:root {
    --white: #ffffff;
    --off-white: #f8f8f6;
    --light-gray: #efefed;
    --mid-gray: #c8c8c4;
    --text-dark: #1a1a1a;
    --text-mid: #444440;
    --text-light: #888884;
    --accent: #2a4a8a;
    --accent-light: #e8edf7;
    --border: #e0e0dc;
    --nav-height: 52px;
}

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

html {
    /* scroll-behavior: smooth; */
}

body {
    background: var(--white);
    color: var(--text-dark);
    font-family: 'Hiragino Kaku Gothic ProN', 'Hiragino Sans', 'Noto Sans JP', sans-serif;
    font-size: 15px;
    line-height: 1.75;
}

.u {
    text-decoration: underline;
    font-weight: bold; 
}

.b {
    font-weight: bold; 
}

/* ===================== NAV ===================== */
nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: var(--nav-height);
    background: rgba(255,255,255,0.97);
    border-bottom: 1px solid var(--border);
    display: flex;
    align-items: center;
    padding: 0 2rem;
    gap: 0.25rem;
    z-index: 1000;
    backdrop-filter: blur(6px);
}

.nav-item {
    position: relative;
}

.nav-link {
    display: flex;
    align-items: center;
    gap: 0.3rem;
    padding: 0.4rem 0.85rem;
    border-radius: 4px;
    color: var(--text-mid);
    text-decoration: none;
    font-size: 13.5px;
    font-weight: 500;
    letter-spacing: 0.02em;
    transition: background 0.15s, color 0.15s;
    cursor: pointer;
    white-space: nowrap;
    border: none;
    background: none;
    font-family: inherit;
}

.nav-link:hover, .nav-item.open > .nav-link {
    background: var(--accent-light);
    color: var(--accent);
}

.nav-link .arrow {
    font-size: 9px;
    transition: transform 0.2s;
    opacity: 0.6;
}

.nav-item.open > .nav-link .arrow {
    transform: rotate(180deg);
}

.dropdown {
    display: none;
    position: absolute;
    top: calc(100% + 2px);
    left: 0;
    background: var(--white);
    border: 1px solid var(--border);
    border-radius: 6px;
    box-shadow: 0 4px 20px rgba(0,0,0,0.08);
    min-width: 210px;
    overflow: hidden;
    /* ボタンとの隙間をパディングで埋めて消えにくくする */
    padding-top: 2px;
}

.nav-item.open .dropdown {
    display: block;
}

.dropdown a {
    display: block;
    padding: 0.55rem 1.1rem;
    font-size: 13px;
    color: var(--text-mid);
    text-decoration: none;
    transition: background 0.12s, color 0.12s;
    border-bottom: 1px solid var(--light-gray);
}

.dropdown a:last-child {
    border-bottom: none;
}

.dropdown a:hover {
    background: var(--accent-light);
    color: var(--accent);
}

/* ===================== MAIN ===================== */
main {
    padding-top: calc(var(--nav-height) + 3rem);
    max-width: 820px;
    margin: 0 auto;
    padding-left: 2rem;
    padding-right: 2rem;
    padding-bottom: 6rem;
}

/* ===================== HERO ===================== */
.hero {
    display: flex;
    gap: 2.5rem;
    align-items: flex-start;
    /* margin-bottom: 3.5rem; */
    padding-bottom: 2rem;
    /* border-bottom: 1px solid var(--border); */
}

.portrait-wrap {
    flex-shrink: 0;
}

.portrait {
    width: 130px;
    height: 160px;
    border-radius: 4px;
    background: var(--light-gray);
    object-fit: cover;
    display: block;
    border: 1px solid var(--border);
}

.portrait-placeholder {
    width: 130px;
    height: 160px;
    border-radius: 4px;
    background: var(--light-gray);
    border: 1px solid var(--border);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    color: var(--text-light);
    font-size: 12px;
}

.portrait-placeholder svg {
    opacity: 0.4;
}

.hero-info {
    flex: 1;
}

.affiliation {
    font-size: 13px;
    color: var(--text-mid); <!-- var(--text-light); -->
						    margin-bottom: 0.25rem;
    letter-spacing: 0.02em;
}

.name {
    font-size: 26px;
    font-weight: 600;
    color: var(--text-dark);
    letter-spacing: 0.04em;
    margin-bottom: 0.5rem;
    line-height: 1.3;
}

