-content tr:hover {
    background-color: rgba(255, 255, 255, 0.02);
}

.post-content code {
    font-size: 0.85em;
}

/* Mermaid diagrams */
pre.mermaid {
    background: var(--color-bg-secondary);
    border: 1px solid var(--color-border);
    border-radius: 8px;
    padding: var(--spacing-lg);
    margin: var(--spacing-lg) 0;
    overflow-x: auto;
    text-align: center;
}

pre.mermaid svg {
    max-width: 100%;
    height: auto;
    min-height: 200px;
    display: inline-block;
}

pre.mermaid .node rect,
pre.mermaid .node polygon,
pre.mermaid .node circle {
    stroke-width: 2px;
}

pre.mermaid .edgeLabel {
    font-size: 14px;
}

.post-footer, .project-footer {
    margin-top: var(--spacing-xl);
    padding-top: var(--spacing-lg);
    border-top: 1px solid var(--color-border);
}

.share-buttons {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-lg);
}

.share-label {
    color: var(--color-text-muted);
    font-size: 0.9rem;
}

.share-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 36px;
    height: 36px;
    border-radius: 8px;
    background-color: var(--color-bg-secondary);
    color: var(--color-text-muted);
    transition: background-color 0.2s, color 0.2s;
}

.share-btn:hover {
    color: white;
}

.share-twitter:hover {
    background-color: #1da1f2;
}

.share-linkedin:hover {
    background-color: #0a66c2;
}

.share-telegram:hover {
    background-color: #0088cc;
}

.back-link {
    color: var(--color-text-muted);
}

/* Buttons */
.btn {
    display: inline-block;
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: 6px;
    font-size: 0.9rem;
    font-weight: 500;
    transition: background-color 0.2s;
}

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

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

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

.btn-demo:hover {
    background-color: var(--color-accent-hover);
    color: white;
}

.view-all {
    display: inline-block;
    margin-top: var(--spacing-lg);
    color: var(--color-text-muted);
}

/* Empty state */
.empty-state {
    text-align: center;
    color: var(--color-text-muted);
    padding: var(--spacing-xl) 0;
}

/* About page */
.about-page section {
    margin-bottom: var(--spacing-xl);
}

.about-page ul {
    margin-left: var(--spacing-lg);
}

/* Resume page */
.resume-page {
    max-width: 100%;
}

.resume-header {
    text-align: center;
    margin-bottom: var(--spacing-xl);
}

.resume-title {
    font-size: 1.25rem;
    color: var(--color-text-muted);
    margin-bottom: var(--spacing-sm);
}

.resume-contact {
    color: var(--color-text-muted);
}

.resume-section {
    margin-bottom: var(--spacing-xl);
}

.resume-section h2 {
    margin-bottom: var(--spacing-lg);
    padding: var(--spacing-sm) 0;
    border-top: 1px solid var(--color-border);
    border-bottom: 1px solid var(--color-border);
}

.summary-list {
    list-style: none;
    padding: 0;
}

.summary-list li {
    position: relative;
    padding-left: var(--spacing-lg);
    margin-bottom: var(--spacing-sm);
    line-height: 1.6;
}

.summary-list li::before {
    content: "—";
    position: absolute;
    left: 0;
    color: var(--color-accent);
}

.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
    gap: var(--spacing-lg);
}

.skill-category h3 {
    font-size: 1rem;
    color: var(--color-accent);
    margin-bottom: var(--spacing-sm);
}

.skill-category ul {
    list-style: none;
}

.skill-category li {
    color: var(--color-text-muted);
    padding: var(--spacing-xs) 0;
}

.experience-item {
    margin-bottom: var(--spacing-lg);
    padding-bottom: var(--spacing-lg);
    border-bottom: 1px solid var(--color-border);
}

.experience-item:last-child {
    border-bottom: none;
}

.experience-header {
    display: flex;
    justify-content: space-between;
    align-items: baseline;
    flex-wrap: wrap;
    gap: var(--spacing-sm);
}

