/* Original junwooweb.github.io homepage styles. */
:root {
    --text-main: #1e293b;
    --text-light: #64748b;
    --accent: #2563eb;
    --accent-light: #eff6ff;
    --bg-tag: #f1f5f9;
    --border-color: #e2e8f0;
    --postech-color: #C9006C;
    --card-bg: #fafbfd;
}

* { box-sizing: border-box; }
body { font-family: 'Inter', sans-serif; line-height: 1.65; margin: 0; color: var(--text-main); background: #fff; }
a { text-decoration: none; color: inherit; transition: color 0.2s; }

/* ── 네비게이션 ── */
nav { background: rgba(255,255,255,0.92); backdrop-filter: blur(8px); border-bottom: 1px solid var(--border-color); position: sticky; top: 0; z-index: 100; }
.nav-inner { max-width: 1000px; margin: 0 auto; padding: 0.9rem 1.5rem; display: flex; justify-content: space-between; align-items: center; }
.nav-logo { font-weight: 800; font-size: 1.15rem; letter-spacing: -0.5px; color: var(--text-main); }
.nav-logo:hover { color: var(--accent); }
.nav-menu a { margin-left: 2rem; font-size: 0.9rem; color: var(--text-light); font-weight: 600; }
.nav-menu a:hover, .nav-menu a.active { color: var(--accent); }

/* ── 컨테이너 ── */
.container { max-width: 1500px; margin: 3.5rem auto; padding: 0 1.5rem; }
.two-col { display: flex; gap: 5rem; align-items: flex-start; }
.col-left { flex: 1; min-width: 0; order: -1; }
.col-right { flex: 1; min-width: 0; }
.col-right::-webkit-scrollbar { width: 4px; }
.col-right::-webkit-scrollbar-thumb { background: #cbd5e1; border-radius: 4px; }

/* ── 섹션 타이틀 ── */
.section-title {
    font-size: 1.55rem;
    font-weight: 800;
    color: var(--text-main);
    margin-bottom: 1.5rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding-bottom: 0.65rem;
    border-bottom: 2.5px solid var(--border-color);
    letter-spacing: -0.5px;
}
.section-title .material-symbols-outlined { font-size: 1.4rem; color: var(--accent); }

/* ── 1. 프로필 ── */
.profile-section { display: flex; gap: 3rem; margin-bottom: 4rem; align-items: flex-start; }
.profile-img {
    width: 190px; height: 190px;
    border-radius: 50%;
    object-fit: cover;
    border: 3px solid #fff;
    box-shadow: 0 4px 24px rgba(37,99,235,0.12), 0 1px 4px rgba(0,0,0,0.08);
    flex-shrink: 0;
}
.profile-info h1 {
    margin: 0 0 0.45rem 0;
    font-size: 2.9rem;
    font-weight: 800;
    letter-spacing: -2px;
    color: var(--text-main);
}
.profile-role { font-size: 1rem; color: var(--text-light); margin-bottom: 1rem; line-height: 1.75; }
.profile-bio { margin-bottom: 1.4rem; color: #374151; line-height: 1.8; font-size: 0.97rem; }

/* 키워드 태그 */
.keyword-box { display: flex; gap: 0.4rem; flex-wrap: wrap; margin-bottom: 1.5rem; }
.tag {
    background: var(--bg-tag); color: #475569;
    padding: 3px 11px; border-radius: 20px;
    font-size: 0.8rem; font-weight: 600; border: 1px solid var(--border-color);
}

