:root {
  color-scheme: light;
  --bg: #f5f6f8;
  --surface: #ffffff;
  --surface-sunken: #f1f3f6;
  --border: #e1e4ea;
  --border-strong: #cdd2da;
  --text: #15181e;
  --text-muted: #5b6371;
  --text-faint: #858c99;
  --accent: #2456d3;
  --accent-soft: #e9effd;
  --host: #a8510b;
  --host-soft: #fcf0e2;
  --danger: #b42318;
  --danger-soft: #fdeceb;
  --success: #067647;
  --warn: #b54708;
  --warn-soft: #fef4e2;
  /* Categorical series (validated for this surface: scripts/validate_palette.js, dataviz skill) */
  --series-1: #2a78d6;
  --series-2: #eb6834;
  --series-3: #1baf7a;
  --series-4: #eda100;
  --series-5: #e87ba4;
  --series-6: #008300;
  --series-7: #4a3aa7;
  --series-8: #e34948;
  --series-other: #898781;
  --shadow: 0 1px 2px rgb(16 24 40 / 0.04), 0 1px 3px rgb(16 24 40 / 0.06);
  --shadow-pop: 0 6px 20px rgb(16 24 40 / 0.14);
  --radius: 14px;
  --radius-sm: 10px;
  --sans: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --mono: ui-monospace, "SF Mono", SFMono-Regular, Menlo, Consolas, "Liberation Mono", monospace;
}

/* Dark palette: follows the OS setting unless the page is explicitly set to light, and
   applies whenever it is explicitly set to dark (data-theme on <html>). */
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    color-scheme: dark;
    --bg: #0e1116;
    --surface: #161a21;
    --surface-sunken: #1d222a;
    --border: #272d37;
    --border-strong: #363d49;
    --text: #e7e9ed;
    --text-muted: #a0a7b3;
    --text-faint: #6f7784;
    --accent: #82a6ff;
    --accent-soft: #1c2641;
    --host: #f0a75e;
    --host-soft: #2e2216;
    --danger: #ff8f85;
    --danger-soft: #3a1a18;
    --success: #5fd49a;
    --warn: #f7b955;
    --warn-soft: #33260f;
    --series-1: #3987e5;
    --series-2: #d95926;
    --series-3: #199e70;
    --series-4: #c98500;
    --series-5: #d55181;
    --series-6: #008300;
    --series-7: #9085e9;
    --series-8: #e66767;
    --series-other: #898781;
    --shadow: none;
    --shadow-pop: 0 6px 20px rgb(0 0 0 / 0.5);
  }
}

:root[data-theme="dark"] {
  color-scheme: dark;
  --bg: #0e1116;
  --surface: #161a21;
  --surface-sunken: #1d222a;
  --border: #272d37;
  --border-strong: #363d49;
  --text: #e7e9ed;
  --text-muted: #a0a7b3;
  --text-faint: #6f7784;
  --accent: #82a6ff;
  --accent-soft: #1c2641;
  --host: #f0a75e;
  --host-soft: #2e2216;
  --danger: #ff8f85;
  --danger-soft: #3a1a18;
  --success: #5fd49a;
  --warn: #f7b955;
  --warn-soft: #33260f;
  --series-1: #3987e5;
  --series-2: #d95926;
  --series-3: #199e70;
  --series-4: #c98500;
  --series-5: #d55181;
  --series-6: #008300;
  --series-7: #9085e9;
  --series-8: #e66767;
  --series-other: #898781;
  --shadow: none;
  --shadow-pop: 0 6px 20px rgb(0 0 0 / 0.5);
}

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

[hidden] {
  display: none !important;
}

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

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--sans);
  font-size: 15px;
  line-height: 1.5;
}

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

code {
  font-family: var(--mono);
  font-size: 0.92em;
  padding: 1px 5px;
  border-radius: 5px;
  background: var(--surface-sunken);
}

sup {
  font-size: 0.68em;
  line-height: 0;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: -1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
}

.container {
  width: 100%;
  max-width: 960px;
  margin: 0 auto;
  padding: 0 16px;
}

.site-header {
  padding: 40px 0 24px;
}

.site-header h1 {
  margin: 0;
  font-size: 28px;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.tagline {
  margin: 4px 0 0;
  color: var(--text-muted);
}

