:root {
  --paper: #f4f1eb;
  --paper-2: #fbfaf7;
  --surface: rgba(255, 255, 255, 0.76);
  --surface-solid: #ffffff;
  --ink: #191f28;
  --sub: #4e5968;
  --faint: #8b95a1;
  --hair: #dfe3e6;
  --grid: rgba(25, 31, 40, 0.055);
  --copper: #c4732a;
  --copper-deep: #8f4f18;
  --copper-soft: #f0dcc7;
  --resin: #233247;
  --resin-2: #34465f;
  --chem: #2e9e9a;
  --chem-soft: #d7efec;
  --danger: #d22c2c;
  --danger-soft: #f7dfdc;
  --green: #347b5e;
  --yellow: #e3ae35;
  --mask-color: #2f805f;
  --gold: #d2a63f;
  --shadow: 0 24px 64px rgba(28, 35, 45, 0.10);
  --font: "Pretendard Variable", Pretendard, -apple-system, BlinkMacSystemFont, "Apple SD Gothic Neo", "Noto Sans KR", sans-serif;
  --mono: "SFMono-Regular", Menlo, Monaco, Consolas, monospace;
}

[data-theme="dark"] {
  --paper: #11161d;
  --paper-2: #171d25;
  --surface: rgba(27, 34, 44, 0.82);
  --surface-solid: #1c232d;
  --ink: #f2f4f6;
  --sub: #c4cad1;
  --faint: #89939f;
  --hair: #343e49;
  --grid: rgba(255, 255, 255, 0.035);
  --copper: #df8b3f;
  --copper-deep: #f1ae70;
  --copper-soft: #4a3223;
  --resin: #526d8d;
  --resin-2: #3a4c62;
  --chem: #61c9c2;
  --chem-soft: #203e40;
  --danger: #ff6f6f;
  --danger-soft: #4b292b;
  --green: #68b892;
  --yellow: #f0c45f;
  --mask-color: #4ea37d;
  --gold: #e5bd58;
  --shadow: 0 28px 80px rgba(0, 0, 0, 0.32);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-width: 320px;
  min-height: 100vh;
  color: var(--ink);
  background:
    linear-gradient(var(--grid) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid) 1px, transparent 1px),
    var(--paper);
  background-size: 24px 24px;
  font-family: var(--font);
  line-height: 1.68;
  -webkit-font-smoothing: antialiased;
}

button {
  color: inherit;
  font: inherit;
}

button:focus-visible {
  outline: 3px solid color-mix(in srgb, var(--chem) 55%, transparent);
  outline-offset: 3px;
}

.app-shell {
  width: min(1600px, calc(100vw - 48px));
  margin: 0 auto;
  padding: 28px 0 64px;
}

.topbar {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  align-items: end;
  gap: 28px;
  padding: 4px 2px 22px;
  border-bottom: 1px solid var(--hair);
}

.eyebrow,
.stage-tag,
.micro-label,
.panel-label,
.rail-number {
  font-family: var(--mono);
  letter-spacing: 0.13em;
  text-transform: uppercase;
}

.eyebrow {
  margin: 0 0 5px;
  color: var(--copper-deep);
  font-size: 11px;
  font-weight: 800;
}

.brand-title {
  display: flex;
  align-items: baseline;
  gap: 14px;
  margin: 0;
  font-size: clamp(25px, 2.5vw, 39px);
  line-height: 1.12;
  letter-spacing: -0.045em;
  font-weight: 820;
}

.brand-title span {
  color: var(--faint);
  font-size: 0.4em;
  font-family: var(--mono);
  letter-spacing: 0.08em;
}

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

.control-button,
.segmented button,
.autoplay-button,
.step-button,
.tab-button,
.quiz-option {
  border: 1px solid var(--hair);
  background: var(--surface);
  cursor: pointer;
  transition: transform 180ms ease, border-color 180ms ease, background 180ms ease, color 180ms ease;
}

.control-button:hover,
.segmented button:hover,
.autoplay-button:hover,
.step-button:hover,
.tab-button:hover,
.quiz-option:hover {
  border-color: color-mix(in srgb, var(--copper) 55%, var(--hair));
}

.control-button:active,
.step-button:active,
.quiz-option:active {
  transform: translateY(1px);
}

