:root {
    --bg: #fbf8f2;
    --surface: #ffffff;
    --ink: #1a1a1a;
    --ink-soft: #4a4a4a;
    --ink-muted: #777267;
    --rule: #e7e0cf;
    --accent: #8c2a3a;
    --accent-soft: #f3e3e6;
    --serif: "Fraunces", "Iowan Old Style", Georgia, serif;
    --sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
    --mono: "JetBrains Mono", ui-monospace, SFMono-Regular, monospace;
}

* {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    margin: 0;
    background: var(--bg);
    color: var(--ink);
    font-family: var(--sans);
    font-size: 17px;
    line-height: 1.65;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

a {
    color: var(--accent);
    text-decoration: none;
    border-bottom: 1px solid transparent;
    transition: border-color 0.15s ease;
}

a:hover {
    border-bottom-color: var(--accent);
}

h1, h2, h3 {
    font-family: var(--serif);
    font-weight: 600;
    letter-spacing: -0.015em;
    color: var(--ink);
    line-height: 1.2;
}

/* ---------- Top nav ---------- */
.topnav {
    position: sticky;
    top: 0;
    z-index: 100;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.1rem 2.2rem;
    background: rgba(251, 248, 242, 0.85);
    backdrop-filter: saturate(180%) blur(14px);
    -webkit-backdrop-filter: saturate(180%) blur(14px);
    border-bottom: 1px solid var(--rule);
}

.topnav .brand {
    font-family: var(--serif);
    font-weight: 700;
    font-size: 1.25rem;
    color: var(--ink);
    border: none;
    letter-spacing: 0.02em;
}

.topnav .links {
    display: flex;
    gap: 1.8rem;
}

.topnav .links a {
    color: var(--ink-soft);
    font-size: 0.92rem;
    font-weight: 500;
    border: none;
    position: relative;
}

.topnav .links a:hover {
    color: var(--accent);
}

/* ---------- Sections ---------- */
main {
    max-width: 820px;
    margin: 0 auto;
    padding: 0 2rem 4rem;
}

section {
    padding: 4.5rem 0 2rem;
    border-bottom: 1px solid var(--rule);
}

section:last-of-type {
    border-bottom: none;
}

section h2 {
    font-size: 1.7rem;
    margin: 0 0 1.6rem;
    position: relative;
    padding-bottom: 0.5rem;
}

section h2::after {
    content: "";
    position: absolute;
    bottom: 0;
    left: 0;
    width: 36px;
    height: 2px;
    background: var(--accent);
}

.section-intro {
    color: var(--ink-muted);
    margin: -0.5rem 0 2rem;
    font-size: 0.98rem;
}

/* ---------- Hero ---------- */
.hero {
    display: grid;
    grid-template-columns: 1.4fr 1fr;
    gap: 3rem;
    align-items: center;
    padding: 5.5rem 0 4rem;
    border-bottom: 1px solid var(--rule);
}

.hero-text .eyebrow {
    font-family: var(--mono);
    text-transform: uppercase;
    font-size: 0.72rem;
    letter-spacing: 0.12em;
    color: var(--accent);
    margin: 0 0 1rem;
}

.hero-text h1 {
    font-size: clamp(2.6rem, 6vw, 3.6rem);
    margin: 0 0 1.2rem;
}

.hero-text .tagline {
    font-size: 1.12rem;
    color: var(--ink-soft);
    margin: 0 0 1.4rem;
    line-height: 1.6;
}

.hero-text .tagline strong {
    color: var(--ink);
    font-weight: 600;
}

.hero-text .meta {
    display: flex;
    align-items: center;
    gap: 0.7rem;
    font-size: 0.92rem;
    color: var(--ink-muted);
    margin: 0 0 1.6rem;
}

.hero-text .meta .dot {
    width: 3px;
    height: 3px;
    background: var(--ink-muted);
    border-radius: 50%;
}

.socials {
    display: flex;
    flex-wrap: wrap;
    gap: 0.6rem;
}

.btn {
    display: inline-block;
    padding: 0.5rem 1rem;
    background: var(--surface);
    color: var(--ink);
    border: 1px solid var(--rule);
    border-radius: 999px;
    font-size: 0.88rem;
    font-weight: 500;
    transition: all 0.15s ease;
}

.btn:hover {
    background: var(--accent);
    color: #fff;
    border-color: var(--accent);
}

.hero-photo img {
    width: 100%;
    max-width: 280px;
    aspect-ratio: 1 / 1;
    object-fit: cover;
    object-position: center 20%;
    border-radius: 50%;
    box-shadow: 0 18px 40px -18px rgba(0, 0, 0, 0.35);
    margin-left: auto;
    display: block;
}

/* ---------- About ---------- */
#about p {
    color: var(--ink-soft);
    margin: 0 0 1rem;
}

.skills {
    display: flex;
    flex-wrap: wrap;
    gap: 0.45rem;
    margin-top: 1.4rem;
}

.chip {
    display: inline-block;
    padding: 0.32rem 0.78rem;
    background: var(--surface);
    border: 1px solid var(--rule);
    border-radius: 6px;
    font-size: 0.82rem;
    font-family: var(--mono);
    color: var(--ink-soft);
}

/* ---------- Papers ---------- */
.paper {
    background: var(--surface);
    border: 1px solid var(--rule);
    border-radius: 10px;
    margin-bottom: 1rem;
    transition: border-color 0.18s ease, box-shadow 0.18s ease;
}

.paper:hover {
    border-color: #d4c8ad;
    box-shadow: 0 6px 22px -12px rgba(0, 0, 0, 0.12);
}

