:root {
  --bg: #0b0d1a;
  --bg-2: #11142a;
  --card: #151936;
  --line: #2a2f55;
  --text: #e8eaf6;
  --muted: #98a0c8;
  --accent: #7c7cff;
  --c-found: #4fd1c5;
  --c-luasys: #f6ad55;
  --c-coupang: #7c7cff;
  --c-vroong: #f56ea0;
  --c-hanwha: #63b3ed;
  --c-csquare: #68d391;
  --radius: 14px;
  --mono: 'JetBrains Mono', 'SF Mono', 'Monaco', ui-monospace, monospace;
  --sans: 'Inter', 'Pretendard', -apple-system, 'Segoe UI', 'Noto Sans KR', sans-serif;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--sans);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}
a { color: inherit; }
.wrap { width: min(1080px, 100% - 32px); margin-inline: auto; }

/* language switch: only the active language is shown */
html[data-lang="en"] [lang="ko"],
html[data-lang="ko"] [lang="en"] { display: none !important; }

/* ---------- top bar ---------- */
.topbar {
  position: fixed; inset: 0 0 auto 0; z-index: 50;
  background: rgba(11, 13, 26, .78);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
}
.topbar .wrap { display: flex; align-items: center; justify-content: space-between; height: 54px; }
.brand { font-family: var(--mono); font-size: .95rem; text-decoration: none; }
.brand b { color: var(--c-csquare); font-weight: 400; }
.topnav { display: flex; align-items: center; gap: 18px; font-family: var(--mono); font-size: .82rem; color: var(--muted); }
.topnav a { text-decoration: none; }
.topnav a:hover { color: var(--text); }
.lang { display: flex; gap: 2px; font-family: var(--mono); font-size: .78rem; }
.lang button {
  background: none; border: 1px solid transparent; color: var(--muted);
  padding: 3px 9px; border-radius: 6px; cursor: pointer; font: inherit;
}
.lang button[aria-pressed="true"] { color: var(--accent); border-color: var(--accent); background: rgba(124,124,255,.15); }
@media (max-width: 640px) { .topnav a { display: none; } }

/* ---------- hero ---------- */
.hero {
  padding: 120px 0 70px;
  background:
    radial-gradient(900px 400px at 85% 0%, rgba(124,124,255,.22), transparent 60%),
    radial-gradient(700px 360px at 0% 30%, rgba(79,209,197,.10), transparent 60%);
}
.hero .wrap { display: grid; grid-template-columns: 1fr auto; gap: 48px; align-items: center; }
.eyebrow { font-family: var(--mono); font-size: .85rem; color: var(--c-csquare); margin: 0 0 14px; }
.hero h1 { font-size: clamp(2.4rem, 6vw, 4.2rem); line-height: 1.08; margin: 0 0 8px; letter-spacing: -.02em; }
.hero h1 small { display: block; font-size: .38em; color: var(--muted); font-weight: 500; letter-spacing: 0; margin-top: 10px; }
.tagline { margin: 18px 0 0; font-family: var(--mono); font-size: .9rem; letter-spacing: .02em; color: var(--c-csquare); }
.tagline i { font-style: normal; color: var(--muted); margin: 0 6px; }
.lead { font-size: 1.12rem; color: #c9cdea; max-width: 56ch; margin: 22px 0 28px; }
.stats { display: flex; flex-wrap: wrap; gap: 12px; margin: 0 0 30px; padding: 0; list-style: none; }
.stats li { background: var(--card); border: 1px solid var(--line); border-radius: 12px; padding: 12px 18px; min-width: 112px; }
.stats strong { display: block; font-size: 1.6rem; line-height: 1.1; color: var(--accent); }
.stats span { font-size: .8rem; color: var(--muted); }
.cta { display: flex; flex-wrap: wrap; gap: 10px; }
.btn {
  display: inline-block; padding: 10px 18px; border-radius: 10px; text-decoration: none;
  font-size: .92rem; border: 1px solid var(--line); background: var(--card);
}
.btn.primary { background: var(--accent); border-color: var(--accent); color: #0b0d1a; font-weight: 600; }
.btn:hover { filter: brightness(1.12); }
.portrait {
  width: 260px; height: 260px; border-radius: 50%;
  object-fit: cover; object-position: 80% 42%;
  border: 3px solid var(--accent);
  box-shadow: 0 0 0 10px rgba(124,124,255,.12), 0 0 60px rgba(124,124,255,.35);
}
@media (max-width: 820px) {
  .hero { padding-top: 96px; }
  .hero .wrap { grid-template-columns: 1fr; text-align: left; }
  .portrait { order: -1; width: 150px; height: 150px; }
}

