/* ─── Variables ─────────────────────────────────────────── */
:root {
  --bg:          #f7f8fa;
  --surface:     #ffffff;
  --border:      #e2e8f0;
  --border-dark: #cbd5e0;
  --text:        #1a202c;
  --text-muted:  #718096;
  --accent:      #2b6cb0;
  --accent-dim:  #ebf8ff;
  --accent-2:    #553c9a;
  --sat-text:    #276749;
  --sat-bg:      #f0fff4;
  --unsat-text:  #c53030;
  --unsat-bg:    #fff5f5;
  --shadow-sm:   0 1px 3px rgba(0,0,0,.07), 0 1px 2px rgba(0,0,0,.04);
  --shadow:      0 4px 6px rgba(0,0,0,.05), 0 1px 3px rgba(0,0,0,.06);
  --radius:      8px;
}

/* ─── Reset ─────────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

/* ─── Base ──────────────────────────────────────────────── */
body {
  font-family: system-ui, -apple-system, 'Segoe UI', sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  font-size: 15px;
}

a { color: var(--accent); }

/* ─── Header ────────────────────────────────────────────── */
header {
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: var(--shadow-sm);
}

.header-inner {
  max-width: 1140px;
  margin: 0 auto;
  padding: 1rem 1.5rem .75rem;
}

.header-top {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: .75rem;
}

h1 {
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--text);
  letter-spacing: -.01em;
}

.subtitle {
  color: var(--text-muted);
  font-size: .875rem;
  margin-top: .15rem;
}

.meta {
  font-size: .8rem;
  color: var(--text-muted);
  white-space: nowrap;
  padding-top: .2rem;
}

nav {
  display: flex;
  gap: 1.5rem;
  border-top: 1px solid var(--border);
  padding-top: .6rem;
}

nav a {
  font-size: .875rem;
  font-weight: 500;
  color: var(--text-muted);
  text-decoration: none;
  padding-bottom: .4rem;
  border-bottom: 2px solid transparent;
  transition: color .15s, border-color .15s;
}

nav a:hover {
  color: var(--accent);
  border-bottom-color: var(--accent);
}

/* ─── Main ──────────────────────────────────────────────── */
main {
  max-width: 1140px;
  margin: 0 auto;
  padding: 2.5rem 1.5rem 3rem;
}

/* ─── Sections ──────────────────────────────────────────── */
.section { margin-bottom: 3.5rem; }

.section-title {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 1.25rem;
  padding-bottom: .6rem;
  border-bottom: 2px solid var(--border);
  letter-spacing: -.01em;
}

.section-desc {
  font-size: .875rem;
  color: var(--text-muted);
  margin-top: -.75rem;
  margin-bottom: 1rem;
}

/* ─── Stats cards ───────────────────────────────────────── */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(210px, 1fr));
  gap: 1rem;
}

.stat-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-left: 4px solid var(--accent);
  border-radius: var(--radius);
  padding: 1.25rem 1.4rem;
  box-shadow: var(--shadow-sm);
}

.stat-card:nth-child(3) { border-left-color: #2c7a7b; }
.stat-card:nth-child(4) { border-left-color: var(--accent-2); }

.stat-label {
  font-size: .7rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: .06em;
  color: var(--text-muted);
}

.stat-value {
  font-size: 1.9rem;
  font-weight: 700;
  color: var(--text);
  line-height: 1.15;
  margin-top: .3rem;
  letter-spacing: -.02em;
}

.stat-sub {
  font-size: .8rem;
  color: var(--text-muted);
  margin-top: .25rem;
}

/* ─── Chart ─────────────────────────────────────────────── */
.chart-controls {
  margin-bottom: .75rem;
}

.toggle-label {
  display: inline-flex;
  align-items: center;
  gap: .4rem;
  font-size: .875rem;
  color: var(--text-muted);
  cursor: pointer;
  user-select: none;
}

.toggle-label input { cursor: pointer; }

.chart-wrapper {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
  box-shadow: var(--shadow-sm);
}

/* ─── Table controls ────────────────────────────────────── */
.table-controls {
  display: flex;
  gap: .75rem;
  margin-bottom: .9rem;
  flex-wrap: wrap;
}

.table-controls input,
.table-controls select {
  padding: .45rem .75rem;
  border: 1px solid var(--border-dark);
  border-radius: 6px;
  font-size: .875rem;
  background: var(--surface);
  color: var(--text);
  outline: none;
  transition: border-color .15s;
}

.table-controls input:focus,
.table-controls select:focus { border-color: var(--accent); }

