/* Reference — field-guide archive UI */

:root,
[data-theme="light"] {
  --bg: #e6eaf0;
  --bg-accent: #c9d6e8;
  --surface: #f7f8fb;
  --surface-2: #eef1f6;
  --border: #c5cedb;
  --text: #121826;
  --muted: #5a6578;
  --accent: #0b6e6a;
  --accent-hover: #085954;
  --accent-soft: color-mix(in srgb, var(--accent) 14%, transparent);
  --accent-ink: #0a5c58;
  --mark: #b45309;
  --mark-soft: rgba(180, 83, 9, 0.12);
  --danger: #b91c1c;
  --radius: 10px;
  --shadow: 0 10px 28px rgba(18, 24, 38, 0.08);
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
  --font-body: "IBM Plex Sans", system-ui, sans-serif;
  --font-display: "Literata", Georgia, "Times New Roman", serif;
  --font-mono: "IBM Plex Mono", ui-monospace, monospace;
}

[data-theme="dark"] {
  --bg: #0e141c;
  --bg-accent: #1a2838;
  --surface: #161e29;
  --surface-2: #1d2735;
  --border: #2e3b4d;
  --text: #e8eef7;
  --muted: #93a0b4;
  --accent: #2dd4bf;
  --accent-hover: #5eead4;
  --accent-soft: color-mix(in srgb, var(--accent) 16%, transparent);
  --accent-ink: #99f6e4;
  --mark: #fbbf24;
  --mark-soft: rgba(251, 191, 36, 0.14);
  --danger: #f87171;
  --shadow: 0 10px 28px rgba(0, 0, 0, 0.35);
}

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

html {
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  min-height: 100dvh;
  font-family: var(--font-body);
  font-size: 1rem;
  line-height: 1.55;
  color: var(--text);
  background:
    radial-gradient(ellipse 80% 50% at 100% -10%, color-mix(in srgb, var(--accent) 18%, transparent), transparent 55%),
    radial-gradient(ellipse 60% 40% at 0% 100%, color-mix(in srgb, var(--mark) 10%, transparent), transparent 50%),
    linear-gradient(165deg, var(--bg-accent) 0%, var(--bg) 48%, var(--bg) 100%);
  background-attachment: fixed;
  -webkit-font-smoothing: antialiased;
}

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

.shell {
  width: min(1120px, calc(100% - 2rem));
  margin: 0 auto;
  padding: 1.25rem 0 3.5rem;
}

.site-header {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-start;
  justify-content: space-between;
  gap: 0.75rem 1.25rem;
  margin-bottom: 1rem;
}

.brand {
  display: flex;
  gap: 0.75rem;
  align-items: flex-start;
  text-decoration: none;
  color: inherit;
}

.brand-mark {
  flex-shrink: 0;
  color: var(--accent);
  margin-top: 0.15rem;
}

.brand-name {
  margin: 0;
  font-family: var(--font-display);
  font-size: clamp(1.45rem, 2.5vw, 1.85rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1.15;
}

.brand-tagline {
  margin: 0.2rem 0 0;
  color: var(--muted);
  font-size: 0.92rem;
}

.header-actions {
  display: flex;
  gap: 0.5rem;
  align-items: center;
}

.theme-toggle {
  appearance: none;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text);
  border-radius: 999px;
  padding: 0.4rem 0.85rem;
  font: inherit;
  font-size: 0.85rem;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.2s var(--ease), border-color 0.2s var(--ease);
}

.theme-toggle:hover {
  border-color: var(--accent);
  background: var(--accent-soft);
}

.app-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 0.3rem;
  margin: 0 0 1.25rem;
  padding: 0;
  max-height: 9.5rem;
  overflow-y: auto;
}

.app-nav-link {
  display: inline-flex;
  align-items: center;
  padding: 0.28rem 0.55rem;
  border-radius: 999px;
  border: 1px solid transparent;
  text-decoration: none;
  color: var(--muted);
  font-size: 0.75rem;
  font-weight: 600;
  transition: color 0.15s var(--ease), background 0.15s var(--ease), border-color 0.15s var(--ease);
}

