/* ---------- Design tokens ---------- */
:root {
  --bg: #0b0e13;
  --bg-elev: #12161d;
  --bg-elev-2: #171c25;
  --border: #262c37;
  --text: #e7eaef;
  --text-dim: #9aa4b2;
  --text-faint: #667085;
  --accent: #5ee0c0;
  --accent-dim: #2f6a5c;
  --tag-bg: #182a26;
  --tag-text: #7fe0c8;
  --radius: 10px;
  --maxw: 1040px;
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --mono: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
}

:root[data-theme="light"] {
  --bg: #f7f8fa;
  --bg-elev: #ffffff;
  --bg-elev-2: #f0f2f5;
  --border: #dde1e7;
  --text: #1a1d23;
  --text-dim: #4b5563;
  --text-faint: #8a94a3;
  --accent: #0f9d80;
  --accent-dim: #bfe9dd;
  --tag-bg: #e3f7f1;
  --tag-text: #0f9d80;
}

@media (prefers-color-scheme: light) {
  :root:not([data-theme="dark"]) {
    --bg: #f7f8fa;
    --bg-elev: #ffffff;
    --bg-elev-2: #f0f2f5;
    --border: #dde1e7;
    --text: #1a1d23;
    --text-dim: #4b5563;
    --text-faint: #8a94a3;
    --accent: #0f9d80;
    --accent-dim: #bfe9dd;
    --tag-bg: #e3f7f1;
    --tag-text: #0f9d80;
  }
}

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

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

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

img { max-width: 100%; display: block; }

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

/* ---------- Header ---------- */
header.site {
  position: sticky;
  top: 0;
  z-index: 20;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border);
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 0;
}

.nav .name {
  font-weight: 700;
  font-size: 1.05rem;
  letter-spacing: -0.01em;
  color: var(--text);
}

.nav .name span { color: var(--accent); }
.nav .name .role { font-weight: 500; color: var(--text-dim); }

.nav ul {
  list-style: none;
  display: flex;
  gap: 28px;
  margin: 0;
  padding: 0;
}

.nav ul a {
  color: var(--text-dim);
  font-size: 0.92rem;
  font-weight: 500;
}

.nav ul a:hover { color: var(--text); text-decoration: none; }

.theme-toggle {
  background: var(--bg-elev-2);
  border: 1px solid var(--border);
  color: var(--text-dim);
  border-radius: 8px;
  padding: 6px 10px;
  cursor: pointer;
  font-size: 0.85rem;
}

/* ---------- Hero ---------- */
.hero {
  padding: 72px 0 56px;
  border-bottom: 1px solid var(--border);
}

.eyebrow {
  font-family: var(--mono);
  color: var(--accent);
  font-size: 0.85rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  margin-bottom: 14px;
}

.hero h1 {
  font-size: clamp(1.9rem, 4vw, 2.7rem);
  line-height: 1.15;
  margin: 0 0 18px;
  letter-spacing: -0.01em;
}

.hero p.lead {
  color: var(--text-dim);
  font-size: 1.05rem;
  max-width: 640px;
  margin: 0 0 28px;
}

.hero .actions {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 18px;
  border-radius: 8px;
  font-size: 0.92rem;
  font-weight: 600;
  border: 1px solid var(--border);
  color: var(--text);
  background: var(--bg-elev);
}

.btn:hover { text-decoration: none; border-color: var(--accent-dim); }

.btn.primary {
  background: var(--accent);
  border-color: var(--accent);
  color: #0b0e13;
}

.btn.primary:hover { filter: brightness(1.08); }

/* ---------- Sections ---------- */
section { padding: 56px 0; border-bottom: 1px solid var(--border); }
section:last-of-type { border-bottom: none; }

.section-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  margin-bottom: 28px;
  gap: 16px;
  flex-wrap: wrap;
}

.section-head h2 {
  font-size: 1.4rem;
  margin: 0;
}

.section-head .num {
  font-family: var(--mono);
  color: var(--text-faint);
  font-size: 0.85rem;
}