.table-controls input { flex: 1; min-width: 180px; }

/* ─── Table ─────────────────────────────────────────────── */
.table-container {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
}

table {
  width: 100%;
  border-collapse: collapse;
  font-size: .875rem;
}

thead { background: #f9fafb; }

th {
  padding: .6rem 1rem;
  text-align: left;
  font-weight: 600;
  font-size: .72rem;
  text-transform: uppercase;
  letter-spacing: .05em;
  color: var(--text-muted);
  border-bottom: 1px solid var(--border);
  white-space: nowrap;
}

td {
  padding: .65rem 1rem;
  border-bottom: 1px solid var(--border);
  vertical-align: middle;
}

tbody tr:last-child td { border-bottom: none; }
tbody tr:hover { background: #f9fafb; }

.mono { font-family: 'SFMono-Regular', Consolas, 'Courier New', monospace; }

.badge {
  display: inline-block;
  padding: .15rem .55rem;
  border-radius: 20px;
  font-size: .72rem;
  font-weight: 700;
  letter-spacing: .03em;
}

.badge-sat     { background: var(--sat-bg);   color: var(--sat-text); }
.badge-unsat   { background: var(--unsat-bg); color: var(--unsat-text); }
.badge-unknown { background: #fffaf0;         color: #c05621; }

.diff-pos  { color: #c05621; }
.diff-neg  { color: var(--sat-text); }
.diff-zero { color: var(--text-muted); }

.btn-link {
  background: none;
  border: none;
  color: var(--accent);
  font-size: .8rem;
  cursor: pointer;
  padding: .2rem .4rem;
  border-radius: 4px;
  text-decoration: underline;
  white-space: nowrap;
}

.btn-link:hover { background: var(--accent-dim); }

.table-empty {
  text-align: center;
  color: var(--text-muted);
  padding: 2rem;
  font-size: .9rem;
}

.hidden { display: none; }

/* ─── Solutions ─────────────────────────────────────────── */
.accordion-controls {
  display: flex;
  align-items: center;
  gap: .5rem;
  margin-bottom: .75rem;
  font-size: .875rem;
}

.sep { color: var(--border-dark); }

.btn-text {
  background: none;
  border: none;
  color: var(--accent);
  cursor: pointer;
  font-size: .875rem;
  padding: 0;
  text-decoration: underline;
}

.btn-text:hover { color: #1a4e8a; }

.accordion {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  margin-bottom: .5rem;
  overflow: hidden;
  box-shadow: var(--shadow-sm);
}

.accordion-header {
  padding: .9rem 1.25rem;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  user-select: none;
  transition: background .12s;
}

.accordion-header:hover { background: #f9fafb; }

.accordion-title {
  font-weight: 600;
  font-size: .9rem;
}

.accordion-meta {
  font-size: .8rem;
  color: var(--text-muted);
  font-weight: 400;
}

.accordion-right {
  display: flex;
  align-items: center;
  gap: .75rem;
}

.accordion-icon {
  color: var(--text-muted);
  transition: transform .2s ease;
  flex-shrink: 0;
}

.accordion.open .accordion-icon { transform: rotate(180deg); }

.accordion-body {
  display: none;
  padding: 1rem 1.25rem 1.25rem;
  border-top: 1px solid var(--border);
}

.accordion.open .accordion-body { display: block; }

.solution-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(170px, 1fr));
  gap: .4rem;
}

.meeting-item {
  background: var(--accent-dim);
  border: 1px solid #bee3f8;
  border-radius: 6px;
  padding: .4rem .75rem;
  font-size: .825rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: .5rem;
}

.meeting-id { font-weight: 600; color: var(--accent); }
.meeting-slot { color: var(--text-muted); font-family: 'SFMono-Regular', Consolas, monospace; }

/* ─── Footer ────────────────────────────────────────────── */
footer {
  text-align: center;
  padding: 2rem 1.5rem;
  color: var(--text-muted);
  font-size: .825rem;
  border-top: 1px solid var(--border);
}

footer a { text-decoration: none; }
footer a:hover { text-decoration: underline; }

/* ─── Responsive ────────────────────────────────────────── */
@media (max-width: 720px) {
  .header-top { flex-direction: column; gap: .25rem; }
  .stats-grid { grid-template-columns: 1fr 1fr; }
  th:nth-child(2), td:nth-child(2),
  th:nth-child(3), td:nth-child(3),
  th:nth-child(4), td:nth-child(4) { display: none; }
}

@media (max-width: 480px) {
  .stats-grid { grid-template-columns: 1fr; }
  nav { gap: 1rem; }
  nav a { font-size: .8rem; }
}