/* style.css */
:root {
  color-scheme: dark;
  --bg: #090d19;
  --bg-glow: #192551;
  --surface: rgba(18, 26, 48, .82);
  --surface-2: rgba(27, 39, 69, .78);
  --surface-3: #28385d;
  --text: #f2f5ff;
  --muted: #aebbd5;
  --faint: #7383a3;
  --border: rgba(190, 207, 255, .15);
  --border-strong: rgba(190, 207, 255, .25);
  --accent: #ae91ff;
  --accent-strong: #805cf5;
  --accent-soft: rgba(158, 125, 255, .16);
  --secondary: #52dfbe;
  --danger: #ff728c;
  --warning: #f6c15c;
  --shadow: 0 20px 60px rgba(0, 0, 0, .28);
  --card-highlight: rgba(255, 255, 255, .035);
}

:root[data-mode="light"] {
  color-scheme: light;
  --bg: #f4f7fe;
  --bg-glow: #dce7ff;
  --surface: rgba(255, 255, 255, .84);
  --surface-2: rgba(241, 245, 253, .88);
  --surface-3: #e5ebf8;
  --text: #17223c;
  --muted: #596984;
  --faint: #7887a2;
  --border: rgba(50, 70, 113, .15);
  --border-strong: rgba(50, 70, 113, .24);
  --accent-soft: rgba(124, 92, 255, .12);
  --shadow: 0 18px 45px rgba(58, 78, 122, .12);
  --card-highlight: rgba(255, 255, 255, .65);
}

:root[data-scheme="ocean"] {
  --accent: #4aceff;
  --accent-strong: #187ee8;
  --accent-soft: rgba(65, 201, 255, .17);
  --secondary: #4cdebe;
}

:root[data-scheme="forest"] {
  --accent: #7cdc99;
  --accent-strong: #24975a;
  --accent-soft: rgba(116, 217, 148, .17);
  --secondary: #afea6d;
}

:root[data-scheme="sunset"] {
  --accent: #ff9f76;
  --accent-strong: #dd5f64;
  --accent-soft: rgba(255, 156, 112, .18);
  --secondary: #f2cf68;
}

* {
  box-sizing: border-box;
}

html {
  min-width: 320px;
  scroll-behavior: smooth;
}

body {
  min-height: 100vh;
  margin: 0;
  overflow-x: hidden;
  background:
    radial-gradient(circle at 88% -7%, var(--bg-glow), transparent 31rem),
    radial-gradient(circle at -12% 40%, var(--accent-soft), transparent 30rem),
    linear-gradient(145deg, var(--bg), color-mix(in srgb, var(--bg) 92%, #000));
  color: var(--text);
  font-family: Inter, ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  line-height: 1.5;
}

body::before {
  position: fixed;
  z-index: -1;
  inset: 0;
  pointer-events: none;
  content: "";
  opacity: .2;
  background-image:
    linear-gradient(rgba(255,255,255,.025) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,.025) 1px, transparent 1px);
  background-size: 34px 34px;
  mask-image: linear-gradient(to bottom, black, transparent 62%);
}

button,
input,
select {
  font: inherit;
}

button {
  cursor: pointer;
}

button,
select,
input,
summary {
  -webkit-tap-highlight-color: transparent;
}

button:focus-visible,
input:focus-visible,
select:focus-visible,
summary:focus-visible {
  outline: 3px solid var(--accent);
  outline-offset: 3px;
}

button:disabled {
  cursor: default;
}

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

.app-shell {
  width: min(1180px, calc(100% - 28px));
  margin: 0 auto;
  padding: 18px 0 36px;
}

.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 52px;
  gap: 12px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--text);
  text-decoration: none;
  font-size: 1.1rem;
  font-weight: 700;
  letter-spacing: -.03em;
}

.brand b {
  color: var(--accent);
}

.brand-mark {
  display: grid;
  width: 23px;
  grid-template-columns: repeat(2, 8px);
  gap: 3px;
  transform: rotate(45deg);
}

.brand-mark i {
  display: block;
  aspect-ratio: 1;
  border-radius: 2px;
  background: var(--accent);
  box-shadow: 0 0 10px var(--accent-soft);
}

.brand-mark i:nth-child(2),
.brand-mark i:nth-child(3) {
  background: var(--secondary);
}

