:root {
  --porcelain: #F7F8F6;
  --ink: #10202F;
  --slate: #51606E;
  --rule: #D3D9D8;
  --grid-blue: #1B4B8F;
  --signal: #F5C400;
  --critical: #D03B3B;
  --display: "Archivo", "Noto Sans KR", system-ui, sans-serif;
  --text: "Source Serif 4", "Noto Sans KR", Georgia, serif;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
  margin: 0; background: var(--porcelain); color: var(--ink);
  font-family: var(--text); font-size: 1.0938rem; line-height: 1.65;
  word-break: keep-all; overflow-wrap: break-word;
}
html[data-lang="ko"] body { font-family: "Noto Sans KR", system-ui, sans-serif; font-size: 1.0313rem; line-height: 1.8; }
html[data-lang="en"] [data-l="ko"],
html[data-lang="ko"] [data-l="en"] { display: none !important; }

a { color: var(--grid-blue); text-underline-offset: 0.18em; text-decoration-thickness: 1px; }
a:hover { text-decoration-thickness: 2px; }
:focus-visible { outline: 3px solid var(--signal); outline-offset: 3px; }
p { margin: 0 0 1em; max-width: 66ch; }
.wrap { max-width: 1080px; margin: 0 auto; padding: 0 32px; }

/* Top bar, stays in view while scrolling */
.top {
  display: flex; align-items: center; gap: 24px; padding: 20px 0;
  font-family: var(--display); font-size: 0.9375rem; border-bottom: 2px solid var(--ink);
  position: sticky; top: 0; z-index: 10; background: var(--porcelain);
}
.top .who { font-weight: 700; font-stretch: 110%; color: var(--ink); text-decoration: none; }
.top nav { display: flex; gap: 24px; margin-left: auto; }
.top nav a { color: var(--ink); text-decoration: none; }
.top nav a:hover { text-decoration: underline; }
.top nav a[aria-current="page"] { text-decoration: underline; text-decoration-color: var(--signal); text-decoration-thickness: 3px; text-underline-offset: 0.35em; }
.lang { display: flex; border: 2px solid var(--ink); flex: none; }
.lang button { font: inherit; font-weight: 600; color: var(--ink); background: transparent; border: 0; padding: 5px 12px; cursor: pointer; }
.lang button[aria-pressed="true"] { background: var(--ink); color: var(--porcelain); }

/* Home hero */
.hero { display: grid; grid-template-columns: minmax(0, 1fr) 210px; gap: 56px; align-items: start; padding: 64px 0 56px; }
.hero.no-photo { grid-template-columns: minmax(0, 1fr); }
.hero.no-photo .portrait { display: none; }
h1 { font-family: var(--display); font-weight: 800; font-stretch: 112%; font-size: clamp(2.6rem, 6vw, 4.25rem); line-height: 1.0; letter-spacing: -0.025em; margin: 0 0 18px; }
html[data-lang="ko"] h1 { letter-spacing: -0.03em; line-height: 1.15; }
.tagline { font-family: var(--display); font-weight: 600; font-size: clamp(1.2rem, 2.3vw, 1.5625rem); line-height: 1.3; margin: 0 0 24px; max-width: 26em; }
html[data-lang="ko"] .tagline { line-height: 1.5; }
.lede { font-size: 1.1875rem; line-height: 1.6; max-width: 36em; margin-bottom: 28px; }
html[data-lang="ko"] .lede { font-size: 1.0938rem; line-height: 1.85; }
.portrait { margin: 0; }
.portrait img { display: block; width: 100%; aspect-ratio: 4 / 5; object-fit: cover; border: 2px solid var(--ink); background: #E6EAE8; }

.links { display: flex; flex-wrap: wrap; gap: 12px; }
.links a { font-family: var(--display); font-weight: 600; font-size: 0.9688rem; color: var(--ink); text-decoration: none; border: 2px solid var(--ink); padding: 9px 18px; }
.links a.primary { background: var(--ink); color: var(--porcelain); }
.links a:hover { background: var(--signal); color: var(--ink); }
.links a[hidden] { display: none; }

.facts { margin: 0; display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 0 28px; background: var(--ink); color: var(--porcelain); padding: 6px 28px; }
.facts div { padding: 18px 0 20px; }
.facts dt { font-family: var(--display); font-size: 0.875rem; font-weight: 600; color: #AEBBC7; margin-bottom: 4px; }
.facts dd { margin: 0; font-family: var(--display); font-weight: 600; font-size: 1.0625rem; line-height: 1.4; }

