:root {
  color-scheme: light;
  --page-bg: #fafafa;
  --panel: #ffffff;
  --text: #111827;
  --muted: #5b6472;
  --line: #d7dce2;
  --accent: #1d4ed8;
  --accent-soft: #eff4ff;
  --shadow: 0 20px 40px rgba(15, 23, 42, 0.12);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--page-bg);
  color: var(--text);
  font-family: "Lato", "Noto Sans KR", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  line-height: 1.7;
}

a {
  color: inherit;
  text-decoration: none;
}

button {
  font: inherit;
}

.page {
  width: min(1180px, calc(100vw - 48px));
  margin: 0 auto;
  padding: 24px 0 64px;
}

.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  padding-bottom: 24px;
  border-bottom: 1px solid var(--line);
}

.topnav {
  display: flex;
  flex-wrap: wrap;
  gap: 28px;
}

.topnav a {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--muted);
}

.topnav a:hover,
.topnav a:focus-visible {
  color: var(--accent);
}

.topnav a.is-active {
  color: var(--text);
  font-weight: 700;
}

.lang-toggle {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 8px 14px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: #fff;
  color: var(--muted);
  cursor: pointer;
}

.lang-option {
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.08em;
}

.lang-separator {
  width: 1px;
  height: 13px;
  background: var(--line);
}

.lang-toggle[data-active-lang="en"] [data-lang-option="en"],
.lang-toggle[data-active-lang="ko"] [data-lang-option="ko"] {
  color: var(--accent);
}

.hero-layout {
  display: grid;
  grid-template-columns: 240px minmax(0, 1fr);
  gap: 44px;
  align-items: center;
  padding-top: 42px;
  padding-bottom: 22px;
}

.profile-column {
  display: grid;
  gap: 16px;
  align-self: start;
  justify-items: center;
}

.profile-photo-button {
  position: relative;
  width: 220px;
  border: 0;
  border-radius: 24px;
  padding: 0;
  background: transparent;
  box-shadow: var(--shadow);
  cursor: pointer;
  overflow: hidden;
}

.profile-photo-button img {
  display: block;
  width: 100%;
  height: auto;
  cursor: pointer;
}

.thumbs-pop {
  position: absolute;
  top: 50%;
  left: 50%;
  font-size: 2.6rem;
  opacity: 0;
  pointer-events: none;
  transform: translate(-50%, -30%) scale(0.5);
  filter: drop-shadow(0 8px 12px rgba(0, 0, 0, 0.25));
}

.thumbs-pop.is-active {
  animation: thumbs-burst 0.9s ease-out forwards;
}

@keyframes thumbs-burst {
  0% {
    transform: translate(-50%, -30%) scale(0.4) rotate(0deg);
    opacity: 0;
  }

  25% {
    transform: translate(-50%, -70%) scale(1.05) rotate(-12deg);
    opacity: 1;
  }

  55% {
    transform: translate(-46%, -105%) scale(1) rotate(10deg);
    opacity: 1;
  }

  100% {
    transform: translate(-50%, -160%) scale(1) rotate(0deg);
    opacity: 0;
  }
}

.hero-copy {
  min-width: 0;
}

.hero-eyebrow {
  margin: 0 0 12px;
  font-size: 0.82rem;
  font-weight: 700;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--accent);
}

.hero-title {
  margin: 0;
  font-size: clamp(2.15rem, 4vw, 3.4rem);
  line-height: 1.05;
  letter-spacing: -0.055em;
}

.hero-bullets {
  margin: 22px 0 0;
  padding-left: 20px;
  max-width: 92ch;
  color: var(--text);
  display: grid;
  gap: 8px;
}

.hero-details {
  margin-top: 20px;
  padding-top: 18px;
  border-top: 1px solid var(--line);
}

.hero-details a {
  color: inherit;
  font-weight: 600;
  text-decoration: underline;
  text-underline-offset: 2px;
}

.hero-details strong {
  color: inherit;
  font-weight: 600;
}

.hero-details a:hover,
.hero-details a:focus-visible {
  color: inherit;
}

.hero-bullets li::marker,
.about-list li::marker {
  color: var(--accent);
}

.contact-links {
  width: 88%;
  max-width: 240px;
  display: grid;
  gap: 4px;
}

.contact-icon-link {
  display: grid;
  grid-template-columns: 22px minmax(0, 1fr);
  align-items: center;
  gap: 8px;
  width: 100%;
  padding: 2px 0;
  border: 0;
  background: transparent;
  color: var(--muted);
  transition: transform 0.18s ease, color 0.18s ease;
}

.contact-icon-shell {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 22px;
  height: 22px;
  color: var(--accent);
}

.contact-icon-link svg {
  width: 16px;
  height: 16px;
  fill: currentColor;
}

.contact-link-text {
  min-width: 0;
  font-size: 0.86rem;
  font-weight: 500;
  color: inherit;
  line-height: 1.35;
  overflow-wrap: anywhere;
}

.contact-icon-link:hover,
.contact-icon-link:focus-visible {
  color: var(--accent);
  transform: translateY(-1px) scale(1.01);
}

