@import url('https://fonts.googleapis.com/css2?family=Noto+Sans+Sinhala:wght@400;500;600;700&display=swap');

:root {
  color-scheme: dark;
  --bg: #12151b;
  --bg-raised: #171b23;
  --surface: #1a1f28;
  --surface-raised: #202631;
  --text: #f3f6fb;
  --muted: #a3adbb;
  --soft: #778393;
  --line: rgba(177, 194, 216, .14);
  --blue: #0a84ff;
  --cyan: #00d2ff;
  --green: #61d8ad;
  --amber: #ffc66d;
  --red: #ff858b;
  --radius: 18px;
  --content: 1160px;
  font-family: "Noto Sans Sinhala", "Iskoola Pota", "Nirmala UI", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
}

* {
  box-sizing: border-box;
}

html {
  background-color: #12151b !important;
  color-scheme: dark;
  scroll-behavior: smooth;
  scroll-padding-top: 82px;
}

body {
  margin: 0;
  background-color: #12151b !important;
  background: var(--bg, #12151b) !important;
  color: #f3f6fb !important;
  color: var(--text, #f3f6fb) !important;
  font-size: 18px;
  line-height: 1.85;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}

a {
  color: inherit;
}

a:focus-visible,
summary:focus-visible {
  outline: 3px solid var(--cyan);
  outline-offset: 4px;
}

.skip-link {
  position: fixed;
  z-index: 20;
  top: 10px;
  left: 10px;
  padding: 10px 16px;
  transform: translateY(-160%);
  border-radius: 8px;
  background: var(--cyan);
  color: #071219;
  font-weight: 700;
  text-decoration: none;
}

.skip-link:focus {
  transform: translateY(0);
}

.site-header {
  position: sticky;
  z-index: 10;
  top: 0;
  border-bottom: 1px solid var(--line);
  background: rgba(18, 21, 27, .88);
  backdrop-filter: blur(18px);
}

.header-inner {
  display: flex;
  width: min(100% - 48px, var(--content));
  min-height: 72px;
  margin: 0 auto;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 11px;
  color: var(--text);
  font-size: 1.15rem;
  font-weight: 700;
  text-decoration: none;
  white-space: nowrap;
}

.main-nav {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: clamp(13px, 2.2vw, 28px);
}

.main-nav a {
  color: var(--muted);
  font-size: .98rem;
  text-decoration: none;
  transition: color .2s ease;
}

.main-nav a:hover {
  color: var(--cyan);
}

.hero {
  position: relative;
  display: grid;
  overflow: hidden;
  min-height: min(720px, calc(100svh - 72px));
  grid-template-columns: minmax(0, 1.2fr) minmax(300px, .8fr);
  align-items: center;
  width: min(100% - 48px, var(--content));
  margin: 0 auto;
  padding: 84px 0 102px;
}

.hero-grid {
  position: absolute;
  z-index: -1;
  top: 0;
  right: -14vw;
  bottom: 0;
  left: 22%;
  pointer-events: none;
  background-image: linear-gradient(rgba(128, 165, 207, .04) 1px, transparent 1px), linear-gradient(90deg, rgba(128, 165, 207, .04) 1px, transparent 1px);
  background-size: 58px 58px;
  mask-image: linear-gradient(90deg, transparent, #000 25%, #000 78%, transparent);
}

.hero-content {
  position: relative;
  z-index: 1;
  max-width: 700px;
}

.eyebrow,
.section-kicker {
  display: flex;
  margin: 0;
  align-items: center;
  gap: 10px;
  color: var(--cyan);
  font-size: .96rem;
  font-weight: 700;
  letter-spacing: .04em;
}

.eyebrow-line {
  width: 26px;
  height: 1px;
  background: var(--cyan);
}

.eyebrow-dot,
.section-kicker span {
  color: var(--soft);
}

.hero h1 {
  max-width: 700px;
  margin: 22px 0 18px;
  font-size: clamp(2.4rem, 5.3vw, 4.45rem);
  font-weight: 700;
  letter-spacing: -.04em;
  line-height: 1.32;
}

.hero h1 span,
.closing h2 span {
  color: var(--cyan);
}

.hero-lead {
  max-width: 560px;
  margin: 0;
  color: var(--muted);
  font-size: clamp(1rem, 1.4vw, 1.12rem);
}

.hero-actions {
  display: flex;
  margin-top: 30px;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px;
}

.button {
  display: inline-flex;
  min-height: 48px;
  padding: 9px 17px;
  align-items: center;
  justify-content: center;
  gap: 10px;
  border: 1px solid transparent;
  border-radius: 10px;
  font-size: 1.02rem;
  font-weight: 700;
  text-decoration: none;
  transition: transform .2s ease, background .2s ease, border-color .2s ease;
}

.button:hover {
  transform: translateY(-2px);
}

.button-primary {
  background: #0056b3;
  color: white;
  box-shadow: 0 8px 26px rgba(10, 132, 255, .22);
}

.button-primary:hover {
  background: #086bc7;
}

.button-quiet {
  border-color: var(--line);
  background: rgba(255, 255, 255, .025);
  color: var(--text);
}

.button-quiet:hover {
  border-color: rgba(0, 210, 255, .45);
  background: rgba(0, 210, 255, .06);
}

.hero-facts {
  display: flex;
  margin-top: 48px;
  flex-wrap: wrap;
  gap: 30px;
}

.hero-facts div {
  display: grid;
  grid-template-columns: auto 1fr;
  align-items: center;
  column-gap: 9px;
  color: var(--soft);
  font-size: .95rem;
}

.fact-number {
  grid-row: span 2;
  color: var(--text);
  font-family: "Segoe UI", sans-serif;
  font-size: 1.25rem;
  font-weight: 700;
}

.hero-art {
  position: relative;
  display: grid;
  width: min(100%, 430px);
  aspect-ratio: 1;
  margin: auto;
  place-items: center;
}

.orbit {
  position: absolute;
  border: 1px solid rgba(0, 210, 255, .22);
  border-radius: 50%;
}

.orbit-outer {
  width: 96%;
  height: 96%;
  background: radial-gradient(circle, rgba(0, 210, 255, .035), transparent 64%);
}

.orbit-inner {
  width: 72%;
  height: 72%;
  border-color: rgba(10, 132, 255, .4);
  box-shadow: 0 0 45px rgba(10, 132, 255, .08), inset 0 0 45px rgba(10, 132, 255, .04);
}

.orbit-core {
  width: 48%;
  height: 48%;
  border-color: rgba(0, 210, 255, .3);
  border-style: dashed;
}

