/* Light/Dark Mode Variables */
:root {
    --bg-main: #f8f9fa;
    --bg-card: #ffffff;
    --bg-card-alt: #f8f9fa;
    --bg-nav: rgba(255,255,255,0.95);
    --text-primary: #2c3e50;
    --text-secondary: #555;
    --text-muted: #666;
    --text-faint: #999;
    --text-hero: #050f19;
    --border-color: #eee;
    --tag-bg: #e3f2fd;
    --tag-color: #1a73e8;
    --social-bg: #f0f0f0;
    --social-color: var(--text-secondary);
    --accent: #3498db;
    --shadow: rgba(0,0,0,0.08);
    --toggle-bg: #e0e0e0;
    --toggle-icon: '☀️';
}

[data-theme="dark"] {
    --bg-main: #0f1117;
    --bg-card: #1a1d27;
    --bg-card-alt: #13161f;
    --bg-nav: rgba(15,17,23,0.97);
    --text-primary: #e2e8f0;
    --text-secondary: #a0aec0;
    --text-muted: #8896a5;
    --text-faint: #6b7280;
    --text-hero: #e2e8f0;
    --border-color: #2d3748;
    --tag-bg: #1e3a5f;
    --tag-color: #63b3ed;
    --social-bg: #2d3748;
    --social-color: #a0aec0;
    --accent: #63b3ed;
    --shadow: rgba(0,0,0,0.3);
    --toggle-bg: #3498db;
    --toggle-icon: '🌙';
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    line-height: 1.6;
    color: #ffffff;
    background: var(--bg-main);
}

/* Hero Section */
.hero {
    padding: 3rem 2rem 0.5rem;
    background: transparent;
    max-width: 1200px;
    margin: 0 auto;
}

.hero-header {
    margin-bottom: 1.5rem;
}

.hero-title-section {
    display: flex;
    flex-direction: column;
    margin-bottom: 1rem;
}

.hero h1 {
    font-size: 1.2rem;
    margin: 0;
    color: var(--text-hero);
    font-weight: 600;
}

.hero .subtitle {
    font-size: 0.95rem;
    color: var(--text-muted);
    margin: 0;
    font-weight: 400;
}

/* Navigation */
nav {
    display: flex;
    align-items: center;
}

nav .container {
    padding: 0;
    display: flex;
    justify-content: space-between;
    align-items: center;
    width: 100%;
}

nav ul {
    list-style: none;
    display: flex;
    gap: 2rem;
    margin: 0;
    padding: 0;
}

nav a {
    text-decoration: none;
    color: var(--text-secondary);
    transition: color 0.3s;
    font-size: 0.95rem;
}

nav a:hover {
    color: #3498db;
}

.social-links {
    display: flex;
    gap: 1rem;
    align-items: center;
}

.social-links a {
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    background: var(--social-bg);
    color: var(--text-secondary);
    transition: all 0.3s;
    font-size: 1rem;
}

.social-links a:hover {
    background: var(--accent);
    color: white;
    transform: translateY(-2px);
}

/* About Me Section */
.about-me {
    background: transparent;
    padding: 1rem 2rem 2rem;
    max-width: 1200px;
    margin: 0 auto;
}

.about-me-content {
    max-width: 100%;
}

.about-me p {
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: 1rem;
    text-align: left;
}

.about-layout {
    display: flex;
    gap: 40px;
    align-items: flex-start;
}

.about-photo {
    position: relative;
    width: 220px;
    border-radius: 16px;
    overflow: hidden;
    flex-shrink: 0;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.about-photo img {
    width: 100%;
    display: block;
    border-radius: 16px;
}

.about-photo:hover {
    transform: translateY(-6px);
    box-shadow: 0 14px 35px rgba(0, 0, 0, 0.25);
}

.photo-caption {
    position: absolute;
    bottom: 0;
    width: 100%;
    padding: 10px 0;
    text-align: center;
    font-weight: 600;
    color: white;
    background: linear-gradient(90deg, #3b82f6, #06b6d4);
    opacity: 0;
    transition: opacity 0.3s ease;
}

.about-photo:hover .photo-caption {
    opacity: 1;
}

.about-content {
    flex: 1;
}

/* Section Styles */
section {
    padding: 2rem 2rem 3rem;
    max-width: 1200px;
    margin: 0 auto;
}

h2 {
    font-size: 0.85rem;
    margin-bottom: 1.5rem;
    text-align: center;
    color: var(--text-primary);
    font-weight: 600;
}

