/* ===================================
   CSS Custom Properties & Reset
   =================================== */

:root {
    /* Colors */
    --color-primary: #0f172a;
    --color-secondary: #1e293b;
    --color-accent: #3b82f6;
    --color-text: #1e293b;
    --color-text-light: #64748b;
    --color-bg: #ffffff;
    --color-bg-alt: #f8fafc;
    --color-border: #e2e8f0;

    /* Typography */
    --font-family-sans: 'Raleway', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-family-serif: 'Lora', serif;
    --font-family: var(--font-family-sans);
    /* Fallback/Default if needed, but we will be specific */
    --font-size-base: 16px;
    --font-size-sm: 0.875rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.5rem;
    --font-size-3xl: 2rem;
    --font-size-4xl: 2.5rem;
    --font-size-5xl: 3rem;

    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --spacing-2xl: 4rem;
    --spacing-3xl: 6rem;

    /* Layout */
    --container-max-width: 1200px;
    --border-radius: 0.5rem;

    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-base: 250ms ease;
    --transition-slow: 350ms ease;
}

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

html {
    scroll-behavior: smooth;
    font-size: var(--font-size-base);
}

body {
    font-family: var(--font-family-serif);
    color: var(--color-text);
    background-color: var(--color-bg);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* ===================================
   Typography
   =================================== */

h1,
h2,
h3,
h4,
h5,
h6 {
    font-family: var(--font-family-sans);
    font-weight: 500;
    line-height: 1.2;
    margin-bottom: var(--spacing-sm);
}

h1 {
    font-size: var(--font-size-5xl);
}

h2 {
    font-size: var(--font-size-3xl);
}

h3 {
    font-size: var(--font-size-2xl);
}

h4 {
    font-size: var(--font-size-xl);
}

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

a {
    color: var(--color-accent);
    text-decoration: none;
    transition: opacity var(--transition-fast);
}

a:hover {
    opacity: 0.8;
}

/* ===================================
   Layout Components
   =================================== */

.container {
    max-width: var(--container-max-width);
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

.section {
    padding: var(--spacing-3xl) 0;
}

.section-alt {
    background-color: var(--color-bg-alt);
}

.section-title {
    text-align: center;
    margin-bottom: var(--spacing-xl);
    font-size: var(--font-size-3xl);
    color: var(--color-primary);
}

/* ===================================
   Navigation
   =================================== */

.nav {
    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(--color-border);
    z-index: 1000;
    transition: transform var(--transition-base);
}

.nav .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-top: var(--spacing-sm);
    padding-bottom: var(--spacing-sm);
}

.nav-logo {
    font-family: var(--font-family-sans);
    font-size: var(--font-size-xl);
    font-weight: 700;
    color: var(--color-primary);
    display: flex;
    align-items: center;
}

.nav-headshot {
    width: 36px;
    height: 36px;
    border-radius: 50%;
    object-fit: cover;
    transition: transform var(--transition-base), box-shadow var(--transition-base);
}

.nav-headshot:hover {
    transform: scale(1.05);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
}

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 4px;
    background: none;
    border: none;
    cursor: pointer;
    padding: var(--spacing-xs);
}

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

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

.nav-link {
    color: var(--color-text);
    font-family: var(--font-family-sans);
    font-weight: 400;
    font-size: var(--font-size-sm);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    transition: color var(--transition-fast);
}

.nav-link:hover {
    color: var(--color-accent);
    opacity: 1;
}

/* ===================================
   Hero Section
   =================================== */

.hero {
    padding: calc(var(--spacing-3xl) + 60px) 0 var(--spacing-3xl);
    text-align: center;
    min-height: 60vh;
    display: flex;
    align-items: center;
    justify-content: center;
}

.hero-header {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-sm);
}

.hero-text {
    text-align: left;
}

.hero-headshot {
    width: 180px;
    height: 180px;
    border-radius: 50%;
    object-fit: cover;
    box-shadow: 0 6px 20px rgba(0, 0, 0, 0.12);
}

.hero-title {
    font-size: var(--font-size-5xl);
    font-weight: 300;
    color: var(--color-primary);
    margin-bottom: 0;
}

.hero-subtitle {
    font-size: var(--font-size-xl);
    color: var(--color-text-light);
    margin-bottom: var(--spacing-md);
    font-weight: 400;
}

.hero-description {
    font-size: var(--font-size-sm);
    color: var(--color-text-light);
    max-width: 600px;
    margin: 0;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    font-family: var(--font-family-sans);
}

/* ===================================
   About Section
   =================================== */

.about-content {
    max-width: 800px;
    margin: 0 auto;
}

.about-text {
    font-size: var(--font-size-lg);
    line-height: 1.8;
    color: var(--color-text);
    margin-bottom: var(--spacing-md);
}

/* ===================================
   Background Section
   =================================== */

