/* ============================================
   CSS Custom Properties (Theme Variables)
   ============================================ */
:root {
    /* Light Theme */
    --color-bg-primary: #ffffff;
    --color-bg-secondary: #f8f9fa;
    --color-bg-tertiary: #f1f3f5;
    --color-bg-code: #f1f3f5;
    
    --color-text-primary: #212529;
    --color-text-secondary: #495057;
    --color-text-tertiary: #868e96;
    --color-text-link: #1c7ed6;
    --color-text-link-hover: #1971c2;
    
    --color-border: #dee2e6;
    --color-border-light: #e9ecef;
    
    --color-accent: #1c7ed6;
    --color-accent-hover: #1971c2;
    
    --color-tag-bg: #e7f5ff;
    --color-tag-text: #1864ab;
    
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.07);
    
    --transition-speed: 0.2s;
}

/* Dark Theme */
[data-theme="dark"] {
    --color-bg-primary: #1a1b1e;
    --color-bg-secondary: #242529;
    --color-bg-tertiary: #2c2d31;
    --color-bg-code: #2c2d31;
    
    --color-text-primary: #e4e5e7;
    --color-text-secondary: #b0b1b3;
    --color-text-tertiary: #8a8b8d;
    --color-text-link: #74c0fc;
    --color-text-link-hover: #66b3f7;
    
    --color-border: #3b3c40;
    --color-border-light: #2c2d31;
    
    --color-accent: #74c0fc;
    --color-accent-hover: #66b3f7;
    
    --color-tag-bg: #1c3a5f;
    --color-tag-text: #74c0fc;
    
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.4);
}

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

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    line-height: 1.7;
    color: var(--color-text-primary);
    background-color: var(--color-bg-primary);
    transition: background-color var(--transition-speed), color var(--transition-speed);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

#main-content {
    flex: 1;
}

/* Skip link for accessibility */
.skip-link {
    position: absolute;
    top: -100px;
    left: 50%;
    transform: translateX(-50%);
    background: var(--color-accent);
    color: white;
    padding: 8px 16px;
    z-index: 100;
    transition: top 0.2s;
    border-radius: 0 0 6px 6px;
    text-decoration: none;
    font-weight: 500;
}

.skip-link:focus {
    top: 0;
}

.skip-link:not(:focus) {
    opacity: 0;
    pointer-events: none;
}

a {
    color: var(--color-text-link);
    text-decoration: none;
    transition: color var(--transition-speed);
}

a:hover {
    color: var(--color-text-link-hover);
}

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

/* ============================================
   Typography
   ============================================ */
h1, h2, h3, h4, h5, h6 {
    line-height: 1.3;
    font-weight: 600;
    color: var(--color-text-primary);
    margin-bottom: 1rem;
}

h1 { font-size: 2.5rem; }
h2 { font-size: 2rem; }
h3 { font-size: 1.5rem; }
h4 { font-size: 1.25rem; }
h5 { font-size: 1.125rem; }
h6 { font-size: 1rem; }

p {
    margin-bottom: 1.25rem;
    color: var(--color-text-secondary);
}

strong, b {
    font-weight: 600;
}

code {
    font-family: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
    font-size: 0.9em;
    background-color: var(--color-bg-code);
    padding: 0.2em 0.4em;
    border-radius: 3px;
}

pre {
    background-color: var(--color-bg-code);
    padding: 1rem 1.5rem;
    border-radius: 6px;
    overflow-x: auto;
    margin-bottom: 1.5rem;
    border: 1px solid var(--color-border-light);
}

pre code {
    background: none;
    padding: 0;
    font-size: 0.875rem;
    line-height: 1.6;
}

blockquote {
    border-left: 4px solid var(--color-accent);
    padding-left: 1.5rem;
    margin: 1.5rem 0;
    color: var(--color-text-secondary);
    font-style: italic;
}

blockquote p:last-child {
    margin-bottom: 0;
}

hr {
    border: none;
    border-top: 1px solid var(--color-border);
    margin: 2rem 0;
}

/* ============================================
   Layout
   ============================================ */
.container {
    max-width: 960px;
    margin: 0 auto;
    padding: 0 1.5rem;
}

/* Optimal reading width for content */
.post-content, .page-content, .resume-body {
    max-width: 720px;
    margin: 0 auto;
}

/* ============================================
   Site Header
   ============================================ */
.site-header {
    background-color: var(--color-bg-primary);
    border-bottom: 1px solid var(--color-border);
    position: sticky;
    top: 0;
    z-index: 50;
    transition: background-color var(--transition-speed), border-color var(--transition-speed);
}

.navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.75rem 0;
}

.site-title {
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--color-text-primary);
    text-decoration: none;
}