/* 버튼 그룹 */
.btn-group { display: flex; gap: 0.75rem; flex-wrap: wrap; }
.btn {
    display: inline-flex; align-items: center; gap: 0.4rem;
    padding: 8px 16px; border: 1.5px solid var(--border-color); border-radius: 8px;
    font-size: 0.88rem; font-weight: 600; color: var(--text-main);
    transition: all 0.18s; cursor: pointer;
}
.btn:hover { background: var(--text-main); color: #fff; border-color: var(--text-main); transform: translateY(-1px); box-shadow: 0 4px 12px rgba(0,0,0,0.1); }
/* 주요 버튼 (Email) — 색상 채움으로 강조 */
.btn-primary {
    background: var(--accent); color: #fff;
    border-color: var(--accent);
}
.btn-primary:hover { background: #1d4ed8; border-color: #1d4ed8; color: #fff; }
.material-symbols-outlined { font-size: 1.1rem; }

/* ── 2. Doctoral Research ── */
.doctoral-section { margin-bottom: 4rem; }
.doctoral-card {
    position: relative;
    background: linear-gradient(135deg, #eff6ff 0%, #f8faff 55%, #f0fdf4 100%);
    border: 1px solid #bfdbfe;
    border-left: 5px solid var(--accent);
    border-radius: 14px;
    padding: 2rem 2.4rem;
    overflow: hidden;
}
.doctoral-card::after {
    content: '';
    position: absolute;
    top: -50px; right: -50px;
    width: 200px; height: 200px;
    background: radial-gradient(circle, rgba(37,99,235,0.06) 0%, transparent 70%);
    border-radius: 50%;
    pointer-events: none;
}
.doctoral-topic {
    font-size: 1.3rem;
    font-weight: 800;
    color: var(--accent);
    margin: 0 0 0.75rem 0;
    letter-spacing: -0.4px;
    display: flex;
    align-items: center;
    gap: 0.55rem;
}
.doctoral-topic .material-symbols-outlined { font-size: 1.4rem; }
.doctoral-desc {
    font-size: 0.97rem;
    color: #374151;
    line-height: 1.85;
    margin: 0;
}

/* ── 3. Research Areas ── */
.areas-section { margin-bottom: 4rem; }
.areas-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1.2rem; }
.area-card {
    background: var(--card-bg); padding: 1.4rem 1.5rem;
    border-radius: 12px; border: 1px solid var(--border-color);
    transition: transform 0.2s, box-shadow 0.2s, border-color 0.2s;
}
.area-card:hover { transform: translateY(-3px); border-color: var(--accent); box-shadow: 0 6px 20px rgba(37,99,235,0.08); }
.area-card h3 { margin: 0 0 0.6rem 0; font-size: 1.02rem; font-weight: 700; display: flex; align-items: center; gap: 0.4rem; }
.area-card p { margin: 0; font-size: 0.89rem; color: var(--text-light); line-height: 1.6; }

/* ── AI Skills ── */
.skills-section { margin-bottom: 4rem; }
.skills-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1rem; }
.skill-card {
    text-align: center; padding: 1.5rem 1rem; border-radius: 12px;
    border: 1px solid var(--border-color); background: var(--card-bg);
    transition: transform 0.2s, box-shadow 0.2s, border-color 0.2s;
}
.skill-card:hover { transform: translateY(-3px); border-color: var(--accent); box-shadow: 0 6px 20px rgba(37,99,235,0.08); }
.skill-icon { font-size: 2rem; margin-bottom: 0.6rem; display: block; }
.skill-card h4 { margin: 0 0 0.4rem 0; font-size: 0.92rem; font-weight: 700; color: var(--text-main); }
.skill-card p { margin: 0; font-size: 0.78rem; color: var(--text-light); line-height: 1.4; }