.toolbar {
  display: flex;
  align-items: center;
  gap: 8px;
}

.scheme-picker select,
.icon-button {
  height: 44px;
  border: 1px solid var(--border);
  border-radius: 12px;
  color: var(--text);
  background: var(--surface);
  box-shadow: inset 0 1px 0 var(--card-highlight);
  transition: border-color .18s ease, background .18s ease, transform .18s ease;
}

.scheme-picker select:hover,
.icon-button:hover {
  border-color: var(--border-strong);
  background: var(--surface-2);
}

.scheme-picker select {
  width: 142px;
  padding: 0 30px 0 11px;
  font-size: .78rem;
  font-weight: 650;
}

.icon-button {
  width: 44px;
  padding: 0;
  font-size: 1.12rem;
}

.icon-button:active,
.text-button:active,
.preset-button:active,
.calculate-button:active,
.next-button:active {
  transform: translateY(1px);
}

.theme-sun {
  display: none;
}

:root[data-mode="light"] .theme-sun {
  display: inline;
}

:root[data-mode="light"] .theme-moon {
  display: none;
}

.hero {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 28px;
  padding: 62px 0 42px;
}

.hero-content {
  max-width: 760px;
}

.eyebrow,
.result-label {
  margin: 0 0 8px;
  color: var(--accent);
  font-size: .68rem;
  font-weight: 850;
  letter-spacing: .14em;
  text-transform: uppercase;
}

.hero .eyebrow {
  display: flex;
  align-items: center;
  gap: 8px;
}

.hero .eyebrow span {
  width: 18px;
  height: 1px;
  background: currentColor;
  box-shadow: 5px 0 0 var(--secondary);
}

h1,
h2,
h3,
h4,
p {
  margin-top: 0;
}

h1 {
  max-width: 760px;
  margin-bottom: 15px;
  font-size: clamp(2.25rem, 6vw, 4.5rem);
  line-height: .97;
  letter-spacing: -.072em;
}

h2 {
  margin-bottom: 0;
  font-size: clamp(1.5rem, 3vw, 2.15rem);
  line-height: 1.05;
  letter-spacing: -.052em;
}

h3 {
  margin-bottom: 12px;
  font-size: 1.08rem;
  letter-spacing: -.03em;
}

.hero-copy {
  max-width: 625px;
  margin-bottom: 0;
  color: var(--muted);
  font-size: 1.04rem;
}

.hero-badge {
  position: relative;
  display: flex;
  flex: 0 0 auto;
  align-items: center;
  gap: 11px;
  min-width: 158px;
  padding: 15px 18px;
  overflow: hidden;
  border: 1px solid var(--border);
  border-radius: 17px;
  background: linear-gradient(135deg, var(--accent-soft), var(--surface));
  box-shadow: var(--shadow), inset 0 1px 0 var(--card-highlight);
  color: var(--muted);
  font-size: .72rem;
  line-height: 1.3;
}

.badge-orbit {
  position: absolute;
  top: -28px;
  right: -25px;
  width: 83px;
  height: 83px;
  border: 1px solid color-mix(in srgb, var(--accent) 48%, transparent);
  border-radius: 50%;
}

.badge-orbit::after {
  position: absolute;
  top: 16px;
  left: 6px;
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--secondary);
  box-shadow: 0 0 12px var(--secondary);
  content: "";
}

.hero-badge strong {
  z-index: 1;
  color: var(--accent);
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 1.8rem;
  letter-spacing: -.1em;
}

.hero-badge span {
  z-index: 1;
}

.card {
  border: 1px solid var(--border);
  border-radius: 21px;
  background: linear-gradient(145deg, var(--card-highlight), transparent 45%), var(--surface);
  box-shadow: var(--shadow);
  backdrop-filter: blur(18px);
}

.calculator {
  padding: clamp(19px, 4vw, 34px);
}

.section-heading,
.map-heading,
.card-title-row,
.quiz-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 15px;
}

.text-button {
  min-height: 44px;
  padding: 0 12px;
  border: 0;
  border-radius: 9px;
  color: var(--accent);
  background: transparent;
  font-size: .83rem;
  font-weight: 780;
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 4px;
  transition: background .18s ease, transform .18s ease;
}

.text-button:hover {
  background: var(--accent-soft);
}

.input-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 12px;
  margin-top: 25px;
}

.field {
  display: block;
}

.field > span {
  display: block;
  margin: 0 0 7px;
  color: var(--muted);
  font-size: .79rem;
  font-weight: 740;
}

.field em {
  color: var(--faint);
  font-size: .71rem;
  font-style: normal;
  font-weight: 500;
}