.orbit-center {
  position: relative;
  display: grid;
  width: 116px;
  height: 116px;
  place-items: center;
  border: 1px solid rgba(0, 210, 255, .52);
  border-radius: 34px;
  background: linear-gradient(145deg, #1c3446, #17212d 70%);
  box-shadow: 0 0 75px rgba(0, 210, 255, .16), 0 18px 40px rgba(0, 0, 0, .3);
  color: var(--cyan);
  font-size: 3rem;
  transform: rotate(45deg);
}

.orbit-center span {
  transform: rotate(-45deg);
}

.orbit-label {
  position: absolute;
  padding: 5px 11px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: #171d25;
  color: var(--muted);
  font-size: .95rem;
}

.orbit-label-top {
  top: 2%;
  left: 50%;
  transform: translateX(-50%);
}

.orbit-label-right {
  top: 50%;
  right: -3%;
  transform: translateY(-50%);
}

.orbit-label-bottom {
  bottom: 2%;
  left: 50%;
  transform: translateX(-50%);
}

.orbit-label-left {
  top: 50%;
  left: -3%;
  transform: translateY(-50%);
}

.orbit-spark {
  position: absolute;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--cyan);
  box-shadow: 0 0 18px 4px rgba(0, 210, 255, .55);
}

.spark-one {
  top: 19%;
  right: 22%;
}

.spark-two {
  bottom: 21%;
  left: 18%;
  width: 6px;
  height: 6px;
  background: var(--blue);
  box-shadow: 0 0 18px 4px rgba(10, 132, 255, .6);
}

.hero-bottom {
  position: absolute;
  right: 0;
  bottom: 25px;
  left: 0;
  display: flex;
  justify-content: space-between;
  color: var(--soft);
  font-size: .92rem;
}

.hero-bottom span:last-child {
  color: #8995a3;
}

.section {
  width: min(100% - 48px, var(--content));
  margin: 0 auto;
  padding: 100px 0;
  border-top: 1px solid var(--line);
}

.section-heading {
  max-width: 750px;
  margin-bottom: 38px;
}

.section-kicker {
  margin-bottom: 12px;
  font-family: "Segoe UI", sans-serif;
  font-size: .96rem;
}

.section-heading h2 {
  margin: 0;
  font-size: clamp(1.8rem, 3.3vw, 2.65rem);
  letter-spacing: -.025em;
  line-height: 1.45;
}

.section-intro {
  max-width: 680px;
  margin: 10px 0 0;
  color: var(--muted);
  font-size: 1.18rem; line-height: 1.85;
}

.definition-card {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  overflow: hidden;
  padding: clamp(22px, 4vw, 38px);
  border: 1px solid rgba(0, 210, 255, .2);
  border-radius: var(--radius);
  background: linear-gradient(120deg, rgba(10, 132, 255, .1), transparent 68%), var(--surface);
}

.definition-icon,
.small-icon {
  display: grid;
  width: 48px;
  height: 48px;
  place-items: center;
  border: 1px solid rgba(0, 210, 255, .35);
  border-radius: 14px;
  background: rgba(0, 210, 255, .08);
  color: var(--cyan);
  font-size: 1.35rem;
}

.card-label {
  margin: 0;
  color: var(--cyan);
  font-size: .95rem;
  font-weight: 700;
}

.definition-text {
  max-width: 900px;
  margin: 4px 0 10px;
  font-size: clamp(1.15rem, 2.3vw, 1.65rem);
  font-weight: 600;
  line-height: 1.75;
}

.definition-note {
  margin: 0;
  color: var(--muted);
  font-size: 1.05rem; line-height: 1.8;
}

.definition-index {
  position: absolute;
  right: 24px;
  bottom: -37px;
  color: rgba(184, 203, 225, .035);
  font-family: "Segoe UI", sans-serif;
  font-size: 8rem;
  font-weight: 800;
  line-height: 1;
  pointer-events: none;
}

.needs-grid,
.sustain-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px;
}

.need-card,
.sustain-card {
  padding: clamp(22px, 3.5vw, 32px);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
}

.need-card-main {
  background: linear-gradient(145deg, rgba(10, 132, 255, .09), transparent 60%), var(--surface);
}

.card-topline,
.sustain-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
}

.card-symbol,
.sustain-symbol {
  display: grid;
  width: 42px;
  height: 42px;
  place-items: center;
  border: 1px solid rgba(10, 132, 255, .34);
  border-radius: 12px;
  background: rgba(10, 132, 255, .11);
  color: #65b6ff;
  font-size: 1.04rem;
  font-weight: 700;
}

.card-symbol-cyan {
  border-color: rgba(0, 210, 255, .33);
  background: rgba(0, 210, 255, .08);
  color: var(--cyan);
}

.pill {
  padding: 4px 10px;
  border: 1px solid rgba(10, 132, 255, .28);
  border-radius: 999px;
  background: rgba(10, 132, 255, .08);
  color: #8fc8ff;
  font-size: .88rem; font-weight: 600;
  white-space: nowrap;
}

.pill-cyan {
  border-color: rgba(0, 210, 255, .25);
  background: rgba(0, 210, 255, .06);
  color: #81e9fb;
}

.need-card h3,
.sustain-card h3 {
  margin: 18px 0 8px;
  font-size: 1.34rem;
}

.need-card > p, .sustain-card > p {
  margin: 0;
  color: var(--muted);
  font-size: 1.08rem; line-height: 1.8;
}

.example-box {
  margin-top: 24px;
  padding: 16px 18px;
  border-left: 2px solid var(--blue);
  border-radius: 0 10px 10px 0;
  background: rgba(10, 132, 255, .07);
}

.example-box > span, .local-example strong {
  color: #8fc8ff;
  font-size: .95rem;
  font-weight: 700;
}

.example-box p, .local-example p {
  margin: 5px 0 0;
  color: #c4ceda;
  font-size: 1.02rem; line-height: 1.8;
}

.insight-strip {
  display: flex;
  margin-top: 18px;
  padding: 19px 22px;
  align-items: flex-start;
  gap: 14px;
  border: 1px solid rgba(255, 198, 109, .2);
  border-radius: 12px;
  background: rgba(255, 198, 109, .045);
}

.insight-mark {
  display: grid;
  width: 26px;
  height: 26px;
  flex: 0 0 auto;
  place-items: center;
  border-radius: 50%;
  background: rgba(255, 198, 109, .12);
  color: var(--amber);
  font-family: "Segoe UI", sans-serif;
  font-weight: 700;
}

