/* 铜锈工坊 · 可视化步骤手册 */
@import url("https://fonts.googleapis.com/css2?family=IBM+Plex+Mono:wght@400;500&family=Noto+Sans+SC:wght@400;500;600&family=Noto+Serif+SC:wght@500;600;700&display=swap");

:root {
  --ink: #161c19;
  --ink-soft: #3d4943;
  --paper: #e7ebe6;
  --paper-2: #d5dbd4;
  --verdigris: #2f5e4a;
  --verdigris-bright: #4a8a6c;
  --copper: #b56a3a;
  --oxblood: #8c3a2e;
  --azure: #3a5a7a;
  --sulfide: #242826;
  --earth: #8b7355;
  --silver: #7a8e92;
  --warn: #c45c26;
  --danger: #a83228;
  --line: rgba(22, 28, 25, 0.12);
  --shadow: 0 18px 50px rgba(22, 28, 25, 0.12);
  --radius: 2px;
  --font-display: "Noto Serif SC", "Songti SC", serif;
  --font-body: "Noto Sans SC", "PingFang SC", sans-serif;
  --font-mono: "IBM Plex Mono", ui-monospace, monospace;
  --strata-w: 14px;
}

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

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-height: 100vh;
  color: var(--ink);
  background:
    radial-gradient(ellipse 80% 50% at 10% -10%, rgba(74, 138, 108, 0.18), transparent 55%),
    radial-gradient(ellipse 60% 40% at 100% 0%, rgba(181, 106, 58, 0.12), transparent 50%),
    linear-gradient(165deg, #f2f4f1 0%, var(--paper) 40%, #dfe5de 100%);
  font-family: var(--font-body);
  font-size: 15px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  opacity: 0.35;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 200 200' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.85' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='0.45'/%3E%3C/svg%3E");
  z-index: 0;
}

a {
  color: var(--verdigris);
}

button {
  font: inherit;
  cursor: pointer;
  border: none;
  background: none;
  color: inherit;
}

/* —— 锈层剖面条 —— */
.strata-rail {
  position: fixed;
  left: 0;
  top: 0;
  bottom: 0;
  width: var(--strata-w);
  z-index: 40;
  display: flex;
  flex-direction: column;
}

.strata-rail span {
  flex: 1;
  transition: flex 0.45s ease, filter 0.3s;
  position: relative;
}

.strata-rail span.active {
  flex: 2.2;
  filter: brightness(1.15);
}

.strata-rail span::after {
  content: attr(data-label);
  position: absolute;
  left: calc(100% + 10px);
  top: 50%;
  transform: translateY(-50%);
  font-size: 11px;
  letter-spacing: 0.12em;
  writing-mode: vertical-rl;
  opacity: 0;
  pointer-events: none;
  color: var(--ink-soft);
  transition: opacity 0.25s;
  white-space: nowrap;
}

.strata-rail span:hover::after,
.strata-rail span.active::after {
  opacity: 1;
}

.app {
  position: relative;
  z-index: 1;
  padding-left: calc(var(--strata-w) + 8px);
  min-height: 100vh;
}

/* —— 顶栏 —— */
.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 1rem 1.5rem;
  border-bottom: 1px solid var(--line);
  backdrop-filter: blur(10px);
  background: rgba(231, 235, 230, 0.72);
  position: sticky;
  top: 0;
  z-index: 30;
}

.brand {
  display: flex;
  flex-direction: column;
  gap: 0.1rem;
}

.brand strong {
  font-family: var(--font-display);
  font-size: 1.25rem;
  font-weight: 700;
  letter-spacing: 0.08em;
}

.brand span {
  font-size: 0.72rem;
  color: var(--ink-soft);
  letter-spacing: 0.18em;
}

.nav-tabs {
  display: flex;
  gap: 0.35rem;
  flex-wrap: wrap;
  flex-shrink: 1;
}