.control-button {
  min-width: 46px;
  height: 46px;
  padding: 0 14px;
  border-radius: 6px;
  font-weight: 760;
}

.position-bar {
  position: sticky;
  z-index: 30;
  top: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  align-items: center;
  gap: 18px;
  min-height: 58px;
  margin: 16px 0 8px;
  padding: 11px 16px 15px;
  border: 1px solid var(--hair);
  background: color-mix(in srgb, var(--surface-solid) 94%, transparent);
  box-shadow: 0 10px 30px rgba(26, 32, 42, 0.08);
  backdrop-filter: blur(18px);
}

.position-copy,
.position-neighbors {
  display: flex;
  align-items: center;
  gap: 10px;
}

.position-copy {
  min-width: 0;
  font-size: 14px;
}

.position-copy strong {
  overflow: hidden;
  font-size: 16px;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.position-copy .position-substage {
  color: var(--accent);
}

.position-count {
  color: var(--paper-2);
  padding: 3px 8px;
  background: var(--ink);
  border-radius: 3px;
  font-family: var(--mono);
  font-size: 10px;
  font-weight: 800;
  letter-spacing: 0.07em;
  white-space: nowrap;
}

.position-divider {
  color: var(--faint);
}

.position-phase {
  color: var(--copper-deep);
  font-weight: 760;
  white-space: nowrap;
}

.position-neighbors {
  color: var(--faint);
  font-size: 11px;
}

.position-neighbors span {
  display: flex;
  gap: 5px;
}

.position-neighbors b {
  color: var(--sub);
}

.position-progress {
  position: absolute;
  right: 0;
  bottom: 0;
  left: 0;
  height: 4px;
  overflow: hidden;
  background: var(--hair);
}

.position-progress i {
  display: block;
  height: 100%;
  background: var(--copper);
  transition: width 320ms ease;
}

.process-rail {
  position: sticky;
  z-index: 25;
  top: 58px;
  display: grid;
  grid-template-columns: repeat(6, minmax(0, 1fr));
  gap: 8px;
  margin: 0 0 14px;
  padding: 7px 0 9px;
  overflow-x: auto;
  background: color-mix(in srgb, var(--paper) 94%, transparent);
  backdrop-filter: blur(16px);
  scrollbar-width: thin;
}

.rail-item {
  position: relative;
  display: grid;
  grid-template-rows: auto auto 1fr;
  gap: 2px;
  min-width: 0;
  min-height: 70px;
  padding: 9px 12px 8px;
  color: var(--faint);
  border: 1px solid var(--hair);
  border-top: 3px solid var(--hair);
  border-radius: 4px;
  background: color-mix(in srgb, var(--surface-solid) 72%, transparent);
  text-align: left;
  cursor: pointer;
  transition: color 180ms ease, background 180ms ease, border-color 180ms ease, transform 180ms ease;
}

.rail-item::before {
  content: none;
}

.rail-item:hover {
  color: var(--ink);
  border-color: color-mix(in srgb, var(--copper) 45%, var(--hair));
  transform: translateY(-2px);
}

.rail-item.phase-a { border-top-color: #8793a2; }
.rail-item.phase-b { border-top-color: var(--copper); }
.rail-item.phase-c { border-top-color: var(--chem); }
.rail-item.phase-d { border-top-color: var(--green); }

.rail-item.is-active {
  color: var(--paper-2);
  background: var(--ink);
  border-color: var(--ink);
  border-top-color: var(--copper);
  box-shadow: 0 8px 20px rgba(25, 31, 40, 0.18);
}

.rail-item.is-active .rail-number,
.rail-item.is-active .rail-purpose {
  color: color-mix(in srgb, var(--paper-2) 66%, transparent);
}

.rail-item.is-active::after {
  content: "현재";
  position: absolute;
  top: 7px;
  right: 7px;
  color: var(--paper-2);
  font-size: 8px;
  font-weight: 800;
  opacity: 0.72;
}

.rail-number {
  color: var(--faint);
  font-size: 10px;
  font-weight: 800;
}

.rail-name {
  color: inherit;
  font-size: 14px;
  font-weight: 800;
  line-height: 1.35;
}