/* ---------- section heads ---------- */
section { padding: 70px 0; }
.sec-head { margin-bottom: 34px; }
.sec-head h2 { font-size: clamp(1.7rem, 3.6vw, 2.3rem); margin: 0 0 6px; letter-spacing: -.01em; }
.sec-head p { margin: 0; color: var(--muted); max-width: 60ch; }
.journey .sec-head p { max-width: none; }

/* ---------- journey map ---------- */
.journey { background: var(--bg-2); border-block: 1px solid var(--line); }

/* one row per chapter: date | node on the axis | card */
.map { position: relative; --date-w: 150px; --axis-w: 48px; }
.map::before {
  content: ''; position: absolute; top: 12px; bottom: 12px;
  left: calc(var(--date-w) + var(--axis-w) / 2 - 1px); width: 2px;
  background: linear-gradient(to bottom, transparent, var(--line) 4%, var(--line) 92%, var(--c-csquare));
}
.stop { position: relative; display: grid; grid-template-columns: var(--date-w) var(--axis-w) 1fr; margin-bottom: 28px; }
.stop:last-child { margin-bottom: 0; }

.stop-date { text-align: right; padding-top: 18px; display: flex; flex-direction: column; gap: 2px; }
.stop-date b { font-size: 2.1rem; line-height: 1; font-weight: 800; letter-spacing: -.03em; color: var(--text); }
.stop-date > span { font-family: var(--mono); font-size: .76rem; color: var(--muted); }
.stop-date .place { opacity: .7; }

.stop-node { position: relative; }
.stop-node::before {
  content: ''; position: absolute; left: 50%; top: 26px; translate: -50% 0;
  width: 14px; height: 14px; border-radius: 50%;
  background: var(--c); box-shadow: 0 0 0 5px var(--bg-2), 0 0 0 6px var(--line);
}
.stop.now .stop-node::before { animation: pulse 2s infinite; }
.stop.now .stop-date b { color: var(--c-csquare); }
@keyframes pulse {
  0% { box-shadow: 0 0 0 5px var(--bg-2), 0 0 0 6px var(--c-csquare), 0 0 0 6px rgba(104,211,145,.5); }
  100% { box-shadow: 0 0 0 5px var(--bg-2), 0 0 0 6px var(--c-csquare), 0 0 0 18px rgba(104,211,145,0); }
}

.card {
  background: linear-gradient(180deg, rgba(255,255,255,.035), rgba(255,255,255,0) 60%), var(--card);
  border: 1px solid var(--line); border-radius: var(--radius); padding: 22px 24px;
  box-shadow: 0 1px 0 rgba(255,255,255,.04) inset, 0 12px 30px -18px rgba(0,0,0,.6);
  transition: border-color .25s, box-shadow .25s, transform .25s;
}
.card:hover {
  border-color: color-mix(in srgb, var(--c) 55%, var(--line));
  box-shadow: 0 0 0 1px color-mix(in srgb, var(--c) 25%, transparent), 0 18px 40px -20px color-mix(in srgb, var(--c) 45%, transparent);
  transform: translateY(-2px);
}
.card-head { display: flex; align-items: center; gap: 14px; margin-bottom: 14px; }
/* company tile: same white tile for every chapter — a logo image, or the name set as a wordmark */
.logo {
  flex: none; display: grid; place-items: center; width: 112px; height: 48px; padding: 8px 12px;
  border-radius: 12px; background: #fff; border: 1px solid rgba(255,255,255,.12);
  box-shadow: 0 6px 16px -10px rgba(0,0,0,.6); overflow: hidden;
}
.logo img { display: block; max-width: 100%; max-height: 100%; width: auto; height: auto; object-fit: contain; }
.logo.word { font-weight: 800; font-size: 1rem; line-height: 1.05; letter-spacing: -.02em; color: #1b1f3b; text-align: center; }
.logo.word small { display: block; font-size: .72rem; font-weight: 700; letter-spacing: 0; }
.co-link { text-decoration: none; border-bottom: 1px solid color-mix(in srgb, var(--c-csquare) 55%, transparent); transition: color .2s, border-color .2s; }
.co-link:hover { color: var(--c-csquare); border-bottom-color: var(--c-csquare); }
h3 .co-link { border-bottom: 0; }
.co-link .ext { font-size: .7em; color: var(--muted); vertical-align: .25em; }
.co-url { font-family: var(--mono); font-size: .82em; color: var(--c-csquare); text-decoration: none; }
.co-url:hover { text-decoration: underline; }
.card h3 { margin: 0; font-size: 1.32rem; font-weight: 800; letter-spacing: -.01em; line-height: 1.25; }
.card .role { margin: 2px 0 0; color: var(--muted); font-size: .92rem; }
.card .sum { margin: 0 0 16px; color: #d3d6ee; font-size: 1rem; line-height: 1.75; max-width: 68ch; }

