/* =============================================================================
 *  VIPL Lab — Stylesheet
 *  디자인을 바꾸고 싶으면 아래 :root 의 색상 값만 바꿔도 전체 톤이 바뀝니다.
 * ========================================================================== */

:root {
  /* 브랜드 색상 — 이 값만 바꿔도 사이트 전체 색이 바뀝니다 */
  --brand:        #1d4ed8;   /* 선명한 파랑 (제목/푸터) */
  --brand-2:      #2563eb;   /* 밝은 파랑 (링크/버튼) */
  --accent:       #38bdf8;   /* 포인트 하늘색 */

  --bg:           #ffffff;
  --bg-soft:      #f3f7ff;   /* 아주 옅은 파랑 배경 */
  --bg-hero:      linear-gradient(135deg, #2563eb 0%, #38bdf8 100%);
  --text:         #182130;
  --text-muted:   #5b6675;
  --border:       #e2e8f5;
  --card-shadow:  0 1px 3px rgba(16,24,40,.06), 0 6px 20px rgba(16,24,40,.05);

  --maxw: 1120px;
  --radius: 14px;
  --font: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
          "Helvetica Neue", "Apple SD Gothic Neo", "Malgun Gothic", sans-serif;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: var(--font);
  color: var(--text);
  background: var(--bg);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--brand-2); text-decoration: none; }
a:hover { text-decoration: underline; }

.container {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0 24px;
}

/* ---------------------------------------------------------------- Header/Nav */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(255,255,255,.92);
  backdrop-filter: saturate(180%) blur(10px);
  border-bottom: 1px solid var(--border);
}
.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 68px;
}
.brand {
  display: flex;
  align-items: baseline;
  gap: 10px;
  font-weight: 800;
  font-size: 1.25rem;
  color: var(--brand);
  letter-spacing: -.02em;
}
.brand:hover { text-decoration: none; }
.brand .brand-full {
  font-size: .8rem;
  font-weight: 500;
  color: var(--text-muted);
  letter-spacing: 0;
}
.nav-links {
  display: flex;
  gap: 4px;
  list-style: none;
  margin: 0;
  padding: 0;
}
.nav-links a {
  display: block;
  padding: 8px 14px;
  border-radius: 8px;
  color: var(--text);
  font-weight: 500;
  font-size: .95rem;
  transition: background .15s, color .15s;
}
.nav-links a:hover { background: var(--bg-soft); text-decoration: none; }
.nav-links a.active { color: var(--brand-2); background: #eef4fb; }

.nav-toggle {
  display: none;
  background: none;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 6px 10px;
  font-size: 1.3rem;
  cursor: pointer;
  color: var(--brand);
}

@media (max-width: 760px) {
  .nav-toggle { display: block; }
  .nav-links {
    position: absolute;
    top: 68px; left: 0; right: 0;
    flex-direction: column;
    gap: 0;
    background: #fff;
    border-bottom: 1px solid var(--border);
    padding: 8px 16px 16px;
    display: none;
  }
  .nav-links.open { display: flex; }
  .nav-links a { padding: 12px 10px; }
  .brand .brand-full { display: none; }
}

/* ------------------------------------------------------------------- Hero */
.hero {
  background: var(--bg-hero);
  color: #fff;
  padding: 64px 0 68px;
  position: relative;
  overflow: hidden;
}
.hero::after {
  content: "";
  position: absolute;
  right: -120px; top: -120px;
  width: 420px; height: 420px;
  background: radial-gradient(circle, rgba(56,189,248,.35), transparent 70%);
  border-radius: 50%;
}
.hero h1 {
  font-size: clamp(1.7rem, 4vw, 2.6rem);
  line-height: 1.15;
  margin: 0 0 16px;
  letter-spacing: -.02em;
}
.hero p {
  font-size: clamp(1.05rem, 2vw, 1.3rem);
  color: rgba(255,255,255,.9);
  max-width: 52ch;
  margin: 0 0 32px;
}
.hero-buttons { display: flex; gap: 14px; flex-wrap: wrap; }

/* ------------------------------------------------------------------- Buttons */
.btn {
  display: inline-block;
  padding: 12px 24px;
  border-radius: 10px;
  font-weight: 600;
  font-size: .98rem;
  cursor: pointer;
  transition: transform .12s, box-shadow .15s, background .15s;
}
.btn:hover { text-decoration: none; transform: translateY(-1px); }
.btn-primary { background: #fff; color: var(--brand); }
.btn-primary:hover { box-shadow: 0 8px 24px rgba(0,0,0,.18); }
.btn-ghost {
  background: rgba(255,255,255,.12);
  color: #fff;
  border: 1px solid rgba(255,255,255,.4);
}
.btn-ghost:hover { background: rgba(255,255,255,.2); }