.rail-purpose {
  align-self: end;
  color: var(--faint);
  font-size: 10px;
  line-height: 1.25;
}

.hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.5fr) minmax(330px, 0.72fr);
  min-height: 660px;
  border: 1px solid var(--hair);
  background: var(--surface);
  box-shadow: var(--shadow);
  backdrop-filter: blur(18px);
}

.visual-zone {
  display: flex;
  flex-direction: column;
  min-width: 0;
  border-right: 1px solid var(--hair);
}

.stage-header {
  display: grid;
  grid-template-columns: auto 1fr auto;
  align-items: start;
  gap: 18px;
  padding: 24px 28px 18px;
  border-bottom: 1px solid var(--hair);
}

.stage-number {
  display: grid;
  place-items: center;
  width: 58px;
  height: 58px;
  color: var(--paper-2);
  background: var(--ink);
  border-radius: 50%;
  font-family: var(--mono);
  font-size: 16px;
  font-weight: 800;
}

.stage-tag {
  margin: 0 0 4px;
  color: var(--copper-deep);
  font-size: 10px;
  font-weight: 800;
}

.stage-title {
  display: flex;
  align-items: baseline;
  flex-wrap: wrap;
  gap: 10px;
  margin: 0;
  font-size: clamp(27px, 3vw, 44px);
  line-height: 1.05;
  letter-spacing: -0.055em;
}

.stage-title span {
  color: var(--copper-deep);
  font-size: 0.38em;
  letter-spacing: -0.02em;
}

.stage-change {
  max-width: 330px;
  margin: 0;
  color: var(--sub);
  font-size: 14px;
  line-height: 1.65;
  text-align: right;
  text-wrap: pretty;
}

.subprocess-rail {
  display: grid;
  grid-template-columns: 190px minmax(0, 1fr);
  gap: 14px;
  padding: 13px 18px;
  border-bottom: 1px solid var(--hair);
  background: color-mix(in srgb, var(--chem-soft) 42%, var(--paper-2));
}

.subprocess-intro {
  display: grid;
  align-content: center;
  gap: 3px;
  padding-right: 14px;
  border-right: 1px solid color-mix(in srgb, var(--chem) 28%, var(--hair));
}

.subprocess-intro strong {
  font-size: 12px;
  line-height: 1.4;
}

.subprocess-buttons {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 6px;
}

.subprocess-buttons button {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 0 7px;
  min-height: 53px;
  padding: 7px 9px;
  color: var(--sub);
  border: 1px solid color-mix(in srgb, var(--chem) 24%, var(--hair));
  border-radius: 4px;
  background: color-mix(in srgb, var(--surface-solid) 78%, transparent);
  text-align: left;
  cursor: pointer;
}

.subprocess-buttons button:hover {
  border-color: var(--chem);
}

.subprocess-buttons button.active {
  color: var(--paper-2);
  border-color: var(--resin);
  background: var(--resin);
  box-shadow: 0 6px 16px rgba(23, 39, 54, 0.16);
}

.subprocess-buttons span {
  grid-row: 1 / 3;
  color: var(--chem);
  font-family: var(--mono);
  font-size: 9px;
  font-weight: 800;
}

.subprocess-buttons button.active span,
.subprocess-buttons button.active small {
  color: color-mix(in srgb, var(--paper-2) 68%, transparent);
}

.subprocess-buttons strong {
  font-size: 11px;
  line-height: 1.25;
}

.subprocess-buttons small {
  color: var(--faint);
  font-size: 8px;
  line-height: 1.25;
}

.microscope {
  position: relative;
  display: grid;
  place-items: center;
  min-height: 440px;
  padding: 20px 24px 8px;
  overflow: hidden;
  background:
    radial-gradient(circle at 50% 42%, color-mix(in srgb, var(--copper) 8%, transparent), transparent 38%),
    linear-gradient(transparent 49.75%, color-mix(in srgb, var(--ink) 7%, transparent) 50%, transparent 50.25%),
    linear-gradient(90deg, transparent 49.75%, color-mix(in srgb, var(--ink) 7%, transparent) 50%, transparent 50.25%);
  flex: 1 1 auto;
}

.microscope::before,
.microscope::after {
  content: "";
  position: absolute;
  width: 38px;
  height: 38px;
  border-color: color-mix(in srgb, var(--ink) 28%, transparent);
  pointer-events: none;
}

