:root {
    --primary-color: #2563eb;
    --primary-dark: #1e40af;
    --secondary-color: #64748b;
    --text-primary: #0f172a;
    --text-secondary: #475569;
    --bg-primary: #ffffff;
    --bg-secondary: #f8fafc;
    --bg-tertiary: #f1f5f9;
    --border-color: #e2e8f0;
    --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);
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--bg-primary);
    overflow-x: hidden;
}

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

/* Navigation */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background-color: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-color);
    z-index: 1000;
    transition: var(--transition);
}

.nav-container {
    max-width: 800px;
    margin: 0 auto;
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav-logo {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-primary);
    text-decoration: none;
    letter-spacing: -0.02em;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 2rem;
}

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

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

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background-color: var(--primary-color);
    transition: var(--transition);
}

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

.nav-toggle {
    display: none;
    flex-direction: column;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
    gap: 4px;
}

.nav-toggle span {
    width: 24px;
    height: 2px;
    background-color: var(--text-primary);
    transition: var(--transition);
}

/* Feed Layout - Single Column Twitter-like */
.feed-main {
    padding-top: 80px;
}

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

.feed-header {
    padding: 3rem 0 2rem;
    background: linear-gradient(to bottom, var(--bg-secondary), var(--bg-primary));
    border-bottom: 1px solid var(--border-color);
}

.feed-title {
    font-size: clamp(2rem, 5vw, 2.5rem);
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
    letter-spacing: -0.03em;
}

.feed-subtitle {
    font-size: 1rem;
    color: var(--text-secondary);
    font-weight: 400;
}

.posts-column {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
    padding: 2rem 0;
}

/* Post Cards */
.post-card {
    background-color: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: 1rem;
    padding: 2rem;
    transition: var(--transition);
    display: flex;
    flex-direction: column;
}

.post-card:hover {
    box-shadow: var(--shadow-md);
    border-color: var(--border-color);
}

.post-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.post-category {
    display: inline-block;
    padding: 0.25rem 0.75rem;
    background-color: var(--bg-secondary);
    color: var(--primary-color);
    border-radius: 0.375rem;
    font-size: 0.875rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.post-date {
    font-size: 0.875rem;
    color: var(--text-secondary);
}

.post-content {
    display: flex;
    flex-direction: column;
    gap: 1.25rem;
}

.post-title {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-primary);
    line-height: 1.3;
    letter-spacing: -0.01em;
    margin: 0;
}

.post-text {
    color: var(--text-secondary);
    line-height: 1.7;
    font-size: 1rem;
    margin: 0;
}

/* Link Cards */
.link-card {
    display: block;
    border: 1px solid var(--border-color);
    border-radius: 0.75rem;
    padding: 1rem;
    text-decoration: none;
    transition: var(--transition);
    background-color: var(--bg-secondary);
}

.link-card:hover {
    border-color: var(--primary-color);
    box-shadow: var(--shadow-sm);
    transform: translateY(-1px);
}

.link-card-content {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.link-card-icon {
    font-size: 1.5rem;
    flex-shrink: 0;
}

.link-card-text {
    flex: 1;
    min-width: 0;
}

.link-card-title {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.25rem;
}

.link-card-domain {
    font-size: 0.875rem;
    color: var(--text-secondary);
}

/* Video Embed */
.video-embed {
    position: relative;
    width: 100%;
    padding-bottom: 56.25%; /* 16:9 aspect ratio */
    height: 0;
    overflow: hidden;
    border-radius: 0.75rem;
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
}

.video-embed iframe {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    border: none;
}

/* About Page */
.about-hero {
    padding: 6rem 0 3rem;
    background: linear-gradient(to bottom, var(--bg-secondary), var(--bg-primary));
    border-bottom: 1px solid var(--border-color);
}

.about-hero-title {
    font-size: clamp(2.5rem, 6vw, 4rem);
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
    letter-spacing: -0.03em;
}

.about-hero-subtitle {
    font-size: 1.25rem;
    color: var(--text-secondary);
    font-weight: 400;
}

.about-content-section {
    padding: 4rem 0;
}

.about-grid {
    display: grid;
    grid-template-columns: 1fr 300px;
    gap: 3rem;
}

.about-main h2 {
    font-size: 2rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-top: 3rem;
    margin-bottom: 1.5rem;
    letter-spacing: -0.02em;
}

.about-main h2:first-child {
    margin-top: 0;
}

.about-main p {
    font-size: 1.125rem;
    line-height: 1.8;
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
}

.about-sidebar {
    position: sticky;
    top: 100px;
    height: fit-content;
}

.sidebar-card {
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 0.75rem;
    padding: 2rem;
}

.sidebar-card h3 {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 1rem;
}

.sidebar-card p {
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
    line-height: 1.7;
}

.sidebar-links {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.sidebar-link {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    color: var(--text-primary);
    text-decoration: none;
    padding: 0.75rem;
    border-radius: 0.5rem;
    transition: var(--transition);
}

.sidebar-link:hover {
    background-color: var(--bg-primary);
    color: var(--primary-color);
}

.sidebar-link span {
    font-size: 1.25rem;
}

/* Experience Timeline */
.experience-timeline {
    max-width: 800px;
    margin: 2rem 0;
    position: relative;
    padding-left: 2rem;
}