/* ------------------------------------------------------------------ Sections */
.section { padding: 72px 0; }
.section.alt { background: var(--bg-soft); }
.section-head { max-width: 640px; margin: 0 0 40px; }
.section-head.center { margin-left: auto; margin-right: auto; text-align: center; }
.eyebrow {
  text-transform: uppercase;
  letter-spacing: .12em;
  font-size: .78rem;
  font-weight: 700;
  color: var(--brand-2);
  margin: 0 0 10px;
}
h2.section-title {
  font-size: clamp(1.6rem, 3vw, 2.2rem);
  letter-spacing: -.02em;
  margin: 0 0 14px;
  color: var(--text);
}
.section-head p { color: var(--text-muted); font-size: 1.08rem; margin: 0; }

.page-hero {
  background: var(--bg-soft);
  border-bottom: 1px solid var(--border);
  padding: 56px 0;
}
.page-hero h1 {
  font-size: clamp(1.8rem, 4vw, 2.6rem);
  margin: 0 0 10px;
  letter-spacing: -.02em;
}
.page-hero p { color: var(--text-muted); font-size: 1.1rem; margin: 0; max-width: 60ch; }

.prose p { color: var(--text); font-size: 1.08rem; margin: 0 0 18px; }
.prose p:last-child { margin-bottom: 0; }

/* --------------------------------------------------------------------- Stats */
.stats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 20px;
  margin-top: 44px;
}
.stat {
  text-align: center;
  padding: 26px 16px;
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius);
}
.stat .num {
  font-size: 2.2rem; font-weight: 800; color: var(--brand-2);
  line-height: 1; letter-spacing: -.02em;
}
.stat .lbl { color: var(--text-muted); font-size: .95rem; margin-top: 8px; }

/* --------------------------------------------------------------------- Cards */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 22px;
}
.card {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px;
  box-shadow: var(--card-shadow);
  transition: transform .15s, box-shadow .15s;
}
.card:hover { transform: translateY(-3px); box-shadow: 0 10px 30px rgba(16,24,40,.1); }
.card .icon { font-size: 2rem; margin-bottom: 14px; }
.card h3 { margin: 0 0 10px; font-size: 1.2rem; letter-spacing: -.01em; }
.card p { margin: 0; color: var(--text-muted); }

/* ---------------------------------------------------------------- People */
.people-group { margin-bottom: 48px; }
.people-group h3 {
  font-size: 1.35rem;
  margin: 0 0 22px;
  padding-bottom: 10px;
  border-bottom: 2px solid var(--border);
}
.people-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 24px;
}
.person { text-align: center; }
.person .avatar {
  width: 128px; height: 128px;
  border-radius: 50%;
  margin: 0 auto 14px;
  object-fit: cover;
  background: var(--bg-hero);
  display: flex; align-items: center; justify-content: center;
  color: #fff; font-size: 2.2rem; font-weight: 700;
  border: 4px solid #fff;
  box-shadow: var(--card-shadow);
}
.person .name { font-weight: 700; font-size: 1.05rem; }
.person .role { color: var(--brand-2); font-size: .9rem; margin-top: 2px; }
.person .note { color: var(--text-muted); font-size: .88rem; margin-top: 6px; }

/* Professor card (larger, horizontal) */
.prof-card {
  display: grid;
  grid-template-columns: 200px 1fr;
  gap: 36px;
  align-items: start;
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 36px;
  box-shadow: var(--card-shadow);
  margin-bottom: 56px;
}
.prof-card .avatar { width: 180px; height: 180px; font-size: 3rem; }
.prof-card h3 { margin: 0 0 4px; font-size: 1.6rem; }
.prof-card .prof-title { color: var(--brand-2); font-weight: 600; margin: 0 0 4px; }
.prof-card .prof-meta { color: var(--text-muted); font-size: .95rem; margin: 0 0 16px; }
.prof-card .prof-bio { color: var(--text); margin: 0 0 18px; }
.tags { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 16px; }
.tag {
  background: #eef4fb; color: var(--brand-2);
  padding: 5px 12px; border-radius: 100px;
  font-size: .82rem; font-weight: 600;
}
.inline-links { display: flex; gap: 16px; flex-wrap: wrap; }
@media (max-width: 620px) {
  .prof-card { grid-template-columns: 1fr; text-align: center; }
  .prof-card .avatar { margin: 0 auto; }
  .tags, .inline-links { justify-content: center; }
}