.microscope::before {
  top: 18px;
  left: 22px;
  border-top: 1px solid;
  border-left: 1px solid;
}

.microscope::after {
  right: 22px;
  bottom: 18px;
  border-right: 1px solid;
  border-bottom: 1px solid;
}

.pcb-svg {
  width: min(100%, 850px);
  height: auto;
  overflow: visible;
}

.pcb-svg text {
  font-family: var(--font);
}

.pcb-svg .label {
  fill: var(--sub);
  font-size: 13px;
  font-weight: 720;
}

.pcb-svg .micro {
  fill: var(--faint);
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: 0.08em;
}

.pcb-svg .leader {
  fill: none;
  stroke: var(--faint);
  stroke-width: 1;
  stroke-dasharray: 4 4;
}

.pcb-svg .board-body {
  fill: var(--resin);
}

.pcb-svg .board-edge {
  fill: none;
  stroke: color-mix(in srgb, var(--ink) 30%, transparent);
  stroke-width: 1.25;
}

.pcb-svg .copper-layer,
.pcb-svg .pad {
  fill: var(--copper);
}

.pcb-svg .prepreg {
  fill: color-mix(in srgb, var(--resin) 72%, var(--paper-2));
  stroke: color-mix(in srgb, var(--resin) 60%, var(--paper-2));
}

.pcb-svg .hole {
  fill: var(--paper-2);
  stroke: color-mix(in srgb, var(--ink) 20%, transparent);
  stroke-width: 1;
}

.pcb-svg .chem-stroke {
  fill: none;
  stroke: var(--chem);
  stroke-width: 3;
  stroke-linecap: round;
  stroke-dasharray: 7 8;
  animation: wash 1.5s linear infinite;
}

.pcb-svg .seed {
  fill: var(--copper);
  opacity: 0.92;
}

.pcb-svg .plated {
  fill: var(--copper);
}

.pcb-svg .fill-material {
  fill: color-mix(in srgb, var(--copper) 68%, var(--resin));
}

.pcb-svg .danger-mark {
  fill: var(--danger);
  stroke: var(--danger);
}

.pcb-svg .danger-line {
  fill: none;
  stroke: var(--danger);
  stroke-width: 2.4;
  stroke-linecap: round;
}

.pcb-svg .pulse-ring {
  fill: none;
  stroke: var(--copper);
  stroke-width: 2;
  transform-origin: center;
  animation: pulse-ring 2s ease-out infinite;
}

.pcb-svg .press-arrow {
  fill: var(--ink);
  animation: press 1.8s ease-in-out infinite;
}

.pcb-svg .drill-bit {
  fill: var(--ink);
  animation: drill 1.4s ease-in-out infinite;
}

.pcb-svg .particle {
  fill: var(--chem);
  animation: float-away 1.7s ease-out infinite;
}

.pcb-svg .scan-line {
  animation: scanner 3.4s ease-in-out infinite alternate;
}

.pcb-svg .test-flow {
  animation: test-current 1.2s linear infinite;
}

@keyframes wash {
  to { stroke-dashoffset: -30; }
}

@keyframes pulse-ring {
  0% { opacity: 0.75; transform: scale(0.96); }
  70%, 100% { opacity: 0; transform: scale(1.12); }
}

@keyframes press {
  0%, 100% { transform: translateY(-7px); }
  50% { transform: translateY(4px); }
}

@keyframes drill {
  0%, 100% { transform: translateY(-9px); }
  50% { transform: translateY(8px); }
}

@keyframes float-away {
  0% { opacity: 0; transform: translate(0, 0); }
  25% { opacity: 1; }
  100% { opacity: 0; transform: translate(18px, -24px); }
}

@keyframes scanner {
  from { transform: translateX(0); }
  to { transform: translateX(515px); }
}

@keyframes test-current {
  to { stroke-dashoffset: -26; }
}

.visual-footer {
  display: grid;
  grid-template-columns: 1fr;
  gap: 12px;
  padding: 12px 20px 16px;
  border-top: 1px solid var(--hair);
}

.legend {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  color: var(--sub);
  font-size: 11px;
}