/* Detail page heading */
.pagehead { padding: 56px 0 44px; border-bottom: 2px solid var(--ink); }
.pagehead .lede { margin-bottom: 0; }
.h1-page { font-size: clamp(1.9rem, 4.2vw, 3rem); line-height: 1.1; max-width: 22em; margin-bottom: 20px; }
html[data-lang="ko"] .h1-page { line-height: 1.3; }
.status { display: inline-block; background: var(--signal); font-family: var(--display); font-weight: 700; font-size: 0.8125rem; padding: 3px 10px; margin: 0 0 16px; }

/* Sections: title left, content right */
.section { display: grid; grid-template-columns: 220px minmax(0, 1fr); gap: 48px; padding: 52px 0; border-bottom: 1px solid var(--rule); scroll-margin-top: 84px; }
h2 { font-family: var(--display); font-weight: 750; font-stretch: 108%; font-size: 1.3125rem; line-height: 1.25; letter-spacing: -0.01em; margin: 0; }
.section > h2::before { content: ""; display: block; width: 32px; height: 6px; background: var(--signal); margin-bottom: 14px; }
h3 { font-family: var(--display); font-weight: 700; font-size: 1.0313rem; margin: 28px 0 8px; }
.section > div > h3:first-child, .cols2 h3, .skillgrid h3 { margin-top: 0; }
.kicker-title { font-family: var(--display); font-weight: 750; font-stretch: 105%; font-size: clamp(1.2rem, 2.1vw, 1.5rem); line-height: 1.28; max-width: 30em; margin-bottom: 14px; }
.feature .links, .section .links { margin-top: 20px; }
.note { color: var(--slate); font-size: 0.9688rem; border-left: 3px solid var(--rule); padding-left: 14px; }

ul.plain { margin: 0 0 1em; padding-left: 1.1em; max-width: 66ch; }
ul.plain li { margin-bottom: 0.5em; }
ul.lined, ul.tags { list-style: none; margin: 0; padding: 0; }
ul.lined li { padding: 7px 0; border-bottom: 1px solid var(--rule); font-size: 1rem; }
ul.tags { display: flex; flex-wrap: wrap; gap: 8px; }
ul.tags li { font-family: var(--display); font-weight: 600; font-size: 0.9375rem; border: 1.5px solid var(--ink); padding: 4px 12px; background: #fff; }

/* Rows */
.rows { border-top: 2px solid var(--ink); }
.row { display: grid; grid-template-columns: 190px minmax(0, 1fr); gap: 24px; padding: 18px 0; border-bottom: 1px solid var(--rule); }
.when { font-family: var(--display); font-size: 0.9375rem; color: var(--slate); }
.row .what { color: var(--slate); font-size: 0.9688rem; }
.row .what strong { font-family: var(--display); font-weight: 700; font-size: 1.0938rem; display: block; line-height: 1.35; color: var(--ink); }
.cols2 { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 36px; margin-top: 32px; }
.skillgrid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 36px 40px; }
.skillgrid > div { border-top: 2px solid var(--ink); padding-top: 16px; }
.skillgrid h3 { margin-bottom: 12px; }

/* Tables */
.scroll { overflow-x: auto; margin: 4px 0 14px; }
table { border-collapse: collapse; width: 100%; font-size: 0.9375rem; line-height: 1.45; font-family: var(--display); }
th, td { text-align: left; padding: 10px 14px 10px 0; border-bottom: 1px solid var(--rule); vertical-align: top; }
thead th { font-weight: 700; border-bottom: 2px solid var(--ink); white-space: nowrap; }
tbody th { font-weight: 700; white-space: nowrap; }
table.num td { font-variant-numeric: tabular-nums; white-space: nowrap; }
tr.hl th, tr.hl td { background: #FFF6CC; }
tr.hl th { padding-left: 8px; }
.v { display: inline-block; font-weight: 700; font-size: 0.8438rem; padding: 2px 7px; margin: 0 4px 2px 0; border: 1.5px solid var(--ink); white-space: nowrap; background: #fff; }
.v.no { background: var(--critical); border-color: var(--critical); color: #fff; }
table.verdicts td:has(.v) { white-space: nowrap; }
main > section:last-child { border-bottom: 0; }
.v.na { border-color: var(--rule); color: var(--slate); }
.legend { font-family: var(--display); font-size: 0.875rem; color: var(--slate); margin: 0 0 8px; max-width: none; }
.lg { display: inline-block; width: 11px; height: 11px; margin: 0 6px 0 0; vertical-align: -1px; }
.lg.ok { background: var(--grid-blue); border-radius: 50%; }
.lg.bad { background: var(--critical); transform: rotate(45deg) scale(.85); margin-left: 16px; }