.app-nav-link:hover {
  color: var(--text);
  background: var(--surface);
  border-color: var(--border);
}

.app-nav-link.is-active {
  color: var(--accent-ink);
  background: var(--accent-soft);
  border-color: color-mix(in srgb, var(--accent) 35%, var(--border));
}

.hub-hero {
  margin: 0.5rem 0 1.75rem;
}

.hub-hero .eyebrow {
  margin: 0 0 0.4rem;
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--accent-ink);
}

.hub-hero h1 {
  margin: 0 0 0.65rem;
  font-family: var(--font-display);
  font-size: clamp(1.85rem, 4.2vw, 2.65rem);
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1.15;
  max-width: 18ch;
}

.hub-hero .lede {
  margin: 0;
  max-width: 42rem;
  color: var(--muted);
  font-size: 1.05rem;
}

.app-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 0.85rem;
}

.app-card {
  display: flex;
  flex-direction: column;
  gap: 0.45rem;
  padding: 1.1rem 1.15rem 1.15rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  text-decoration: none;
  color: inherit;
  box-shadow: var(--shadow);
  transition: transform 0.2s var(--ease), border-color 0.2s var(--ease), box-shadow 0.2s var(--ease);
}

.app-card:hover {
  transform: translateY(-2px);
  border-color: color-mix(in srgb, var(--accent) 45%, var(--border));
  box-shadow: 0 14px 32px rgba(18, 24, 38, 0.12);
}

.app-card .domain {
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--accent-ink);
}

.app-card h2 {
  margin: 0;
  font-family: var(--font-display);
  font-size: 1.2rem;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.app-card p {
  margin: 0;
  flex: 1;
  color: var(--muted);
  font-size: 0.9rem;
}

.app-card .go {
  margin-top: 0.35rem;
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--accent-ink);
}

.category-section {
  margin: 0 0 0.5rem;
}

.category-section-title {
  margin: 0 0 0.25rem;
  font-family: var(--font-display);
  font-size: 1.2rem;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.category-section-lede {
  margin: 0 0 0.75rem;
  color: var(--muted);
  font-size: 0.9rem;
}

.category-dir {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 0.65rem;
  margin: 0 0 1.1rem;
}

.category-card {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
  text-align: left;
  padding: 0.85rem 0.95rem;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--surface);
  color: inherit;
  font: inherit;
  cursor: pointer;
  box-shadow: var(--shadow);
  transition: border-color 0.15s var(--ease), background 0.15s var(--ease), transform 0.15s var(--ease);
}

.category-card:hover,
.category-card.is-active {
  border-color: color-mix(in srgb, var(--accent) 45%, var(--border));
  background: var(--accent-soft);
  transform: translateY(-1px);
}

.category-card-name {
  font-family: var(--font-display);
  font-size: 1.05rem;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.category-card-blurb {
  color: var(--muted);
  font-size: 0.86rem;
  line-height: 1.4;
}

.category-card-count {
  margin-top: 0.15rem;
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--accent-ink);
}

.page-help {
  margin: 0 0 1rem;
  padding: 0.65rem 0.9rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
}

.page-help summary {
  cursor: pointer;
  font-weight: 650;
  font-size: 0.92rem;
}

.page-help-body {
  margin-top: 0.55rem;
  color: var(--muted);
  font-size: 0.9rem;
}

.page-help-body ul {
  margin: 0.4rem 0 0;
  padding-left: 1.15rem;
}

.ref-controls {
  display: grid;
  gap: 0.75rem;
  margin-bottom: 0.85rem;
}

.search-field {
  position: relative;
  display: block;
}

.search-icon {
  position: absolute;
  left: 0.85rem;
  top: 50%;
  transform: translateY(-50%);
  color: var(--muted);
  pointer-events: none;
}