.legend-item {
  display: flex;
  align-items: center;
  gap: 6px;
}

.legend-swatch {
  width: 22px;
  height: 7px;
  background: var(--ink);
}

.legend-swatch.copper { background: var(--copper); }
.legend-swatch.resin { background: var(--resin); }
.legend-swatch.chem { background: var(--chem); }
.legend-swatch.danger { background: var(--danger); }

.playback {
  display: grid;
  grid-template-columns: minmax(120px, 0.9fr) minmax(250px, 1.35fr) minmax(120px, 0.9fr);
  gap: 10px;
  width: 100%;
}

.jump-button {
  display: grid;
  gap: 1px;
  min-width: 0;
  min-height: 60px;
  padding: 10px 13px;
  color: var(--sub);
  border: 1px solid var(--hair);
  border-radius: 4px;
  background: var(--surface-solid);
  cursor: pointer;
  transition: border-color 180ms ease, transform 180ms ease;
}

.jump-button:hover {
  border-color: var(--copper);
  transform: translateY(-1px);
}

.jump-button.previous {
  text-align: left;
}

.jump-button.next {
  text-align: right;
}

.jump-button span {
  color: var(--faint);
  font-size: 10px;
}

.jump-button strong {
  font-size: 12px;
  line-height: 1.25;
}

.autoplay-button {
  display: grid;
  grid-template-columns: 38px 1fr;
  align-items: center;
  gap: 11px;
  min-height: 60px;
  padding: 8px 14px;
  color: var(--paper-2);
  border-color: var(--ink);
  border-radius: 4px;
  background: var(--ink);
  text-align: left;
}

.autoplay-button:hover {
  border-color: var(--copper);
  transform: translateY(-1px);
}

.autoplay-button.is-playing {
  border-color: var(--copper);
  background: var(--copper-deep);
}

.autoplay-symbol {
  display: grid;
  place-items: center;
  width: 34px;
  height: 34px;
  color: var(--paper-2);
  border: 1px solid color-mix(in srgb, var(--paper-2) 32%, transparent);
  background: color-mix(in srgb, var(--paper-2) 10%, transparent);
  font-size: 13px;
  font-weight: 800;
}

.autoplay-copy {
  display: grid;
  gap: 3px;
}

.autoplay-copy strong {
  font-size: 13px;
  line-height: 1.25;
}

.autoplay-copy small {
  color: color-mix(in srgb, var(--paper-2) 62%, transparent);
  font-size: 9px;
  line-height: 1.35;
}

.step-button {
  display: grid;
  place-items: center;
  width: 42px;
  height: 42px;
  border-radius: 50%;
  font-weight: 800;
}

.step-button.primary {
  color: var(--paper-2);
  background: var(--ink);
  border-color: var(--ink);
}

.stage-dots {
  display: flex;
  gap: 6px;
}

.stage-dot {
  width: 7px;
  height: 7px;
  padding: 0;
  border: 0;
  border-radius: 50%;
  background: var(--hair);
  cursor: pointer;
}

.stage-dot.active {
  width: 24px;
  border-radius: 99px;
  background: var(--copper);
}

.explain-zone {
  display: grid;
  grid-template-rows: auto 1fr;
  min-width: 0;
  background: color-mix(in srgb, var(--paper-2) 88%, transparent);
}

.mode-strip {
  display: grid;
  gap: 10px;
  padding: 14px 16px;
  border-bottom: 1px solid var(--hair);
}

.mode-row {
  display: grid;
  grid-template-columns: 104px minmax(0, 1fr);
  align-items: center;
  gap: 10px;
}

.mode-heading {
  display: grid;
  gap: 2px;
}

.mode-heading strong {
  color: var(--ink);
  font-size: 12px;
}

.mode-heading span {
  color: var(--faint);
  font-size: 8px;
  line-height: 1.3;
}

.mode-summary {
  margin: 1px 0 0;
  padding-top: 9px;
  color: var(--faint);
  border-top: 1px solid var(--hair);
  font-size: 9px;
  line-height: 1.45;
}

.mode-summary strong {
  color: var(--sub);
}

.segmented {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 3px;
  padding: 3px;
  background: var(--paper);
  border: 1px solid var(--hair);
  border-radius: 7px;
}

