:root {
  color-scheme: light;
  --ink: #12211a;
  --muted: #5d6c64;
  --line: #dbe3de;
  --line-strong: #c5d0c9;
  --paper: #ffffff;
  --canvas: #f3f6f4;
  --soft: #edf4ef;
  --green: #146c43;
  --green-dark: #0d4e30;
  --green-bright: #56c58a;
  --danger: #a33131;
  --danger-soft: #fff2f2;
  --shadow: 0 18px 48px rgba(20, 51, 35, 0.08);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--ink);
  background:
    radial-gradient(circle at 83% 7%, rgba(86, 197, 138, 0.12), transparent 24rem),
    var(--canvas);
  font-size: 16px;
  line-height: 1.5;
}

button,
input,
select,
textarea {
  font: inherit;
}

button,
a {
  -webkit-tap-highlight-color: transparent;
}

.shell {
  width: min(1160px, calc(100% - 40px));
  margin-inline: auto;
}

.site-header {
  border-bottom: 1px solid rgba(197, 208, 201, 0.8);
  background: rgba(255, 255, 255, 0.8);
}

.header-content,
.footer-content,
.panel-heading,
.section-heading,
.requirements-heading,
.submit-row,
.utilisation-copy {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.header-content {
  min-height: 72px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 11px;
  color: var(--ink);
  font-weight: 750;
  letter-spacing: -0.02em;
  text-decoration: none;
}

.brand-mark {
  display: grid;
  width: 34px;
  height: 34px;
  place-items: center;
  border-radius: 9px;
  color: white;
  background: var(--green);
  font-size: 15px;
}

.github-link {
  color: var(--muted);
  font-size: 14px;
  font-weight: 650;
  text-decoration: none;
}

.github-link:hover {
  color: var(--green);
}

.hero {
  max-width: 760px;
  padding: 76px 0 40px;
}

.eyebrow,
.step-label {
  margin: 0 0 10px;
  color: var(--green);
  font-size: 12px;
  font-weight: 800;
  letter-spacing: 0.13em;
  text-transform: uppercase;
}

h1,
h2,
h3,
p {
  margin-top: 0;
}

h1 {
  max-width: 700px;
  margin-bottom: 18px;
  font-size: clamp(2.65rem, 6vw, 4.8rem);
  line-height: 0.99;
  letter-spacing: -0.065em;
}

.hero > p:last-child {
  max-width: 680px;
  margin: 0;
  color: var(--muted);
  font-size: 18px;
}

h2 {
  margin-bottom: 0;
  font-size: clamp(1.55rem, 3vw, 2rem);
  line-height: 1.2;
  letter-spacing: -0.035em;
}

h3 {
  margin-bottom: 4px;
  font-size: 17px;
}

.panel {
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 18px;
  background: var(--paper);
  box-shadow: var(--shadow);
}

.input-panel {
  padding: clamp(24px, 5vw, 48px);
}

.panel-heading {
  padding-bottom: 32px;
  border-bottom: 1px solid var(--line);
}

.button {
  display: inline-flex;
  min-height: 42px;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 9px 15px;
  border: 1px solid transparent;
  border-radius: 9px;
  cursor: pointer;
  font-weight: 720;
  transition: border-color 150ms ease, background 150ms ease, color 150ms ease, transform 150ms ease;
}

.button:hover {
  transform: translateY(-1px);
}

.button:focus-visible,
input:focus-visible,
select:focus-visible,
textarea:focus-visible,
summary:focus-visible,
.remove-row-button:focus-visible,
a:focus-visible {
  outline: 3px solid rgba(86, 197, 138, 0.45);
  outline-offset: 2px;
}

.button-primary {
  min-height: 50px;
  padding-inline: 22px;
  color: white;
  background: var(--green);
}

.button-primary:hover {
  background: var(--green-dark);
}

.button-secondary,
.button-quiet {
  border-color: var(--line-strong);
  color: var(--ink);
  background: var(--paper);
}

.button-secondary:hover,
.button-quiet:hover {
  border-color: var(--green);
  color: var(--green-dark);
  background: var(--soft);
}

