/* ── Design tokens ── */
:root {
  --bg: #f6f8fb;
  --card: #ffffff;
  --accent: #0b76ef;
  --accent-hover: #0860c5;
  --text: #0b2136;
  --muted: #6b7a8a;
  --border: #e0e8f0;
  --tag-bg: #eef2f7;
  --badge-bg: #e8f0fe;
  --badge-color: #1a56db;
  --section-line: #0b76ef;
  --child-header-bg: #f4f7fb;
  --child-row-border: #edf1f7;
  --thumb-placeholder-bg: #e8edf5;
  --radius: 10px;
  --shadow: 0 4px 18px rgba(11, 33, 54, 0.08);
}

/* ── Reset ── */
*, *::before, *::after { box-sizing: border-box; }

/* ── Base ── */
body {
  margin: 0;
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background: linear-gradient(160deg, var(--bg) 0%, #e9eef6 100%);
  color: var(--text);
  padding: 1.5rem 1rem 3rem;
  min-height: 100vh;
}

.wrap {
  max-width: 900px;
  margin: 0 auto;
}

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

/* ── Header ── */
header { margin-bottom: 1.75rem; }
header h1 { margin: 0 0 .3rem; font-size: 1.6rem; font-weight: 700; }
.lead { margin: 0 0 1rem; color: var(--muted); font-size: .95rem; }

/* ── View-mode nav ── */
.view-nav {
  display: flex;
  gap: .5rem;
  flex-wrap: wrap;
}
.view-btn {
  display: inline-flex;
  align-items: center;
  gap: .3rem;
  padding: .4rem 1rem;
  border-radius: 6px;
  font-size: .875rem;
  font-weight: 500;
  cursor: pointer;
  border: 2px solid var(--accent);
  background: var(--accent);
  color: #fff;
  text-decoration: none;
  transition: background .15s, color .15s;
}
.view-btn:not(.active):not([disabled]):hover {
  background: var(--accent-hover);
  border-color: var(--accent-hover);
  text-decoration: none;
}
.view-btn.active,
.view-btn[disabled] {
  background: #fff;
  color: var(--accent);
  cursor: default;
}
.view-btn.active:hover { text-decoration: none; }

/* ── Category section ── */
.category-section { margin-bottom: 2.75rem; }
.category-title {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text);
  border-bottom: 3px solid var(--section-line);
  padding-bottom: .45rem;
  margin: 0 0 1.25rem;
}
.cert-list { display: flex; flex-direction: column; gap: 1.25rem; }

/* ── Parent cert card ── */
.parent-cert {
  background: var(--card);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  overflow: hidden;
  border: 1px solid var(--border);
}
.cert-card {
  display: flex;
  gap: 1rem;
  padding: 1rem 1.25rem;
  align-items: flex-start;
}

/* Thumbnail */
.cert-thumbnail {
  flex: 0 0 76px;
  width: 76px;
  height: 76px;
  border-radius: 8px;
  overflow: hidden;
  background: var(--thumb-placeholder-bg);
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
}
.cert-thumbnail img {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
  z-index: 1;
  border-radius: inherit;
}
.thumb-placeholder {
  font-size: 2rem;
  line-height: 1;
  user-select: none;
}

/* Cert body */
.cert-body { flex: 1; min-width: 0; }

.cert-type-badge {
  display: inline-block;
  background: var(--badge-bg);
  color: var(--badge-color);
  font-size: .72rem;
  font-weight: 600;
  padding: .15rem .55rem;
  border-radius: 4px;
  margin-bottom: .4rem;
  letter-spacing: .01em;
}
.cert-role-badge {
  display: inline-block;
  background: #e6f4ea;
  color: #1e7e34;
  font-size: .72rem;
  font-weight: 700;
  padding: .15rem .55rem;
  border-radius: 4px;
  margin-bottom: .4rem;
  margin-right: .35rem;
  letter-spacing: .03em;
  text-transform: uppercase;
}
.cert-title {
  margin: 0 0 .3rem;
  font-size: 1rem;
  font-weight: 700;
  line-height: 1.35;
}
.cert-issuer {
  color: var(--muted);
  font-size: .875rem;
  margin-bottom: .4rem;
}