.segmented button {
  min-height: 36px;
  padding: 6px 8px;
  border-color: transparent;
  border-radius: 4px;
  color: var(--faint);
  background: transparent;
  font-size: 11px;
  font-weight: 760;
}

.segmented button.active {
  color: var(--ink);
  background: var(--surface-solid);
  border-color: var(--hair);
  box-shadow: 0 3px 12px rgba(23, 31, 42, 0.07);
}

.segmented button.danger.active {
  color: var(--danger);
  background: var(--danger-soft);
  border-color: color-mix(in srgb, var(--danger) 25%, var(--hair));
}

.explain-stack {
  display: grid;
  align-content: start;
}

.definition-block {
  padding: 26px 24px 22px;
  border-bottom: 1px solid var(--hair);
}

.definition-block h2 {
  margin: 3px 0 10px;
  font-size: 23px;
  line-height: 1.35;
  letter-spacing: -0.035em;
  text-wrap: pretty;
}

.definition-block p {
  margin: 0;
  color: var(--sub);
  font-size: 14px;
}

.micro-label,
.panel-label {
  color: var(--faint);
  font-size: 9px;
  font-weight: 800;
}

.why-chain {
  display: grid;
  gap: 0;
  padding: 22px 24px;
  border-bottom: 1px solid var(--hair);
}

.why-step {
  position: relative;
  display: grid;
  grid-template-columns: 24px 1fr;
  gap: 10px;
  min-height: 58px;
  color: var(--sub);
  font-size: 13px;
  line-height: 1.55;
}

.why-step:not(:last-child)::after {
  content: "";
  position: absolute;
  top: 23px;
  left: 11px;
  width: 1px;
  height: 35px;
  background: var(--hair);
}

.why-index {
  position: relative;
  z-index: 1;
  display: grid;
  place-items: center;
  width: 23px;
  height: 23px;
  color: var(--paper-2);
  background: var(--copper);
  border-radius: 50%;
  font-family: var(--mono);
  font-size: 9px;
  font-weight: 800;
}

.analogy-block,
.risk-block {
  padding: 20px 24px;
  border-bottom: 1px solid var(--hair);
}

.analogy-title {
  display: flex;
  align-items: center;
  gap: 9px;
  margin: 6px 0 7px;
  color: var(--copper-deep);
  font-size: 15px;
  font-weight: 800;
}

.analogy-title::before {
  content: "≈";
  font-family: Georgia, serif;
  font-size: 23px;
  font-weight: 400;
}

.analogy-block p,
.risk-block p {
  margin: 0;
  color: var(--sub);
  font-size: 13px;
  line-height: 1.7;
}

.risk-block {
  background: color-mix(in srgb, var(--danger-soft) 45%, transparent);
}

.risk-block .panel-label {
  color: var(--danger);
}

.risk-block p {
  margin-top: 7px;
  color: color-mix(in srgb, var(--danger) 70%, var(--ink));
  font-weight: 730;
}

.knowledge-dock {
  margin-top: 18px;
  border: 1px solid var(--hair);
  background: var(--surface);
  box-shadow: 0 16px 40px rgba(28, 35, 45, 0.07);
  backdrop-filter: blur(18px);
}

.tab-list {
  display: grid;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  border-bottom: 1px solid var(--hair);
}

.tab-button {
  min-width: 0;
  height: 48px;
  padding: 0 10px;
  color: var(--faint);
  background: transparent;
  border: 0;
  border-right: 1px solid var(--hair);
  font-size: 12px;
  font-weight: 760;
}

.tab-button.active {
  color: var(--ink);
  background: var(--surface-solid);
  box-shadow: inset 0 -3px 0 var(--copper);
}

.tab-panel {
  min-height: 0;
  padding: 18px 20px 20px;
}

.flow-panel {
  display: grid;
  gap: 12px;
}

.flow-heading {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 16px;
}

.flow-heading div {
  display: grid;
  gap: 3px;
}

.flow-heading strong {
  color: var(--ink);
  font-size: 14px;
}

.flow-heading > span {
  color: var(--faint);
  font-size: 10px;
  white-space: nowrap;
}

