:root {
  --bg: #e7ebee;
  --bg-strong: #d4dbe0;
  --surface: rgba(247, 249, 250, 0.88);
  --surface-strong: #fbfcfd;
  --surface-muted: #dde4e8;
  --text: #2f404f;
  --text-soft: #667685;
  --line: rgba(63, 86, 104, 0.14);
  --shadow: 0 20px 60px rgba(73, 95, 116, 0.16);
  --green: #3f88c5;
  --green-deep: #5f7f97;
  --orange: #b5847c;
  --sand: #c9d3dc;
  --clay: #c8b2ab;
  --mint: #b8c5d0;
  --radius-xl: 32px;
  --radius-lg: 24px;
  --radius-md: 18px;
  --radius-sm: 12px;
  --side-padding: clamp(16px, 3vw, 40px);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: "Noto Sans TC", "Microsoft JhengHei", sans-serif;
  color: var(--text);
  background:
    radial-gradient(circle at top left, rgba(63, 136, 197, 0.22), transparent 34%),
    radial-gradient(circle at 85% 12%, rgba(184, 197, 208, 0.5), transparent 24%),
    linear-gradient(180deg, #f0f3f5 0%, #dde4e8 48%, #eef2f4 100%);
}

a {
  color: inherit;
}

img {
  display: block;
  max-width: 100%;
}

.page-glow {
  position: fixed;
  border-radius: 999px;
  filter: blur(18px);
  opacity: 0.55;
  pointer-events: none;
  z-index: 0;
}

.page-glow-a {
  inset: 8% auto auto 4%;
  width: 220px;
  height: 220px;
  background: rgba(63, 136, 197, 0.18);
}

.page-glow-b {
  inset: auto 5% 8% auto;
  width: 280px;
  height: 280px;
  background: rgba(184, 197, 208, 0.24);
}

.site-header,
.hero,
.main-shell,
.site-footer {
  position: relative;
  z-index: 1;
}

.page-frame {
  width: calc(100% - (var(--side-padding) * 2));
  margin-inline: auto;
}

.site-header {
  position: sticky;
  top: 18px;
  z-index: 10;
  padding: 0;
}

.site-header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  position: relative;
  padding: 12px 16px;
  border-radius: 24px;
  background: rgba(241, 245, 247, 0.78);
  border: 1px solid rgba(255, 255, 255, 0.45);
  box-shadow: 0 10px 28px rgba(92, 107, 123, 0.08);
  backdrop-filter: blur(12px);
}

.nav-toggle {
  appearance: none;
  width: 46px;
  height: 46px;
  display: none;
  place-items: center;
  gap: 5px;
  padding: 10px;
  border: 0;
  border-radius: 14px;
  background: rgba(255, 255, 255, 0.74);
  box-shadow: 0 8px 20px rgba(92, 107, 123, 0.1);
  cursor: pointer;
}

  .nav-toggle-line,
  .nav-toggle-line::before,
  .nav-toggle-line::after {
    display: block;
  width: 20px;
  height: 2px;
  border-radius: 999px;
  background: var(--green-deep);
}

  .nav-toggle-line {
    position: relative;
  }

  .nav-toggle-line::before,
  .nav-toggle-line::after {
    content: "";
    position: absolute;
    left: 0;
  }

  .nav-toggle-line::before {
    top: -7px;
  }

  .nav-toggle-line::after {
    top: 7px;
  }

.site-brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  color: inherit;
  text-decoration: none;
  flex-shrink: 0;
}

.site-brand-icon {
  width: 44px;
  height: 44px;
  border-radius: 14px;
  object-fit: cover;
  box-shadow: 0 10px 22px rgba(77, 97, 118, 0.16);
}

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

.site-brand-copy strong {
  font-size: 0.96rem;
}

.site-brand-copy span {
  color: var(--text-soft);
  font-size: 0.82rem;
}

.hero {
  width: var(--content-width);
  margin: 0 auto 24px;
  padding: 36px;
  display: grid;
  grid-template-columns: minmax(0, 1.5fr) minmax(280px, 0.8fr);
  gap: 24px;
  border: 1px solid rgba(255, 255, 255, 0.42);
  border-radius: var(--radius-xl);
  background: linear-gradient(145deg, rgba(248, 250, 251, 0.94), rgba(224, 231, 236, 0.86));
  box-shadow: var(--shadow);
  overflow: hidden;
}