.copy-toast {
  position: fixed;
  left: 50%;
  bottom: 28px;
  z-index: 1200;
  padding: 9px 14px;
  border-radius: 999px;
  background: rgba(17, 24, 39, 0.92);
  color: #fff;
  font-size: 0.86rem;
  font-weight: 600;
  line-height: 1.2;
  transform: translate(-50%, 10px);
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.18s ease, transform 0.18s ease;
  box-shadow: 0 14px 28px rgba(15, 23, 42, 0.22);
}

.copy-toast.is-visible {
  opacity: 1;
  transform: translate(-50%, 0);
}

.scholar-link svg {
  width: 20px;
  height: 20px;
}

.section {
  padding: 32px 0;
  border-top: 1px solid var(--line);
}

.section-title {
  margin: 0;
  font-size: 1.45rem;
  line-height: 1.2;
  letter-spacing: -0.05em;
}

.section-title-row {
  display: flex;
  align-items: center;
  gap: 10px;
}

.section-title-link {
  display: inline-flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  width: fit-content;
  max-width: 100%;
  border-radius: 999px;
  color: var(--text);
  cursor: pointer;
  transition: color 0.18s ease;
}

.section-title-link .section-title {
  min-width: 0;
}

.section-title-link-cta {
  display: inline-flex;
  align-items: center;
  min-height: 28px;
  padding: 3px 10px;
  border: 1px solid rgba(29, 78, 216, 0.2);
  border-radius: 999px;
  background: var(--accent-soft);
  color: var(--accent);
  font-size: 0.78rem;
  font-weight: 700;
  line-height: 1;
  white-space: nowrap;
}

.section-title-link-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 20px;
  height: 20px;
  color: var(--accent);
  opacity: 1;
  transform: translateX(0);
  transition: opacity 0.18s ease, transform 0.18s ease, color 0.18s ease;
}

.section-title-link-button svg {
  width: 20px;
  height: 20px;
}

.section-title-link:hover .section-title-link-button,
.section-title-link:focus-visible .section-title-link-button,
.section-title-row-link:focus-within .section-title-link-button {
  opacity: 1;
  transform: translateX(3px);
}

.section-title-link:hover,
.section-title-link:focus-visible {
  color: var(--accent);
}

.section-title-link:hover .section-title-link-button,
.section-title-link:focus-visible .section-title-link-button {
  color: var(--accent);
}

.section-title-link:focus-visible {
  outline: 3px solid rgba(29, 78, 216, 0.22);
  outline-offset: 6px;
}

.about-list {
  margin: 18px 0 0;
  padding-left: 20px;
  display: grid;
  gap: 10px;
  color: var(--text);
}

.about-list strong,
.entry-text strong {
  color: var(--text);
  font-weight: 700;
}

.entry-list {
  margin-top: 18px;
  display: grid;
  gap: 20px;
}

.project-legend {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 14px;
  margin-top: 16px;
}

.project-legend-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 12px;
  border-radius: 999px;
  background: #eef2f7;
  color: var(--text);
  font-size: 0.86rem;
  font-weight: 600;
}

.project-legend-icon {
  font-size: 0.9rem;
  line-height: 1;
}

.entry-date {
  display: block;
  margin-bottom: 6px;
  font-size: 0.82rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--accent);
}

.entry-text {
  margin: 0;
  color: var(--text);
  font-size: 1rem;
}

.project-title-row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0 8px;
}

.project-title-text {
  min-width: 0;
}

.project-meta {
  margin: 4px 0 0;
  color: var(--text);
  font-size: 0.95rem;
  font-weight: 400;
  line-height: 1.6;
}

.project-meta strong {
  color: var(--text);
  font-weight: 700;
}

.entry-bullet-line,
.patent-line {
  position: relative;
  margin: 0;
  padding-left: 16px;
}

.entry-bullet-line::before,
.patent-line::before {
  content: '•';
  position: absolute;
  left: 0;
  top: 0.24em;
  color: var(--accent);
  font-size: 1em;
  line-height: 1;
}

.patent-meta {
  margin-top: 4px;
  color: var(--muted);
  font-size: 0.95rem;
}

.entry-link {
  display: inline-flex;
  align-items: center;
  margin-left: 10px;
  font-size: 0.92rem;
  font-weight: 700;
  color: var(--accent);
  white-space: nowrap;
}

.skill-groups {
  margin-top: 18px;
  display: grid;
  gap: 18px;
}

.skill-group-title {
  margin: 0 0 12px;
  font-size: 0.95rem;
  font-weight: 700;
  letter-spacing: -0.04em;
}

.tag-list {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.skill-tag {
  display: inline-flex;
  align-items: center;
  padding: 7px 12px;
  border-radius: 999px;
  background: var(--accent-soft);
  color: var(--accent);
  font-size: 0.88rem;
  font-weight: 600;
}

.skill-tag-secondary {
  background: #e5e7eb;
  color: #111111;
}

.footer {
  margin-top: 20px;
  padding-top: 24px;
  border-top: 1px solid var(--line);
  font-size: 0.9rem;
  color: var(--muted);
}

@media (max-width: 640px) {
  .page {
    width: min(100vw - 32px, 1180px);
  }

  .topbar {
    display: grid;
    gap: 16px;
  }

  .lang-toggle {
    width: fit-content;
  }

  .hero-layout {
    grid-template-columns: 1fr;
    gap: 28px;
    padding-top: 32px;
  }

  .profile-photo-button {
    width: 200px;
  }
}