.background-timeline {
    max-width: 900px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: var(--spacing-lg);
}

.background-item {
    display: flex;
    align-items: flex-start;
    gap: var(--spacing-xl);
    padding: var(--spacing-lg);
    background-color: var(--color-bg);
    border-radius: var(--border-radius);
    border: 1px solid var(--color-border);
    transition: transform var(--transition-base), box-shadow var(--transition-base);
}

.background-item:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.06);
}

.background-logo {
    flex-shrink: 0;
    width: 100px;
    height: 100px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: var(--border-radius);
    padding: var(--spacing-sm);
}

.background-logo-img {
    max-width: 80px;
    max-height: 80px;
    width: auto;
    height: auto;
    object-fit: contain;
}

.kemvi-logo {
    object-fit: cover;
    object-position: left center;
    width: 100%;
    height: 100%;
}

.background-content {
    flex: 1;
}

.background-title {
    font-size: var(--font-size-xl);
    color: var(--color-primary);
    margin-bottom: var(--spacing-xs);
    font-weight: 500;
}

.background-period {
    font-size: var(--font-size-sm);
    color: var(--color-text-light);
    margin-bottom: var(--spacing-sm);
    font-weight: 500;
}

.background-description {
    font-size: var(--font-size-base);
    color: var(--color-text);
    line-height: 1.7;
    margin-bottom: 0;
}

/* ===================================
   Portfolio Section
   =================================== */

.portfolio-intro {
    text-align: center;
    font-size: var(--font-size-lg);
    color: var(--color-text-light);
    margin-bottom: var(--spacing-xl);
}

.company-logos {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    justify-items: center;
    align-items: center;
    gap: var(--spacing-xl);
    max-width: 900px;
    margin: 0 auto;
}

.company-logo-img {
    height: 32px;
    width: auto;
    opacity: 0.7;
    filter: grayscale(100%);
    display: block;
    margin: auto;
    transition: transform var(--transition-base), filter var(--transition-base), opacity var(--transition-base);
    cursor: pointer;
}

.company-logo-img:hover {
    transform: scale(1.1);
    opacity: 1;
    filter: grayscale(0%) drop-shadow(0 0 8px rgba(59, 130, 246, 0.5));
}

/* Individual logo sizing to normalize visual appearance */
.logo-spacex {
    height: 32px;
}

.logo-anthropic {
    height: 24px;
    /* Narrower aspect ratio, reduce height */
}

.logo-openai {
    height: 42px;
    /* Wider aspect ratio, increase height */
}

.logo-xai {
    height: 48px;
}

.logo-pareto {
    height: 64px;
}

.logo-glean {
    height: 48px;
}

.logo-mearas {
    height: 64px;
}

.logo-crusoe {
    height: 48px;
    mix-blend-mode: multiply;
}

.portfolio-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-lg);
    max-width: 900px;
    margin: 0 auto;
}

.portfolio-card {
    background-color: var(--color-bg);
    padding: var(--spacing-xl);
    border-radius: var(--border-radius);
    border: 1px solid var(--color-border);
    transition: transform var(--transition-base), box-shadow var(--transition-base);
}

.portfolio-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 12px 24px rgba(0, 0, 0, 0.08);
}

.portfolio-title {
    font-size: var(--font-size-2xl);
    color: var(--color-primary);
    margin-bottom: var(--spacing-sm);
}

.portfolio-description {
    color: var(--color-text-light);
    line-height: 1.7;
}

/* ===================================
   Publications Section
   =================================== */

.sort-controls {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-xl);
}

.sort-label {
    font-size: var(--font-size-sm);
    color: var(--color-text-light);
    font-weight: 500;
}

.sort-btn {
    padding: var(--spacing-xs) var(--spacing-md);
    font-family: var(--font-family-sans);
    font-size: var(--font-size-sm);
    font-weight: 400;
    color: var(--color-text-light);
    background-color: transparent;
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.sort-btn:hover {
    color: var(--color-accent);
    border-color: var(--color-accent);
}

.sort-btn.active {
    color: white;
    background-color: var(--color-accent);
    border-color: var(--color-accent);
}

.publications-list {
    max-width: 900px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xl);
}

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

.publication:last-child {
    border-bottom: none;
}

.publication-title {
    font-size: var(--font-size-xl);
    margin-bottom: var(--spacing-xs);
}

.publication-title a {
    color: var(--color-primary);
    transition: color var(--transition-fast);
}

.publication-title a:hover {
    color: var(--color-accent);
    opacity: 1;
}

.publication-meta {
    font-size: var(--font-size-sm);
    color: var(--color-text-light);
    margin-bottom: var(--spacing-sm);
    font-style: italic;
}

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

/* Publication with image layout */
.publication-content {
    display: flex;
    gap: var(--spacing-lg);
    align-items: flex-start;
}