.site-title:hover {
    color: var(--color-text-primary);
}

.nav-links {
    display: flex;
    align-items: center;
    gap: 1.5rem;
}

.nav-link {
    color: var(--color-text-secondary);
    font-weight: 500;
    text-decoration: none;
    padding: 0.5rem 0;
    position: relative;
}

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

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

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

/* ============================================
   Theme Toggle
   ============================================ */
.theme-toggle {
    background: none;
    border: 1px solid var(--color-border);
    border-radius: 50%;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    color: var(--color-text-secondary);
    transition: all var(--transition-speed);
}

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

.theme-toggle .icon {
    width: 20px;
    height: 20px;
}

.theme-toggle .sun-icon {
    display: none;
}

.theme-toggle .moon-icon {
    display: block;
}

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

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

/* ============================================
   Homepage / Bio Section
   ============================================ */
.home {
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 4rem 0 5rem;
}

.bio-section {
    text-align: center;
    max-width: 680px;
    margin: 0 auto;
}

.bio-photo {
    margin: 0 auto 1.75rem;
    display: flex;
    justify-content: center;
}

.profile-image {
    display: block;
    width: 180px;
    height: 180px;
    max-width: none;
    border-radius: 50%;
    object-fit: cover;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.profile-image:hover {
    transform: scale(1.02);
    box-shadow: 0 6px 20px rgba(0, 0, 0, 0.12);
}

.bio-name {
    font-size: 2.25rem;
    margin-bottom: 0.35rem;
    color: var(--color-text-primary);
}

.bio-role {
    font-size: 1.125rem;
    color: var(--color-text-tertiary);
    margin-bottom: 2rem;
    font-weight: 400;
}

.bio-description {
    color: var(--color-text-secondary);
    margin-bottom: 1.25rem;
    line-height: 1.75;
    font-size: 1.05rem;
}

.bio-interests {
    color: var(--color-text-tertiary);
    line-height: 1.75;
    font-size: 1.025rem;
    margin-bottom: 0;
}

/* ============================================
   Buttons
   ============================================ */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.625rem 1.25rem;
    border-radius: 6px;
    font-weight: 500;
    font-size: 0.95rem;
    text-decoration: none;
    transition: all var(--transition-speed);
    cursor: pointer;
    border: none;
}

.btn-primary {
    background-color: var(--color-accent);
    color: #ffffff;
}

.btn-primary:hover {
    background-color: var(--color-accent-hover);
    color: #ffffff;
}

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

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

/* ============================================
   Posts List
   ============================================ */

.recent-posts {
    padding: 2.5rem 0;
}

.recent-posts h2 {
    margin-bottom: 1.5rem;
    font-size: 1.35rem;
}

.view-all {
    margin-top: 1.5rem;
}

.view-all a {
    font-weight: 500;
    font-size: 0.95rem;
}

.posts-list {
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

.post-preview {
    padding-bottom: 2rem;
    border-bottom: 1px solid var(--color-border-light);
}

.post-preview:last-child {
    border-bottom: none;
    padding-bottom: 0;
}

.post-preview h3 {
    font-size: 1.2rem;
    margin-bottom: 0.35rem;
}

.post-preview h3 a {
    color: var(--color-text-primary);
}

.post-preview h3 a:hover {
    color: var(--color-text-link);
}

.post-meta {
    display: flex;
    align-items: center;
    gap: 1rem;
    color: var(--color-text-tertiary);
    font-size: 0.85rem;
    margin-bottom: 0.75rem;
}

.excerpt {
    color: var(--color-text-secondary);
    margin-bottom: 0;
    font-size: 0.95rem;
}

.post-summary {
    padding-bottom: 2rem;
    border-bottom: 1px solid var(--color-border-light);
}

.post-summary:last-child {
    border-bottom: none;
}

.post-header {
    margin-bottom: 1rem;
}

.post-title {
    font-size: 1.5rem;
    margin-bottom: 0.5rem;
}

.post-title a {
    color: var(--color-text-primary);
    text-decoration: none;
}

.post-title a:hover {
    color: var(--color-text-link);
}

.post-summary .post-meta {
    display: flex;
    align-items: center;
    gap: 1rem;
    color: var(--color-text-tertiary);
    font-size: 0.85rem;
    flex-wrap: wrap;
}

.post-summary .post-meta time {
    white-space: nowrap;
}

.post-summary .post-categories a,
.post-summary .post-tags a {
    color: var(--color-text-tertiary);
}

.post-summary .post-categories a:hover,
.post-summary .post-tags a:hover {
    color: var(--color-text-link);
}

.post-summary .post-excerpt {
    color: var(--color-text-secondary);
    margin-bottom: 1rem;
}