.nav-tabs button {
  padding: 0.45rem 0.9rem;
  border: 1px solid transparent;
  border-radius: var(--radius);
  font-size: 0.85rem;
  letter-spacing: 0.06em;
  color: var(--ink-soft);
  transition: background 0.2s, color 0.2s, border-color 0.2s;
}

.nav-tabs button:hover,
.nav-tabs button:focus-visible {
  color: var(--ink);
  border-color: var(--line);
  outline: none;
}

.nav-tabs button.active {
  background: var(--ink);
  color: var(--paper);
  border-color: var(--ink);
}

/* —— 视图 —— */
.view {
  display: none;
  padding: 1.5rem clamp(1rem, 3vw, 2.5rem) 3rem;
  animation: rise 0.45s ease both;
}

.view.active {
  display: block;
}

@keyframes rise {
  from {
    opacity: 0;
    transform: translateY(12px);
  }
  to {
    opacity: 1;
    transform: none;
  }
}

/* —— 首页 —— */
.hero {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 2.5rem;
  align-items: end;
  min-height: min(72vh, 640px);
  padding-bottom: 2rem;
  border-bottom: 1px solid var(--line);
}

.hero-copy h1 {
  margin: 0 0 1rem;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(2.4rem, 5.5vw, 4.2rem);
  line-height: 1.15;
  letter-spacing: 0.04em;
}

.hero-copy h1 em {
  font-style: normal;
  color: var(--verdigris);
}

.hero-copy p {
  margin: 0 0 1.5rem;
  max-width: 34em;
  color: var(--ink-soft);
  font-size: 1.05rem;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.75rem 1.25rem;
  border-radius: var(--radius);
  font-size: 0.9rem;
  letter-spacing: 0.06em;
  transition: transform 0.2s, background 0.2s, color 0.2s;
}

.btn:focus-visible {
  outline: 2px solid var(--verdigris);
  outline-offset: 2px;
}

.btn-primary {
  background: var(--verdigris);
  color: #f4f7f4;
}

.btn-primary:hover {
  background: var(--verdigris-bright);
  transform: translateY(-1px);
}

.btn-ghost {
  border: 1px solid var(--ink);
  color: var(--ink);
}

.btn-ghost:hover {
  background: var(--ink);
  color: var(--paper);
}

.oxide-panel {
  position: relative;
  height: min(58vh, 480px);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow);
  background: var(--sulfide);
}

.oxide-layers {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
}

.oxide-layers i {
  display: block;
  flex: 1;
  position: relative;
  animation: breathe 7s ease-in-out infinite;
}

.oxide-layers i:nth-child(1) {
  background: linear-gradient(90deg, #6e2e24, #a84a38 40%, #8c3a2e);
  animation-delay: 0s;
}
.oxide-layers i:nth-child(2) {
  background: linear-gradient(90deg, #1f4636, #3a6b55 45%, #4a8a6c);
  animation-delay: 0.4s;
  flex: 1.4;
}
.oxide-layers i:nth-child(3) {
  background: linear-gradient(90deg, #2a4058, #3a5a7a 50%, #5a7a9a);
  animation-delay: 0.8s;
}
.oxide-layers i:nth-child(4) {
  background: linear-gradient(90deg, #141716, #2a2e2c 40%, #3d4340);
  animation-delay: 1.2s;
}
.oxide-layers i:nth-child(5) {
  background: linear-gradient(90deg, #6a5740, #8b7355 50%, #a89070);
  animation-delay: 1.6s;
}

.oxide-caption {
  position: absolute;
  left: 1.25rem;
  bottom: 1.25rem;
  right: 1.25rem;
  color: #e8ece8;
  font-family: var(--font-display);
  font-size: 1.1rem;
  letter-spacing: 0.12em;
  text-shadow: 0 2px 12px rgba(0, 0, 0, 0.45);
}

.oxide-caption small {
  display: block;
  margin-top: 0.35rem;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.04em;
  opacity: 0.8;
}