.field input {
  width: 100%;
  height: 53px;
  padding: 0 14px;
  border: 1px solid var(--border);
  border-radius: 12px;
  color: var(--text);
  background: var(--surface-2);
  box-shadow: inset 0 1px 1px rgba(0,0,0,.08);
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: .94rem;
  transition: border-color .18s ease, box-shadow .18s ease, background .18s ease;
}

.field input::placeholder {
  color: var(--faint);
}

.field input:hover {
  border-color: var(--border-strong);
}

.field input:focus {
  border-color: var(--accent);
  background: color-mix(in srgb, var(--surface-2) 88%, var(--accent-soft));
  box-shadow: 0 0 0 4px var(--accent-soft);
  outline: none;
}

.field small {
  display: block;
  margin: 6px 2px 0;
  color: var(--faint);
  font-size: .7rem;
}

.calculate-button,
.next-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 9px;
  min-height: 53px;
  padding: 0 20px;
  align-self: end;
  border: 0;
  border-radius: 12px;
  color: #fff;
  background: linear-gradient(135deg, var(--accent-strong), color-mix(in srgb, var(--accent-strong) 72%, var(--accent)));
  box-shadow: 0 11px 24px var(--accent-soft), inset 0 1px 0 rgba(255,255,255,.25);
  font-size: .87rem;
  font-weight: 820;
  transition: transform .18s ease, filter .18s ease, box-shadow .18s ease;
}

.calculate-button:hover,
.next-button:hover {
  filter: brightness(1.08);
  box-shadow: 0 14px 28px var(--accent-soft), inset 0 1px 0 rgba(255,255,255,.25);
  transform: translateY(-1px);
}

.calculate-button b {
  font-size: 1.17rem;
  font-weight: 500;
}

.preset-row {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 7px;
  margin-top: 15px;
}

.preset-row > span {
  margin-right: 2px;
  color: var(--faint);
  font-size: .7rem;
  font-weight: 700;
}

.preset-button {
  min-height: 31px;
  padding: 5px 9px;
  border: 1px solid var(--border);
  border-radius: 999px;
  color: var(--muted);
  background: color-mix(in srgb, var(--surface-2) 84%, transparent);
  font-size: .68rem;
  font-weight: 700;
  transition: color .18s ease, border-color .18s ease, background .18s ease, transform .18s ease;
}

.preset-button:hover {
  border-color: color-mix(in srgb, var(--accent) 55%, var(--border));
  color: var(--text);
  background: var(--accent-soft);
}

.form-error {
  min-height: 1.3em;
  margin: 10px 2px 0;
  color: var(--danger);
  font-size: .82rem;
  font-weight: 650;
}

.result-area {
  margin-top: 28px;
}

.results-updated .network-banner,
.results-updated .metric,
.results-updated .map-section,
.results-updated .detail-card {
  animation: settle-in .42s ease both;
}

.results-updated .metric:nth-child(2) {
  animation-delay: .03s;
}

.results-updated .metric:nth-child(3) {
  animation-delay: .06s;
}

.results-updated .metric:nth-child(4) {
  animation-delay: .09s;
}

@keyframes settle-in {
  from {
    opacity: .72;
    transform: translateY(4px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.network-banner {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 17px;
  overflow: hidden;
  border: 1px solid color-mix(in srgb, var(--accent) 35%, var(--border));
  border-radius: 16px;
  background:
    radial-gradient(circle at 94% 0%, var(--accent-soft), transparent 12rem),
    linear-gradient(105deg, var(--accent-soft), transparent 70%);
}

.network-banner::after {
  position: absolute;
  right: 0;
  bottom: 0;
  width: 38%;
  height: 2px;
  background: linear-gradient(90deg, transparent, var(--accent));
  content: "";
}

.network-banner strong {
  display: block;
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: clamp(1.32rem, 4vw, 2.12rem);
  line-height: 1.1;
  letter-spacing: -.06em;
}

.address-kind,
.pill,
.range-label {
  display: inline-flex;
  flex: 0 0 auto;
  align-items: center;
  border: 1px solid color-mix(in srgb, var(--accent) 40%, transparent);
  border-radius: 999px;
  color: var(--accent);
  background: var(--accent-soft);
  font-size: .69rem;
  font-weight: 760;
}

.address-kind {
  padding: 6px 10px;
}

.pill,
.range-label {
  padding: 5px 9px;
}

.metrics-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 10px;
  margin: 12px 0;
}

