/* ==========================================================================
   VENTRON — Design tokens
   Palette: near-black blueprint navy, steel grays, amber (light/optics),
   cyan (forming/CAE, blueprint line color)
   Type: Space Grotesk (technical/EN accents) + IBM Plex Sans KR (body/KR)
          + IBM Plex Mono (labels, coordinates, data)
   ========================================================================== */

@import url('https://fonts.googleapis.com/css2?family=Space+Grotesk:wght@400;500;600;700&family=IBM+Plex+Sans+KR:wght@400;500;600;700&family=IBM+Plex+Mono:wght@400;500&display=swap');

:root{
  --bg: #0a0f1a;
  --bg-panel: #10182a;
  --bg-panel-2: #141f36;
  --grid-line: rgba(79, 209, 232, 0.07);
  --grid-line-strong: rgba(79, 209, 232, 0.16);
  --border: #202c45;
  --text: #e7ecf3;
  --text-dim: #8a93a6;
  --text-faint: #57647a;
  --accent-amber: #f2b84b;
  --accent-amber-dim: rgba(242, 184, 75, 0.16);
  --accent-cyan: #4fd1e8;
  --accent-cyan-dim: rgba(79, 209, 232, 0.14);

  --font-display: 'Space Grotesk', sans-serif;
  --font-body: 'IBM Plex Sans KR', sans-serif;
  --font-mono: 'IBM Plex Mono', monospace;

  --maxw: 1180px;
}

*, *::before, *::after{ box-sizing: border-box; }
html{ scroll-behavior: smooth; }

body{
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  background-image:
    linear-gradient(var(--grid-line) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid-line) 1px, transparent 1px);
  background-size: 48px 48px;
}

@media (prefers-reduced-motion: reduce){
  *{ animation-duration: 0.01ms !important; animation-iteration-count: 1 !important; transition-duration: 0.01ms !important; scroll-behavior: auto !important; }
}

a{ color: inherit; text-decoration: none; }
img{ max-width: 100%; display:block; }

h1, h2, h3{
  font-family: var(--font-body);
  font-weight: 700;
  letter-spacing: -0.01em;
  margin: 0;
  color: #fff;
}

.eyebrow{
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--accent-cyan);
  display: flex;
  align-items: center;
  gap: 10px;
}
.eyebrow::before{
  content: '';
  width: 18px;
  height: 1px;
  background: var(--accent-cyan);
  display: inline-block;
}

.wrap{
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0 32px;
}

:focus-visible{
  outline: 2px solid var(--accent-cyan);
  outline-offset: 3px;
}

/* ---------- Header / Nav ---------- */
header.site{
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(10, 15, 26, 0.86);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
}
.nav{
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 20px 32px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.logo{
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 19px;
  letter-spacing: 0.02em;
  display: flex;
  align-items: center;
  gap: 10px;
}
.logo img.mark-icon{
  height: 32px;
  width: 32px;
  object-fit: contain;
  border-radius: 3px;
}
.logo .mark{
  color: var(--accent-amber);
  font-family: var(--font-mono);
  font-size: 13px;
}
footer .logo img.mark-icon{ height: 30px; width: 30px; }
.navlinks{
  display: flex;
  gap: 36px;
  font-size: 14.5px;
  color: var(--text-dim);
}
.navlinks a{
  position: relative;
  padding: 4px 0;
  transition: color 0.2s ease;
}
.navlinks a:hover{ color: var(--text); }
.navlinks a.active{ color: var(--text); }
.navlinks a.active::after{
  content: '';
  position: absolute;
  left: 0; right: 0; bottom: -6px;
  height: 2px;
  background: var(--accent-amber);
}
.navtoggle{ display:none; }

@media (max-width: 720px){
  .navlinks{
    position: fixed;
    inset: 65px 0 0 0;
    background: var(--bg);
    flex-direction: column;
    gap: 0;
    padding: 8px 32px 24px;
    display: none;
    border-bottom: 1px solid var(--border);
  }
  .navlinks.open{ display: flex; }
  .navlinks a{ padding: 14px 0; border-bottom: 1px solid var(--border); }
  .navtoggle{
    display: flex;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 6px;
  }
  .navtoggle span{ width: 22px; height: 2px; background: var(--text); }
}