/* Tags */
.cert-tags {
  display: flex;
  flex-wrap: wrap;
  gap: .25rem;
  margin-bottom: .55rem;
}
.tag {
  display: inline-block;
  background: var(--tag-bg);
  color: #445;
  font-size: .72rem;
  padding: .1rem .45rem;
  border-radius: 20px;
  letter-spacing: .01em;
}

/* Meta row */
.cert-meta {
  display: flex;
  flex-wrap: wrap;
  gap: .6rem;
  align-items: center;
  font-size: .825rem;
  color: var(--muted);
}
.cert-date { white-space: nowrap; }
.cert-id {
  font-family: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
  font-size: .78rem;
  color: var(--muted);
}

/* Verify button */
.verify-btn {
  display: inline-block;
  background: var(--accent);
  color: #fff !important;
  padding: .28rem .8rem;
  border-radius: 5px;
  font-size: .8rem;
  font-weight: 500;
  text-decoration: none !important;
  transition: background .15s;
  white-space: nowrap;
}
.verify-btn:hover { background: var(--accent-hover); }
.verify-btn--sm {
  padding: .2rem .6rem;
  font-size: .75rem;
}

/* ── Children section ── */
.children-section { border-top: 1px solid var(--border); }

.children-header {
  background: var(--child-header-bg);
  padding: .55rem 1.25rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: .5rem;
}
.children-label {
  font-size: .78rem;
  font-weight: 600;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: .04em;
}
.toggle-btn {
  background: var(--accent);
  color: #fff;
  border: none;
  border-radius: 5px;
  padding: .3rem .85rem;
  cursor: pointer;
  font-size: .8rem;
  font-weight: 500;
  transition: background .15s;
  white-space: nowrap;
}
.toggle-btn:hover { background: var(--accent-hover); }

/* Children table */
.children-table {
  width: 100%;
  border-collapse: collapse;
  font-size: .875rem;
}
.children-table th {
  background: #f0f4fa;
  padding: .5rem .75rem;
  text-align: left;
  font-size: .78rem;
  font-weight: 700;
  color: var(--text);
  border-bottom: 2px solid var(--border);
  white-space: nowrap;
}
.children-table td {
  padding: .55rem .75rem;
  border-bottom: 1px solid var(--child-row-border);
  vertical-align: middle;
}
.children-table tbody tr:last-child td { border-bottom: none; }
.children-table tbody tr:hover { background: #fafcff; }

.col-num {
  width: 2.5rem;
  text-align: center;
  color: var(--muted);
  font-size: .8rem;
}
.col-date { white-space: nowrap; color: var(--muted); font-size: .82rem; }
.col-id {
  font-family: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
  font-size: .78rem;
  color: var(--muted);
  white-space: nowrap;
}
.child-title { font-weight: 600; line-height: 1.3; }
.child-type { color: var(--muted); font-size: .76rem; margin-top: .1rem; }

/* ── Utility ── */
.muted { color: var(--muted); font-size: .95rem; }
.center { text-align: center; }

/* ── Footer ── */
footer {
  margin-top: 2rem;
  color: var(--muted);
  font-size: .85rem;
  text-align: center;
}

/* ── Thumbnail gallery grid (used by gallery.html) ── */
.thumb-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
  gap: 10px;
}
.thumb-card {
  background: var(--card);
  padding: 6px;
  border-radius: 8px;
  box-shadow: 0 2px 8px rgba(11, 33, 54, 0.06);
}
.thumb-card img {
  width: 100%;
  height: auto;
  display: block;
  border-radius: 4px;
}

/* ── Responsive ── */
@media (max-width: 640px) {
  body { padding: 1rem .75rem 2.5rem; }
  .cert-card { flex-direction: column; }
  .cert-thumbnail { width: 60px; height: 60px; flex: none; }
  .cert-meta { gap: .4rem; }

  /* hide credential ID column in children table on narrow screens */
  .children-table .col-id,
  .children-table th.col-id { display: none; }
}

@media (max-width: 420px) {
  /* hide date column as well on very narrow screens */
  .children-table .col-date,
  .children-table th.col-date { display: none; }
}