.about-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 24px;
  color: var(--text-dim);
  max-width: 720px;
}

.skills {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 20px;
}

.skills span {
  font-family: var(--mono);
  font-size: 0.82rem;
  background: var(--bg-elev-2);
  border: 1px solid var(--border);
  color: var(--text-dim);
  padding: 5px 10px;
  border-radius: 6px;
}

/* ---------- Project cards ---------- */
.projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 22px;
}

.card {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  display: flex;
  flex-direction: column;
  transition: border-color 0.15s ease, transform 0.15s ease;
}

.card:hover {
  border-color: var(--accent-dim);
  transform: translateY(-2px);
}

.card .thumb {
  aspect-ratio: 16 / 10;
  background: var(--bg-elev-2);
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
}

.card .thumb img { width: 100%; height: 100%; object-fit: cover; }

.card .body { padding: 18px 20px 22px; display: flex; flex-direction: column; gap: 10px; flex: 1; }

.card h3 { margin: 0; font-size: 1.08rem; }

.card p { margin: 0; color: var(--text-dim); font-size: 0.92rem; flex: 1; }

.card .tags { display: flex; flex-wrap: wrap; gap: 6px; }

.card .tags span {
  font-family: var(--mono);
  font-size: 0.72rem;
  background: var(--tag-bg);
  color: var(--tag-text);
  padding: 3px 8px;
  border-radius: 5px;
}

.card .link-row {
  margin-top: 4px;
  font-size: 0.88rem;
  font-weight: 600;
}

.card.placeholder {
  border-style: dashed;
  align-items: center;
  justify-content: center;
  text-align: center;
  color: var(--text-faint);
  min-height: 220px;
  padding: 20px;
}

.card.placeholder .body { justify-content: center; align-items: center; }

/* ---------- Contact ---------- */
.contact-links {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  margin-top: 8px;
}

.contact-links a {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 16px;
  border: 1px solid var(--border);
  border-radius: 8px;
  color: var(--text);
  font-size: 0.92rem;
  background: var(--bg-elev);
}

.contact-links a:hover { text-decoration: none; border-color: var(--accent-dim); }

footer.site {
  padding: 28px 0 40px;
  color: var(--text-faint);
  font-size: 0.82rem;
}

/* ---------- Project detail page ---------- */
.breadcrumb {
  padding: 20px 0 0;
  font-size: 0.85rem;
  color: var(--text-faint);
}

.project-hero { padding: 24px 0 40px; border-bottom: 1px solid var(--border); }

.project-hero h1 { font-size: clamp(1.7rem, 3.4vw, 2.3rem); margin: 6px 0 14px; }

.project-hero .tags { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 18px; }

.project-hero .tags span {
  font-family: var(--mono);
  font-size: 0.78rem;
  background: var(--tag-bg);
  color: var(--tag-text);
  padding: 4px 10px;
  border-radius: 6px;
}

.gallery {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  margin: 24px 0;
}

.gallery img {
  border-radius: var(--radius);
  border: 1px solid var(--border);
  width: 100%;
}

.spec-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9rem;
  margin: 12px 0 0;
}

.spec-table td {
  padding: 9px 0;
  border-bottom: 1px solid var(--border);
  vertical-align: top;
}

.spec-table td:first-child {
  color: var(--text-faint);
  font-family: var(--mono);
  font-size: 0.82rem;
  width: 190px;
  white-space: nowrap;
}

.prose { color: var(--text-dim); max-width: 720px; }
.prose ul { padding-left: 20px; }
.prose li { margin-bottom: 8px; }

/* ---------- KiCanvas viewer ---------- */
.viewer-tabs {
  display: flex;
  gap: 4px;
  border: 1px solid var(--border);
  background: var(--bg-elev-2);
  border-radius: 8px 8px 0 0;
  padding: 6px;
}

.viewer-tabs button {
  font-family: var(--mono);
  font-size: 0.82rem;
  background: transparent;
  border: none;
  color: var(--text-dim);
  padding: 8px 14px;
  border-radius: 6px;
  cursor: pointer;
}