.search-input {
  width: 100%;
  padding: 0.7rem 0.9rem 0.7rem 2.55rem;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--surface);
  color: var(--text);
  font: inherit;
  font-size: 0.98rem;
  outline: none;
  transition: border-color 0.15s var(--ease), box-shadow 0.15s var(--ease);
}

.search-input:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-soft);
}

.filter-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
  align-items: center;
}

.chip,
.filter-select {
  appearance: none;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text);
  border-radius: 999px;
  padding: 0.35rem 0.75rem;
  font: inherit;
  font-size: 0.8rem;
  font-weight: 600;
  cursor: pointer;
}

.chip.is-active {
  background: var(--accent-soft);
  border-color: color-mix(in srgb, var(--accent) 40%, var(--border));
  color: var(--accent-ink);
}

.filter-select {
  padding-right: 1.6rem;
  background-image: linear-gradient(45deg, transparent 50%, var(--muted) 50%),
    linear-gradient(135deg, var(--muted) 50%, transparent 50%);
  background-position: calc(100% - 14px) 55%, calc(100% - 9px) 55%;
  background-size: 5px 5px, 5px 5px;
  background-repeat: no-repeat;
}

.ref-summary {
  margin: 0 0 0.75rem;
  color: var(--muted);
  font-size: 0.88rem;
}

.ref-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1.15fr);
  gap: 0.85rem;
  min-height: 420px;
}

@media (max-width: 820px) {
  .ref-layout {
    grid-template-columns: 1fr;
  }
}

.ref-list,
.ref-detail {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  overflow: hidden;
}

.ref-list {
  max-height: min(70vh, 640px);
  overflow: auto;
}

.ref-list-item {
  display: block;
  width: 100%;
  text-align: left;
  border: 0;
  border-bottom: 1px solid var(--border);
  background: transparent;
  color: inherit;
  padding: 0.75rem 0.9rem;
  font: inherit;
  cursor: pointer;
  transition: background 0.12s var(--ease);
}

.ref-list-item:hover {
  background: var(--surface-2);
}

.ref-list-item.is-selected {
  background: var(--accent-soft);
}

.ref-list-item .title {
  font-weight: 650;
  font-size: 0.95rem;
}

.ref-list-item .meta {
  margin-top: 0.2rem;
  color: var(--muted);
  font-size: 0.78rem;
}

.ref-detail {
  padding: 1.1rem 1.2rem 1.35rem;
}

.ref-detail.empty {
  display: grid;
  place-items: center;
  color: var(--muted);
  min-height: 280px;
  text-align: center;
  padding: 2rem;
}

.detail-kicker {
  margin: 0 0 0.35rem;
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--accent-ink);
}

.detail-title {
  margin: 0 0 0.75rem;
  font-family: var(--font-display);
  font-size: 1.45rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1.2;
}

.formula-block {
  margin: 0 0 1rem;
  padding: 0.85rem 1rem;
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: 8px;
  font-family: var(--font-mono);
  font-size: 0.95rem;
  overflow-x: auto;
  white-space: pre-wrap;
}

.detail-section {
  margin: 0 0 0.9rem;
}

.detail-section h3 {
  margin: 0 0 0.35rem;
  font-size: 0.82rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--muted);
}

.detail-section p,
.detail-section li {
  margin: 0;
  font-size: 0.92rem;
}

.detail-section ul {
  margin: 0;
  padding-left: 1.1rem;
}

.detail-section li + li {
  margin-top: 0.25rem;
}

.tag-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
}

.tag {
  display: inline-flex;
  padding: 0.2rem 0.55rem;
  border-radius: 999px;
  background: var(--mark-soft);
  color: var(--mark);
  font-size: 0.72rem;
  font-weight: 700;
}

.detail-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
  margin-top: 1rem;
}

.btn {
  appearance: none;
  border: 1px solid var(--border);
  background: var(--surface-2);
  color: var(--text);
  border-radius: 8px;
  padding: 0.45rem 0.8rem;
  font: inherit;
  font-size: 0.85rem;
  font-weight: 650;
  cursor: pointer;
}