.post-summary .post-excerpt p {
    margin-bottom: 0.5rem;
}

.post-summary .read-more {
    font-weight: 500;
    font-size: 0.95rem;
}

.post-summary .post-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.tag {
    display: inline-block;
    background-color: var(--color-tag-bg);
    color: var(--color-tag-text);
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 500;
    text-decoration: none;
}

.tag:hover {
    opacity: 0.85;
}

.no-posts {
    text-align: center;
    color: var(--color-text-tertiary);
    padding: 3rem 0;
}

/* ============================================
   Pagination
   ============================================ */
.pagination {
    margin-top: 3rem;
    padding-top: 2rem;
    border-top: 1px solid var(--color-border);
}

.pagination-list {
    display: flex;
    justify-content: space-between;
    list-style: none;
    gap: 1rem;
}

.pagination-link {
    display: inline-block;
    padding: 0.625rem 1.25rem;
    background-color: var(--color-bg-secondary);
    border: 1px solid var(--color-border);
    border-radius: 6px;
    color: var(--color-text-primary);
    font-weight: 500;
    transition: all var(--transition-speed);
}

.pagination-link:hover {
    border-color: var(--color-accent);
    color: var(--color-accent);
    background-color: var(--color-bg-tertiary);
}

/* ============================================
   Single Post
   ============================================ */
.post-single {
    padding: 3rem 0;
}

.post-header-single {
    margin-bottom: 3rem;
    padding-bottom: 2rem;
    border-bottom: 1px solid var(--color-border);
}

.post-header-single h1 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    line-height: 1.2;
}

.post-header-single .post-meta {
    margin-bottom: 1rem;
}

.reading-time {
    color: var(--color-text-tertiary);
    font-size: 0.9rem;
}

.post-content {
    margin-bottom: 3rem;
}

.post-content h2 {
    margin-top: 3rem;
    margin-bottom: 1rem;
    padding-bottom: 0.5rem;
    border-bottom: 1px solid var(--color-border-light);
}

.post-content h3 {
    margin-top: 2rem;
}

.post-content p {
    font-size: 1.05rem;
}

.post-content ul, .post-content ol {
    margin-bottom: 1.25rem;
    padding-left: 2rem;
    color: var(--color-text-secondary);
}

.post-content li {
    margin-bottom: 0.5rem;
}

.post-content a {
    text-decoration: underline;
    text-underline-offset: 2px;
}

.post-content img {
    margin: 2rem 0;
    border-radius: 6px;
}

.post-content table {
    width: 100%;
    margin-bottom: 1.5rem;
    border-collapse: collapse;
}

.post-content table th,
.post-content table td {
    padding: 0.75rem;
    border: 1px solid var(--color-border);
    text-align: left;
}

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

.post-footer {
    margin-top: 3rem;
    padding-top: 2rem;
    border-top: 1px solid var(--color-border);
}

.post-navigation {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
}

.nav-prev, .nav-next {
    display: flex;
    flex-direction: column;
    padding: 1rem;
    border-radius: 6px;
    border: 1px solid var(--color-border);
    text-decoration: none;
    transition: all var(--transition-speed);
}

.nav-prev:hover, .nav-next:hover {
    border-color: var(--color-accent);
    background-color: var(--color-bg-secondary);
}

.nav-prev {
    align-items: flex-start;
}

.nav-next {
    align-items: flex-end;
    text-align: right;
}

.nav-label {
    font-size: 0.85rem;
    color: var(--color-text-tertiary);
    margin-bottom: 0.25rem;
}

.nav-title {
    font-weight: 500;
    color: var(--color-text-primary);
}

/* ============================================
   Taxonomy Pages (Categories & Tags)
   ============================================ */
.taxonomy-listing, .terms-listing {
    padding: 3rem 0;
}

.taxonomy-listing h1, .terms-listing h1 {
    margin-bottom: 2rem;
}

.taxonomy-items {
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
}

.taxonomy-item a {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem 1.25rem;
    background-color: var(--color-bg-secondary);
    border: 1px solid var(--color-border);
    border-radius: 6px;
    text-decoration: none;
    color: var(--color-text-primary);
    font-weight: 500;
    transition: all var(--transition-speed);
}

.taxonomy-item a:hover {
    border-color: var(--color-accent);
    color: var(--color-accent);
}

.taxonomy-count {
    color: var(--color-text-tertiary);
    font-size: 0.85rem;
}

/* Tag Cloud */
.terms-cloud {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
}

.term-tag {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    background-color: var(--color-bg-secondary);
    border: 1px solid var(--color-border);
    border-radius: 20px;
    text-decoration: none;
    color: var(--color-text-primary);
    font-weight: 500;
    transition: all var(--transition-speed);
}

.term-tag:hover {
    border-color: var(--color-accent);
    color: var(--color-accent);
}

.term-count {
    background-color: var(--color-tag-bg);
    color: var(--color-tag-text);
    padding: 0.125rem 0.5rem;
    border-radius: 10px;
    font-size: 0.75rem;
}