.insight-strip p {
  margin: 0;
  color: var(--muted);
  font-size: 1.05rem; line-height: 1.8;
}

.insight-strip strong {
  color: var(--amber);
}

.timeline-section {
  overflow: hidden;
}

.timeline {
  position: relative;
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 12px;
  padding-top: 24px;
}

.timeline::before {
  position: absolute;
  top: 36px;
  right: 6%;
  left: 6%;
  height: 1px;
  background: linear-gradient(90deg, var(--blue), var(--cyan), rgba(0, 210, 255, .2));
  content: "";
}

.era-card {
  position: relative;
  z-index: 1;
  align-self: start;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 13px;
  background: var(--surface);
  transition: border-color .2s ease, transform .2s ease;
}

.era-card:hover,
.era-card[open] {
  border-color: rgba(0, 210, 255, .45);
}

.era-card[open] {
  transform: translateY(-3px);
  background: linear-gradient(180deg, rgba(10, 132, 255, .09), transparent 75%), var(--surface);
}

.era-card summary {
  display: grid;
  min-height: 125px;
  padding: 13px 14px;
  align-content: start;
  justify-items: start;
  gap: 7px;
  cursor: pointer;
  list-style: none;
}

.era-card summary::-webkit-details-marker {
  display: none;
}

.era-marker {
  display: grid;
  width: 25px;
  height: 25px;
  place-items: center;
  border: 1px solid rgba(0, 210, 255, .35);
  border-radius: 50%;
  background: #152630;
  color: var(--cyan);
  font-family: "Segoe UI", sans-serif;
  font-size: .92rem;
  font-weight: 700;
}

.era-name {
  padding-right: 12px;
  font-size: 1.25rem;
  font-weight: 700;
  line-height: 1.5;
}

.era-arrow {
  position: absolute;
  top: 15px;
  right: 13px;
  color: var(--cyan);
  font-family: "Segoe UI", sans-serif;
  font-size: 1.05rem;
  transition: transform .2s ease;
}

.era-card[open] .era-arrow {
  transform: rotate(45deg);
}

.era-content {
  padding: 0 14px 16px;
}

.era-caption {
  margin: 0 0 6px;
  color: var(--cyan);
  font-size: .95rem;
  font-weight: 700;
}

.era-content p:last-child {
  margin: 0;
  color: var(--muted);
  font-size: 1.05rem; line-height: 1.8;
  line-height: 1.75;
}

.era-content .era-caption:not(:first-child) {
  margin-top: 13px;
}

.era-highlights {
  display: flex;
  margin: 8px 0 0;
  padding: 0;
  flex-wrap: wrap;
  gap: 7px;
  list-style: none;
}

.era-highlights li {
  padding: 3px 9px;
  border: 1px solid rgba(0, 210, 255, .18);
  border-radius: 999px;
  background: rgba(0, 210, 255, .045);
  color: #b6c6d5;
  font-size: .98rem; line-height: 1.7;
  line-height: 1.7;
}

.era-inventions {
  display: grid;
  margin: 10px 0 0;
  padding: 0;
  gap: 8px;
  list-style: none;
}

.era-inventions li {
  display: grid;
  min-width: 0;
  padding: 11px 12px;
  gap: 4px;
  border: 1px solid rgba(0, 210, 255, .16);
  border-radius: 10px;
  background: rgba(0, 210, 255, .035);
}

.era-inventions strong {
  color: #d7eaff;
  font-size: 1.02rem;
}

.era-inventions span {
  color: var(--muted);
  font-size: .96rem;
  line-height: 1.75;
}

.era-inventions small {
  color: var(--cyan);
  font-size: .88rem;
  line-height: 1.65;
}

.timeline-hint {
  margin: 16px 0 0;
  color: var(--soft);
  font-size: .95rem;
}

.timeline-hint span {
  margin-right: 6px;
  color: var(--cyan);
}

.impact-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
}

.impact-card {
  position: relative;
  overflow: hidden;
  padding: 24px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
}

.impact-number {
  position: absolute;
  top: 18px;
  right: 22px;
  color: var(--soft);
  font-family: "Segoe UI", sans-serif;
  font-size: .95rem;
}

.impact-icon {
  display: grid;
  width: 43px;
  height: 43px;
  margin-bottom: 12px;
  place-items: center;
  border: 1px solid rgba(0, 210, 255, .24);
  border-radius: 13px;
  background: rgba(0, 210, 255, .07);
  color: var(--cyan);
  font-weight: 700;
}

.impact-economy {
  border-color: rgba(10, 132, 255, .28);
  background: rgba(10, 132, 255, .08);
  color: #72baff;
}

.impact-environment {
  border-color: rgba(97, 216, 173, .25);
  background: rgba(97, 216, 173, .07);
  color: var(--green);
}

.impact-card h3 {
  margin: 0 0 18px;
  font-size: 1.35rem;
}

.impact-column {
  padding: 12px 0;
  border-top: 1px solid var(--line);
}

.impact-column > span {
  color: var(--green);
  font-size: .95rem; font-weight: 700;
  font-weight: 700;
}

.impact-column p {
  margin: 4px 0 0;
  color: var(--muted);
  font-size: 1.04rem; line-height: 1.8;
}

.impact-column.impact-negative > span {
  color: var(--amber);
}

.balance-note {
  display: flex;
  margin-top: 18px;
  padding: 18px 22px;
  align-items: center;
  gap: 14px;
  border: 1px solid rgba(0, 210, 255, .18);
  border-radius: 12px;
  background: rgba(0, 210, 255, .035);
}

.balance-note > span {
  color: var(--cyan);
  font-family: "Segoe UI", sans-serif;
  font-size: 1.45rem;
}

.balance-note p {
  margin: 0;
  color: var(--muted);
  font-size: 1.05rem; line-height: 1.8;
}

.sustain-grid {
  align-items: stretch;
}

.appropriate-card {
  background: linear-gradient(150deg, rgba(10, 132, 255, .075), transparent 55%), var(--surface);
}

.sustainable-card {
  background: linear-gradient(150deg, rgba(97, 216, 173, .06), transparent 58%), var(--surface);
}

.sustain-symbol {
  width: 46px;
  height: 46px;
  font-size: .84rem;
}

.sustain-symbol-green {
  border-color: rgba(97, 216, 173, .3);
  background: rgba(97, 216, 173, .08);
  color: var(--green);
}

.pill-blue {
  border-color: rgba(10, 132, 255, .25);
  background: rgba(10, 132, 255, .07);
  color: #8fc8ff;
}