/* ---------- Header primer: formulas + RFCs ---------- */

.primer {
  display: grid;
  gap: 18px;
  margin-top: 22px;
  padding-top: 18px;
  border-top: 1px solid var(--border);
}

.primer-section + .primer-section {
  padding-top: 18px;
  border-top: 1px solid var(--border);
}

.primer-head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 2px 12px;
  margin-bottom: 10px;
}

.primer-title {
  margin: 0;
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--text-muted);
}

.primer-hint {
  font-size: 13px;
  color: var(--text-faint);
}

.primer-hint-mono {
  font-family: var(--mono);
}

.formula-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.formula-chips li {
  padding: 6px 12px;
  font: 14px/1.4 var(--mono);
  color: var(--text);
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 8px;
}

.op {
  font-weight: 700;
  letter-spacing: 0.02em;
  color: var(--accent);
}

.primer-details {
  margin-top: 10px;
}

.primer-details > summary {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  font-size: 14px;
  font-weight: 600;
  color: var(--accent);
  list-style: none;
  cursor: pointer;
}

.primer-details > summary::-webkit-details-marker {
  display: none;
}

.primer-details > summary::before {
  content: "";
  border-top: 4px solid transparent;
  border-bottom: 4px solid transparent;
  border-left: 6px solid currentColor;
  transition: transform 0.15s;
}

.primer-details[open] > summary::before {
  transform: rotate(90deg);
}

.primer-details > summary:hover {
  text-decoration: underline;
}

.formula-steps {
  margin-top: 12px;
  padding: 4px 16px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
}

.formula-step {
  display: grid;
  grid-template-columns: 11rem 12.5rem minmax(0, 1fr);
  gap: 4px 20px;
  align-items: baseline;
  padding: 9px 0;
  border-top: 1px solid var(--border);
}

.formula-step:first-child {
  border-top: 0;
}

.formula-head {
  padding-bottom: 4px;
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--text-faint);
}

.formula-name {
  font-size: 14px;
  font-weight: 600;
  color: var(--text);
}

.formula-name small {
  display: block;
  font-size: 12.5px;
  font-weight: 400;
  color: var(--text-muted);
}

.formula-rule,
.formula-work {
  font: 13px/1.5 var(--mono);
  overflow-wrap: anywhere;
}

.formula-rule {
  color: var(--text);
}

.formula-work {
  color: var(--text-muted);
}

.formula-work strong {
  font-weight: 700;
  color: var(--text);
}

.formula-notes {
  display: grid;
  gap: 6px;
  max-width: 80ch;
  margin: 12px 0 0;
  padding-left: 18px;
  font-size: 14px;
  color: var(--text-muted);
}

.rfc-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.rfc-chip {
  display: inline-flex;
  align-items: baseline;
  gap: 8px;
  padding: 5px 12px;
  font: inherit;
  font-size: 13px;
  color: var(--text-muted);
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 999px;
  cursor: pointer;
}

.rfc-chip b {
  font-family: var(--mono);
  font-weight: 600;
  color: var(--accent);
}

.rfc-chip:hover {
  border-color: var(--accent);
}

/* An RFC mentioned in running text: opens its explanation in the header. */
.rfc-link {
  padding: 0;
  font: inherit;
  color: var(--accent);
  background: none;
  border: 0;
  border-bottom: 1px dotted currentColor;
  cursor: pointer;
}

.rfc-link:hover {
  border-bottom-style: solid;
}

.rfc-list {
  display: grid;
  gap: 10px;
  margin-top: 12px;
}

.rfc-entry {
  padding: 12px 16px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  transition: border-color 0.4s, box-shadow 0.4s;
}

.rfc-entry:focus {
  outline: none;
}

.rfc-entry.is-highlighted {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-soft);
}

.rfc-entry h3 {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 2px 10px;
  margin: 0;
  font-size: 15px;
  font-weight: 600;
  text-wrap: balance;
}

.rfc-num {
  font-family: var(--mono);
  color: var(--accent);
  white-space: nowrap;
}

.rfc-meta {
  margin: 2px 0 0;
  font-size: 12.5px;
  color: var(--text-faint);
}