/* ============================================
   Page Templates
   ============================================ */
.page-single {
    padding: 3rem 0;
}

.page-content h1 {
    margin-bottom: 2rem;
}

/* Resume Page */
.resume-content {
    max-width: 800px;
}

.resume-body h2 {
    margin-top: 2.5rem;
    margin-bottom: 1rem;
    padding-bottom: 0.5rem;
    border-bottom: 2px solid var(--color-border);
}

.resume-body h3 {
    margin-top: 1.5rem;
}

.resume-body ul {
    margin-bottom: 1rem;
}

.resume-actions {
    margin-top: 3rem;
    padding-top: 2rem;
    border-top: 1px solid var(--color-border);
    display: flex;
    justify-content: center;
}

/* ============================================
   Error Page
   ============================================ */
.error-page {
    padding: 6rem 0;
    text-align: center;
}

.error-content h1 {
    font-size: 6rem;
    font-weight: 700;
    color: var(--color-accent);
    margin-bottom: 1rem;
}

.error-content h2 {
    font-size: 1.5rem;
    margin-bottom: 1rem;
}

.error-content p {
    margin-bottom: 2rem;
}

/* ============================================
   Site Footer
   ============================================ */
.site-footer {
    background-color: var(--color-bg-secondary);
    border-top: 1px solid var(--color-border);
    padding: 1.5rem 0;
    margin-top: auto;
    transition: background-color var(--transition-speed), border-color var(--transition-speed);
}

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

.copyright {
    color: var(--color-text-tertiary);
    font-size: 0.85rem;
    margin: 0;
}

.footer-right {
    display: flex;
    align-items: center;
    gap: 0.35rem;
}

.social-links {
    display: inline-flex;
    gap: 0.5rem;
    align-items: center;
}

.social-links a {
    color: var(--color-text-tertiary);
    display: flex;
    align-items: center;
    justify-content: center;
    width: 32px;
    height: 32px;
    border-radius: 50%;
    transition: all var(--transition-speed);
}

.social-links a:hover {
    color: var(--color-accent);
    background-color: var(--color-bg-tertiary);
}

.social-links svg {
    width: 18px;
    height: 18px;
}

.rss-link {
    color: var(--color-text-tertiary);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 32px;
    height: 32px;
    border-radius: 50%;
    transition: all var(--transition-speed);
}

.rss-link:hover {
    color: var(--color-accent);
    background-color: var(--color-bg-tertiary);
}

.rss-link svg {
    width: 16px;
    height: 16px;
}

/* ============================================
   Responsive Design
   ============================================ */
@media (max-width: 768px) {
    html {
        font-size: 15px;
    }
    
    .bio-name {
        font-size: 1.75rem;
    }
    
    .bio-role {
        font-size: 1rem;
        margin-bottom: 1.5rem;
    }
    
    .bio-description,
    .bio-interests {
        font-size: 0.95rem;
        line-height: 1.65;
    }
    
    .profile-image {
        width: 140px;
        height: 140px;
    }
    
    .home {
        padding: 2.5rem 0 3rem;
    }
    
    .post-navigation {
        grid-template-columns: 1fr;
    }
    
    .nav-prev, .nav-next {
        align-items: flex-start;
        text-align: left;
    }
    
    .post-header-single h1 {
        font-size: 1.5rem;
    }
    
    .post-header-single .post-meta {
        flex-direction: column;
        align-items: flex-start;
        gap: 0.5rem;
    }
}

@media (max-width: 480px) {
    html {
        font-size: 14px;
    }
    
    .container {
        padding: 0 1rem;
    }
    
    .navbar {
        flex-direction: row;
        gap: 0;
    }
    
    .nav-links {
        gap: 0.75rem;
    }
    
    .nav-link {
        font-size: 0.9rem;
    }
    
    .theme-toggle {
        width: 34px;
        height: 34px;
    }
    
    .theme-toggle .icon {
        width: 16px;
        height: 16px;
    }
    
    .bio-section {
        max-width: 100%;
    }
    
    .bio-name {
        font-size: 1.5rem;
    }
    
    .profile-image {
        width: 120px;
        height: 120px;
    }
    
    .home {
        padding: 2rem 0 2.5rem;
    }
    
    .footer-content {
        flex-direction: column;
        gap: 0.75rem;
        text-align: center;
    }
    
    .footer-right {
        justify-content: center;
    }
}

/* ============================================
   Print Styles (for Resume)
   ============================================ */
@media print {
    .site-header, .site-footer, .theme-toggle, .resume-actions {
        display: none !important;
    }
    
    body {
        background: white;
        color: black;
    }
    
    a {
        color: black;
    }
    
    .container {
        max-width: 100%;
    }
}