.pill-green {
  border-color: rgba(97, 216, 173, .25);
  background: rgba(97, 216, 173, .07);
  color: #8ce5c2;
}

.sustain-card .sustain-definition {
  margin-top: 0;
  color: var(--text);
  font-size: 1.12rem; line-height: 1.85;
  font-weight: 500;
}

.principle-list {
  display: grid;
  margin: 22px 0 0;
  padding: 0;
  gap: 8px;
  color: var(--muted);
  font-size: 1.04rem; line-height: 1.8;
  list-style: none;
}

.principle-list li {
  display: flex;
  align-items: flex-start;
  gap: 9px;
}

.principle-list li span {
  color: var(--cyan);
  font-weight: 700;
}

.local-example {
  margin-top: 22px;
  padding: 15px 17px;
  border-left: 2px solid var(--blue);
  border-radius: 0 10px 10px 0;
  background: rgba(10, 132, 255, .07);
}

.three-pillars {
  display: grid;
  margin-top: 24px;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 9px;
}

.three-pillars > div {
  display: flex;
  min-width: 0;
  padding: 14px 8px;
  align-items: center;
  flex-direction: column;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: rgba(255, 255, 255, .025);
  text-align: center;
}

.pillar-icon {
  display: grid;
  width: 30px;
  height: 30px;
  margin-bottom: 8px;
  place-items: center;
  border-radius: 9px;
  background: rgba(0, 210, 255, .09);
  color: var(--cyan);
  font-size: .8rem;
  font-weight: 700;
}

.pillar-prosperity {
  background: rgba(10, 132, 255, .12);
  color: #72baff;
}

.pillar-planet {
  background: rgba(97, 216, 173, .1);
  color: var(--green);
}

.three-pillars strong {
  font-size: 1.05rem;
}

.three-pillars small {
  margin-top: 4px;
  color: var(--soft);
  font-size: .88rem; line-height: 1.6;
  line-height: 1.5;
}

.sustain-card .sustain-footnote {
  margin-top: 15px;
  color: var(--soft);
  font-size: .95rem;
}

.management-strip {
  display: grid;
  margin-top: 18px;
  padding: 22px 24px;
  grid-template-columns: 42px minmax(0, 1fr) auto;
  align-items: center;
  gap: 17px;
  border: 1px solid rgba(0, 210, 255, .18);
  border-radius: 14px;
  background: linear-gradient(100deg, rgba(0, 210, 255, .06), transparent 70%), var(--bg-raised);
}

.management-mark {
  display: grid;
  width: 40px;
  height: 40px;
  place-items: center;
  border: 1px solid rgba(0, 210, 255, .3);
  border-radius: 12px;
  background: rgba(0, 210, 255, .08);
  color: var(--cyan);
  font-weight: 700;
}

.management-copy h3 {
  margin: 0;
  font-size: .93rem;
}

.management-copy p {
  margin: 5px 0 0;
  color: var(--muted);
  font-size: 1.04rem; line-height: 1.8;
}

.management-steps {
  display: flex;
  max-width: 230px;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 7px;
}

.management-steps span {
  padding: 4px 9px;
  border: 1px solid var(--line);
  border-radius: 999px;
  color: #b5c4d4;
  font-size: .95rem;
  white-space: nowrap;
}

.closing {
  position: relative;
  overflow: hidden;
  width: min(100% - 48px, var(--content));
  margin: 30px auto 80px;
  padding: clamp(35px, 6vw, 68px);
  border: 1px solid rgba(0, 210, 255, .18);
  border-radius: 22px;
  background: linear-gradient(110deg, rgba(10, 132, 255, .12), transparent 65%), #171d26;
}

.closing-glow {
  position: absolute;
  top: -130px;
  right: -30px;
  width: 310px;
  height: 310px;
  border-radius: 50%;
  background: rgba(0, 210, 255, .07);
  filter: blur(50px);
  pointer-events: none;
}

.closing h2 {
  position: relative;
  margin: 12px 0;
  font-size: clamp(1.8rem, 4vw, 3.2rem);
  line-height: 1.5;
}

.closing > p:not(.section-kicker) {
  position: relative;
  max-width: 650px;
  margin: 0;
  color: var(--muted);
  font-size: .9rem;
}

.back-to-top {
  position: relative;
  display: inline-flex;
  margin-top: 25px;
  align-items: center;
  gap: 9px;
  color: var(--cyan);
  font-size: 1.02rem;
  font-weight: 700;
  text-decoration: none;
}

.site-footer {
  display: flex;
  width: min(100% - 48px, var(--content));
  margin: 0 auto;
  padding: 22px 0 32px;
  align-items: flex-start;
  justify-content: space-between;
  gap: 16px;
  border-top: 1px solid var(--line);
  color: var(--soft);
  font-size: .95rem;
}

.site-footer p {
  margin: 0;
}

.site-footer span {
  text-align: right;
}

@media (max-width: 900px) {
  .hero {
    min-height: 620px;
    grid-template-columns: minmax(0, 1fr) minmax(250px, .7fr);
  }

  .hero-art {
    width: 100%;
  }

  .timeline {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    row-gap: 14px;
  }

  .timeline::before {
    display: none;
  }

  .era-card summary {
    min-height: 105px;
  }
}

@media (max-width: 700px) {
  html {
    scroll-padding-top: 70px;
  }

  .header-inner {
    width: min(100% - 32px, var(--content));
    min-height: 64px;
  }

  .main-nav {
    max-width: 54%;
    justify-content: flex-start;
    gap: 14px;
    overflow-x: auto;
    scrollbar-width: none;
  }

  .main-nav::-webkit-scrollbar {
    display: none;
  }

  .main-nav a {
    flex: 0 0 auto;
    font-size: .88rem;
  }

  .brand {
    gap: 8px;
    font-size: 1.02rem;
  }

  .hero,
  .section,
  .closing,
  .site-footer {
    width: min(100% - 36px, var(--content));
  }

  .hero {
    min-height: auto;
    grid-template-columns: 1fr;
    padding: 75px 0 72px;
  }

  .hero-art {
    width: min(74vw, 330px);
    margin: 38px auto 8px;
  }

  .orbit-center {
    width: 90px;
    height: 90px;
    border-radius: 27px;
    font-size: 2.4rem;
  }

