/* Chem-inspired light theme for KOC S3 Math dashboards (UI shell only) */

:root {
  --bg: #f8fafc;
  --panel: #ffffff;
  --panel2: #eef2f7;
  --ink: #1e293b;
  --dim: #64748b;
  --line: rgba(30, 41, 59, 0.12);
  --a: #4FC3F7;
  --accent: #4FC3F7;
  --on-accent: #ffffff;
  --nav-surface: rgba(255, 255, 255, 0.72);
  --shadow-soft: 0 4px 24px rgba(26, 31, 46, 0.06), 0 1px 2px rgba(26, 31, 46, 0.04);
}

/* ?�?� Topic page header (hidden in embed) ?�?� */
header {
  padding: 14px 28px;
  border-bottom: 1px solid var(--line);
  display: flex;
  align-items: center;
  gap: 14px;
  background: var(--nav-surface);
  backdrop-filter: blur(20px) saturate(180%);
  -webkit-backdrop-filter: blur(20px) saturate(180%);
}

html.in-embed header {
  display: none;
}

.topic-logo {
  height: 36px;
  width: auto;
  flex: none;
}

.topic-headings {
  display: flex;
  flex-direction: column;
  gap: 2px;
  min-width: 0;
}

.topic-brand {
  font-size: 13px;
  font-weight: 700;
  color: var(--dim);
  letter-spacing: -0.01em;
}

.topic-brand .plus {
  color: var(--a);
}

header h1 {
  font-size: 22px;
  margin: 0;
  font-weight: 700;
  letter-spacing: -0.02em;
}

header .crumb {
  color: var(--dim);
  font-size: 13px;
}

/* ?�?� Tabs (layout unchanged) ?�?� */
.tabs {
  display: flex;
  gap: 6px;
  padding: 14px 28px 0;
  flex-wrap: wrap;
  background: var(--bg);
  border-bottom: 1px solid var(--line);
}

html.in-embed .tabs {
  padding-top: 8px;
}

.tab {
  background: none;
  border: none;
  color: var(--dim);
  font: inherit;
  font-weight: 600;
  padding: 10px 16px;
  cursor: pointer;
  border-radius: 8px 8px 0 0;
  font-size: 15px;
  transition: color 0.15s, background 0.15s;
}

.tab:hover:not(.active) {
  color: var(--ink);
}

.tab.active {
  color: var(--ink);
  background: var(--panel);
  box-shadow: inset 0 -2px 0 var(--a);
}

.tab-row {
  display: flex;
  align-items: center;
  gap: 10px 14px;
  flex-wrap: wrap;
  padding: 10px 24px 0;
  flex: none;
  background: var(--bg);
  border-bottom: 1px solid var(--line);
}

html.in-embed .tab-row {
  padding-top: 6px;
}

.tab-row .tabs {
  padding: 0;
  border-bottom: none;
  flex: 1;
  min-width: 0;
}

/* iPad embed: All topics sits on the right of the tab row (hub viewer-bar hidden) */
.embed-back-btn {
  display: none;
}
html.tablet-touch.in-embed .tab-row {
  display: flex;
  align-items: center;
  gap: 10px 12px;
  flex-wrap: nowrap;
  padding: 6px 16px 0;
}
html.tablet-touch.in-embed .tab-row .tabs {
  flex-wrap: nowrap;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: none;
}
html.tablet-touch.in-embed .tab-row .tabs::-webkit-scrollbar {
  display: none;
}
html.tablet-touch.in-embed .tab {
  padding: 8px 12px;
  font-size: 14px;
  white-space: nowrap;
}
html.tablet-touch.in-embed .embed-back-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  flex: none;
  margin-left: auto;
  background: var(--panel, #fff);
  border: 1px solid var(--line, rgba(0, 0, 0, 0.08));
  color: var(--ink, #2c2420);
  font: inherit;
  font-weight: 600;
  font-size: 14px;
  padding: 8px 14px;
  border-radius: 999px;
  cursor: pointer;
  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.04);
  white-space: nowrap;
  touch-action: manipulation;
}
html.tablet-touch.in-embed .embed-back-btn:active {
  border-color: var(--a, #0277BD);
  color: var(--a, #0277BD);
}
html.tablet-touch.in-embed .panel {
  padding-top: 10px;
  padding-bottom: 12px;
}

/* ?�?� Subnav chips ?�?� */
.chip {
  background: var(--panel);
  border: 1px solid var(--line);
  color: var(--dim);
  font: inherit;
  font-weight: 600;
  padding: 8px 14px;
  border-radius: 999px;
  cursor: pointer;
  font-size: 14px;
  transition: all 0.15s;
  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.03);
}

.chip:hover {
  color: var(--ink);
  border-color: rgba(79, 195, 247, 0.35);
}

.chip.active {
  color: #fff;
  background: #4FC3F7;
  border-color: #4FC3F7;
}

/* JM29 accent ??must win when this sheet loads after paper-labs */
body.paper-labs .subnav .chip.active,
body.paper-labs .chip.active,
body.paper-labs .btn.active {
  color: #fff !important;
  background: #4FC3F7 !important;
  border-color: #4FC3F7 !important;
}