.field-group {
  position: relative;
}

.parent-field {
  max-width: 620px;
  padding: 34px 0 42px;
}

.network-options {
  display: grid;
  grid-template-columns: minmax(0, 1.25fr) repeat(2, minmax(220px, 0.75fr));
  gap: 24px;
}

.network-options .parent-field {
  max-width: none;
}

.mode-field {
  padding: 34px 0 42px;
}

.field-group label,
.column-picker legend {
  display: block;
  margin-bottom: 8px;
  font-size: 14px;
  font-weight: 750;
}

.input-hint {
  position: absolute;
  top: 35px;
  right: 0;
  color: var(--muted);
  font-size: 12px;
}

input[type="text"],
input[type="number"],
select,
textarea {
  width: 100%;
  height: 48px;
  padding: 0 14px;
  border: 1px solid var(--line-strong);
  border-radius: 8px;
  color: var(--ink);
  background: #fbfcfb;
}

input[type="text"]:hover,
input[type="number"]:hover,
select:hover,
textarea:hover {
  border-color: #9eada4;
}

select {
  appearance: none;
  padding-right: 42px;
  background-image:
    linear-gradient(45deg, transparent 50%, var(--muted) 50%),
    linear-gradient(135deg, var(--muted) 50%, transparent 50%);
  background-position:
    calc(100% - 19px) 21px,
    calc(100% - 14px) 21px;
  background-repeat: no-repeat;
  background-size: 5px 5px, 5px 5px;
}

.mode-hint {
  margin-top: 8px;
  color: var(--muted);
  font-size: 12px;
}

#parent-cidr,
.subnet-hosts,
.results-table td:not(:first-child),
.summary-card strong,
.version {
  font-family: "SFMono-Regular", Consolas, "Liberation Mono", monospace;
}

#parent-cidr {
  height: 56px;
  font-size: 18px;
  font-weight: 650;
}

.requirements-heading {
  align-items: end;
  margin-bottom: 16px;
}

.requirements-heading p,
.submit-row p {
  margin: 0;
  color: var(--muted);
  font-size: 13px;
}

.row-actions,
.export-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.requirements-table-wrap,
.results-table-wrap {
  overflow-x: auto;
  border: 1px solid var(--line);
  border-radius: 10px;
}

.requirements-table {
  min-width: 680px;
}

table {
  width: 100%;
  border-collapse: collapse;
}

th {
  padding: 12px 14px;
  color: var(--muted);
  background: #f6f8f7;
  font-size: 11px;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-align: left;
  text-transform: uppercase;
}

td {
  padding: 10px 14px;
  border-top: 1px solid var(--line);
}

.requirements-table th:nth-child(2) {
  width: 120px;
}

.requirements-table th:nth-child(3) {
  width: 220px;
}

.requirements-table th:last-child,
.requirements-table td:last-child {
  width: 96px;
  text-align: right;
}

.requirements-table input {
  height: 42px;
  border-color: transparent;
  background: transparent;
}

.requirements-table input:hover,
.requirements-table input:focus {
  border-color: var(--line-strong);
  background: var(--paper);
}

.remove-row-button {
  border: 0;
  color: var(--muted);
  background: transparent;
  cursor: pointer;
  font-size: 13px;
  font-weight: 700;
}

.remove-row-button:hover {
  color: var(--danger);
}

.column-picker {
  margin: 32px 0 0;
  padding: 0;
  border: 0;
}

.checkbox-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(145px, 1fr));
  gap: 8px;
}

.checkbox-grid label {
  display: flex;
  min-height: 42px;
  align-items: center;
  gap: 9px;
  padding: 9px 11px;
  border: 1px solid var(--line);
  border-radius: 8px;
  cursor: pointer;
  font-size: 13px;
  font-weight: 650;
}

.checkbox-grid label:has(input:checked) {
  border-color: #a8c9b6;
  color: var(--green-dark);
  background: var(--soft);
}

input[type="checkbox"] {
  width: 16px;
  height: 16px;
  accent-color: var(--green);
}