/* ── 4. Current Research ── */
.research-section { margin-bottom: 4rem; }
.research-list { display: flex; flex-direction: column; gap: 1rem; }
.research-item {
    display: flex;
    align-items: flex-start;
    gap: 1.4rem;
    padding: 1.3rem 1.6rem;
    border: 1px solid var(--border-color);
    border-radius: 12px;
    background: var(--card-bg);
    transition: transform 0.2s, box-shadow 0.2s, border-color 0.2s;
}
.research-item:hover {
    transform: translateX(5px);
    box-shadow: 0 4px 20px rgba(37,99,235,0.07);
    border-color: #93c5fd;
}
.research-num {
    font-size: 1.9rem;
    font-weight: 800;
    color: #dbeafe;
    letter-spacing: -2px;
    line-height: 1;
    min-width: 2.8rem;
    text-align: center;
    padding-top: 3px;
    user-select: none;
    transition: color 0.2s;
}
.research-item:hover .research-num { color: #bfdbfe; }
.research-body { flex: 1; }
.research-title { font-size: 1.03rem; font-weight: 700; color: var(--text-main); margin-bottom: 0.45rem; line-height: 1.45; display: flex; align-items: center; gap: 0.5rem; flex-wrap: wrap; }
.research-main-badge {
    display: inline-block; background: var(--accent); color: #fff;
    font-size: 0.68rem; font-weight: 700; padding: 1px 8px; border-radius: 4px;
    letter-spacing: 0.04em; text-transform: uppercase; flex-shrink: 0;
}
.research-keywords { display: flex; gap: 0.35rem; flex-wrap: wrap; }
.research-kw {
    background: #eff6ff; color: #3b82f6;
    padding: 2px 10px; border-radius: 20px;
    font-size: 0.73rem; font-weight: 600;
    border: 1px solid #bfdbfe;
}

/* ── 5. Publications ── */
.pub-section { margin-bottom: 4rem; }
.pub-category {
    font-size: 1rem;
    font-weight: 700;
    color: var(--text-main);
    text-transform: uppercase;
    letter-spacing: 0.08em;
    margin: 2rem 0 0.8rem 0;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}
.pub-category::after {
    content: '';
    flex: 1;
    height: 1px;
    background: var(--border-color);
}
.pub-item {
    margin-bottom: 1rem;
    padding: 1.1rem 1.2rem;
    border-radius: 12px;
    border: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    gap: 1.5rem;
    transition: border-color 0.2s, box-shadow 0.2s;
    background: #fff;
}
.pub-item:hover {
    border-color: #93c5fd;
    box-shadow: 0 3px 16px rgba(37,99,235,0.07);
}
.pub-main { flex: 1; min-width: 0; }
.pub-badge {
    display: inline-block;
    background: var(--accent);
    color: white;
    padding: 1px 7px;
    border-radius: 4px;
    font-size: 0.7rem;
    font-weight: 700;
    margin-right: 0.45rem;
    vertical-align: middle;
    letter-spacing: 0.04em;
}
.pub-badge.conf { background: #d97706; }
.pub-title {
    font-weight: 700;
    display: block;
    margin-bottom: 0.35rem;
    line-height: 1.5;
    font-size: 1rem;
}
/* 논문 제목 링크 — 기본 밑줄 + ↗ 아이콘으로 클릭 가능 표시 */
.pub-title a {
    color: var(--text-main);
    border-bottom: 1px solid #cbd5e1;
    padding-bottom: 1px;
    transition: color 0.2s, border-color 0.2s;
}
.pub-title a:hover { color: var(--accent); border-bottom-color: var(--accent); }
.pub-title a::after {
    content: ' ↗';
    font-size: 0.78em;
    color: #94a3b8;
    font-weight: 500;
    transition: color 0.2s;
}
.pub-title a:hover::after { color: var(--accent); }
.pub-authors { color: var(--text-light); font-size: 0.87rem; margin-bottom: 0.25rem; }
.pub-authors .me { color: var(--text-main); font-weight: 600; text-decoration: underline; text-underline-offset: 2px; }
.pub-venue { color: var(--accent); font-size: 0.85rem; font-weight: 600; font-style: italic; }