/* ---------- Buttons ---------- */
.btn{
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: 13.5px;
  letter-spacing: 0.02em;
  padding: 13px 22px;
  border-radius: 3px;
  border: 1px solid var(--border);
  transition: border-color 0.2s ease, background 0.2s ease, transform 0.2s ease;
}
.btn-primary{
  background: var(--accent-amber);
  color: #171008;
  border-color: var(--accent-amber);
  font-weight: 500;
}
.btn-primary:hover{ transform: translateY(-1px); background: #ffc766; }
.btn-ghost{ color: var(--text); }
.btn-ghost:hover{ border-color: var(--accent-cyan); color: var(--accent-cyan); }
.btn-arrow{ transition: transform 0.2s ease; }
.btn:hover .btn-arrow{ transform: translateX(3px); }

/* ---------- Page header (non-home) ---------- */
.pagehead{
  padding: 76px 0 56px;
  border-bottom: 1px solid var(--border);
}
.pagehead h1{
  font-size: clamp(32px, 4.5vw, 46px);
  margin-top: 18px;
}
.pagehead p{
  color: var(--text-dim);
  max-width: 620px;
  margin-top: 16px;
  font-size: 16px;
}

section{ padding: 88px 0; }
section.tight{ padding: 56px 0; }
section + section{ border-top: 1px solid var(--border); }

/* ---------- Footer ---------- */
footer.site{
  border-top: 1px solid var(--border);
  padding: 44px 0;
  margin-top: 40px;
}
.footgrid{
  display: flex;
  justify-content: space-between;
  align-items: flex-end;
  flex-wrap: wrap;
  gap: 24px;
}
.footgrid .logo{ font-size: 16px; }
.footmeta{
  font-family: var(--font-mono);
  font-size: 12.5px;
  color: var(--text-faint);
  text-align: right;
  line-height: 1.9;
}
.footmeta a:hover{ color: var(--accent-cyan); }

/* ---------- Utility ---------- */
.grid-2{ display: grid; grid-template-columns: 1fr 1fr; gap: 56px; }
.grid-3{ display: grid; grid-template-columns: repeat(3, 1fr); gap: 28px; }
@media (max-width: 860px){
  .grid-2{ grid-template-columns: 1fr; gap: 40px; }
  .grid-3{ grid-template-columns: 1fr; }
}

.card{
  background: var(--bg-panel);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 32px;
}

.tag{
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-faint);
}

/* ---------- Insights / posts ---------- */
.postlist{
  display: flex;
  flex-direction: column;
  gap: 1px;
  background: var(--border);
  border: 1px solid var(--border);
  border-radius: 4px;
  overflow: hidden;
}
.postrow{
  background: var(--bg-panel);
  padding: 28px 32px;
  display: grid;
  grid-template-columns: 120px 1fr auto;
  gap: 24px;
  align-items: baseline;
  transition: background 0.2s ease;
}
.postrow:hover{ background: var(--bg-panel-2); }
.postrow .postdate{
  font-family: var(--font-mono);
  font-size: 12.5px;
  color: var(--text-faint);
}
.postrow .postmain h3{
  font-size: 17px;
  font-weight: 600;
  color: var(--text);
  margin-bottom: 6px;
}
.postrow .postmain p{
  font-size: 14px;
  color: var(--text-dim);
  margin: 0;
}
.postrow .postarrow{
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--accent-cyan);
  white-space: nowrap;
}
@media (max-width: 640px){
  .postrow{ grid-template-columns: 1fr; gap: 8px; }
  .postrow .postarrow{ display: none; }
}

/* article (single post) */
.article{
  max-width: 720px;
  margin: 0 auto;
}
.article .postmeta{
  font-family: var(--font-mono);
  font-size: 12.5px;
  color: var(--text-faint);
  margin-top: 18px;
}
.article h1{ font-size: clamp(28px, 4vw, 38px); line-height: 1.35; margin-top: 16px; }
.article .lead{ color: var(--text-dim); font-size: 16.5px; margin-top: 18px; }
.article .body{ margin-top: 44px; font-size: 15.5px; color: #d7dde6; }
.article .body h2{
  font-size: 21px;
  color: #fff;
  margin: 44px 0 16px;
  padding-top: 28px;
  border-top: 1px solid var(--border);
}
.article .body h2:first-child{ border-top: none; padding-top: 0; margin-top: 0; }
.article .body p{ margin: 0 0 18px; }
.article .body ul{ margin: 0 0 18px; padding-left: 20px; color: var(--text-dim); }
.article .body li{ margin-bottom: 8px; }
.article .body strong{ color: #fff; font-weight: 600; }
.article .backlink{
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--text-dim);
  margin-bottom: 8px;
}
.article .backlink:hover{ color: var(--accent-cyan); }