/* --------------------------------------------- People: clickable prof card */
.prof-kr { color: var(--text-muted); font-weight: 500; font-size: 1.1rem; }
.prof-card-link {
  text-decoration: none;
  color: inherit;
  cursor: pointer;
}
.prof-card-link:hover {
  text-decoration: none;
  transform: translateY(-3px);
  box-shadow: 0 12px 34px rgba(16,24,40,.14);
  border-color: var(--brand-2);
}
.view-profile {
  display: inline-block;
  margin-top: 16px;
  color: var(--brand-2);
  font-weight: 600;
  font-size: .95rem;
}
.prof-card-link:hover .view-profile { text-decoration: underline; }

/* People: Alumni call-to-action banner */
.alumni-cta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  margin-top: 8px;
  padding: 22px 28px;
  border-radius: var(--radius);
  background: linear-gradient(135deg, #eaf2ff 0%, #dbeafe 100%);
  border: 1px solid var(--border);
  text-decoration: none;
  transition: transform .15s, box-shadow .15s;
}
.alumni-cta:hover {
  text-decoration: none;
  transform: translateY(-2px);
  box-shadow: 0 10px 28px rgba(37,99,235,.18);
}
.alumni-cta-eyebrow {
  display: block;
  text-transform: uppercase;
  letter-spacing: .12em;
  font-size: .74rem;
  font-weight: 700;
  color: var(--brand-2);
}
.alumni-cta-title { display: block; font-size: 1.25rem; font-weight: 700; color: var(--brand); }
.alumni-cta-arrow { font-size: 1.6rem; color: var(--brand-2); }

/* ---------------------------------------------- Professor detail page */
.back-link {
  display: inline-block;
  margin-bottom: 24px;
  color: var(--brand-2);
  font-weight: 600;
  font-size: .92rem;
}
.prof-detail {
  display: grid;
  grid-template-columns: 240px 1fr;
  gap: 44px;
  align-items: start;
}
.prof-detail-side { position: sticky; top: 92px; text-align: center; }
.avatar.prof-detail-avatar {
  width: 220px; height: 220px; font-size: 3.6rem; margin: 0 auto 20px;
}
.prof-detail-links { display: flex; flex-direction: column; gap: 10px; }
.btn-link {
  display: block;
  padding: 10px 16px;
  border: 1px solid var(--border);
  border-radius: 10px;
  font-weight: 600;
  font-size: .92rem;
  color: var(--brand-2);
  background: #fff;
  transition: background .15s, border-color .15s;
}
.btn-link:hover { background: #eef4ff; border-color: var(--brand-2); text-decoration: none; }
.prof-detail-main h1 {
  font-size: clamp(1.8rem, 3.5vw, 2.4rem);
  margin: 0 0 6px;
  letter-spacing: -.02em;
}
.prof-detail-main .prof-title { font-size: 1.15rem; margin: 0 0 4px; }
.prof-contact {
  display: flex; flex-wrap: wrap; gap: 8px 22px;
  margin: 14px 0 4px; color: var(--text-muted); font-size: .95rem;
}
.prof-detail-bio { margin-top: 18px; }
.cv-block { margin-top: 34px; }
.cv-title {
  font-size: 1.25rem;
  margin: 0 0 14px;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--border);
  color: var(--brand);
}
.cv-row {
  display: grid;
  grid-template-columns: 130px 1fr;
  gap: 18px;
  padding: 10px 0;
}
.cv-year { color: var(--brand-2); font-weight: 600; font-size: .92rem; }
.cv-main strong { display: block; font-weight: 700; }
.cv-org { color: var(--text-muted); font-size: .94rem; }
.cv-awards { margin: 0; padding-left: 20px; }
.cv-awards li { margin: 6px 0; }
@media (max-width: 720px) {
  .prof-detail { grid-template-columns: 1fr; gap: 28px; }
  .prof-detail-side { position: static; }
  .avatar.prof-detail-avatar { width: 160px; height: 160px; font-size: 2.8rem; }
  .cv-row { grid-template-columns: 1fr; gap: 2px; }
}