.rfc-meta a {
  white-space: nowrap;
}

.rfc-summary {
  max-width: 80ch;
  margin: 6px 0 0;
  font-size: 14px;
  color: var(--text-muted);
}

@media (prefers-reduced-motion: reduce) {
  .rfc-entry,
  .primer-details > summary::before {
    transition: none;
  }
}

main,
.output {
  display: grid;
  gap: 16px;
  min-width: 0;
}

.output {
  transition: opacity 0.15s;
}

.output.is-stale {
  opacity: 0.45;
}

.card {
  min-width: 0;
  padding: 20px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.card-head {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px 10px;
  margin-bottom: 16px;
}

.card-head h2 {
  margin: 0 4px 0 0;
  font-size: 16px;
  font-weight: 650;
}

.field-label {
  display: block;
  margin-bottom: 6px;
  font-size: 13px;
  font-weight: 600;
  color: var(--text-muted);
}

/* ---------- Input ---------- */

.ip-input {
  width: 100%;
  padding: 12px 14px;
  font: 500 22px/1.3 var(--mono);
  color: var(--text);
  background: var(--surface-sunken);
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-sm);
}

.ip-input:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-soft);
}

.ip-input[aria-invalid="true"] {
  border-color: var(--danger);
}

.ip-input[aria-invalid="true"]:focus {
  box-shadow: 0 0 0 3px var(--danger-soft);
}

.error {
  margin: 10px 0 0;
  padding: 8px 12px;
  font-size: 14px;
  color: var(--danger);
  background: var(--danger-soft);
  border-radius: 8px;
}

.hint {
  margin: 8px 0 0;
  font-size: 13px;
  color: var(--text-muted);
}

.prefix {
  margin-top: 20px;
}

.prefix-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
}

.prefix-info {
  font: 600 14px var(--mono);
  color: var(--accent);
}

.prefix-control {
  display: flex;
  align-items: center;
  gap: 10px;
}

.prefix-control input[type="range"] {
  flex: 1;
  min-width: 0;
  margin: 0;
  accent-color: var(--accent);
}

.step {
  flex: 0 0 auto;
  width: 34px;
  height: 34px;
  font-size: 18px;
  line-height: 1;
  color: var(--text);
  background: var(--surface);
  border: 1px solid var(--border-strong);
  border-radius: 8px;
  cursor: pointer;
}

.step:hover:not(:disabled) {
  border-color: var(--accent);
  color: var(--accent);
}

.step:disabled {
  opacity: 0.4;
  cursor: default;
}

.examples {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px;
  margin-top: 18px;
  font-size: 13px;
  color: var(--text-muted);
}

.examples > span {
  margin-right: 4px;
}

.chip {
  padding: 4px 10px;
  font: 13px var(--mono);
  color: var(--text);
  background: var(--surface-sunken);
  border: 1px solid var(--border);
  border-radius: 999px;
  cursor: pointer;
}

.chip:hover {
  border-color: var(--accent);
  color: var(--accent);
}

/* ---------- Results ---------- */

.badge,
.pill {
  padding: 3px 10px;
  font-size: 13px;
  font-weight: 600;
  border-radius: 999px;
}

.badge {
  font-family: var(--mono);
  color: var(--accent);
  background: var(--accent-soft);
}

.pill {
  color: var(--text-muted);
  background: var(--surface-sunken);
}

.summary {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  margin: 0 0 12px;
}

.tile {
  position: relative;
  min-width: 0;
  padding: 12px 44px 14px 14px;
  background: var(--surface-sunken);
  border-radius: var(--radius-sm);
}

.tile dt {
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--text-muted);
}

.tile dd {
  margin: 4px 0 0;
  font: 600 19px/1.35 var(--mono);
  font-variant-numeric: tabular-nums;
}

.tile .copy {
  position: absolute;
  top: 8px;
  right: 8px;
}

.range-part {
  display: inline-block;
}

.range-sep {
  color: var(--text-faint);
  font-weight: 400;
}

.muted {
  color: var(--text-faint);
  font-weight: 400;
}

.details {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  column-gap: 32px;
  margin: 0;
}