  .hero-bottom {
    bottom: 20px;
  }

  .hero-bottom span:first-child {
    display: none;
  }

  .hero-bottom span:last-child {
    margin-left: auto;
  }

  .hero-facts {
    margin-top: 32px;
    gap: 17px;
  }

  .hero-facts div {
    column-gap: 6px;
    font-size: .88rem;
  }

  .fact-number {
    font-size: 1.08rem;
  }

  .section {
    padding: 72px 0;
  }

  .section-heading {
    margin-bottom: 27px;
  }

  .definition-card {
    grid-template-columns: 1fr;
    gap: 15px;
  }

  .needs-grid,
  .sustain-grid {
    grid-template-columns: 1fr;
  }

  .management-strip {
    grid-template-columns: 38px minmax(0, 1fr);
    gap: 13px;
  }

  .management-steps {
    max-width: none;
    grid-column: 1 / -1;
    justify-content: flex-start;
    padding-left: 51px;
  }

  .timeline {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

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

  .impact-card {
    padding: 22px;
  }

  .closing {
    margin-top: 12px;
    margin-bottom: 54px;
  }
}

@media (max-width: 420px) {
  .main-nav {
    max-width: calc(100% - 55px);
    gap: 10px;
  }

  .main-nav a {
    font-size: .85rem;
  }

  .hero,
  .section,
  .closing,
  .site-footer {
    width: min(100% - 28px, var(--content));
  }

  .hero h1 {
    font-size: 2.15rem;
  }

  .hero-actions {
    align-items: stretch;
    flex-direction: column;
  }

  .button {
    width: 100%;
  }

  .hero-facts {
    justify-content: space-between;
    gap: 8px;
  }

  .hero-facts div {
    column-gap: 5px;
    font-size: .85rem;
  }

  .fact-number {
    font-size: .96rem;
  }

  .timeline {
    grid-template-columns: 1fr;
    gap: 10px;
  }

  .era-card summary {
    min-height: 75px;
    grid-template-columns: 28px 1fr 18px;
    align-items: center;
    justify-items: stretch;
    gap: 10px;
  }

  .era-marker {
    grid-row: 1;
  }

  .era-name {
    grid-column: 2;
    padding: 0;
  }

  .era-arrow {
    position: static;
    grid-column: 3;
    grid-row: 1;
    justify-self: end;
  }

  .era-content {
    padding-top: 0;
  }

  .three-pillars {
    grid-template-columns: 1fr;
  }

  .three-pillars > div {
    display: grid;
    grid-template-columns: 32px 1fr;
    justify-items: start;
    padding: 10px 12px;
    column-gap: 8px;
    text-align: left;
  }

  .pillar-icon {
    grid-row: span 2;
    margin: 0;
  }

  .three-pillars small {
    margin-top: 0;
  }

  .site-footer {
    flex-direction: column;
  }

  .site-footer span {
    text-align: left;
  }
}

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

.need-card h3,
.sustain-card h3 {
  margin-top: 0;
}

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

.resource-comparison h3 {
  margin: 0;
  font-size: .95rem;
}

.resource-comparison p {
  margin: 7px 0 0;
  color: var(--muted);
  font-size: 1.05rem; line-height: 1.8;
}

.resource-comparison {
  display: grid;
  margin-top: 18px;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
}

.resource-comparison article {
  padding: 20px;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: var(--bg-raised);
}

@media (max-width: 700px) {
  .resource-comparison {
    grid-template-columns: 1fr;
  }

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

  .management-steps {
    grid-column: auto;
    justify-content: flex-start;
    padding-left: 0;
  }
}

.technology-types {
  margin-top: 32px;
  padding: clamp(24px, 4vw, 36px);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--bg-raised);
}

.technology-types > h3,
.resource-heading {
  margin: 0;
  font-size: 1.4rem;
  font-weight: 700;
  color: #f3f6fb;
}

.technology-types > p {
  max-width: 860px;
  margin: 10px 0 0;
  color: var(--muted);
  font-size: 1.08rem;
  line-height: 1.85;
}

.technology-types-grid {
  display: grid;
  margin-top: 24px;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 20px;
}

@media (max-width: 720px) {
  .technology-types-grid {
    grid-template-columns: 1fr;
    gap: 16px;
  }
}

.tech-card-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 14px;
}

.tech-icon-badge {
  font-size: 1.6rem;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 48px;
  height: 48px;
  border-radius: 14px;
  background: rgba(10, 132, 255, .12);
  border: 1px solid rgba(10, 132, 255, .28);
}

.tech-card-num {
  font-size: .95rem;
  font-weight: 700;
  color: var(--cyan);
  background: rgba(0, 210, 255, .08);
  padding: 4px 12px;
  border-radius: 999px;
  border: 1px solid rgba(0, 210, 255, .22);
  font-family: monospace;
}

.technology-types-grid article {
  padding: 22px 24px;
  border: 1px solid rgba(10, 132, 255, .22);
  border-radius: 16px;
  background: linear-gradient(145deg, rgba(10, 132, 255, .05), rgba(255, 255, 255, .02));
  transition: transform .2s ease, border-color .2s ease, box-shadow .2s ease;
}

.technology-types-grid article:hover {
  transform: translateY(-2px);
  border-color: rgba(10, 132, 255, .45);
  box-shadow: 0 8px 24px rgba(0, 0, 0, .25);
}

.technology-types-grid h4,
.need-card h4,
.sustain-subheading {
  margin: 0;
  color: #b9dfff;
  font-size: 1.22rem;
  font-weight: 700;
}

.technology-types-grid p {
  margin: 8px 0 0;
  color: #d1d8e2;
  font-size: 1.05rem;
  line-height: 1.8;
}

.process-list {
  display: grid;
  margin: 0;
  padding: 0;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 14px;
  list-style: none;
  counter-reset: none;
}

.process-list li {
  display: flex;
  min-width: 0;
  padding: 20px;
  align-items: flex-start;
  gap: 14px;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: var(--surface);
}

.process-number {
  display: grid;
  width: 36px;
  height: 36px;
  flex: 0 0 auto;
  place-items: center;
  border: 1px solid rgba(0, 210, 255, .3);
  border-radius: 11px;
  background: rgba(0, 210, 255, .07);
  color: var(--cyan);
  font-family: "Segoe UI", sans-serif;
  font-size: .95rem;
  font-weight: 700;
}

.process-list h3 {
  margin: 0;
  font-size: 1.25rem;
}

.process-list p {
  margin: 6px 0 0;
  color: var(--muted);
  font-size: 1.06rem; line-height: 1.8;
}