.metric {
  position: relative;
  min-width: 0;
  padding: 15px;
  overflow: hidden;
  border: 1px solid var(--border);
  border-radius: 14px;
  background: var(--surface-2);
  box-shadow: inset 0 1px 0 var(--card-highlight);
}

.metric::before {
  position: absolute;
  top: 0;
  left: 15px;
  width: 24px;
  height: 2px;
  border-radius: 99px;
  background: var(--border-strong);
  content: "";
}

.metric.accent-metric::before {
  width: 42px;
  background: var(--accent);
}

.metric-label {
  display: block;
  color: var(--muted);
  font-size: .68rem;
  font-weight: 760;
  letter-spacing: .09em;
  text-transform: uppercase;
}

.metric strong {
  display: block;
  margin: 7px 0 3px;
  overflow: hidden;
  font-size: clamp(.95rem, 3vw, 1.25rem);
  letter-spacing: -.04em;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.metric small {
  color: var(--faint);
  font-size: .67rem;
}

.accent-metric {
  border-color: color-mix(in srgb, var(--accent) 36%, var(--border));
}

.map-section {
  padding: 22px 0;
}

.map-heading h3 {
  margin: 0;
}

.address-map {
  display: grid;
  grid-template-columns: 1fr;
  gap: 7px;
  margin-top: 15px;
}

.map-segment {
  position: relative;
  min-width: 0;
  padding: 14px;
  overflow: hidden;
  border: 1px solid transparent;
  border-radius: 12px;
}

.map-segment::after {
  position: absolute;
  top: 13px;
  right: 13px;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  content: "";
}

.map-segment span,
.map-segment small {
  display: block;
  font-size: .69rem;
}

.map-segment span {
  margin-bottom: 6px;
  color: var(--muted);
  font-weight: 700;
}

.map-segment b {
  display: block;
  overflow: hidden;
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: .77rem;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.map-segment small {
  margin-top: 5px;
  color: var(--faint);
}

.network-segment {
  border-color: color-mix(in srgb, var(--accent) 18%, transparent);
  background: color-mix(in srgb, var(--accent) 14%, var(--surface-2));
}

.network-segment::after {
  background: var(--accent);
  box-shadow: 0 0 10px var(--accent);
}

.host-segment {
  border-color: color-mix(in srgb, var(--secondary) 18%, transparent);
  background: color-mix(in srgb, var(--secondary) 12%, var(--surface-2));
}

.host-segment::after {
  background: var(--secondary);
  box-shadow: 0 0 10px var(--secondary);
}

.broadcast-segment {
  border-color: color-mix(in srgb, var(--warning) 18%, transparent);
  background: color-mix(in srgb, var(--warning) 11%, var(--surface-2));
}

.broadcast-segment::after {
  background: var(--warning);
  box-shadow: 0 0 10px var(--warning);
}

.special-notice {
  margin-top: 10px;
  padding: 10px 12px;
  border-left: 3px solid var(--warning);
  border-radius: 0 9px 9px 0;
  color: var(--muted);
  background: color-mix(in srgb, var(--warning) 8%, var(--surface-2));
  font-size: .78rem;
}

.details-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 12px;
}

.detail-card {
  padding: 18px;
  border: 1px solid var(--border);
  border-radius: 15px;
  background: var(--surface-2);
  box-shadow: inset 0 1px 0 var(--card-highlight);
}

.binary-row {
  display: grid;
  grid-template-columns: 31px 1fr;
  align-items: center;
  gap: 8px;
  margin: 7px 0;
}

.binary-decimal {
  color: var(--faint);
  font-family: ui-monospace, monospace;
  font-size: .7rem;
  text-align: right;
}

.bits {
  display: grid;
  grid-template-columns: repeat(8, 1fr);
  gap: 3px;
}

.bit {
  padding: 4px 0;
  border-radius: 4px;
  color: #fff;
  font-family: ui-monospace, monospace;
  font-size: clamp(.6rem, 2vw, .73rem);
  text-align: center;
}

.network-bit {
  background: linear-gradient(145deg, var(--accent), var(--accent-strong));
}

.host-bit {
  background: color-mix(in srgb, var(--secondary) 70%, #1c4852);
}

.legend {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 13px;
  color: var(--muted);
  font-size: .7rem;
}

.legend i {
  display: inline-block;
  width: 8px;
  height: 8px;
  margin-right: 4px;
  border-radius: 50%;
}