.detail {
  display: flex;
  align-items: center;
  gap: 12px;
  min-width: 0;
  min-height: 42px;
  padding: 4px 0;
  border-bottom: 1px solid var(--border);
}

.detail dt {
  flex: 0 0 auto;
  font-size: 14px;
  color: var(--text-muted);
}

.detail dd {
  display: flex;
  align-items: center;
  gap: 2px;
  min-width: 0;
  margin: 0 0 0 auto;
}

.detail .value {
  font: 14px var(--mono);
  text-align: right;
  overflow-wrap: anywhere;
}

.detail .value .rfc {
  margin-left: 6px;
  font-family: var(--sans);
  font-size: 12px;
  white-space: nowrap;
}

.copy {
  display: inline-grid;
  flex: 0 0 auto;
  place-items: center;
  width: 28px;
  height: 28px;
  padding: 0;
  color: var(--text-faint);
  background: transparent;
  border: 0;
  border-radius: 6px;
  cursor: pointer;
}

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

.copy svg {
  width: 16px;
  height: 16px;
}

.copy .icon-check,
.copy.is-copied .icon-copy {
  display: none;
}

.copy.is-copied .icon-check {
  display: block;
}

.copy.is-copied {
  color: var(--success);
}

.copy-spacer {
  display: inline-block;
  width: 28px;
}

/* Exact figure shown under an abbreviated count such as 2⁶⁴. */
.tile .exact {
  display: block;
  margin-top: 2px;
  font-size: 12px;
  font-weight: 400;
  color: var(--text-muted);
  overflow-wrap: anywhere;
}

/* IPv6 values are long: smaller tile text, and one detail per row with values in a column. */
.summary.is-v6 .tile dd {
  font-size: 16px;
}

.details.is-v6 {
  grid-template-columns: minmax(0, 1fr);
}

.details.is-v6 .detail dt {
  flex-basis: 150px;
}

.details.is-v6 .detail dd {
  flex: 1;
  margin-left: 0;
}

.details.is-v6 .detail .value {
  flex: 1;
  text-align: left;
}

.note {
  margin: 14px 0 0;
  font-size: 14px;
  color: var(--text-muted);
}

/* ---------- Binary ---------- */

.legend {
  display: flex;
  flex-wrap: wrap;
  gap: 4px 14px;
  margin-left: auto;
  font-size: 13px;
  color: var(--text-muted);
}

.swatch {
  display: inline-block;
  width: 10px;
  height: 10px;
  margin-right: 6px;
  border-radius: 3px;
}

.swatch-net {
  background: var(--accent);
}

.swatch-host {
  background: var(--host);
}

.binary {
  display: grid;
  gap: 8px;
}

.bin-row {
  display: grid;
  grid-template-columns: 110px auto 1fr;
  align-items: center;
  gap: 16px;
  min-width: 0;
}

.bin-label {
  font-size: 13px;
  color: var(--text-muted);
}

.bits {
  min-width: 0;
  overflow-x: auto; /* last resort on very narrow screens: scroll the row, not the page */
  font: 15px/1.6 var(--mono);
  white-space: nowrap;
}

.octet {
  display: inline-block;
  overflow: hidden;
  border-radius: 4px;
}

.bit {
  display: inline-block;
  width: 1.05ch;
  text-align: center;
}

.bit.net {
  color: var(--accent);
  background: var(--accent-soft);
}

.bit.host {
  color: var(--host);
  background: var(--host-soft);
}

.bit.net + .bit.host {
  box-shadow: inset 1px 0 0 var(--host);
}

.dot {
  color: var(--text-faint);
}

.bin-dec {
  min-width: 0;
  font: 13px var(--mono);
  color: var(--text-muted);
  text-align: right;
  overflow-wrap: anywhere;
}

.binary.is-v6 {
  gap: 18px;
}

.bin-row.bin-row-v6 {
  grid-template-columns: auto minmax(0, 1fr);
  gap: 4px 16px;
}

.bin-row-v6 .hextets {
  grid-column: 1 / -1;
}

.hextets {
  display: grid;
  grid-template-columns: repeat(4, max-content);
  gap: 6px 14px;
  font: 14px/1.5 var(--mono);
}