/* Charts */
figure { margin: 28px 0 16px; }
figcaption { font-family: var(--display); font-weight: 700; font-size: 1.0625rem; margin-bottom: 6px; }
.chart { display: block; width: 100%; height: auto; background: #fff; border: 1px solid var(--rule); }
.chart .grid { stroke: #E7EBEA; stroke-width: 1; }
.chart .axis { stroke: #B9C2C0; stroke-width: 1; }
.chart .tick, .chart .axlab { font-family: var(--display); font-size: 12px; fill: var(--slate); }
.chart .series { fill: none; stroke: var(--grid-blue); stroke-width: 2; }
.chart .pt.ok { fill: var(--grid-blue); stroke: #fff; stroke-width: 2; }
.chart .pt.bad { fill: var(--critical); stroke: #fff; stroke-width: 2; }
.chart .limit { stroke: var(--critical); stroke-width: 1.5; stroke-dasharray: 6 4; }
.chart .buffer { stroke: var(--slate); stroke-width: 1.2; stroke-dasharray: 2 4; }
.chart .lim-lab { font-family: var(--display); font-size: 12px; font-weight: 600; fill: var(--ink); }
.chart .buffer-lab { font-weight: 400; fill: var(--slate); }
.chart .hit { fill: transparent; cursor: pointer; outline-offset: 0; }
#tip { position: fixed; z-index: 20; max-width: 280px; background: var(--ink); color: #fff; font-family: var(--display); font-size: 0.8438rem; line-height: 1.4; padding: 8px 10px; pointer-events: none; }
details.data { margin: 8px 0 8px; }
details.data summary { font-family: var(--display); font-weight: 600; font-size: 0.9375rem; cursor: pointer; color: var(--grid-blue); }

/* Beyond engineering: compact entries with a small photo */
.items { border-top: 2px solid var(--ink); }
.item { display: flex; gap: 32px; padding: 20px 0; border-bottom: 1px solid var(--rule); align-items: flex-start; }
.item img { width: 120px; height: 90px; object-fit: cover; border: 1.5px solid var(--ink); flex: none; }
.item h3 { margin: 2px 0 6px; font-size: 1.0938rem; }
.item p { font-size: 0.9688rem; color: var(--slate); margin: 0; }
.item .when { color: var(--slate); font-size: 0.875rem; }

/* Footer with contact */
footer { border-top: 2px solid var(--ink); margin-top: 8px; padding: 40px 0 48px; display: flex; justify-content: space-between; gap: 32px; flex-wrap: wrap; scroll-margin-top: 84px; }
footer h2 { margin-bottom: 14px; }
.mail { font-family: var(--display); font-weight: 750; font-stretch: 108%; font-size: clamp(1.2rem, 2.6vw, 1.75rem); letter-spacing: -0.015em; color: var(--ink); text-decoration-color: var(--signal); text-decoration-thickness: 4px; text-underline-offset: 0.2em; overflow-wrap: anywhere; }
.mail:hover { text-decoration-thickness: 6px; }
footer .links { margin-top: 20px; }
.fine { font-family: var(--display); font-size: 0.875rem; color: var(--slate); align-self: flex-end; margin: 0; }

@media (max-width: 900px) {
  .wrap { padding: 0 20px; }
  body { font-size: 1.0625rem; }
  .top { flex-wrap: wrap; gap: 10px 16px; padding: 12px 0; }
  .top nav { order: 3; width: 100%; margin-left: 0; gap: 18px; overflow-x: auto; white-space: nowrap; padding-bottom: 2px; font-size: 0.875rem; }
  .lang { margin-left: auto; }
  .hero { grid-template-columns: minmax(0, 1fr); gap: 28px; padding: 40px 0 36px; }
  .portrait { order: -1; max-width: 150px; }
  .facts { grid-template-columns: 1fr; padding: 4px 20px; }
  .facts div { padding: 14px 0; border-bottom: 1px solid rgba(255,255,255,.18); }
  .facts div:last-child { border-bottom: 0; }
  .pagehead { padding: 36px 0 32px; }
  .section { grid-template-columns: minmax(0, 1fr); gap: 18px; padding: 38px 0; scroll-margin-top: 110px; }
  .cols2, .skillgrid { grid-template-columns: minmax(0, 1fr); gap: 26px; }
  .row { grid-template-columns: 1fr; gap: 4px; }
  .item img { width: 88px; height: 66px; }
  footer { scroll-margin-top: 110px; }
}
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }

table.verdicts th, table.verdicts td { padding-right: 8px; }

/* Research roadmap */
.chip { display: inline-block; font-family: var(--display); font-weight: 700; font-size: 0.8125rem; line-height: 1.3; padding: 3px 10px; border: 1.5px solid var(--ink); margin: 0; vertical-align: 2px; }
.chip.done { background: var(--ink); color: var(--porcelain); }
.chip.next { background: var(--signal); }
.chip.planned { background: #fff; color: var(--slate); border-color: var(--slate); }
.chips { margin: 0 0 14px; display: flex; flex-wrap: wrap; gap: 8px; }
ol.stages { list-style: none; margin: 0 0 14px; padding: 0; border-top: 2px solid var(--ink); }
ol.stages li { display: grid; grid-template-columns: 44px minmax(0, 1fr); gap: 16px; padding: 18px 0; border-bottom: 1px solid var(--rule); }
ol.stages .n { font-family: var(--display); font-weight: 800; font-size: 1.25rem; width: 36px; height: 36px; display: grid; place-items: center; border: 2px solid var(--ink); }
ol.stages li.done .n { background: var(--ink); color: var(--porcelain); }
ol.stages li.next .n { background: var(--signal); }
ol.stages li.planned .n { border-color: var(--slate); color: var(--slate); }
ol.stages p { margin: 0 0 6px; font-size: 1rem; }
ol.stages .st-head { font-family: var(--display); font-size: 1.0938rem; }
ol.stages .st-head strong { margin-right: 6px; }
ol.stages a { font-family: var(--display); font-weight: 600; font-size: 0.9375rem; }
/* A stage is one framed block: header band, sections tagged with the stage number, end marker */
.stage { margin-top: 56px; border: 2px solid var(--ink); border-top: 0; background: #fff; scroll-margin-top: 84px; }
.stageband { display: grid; grid-template-columns: 72px minmax(0, 1fr); gap: 22px; align-items: start; background: var(--ink); color: var(--porcelain); padding: 28px 30px 26px; }
.stagenum { font-family: var(--display); font-weight: 800; font-size: 2.75rem; line-height: 1; width: 72px; height: 72px; display: grid; place-items: center; background: var(--signal); color: var(--ink); }
.stageband .chip.done { background: transparent; color: #AEBBC7; border: 0; padding: 0; margin-bottom: 6px; font-weight: 600; }
.stagetitle { font-family: var(--display); font-weight: 750; font-stretch: 105%; font-size: clamp(1.3rem, 2.6vw, 1.75rem); line-height: 1.25; margin: 0 0 16px; max-width: 30em; }
.jump { display: flex; flex-wrap: wrap; gap: 8px; }
.jump a { font-family: var(--display); font-weight: 600; font-size: 0.875rem; color: var(--porcelain); text-decoration: none; border: 1.5px solid rgba(255,255,255,.35); padding: 4px 10px; }
.jump a:hover { background: var(--signal); color: var(--ink); border-color: var(--signal); }
.stage .section { padding-left: 30px; padding-right: 30px; }
.stage .section > h2::before { content: "Stage " attr(data-stage-label); width: fit-content; height: auto; background: none; display: block; font-size: 0.75rem; font-weight: 700; color: var(--ink); background-color: var(--signal); padding: 2px 8px; margin-bottom: 12px; letter-spacing: 0; }
.stage .section:last-of-type { border-bottom: 1px solid var(--rule); }
.stageend { font-family: var(--display); font-size: 0.9375rem; color: var(--slate); margin: 0; padding: 18px 30px 22px; max-width: none; }
.stageend a { font-weight: 600; margin-left: 8px; }
.stage .section { scroll-margin-top: 84px; }
@media (max-width: 900px) {
  .stage { margin-top: 38px; scroll-margin-top: 110px; }
  .stageband { grid-template-columns: 1fr; gap: 14px; padding: 20px; }
  .stagenum { width: 52px; height: 52px; font-size: 2rem; }
  .stage .section { padding-left: 18px; padding-right: 18px; scroll-margin-top: 110px; }
  .stageend { padding: 16px 18px 20px; }
}

/* Other certifications: one quiet line */
.others { font-size: 0.9063rem; color: var(--slate); margin: 14px 0 0; max-width: none; }

/* Activity photos open full size; certificates are shown whole */
.item .thumb { flex: none; display: block; line-height: 0; }
.item img.doc { width: 210px; height: 311px; object-fit: cover; object-position: center top; }
.item .thumb:hover img { outline: 3px solid var(--signal); }

@media (max-width: 640px) { .item:has(img.doc) { flex-direction: column; gap: 16px; } .item img.doc { width: min(210px, 100%); height: auto; aspect-ratio: 210 / 311; } }