.experience-header h3 {
    margin-bottom: 0;
}

.experience-location {
    color: var(--color-text-muted);
    font-size: 0.9rem;
}

.experience-role {
    color: var(--color-accent);
    font-weight: 500;
    margin-bottom: var(--spacing-xs);
}

.experience-dates {
    color: var(--color-text-muted);
    font-size: 0.9rem;
    margin-bottom: var(--spacing-sm);
}

.experience-item ul {
    margin-left: var(--spacing-lg);
}

.experience-item li {
    margin-bottom: var(--spacing-xs);
}

.education-item h3 {
    margin-bottom: var(--spacing-xs);
}

.education-degree {
    color: var(--color-accent);
    font-weight: 500;
    margin-bottom: var(--spacing-xs);
}

.education-details {
    color: var(--color-text-muted);
    font-size: 0.9rem;
    margin-bottom: var(--spacing-xs);
}

.education-dates {
    color: var(--color-text-muted);
}

.experience-tech {
    color: var(--color-text-muted);
    font-size: 0.85rem;
    font-style: italic;
    margin-top: var(--spacing-sm);
    padding-top: var(--spacing-sm);
    border-top: 1px dashed var(--color-border);
}

.experience-earlier {
    opacity: 0.8;
}

.experience-earlier p {
    color: var(--color-text-muted);
}

.cert-issuer {
    color: var(--color-text-muted);
    font-size: 0.9rem;
}

/* Contact page */
.contact-page {
    max-width: 600px;
    margin: 0 auto;
}

.contact-form {
    margin-top: var(--spacing-lg);
}

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

.form-group label {
    display: block;
    margin-bottom: var(--spacing-sm);
    font-weight: 500;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: var(--spacing-sm) var(--spacing-md);
    border: 1px solid var(--color-border);
    border-radius: 6px;
    background-color: var(--color-bg-secondary);
    color: var(--color-text);
    font-family: inherit;
    font-size: 1rem;
}

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

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

.form-group .error {
    color: #ef4444;
    font-size: 0.875rem;
    margin-top: var(--spacing-xs);
}

.btn-submit {
    background-color: var(--color-accent);
    color: white;
    padding: var(--spacing-sm) var(--spacing-lg);
    border: none;
    border-radius: 6px;
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: background-color 0.2s;
}

.btn-submit:hover {
    background-color: var(--color-accent-hover);
}

.btn-submit:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

.form-success {
    background-color: rgba(34, 197, 94, 0.1);
    border: 1px solid var(--color-success);
    border-radius: 8px;
    padding: var(--spacing-lg);
    text-align: center;
}

.form-success h2 {
    color: var(--color-success);
}

.honeypot {
    position: absolute;
    left: -9999px;
}

/* Back to top button */
.back-to-top {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    width: 44px;
    height: 44px;
    background-color: var(--color-bg-secondary);
    border: 1px solid var(--color-border);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--color-text-muted);
    text-decoration: none;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.3s, visibility 0.3s, background-color 0.2s;
    z-index: 50;
}

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

.back-to-top:hover {
    background-color: var(--color-accent);
    border-color: var(--color-accent);
    color: white;
}

/* Footer */
.site-footer {
    border-top: 1px solid var(--color-border);
    padding: var(--spacing-lg) var(--spacing-md);
    margin-top: auto;
}

.footer-container {
    max-width: var(--max-width);
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    color: var(--color-text-muted);
    font-size: 0.9rem;
}

.footer-links {
    display: flex;
    gap: var(--spacing-md);
}

.footer-links a {
    color: var(--color-text-muted);
}

.version {
    opacity: 0.6;
}

/* Responsive */
@media (max-width: 640px) {
    h1 { font-size: 1.75rem; }
    h2 { font-size: 1.25rem; }

    .logo-full {
        display: none;
    }

    .logo-short {
        display: inline;
    }

    .nav-links {
        gap: var(--spacing-sm);
    }

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

    .footer-container {
        flex-direction: column;
        gap: var(--spacing-md);
        text-align: center;
    }
}