.experience-timeline::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 2px;
    background: linear-gradient(to bottom, var(--primary-color), var(--border-color));
}

.timeline-item {
    position: relative;
    margin-bottom: 3rem;
    padding-left: 2rem;
}

.timeline-item:last-child {
    margin-bottom: 0;
}

.timeline-marker {
    position: absolute;
    left: -1.5rem;
    top: 0.5rem;
    width: 12px;
    height: 12px;
    border-radius: 50%;
    background-color: var(--primary-color);
    border: 3px solid var(--bg-primary);
    box-shadow: var(--shadow-md);
}

.timeline-content {
    background-color: var(--bg-secondary);
    padding: 2rem;
    border-radius: 0.75rem;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
    border: 1px solid var(--border-color);
}

.timeline-content:hover {
    box-shadow: var(--shadow-md);
    transform: translateX(4px);
}

.timeline-title {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

.timeline-company {
    font-size: 1.125rem;
    color: var(--primary-color);
    font-weight: 600;
    margin-bottom: 0.25rem;
}

.timeline-period {
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin-bottom: 1rem;
}

.timeline-description {
    color: var(--text-secondary);
    line-height: 1.7;
}

/* Competencies Grid */
.competencies-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
    margin: 2rem 0;
}

.competency-card {
    background-color: var(--bg-secondary);
    padding: 2rem;
    border-radius: 0.75rem;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
    border: 1px solid var(--border-color);
}

.competency-card:hover {
    box-shadow: var(--shadow-md);
    transform: translateY(-4px);
    border-color: var(--primary-color);
}

.competency-title {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 1rem;
    letter-spacing: -0.01em;
}

.competency-description {
    color: var(--text-secondary);
    line-height: 1.7;
    font-size: 1rem;
}

/* Footer */
.footer {
    background-color: var(--bg-tertiary);
    padding: 2rem 0;
    text-align: center;
    color: var(--text-secondary);
    font-size: 0.875rem;
    border-top: 1px solid var(--border-color);
    margin-top: 3rem;
}

.footer-links {
    display: flex;
    justify-content: center;
    gap: 1.5rem;
    margin-top: 1rem;
    flex-wrap: wrap;
}

.footer-links a {
    color: var(--text-secondary);
    text-decoration: none;
    transition: var(--transition);
}

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

/* Responsive Design */
@media (max-width: 768px) {
    .nav-container {
        max-width: 100%;
        padding: 1rem 1.5rem;
    }

    .nav-menu {
        position: fixed;
        left: -100%;
        top: 70px;
        flex-direction: column;
        background-color: var(--bg-primary);
        width: 100%;
        text-align: center;
        transition: var(--transition);
        box-shadow: var(--shadow-lg);
        padding: 2rem 0;
        gap: 0;
    }

    .nav-menu.active {
        left: 0;
    }

    .nav-menu li {
        padding: 1rem 0;
    }

    .nav-toggle {
        display: flex;
    }

    .nav-toggle.active span:nth-child(1) {
        transform: rotate(45deg) translate(5px, 5px);
    }

    .nav-toggle.active span:nth-child(2) {
        opacity: 0;
    }

    .nav-toggle.active span:nth-child(3) {
        transform: rotate(-45deg) translate(7px, -6px);
    }

    .feed-container {
        padding: 0 1.5rem;
    }

    .feed-header {
        padding: 2rem 0 1.5rem;
    }

    .posts-column {
        gap: 1.25rem;
        padding: 1.5rem 0;
    }

    .post-card {
        padding: 1.5rem;
        border-radius: 0.75rem;
    }

    .post-title {
        font-size: 1.25rem;
    }

    .post-text {
        font-size: 0.9375rem;
    }

    .link-card {
        padding: 0.875rem;
    }

    .link-card-icon {
        font-size: 1.25rem;
    }

    .link-card-title {
        font-size: 0.9375rem;
    }

    .about-grid {
        grid-template-columns: 1fr;
        gap: 2rem;
    }

    .about-sidebar {
        position: static;
    }

    .experience-timeline {
        padding-left: 1.5rem;
    }

    .timeline-item {
        padding-left: 1.5rem;
    }

    .timeline-marker {
        left: -1.25rem;
    }

    .competencies-grid {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }

    .footer-links {
        flex-direction: column;
        gap: 0.75rem;
    }
}

@media (max-width: 480px) {
    .feed-container {
        padding: 0 1rem;
    }

    .feed-header {
        padding: 1.5rem 0 1rem;
    }

    .posts-column {
        padding: 1rem 0;
    }

    .post-card {
        padding: 1.25rem;
    }

    .post-title {
        font-size: 1.125rem;
    }

    .post-text {
        font-size: 0.875rem;
    }

    .link-card-content {
        gap: 0.75rem;
    }

    .link-card-icon {
        font-size: 1.125rem;
    }

    .about-hero {
        padding: 4rem 0 2rem;
    }

    .about-content-section {
        padding: 2rem 0;
    }

    .about-main h2 {
        font-size: 1.5rem;
        margin-top: 2rem;
    }

    .about-main p {
        font-size: 1rem;
    }
}

/* Smooth scroll offset for fixed navbar */
section {
    scroll-margin-top: 80px;
}