/* project names as quiet chips: proof of depth without the jargon wall */
.tags { display: flex; flex-wrap: wrap; gap: 6px; margin: 0; padding: 0; list-style: none; }
.tags li { font-family: var(--mono); font-size: .74rem; line-height: 1; padding: 6px 10px; border-radius: 99px; color: #c3c7e6; background: rgba(255,255,255,.04); border: 1px solid rgba(255,255,255,.09); }

.projects { display: grid; gap: 8px; margin: 0; padding: 0; list-style: none; }
.projects li { padding: 10px 14px; border-radius: 10px; background: rgba(255,255,255,.03); border: 1px solid rgba(255,255,255,.05); }
.projects strong { display: block; font-size: .93rem; }
.projects strong em { font-style: normal; font-family: var(--mono); font-size: .7rem; color: var(--c); margin-left: 6px; padding: 1px 6px; border-radius: 4px; background: color-mix(in srgb, var(--c) 15%, transparent); }
.projects span { font-size: .86rem; color: var(--muted); }
.projects.compact { grid-template-columns: repeat(auto-fill, minmax(min(100%, 230px), 1fr)); }

.more { margin-top: 14px; border-top: 1px dashed rgba(255,255,255,.08); padding-top: 12px; }
.more summary { display: inline-flex; align-items: center; gap: 8px; cursor: pointer; list-style: none; font-size: .84rem; color: var(--muted); user-select: none; }
.more summary::-webkit-details-marker { display: none; }
.more summary::before { content: '+'; display: grid; place-items: center; width: 18px; height: 18px; border-radius: 5px; font-family: var(--mono); font-size: .8rem; border: 1px solid var(--line); transition: transform .2s; }
.more[open] summary::before { content: '−'; }
.more summary:hover { color: var(--text); }
.more .projects { margin-top: 12px; }

.badge { display: inline-block; margin-top: 14px; padding: 3px 11px; border-radius: 99px; font-size: .78rem; font-family: var(--mono); background: rgba(124,124,255,.12); color: #b9b9ff; border: 1px solid rgba(124,124,255,.35); text-decoration: none; }

@media (max-width: 760px) {
  .map { --axis-w: 28px; }
  .map::before { left: 13px; }
  .stop { grid-template-columns: var(--axis-w) 1fr; }
  .stop-date { grid-column: 2; grid-row: 1; text-align: left; flex-direction: row; flex-wrap: wrap; align-items: baseline; gap: 4px 10px; padding: 0 0 10px; }
  .stop-date b { font-size: 1.6rem; }
  .stop-node { grid-column: 1; grid-row: 1; }
  .stop-node::before { top: 8px; }
  .card { grid-column: 2; padding: 18px 16px; }
}

/* ---------- patents ---------- */
.patent-grid { display: grid; gap: 16px; grid-template-columns: repeat(auto-fill, minmax(min(100%, 310px), 1fr)); }
.patent {
  display: flex; flex-direction: column; gap: 6px; text-decoration: none;
  background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 20px;
  transition: transform .2s, border-color .2s;
}
.patent:hover { transform: translateY(-3px); border-color: var(--accent); }
.patent h3 { margin: 0; font-size: 1.02rem; line-height: 1.4; }
.patent .no { font-family: var(--mono); font-size: .78rem; color: var(--accent); }
.patent p { margin: 0; font-size: .88rem; color: var(--muted); }
.note { margin-top: 24px; font-size: .88rem; color: var(--muted); font-style: italic; }

/* ---------- education + contact ---------- */
.two { display: grid; gap: 20px; grid-template-columns: 1fr 1fr; }
@media (max-width: 760px) { .two { grid-template-columns: 1fr; } }
.panel { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 22px 24px; }
.panel h3 { margin: 0 0 6px; font-size: 1.1rem; }
.panel p { margin: 0; color: var(--muted); }
.panel a { color: var(--accent); }

footer { border-top: 1px solid var(--line); padding: 28px 0 40px; text-align: center; font-family: var(--mono); font-size: .8rem; color: var(--muted); }
footer a { color: var(--accent); text-decoration: none; margin: 0 8px; }