.viewer-tabs button.active {
  background: var(--bg-elev);
  color: var(--accent);
}

.viewer-frame {
  border: 1px solid var(--border);
  border-top: none;
  border-radius: 0 0 var(--radius) var(--radius);
  overflow: hidden;
  background: #131316;
  height: 640px;
}

.viewer-panel { display: none; width: 100%; height: 100%; }
.viewer-panel.active { display: block; }

kicanvas-embed { width: 100%; height: 100%; display: block; }

.viewer-note {
  font-size: 0.82rem;
  color: var(--text-faint);
  margin-top: 10px;
}

.downloads {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 16px;
}

@media (max-width: 640px) {
  .nav ul { gap: 16px; }
  .nav .name span, .nav .name .role { display: none; }
  .nav ul li:nth-child(n+4) { display: none; }
  .gallery { grid-template-columns: 1fr; }
  .viewer-frame { height: 460px; }
  .spec-table td:first-child { width: 130px; }
}

/* ---------- Project video ---------- */
.video-frame {
  margin: 24px 0 0;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  background: #ffffff;
}

.video-frame video { display: block; width: 100%; height: auto; }
.video-frame.narrow { max-width: 480px; }

.card .thumb video { width: 100%; height: 100%; object-fit: cover; }

.video-frame img { display: block; width: 100%; height: auto; }

/* ---------- Diagrams, formulas, code excerpts ---------- */
.prose h3 { color: var(--text); font-size: 1.02rem; margin: 28px 0 8px; }

.diagram {
  margin: 20px 0 24px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--bg-elev);
  padding: 16px;
  max-width: 720px;
}
.diagram svg { display: block; width: 100%; height: auto; }
.diagram img { width: 100%; height: auto; border-radius: 6px; }
/* two screenshots in one figure; set --cols to their aspect ratios so both get the same height */
.diagram .pair { display: grid; grid-template-columns: var(--cols, 1fr 1fr); gap: 12px; }
@media (max-width: 640px) { .diagram .pair { grid-template-columns: 1fr; } }
.diagram figcaption { font-size: 0.82rem; color: var(--text-faint); margin-top: 10px; }
.diagram .ln { stroke: var(--text-dim); stroke-width: 1.5; fill: none; }
.diagram .dash { stroke: var(--text-faint); stroke-width: 1; stroke-dasharray: 4 4; fill: none; }
.diagram .acc { stroke: var(--accent); stroke-width: 2; fill: none; }
.diagram .body { fill: var(--bg-elev-2); stroke: var(--text-dim); stroke-width: 1.5; }
.diagram .wheel { fill: var(--text-dim); }
.diagram .wheel.steer { fill: var(--accent); }
.diagram .box { fill: var(--bg-elev-2); stroke: var(--border); stroke-width: 1.5; }
.diagram .box.hl { stroke: var(--accent); }
.diagram .dot { fill: var(--accent); }
.diagram text { fill: var(--text); font-family: var(--font); font-size: 13px; }
.diagram text.dim { fill: var(--text-dim); font-size: 11.5px; }
.diagram text.mono { font-family: var(--mono); font-size: 11.5px; fill: var(--accent); }
.diagram .arrowhead { fill: var(--text-dim); }

.formula {
  font-family: var(--mono);
  font-size: 0.88rem;
  color: var(--text);
  background: var(--bg-elev-2);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 12px 16px;
  margin: 12px 0;
  line-height: 1.8;
  overflow-x: auto;
  white-space: nowrap;
}

pre.code {
  font-family: var(--mono);
  font-size: 0.8rem;
  line-height: 1.55;
  color: var(--text);
  background: var(--bg-elev-2);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 14px 16px;
  margin: 12px 0 6px;
  overflow-x: auto;
  max-width: 720px;
}
pre.code .c { color: var(--text-faint); }
.code-src { font-size: 0.78rem; color: var(--text-faint); margin: 0 0 16px; }