.hextet {
  display: flex;
  flex-direction: column;
  align-items: center;
}

.hextet-hex {
  font-size: 11px;
  line-height: 1.4;
  color: var(--text-faint);
}

.hextet-bits {
  display: inline-block;
  overflow: hidden;
  white-space: nowrap;
  border-radius: 4px;
}

/* ---------- Split ---------- */

.split-controls {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px 12px;
}

.split-controls .field-label {
  margin: 0;
}

select {
  min-width: 0;
  max-width: 100%;
  padding: 8px 12px;
  font: 14px var(--sans);
  color: var(--text);
  background: var(--surface);
  border: 1px solid var(--border-strong);
  border-radius: 8px;
}

.split-summary {
  margin: 12px 0;
  font-size: 14px;
  color: var(--text-muted);
}

.split-summary strong {
  color: var(--text);
  font-weight: 600;
}

.table-wrap {
  max-height: 520px;
  overflow: auto;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
}

table {
  width: 100%;
  border-collapse: collapse;
  font-size: 14px;
}

th {
  position: sticky;
  top: 0;
  padding: 8px 12px;
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-align: left;
  text-transform: uppercase;
  white-space: nowrap;
  color: var(--text-muted);
  background: var(--surface-sunken);
}

td {
  padding: 7px 12px;
  font-family: var(--mono);
  font-variant-numeric: tabular-nums;
  white-space: nowrap;
  border-top: 1px solid var(--border);
}

.num {
  text-align: right;
}

td.num:first-child {
  color: var(--text-faint);
}

tr.is-current td {
  background: var(--accent-soft);
}

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

a:hover {
  text-decoration: underline;
}

.btn {
  padding: 8px 14px;
  font: 600 14px var(--sans);
  color: var(--text);
  background: var(--surface);
  border: 1px solid var(--border-strong);
  border-radius: 8px;
  cursor: pointer;
}

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

.show-more {
  margin-top: 12px;
}

/* ---------- VLSM planner ---------- */

.vlsm {
  position: relative; /* anchors the bar tooltip */
}

.btn-small {
  margin-left: auto;
  padding: 5px 10px;
  font-size: 13px;
}

.section-intro {
  margin: -6px 0 16px;
  font-size: 14px;
  color: var(--text-muted);
}

.section-intro strong {
  font-family: var(--mono);
  font-weight: 600;
  color: var(--text);
}

.vlsm-row {
  display: grid;
  grid-template-columns: 10px minmax(0, 1fr) 130px 32px;
  gap: 8px;
  align-items: center;
  margin-bottom: 8px;
}

.vlsm-row-head {
  margin-bottom: 4px;
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--text-muted);
}

.vlsm-row-head .num {
  padding-right: 11px;
}

.swatch-dot {
  width: 10px;
  height: 10px;
  border-radius: 3px;
}

.vlsm-row input {
  width: 100%;
  min-width: 0;
  padding: 8px 10px;
  font: 14px var(--sans);
  color: var(--text);
  background: var(--surface-sunken);
  border: 1px solid var(--border-strong);
  border-radius: 8px;
}

.vlsm-row .vlsm-size {
  font-family: var(--mono);
  text-align: right;
}

.vlsm-row input:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-soft);
}

.vlsm-row input[aria-invalid="true"] {
  border-color: var(--danger);
}

.remove {
  width: 32px;
  height: 32px;
  padding: 0;
  font-size: 20px;
  line-height: 1;
  color: var(--text-faint);
  background: transparent;
  border: 0;
  border-radius: 6px;
  cursor: pointer;
}

.remove:hover {
  color: var(--danger);
  background: var(--danger-soft);
}

.vlsm-actions {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px 18px;
  margin-top: 4px;
}

.check-wrap {
  display: inline-flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 4px 8px;
  font-size: 14px;
}

.check {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 14px;
  color: var(--text-muted);
  cursor: pointer;
}

.check input {
  width: 16px;
  height: 16px;
  margin: 0;
  accent-color: var(--accent);
}