.network-dot {
  background: var(--accent);
  box-shadow: 0 0 7px var(--accent);
}

.host-dot {
  background: var(--secondary);
  box-shadow: 0 0 7px var(--secondary);
}

.routing-notes {
  display: grid;
  gap: 11px;
}

.routing-note {
  padding-left: 10px;
  border-left: 2px solid var(--accent);
}

.routing-note strong,
.routing-note span {
  display: block;
}

.routing-note strong {
  margin-bottom: 2px;
  color: var(--text);
  font-size: .78rem;
}

.routing-note span {
  color: var(--muted);
  font-size: .76rem;
  line-height: 1.43;
}

.advanced-details {
  margin-top: 12px;
  border: 1px solid var(--border);
  border-radius: 13px;
  background: var(--surface-2);
  overflow: hidden;
}

.advanced-details summary {
  display: flex;
  justify-content: space-between;
  padding: 15px;
  color: var(--text);
  cursor: pointer;
  font-size: .85rem;
  font-weight: 750;
}

.advanced-details summary span {
  color: var(--accent);
  font-size: 1.2rem;
  transition: transform .18s ease;
}

.advanced-details[open] summary span {
  transform: rotate(45deg);
}

.advanced-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1px;
  border-top: 1px solid var(--border);
}

.advanced-grid div {
  min-width: 0;
  padding: 12px;
  background: color-mix(in srgb, var(--surface-3) 42%, transparent);
}

.advanced-grid span,
.advanced-grid strong {
  display: block;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.advanced-grid span {
  color: var(--faint);
  font-size: .64rem;
  letter-spacing: .08em;
  text-transform: uppercase;
}

.advanced-grid strong {
  margin-top: 4px;
  font-family: ui-monospace, monospace;
  font-size: .7rem;
}

.learn-section {
  padding-top: 70px;
}

.learn-intro {
  max-width: 610px;
  margin-bottom: 20px;
}

.learn-intro p:last-child {
  margin: 9px 0 0;
  color: var(--muted);
}

.learn-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 12px;
}

.tutorial,
.quiz {
  padding: 20px;
}

.lesson-number {
  display: grid;
  width: 30px;
  height: 30px;
  margin-bottom: 15px;
  place-items: center;
  border: 1px solid color-mix(in srgb, var(--accent) 30%, transparent);
  border-radius: 8px;
  color: var(--accent);
  background: var(--accent-soft);
  font-size: .72rem;
  font-weight: 900;
}

.tutorial > p,
.muted {
  color: var(--muted);
  font-size: .84rem;
}

.lesson-items {
  display: grid;
  gap: 12px;
}

.lesson-items p {
  display: grid;
  gap: 2px;
  margin: 0;
}

.lesson-items b {
  font-size: .79rem;
}

.lesson-items span {
  color: var(--muted);
  font-size: .76rem;
}

.tip {
  margin-top: 17px;
  padding: 11px;
  border: 1px solid color-mix(in srgb, var(--secondary) 16%, transparent);
  border-radius: 10px;
  color: var(--muted);
  background: color-mix(in srgb, var(--secondary) 7%, var(--surface-2));
  font-size: .75rem;
}

.tip strong {
  color: var(--secondary);
}

.prefix-example {
  margin: 16px 0;
  padding: 13px;
  overflow: auto;
  border: 1px solid var(--border);
  border-radius: 11px;
  background: var(--surface-2);
}

.prefix-example div {
  font-family: ui-monospace, monospace;
  font-size: .76rem;
  white-space: nowrap;
}

.prefix-network {
  color: var(--accent);
}

.prefix-host {
  color: var(--secondary);
}

.prefix-example strong {
  display: block;
  margin-top: 8px;
  color: var(--muted);
  font-size: .7rem;
}

.quiz {
  display: flex;
  flex-direction: column;
}

.quiz-header {
  align-items: center;
}

.quiz-header h3 {
  margin: 0;
}

.quiz-header .eyebrow {
  margin-bottom: 4px;
}

#quizProgress {
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 4px 8px;
  color: var(--faint);
  font-size: .7rem;
  font-weight: 750;
}

.question {
  margin: 23px 0 14px;
  font-size: .92rem;
  font-weight: 700;
  line-height: 1.38;
}