.btn:hover {
  border-color: var(--accent);
  background: var(--accent-soft);
}

.toast {
  position: fixed;
  bottom: 1.25rem;
  left: 50%;
  transform: translateX(-50%);
  padding: 0.55rem 1rem;
  background: var(--text);
  color: var(--bg);
  border-radius: 999px;
  font-size: 0.85rem;
  font-weight: 650;
  z-index: 50;
  box-shadow: var(--shadow);
}

.toast[hidden] {
  display: none !important;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* Periodic table */
.ptable {
  display: grid;
  grid-template-columns: repeat(18, minmax(0, 1fr));
  gap: 3px;
  margin-top: 0.75rem;
}

.ptable-el {
  aspect-ratio: 1;
  min-height: 0;
  border: 1px solid var(--border);
  border-radius: 4px;
  background: var(--surface);
  color: inherit;
  padding: 0.15rem;
  font: inherit;
  cursor: pointer;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  line-height: 1.1;
  transition: transform 0.12s var(--ease), border-color 0.12s var(--ease);
}

.ptable-el:hover,
.ptable-el.is-selected {
  transform: scale(1.04);
  border-color: var(--accent);
  z-index: 1;
}

.ptable-el .num {
  font-size: clamp(0.45rem, 0.9vw, 0.65rem);
  color: var(--muted);
}

.ptable-el .sym {
  font-weight: 700;
  font-size: clamp(0.55rem, 1.4vw, 0.85rem);
}

.ptable-el .name {
  display: none;
}

@media (min-width: 1100px) {
  .ptable-el .name {
    display: block;
    font-size: 0.5rem;
    color: var(--muted);
    max-width: 100%;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
  }
}

.cat-alkali { background: #fecaca; }
.cat-alkaline { background: #fed7aa; }
.cat-transition { background: #fde68a; }
.cat-post-transition { background: #bbf7d0; }
.cat-metalloid { background: #a5f3fc; }
.cat-nonmetal { background: #c7d2fe; }
.cat-halogen { background: #ddd6fe; }
.cat-noble { background: #fbcfe8; }
.cat-lanthanide { background: #fce7f3; }
.cat-actinide { background: #e7e5e4; }

[data-theme="dark"] .cat-alkali { background: #7f1d1d; }
[data-theme="dark"] .cat-alkaline { background: #9a3412; }
[data-theme="dark"] .cat-transition { background: #854d0e; }
[data-theme="dark"] .cat-post-transition { background: #166534; }
[data-theme="dark"] .cat-metalloid { background: #155e75; }
[data-theme="dark"] .cat-nonmetal { background: #3730a3; }
[data-theme="dark"] .cat-halogen { background: #5b21b6; }
[data-theme="dark"] .cat-noble { background: #9d174d; }
[data-theme="dark"] .cat-lanthanide { background: #9d174d; }
[data-theme="dark"] .cat-actinide { background: #44403c; }

.swatch-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
  gap: 0.55rem;
}

.swatch {
  border: 1px solid var(--border);
  border-radius: 8px;
  overflow: hidden;
  background: var(--surface);
  cursor: pointer;
  text-align: left;
  padding: 0;
  font: inherit;
  color: inherit;
}

.swatch-chip {
  height: 52px;
}

.swatch-meta {
  padding: 0.45rem 0.55rem 0.55rem;
}

.swatch-meta strong {
  display: block;
  font-size: 0.82rem;
}

.swatch-meta span {
  color: var(--muted);
  font-family: var(--font-mono);
  font-size: 0.72rem;
}

.emoji-grid {
  display: flex;
  flex-direction: column;
  gap: 0.45rem;
}

.emoji-cell {
  display: grid;
  grid-template-columns: 3.25rem minmax(0, 1fr);
  gap: 0.75rem 0.9rem;
  align-items: start;
  width: 100%;
  text-align: left;
  padding: 0.7rem 0.85rem;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--surface);
  color: inherit;
  font: inherit;
  cursor: pointer;
  transition: border-color 0.12s var(--ease), background 0.12s var(--ease);
}