@keyframes breathe {
  0%,
  100% {
    filter: brightness(1);
  }
  50% {
    filter: brightness(1.08);
  }
}

.disclaimer {
  margin-top: 1.5rem;
  padding: 0.85rem 1rem;
  border-left: 3px solid var(--warn);
  background: rgba(196, 92, 38, 0.08);
  color: var(--ink-soft);
  font-size: 0.85rem;
}

.home-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 1rem;
  margin-top: 2rem;
}

.home-card {
  text-align: left;
  padding: 1.15rem 1.2rem;
  background: rgba(255, 255, 255, 0.45);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  transition: border-color 0.2s, transform 0.2s, background 0.2s;
}

.home-card:hover,
.home-card:focus-visible {
  border-color: var(--verdigris);
  background: rgba(255, 255, 255, 0.7);
  transform: translateY(-2px);
  outline: none;
}

.home-card .code {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--verdigris);
  letter-spacing: 0.08em;
}

.home-card h3 {
  margin: 0.35rem 0 0.4rem;
  font-family: var(--font-display);
  font-size: 1.15rem;
  font-weight: 600;
}

.home-card p {
  margin: 0;
  font-size: 0.82rem;
  color: var(--ink-soft);
}

.home-card .meta {
  display: flex;
  gap: 0.6rem;
  margin-top: 0.85rem;
  font-family: var(--font-mono);
  font-size: 0.68rem;
  color: var(--ink-soft);
}

/* —— 知识库 —— */
.section-head {
  margin-bottom: 1.5rem;
}

.section-head h2 {
  margin: 0 0 0.4rem;
  font-family: var(--font-display);
  font-size: clamp(1.6rem, 3vw, 2.2rem);
  letter-spacing: 0.06em;
}

.section-head p {
  margin: 0;
  color: var(--ink-soft);
  max-width: 40em;
}

.knowledge-list {
  display: grid;
  gap: 1rem;
}

.knowledge-item {
  display: grid;
  grid-template-columns: 140px 1fr;
  gap: 1.25rem;
  padding: 1.25rem 1.4rem;
  background: rgba(255, 255, 255, 0.4);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.knowledge-item h3 {
  margin: 0 0 0.35rem;
  font-family: var(--font-display);
  font-size: 1.2rem;
}

.knowledge-item .summary {
  margin: 0 0 0.75rem;
  color: var(--ink-soft);
  font-size: 0.9rem;
}

.knowledge-item ul {
  margin: 0;
  padding-left: 1.1rem;
}

.knowledge-item li {
  margin-bottom: 0.35rem;
}

.knowledge-item li:last-child {
  margin-bottom: 0;
}

.k-index {
  font-family: var(--font-mono);
  font-size: 2rem;
  color: var(--verdigris);
  opacity: 0.55;
  line-height: 1;
}

/* —— 工艺目录 —— */
.catalog-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1rem;
}

.sop-tile {
  display: flex;
  flex-direction: column;
  align-items: stretch;
  text-align: left;
  padding: 0;
  overflow: hidden;
  background: rgba(255, 255, 255, 0.5);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  transition: transform 0.25s, box-shadow 0.25s, border-color 0.25s;
}

.sop-tile:hover,
.sop-tile:focus-visible {
  transform: translateY(-3px);
  box-shadow: var(--shadow);
  border-color: var(--verdigris);
  outline: none;
}

.sop-tile .stripe {
  height: 6px;
  width: 100%;
}

.sop-tile .body {
  padding: 1.1rem 1.2rem 1.25rem;
}

.sop-tile .code {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.1em;
  color: var(--ink-soft);
}

.sop-tile h3 {
  margin: 0.3rem 0 0.5rem;
  font-family: var(--font-display);
  font-size: 1.25rem;
}

.sop-tile .goal {
  margin: 0;
  flex: 1;
  font-size: 0.84rem;
  color: var(--ink-soft);
}

.sop-tile .foot {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: 1rem;
  font-family: var(--font-mono);
  font-size: 0.7rem;
}