/* -------------------------------------------------------- Alumni page */
.alum-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 24px;
}
.alum-card {
  text-align: center;
  padding: 30px 20px 26px;
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--card-shadow);
  transition: transform .15s, box-shadow .15s;
}
.alum-card:hover { transform: translateY(-4px); box-shadow: 0 12px 32px rgba(16,24,40,.12); }
.avatar.alum-avatar { width: 96px; height: 96px; font-size: 1.7rem; margin: 0 auto 14px; }
.alum-name { font-weight: 700; font-size: 1.08rem; }
.alum-badge {
  display: inline-block;
  margin-top: 8px;
  padding: 3px 12px;
  border-radius: 100px;
  font-size: .78rem;
  font-weight: 700;
  letter-spacing: .02em;
}
.alum-badge.phd { background: #ede9fe; color: #6d28d9; }
.alum-badge.ms  { background: #dbeafe; color: var(--brand-2); }
.alum-pos { margin-top: 10px; color: var(--text); font-size: .92rem; }
.alum-note { margin-top: 4px; color: var(--text-muted); font-size: .86rem; }

/* ----------------------------------------------------------- Publications */
.pub-year { margin-bottom: 40px; }
.pub-year > h3 {
  font-size: 1.4rem; color: var(--brand);
  margin: 0 0 18px; padding-bottom: 8px;
  border-bottom: 2px solid var(--border);
}
.pub {
  padding: 18px 0;
  border-bottom: 1px solid var(--border);
}
.pub:last-child { border-bottom: none; }
.pub .pub-title { font-weight: 700; font-size: 1.05rem; margin: 0 0 4px; }
.pub .pub-authors { color: var(--text); margin: 0 0 2px; font-size: .96rem; }
.pub .pub-authors .me { font-weight: 700; color: var(--brand); }
.pub .pub-venue { color: var(--text-muted); font-style: italic; font-size: .94rem; }
.pub .pub-links { margin-top: 8px; display: flex; gap: 10px; flex-wrap: wrap; }
.pub .pub-links a {
  font-size: .82rem; font-weight: 600;
  padding: 3px 12px; border: 1px solid var(--border);
  border-radius: 100px; color: var(--brand-2);
}
.pub .pub-links a:hover { background: #eef4fb; text-decoration: none; }

/* ------------------------------------------------------------------ News */
.timeline { max-width: 760px; }
.news-item {
  display: grid;
  grid-template-columns: 130px 1fr;
  gap: 24px;
  padding: 22px 0;
  border-bottom: 1px solid var(--border);
}
.news-item:last-child { border-bottom: none; }
.news-item .date { color: var(--brand-2); font-weight: 600; font-size: .92rem; }
.news-item h3 { margin: 0 0 6px; font-size: 1.12rem; }
.news-item p { margin: 0; color: var(--text-muted); }
@media (max-width: 560px) {
  .news-item { grid-template-columns: 1fr; gap: 4px; }
}

/* -------------------------------------------------------------- Teaching */
.course {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 6px 18px;
  align-items: baseline;
  padding: 22px 0;
  border-bottom: 1px solid var(--border);
}
.course:last-child { border-bottom: none; }
.course .course-code {
  grid-row: span 2;
  align-self: start;
  background: #eef4ff;
  color: var(--brand-2);
  font-weight: 700;
  font-size: .85rem;
  padding: 8px 14px;
  border-radius: 10px;
  white-space: nowrap;
}
.course .course-title { font-weight: 700; font-size: 1.12rem; margin: 0; }
.course .course-title .course-term {
  font-weight: 500; color: var(--text-muted); font-size: .9rem; margin-left: 10px;
}
.course .course-title .course-level {
  display: inline-block; margin-left: 8px;
  font-size: .72rem; font-weight: 700; letter-spacing: .04em;
  text-transform: uppercase; color: var(--accent);
  border: 1px solid var(--accent); border-radius: 100px; padding: 1px 9px;
  vertical-align: middle;
}
.course .course-desc { grid-column: 2; margin: 0; color: var(--text-muted); }
@media (max-width: 560px) {
  .course { grid-template-columns: 1fr; }
  .course .course-code { grid-row: auto; justify-self: start; }
  .course .course-desc { grid-column: 1; }
}