.emoji-cell:hover,
.emoji-cell.is-selected {
  border-color: var(--accent);
  background: var(--accent-soft);
  transform: none;
}

.emoji-cell .glyph {
  font-size: 1.85rem;
  line-height: 1.2;
  text-align: center;
  padding-top: 0.1rem;
}

.emoji-cell .emoji-body {
  min-width: 0;
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
}

.emoji-cell .label {
  font-size: 0.95rem;
  font-weight: 650;
  color: var(--text);
  text-align: left;
  line-height: 1.3;
  max-width: none;
  overflow: visible;
  display: block;
  -webkit-line-clamp: unset;
}

.emoji-cell .codepoints {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--muted);
}

.emoji-cell .usage-line {
  margin: 0;
  font-size: 0.82rem;
  line-height: 1.4;
  color: var(--text);
}

.emoji-cell .usage-line .usage-label {
  font-weight: 700;
  font-size: 0.72rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--accent-ink);
  margin-right: 0.35rem;
}

.emoji-cell .usage-line.how .usage-label {
  color: var(--mark);
}

.emoji-hero {
  font-size: 2.4rem;
  line-height: 1.2;
}

/* Electromagnetic spectrum (Wave Desk) */
.em-spectrum-panel {
  margin: 0 0 1.25rem;
  padding: 1rem 1.1rem 1.15rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.em-spectrum-title {
  margin: 0 0 0.25rem;
  font-family: var(--font-display);
  font-size: 1.25rem;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.em-spectrum-lede {
  margin: 0 0 0.75rem;
  color: var(--muted);
  font-size: 0.9rem;
}

.em-spectrum-axis {
  display: flex;
  justify-content: space-between;
  gap: 0.75rem;
  margin-bottom: 0.4rem;
  font-size: 0.72rem;
  font-weight: 650;
  letter-spacing: 0.02em;
  text-transform: uppercase;
  color: var(--muted);
}

.em-spectrum-strip {
  display: grid;
  grid-template-columns: repeat(7, minmax(0, 1fr));
  gap: 3px;
  margin-bottom: 0.85rem;
}

@media (max-width: 720px) {
  .em-spectrum-strip {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

.em-band {
  display: flex;
  flex-direction: column;
  justify-content: flex-end;
  gap: 0.2rem;
  min-height: 72px;
  padding: 0.45rem 0.4rem;
  border: 2px solid transparent;
  border-radius: 6px;
  color: #fff;
  text-shadow: 0 1px 2px rgba(0, 0, 0, 0.45);
  font: inherit;
  cursor: pointer;
  text-align: left;
  transition: transform 0.12s var(--ease), border-color 0.12s var(--ease);
}

.em-band:hover,
.em-band.is-selected {
  transform: translateY(-2px);
  border-color: var(--text);
}

.em-band-name {
  font-size: 0.82rem;
  font-weight: 700;
}

.em-band-range {
  font-size: 0.65rem;
  line-height: 1.25;
  opacity: 0.92;
}

.em-spectrum-detail {
  margin: 0;
  box-shadow: none;
}

.em-band-swatch {
  height: 10px;
  border-radius: 999px;
  margin: 0 0 0.85rem;
  border: 1px solid var(--border);
}

.usage-when,
.usage-how {
  padding: 0.65rem 0.75rem;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--surface-2);
}

.usage-when {
  border-color: color-mix(in srgb, var(--accent) 28%, var(--border));
}

.usage-how {
  border-color: color-mix(in srgb, var(--mark) 28%, var(--border));
}

.footer-note {
  margin-top: 2rem;
  padding-top: 1rem;
  border-top: 1px solid var(--border);
  color: var(--muted);
  font-size: 0.82rem;
}

.footer-note a {
  font-weight: 650;
  text-decoration: none;
}