.answer-list {
  display: grid;
  gap: 8px;
}

.answer-button {
  display: flex;
  width: 100%;
  min-height: 46px;
  align-items: center;
  gap: 10px;
  padding: 7px 10px;
  border: 1px solid var(--border);
  border-radius: 10px;
  color: var(--text);
  background: var(--surface-2);
  font-size: .78rem;
  text-align: left;
  transition: transform .16s ease, border-color .16s ease, background .16s ease;
}

.answer-button:hover:not(:disabled) {
  border-color: var(--accent);
  background: var(--accent-soft);
  transform: translateX(2px);
}

.answer-button span {
  display: grid;
  height: 25px;
  flex: 0 0 25px;
  place-items: center;
  border-radius: 6px;
  color: var(--faint);
  background: var(--surface-3);
  font-size: .7rem;
  font-weight: 800;
}

.answer-button.correct {
  border-color: var(--secondary);
  background: color-mix(in srgb, var(--secondary) 16%, var(--surface-2));
}

.answer-button.wrong {
  border-color: var(--danger);
  background: color-mix(in srgb, var(--danger) 14%, var(--surface-2));
}

.quiz-feedback {
  min-height: 0;
  margin-top: 13px;
  font-size: .76rem;
  line-height: 1.45;
}

.quiz-feedback:not(:empty) {
  padding: 10px;
  border-radius: 9px;
}

.quiz-feedback strong {
  display: block;
  margin-bottom: 2px;
}

.quiz-feedback.success {
  color: var(--text);
  background: color-mix(in srgb, var(--secondary) 14%, var(--surface-2));
}

.quiz-feedback.success strong {
  color: var(--secondary);
}

.quiz-feedback.retry {
  color: var(--text);
  background: color-mix(in srgb, var(--warning) 13%, var(--surface-2));
}

.quiz-feedback.retry strong {
  color: var(--warning);
}

.next-button {
  min-height: 44px;
  margin-top: 12px;
  align-self: flex-start;
  font-size: .78rem;
}

.quiz-complete {
  padding: 18px 0 6px;
  text-align: center;
}

.score-ring {
  display: grid;
  width: 64px;
  height: 64px;
  margin: 4px auto 13px;
  place-items: center;
  border: 4px solid var(--accent);
  border-radius: 50%;
  color: var(--accent);
  box-shadow: 0 0 0 6px var(--accent-soft);
  font-size: 1rem;
  font-weight: 900;
}

.quiz-complete h4 {
  margin-bottom: 4px;
  font-size: 1rem;
}

.quiz-complete p {
  margin: 0;
  color: var(--muted);
  font-size: .78rem;
}

footer {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 7px 18px;
  padding: 28px 3px 0;
  color: var(--faint);
  font-size: .69rem;
}

@media (min-width: 600px) {
  .app-shell {
    width: min(1180px, calc(100% - 44px));
  }

  .input-grid {
    grid-template-columns: minmax(0, 1.45fr) minmax(190px, 1fr) auto;
    align-items: end;
  }

  .calculate-button {
    min-width: 138px;
  }

  .metrics-grid {
    grid-template-columns: repeat(4, 1fr);
  }

  .address-map {
    grid-template-columns: .8fr 2fr .9fr;
  }

  .map-segment {
    min-height: 106px;
  }

  .details-grid {
    grid-template-columns: 1.14fr .86fr;
  }

  .advanced-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

@media (min-width: 880px) {
  .learn-grid {
    grid-template-columns: 1fr 1fr 1.1fr;
    align-items: stretch;
  }

  .tutorial,
  .quiz {
    min-height: 334px;
  }
}

@media (max-width: 430px) {
  .hero {
    padding-top: 40px;
  }

  .hero-badge {
    display: none;
  }

  .network-banner {
    flex-direction: column;
    align-items: flex-start;
  }

  .advanced-grid {
    grid-template-columns: 1fr;
  }

  .preset-row > span {
    width: 100%;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    transition-duration: .01ms !important;
    animation-duration: .01ms !important;
    animation-iteration-count: 1 !important;
  }
}

@media (prefers-color-scheme: light) {
  :root:not([data-mode]) {
    color-scheme: light;
    --bg: #f4f7fe;
    --bg-glow: #dce7ff;
    --surface: rgba(255, 255, 255, .84);
    --surface-2: rgba(241, 245, 253, .88);
    --surface-3: #e5ebf8;
    --text: #17223c;
    --muted: #596984;
    --faint: #7887a2;
    --border: rgba(50, 70, 113, .15);
    --border-strong: rgba(50, 70, 113, .24);
    --card-highlight: rgba(255, 255, 255, .65);
  }
}