.publication-image {
    flex-shrink: 0;
    width: 200px;
    height: auto;
    border-radius: var(--border-radius);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    object-fit: cover;
}

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

/* Alternating layout: even items have image on right */
.publication:nth-child(even) .publication-content {
    flex-direction: row-reverse;
}

/* Responsive: stack vertically on mobile */
@media (max-width: 768px) {
    .publication-content {
        flex-direction: column;
    }

    .publication:nth-child(even) .publication-content {
        flex-direction: column;
    }

    .publication-image {
        width: 100%;
        max-width: 300px;
        margin: 0 auto var(--spacing-md);
    }
}

/* ===================================
   Projects Section
   =================================== */

.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: var(--spacing-lg);
}

.project-card {
    background-color: var(--color-bg);
    padding: var(--spacing-xl);
    border-radius: var(--border-radius);
    border: 1px solid var(--color-border);
    transition: transform var(--transition-base), box-shadow var(--transition-base);
}

.project-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 12px 24px rgba(0, 0, 0, 0.08);
}

.project-title {
    font-size: var(--font-size-xl);
    color: var(--color-primary);
    margin-bottom: var(--spacing-sm);
}

.project-description {
    color: var(--color-text-light);
    line-height: 1.7;
    margin-bottom: var(--spacing-md);
}

.project-link {
    display: inline-block;
    color: var(--color-accent);
    font-weight: 500;
    font-size: var(--font-size-sm);
}

.view-all-link {
    text-align: center;
    margin-top: var(--spacing-xl);
}

.view-all-link a {
    color: var(--color-accent);
    font-weight: 500;
    font-size: var(--font-size-lg);
    transition: opacity var(--transition-fast);
}

.view-all-link a:hover {
    opacity: 0.7;
}

/* ===================================
   Footer
   =================================== */

.footer {
    font-family: var(--font-family-sans);
    background-color: var(--color-primary);
    color: white;
    padding: var(--spacing-xl) 0;
    margin-top: var(--spacing-3xl);
}

.footer .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.footer-text {
    color: rgba(255, 255, 255, 0.8);
    font-size: var(--font-size-sm);
}

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

.footer-link {
    color: rgba(255, 255, 255, 0.8);
    font-size: var(--font-size-sm);
    transition: color var(--transition-fast);
}

.footer-link:hover {
    color: white;
    opacity: 1;
}

/* ===================================
   Animations
   =================================== */

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

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.fade-in {
    animation: fadeIn 0.8s ease forwards;
}

.fade-in-delay {
    opacity: 0;
    animation: fadeIn 0.8s ease 0.2s forwards;
}

.fade-in-delay-2 {
    opacity: 0;
    animation: fadeIn 0.8s ease 0.4s forwards;
}

/* ===================================
   Responsive Design
   =================================== */

@media (max-width: 768px) {
    :root {
        --font-size-5xl: 2.25rem;
        --font-size-3xl: 1.75rem;
        --spacing-3xl: 3rem;
    }

    .nav-toggle {
        display: flex;
    }

    .nav-menu {
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background-color: white;
        flex-direction: column;
        gap: 0;
        padding: var(--spacing-md);
        border-bottom: 1px solid var(--color-border);
        transform: translateY(-100%);
        opacity: 0;
        visibility: hidden;
        transition: transform var(--transition-base), opacity var(--transition-base);
    }

    .nav-menu.active {
        transform: translateY(0);
        opacity: 1;
        visibility: visible;
    }

    .nav-link {
        padding: var(--spacing-sm) 0;
        display: block;
    }

    .hero {
        min-height: 50vh;
        padding-top: calc(var(--spacing-2xl) + 60px);
    }

    .hero-header {
        flex-direction: column;
        gap: var(--spacing-sm);
    }

    .portfolio-grid,
    .projects-grid {
        grid-template-columns: 1fr;
    }

    .company-logos {
        gap: var(--spacing-lg);
    }

    .company-logo-img {
        height: 24px;
    }

    .background-item {
        flex-direction: column;
        gap: var(--spacing-md);
        align-items: center;
        text-align: center;
    }

    .background-logo {
        width: 80px;
        height: 80px;
    }

    .background-logo-img {
        max-width: 60px;
        max-height: 60px;
    }

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

@media (max-width: 480px) {
    :root {
        --font-size-5xl: 2rem;
        --font-size-3xl: 1.5rem;
        --spacing-xl: 2rem;
        --spacing-2xl: 2.5rem;
    }

    .container {
        padding: 0 var(--spacing-sm);
    }
}

/* ===================================
   Utility Classes
   =================================== */

.text-center {
    text-align: center;
}

.mt-sm {
    margin-top: var(--spacing-sm);
}

.mt-md {
    margin-top: var(--spacing-md);
}

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

.mt-xl {
    margin-top: var(--spacing-xl);
}

.mb-sm {
    margin-bottom: var(--spacing-sm);
}

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

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

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