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

:root {
    --color-bg: #fafaf8;
    --color-text: #2c2c2c;
    --color-text-secondary: #5a5a5a;
    --color-accent: #1a4a6e;
    --color-accent-hover: #0d3350;
    --color-border: #d8d5cf;
    --color-header-bg: #ffffff;
    --color-card-bg: #ffffff;
    --font-body: 'Source Serif 4', 'Georgia', serif;
    --font-heading: 'DM Sans', 'Helvetica Neue', sans-serif;
    --max-width: 900px;
}

@import url('https://fonts.googleapis.com/css2?family=Source+Serif+4:ital,opsz,wght@0,8..60,300;0,8..60,400;0,8..60,600;1,8..60,400&family=DM+Sans:wght@400;500;600&display=swap');

html { font-size: 17px; scroll-behavior: smooth; }
body {
    font-family: var(--font-body);
    color: var(--color-text);
    background: var(--color-bg);
    line-height: 1.7;
    -webkit-font-smoothing: antialiased;
}

a {
    color: var(--color-accent);
    text-decoration: none;
    border-bottom: 1px solid transparent;
    transition: border-color 0.2s;
}
a:hover { border-bottom-color: var(--color-accent); }

/* ── Header ── */
header {
    background: var(--color-header-bg);
    border-bottom: 1px solid var(--color-border);
    position: sticky;
    top: 0;
    z-index: 100;
}
.header-inner {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 1rem 1.5rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1.5rem;
}
.site-title {
    font-family: var(--font-heading);
    font-weight: 600;
    font-size: 1.15rem;
    color: var(--color-text);
    white-space: nowrap;
    border-bottom: none;
    letter-spacing: -0.01em;
}
.site-title:hover { color: var(--color-accent); border-bottom: none; }

nav .nav-links {
    list-style: none;
    display: flex;
    gap: 1.6rem;
    align-items: center;
}
nav .nav-links li a {
    font-family: var(--font-heading);
    font-size: 0.88rem;
    font-weight: 500;
    color: var(--color-text-secondary);
    letter-spacing: 0.01em;
    border-bottom: none;
    padding-bottom: 2px;
    transition: color 0.2s;
}
nav .nav-links li a:hover,
nav .nav-links li a.active {
    color: var(--color-accent);
}

.nav-toggle {
    display: none;
    background: none;
    border: none;
    font-size: 1.4rem;
    cursor: pointer;
    color: var(--color-text);
}

/* ── Main ── */
main {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 2.5rem 1.5rem 4rem;
}

/* ── About Page ── */
.about {
    display: flex;
    gap: 2.5rem;
    align-items: flex-start;
}
.about-sidebar {
    flex-shrink: 0;
    text-align: center;
}
.headshot {
    width: 180px;
    height: auto;
    border-radius: 4px;
    display: block;
    margin-bottom: 0.8rem;
}
.cv-link {
    font-family: var(--font-heading);
    font-size: 0.85rem;
    font-weight: 500;
    display: inline-block;
    padding: 0.35rem 1rem;
    border: 1px solid var(--color-accent);
    border-radius: 3px;
    color: var(--color-accent);
    transition: background 0.2s, color 0.2s;
}
.cv-link:hover {
    background: var(--color-accent);
    color: #fff;
    border-bottom-color: var(--color-accent);
}

.about-text h2 {
    font-family: var(--font-heading);
    font-size: 1.35rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--color-text);
}
.about-text p { margin-bottom: 0.9rem; }
.about-text p:last-child { margin-bottom: 0; }

/* ── Section Headings (Publications, etc.) ── */
.page-heading {
    font-family: var(--font-heading);
    font-size: 1.35rem;
    font-weight: 600;
    margin-bottom: 0.4rem;
    color: var(--color-text);
}

.section-heading {
    font-family: var(--font-heading);
    font-size: 1.05rem;
    font-weight: 600;
    color: var(--color-accent);
    margin-top: 2.2rem;
    margin-bottom: 1.2rem;
    padding-bottom: 0.35rem;
    border-bottom: 2px solid var(--color-border);
}

.section-intro {
    margin-bottom: 1.5rem;
    color: var(--color-text-secondary);
    font-size: 0.95rem;
}
.section-intro a { font-size: 0.95rem; }

/* ── Paper List ── */
.paper {
    margin-bottom: 1.6rem;
    padding-left: 0;
}
.paper-title {
    font-weight: 600;
    font-size: 0.97rem;
    line-height: 1.5;
}
.paper-title a { border-bottom: 1px solid var(--color-border); }
.paper-title a:hover { border-bottom-color: var(--color-accent); }
.paper-authors {
    font-size: 0.9rem;
    color: var(--color-text-secondary);
    margin-top: 0.15rem;
}
.paper-venue {
    font-size: 0.9rem;
    color: var(--color-text-secondary);
    font-style: italic;
    margin-top: 0.1rem;
}
.paper-extra {
    font-size: 0.85rem;
    color: var(--color-text-secondary);
    margin-top: 0.25rem;
    line-height: 1.6;
}
.paper-extra a {
    font-size: 0.85rem;
}

/* ── Data List ── */
.data-item {
    margin-bottom: 1.4rem;
}
.data-item .data-title {
    font-weight: 600;
    font-size: 0.97rem;
}
.data-item .data-title a {
    border-bottom: 1px solid var(--color-border);
}
.data-item .data-title a:hover {
    border-bottom-color: var(--color-accent);
}
.data-item .data-source {
    font-size: 0.88rem;
    color: var(--color-text-secondary);
    margin-top: 0.1rem;
}
.data-item .data-authors {
    font-size: 0.88rem;
    color: var(--color-text-secondary);
}

/* ── Projects in Progress ── */
.projects-list {
    list-style: disc;
    padding-left: 1.4rem;
    color: var(--color-text-secondary);
    font-size: 0.95rem;
    line-height: 1.8;
}

/* ── Footer ── */
footer {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 1.5rem;
    text-align: center;
    font-size: 0.8rem;
    color: var(--color-text-secondary);
    border-top: 1px solid var(--color-border);
    font-family: var(--font-heading);
}

/* ── Responsive ── */
@media (max-width: 700px) {
    .nav-toggle { display: block; }
    nav .nav-links {
        display: none;
        flex-direction: column;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: var(--color-header-bg);
        border-bottom: 1px solid var(--color-border);
        padding: 1rem 1.5rem;
        gap: 0.8rem;
    }
    nav .nav-links.open { display: flex; }
    .about {
        flex-direction: column;
        align-items: center;
        text-align: left;
    }
    .about-sidebar { text-align: center; }
    .headshot { width: 150px; }
    main { padding-top: 1.5rem; }
}