/* Projects Section */
.projects {
    background: transparent;
}

.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.project-card {
    background: var(--bg-main);
    border-radius: 10px;
    overflow: hidden;
    transition: transform 0.1s ease-out, box-shadow 0.3s;
    cursor: pointer;
    transform-style: preserve-3d;
    perspective: 1000px;
}

.project-card:hover {
    box-shadow: 0 15px 30px rgba(0,0,0,0.15);
}

.project-video {
    width: 100%;
    height: 200px;
    object-fit: cover;
    display: block;
    border: none;
}

.project-info {
    padding: 1.5rem;
}

.project-info h3 {
    margin-bottom: 0.5rem;
    color: var(--text-primary);
    transition: color 0.3s;
}

.project-info:hover h3 {
    color: #3498db;
}

.project-info p {
    color: var(--text-muted);
    margin-bottom: 1rem;
}

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

.tag {
    padding: 0.25rem 0.75rem;
    background: var(--tag-bg);
    color: var(--tag-color);
    border-radius: 15px;
    font-size: 0.85rem;
}

/* Full Page Sections */
.page-section {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--bg-main);
    z-index: 3000;
    overflow-y: auto;
}

.page-section.active {
    display: block;
}

.page-container {
    max-width: 1000px;
    margin: 0 auto;
    padding: 3rem 2rem;
}

.page-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 3rem;
}

.page-header h1 {
    font-size: 2rem;
    color: var(--text-primary);
}

.close-page {
    background: #2c3e50;
    color: white;
    border: none;
    padding: 0.75rem 1.5rem;
    border-radius: 5px;
    cursor: pointer;
    font-size: 1rem;
    transition: background 0.3s;
}

.close-page:hover {
    background: var(--accent);
}

/* About Me Page */
.about-section {
    background: var(--bg-card);
    padding: 2rem;
    border-radius: 10px;
    box-shadow: 0 5px 15px var(--shadow);
    margin-bottom: 2rem;
}

.about-section h2 {
    font-size: 1.5rem;
    margin-bottom: 1rem;
    text-align: left;
    color: var(--text-primary);
}

.about-section p {
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: 1rem;
}

.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
    margin-top: 1.5rem;
}

.skill-item {
    background: var(--bg-main);
    padding: 1rem;
    border-radius: 8px;
    text-align: center;
}

.skill-item h4 {
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

/* CV Page */
.cv-section {
    background: var(--bg-card);
    padding: 2rem;
    border-radius: 10px;
    box-shadow: 0 5px 15px var(--shadow);
    margin-bottom: 2rem;
}

.cv-section h2 {
    font-size: 1.5rem;
    margin-bottom: 1.5rem;
    text-align: left;
    color: var(--text-primary);
    border-bottom: 2px solid #3498db;
    padding-bottom: 0.5rem;
}

.cv-item {
    margin-bottom: 2rem;
}

.cv-item h3 {
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

.cv-item .cv-meta {
    color: var(--text-faint);
    font-size: 0.9rem;
    margin-bottom: 0.5rem;
}

.cv-item p, .cv-item ul {
    color: var(--text-secondary);
    line-height: 1.8;
}

.cv-item ul {
    margin-left: 1.5rem;
    margin-top: 0.5rem;
}

/* Project Detail Page */
.project-detail {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--bg-main);
    z-index: 3000;
    overflow-y: auto;
}

.project-detail.active {
    display: block;
}

.project-detail-container {
    max-width: 1600px;
    width: 92%;
    margin: 0 auto;
    padding: 3rem 2rem;
}

.project-detail-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
}

.project-detail-header h1 {
    font-size: 2rem;
    color: var(--text-primary);
}

.close-detail {
    background: #2c3e50;
    color: white;
    border: none;
    padding: 0.75rem 1.5rem;
    border-radius: 5px;
    cursor: pointer;
    font-size: 1rem;
    transition: background 0.3s;
}

.close-detail:hover {
    background: var(--accent);
}

.project-detail-content {
    display: grid;
    grid-template-columns: 1.5fr 1fr;
    gap: 3rem;
}

.project-detail-content.no-media {
    display: block;
}

.project-detail-content.no-media .project-detail-info {
    max-width: 100%;
}

.project-detail-video {
    width: 100%;
    aspect-ratio: 16/9;
    background: #000;
    border-radius: 10px;
    overflow: hidden;
    position: sticky;
    top: 24px;
    will-change: transform;
}

.project-detail-video video, .project-detail-video iframe {
    width: 100%;
    height: 100%;
    object-fit: contain;
}