.flow-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 8px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.flow-step {
  display: grid;
  grid-template-columns: 30px minmax(0, 1fr);
  align-items: center;
  gap: 10px;
  min-height: 72px;
  padding: 10px 12px;
  border: 1px solid var(--hair);
  border-top: 2px solid color-mix(in srgb, var(--copper) 70%, var(--hair));
  background: color-mix(in srgb, var(--paper-2) 72%, transparent);
}

.flow-index {
  display: grid;
  place-items: center;
  width: 28px;
  height: 28px;
  color: var(--paper-2);
  background: var(--ink);
  font-family: var(--mono);
  font-size: 9px;
  font-weight: 800;
}

.flow-copy {
  display: grid;
  gap: 3px;
  min-width: 0;
}

.flow-name {
  display: block;
  font-size: 13px;
  font-weight: 780;
  line-height: 1.35;
}

.flow-copy small {
  color: var(--faint);
  font-size: 9px;
}

.control-grid,
.ceo-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 18px;
}

.control-card,
.ceo-card {
  position: relative;
  min-height: 154px;
  padding: 22px 22px 20px;
  border-top: 3px solid var(--copper);
  border-right: 1px solid var(--hair);
  border-bottom: 1px solid var(--hair);
  border-left: 1px solid var(--hair);
  background: color-mix(in srgb, var(--surface-solid) 78%, transparent);
}

.control-card h3,
.ceo-card h3 {
  margin: 0 0 12px;
  font-size: 14px;
}

.control-card p,
.ceo-card p {
  margin: 0;
  color: var(--sub);
  font-size: 13px;
  line-height: 1.7;
}

.ceo-card {
  border-top-color: var(--ink);
}

.ceo-card .q-mark {
  position: absolute;
  top: 16px;
  right: 18px;
  color: var(--copper);
  font-family: Georgia, serif;
  font-size: 32px;
}

.defect-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 13px;
}

.defect-table th {
  padding: 10px 14px;
  color: var(--faint);
  border-bottom: 1px solid var(--hair);
  font-family: var(--mono);
  font-size: 9px;
  letter-spacing: 0.1em;
  text-align: left;
}

.defect-table td {
  padding: 15px 14px;
  border-bottom: 1px solid var(--hair);
  color: var(--sub);
  vertical-align: top;
}

.defect-table tr:last-child td {
  border-bottom: 0;
}

.defect-table td:nth-child(2) {
  color: var(--danger);
  font-weight: 760;
}

.arrow-cell {
  width: 36px;
  color: var(--faint) !important;
  text-align: center;
}

.quiz-wrap {
  display: grid;
  grid-template-columns: minmax(0, 0.72fr) minmax(360px, 1.28fr);
  gap: 28px;
  align-items: stretch;
}

.quiz-question {
  padding: 24px;
  color: var(--paper-2);
  background: var(--ink);
}

.quiz-question .panel-label {
  color: color-mix(in srgb, var(--paper-2) 55%, transparent);
}

.quiz-question h3 {
  margin: 16px 0 0;
  font-size: 22px;
  line-height: 1.5;
  letter-spacing: -0.035em;
}

.quiz-options {
  display: grid;
  gap: 9px;
}

.quiz-option {
  min-height: 52px;
  padding: 13px 16px;
  border-radius: 4px;
  color: var(--sub);
  text-align: left;
}

.quiz-option.correct {
  color: var(--green);
  border-color: var(--green);
  background: color-mix(in srgb, var(--green) 11%, var(--surface-solid));
}

.quiz-option.wrong {
  color: var(--danger);
  border-color: var(--danger);
  background: color-mix(in srgb, var(--danger) 9%, var(--surface-solid));
}

.quiz-feedback {
  margin: 12px 0 0;
  padding: 12px 14px;
  color: var(--sub);
  border-left: 3px solid var(--copper);
  background: var(--paper-2);
  font-size: 12px;
}

.source-note {
  display: flex;
  justify-content: space-between;
  gap: 24px;
  margin-top: 16px;
  padding: 0 2px;
  color: var(--faint);
  font-size: 10px;
}

.source-note strong {
  color: var(--sub);
}

@media (max-width: 1120px) {
  .app-shell {
    width: min(100% - 28px, 980px);
  }

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

  .process-rail {
    grid-template-columns: repeat(12, 104px);
  }

  .visual-zone {
    border-right: 0;
    border-bottom: 1px solid var(--hair);
  }