.process-example {
  margin-top: 16px;
}

.need-card > p + p {
  margin-top: 12px;
}

.need-card h4 {
  margin-top: 22px;
}

.check-list {
  display: grid;
  margin: 10px 0 0;
  padding-left: 20px;
  gap: 7px;
  color: var(--muted);
  font-size: 1.04rem; line-height: 1.8;
}

.resource-heading {
  margin: 28px 0 12px;
}

.resource-comparison {
  margin-top: 0;
}

.sustain-card .sustain-subheading {
  margin-top: 22px;
}

.sustain-card > p:not(.sustain-definition, .sustain-footnote) {
  margin-top: 7px;
}

@media (max-width: 900px) {
  .technology-types-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .process-list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 520px) {
  .technology-types-grid,
  .process-list {
    grid-template-columns: 1fr;
  }

  .process-list li {
    padding: 17px;
  }
}

.exam-concepts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
}

.landmark-note {
  display: grid;
  margin-top: 18px;
  padding: 18px 22px;
  grid-template-columns: minmax(0, .55fr) minmax(0, 1fr);
  align-items: center;
  gap: 16px;
  border: 1px solid rgba(0, 210, 255, .2);
  border-radius: 14px;
  background: rgba(0, 210, 255, .035);
}

.landmark-note h3 {
  margin: 0;
  color: #b9dfff;
  font-size: 1.2rem;
}

.landmark-note p {
  margin: 0;
  color: var(--muted);
  font-size: 1.05rem; line-height: 1.8;
}

.landmark-note p + p {
  margin-top: 7px;
}

.landmark-note strong {
  color: var(--cyan);
}

.exam-concept {
  padding: 22px;
  border: 1px solid var(--line);
  border-radius: 15px;
  background: var(--surface);
}

.exam-concept h3,
.management-study h3,
.industry-study h3,
.self-check h3 {
  margin: 0;
  font-size: 1.3rem;
}

.exam-concept > p,
.management-study > p,
.industry-study > div:first-child > p:last-child {
  margin: 8px 0 0;
  color: var(--muted);
  font-size: 1.06rem; line-height: 1.85;
}

.exam-concept .exam-example {
  margin-top: 14px;
  padding-top: 12px;
  border-top: 1px solid var(--line);
  color: #c6d5e4;
}

.exam-example strong {
  color: var(--cyan);
}

.management-study,
.industry-study,
.self-check {
  margin-top: 18px;
  padding: clamp(21px, 3vw, 30px);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--bg-raised);
}

.management-flow {
  display: grid;
  margin: 20px 0 0;
  padding: 0;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  gap: 10px;
  list-style: none;
}

.management-flow li {
  min-width: 0;
  padding: 14px;
  border: 1px solid var(--line);
  border-radius: 11px;
  background: var(--surface);
}

.management-flow strong,
.management-flow span {
  display: block;
}

.management-flow strong {
  color: #b9dfff;
  font-size: 1.04rem;
}

.management-flow span {
  margin-top: 6px;
  color: var(--muted);
  font-size: .96rem;
}

.industry-study {
  display: grid;
  grid-template-columns: minmax(0, .8fr) minmax(0, 1.2fr);
  align-items: center;
  gap: 24px;
  background: linear-gradient(110deg, rgba(10, 132, 255, .08), transparent 60%), var(--bg-raised);
}

.industry-study h3 {
  margin-top: 5px;
}

.industry-example-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 9px;
}

.industry-example-grid > div {
  display: grid;
  padding: 13px;
  gap: 5px;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--surface);
}

.industry-example-grid strong {
  color: var(--cyan);
  font-size: 1.02rem;
}

.industry-example-grid span {
  color: var(--muted);
  font-size: .98rem; line-height: 1.7;
}

.self-check h3 {
  margin-bottom: 10px;
}

.self-check details {
  border-top: 1px solid var(--line);
}

.self-check summary {
  padding: 13px 24px 13px 0;
  color: #cbd8e6;
  font-size: 1.08rem; font-weight: 600;
  cursor: pointer;
}

.self-check details > p {
  margin: 0 0 14px;
  color: var(--muted);
  font-size: 1.04rem; line-height: 1.8;
}

@media (max-width: 900px) {
  .management-flow {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .industry-study {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 700px) {
  .exam-concepts {
    grid-template-columns: 1fr;
  }

  .landmark-note {
    grid-template-columns: 1fr;
  }

  .management-flow {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 420px) {
  .management-flow,
  .industry-example-grid {
    grid-template-columns: 1fr;
  }
}

.history-context,
.engineering-scope,
.role-comparison,
.materials-study,
.workshop-safety,
.source-panel {
  margin-top: 18px;
  padding: clamp(20px, 3.5vw, 32px);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--bg-raised);
}

.history-context {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  align-items: start;
  gap: 18px;
  border-color: rgba(0, 210, 255, .22);
  background: linear-gradient(105deg, rgba(0, 210, 255, .07), transparent 70%), var(--bg-raised);
}

.history-context-mark {
  padding: 6px 11px;
  border: 1px solid rgba(0, 210, 255, .25);
  border-radius: 999px;
  background: rgba(0, 210, 255, .07);
  color: var(--cyan);
  font-size: .95rem;
  font-weight: 700;
  white-space: nowrap;
}

.history-context h3,
.extension-heading h3,
.source-panel h3 {
  margin: 0;
  font-size: 1.08rem;
}

.history-context p,
.extension-heading > p:last-child,
.source-panel > p {
  margin: 8px 0 0;
  color: var(--muted);
  font-size: 1.02rem; line-height: 1.8;
}

.extension-heading {
  max-width: 820px;
}

.extension-heading .card-label {
  margin: 0 0 5px;
}

.scope-grid,
.material-grid {
  display: grid;
  margin-top: 20px;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 11px;
}

.scope-grid article,
.material-card,
.role-card {
  min-width: 0;
  padding: 17px;
  border: 1px solid var(--line);
  border-radius: 13px;
  background: var(--surface);
}

.scope-grid h4,
.role-card h4,
.material-card h4,
.property-panel h4 {
  margin: 0;
  color: #dceaff;
  font-size: 1.22rem;
}

.scope-grid p,
.material-card p {
  margin: 7px 0 0;
  color: var(--muted);
  font-size: 1.04rem; line-height: 1.8;
}

.role-grid {
  display: grid;
  margin-top: 18px;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 13px;
}

.role-card-accent {
  border-color: rgba(0, 210, 255, .24);
  background: linear-gradient(145deg, rgba(0, 210, 255, .055), transparent 70%), var(--surface);
}

.role-card ul {
  display: grid;
  margin: 12px 0 0;
  padding-left: 19px;
  gap: 9px;
  color: var(--muted);
  font-size: 1.02rem; line-height: 1.8;
}

