:root {
    --color-text: #222;
    --color-text-secondary: #555;
    --color-bg: #fff;
    --color-bg-alt: #f7f7f5;
    --color-border: #ddd;
    --color-link: #1a5276;
    --font-serif: 'Source Serif 4', Georgia, serif;
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    --max-width: 820px;
    --header-height: 56px;
}

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

html {
    scroll-behavior: smooth;
    scroll-padding-top: calc(var(--header-height) + 1.5rem);
}

body {
    font-family: var(--font-sans);
    font-size: 15px;
    line-height: 1.7;
    color: var(--color-text);
    background: var(--color-bg);
}

a {
    color: var(--color-link);
    text-decoration: none;
}
a:hover {
    text-decoration: underline;
}

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

ul { list-style: none; }

/* Layout */
.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 1.25rem;
}

/* Navbar */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: var(--header-height);
    background: rgba(255,255,255,0.95);
    backdrop-filter: blur(8px);
    border-bottom: 1px solid var(--color-border);
    z-index: 100;
    display: flex;
    align-items: center;
}

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

.logo {
    font-family: var(--font-serif);
    font-size: 1.15rem;
    font-weight: 600;
    color: var(--color-text);
    text-decoration: none;
}
.logo:hover { text-decoration: none; }

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

.nav-links a {
    font-size: 0.85rem;
    font-weight: 400;
    color: var(--color-text-secondary);
    letter-spacing: 0.01em;
}
.nav-links a:hover {
    color: var(--color-text);
    text-decoration: none;
}

.mobile-menu-btn {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    padding: 4px;
}
.mobile-menu-btn .bar {
    display: block;
    width: 20px;
    height: 2px;
    background: var(--color-text);
    margin: 4px 0;
    transition: 0.2s;
}

/* Header / About */
.header-section {
    padding-top: calc(var(--header-height) + 3rem);
    padding-bottom: 3rem;
}

.header-content {
    display: grid;
    grid-template-columns: 1fr 220px;
    gap: 2.5rem;
    align-items: start;
}

.site-name {
    font-family: var(--font-serif);
    font-size: 2rem;
    font-weight: 600;
    color: var(--color-text);
    margin-bottom: 0.25rem;
    line-height: 1.2;
}

.site-affiliation {
    font-size: 0.95rem;
    color: var(--color-text-secondary);
    margin-bottom: 0.15rem;
    line-height: 1.5;
}

.site-affiliation-secondary {
    font-size: 0.85rem;
    color: var(--color-text-secondary);
    margin-bottom: 1.25rem;
}

.header-bio {
    font-size: 0.93rem;
    line-height: 1.7;
    color: var(--color-text);
    margin-bottom: 0.75rem;
}

.header-links {
    margin-top: 1rem;
    font-size: 0.9rem;
}
.header-links a {
    color: var(--color-link);
}
.link-sep {
    margin: 0 0.5rem;
    color: var(--color-text-secondary);
}

.header-photo-wrapper {
    width: 220px;
}
.header-photo {
    width: 100%;
    border-radius: 4px;
}

/* Sections */
.section {
    padding: 2.5rem 0;
}

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

.section-title {
    font-family: var(--font-serif);
    font-size: 1.35rem;
    font-weight: 600;
    color: var(--color-text);
    margin-bottom: 1.5rem;
    padding-bottom: 0.5rem;
    border-bottom: 1px solid var(--color-border);
}

/* Research */
.research-areas {
    display: flex;
    flex-direction: column;
    gap: 1.25rem;
}

.research-area h3 {
    font-family: var(--font-serif);
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 0.25rem;
    color: var(--color-text);
}

.research-area p {
    font-size: 0.9rem;
    color: var(--color-text-secondary);
    line-height: 1.65;
}

/* Publications */
.publications-list {
    display: flex;
    flex-direction: column;
    gap: 1.1rem;
}

.pub-item {
    padding-bottom: 1.1rem;
    border-bottom: 1px solid #eee;
}
.pub-item:last-child {
    border-bottom: none;
    padding-bottom: 0;
}

.pub-title {
    font-family: var(--font-serif);
    font-size: 0.95rem;
    font-weight: 600;
    line-height: 1.45;
    color: var(--color-text);
    margin-bottom: 0.15rem;
}

.pub-meta {
    font-size: 0.87rem;
    color: var(--color-text-secondary);
    line-height: 1.5;
}

/* Teaching */
.teaching-list {
    display: flex;
    flex-direction: column;
    gap: 0.9rem;
}

.teaching-item {
    padding-bottom: 0.9rem;
    border-bottom: 1px solid #eee;
}
.teaching-item:last-child {
    border-bottom: none;
    padding-bottom: 0;
}

.teaching-role {
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--color-text);
}

.teaching-course {
    font-size: 0.87rem;
    color: var(--color-text-secondary);
}

/* Presentations */
.presentations-list {
    display: flex;
    flex-direction: column;
    gap: 1.1rem;
}

.pres-item {
    padding-bottom: 1.1rem;
    border-bottom: 1px solid #eee;
}
.pres-item:last-child {
    border-bottom: none;
    padding-bottom: 0;
}

.pres-title {
    font-family: var(--font-serif);
    font-size: 0.95rem;
    font-weight: 600;
    font-style: italic;
    line-height: 1.45;
    color: var(--color-text);
    margin-bottom: 0.1rem;
}

.pres-meta {
    font-size: 0.87rem;
    color: var(--color-text-secondary);
    line-height: 1.5;
}

/* Contact */
.contact-info {
    font-size: 0.93rem;
    line-height: 1.7;
    color: var(--color-text-secondary);
}
.contact-email {
    margin-top: 0.5rem;
}
.contact-email a {
    color: var(--color-link);
}

/* Footer */
footer {
    border-top: 1px solid var(--color-border);
    padding: 1.5rem 0;
    margin-top: 1rem;
}

.footer-content {
    text-align: center;
    font-size: 0.8rem;
    color: var(--color-text-secondary);
}

/* Responsive */
@media (max-width: 640px) {
    .header-content {
        grid-template-columns: 1fr;
    }

    .header-photo-wrapper {
        width: 160px;
        order: -1;
    }

    .nav-links {
        position: absolute;
        top: var(--header-height);
        left: 0;
        width: 100%;
        flex-direction: column;
        align-items: flex-start;
        background: var(--color-bg);
        border-bottom: 1px solid var(--color-border);
        padding: 1rem 1.25rem;
        gap: 0.75rem;
        transform: translateY(-120%);
        transition: transform 0.25s ease;
    }

    .nav-links.active {
        transform: translateY(0);
    }

    .mobile-menu-btn {
        display: block;
    }

    .site-name {
        font-size: 1.6rem;
    }
}