.project-detail-info {
    background: var(--bg-card);
    padding: 2rem;
    border-radius: 10px;
    box-shadow: 0 5px 15px var(--shadow);
}

.project-detail-info h2 {
    font-size: 1.5rem;
    margin-bottom: 1rem;
    text-align: left;
}

.project-detail-info h3 {
    font-size: 1.2rem;
    margin-top: 2rem;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.project-detail-info p {
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: 1rem;
}

.project-detail-info ul {
    list-style: none;
    padding: 0;
}

.project-detail-info li {
    padding: 0.5rem 0;
    color: var(--text-secondary);
    border-bottom: 1px solid var(--border-color);
}

.project-detail-info li:last-child {
    border-bottom: none;
}

/* Blog System */
.blog-page {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--bg-main);
    z-index: 3000;
    overflow-y: auto;
}

.blog-page.active {
    display: block;
}

.blog-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 3rem 2rem;
}

.blog-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 3rem;
}

.blog-header h1 {
    font-size: 2rem;
    color: var(--text-primary);
}

.close-blog {
    background: #2c3e50;
    color: white;
    border: none;
    padding: 0.75rem 1.5rem;
    border-radius: 5px;
    cursor: pointer;
    font-size: 1rem;
    transition: background 0.3s;
}

.close-blog:hover {
    background: var(--accent);
}

.blog-posts {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
    gap: 2rem;
}

.blog-post {
    background: var(--bg-card);
    border-radius: 10px;
    padding: 2rem;
    box-shadow: 0 5px 15px var(--shadow);
    transition: transform 0.3s, box-shadow 0.3s;
    cursor: pointer;
}

.blog-post:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 25px rgba(0,0,0,0.15);
}

.blog-post-date {
    color: var(--text-faint);
    font-size: 0.85rem;
    margin-bottom: 0.5rem;
}

.blog-post h3 {
    color: var(--text-primary);
    margin-bottom: 1rem;
    font-size: 1.3rem;
}

.blog-post-excerpt {
    color: var(--text-secondary);
    line-height: 1.6;
    margin-bottom: 1rem;
}

.blog-post-tags {
    display: flex;
    gap: 0.5rem;
    flex-wrap: wrap;
    margin-top: 1rem;
}

.blog-tag {
    padding: 0.25rem 0.75rem;
    background: var(--tag-bg);
    color: var(--tag-color);
    border-radius: 15px;
    font-size: 0.75rem;
}

/* Blog Post Detail */
.blog-post-detail {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--bg-main);
    z-index: 3001;
    overflow-y: auto;
}

.blog-post-detail.active {
    display: block;
}

.blog-post-container {
    max-width: 800px;
    margin: 0 auto;
    padding: 3rem 2rem;
}

.blog-post-header {
    margin-bottom: 2rem;
}

.blog-post-back {
    background: #2c3e50;
    color: white;
    border: none;
    padding: 0.75rem 1.5rem;
    border-radius: 5px;
    cursor: pointer;
    font-size: 1rem;
    transition: background 0.3s;
    margin-bottom: 2rem;
}

.blog-post-back:hover {
    background: var(--accent);
}

.blog-post-detail h1 {
    font-size: 2.5rem;
    color: var(--text-primary);
    margin-bottom: 1rem;
}

.blog-post-meta {
    color: var(--text-faint);
    margin-bottom: 2rem;
    padding-bottom: 1rem;
    border-bottom: 2px solid var(--border-color);
}

.blog-post-content {
    background: var(--bg-card);
    padding: 3rem;
    border-radius: 10px;
    box-shadow: 0 5px 15px var(--shadow);
}

.blog-post-content h2 {
    font-size: 1.8rem;
    color: var(--text-primary);
    margin: 2rem 0 1rem;
    text-align: left;
}

.blog-post-content h3 {
    font-size: 1.4rem;
    color: var(--text-primary);
    margin: 1.5rem 0 1rem;
}

.blog-post-content p {
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: 1.5rem;
}

.blog-post-content ul, .blog-post-content ol {
    margin-left: 2rem;
    margin-bottom: 1.5rem;
    color: var(--text-secondary);
}

.blog-post-content li {
    margin-bottom: 0.5rem;
    line-height: 1.8;
}

.project-repo-link {
    margin-top: 14px;
    text-align: center;
}

.project-repo-link a {
    display: inline-flex;
    flex-direction: column;
    align-items: center;
    gap: 6px;
    color: #ffffff;
    text-decoration: none;
    opacity: 0.85;
    transition: opacity 0.2s ease, transform 0.2s ease;
}