.risk {
  padding: 0.15rem 0.45rem;
  border-radius: var(--radius);
  background: rgba(22, 28, 25, 0.06);
}

.risk.低 {
  color: var(--verdigris);
  background: rgba(47, 94, 74, 0.12);
}
.risk.中 {
  color: var(--warn);
  background: rgba(196, 92, 38, 0.12);
}
.risk.高 {
  color: var(--danger);
  background: rgba(168, 50, 40, 0.12);
}

/* —— 步骤查看器 —— */
.viewer {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 300px;
  gap: 1.5rem;
  align-items: start;
}

.viewer-main {
  min-width: 0;
}

.viewer-head {
  margin-bottom: 1.25rem;
}

.viewer-head .eyebrow {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  align-items: center;
  margin-bottom: 0.5rem;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--ink-soft);
}

.viewer-head h2 {
  margin: 0 0 0.5rem;
  font-family: var(--font-display);
  font-size: clamp(1.6rem, 3vw, 2.3rem);
  letter-spacing: 0.05em;
}

.viewer-head .goal {
  margin: 0;
  color: var(--ink-soft);
  max-width: 42em;
}

.progress-track {
  display: flex;
  gap: 4px;
  margin: 1.25rem 0 1.5rem;
}

.progress-track button {
  flex: 1;
  height: 6px;
  border-radius: 1px;
  background: var(--paper-2);
  transition: background 0.25s, transform 0.2s;
}

.progress-track button.done {
  background: var(--verdigris);
}

.progress-track button.current {
  background: var(--copper);
  transform: scaleY(1.6);
}

.progress-track button:hover,
.progress-track button:focus-visible {
  outline: none;
  background: var(--verdigris-bright);
}

.step-stage {
  position: relative;
  padding: 1.75rem 1.6rem 1.6rem;
  background: rgba(255, 255, 255, 0.55);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  min-height: 280px;
}

.step-num {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  letter-spacing: 0.14em;
  color: var(--copper);
  margin-bottom: 0.75rem;
}

.step-stage h3 {
  margin: 0 0 0.85rem;
  font-family: var(--font-display);
  font-size: 1.55rem;
  letter-spacing: 0.04em;
}

.step-stage .detail {
  margin: 0 0 1rem;
  font-size: 1.02rem;
  max-width: 40em;
}

.step-tip {
  margin: 0;
  padding: 0.75rem 0.9rem;
  border-left: 3px solid var(--verdigris);
  background: rgba(47, 94, 74, 0.08);
  font-size: 0.88rem;
  color: var(--ink-soft);
}

.step-nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  margin-top: 1.25rem;
}

.step-nav .counter {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--ink-soft);
}

.side-panel {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  position: sticky;
  top: 5.5rem;
}

.panel-block {
  padding: 1rem 1.1rem;
  background: rgba(255, 255, 255, 0.5);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.panel-block h4 {
  margin: 0 0 0.75rem;
  font-family: var(--font-display);
  font-size: 0.95rem;
  letter-spacing: 0.08em;
}

.formula-list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.formula-list li {
  display: flex;
  flex-direction: column;
  gap: 0.15rem;
  padding: 0.55rem 0;
  border-bottom: 1px solid var(--line);
  font-size: 0.84rem;
}

.formula-list li:last-child {
  border-bottom: none;
  padding-bottom: 0;
}

.formula-list .name {
  font-weight: 600;
}

.formula-list .detail {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--ink-soft);
}

.safety-list,
.check-list {
  margin: 0;
  padding-left: 1.1rem;
  font-size: 0.84rem;
}

.safety-list li {
  margin-bottom: 0.4rem;
  color: var(--oxblood);
}

.check-list li {
  margin-bottom: 0.35rem;
  color: var(--ink-soft);
}

.panel-block.danger {
  border-color: rgba(168, 50, 40, 0.35);
  background: rgba(168, 50, 40, 0.06);
}