.messages {
  margin-top: 24px;
  padding: 14px 16px;
  border: 1px solid #e7bcbc;
  border-radius: 8px;
  color: #772323;
  background: var(--danger-soft);
  font-size: 14px;
}

.messages ul {
  margin: 0;
  padding-left: 20px;
}

.messages.notice {
  border-color: #b7d9c6;
  color: var(--green-dark);
  background: var(--soft);
}

.submit-row {
  margin-top: 32px;
  padding-top: 28px;
  border-top: 1px solid var(--line);
}

.results {
  padding: 72px 0 24px;
}

.section-heading {
  align-items: end;
  margin-bottom: 24px;
}

.result-mode {
  margin: 6px 0 0;
  color: var(--muted);
  font-size: 13px;
  font-weight: 700;
}

.summary-grid {
  display: grid;
  grid-template-columns: 1.35fr repeat(4, 1fr);
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: var(--paper);
  box-shadow: var(--shadow);
}

.summary-card {
  min-width: 0;
  padding: 23px 20px;
  border-left: 1px solid var(--line);
}

.summary-card:first-child {
  border-left: 0;
}

.summary-card span,
.summary-card small {
  display: block;
  overflow: hidden;
  color: var(--muted);
  font-size: 12px;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.summary-card strong {
  display: block;
  overflow: hidden;
  margin: 6px 0 3px;
  font-size: clamp(1.1rem, 2.4vw, 1.5rem);
  text-overflow: ellipsis;
}

.summary-primary {
  color: white;
  background: var(--green-dark);
}

.summary-primary span,
.summary-primary small {
  color: #c2dfce;
}

.utilisation-card {
  margin: 14px 0 24px;
  padding: 20px;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: var(--paper);
}

.utilisation-copy {
  margin-bottom: 10px;
  font-size: 13px;
  font-weight: 700;
}

.progress-track {
  height: 10px;
  overflow: hidden;
  border-radius: 99px;
  background: #e5ebe7;
}

.progress-track span {
  display: block;
  width: 0;
  height: 100%;
  border-radius: inherit;
  background: linear-gradient(90deg, var(--green), var(--green-bright));
  transition: width 350ms ease;
}

.results-table-wrap {
  background: var(--paper);
  box-shadow: var(--shadow);
}

.results-table {
  min-width: 760px;
}

.results-table td {
  height: 56px;
  white-space: nowrap;
}

.results-table td:first-child {
  font-weight: 720;
}

.results-table tbody tr:hover {
  background: #f5faf7;
}

.result-status {
  min-height: 24px;
  margin: 12px 0 0;
  color: var(--green-dark);
  font-size: 13px;
  font-weight: 650;
}

.utilities-shell {
  margin-top: 48px;
}

.utilities-menu > summary {
  display: flex;
  min-height: 84px;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  padding: 20px clamp(24px, 5vw, 48px);
  cursor: pointer;
  list-style: none;
}

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

.utilities-menu > summary::after {
  content: "+";
  display: grid;
  width: 34px;
  height: 34px;
  flex: 0 0 auto;
  place-items: center;
  border: 1px solid var(--line-strong);
  border-radius: 50%;
  color: var(--green-dark);
  font-size: 22px;
  font-weight: 500;
}

.utilities-menu[open] > summary::after {
  content: "−";
}

.utilities-menu > summary strong,
.utilities-menu > summary small {
  display: block;
}

.utilities-menu > summary strong {
  font-size: 17px;
}

.utilities-menu > summary small {
  margin-top: 3px;
  color: var(--muted);
}

.utilities-content {
  padding: 0 clamp(24px, 5vw, 48px) clamp(24px, 5vw, 48px);
  border-top: 1px solid var(--line);
}

.utility-block {
  padding-top: 32px;
}

.utility-block + .utility-block {
  margin-top: 36px;
  border-top: 1px solid var(--line);
}

.utility-heading {
  align-items: flex-start;
  margin-bottom: 24px;
}

.utility-heading p:last-child {
  margin: 8px 0 0;
  color: var(--muted);
}

.overlap-form,
.route-summary-form {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr)) auto;
  align-items: end;
  gap: 16px;
}