/* Address-space bar: one segment per placed subnet, striped track = free space. */
.usage-bar {
  position: relative;
  height: 28px;
  margin-top: 22px;
  overflow: hidden;
  border-radius: 4px;
  background:
    repeating-linear-gradient(135deg, transparent 0 5px, var(--border) 5px 6px),
    var(--surface-sunken);
  box-shadow: inset 0 0 0 1px var(--border);
}

.seg {
  position: absolute;
  top: 0;
  bottom: 0;
  min-width: 3px;
  box-shadow: inset -2px 0 0 var(--surface); /* 2px gap between neighbours */
}

.usage-summary {
  margin: 10px 0 0;
  font-size: 14px;
  color: var(--text-muted);
}

.usage-summary strong {
  font-weight: 600;
  color: var(--text);
}

.warning {
  display: flex;
  gap: 10px;
  margin: 14px 0 0;
  padding: 10px 12px;
  font-size: 14px;
  color: var(--text);
  background: var(--warn-soft);
  border-radius: 8px;
}

.warning svg {
  flex: 0 0 auto;
  width: 18px;
  height: 18px;
  margin-top: 1px;
  color: var(--warn);
}

.warning ul {
  margin: 2px 0 0;
  padding-left: 18px;
}

.vlsm-table {
  margin-top: 14px;
}

td.name {
  font-family: var(--sans);
}

.swatch-inline {
  display: inline-block;
  width: 10px;
  height: 10px;
  margin-right: 8px;
  border-radius: 3px;
  vertical-align: -1px;
}

.free-list {
  margin: 12px 0 0;
  font-size: 14px;
  line-height: 1.7;
  color: var(--text-muted);
}

.free-list strong {
  font-weight: 600;
  color: var(--text);
}

.free-list a {
  font-family: var(--mono);
  white-space: nowrap;
}

.tooltip {
  position: absolute;
  z-index: 5;
  padding: 8px 10px;
  font-size: 13px;
  line-height: 1.45;
  white-space: nowrap;
  color: var(--text-muted);
  background: var(--surface);
  border: 1px solid var(--border-strong);
  border-radius: 8px;
  box-shadow: var(--shadow-pop);
  transform: translate(-50%, calc(-100% - 8px));
  pointer-events: none;
}

.tooltip strong {
  display: block;
  color: var(--text);
}

.tooltip .mono {
  font-family: var(--mono);
  color: var(--text);
}

.site-footer {
  padding: 8px 0 40px;
  font-size: 13px;
  text-align: center;
  color: var(--text-faint);
}

/* ---------- Small screens ---------- */

@media (max-width: 720px) {
  .details {
    grid-template-columns: minmax(0, 1fr);
  }

  .formula-step {
    grid-template-columns: minmax(0, 1fr);
    gap: 2px;
  }

  .formula-head {
    display: none;
  }

  .formula-work::before {
    content: "→ ";
    color: var(--text-faint);
  }

  .bin-row {
    grid-template-columns: minmax(0, 1fr) auto;
    gap: 0 12px;
  }

  .bin-row .bits {
    grid-column: 1 / -1;
    grid-row: 2;
  }
}

@media (max-width: 600px) {
  .site-header {
    padding: 28px 0 18px;
  }

  .site-header h1 {
    font-size: 24px;
  }

  .card {
    padding: 16px;
  }

  .ip-input {
    font-size: 19px;
  }

  .summary {
    grid-template-columns: minmax(0, 1fr);
  }

  .tile dd {
    font-size: 17px;
  }

  .bits {
    font-size: 13px;
  }

  .legend {
    margin-left: 0;
  }

  .hextets {
    grid-template-columns: repeat(2, max-content);
    font-size: 13px;
  }

  .details.is-v6 .detail {
    flex-wrap: wrap;
    gap: 0 12px;
    padding: 6px 0;
  }

  .details.is-v6 .detail dt {
    flex-basis: 100%;
    font-size: 13px;
  }

  .vlsm-row {
    grid-template-columns: 10px minmax(0, 1fr) 84px 32px;
    gap: 6px;
  }

  .btn-small {
    margin-left: 0;
  }
}

@media (max-width: 380px) {
  .bits,
  .hextets {
    font-size: 12px;
  }
}

@media (max-width: 360px) {
  .card {
    padding: 14px;
  }

  .bits,
  .hextets {
    font-size: 11px;
  }
}