.role-note {
  margin: 14px 0 0;
  padding: 12px 15px;
  border-left: 2px solid var(--cyan);
  border-radius: 0 9px 9px 0;
  background: rgba(0, 210, 255, .045);
  color: var(--muted);
  font-size: .96rem; line-height: 1.7;
}

.role-note strong {
  color: var(--cyan);
}

.materials-study {
  background: linear-gradient(145deg, rgba(97, 216, 173, .04), transparent 65%), var(--bg-raised);
}

.material-grid {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.material-tag {
  display: inline-flex;
  margin-bottom: 10px;
  padding: 3px 9px;
  border: 1px solid rgba(0, 210, 255, .2);
  border-radius: 999px;
  background: rgba(0, 210, 255, .055);
  color: var(--cyan);
  font-size: .88rem; font-weight: 600;
  font-weight: 700;
}

.material-tag-green {
  border-color: rgba(97, 216, 173, .25);
  background: rgba(97, 216, 173, .06);
  color: var(--green);
}

.material-tag-violet {
  border-color: rgba(160, 133, 255, .25);
  background: rgba(160, 133, 255, .06);
  color: #c5b5ff;
}

.material-tag-amber {
  border-color: rgba(255, 198, 109, .25);
  background: rgba(255, 198, 109, .06);
  color: var(--amber);
}

.property-panel {
  margin-top: 15px;
  padding: 19px;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: rgba(12, 16, 22, .48);
}

.property-grid {
  display: grid;
  margin: 14px 0 0;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 9px;
}

.property-grid > div {
  min-width: 0;
  padding: 12px;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--surface);
}

.property-grid dt {
  color: #b9dfff;
  font-size: .98rem;
  font-weight: 700;
}

.property-grid dd {
  margin: 5px 0 0;
  color: var(--muted);
  font-size: .95rem;
}

.property-reminder {
  margin: 12px 0 0;
  color: var(--soft);
  font-size: .96rem;
}

.workshop-safety {
  border-color: rgba(255, 198, 109, .18);
  background: linear-gradient(150deg, rgba(255, 198, 109, .045), transparent 60%), var(--bg-raised);
}

.safety-list {
  display: grid;
  margin: 20px 0 0;
  padding: 0;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
  list-style: none;
  counter-reset: safety;
}

.safety-list li {
  position: relative;
  min-width: 0;
  padding: 14px 14px 14px 48px;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: rgba(18, 21, 27, .68);
  counter-increment: safety;
}

.safety-list li::before {
  position: absolute;
  top: 14px;
  left: 14px;
  display: grid;
  width: 24px;
  height: 24px;
  place-items: center;
  border: 1px solid rgba(255, 198, 109, .3);
  border-radius: 8px;
  background: rgba(255, 198, 109, .08);
  color: var(--amber);
  content: counter(safety, decimal-leading-zero);
  font-family: "Segoe UI", sans-serif;
  font-size: .62rem;
  font-weight: 700;
}

.safety-list strong,
.safety-list span {
  display: block;
}

.safety-list strong {
  color: #f1dfbf;
  font-size: 1.05rem;
}

.safety-list span {
  margin-top: 5px;
  color: var(--muted);
  font-size: .98rem; line-height: 1.7;
}

.safety-warning {
  margin: 15px 0 0;
  padding: 13px 15px;
  border: 1px solid rgba(255, 198, 109, .2);
  border-radius: 11px;
  background: rgba(255, 198, 109, .055);
  color: #d7c5a5;
  font-size: 1.02rem; line-height: 1.8;
}

.safety-warning strong {
  color: var(--amber);
}

.source-panel {
  background: var(--surface);
}

.source-panel ul {
  display: grid;
  margin: 14px 0 0;
  padding: 0;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 8px;
  list-style: none;
}

.source-panel li {
  min-width: 0;
}

.source-panel a, .source-panel .source-citation {
  display: block;
  height: 100%;
  padding: 10px 12px;
  border: 1px solid var(--line);
  border-radius: 9px;
  background: var(--bg-raised);
  color: #b9dfff;
  font-size: .98rem;
}

.source-panel a {
  text-decoration-color: rgba(185, 223, 255, .3);
  text-underline-offset: 3px;
}

.source-panel a:hover {
  border-color: rgba(0, 210, 255, .35);
  color: var(--cyan);
}

.source-panel a:focus-visible {
  outline: 3px solid var(--cyan);
  outline-offset: 3px;
}

.source-panel .source-note {
  margin-top: 12px;
  color: var(--soft);
  font-size: .95rem;
}

@media (max-width: 900px) {
  .scope-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .property-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 700px) {
  .history-context {
    grid-template-columns: 1fr;
    gap: 10px;
  }

  .scope-grid,
  .role-grid,
  .material-grid,
  .safety-list,
  .source-panel ul {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 420px) {
  .property-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 1250px) {
  .header-inner {
    gap: 16px;
  }

  .main-nav {
    min-width: 0;
    flex: 1 1 auto;
    justify-content: flex-start;
    gap: 14px;
    overflow-x: auto;
    scrollbar-width: none;
  }

  .main-nav::-webkit-scrollbar {
    display: none;
  }

  .main-nav a {
    flex: 0 0 auto;
    white-space: nowrap;
  }
}

@media (min-width: 1600px) {
  :root {
    --content: 1360px;
  }

  .source-panel a {
    min-height: 48px;
    display: flex;
    align-items: center;
    font-size: 1.02rem;
  }
}

.activity-section {
  position: relative;
}

.simulation-card {
  overflow: hidden;
  margin-top: 18px;
  padding: clamp(20px, 3.5vw, 34px);
  border: 1px solid var(--line);
  border-radius: 20px;
  background:
    radial-gradient(ellipse at 0 0, rgba(0, 210, 255, .09), transparent 42%),
    var(--bg-raised);
  box-shadow: 0 18px 50px rgba(0, 0, 0, .15);
}

.simulation-heading {
  display: flex;
  align-items: flex-start;
  gap: 16px;
}

.simulation-heading h3 {
  margin: 0;
  font-size: clamp(1.08rem, 2vw, 1.38rem);
}

.simulation-heading > div > p:last-child {
  margin: 5px 0 0;
  color: var(--muted);
  font-size: 1.05rem; line-height: 1.8;
}

.simulation-heading .card-label {
  margin: 0 0 4px;
  color: var(--cyan);
  font-size: .92rem; font-weight: 600;
  font-weight: 700;
}