.overlap-form .button {
  min-height: 48px;
}

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

.route-summary-form .button {
  min-height: 48px;
}

textarea {
  min-height: 142px;
  padding: 12px 14px;
  resize: vertical;
  line-height: 1.5;
}

.overlap-result {
  margin: 20px 0 0;
  padding: 13px 15px;
  border: 1px solid var(--line);
  border-radius: 8px;
  font-size: 14px;
  font-weight: 650;
}

.overlap-result.is-clear {
  border-color: #b7d9c6;
  color: var(--green-dark);
  background: var(--soft);
}

.overlap-result.is-overlap,
.overlap-result.is-error {
  border-color: #e7bcbc;
  color: #772323;
  background: var(--danger-soft);
}

.route-summary-result {
  margin-top: 20px;
  padding: 16px;
  border: 1px solid #b7d9c6;
  border-radius: 8px;
  color: var(--green-dark);
  background: var(--soft);
}

.route-summary-result.is-error {
  border-color: #e7bcbc;
  color: #772323;
  background: var(--danger-soft);
}

.route-summary-result p {
  margin-bottom: 10px;
  font-size: 14px;
  font-weight: 650;
}

.route-summary-result ul {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.route-summary-result li {
  padding: 5px 8px;
  border: 1px solid rgba(20, 108, 67, 0.22);
  border-radius: 6px;
  background: var(--paper);
  font-family: "SFMono-Regular", Consolas, "Liberation Mono", monospace;
  font-size: 13px;
}

footer {
  margin-top: 64px;
  border-top: 1px solid var(--line);
  color: var(--muted);
  background: var(--paper);
}

.footer-content {
  min-height: 88px;
  font-size: 13px;
}

.version {
  margin-left: 6px;
  padding: 3px 6px;
  border-radius: 5px;
  color: var(--green-dark);
  background: var(--soft);
  font-size: 11px;
}

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

[hidden] {
  display: none !important;
}

@media (max-width: 900px) {
  .network-options,
  .overlap-form,
  .route-summary-form {
    grid-template-columns: 1fr;
  }

  .mode-field {
    padding-top: 0;
  }

  .overlap-form .button {
    justify-self: start;
  }

  .route-summary-form .button {
    justify-self: start;
  }

  .summary-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .summary-card:nth-child(odd) {
    border-left: 0;
  }

  .summary-card:nth-child(n + 3) {
    border-top: 1px solid var(--line);
  }

  .summary-primary {
    grid-column: 1 / -1;
  }

  .summary-card:nth-child(2) {
    border-left: 0;
  }
}

@media (max-width: 700px) {
  .shell {
    width: min(100% - 24px, 1160px);
  }

  .hero {
    padding-top: 52px;
  }

  .header-content,
  .panel-heading,
  .section-heading,
  .requirements-heading,
  .submit-row,
  .footer-content {
    align-items: stretch;
    flex-direction: column;
  }

  .header-content,
  .footer-content {
    min-height: auto;
    align-items: flex-start;
    padding-block: 18px;
    gap: 10px;
  }

  .github-link {
    display: none;
  }

  .panel-heading {
    align-items: flex-start;
  }

  .input-hint {
    position: static;
    margin: -5px 0 8px;
  }

  .row-actions,
  .export-actions {
    width: 100%;
  }

  .row-actions .button,
  .export-actions .button {
    flex: 1 1 auto;
  }

  .requirements-table th:nth-child(2) {
    width: 85px;
  }

  .requirements-table th:nth-child(3) {
    width: 130px;
  }

  .requirements-table th,
  .requirements-table td {
    padding-inline: 8px;
  }

  .requirements-table th:last-child,
  .requirements-table td:last-child {
    width: 54px;
  }

  .remove-row-button {
    width: 32px;
    overflow: hidden;
    font-size: 0;
  }

  .remove-row-button::after {
    content: "×";
    font-size: 22px;
  }

  .submit-row .button {
    width: 100%;
  }

  .overlap-form .button {
    width: 100%;
  }

  .route-summary-form .button {
    width: 100%;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    transition-duration: 0.01ms !important;
  }
}