/* ---------- expertise ---------- */
.expertise { display: grid; gap: 16px; grid-template-columns: repeat(auto-fit, minmax(min(100%, 230px), 1fr)); }
.exp { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 22px; }
.exp-ico { font-family: var(--mono); font-size: .8rem; color: var(--accent); }
.exp h3 { margin: 8px 0 8px; font-size: 1.08rem; }
.exp p { margin: 0; font-size: .9rem; color: var(--muted); }
.principles { margin-top: 26px; padding: 20px 24px; border: 1px dashed var(--line); border-radius: var(--radius); }
.principles ul { margin: 0; padding: 0; list-style: none; display: grid; gap: 8px; }
.principles li { color: var(--muted); font-size: .95rem; }
.principles b { color: var(--text); font-weight: 600; margin-right: 6px; }

/* ---------- phones ---------- */
@media (max-width: 600px) {
  body { line-height: 1.6; }
  section { padding: 48px 0; }
  .sec-head { margin-bottom: 22px; }

  .topbar .wrap { height: 50px; }
  .lang button { padding: 6px 12px; }

  /* hero: photo next to the name instead of stacked on top */
  .hero { padding: 78px 0 44px; }
  .hero .wrap { grid-template-columns: 1fr auto; gap: 0 16px; align-items: start; }
  .hero .wrap > div { display: contents; }
  .hero .wrap > div > * { grid-column: 1 / -1; }
  .hero .wrap > div > .eyebrow { grid-column: 1; grid-row: 1; }
  .hero .wrap > div > h1 { grid-column: 1; grid-row: 2; min-width: 0; }
  .portrait { order: 0; grid-column: 2; grid-row: 1 / 3; align-self: center; width: 84px; height: 84px; border-width: 2px; box-shadow: 0 0 0 6px rgba(124,124,255,.12), 0 0 30px rgba(124,124,255,.3); }
  .eyebrow { margin-bottom: 8px; }
  .hero h1 { font-size: 2.6rem; }
  .hero h1 small { font-size: .95rem; margin-top: 8px; }
  .lead { font-size: 1rem; margin: 16px 0 22px; }
  .tagline { font-size: .8rem; margin-top: 14px; }
  .stats { display: grid; grid-template-columns: 1fr 1fr; gap: 8px; margin-bottom: 22px; }
  .stats li { min-width: 0; padding: 10px 14px; }
  .stats strong { font-size: 1.35rem; }
  .cta { display: grid; grid-template-columns: 1fr; gap: 8px; }
  .btn { text-align: center; padding: 12px 16px; }

  /* expertise: tighter cards */
  .expertise { gap: 10px; }
  .exp { padding: 16px 18px; }
  .exp h3 { margin: 4px 0 6px; font-size: 1rem; }
  .principles { padding: 16px 18px; }

  /* timeline */
  .stop { margin-bottom: 22px; }
  .card { padding: 16px 14px; }
  .card-head { gap: 12px; margin-bottom: 12px; }
  .logo { width: 88px; height: 40px; padding: 6px 9px; border-radius: 10px; }
  .logo.word { font-size: .84rem; }
  .logo.word small { font-size: .62rem; }
  .card h3 { font-size: 1.12rem; }
  .card .role { font-size: .85rem; }
  .card .sum { font-size: .94rem; line-height: 1.7; }
  .tags li { font-size: .7rem; padding: 5px 9px; }
  .projects li { padding: 9px 12px; }
  .card:hover { transform: none; }

  .patent { padding: 16px; }
  .panel { padding: 18px; }
  footer { padding: 22px 0 32px; font-size: .74rem; }
}
@media (max-width: 360px) {
  .hero h1 { font-size: 2.2rem; }
  .hero h1 small { font-size: .88rem; }
  .portrait { width: 68px; height: 68px; }
}

/* ---------- reveal ---------- */
.js .reveal { opacity: 0; transform: translateY(18px); transition: opacity .6s, transform .6s; }
.js .reveal.in { opacity: 1; transform: none; }
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .js .reveal { opacity: 1; transform: none; transition: none; }
  .stop.now .stop-node::before { animation: none; }
}