.paper details > summary {
    list-style: none;
    cursor: pointer;
    padding: 1.5rem 1.7rem;
}

.paper details > summary::-webkit-details-marker {
    display: none;
}

.paper .venue {
    display: inline-block;
    font-family: var(--mono);
    font-size: 0.72rem;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--accent);
    background: var(--accent-soft);
    padding: 0.2rem 0.55rem;
    border-radius: 4px;
    margin-bottom: 0.7rem;
}

.paper h3 {
    font-size: 1.18rem;
    margin: 0 0 0.5rem;
    line-height: 1.35;
}

.paper .authors {
    margin: 0 0 0.9rem;
    font-size: 0.93rem;
    color: var(--ink-muted);
}

.paper .authors strong {
    color: var(--ink);
    font-weight: 600;
}

.paper-links {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 0.7rem;
    font-size: 0.88rem;
}

.paper-links a {
    color: var(--ink-soft);
    border-bottom: 1px solid var(--rule);
    padding-bottom: 1px;
}

.paper-links a:hover {
    color: var(--accent);
    border-bottom-color: var(--accent);
}

.expand-hint {
    margin-left: auto;
    font-family: var(--mono);
    font-size: 0.76rem;
    color: var(--ink-muted);
    letter-spacing: 0.04em;
}

.paper details[open] .expand-hint {
    color: var(--accent);
}

.writeup {
    padding: 0 1.7rem 1.7rem;
    border-top: 1px dashed var(--rule);
    padding-top: 1.3rem;
    margin-top: 0.3rem;
    color: var(--ink-soft);
}

.writeup p {
    margin: 0 0 0.95rem;
}

.writeup p:last-child {
    margin-bottom: 0;
}

.writeup strong {
    color: var(--ink);
}

/* ---------- Patents ---------- */
.patent-list {
    list-style: none;
    padding: 0;
    margin: 0;
}

.patent-list li {
    display: flex;
    justify-content: space-between;
    align-items: baseline;
    gap: 1rem;
    padding: 0.85rem 0;
    border-bottom: 1px dashed var(--rule);
}

.patent-list li:last-child {
    border-bottom: none;
}

.patent-list a {
    color: var(--ink);
    border-bottom: 1px solid transparent;
    flex: 1;
}

.patent-list a:hover {
    border-bottom-color: var(--accent);
    color: var(--accent);
}

.patent-id {
    font-family: var(--mono);
    font-size: 0.76rem;
    color: var(--ink-muted);
    white-space: nowrap;
}

/* ---------- Timeline ---------- */
.timeline {
    list-style: none;
    padding: 0;
    margin: 0;
    position: relative;
}

.timeline > li {
    position: relative;
    padding: 0 0 2rem 1.5rem;
    border-left: 2px solid var(--rule);
}

.timeline > li:last-child {
    padding-bottom: 0;
}

.timeline > li::before {
    content: "";
    position: absolute;
    left: -7px;
    top: 6px;
    width: 12px;
    height: 12px;
    background: var(--accent);
    border-radius: 50%;
    border: 3px solid var(--bg);
}

.timeline h3 {
    font-size: 1.1rem;
    margin: 0 0 0.2rem;
}

.timeline h3 .company {
    color: var(--accent);
    font-weight: 500;
}

.timeline .when {
    font-family: var(--mono);
    font-size: 0.82rem;
    color: var(--ink-muted);
    margin: 0 0 0.7rem;
}

.timeline ul {
    padding-left: 1.2rem;
    margin: 0;
    color: var(--ink-soft);
}

.timeline ul li {
    margin-bottom: 0.35rem;
}

/* ---------- Contact ---------- */
.contact-list {
    list-style: none;
    padding: 0;
    margin: 1rem 0 0;
}

.contact-list li {
    display: grid;
    grid-template-columns: 100px 1fr;
    align-items: baseline;
    padding: 0.6rem 0;
    border-bottom: 1px dashed var(--rule);
}

.contact-list li:last-child {
    border-bottom: none;
}

.contact-list li span {
    font-family: var(--mono);
    font-size: 0.78rem;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--ink-muted);
}

/* ---------- Footer ---------- */
footer {
    text-align: center;
    padding: 2.5rem 1rem 2rem;
    color: var(--ink-muted);
    font-size: 0.85rem;
    border-top: 1px solid var(--rule);
}

footer p {
    margin: 0;
}

/* ---------- Responsive ---------- */
@media (max-width: 720px) {
    .topnav {
        padding: 0.9rem 1.2rem;
    }
    .topnav .links {
        gap: 1.1rem;
    }
    .topnav .links a {
        font-size: 0.85rem;
    }
    main {
        padding: 0 1.3rem 3rem;
    }
    .hero {
        grid-template-columns: 1fr;
        gap: 2rem;
        padding: 3rem 0;
        text-align: left;
    }
    .hero-photo {
        order: -1;
    }
    .hero-photo img {
        max-width: 180px;
        margin: 0;
    }
    section {
        padding: 3.5rem 0 1.5rem;
    }
    .paper details > summary {
        padding: 1.2rem 1.2rem;
    }
    .writeup {
        padding: 1.1rem 1.2rem 1.3rem;
    }
    .expand-hint {
        margin-left: 0;
    }
    .patent-list li {
        flex-direction: column;
        gap: 0.2rem;
        align-items: flex-start;
    }
    .contact-list li {
        grid-template-columns: 1fr;
        gap: 0.1rem;
    }
}