.project-repo-link a:hover {
    opacity: 1;
    transform: scale(1.05);
}

.repo-title {
    font-size: 0.85rem;
    letter-spacing: 0.04em;
    opacity: 0.9;
}

/* Blog Pagination */
.blog-pagination {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 1rem;
    margin-top: 2rem;
    padding: 1rem;
    grid-column: 1 / -1;
}

.blog-pagination button {
    background: #2c3e50;
    color: white;
    border: none;
    padding: 0.5rem 1rem;
    border-radius: 5px;
    cursor: pointer;
    transition: background 0.3s;
}

.blog-pagination button:hover:not(:disabled) {
    background: var(--accent);
}

.blog-pagination button:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.blog-pagination span {
    color: var(--text-muted);
}

.no-posts {
    text-align: center;
    padding: 2rem;
    color: var(--text-muted);
    font-style: italic;
    grid-column: 1 / -1;
}

/* Responsive */
@media (max-width: 968px) {
    .project-detail-content {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 900px) {
    .about-layout {
        flex-direction: column;
    }

    .about-photo {
        margin: 0 auto;
    }
}

@media (max-width: 768px) {
    .hero h1 {
        font-size: 1rem;
    }

    .hero-header {
        flex-direction: column;
        align-items: flex-start;
        gap: 1rem;
    }

    nav .container {
        flex-direction: column;
        align-items: flex-start;
        gap: 1rem;
    }

    nav ul {
        gap: 1rem;
        font-size: 0.85rem;
    }

    .social-links {
        order: -1;
    }

    .project-detail-header {
        flex-direction: column;
        align-items: flex-start;
        gap: 1rem;
    }
    
    .close-detail {
        align-self: flex-end;
    }
    
    .about-layout {
        gap: 20px;
    }
}
    
.subtab-nav { display:flex; gap:1rem; margin-bottom:2rem; border-bottom:2px solid #e1e5e9; padding-bottom:1rem; }
.subtab-btn { background:none; border:none; padding:0.8rem 1.5rem; font-size:1rem; color:#6b7280; cursor:pointer; border-bottom:3px solid transparent; font-weight:500; transition:all 0.3s; }
.subtab-btn:hover { color:#3b82f6; }
.subtab-btn.active { color:#1f2937; border-bottom-color:#3b82f6; }
.subtab-content { display:block; }


/* Nav background */
nav {
    background: var(--bg-nav);
    backdrop-filter: blur(8px);
    position: sticky;
    top: 0;
    z-index: 100;
    border-bottom: 1px solid var(--border-color);
}

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

body { background: var(--bg-main); }

/* Dark mode toggle button */
.theme-toggle {
    background: var(--toggle-bg);
    border: none;
    border-radius: 50px;
    width: 44px;
    height: 24px;
    cursor: pointer;
    position: relative;
    transition: background 0.3s;
    flex-shrink: 0;
}

.theme-toggle::after {
    content: '';
    position: absolute;
    top: 2px;
    left: 2px;
    width: 20px;
    height: 20px;
    background: white;
    border-radius: 50%;
    transition: transform 0.3s;
    box-shadow: 0 1px 4px rgba(0,0,0,0.2);
}

[data-theme="dark"] .theme-toggle::after {
    transform: translateX(20px);
}

.theme-toggle-wrap {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.theme-toggle-wrap span {
    font-size: 0.8rem;
    color: var(--text-muted);
    user-select: none;
}

/* Write-up / blog image utility class */
.writeup-img {
    max-width: 100%;
    height: auto;
    border-radius: 6px;
    margin: 0.75rem 0;
    display: block;
}

.writeup-img-half {
    max-width: 50%;
    height: auto;
    border-radius: 8px;
    margin: 0.75rem 0;
    display: block;
}

/* Project card thumbnail backgrounds */
.card-thm-thumb {
    background: linear-gradient(135deg, #0f2027 0%, #203a43 50%, #2c5364 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    flex-direction: column;
    gap: 0.5rem;
}

.card-thm-label {
    color: rgba(255, 255, 255, 0.5);
    font-size: 0.7rem;
    letter-spacing: 0.1em;
    text-transform: uppercase;
}

/* Theme toggle wrap positioning */
.theme-toggle-wrap-fixed {
    position: fixed;
    top: 1rem;
    right: 1.5rem;
    z-index: 9999;
}