.sop-switcher {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  margin-bottom: 1.25rem;
}

.sop-switcher button {
  padding: 0.35rem 0.65rem;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  font-family: var(--font-mono);
  font-size: 0.68rem;
  color: var(--ink-soft);
}

.sop-switcher button.active {
  background: var(--ink);
  color: var(--paper);
  border-color: var(--ink);
}

.sop-switcher button:hover,
.sop-switcher button:focus-visible {
  border-color: var(--verdigris);
  color: var(--ink);
  outline: none;
}

.sop-switcher button.active:hover {
  color: var(--paper);
}

.done-banner {
  display: none;
  margin-top: 1rem;
  padding: 1rem 1.1rem;
  background: rgba(47, 94, 74, 0.12);
  border: 1px solid rgba(47, 94, 74, 0.3);
  border-radius: var(--radius);
}

.done-banner.show {
  display: block;
  animation: rise 0.4s ease both;
}

.done-banner strong {
  font-family: var(--font-display);
}

/* —— 实验方法简页 —— */
.flow {
  display: grid;
  gap: 0;
  max-width: 720px;
}

.flow-step {
  display: grid;
  grid-template-columns: 56px 1fr;
  gap: 1rem;
  padding: 1.1rem 0;
  border-bottom: 1px solid var(--line);
}

.flow-step:last-child {
  border-bottom: none;
}

.flow-n {
  font-family: var(--font-mono);
  font-size: 1.4rem;
  color: var(--copper);
}

.flow-step h3 {
  margin: 0 0 0.35rem;
  font-family: var(--font-display);
  font-size: 1.1rem;
}

.flow-step p {
  margin: 0;
  color: var(--ink-soft);
  font-size: 0.9rem;
}

/* —— 原文 —— */
.originals-layout {
  display: grid;
  grid-template-columns: 200px minmax(0, 1fr);
  gap: 1.25rem;
  align-items: start;
}

.doc-nav {
  position: sticky;
  top: 5.5rem;
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
  max-height: calc(100vh - 7rem);
  overflow-y: auto;
  padding-right: 0.25rem;
}

.doc-nav button {
  text-align: left;
  padding: 0.45rem 0.65rem;
  border: 1px solid transparent;
  border-radius: var(--radius);
  font-size: 0.78rem;
  color: var(--ink-soft);
  line-height: 1.35;
  transition: background 0.2s, color 0.2s, border-color 0.2s;
}

.doc-nav button:hover,
.doc-nav button:focus-visible {
  color: var(--ink);
  border-color: var(--line);
  outline: none;
}

.doc-nav button.active {
  background: var(--ink);
  color: var(--paper);
  border-color: var(--ink);
}

.doc-nav .doc-code {
  display: block;
  font-family: var(--font-mono);
  font-size: 0.65rem;
  letter-spacing: 0.06em;
  opacity: 0.75;
  margin-bottom: 0.1rem;
}

.md-body {
  padding: 1.4rem 1.5rem 2rem;
  background: rgba(255, 255, 255, 0.55);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  max-width: 52rem;
  overflow-x: auto;
}

.md-loading,
.md-error {
  margin: 0;
  color: var(--ink-soft);
}

.md-error {
  color: var(--danger);
}

.md-body h1,
.md-body h2,
.md-body h3,
.md-body h4 {
  font-family: var(--font-display);
  letter-spacing: 0.04em;
  line-height: 1.35;
  margin: 1.6rem 0 0.7rem;
}

.md-body h1 {
  font-size: 1.55rem;
  margin-top: 0;
  padding-bottom: 0.6rem;
  border-bottom: 1px solid var(--line);
}