/* 논문 이미지 버튼 */
.pub-thumb {
    flex-shrink: 0;
    width: 264px;
    height: 176px;
    border: 1.5px solid var(--border-color);
    border-radius: 10px;
    position: relative;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    background: #f8fafc;
    color: #94a3b8;
    font-size: 0.65rem;
    font-weight: 600;
    gap: 0.3rem;
    transition: all 0.22s;
    text-decoration: none;
    text-align: center;
    overflow: hidden;
    cursor: pointer;
}
.pub-thumb:hover {
    border-color: var(--accent);
    box-shadow: 0 6px 20px rgba(37,99,235,0.18);
    transform: translateY(-3px);
}
/* hover 시 "View Paper ↗" 오버레이 */
.pub-thumb::after {
    content: 'View Paper  ↗';
    position: absolute;
    inset: 0;
    background: rgba(30, 64, 175, 0.82);
    color: #fff;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.82rem;
    font-weight: 700;
    letter-spacing: 0.03em;
    border-radius: 9px;
    opacity: 0;
    transition: opacity 0.22s;
}
.pub-thumb:hover::after { opacity: 1; }
.pub-thumb img { width: 100%; height: 100%; object-fit: cover; border-radius: 9px; }
.pub-thumb .material-symbols-outlined { font-size: 2rem; }

/* ── 프로필 이미지 라이트박스 ── */
.profile-img {
    cursor: zoom-in;
}
.profile-img:hover {
    box-shadow: 0 6px 32px rgba(37,99,235,0.22), 0 1px 4px rgba(0,0,0,0.1);
    transform: scale(1.03);
    transition: transform 0.22s, box-shadow 0.22s;
}
#img-lightbox {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(15, 23, 42, 0.82);
    backdrop-filter: blur(6px);
    z-index: 9999;
    align-items: center;
    justify-content: center;
    cursor: zoom-out;
    animation: lb-fade-in 0.22s ease;
}
#img-lightbox.open { display: flex; }
@keyframes lb-fade-in {
    from { opacity: 0; }
    to   { opacity: 1; }
}
#img-lightbox img {
    max-width: min(480px, 88vw);
    max-height: 88vh;
    border-radius: 16px;
    box-shadow: 0 24px 64px rgba(0,0,0,0.45);
    object-fit: cover;
    animation: lb-scale-in 0.22s ease;
    cursor: default;
}
@keyframes lb-scale-in {
    from { transform: scale(0.88); opacity: 0; }
    to   { transform: scale(1);    opacity: 1; }
}
#lb-close {
    position: absolute;
    top: 1.2rem; right: 1.4rem;
    width: 38px; height: 38px;
    border-radius: 50%;
    background: rgba(255,255,255,0.15);
    border: none;
    color: #fff;
    font-size: 1.3rem;
    line-height: 1;
    cursor: pointer;
    display: flex; align-items: center; justify-content: center;
    transition: background 0.18s;
}
#lb-close:hover { background: rgba(255,255,255,0.28); }

/* ── 실적 컬럼 스타일 ── */
.col-left .pub-section { margin-bottom: 2rem; }
.col-left .pub-item { flex-direction: column; align-items: flex-start; gap: 0.8rem; padding: 1rem; margin-bottom: 0.8rem; }
.col-left .pub-thumb { width: 100%; height: 160px; }
.col-left .pub-category { font-size: 0.88rem; margin: 1.2rem 0 0.6rem 0; }

/* ── 반응형 ── */
@media (max-width: 1100px) {
    .two-col { flex-direction: column; }
    .col-left { order: -1; }
    .col-right { order: 0; width: 100%; }
    .col-left .pub-item { flex-direction: row; align-items: center; gap: 1.5rem; padding: 1.1rem 1.2rem; }
    .col-left .pub-thumb { width: 264px; height: 176px; }
    .container { max-width: 1000px; }
}
@media (max-width: 768px) {
    .profile-section { flex-direction: column; align-items: center; text-align: center; }
    .profile-info { width: 100%; }
    .keyword-box, .btn-group { justify-content: center; }
    .areas-grid { grid-template-columns: 1fr; }
    .skills-grid { grid-template-columns: repeat(2, 1fr); }
    .pub-item { flex-direction: column; align-items: flex-start; }
    .pub-thumb { width: 100%; height: 180px; }
}