.activity-symbol {
  display: grid;
  width: 48px;
  height: 48px;
  flex: 0 0 auto;
  place-items: center;
  border: 1px solid rgba(0, 210, 255, .3);
  border-radius: 15px;
  background: rgba(0, 210, 255, .08);
  color: var(--cyan);
  font-size: .78rem;
  font-weight: 700;
}

.activity-symbol-violet {
  border-color: rgba(160, 133, 255, .32);
  background: rgba(160, 133, 255, .1);
  color: #c5b5ff;
  font-size: 1.2rem;
}

.simulation-grid {
  display: grid;
  margin-top: 26px;
  grid-template-columns: minmax(0, .8fr) minmax(0, 1.2fr);
  gap: 20px;
}

.sim-controls,
.sim-results {
  min-width: 0;
  padding: 20px;
  border: 1px solid var(--line);
  border-radius: 15px;
  background: rgba(12, 16, 22, .55);
}

.sim-controls {
  display: grid;
  align-content: start;
  gap: 20px;
}

.sim-control {
  display: grid;
  gap: 10px;
  color: #dce7f3;
  font-size: 1.05rem;
  font-weight: 600;
}

.sim-control > span:first-child {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
}

.sim-control output {
  display: grid;
  width: 29px;
  height: 29px;
  flex: 0 0 auto;
  place-items: center;
  border: 1px solid rgba(0, 210, 255, .22);
  border-radius: 9px;
  background: rgba(0, 210, 255, .08);
  color: var(--cyan);
  font-variant-numeric: tabular-nums;
}

.sim-control input {
  width: 100%;
  margin: 0;
  accent-color: var(--cyan);
  cursor: pointer;
}

.sim-control input:focus-visible,
.quiz-option:focus-visible,
.quiz-next:focus-visible {
  outline: 3px solid var(--cyan);
  outline-offset: 3px;
}

.range-ends {
  display: flex;
  justify-content: space-between;
  color: var(--soft);
  font-size: .9rem;
  font-weight: 400;
}

.sim-note {
  margin: 0;
  padding-top: 14px;
  border-top: 1px solid var(--line);
  color: var(--soft);
  font-size: .95rem;
}

.sim-results h4, .quiz-area h4 {
  margin: 0;
  font-size: 1.25rem;
}

.sim-results-list {
  display: grid;
  margin: 15px 0 0;
  padding: 0;
  gap: 15px;
  list-style: none;
}

.sim-result-heading {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 8px;
}

.sim-result-heading strong {
  color: #dce7f3;
  font-size: 1.08rem;
}

.sim-result-heading > span {
  flex: 0 0 auto;
  color: var(--cyan);
  font-size: .96rem;
  font-variant-numeric: tabular-nums;
}

.sim-score-track {
  overflow: hidden;
  height: 7px;
  margin-top: 7px;
  border-radius: 99px;
  background: rgba(255, 255, 255, .08);
}

.sim-score-track > span {
  display: block;
  height: 100%;
  border-radius: inherit;
  background: linear-gradient(90deg, var(--blue), var(--cyan));
  transition: width .35s ease;
}

.sim-result-item:first-child .sim-score-track > span {
  background: linear-gradient(90deg, #00a8ff, #61d8ad);
}

.sim-result-item > p {
  margin: 5px 0 0;
  color: var(--soft);
  font-size: 1.02rem; line-height: 1.8;
}

.sim-recommendation {
  margin: 17px 0 0;
  padding: 12px 14px;
  border: 1px solid rgba(97, 216, 173, .18);
  border-radius: 11px;
  background: rgba(97, 216, 173, .055);
  color: #b9f0d9;
  font-size: 1.08rem; line-height: 1.85;
}

.quiz-card {
  background:
    radial-gradient(ellipse at 100% 0, rgba(160, 133, 255, .1), transparent 42%),
    var(--bg-raised);
}

.quiz-area {
  margin-top: 24px;
  padding: clamp(18px, 3vw, 26px);
  border: 1px solid var(--line);
  border-radius: 15px;
  background: rgba(12, 16, 22, .55);
}

.quiz-meta {
  display: flex;
  margin-bottom: 15px;
  justify-content: space-between;
  gap: 10px;
  color: var(--cyan);
  font-size: 1.02rem; font-weight: 700;
  font-weight: 700;
}

.quiz-meta span:last-child {
  color: var(--muted);
}

.quiz-area h4 {
  max-width: 780px;
  line-height: 1.8;
}

.quiz-options {
  display: grid;
  margin-top: 16px;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 10px;
}

.quiz-option {
  min-height: 76px;
  padding: 13px;
  border: 1px solid var(--line);
  border-radius: 11px;
  background: var(--surface);
  color: #cbd8e6;
  font: inherit;
  font-size: 1.06rem; padding: 14px 18px; line-height: 1.7;
  line-height: 1.65;
  text-align: left;
  cursor: pointer;
  transition: border-color .2s ease, background .2s ease, transform .2s ease;
}

.quiz-option:not(:disabled):hover {
  transform: translateY(-2px);
  border-color: rgba(0, 210, 255, .45);
  background: rgba(0, 210, 255, .06);
}

.quiz-option:disabled {
  cursor: default;
}

.quiz-option.is-correct {
  border-color: rgba(97, 216, 173, .55);
  background: rgba(97, 216, 173, .1);
  color: #b9f0d9;
}

.quiz-option.is-incorrect {
  border-color: rgba(255, 133, 139, .42);
  background: rgba(255, 133, 139, .07);
  color: #ffc0c3;
}

.quiz-feedback {
  min-height: 1.8em;
  margin: 15px 0 0;
  color: var(--muted);
  font-size: 1.08rem; line-height: 1.8;
}

.quiz-next {
  margin-top: 13px;
  cursor: pointer;
}

.quiz-next[hidden] {
  display: none;
}

@media (max-width: 900px) {
  .simulation-grid {
    grid-template-columns: 1fr;
  }

  .sim-controls {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .sim-note {
    grid-column: 1 / -1;
  }
}

@media (max-width: 700px) {
  .sim-controls {
    grid-template-columns: 1fr;
  }

  .quiz-options {
    grid-template-columns: 1fr;
  }

  .quiz-option {
    min-height: 54px;
  }
}

@media (max-width: 420px) {
  .simulation-heading {
    gap: 11px;
  }

  .activity-symbol {
    width: 40px;
    height: 40px;
    border-radius: 12px;
  }

  .sim-controls,
  .sim-results {
    padding: 16px;
  }
}