.md-body h2 {
  font-size: 1.25rem;
  color: var(--verdigris);
}

.md-body h3 {
  font-size: 1.08rem;
}

.md-body h4 {
  font-size: 0.98rem;
}

.md-body p,
.md-body li {
  font-size: 0.92rem;
  color: var(--ink);
}

.md-body p {
  margin: 0.65rem 0;
}

.md-body ul,
.md-body ol {
  margin: 0.5rem 0 0.8rem;
  padding-left: 1.35rem;
}

.md-body li {
  margin-bottom: 0.3rem;
}

.md-body blockquote {
  margin: 0.9rem 0;
  padding: 0.7rem 0.9rem;
  border-left: 3px solid var(--copper);
  background: rgba(181, 106, 58, 0.08);
  color: var(--ink-soft);
  font-size: 0.88rem;
}

.md-body blockquote p {
  margin: 0.35rem 0;
  color: inherit;
}

.md-body hr {
  border: none;
  border-top: 1px solid var(--line);
  margin: 1.5rem 0;
}

.md-body code {
  font-family: var(--font-mono);
  font-size: 0.82em;
  background: rgba(22, 28, 25, 0.06);
  padding: 0.1em 0.35em;
  border-radius: 2px;
}

.md-body pre {
  margin: 0.9rem 0;
  padding: 0.9rem 1rem;
  background: var(--sulfide);
  color: #d8e0d8;
  border-radius: var(--radius);
  overflow-x: auto;
  font-size: 0.8rem;
  line-height: 1.55;
}

.md-body pre code {
  background: none;
  padding: 0;
  color: inherit;
  font-size: inherit;
}

.md-body table {
  width: 100%;
  border-collapse: collapse;
  margin: 0.9rem 0 1.1rem;
  font-size: 0.82rem;
  display: block;
  overflow-x: auto;
}

.md-body th,
.md-body td {
  border: 1px solid var(--line);
  padding: 0.45rem 0.6rem;
  text-align: left;
  vertical-align: top;
}

.md-body th {
  background: rgba(47, 94, 74, 0.1);
  font-weight: 600;
  white-space: nowrap;
}

.md-body a {
  color: var(--verdigris);
  text-decoration: underline;
  text-underline-offset: 2px;
}

.md-body strong {
  font-weight: 600;
}

/* —— 页脚 —— */
.site-foot {
  padding: 1.5rem clamp(1rem, 3vw, 2.5rem) 2rem;
  border-top: 1px solid var(--line);
  font-size: 0.78rem;
  color: var(--ink-soft);
  letter-spacing: 0.04em;
}

/* —— 响应式 —— */
@media (max-width: 960px) {
  .hero {
    grid-template-columns: 1fr;
    min-height: auto;
    gap: 1.5rem;
  }

  .oxide-panel {
    height: 260px;
  }

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

  .side-panel {
    position: static;
  }

  .knowledge-item {
    grid-template-columns: 1fr;
  }

  .k-index {
    font-size: 1.2rem;
  }

  .originals-layout {
    grid-template-columns: 1fr;
  }

  .doc-nav {
    position: static;
    max-height: none;
    flex-direction: row;
    flex-wrap: wrap;
    gap: 0.3rem;
  }

  .doc-nav button {
    font-size: 0.7rem;
    padding: 0.35rem 0.5rem;
  }

  .doc-nav .doc-code {
    display: inline;
    margin-right: 0.25rem;
  }

  .md-body {
    padding: 1rem 0.95rem 1.4rem;
  }
}

@media (max-width: 640px) {
  .topbar {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.55rem;
    padding: 0.75rem 0.85rem;
  }

  .brand strong {
    font-size: 1.05rem;
  }

  .nav-tabs {
    gap: 0.15rem;
    width: 100%;
  }

  .nav-tabs button {
    padding: 0.25rem 0.36rem;
    font-size: 0.62rem;
    letter-spacing: 0;
  }

  .app {
    padding-left: var(--strata-w);
  }

  .strata-rail span::after {
    display: none;
  }

  .step-nav {
    flex-wrap: wrap;
  }

  .step-nav .btn {
    flex: 1;
    justify-content: center;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation: none !important;
    transition: none !important;
  }
}