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

:root {
    --primary: #272242;
    --cream: #dfcfba;
    --cream-light: #f1ebe3;
    --bg: #faf8f5;
    --text: #2f2e2e;
    --text-light: #6b6b6b;
    --border: #e0dcd7;
    --footer-bg: #2f2e2e;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: "Times New Roman", Times, Georgia, serif;
    color: var(--text);
    background: var(--bg);
    line-height: 1.75;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

a {
    color: var(--primary);
    text-decoration: none;
    transition: color 0.25s ease, opacity 0.25s ease;
}

a:hover {
    opacity: 0.7;
}

/* ===== Header ===== */
header {
    background: var(--primary);
    position: sticky;
    top: 0;
    z-index: 100;
}

.header-inner {
    max-width: 980px;
    margin: 0 auto;
    padding: 1.15rem 2.5rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    color: var(--cream) !important;
    font-size: 1.4rem;
    font-weight: normal;
    letter-spacing: 0.03em;
}

.logo:hover {
    opacity: 0.85 !important;
}

nav {
    display: flex;
    gap: 2.5rem;
}

nav a {
    color: rgba(241, 235, 227, 0.75);
    font-family: Helvetica, Arial, sans-serif;
    font-size: 0.88rem;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    padding-bottom: 4px;
    border-bottom: 2px solid transparent;
    transition: color 0.25s ease, border-color 0.25s ease;
}

nav a:hover {
    color: var(--cream-light);
    opacity: 1;
    border-bottom-color: rgba(223, 207, 186, 0.4);
}

nav a.active {
    color: var(--cream-light);
    border-bottom-color: var(--cream);
}

/* ===== Hero ===== */
.hero {
    position: relative;
    width: 100%;
    height: 520px;
    overflow: hidden;
}

.hero-img {
    position: absolute;
    inset: 0;
    width: 100%;
    height: 100%;
    object-fit: cover;
    object-position: center 40%;
}

.hero-overlay {
    position: absolute;
    inset: 0;
    background: linear-gradient(
        to bottom,
        rgba(39, 34, 62, 0.10) 0%,
        rgba(39, 34, 62, 0.40) 100%
    );
}

.hero-content {
    position: absolute;
    inset: 0;
    display: flex;
    align-items: flex-end;
    justify-content: center;
    padding-bottom: 3.5rem;
    z-index: 1;
}

.hero h1 {
    color: #fff;
    font-size: 3.6rem;
    font-weight: normal;
    letter-spacing: 0.06em;
    text-shadow: 0 2px 20px rgba(0, 0, 0, 0.35);
}

/* ===== About ===== */
.about {
    padding: 5rem 2.5rem 6rem;
}

.about-inner {
    max-width: 980px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: 320px 1fr;
    gap: 4rem;
    align-items: start;
}

.about-photo img {
    width: 100%;
    display: block;
    box-shadow: 0 8px 40px rgba(39, 34, 62, 0.18);
}

.about-text {
    padding-top: 0.5rem;
}

.about-text p {
    font-size: 1.15rem;
    margin-bottom: 1.25rem;
    color: var(--text);
    line-height: 1.85;
}

.about-text a {
    color: var(--primary);
    border-bottom: 1px solid rgba(39, 34, 62, 0.3);
    transition: border-color 0.25s ease;
}

.about-text a:hover {
    border-bottom-color: var(--primary);
    opacity: 1;
}

/* ===== Research Page ===== */
.research-page {
    flex: 1;
}

.research-layout {
    max-width: 980px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: 340px 1fr;
    gap: 4rem;
    padding: 4.5rem 2.5rem 6rem;
    align-items: start;
}

.sidebar-image {
    width: 100%;
    display: block;
    box-shadow: 0 8px 40px rgba(39, 34, 62, 0.15);
}

.research-content h1 {
    font-size: 3.2rem;
    font-weight: normal;
    color: var(--primary);
    margin-bottom: 3rem;
    letter-spacing: 0.03em;
}

.research-category {
    margin-bottom: 3rem;
}

.research-category h2 {
    font-size: 1.25rem;
    font-weight: normal;
    color: var(--primary);
    letter-spacing: 0.1em;
    text-transform: uppercase;
    margin-bottom: 1.5rem;
    padding-bottom: 0.6rem;
    border-bottom: 1px solid var(--border);
}

.paper {
    margin-bottom: 2.25rem;
}

.paper:last-child {
    margin-bottom: 0;
}

.paper h3 {
    font-size: 1.12rem;
    font-weight: bold;
    color: var(--text);
    margin-bottom: 0.25rem;
    line-height: 1.5;
}

.paper .authors {
    font-size: 0.95rem;
    color: var(--text-light);
    font-style: italic;
    margin-bottom: 0.15rem;
}

.paper .venue {
    font-size: 0.93rem;
    color: var(--text-light);
    margin-bottom: 0.5rem;
}

.paper-links {
    display: flex;
    flex-wrap: wrap;
    gap: 0.6rem;
    margin-top: 0.6rem;
}

.paper-links a {
    font-family: Helvetica, Arial, sans-serif;
    font-size: 0.8rem;
    color: var(--primary);
    padding: 0.32rem 0.9rem;
    border: 1px solid var(--primary);
    letter-spacing: 0.03em;
    transition: background 0.25s ease, color 0.25s ease;
}

.paper-links a:hover {
    background: var(--primary);
    color: var(--cream-light);
    opacity: 1;
}

/* ===== Footer ===== */
footer {
    margin-top: auto;
    background: var(--footer-bg);
    padding: 2rem 2.5rem;
    text-align: center;
}

footer p {
    color: var(--cream);
    font-family: Helvetica, Arial, sans-serif;
    font-size: 0.82rem;
    letter-spacing: 0.06em;
    opacity: 0.65;
}

/* ===== Responsive ===== */
@media (max-width: 820px) {
    .header-inner {
        flex-direction: column;
        gap: 0.75rem;
        padding: 1rem 1.5rem;
    }

    nav {
        gap: 1.75rem;
    }

    .hero {
        height: 360px;
    }

    .hero h1 {
        font-size: 2.5rem;
    }

    .about {
        padding: 3rem 1.5rem 4rem;
    }

    .about-inner {
        grid-template-columns: 1fr;
        gap: 2.5rem;
    }

    .about-photo {
        max-width: 280px;
    }

    .research-layout {
        grid-template-columns: 1fr;
        gap: 2.5rem;
        padding: 3rem 1.5rem 4rem;
    }

    .sidebar-image {
        max-width: 280px;
    }

    .research-content h1 {
        font-size: 2.5rem;
    }
}

@media (max-width: 480px) {
    .hero {
        height: 280px;
    }

    .hero h1 {
        font-size: 2rem;
        padding-bottom: 2rem;
    }

    nav a {
        font-size: 0.82rem;
        letter-spacing: 0.06em;
    }

    nav {
        gap: 1.25rem;
    }

    .about-text p {
        font-size: 1.05rem;
    }

    .about-photo {
        max-width: 240px;
    }

    .sidebar-image {
        max-width: 240px;
    }
}