  .explain-zone {
    grid-template-columns: 240px 1fr;
    grid-template-rows: auto;
  }

  .mode-strip {
    grid-template-columns: 1fr;
    align-content: start;
    border-right: 1px solid var(--hair);
    border-bottom: 0;
  }

  .mode-row {
    grid-template-columns: 1fr;
    gap: 6px;
  }

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

  .definition-block,
  .why-chain,
  .analogy-block,
  .risk-block {
    border-right: 1px solid var(--hair);
  }

  .flow-grid {
    grid-template-columns: repeat(3, 1fr);
    gap: 10px;
  }

}

@media (max-width: 760px) {
  .app-shell {
    width: min(100% - 18px, 640px);
    padding-top: 14px;
  }

  .topbar {
    grid-template-columns: 1fr;
    gap: 14px;
  }

  .top-controls {
    justify-content: flex-start;
  }

  .brand-title {
    display: grid;
    gap: 2px;
  }

  .brand-title span {
    font-size: 0.46em;
  }

  .position-bar {
    grid-template-columns: 1fr;
    min-height: 54px;
    margin-top: 10px;
    padding: 10px 12px 14px;
  }

  .position-copy {
    gap: 7px;
    font-size: 12px;
  }

  .position-copy strong {
    font-size: 14px;
  }

  .position-neighbors {
    display: none;
  }

  .process-rail {
    top: 54px;
    grid-template-columns: repeat(12, 100px);
    padding-bottom: 7px;
  }

  .rail-item {
    min-height: 68px;
    padding: 7px 8px;
  }

  .stage-header {
    grid-template-columns: auto 1fr;
    padding: 18px;
  }

  .stage-number {
    width: 48px;
    height: 48px;
  }

  .stage-change {
    grid-column: 1 / -1;
    max-width: none;
    text-align: left;
  }

  .subprocess-rail {
    grid-template-columns: 1fr;
    gap: 8px;
    padding: 11px 12px;
  }

  .subprocess-intro {
    padding: 0 0 7px;
    border-right: 0;
    border-bottom: 1px solid color-mix(in srgb, var(--chem) 28%, var(--hair));
  }

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

  .microscope {
    min-height: 330px;
    padding: 10px;
  }

  .visual-footer {
    grid-template-columns: 1fr;
  }

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

  .jump-button {
    width: auto;
  }

  .autoplay-button {
    grid-column: 1 / -1;
    grid-row: 1;
  }

  .explain-zone {
    grid-template-columns: 1fr;
  }

  .mode-strip {
    grid-template-columns: 1fr;
    border-right: 0;
    border-bottom: 1px solid var(--hair);
  }

  .explain-stack {
    grid-template-columns: 1fr;
  }

  .definition-block,
  .why-chain,
  .analogy-block,
  .risk-block {
    border-right: 0;
  }

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

  .control-grid,
  .ceo-grid,
  .quiz-wrap {
    grid-template-columns: 1fr;
  }

  .tab-panel {
    padding: 14px 12px 16px;
  }

  .tab-button {
    height: 44px;
    padding: 0 5px;
    font-size: 11px;
  }

  .flow-heading {
    align-items: start;
  }

  .flow-heading > span {
    display: none;
  }

  .flow-step {
    min-height: 66px;
    padding: 8px 9px;
  }

  .defect-table thead {
    display: none;
  }

  .defect-table tr,
  .defect-table td {
    display: block;
  }

  .defect-table tr {
    padding: 12px 0;
    border-bottom: 1px solid var(--hair);
  }

  .defect-table td {
    padding: 4px 8px;
    border: 0;
  }

  .arrow-cell {
    display: none !important;
  }

  .source-note {
    flex-direction: column;
    gap: 6px;
  }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    scroll-behavior: auto !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

@media print {
  body {
    background: #fff;
  }

  .app-shell {
    width: 100%;
    padding: 0;
  }

  .top-controls,
  .mode-strip,
  .playback,
  .tab-list,
  .source-note {
    display: none !important;
  }

  .hero-grid,
  .knowledge-dock {
    box-shadow: none;
    break-inside: avoid;
  }

  .knowledge-dock {
    margin-top: 10px;
  }
}