/* ---------------------------------------------------------------- Photos */
.photo-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 20px;
}
.photo {
  border-radius: var(--radius);
  overflow: hidden;
  border: 1px solid var(--border);
  background: #fff;
  box-shadow: var(--card-shadow);
  transition: transform .15s, box-shadow .15s;
}
.photo:hover { transform: translateY(-3px); box-shadow: 0 10px 30px rgba(16,24,40,.12); }
.photo .frame {
  aspect-ratio: 4 / 3;
  width: 100%;
  object-fit: cover;
  display: block;
}
.photo .placeholder {
  aspect-ratio: 4 / 3;
  display: flex; align-items: center; justify-content: center;
  background: linear-gradient(135deg, #eaf2ff 0%, #dbeafe 100%);
  color: var(--brand-2); font-size: 2.4rem;
}
.photo .caption {
  padding: 12px 16px; font-size: .92rem; color: var(--text-muted);
}

/* --------------------------------------------------------------- Contact */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 40px;
}
@media (max-width: 720px) { .contact-grid { grid-template-columns: 1fr; } }
.contact-list { list-style: none; padding: 0; margin: 0; }
.contact-list li {
  display: flex; gap: 14px; align-items: flex-start;
  padding: 14px 0; border-bottom: 1px solid var(--border);
}
.contact-list li:last-child { border-bottom: none; }
.contact-list .ci { font-size: 1.3rem; line-height: 1.4; }
.contact-list .ck { font-weight: 600; display: block; }
.contact-list .cv { color: var(--text-muted); }

/* ------------------------------------------------------- Home: Notice */
.notice-list { max-width: 1150px; }
.notice-item { padding: 4px 0 20px; }
.notice-item h3 {
  font-size: 1.12rem; margin: 0 0 8px; color: var(--brand);
}
.notice-item p { margin: 0; color: var(--text); }
.notice-item ul { margin: 0; padding-left: 20px; color: var(--text); }
.notice-item ul li { margin: 4px 0; }

/* --------------------------------------------------------- Home: News */
.news-list { max-width: 900px; }
.news-row {
  display: grid;
  grid-template-columns: 110px 1fr;
  gap: 18px;
  padding: 11px 0;
  border-bottom: 1px solid var(--border);
}
.news-row:last-child { border-bottom: none; }
.news-date { color: var(--brand-2); font-weight: 600; font-size: .92rem; white-space: nowrap; }
.news-text { color: var(--text); }
.news-text strong { color: var(--brand); font-weight: 700; }
.news-text a { font-weight: 600; }
@media (max-width: 560px) {
  .news-row { grid-template-columns: 1fr; gap: 2px; }
}
/* 10개 초과 항목은 기본 숨김, "More" 클릭 시 표시 */
.news-hidden { display: none; }
.news-list.expanded .news-hidden { display: grid; }
.more-wrap { margin-top: 20px; }
.more-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: #eef4ff;
  color: var(--brand-2);
  border: 1px solid var(--border);
  border-radius: 100px;
  padding: 9px 22px;
  font-size: .92rem;
  font-weight: 600;
  font-family: inherit;
  cursor: pointer;
  transition: background .15s, border-color .15s;
}
.more-btn:hover { background: #e0ecff; border-color: var(--brand-2); }
.more-btn .chev { font-size: .8rem; line-height: 1; }

/* --------------------------------------------------------- Home: Logo */
#home-logo { padding: 8px 0 56px; }
.home-logo-wrap { display: flex; justify-content: center; }
.home-logo {
  width: 260px;
  max-width: 60%;
  height: auto;
}
@media (max-width: 560px) {
  .home-logo-wrap { justify-content: center; }
  .home-logo { max-width: 80%; }
}

/* ------------------------------------------------------------------ Footer */
.site-footer {
  background: var(--brand);
  color: rgba(255,255,255,.82);
  padding: 44px 0 32px;
  margin-top: 0;
}
.site-footer a { color: #fff; }
.footer-inner {
  display: flex; justify-content: space-between;
  gap: 24px; flex-wrap: wrap;
}
.footer-brand { font-weight: 800; font-size: 1.15rem; color: #fff; margin-bottom: 6px; }
.footer-inner p { margin: 4px 0; font-size: .92rem; }
.footer-links { display: flex; gap: 18px; flex-wrap: wrap; }
.footer-bottom {
  margin-top: 28px; padding-top: 20px;
  border-top: 1px solid rgba(255,255,255,.15);
  font-size: .85rem; color: rgba(255,255,255,.6);
}

.empty-hint {
  color: var(--text-muted);
  background: var(--bg-soft);
  border: 1px dashed var(--border);
  border-radius: var(--radius);
  padding: 20px;
  text-align: center;
}