.email {
    font-size: 13.5px;
    color: var(--text-mid);
    margin-bottom: 1.25rem;
}

.email a {
    color: var(--accent);
    text-decoration: none;
}

.email a:hover {
    text-decoration: underline;
}

.ext-links {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-bottom: 1.5rem;
}

.ext-link {
    display: inline-flex;
    align-items: center;
    gap: 0.3rem;
    padding: 0.3rem 0.75rem;
    border: 1px solid var(--border);
    border-radius: 3px;
    font-size: 12.5px;
    color: var(--text-mid);
    text-decoration: none;
    background: var(--off-white);
    transition: border-color 0.15s, color 0.15s, background 0.15s;
    letter-spacing: 0.01em;
}

.ext-link:hover {
    border-color: var(--accent);
    color: var(--accent);
    background: var(--accent-light);
}

.bio {
    font-size: 14.5px;
    line-height: 1.8;
    color: var(--text-mid);
    margin-bottom: 0.75rem;
}

.keywords {
    font-size: 13px;
    color: var(--text-mid); <!-- var(--text-light); -->
}

.keywords strong {
    color: var(--text-mid);
}

/* ===================== SECTIONS ===================== */
section {
    margin-bottom: 4rem;
    scroll-margin-top: calc(var(--nav-height) + 1.5rem);
}

.section-group {
    margin-bottom: 3.5rem;
}

h2.group-title {
    font-size: 20px;
    font-weight: 600;
    color: var(--text-dark);
    letter-spacing: 0.04em;
    border-bottom: 2px solid var(--text-dark);
    padding-bottom: 0.5rem;
    margin-bottom: 1.25rem;
}

.sub-anchors {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem 1.25rem;
    margin-bottom: 2.5rem;
    font-size: 14px;
}

.sub-anchors a {
    color: var(--accent);
    text-decoration: none;
}

.sub-anchors a:hover {
    text-decoration: underline;
}

h3.sub-title {
    font-size: 15px;
    font-weight: 600;
    color: var(--text-dark);
    letter-spacing: 0.03em;
    border-left: 3px solid var(--accent);
    padding-left: 0.75rem;
    margin-top: 2.5rem;
    margin-bottom: 1rem;
    scroll-margin-top: calc(var(--nav-height) + 1.5rem);
}

h4.ssub-title {
    margin-top: 1.5rem;
}    

/* ===================== PUB LIST ===================== */
.pub-list {
    list-style: none;
    padding: 0;
    margin: 0;
}

.pub-list li {
    font-family: Optima, 'Palatino Linotype', Palatino, 'Book Antiqua', 'URW Palladio L', 'EB Garamond', Georgia, serif;
    font-size: 15px;
    line-height: 1.7;
    padding: 0.85rem 0;
    border-bottom: 1px solid var(--light-gray);
    <!-- color: var(--text-mid); -->
				 color: #1a1a1a; <!-- #2a2a28; -->
}

.pub-list li:last-child {
    <!-- border-bottom: 1px solid var(--light-gray);     -->
							 border-bottom: none;
}

.pub-list li::before {
    content: none;
}

/* ===================== HISTORY LIST ===================== */
.hist-list {
    list-style: none;
    padding: 0;
    margin: 0;
}

.hist-list li {
    font-size: 14px;
    line-height: 1.7;
    padding: 0.7rem 0;
    border-bottom: 1px solid var(--light-gray);
    color: var(--text-mid);
    <!-- display: flex; -->
			gap: 1.25rem;
}

.hist-list li:last-child {
    border-bottom: none;
    <!-- border-bottom: 1px solid var(--light-gray);     -->
}

.hist-year {
    flex-shrink: 0;
    width: 90px;
    color: var(--text-light);
    font-size: 13px;
    padding-top: 0.05rem;
}

/* ===================== RESPONSIVE ===================== */
@media (max-width: 600px) {
    .hero {
        flex-direction: column;
        align-items: center;
        text-align: center;
        gap: 1.5rem;
    }
    .ext-links {
        justify-content: center;
    }
    .sub-anchors {
        gap: 0.4rem 0.9rem;
    }
    nav {
        padding: 0 1rem;
        gap: 0;
    }
    .nav-link {
        padding: 0.4rem 0.55rem;
        font-size: 12.5px;
    }
}