.site-panels .hero {
  width: 100%;
}

.hero::after {
  content: "";
  position: absolute;
  inset: auto -80px -120px auto;
  width: 260px;
  height: 260px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(63, 136, 197, 0.22), transparent 65%);
}

.brand-strip {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-bottom: 20px;
}

.brand-icon {
  width: 64px;
  height: 64px;
  border-radius: 18px;
  object-fit: cover;
  box-shadow: 0 14px 28px rgba(77, 97, 118, 0.18);
}

.brand-meta {
  display: grid;
  gap: 4px;
}

.brand-meta .eyebrow {
  margin: 0;
}

.brand-caption {
  margin: 0;
  color: var(--text-soft);
  font-size: 0.95rem;
}

.eyebrow,
.card-kicker,
.toc-title {
  margin: 0 0 10px;
  font-size: 0.82rem;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--green);
}

.hero h1,
.section-intro h2,
.overview-card h2,
.spotlight-panel h2 {
  margin: 0;
  font-family: "Noto Serif TC", serif;
  font-weight: 700;
  line-height: 1.2;
}

.hero h1 {
  font-size: clamp(2.2rem, 5vw, 4.2rem);
  max-width: 11ch;
}

.hero-text {
  max-width: 62ch;
  font-size: 1.02rem;
  line-height: 1.85;
  color: var(--text-soft);
}

.button {
  appearance: none;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 14px 22px;
  border: 0;
  border-radius: 999px;
  background: transparent;
  text-decoration: none;
  font: inherit;
  font-weight: 700;
  cursor: pointer;
  transition: transform 180ms ease, box-shadow 180ms ease, background-color 180ms ease;
}

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

.button:focus-visible {
  outline: none;
}

.button-primary {
  color: #fff8f1;
  background: linear-gradient(135deg, var(--green), var(--green-deep));
  box-shadow: 0 14px 30px rgba(63, 136, 197, 0.22);
}

.hero-card,
.overview-card,
.spotlight-panel,
.toc-card,
.manual-article,
.faq-group,
.site-footer {
  backdrop-filter: blur(10px);
}

.hero-card {
  align-self: end;
  padding: 24px;
  border-radius: var(--radius-lg);
  background: rgba(250, 252, 253, 0.74);
  border: 1px solid rgba(63, 86, 104, 0.08);
}

.feature-list {
  margin: 0;
  padding-left: 1.1rem;
  line-height: 1.85;
  color: var(--text-soft);
}

.main-shell {
  margin: 36px auto 36px;
}

.overview-grid,
.spotlight-grid {
  display: grid;
  gap: 18px;
}

.overview-grid {
  grid-template-columns: repeat(3, minmax(0, 1fr));
  margin-bottom: 18px;
}

.overview-card,
.spotlight-panel,
.faq-group {
  padding: 24px;
  border-radius: var(--radius-lg);
  background: rgba(248, 250, 251, 0.84);
  border: 1px solid rgba(63, 86, 104, 0.08);
  box-shadow: 0 14px 38px rgba(92, 107, 123, 0.08);
}

.accent-sand {
  background: linear-gradient(180deg, rgba(249, 251, 252, 0.96), rgba(201, 211, 220, 0.34));
}

.accent-mint {
  background: linear-gradient(180deg, rgba(249, 251, 252, 0.96), rgba(184, 197, 208, 0.3));
}

.accent-clay {
  background: linear-gradient(180deg, rgba(250, 251, 252, 0.96), rgba(200, 178, 171, 0.28));
}

.spotlight-grid {
  grid-template-columns: repeat(2, minmax(0, 1fr));
  margin-bottom: 26px;
}

.panel-heading {
  margin-bottom: 18px;
}

.pill-group {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.pill {
  padding: 10px 14px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.7);
  border: 1px solid rgba(63, 86, 104, 0.08);
  font-size: 0.94rem;
}

.site-panels {
  padding: 16px;
  border-radius: calc(var(--radius-xl) + 4px);
  background: rgba(247, 250, 251, 0.58);
  border: 1px solid rgba(255, 255, 255, 0.35);
  box-shadow: var(--shadow);
}

.panel-nav {
  display: flex;
  flex-wrap: nowrap;
  gap: 12px;
  margin-bottom: 0;
  padding: 0;
  border-radius: 999px;
  background: transparent;
  border: 0;
}

.site-nav {
  flex: 1;
  width: auto;
  justify-content: flex-end;
}

.site-branding {
  margin-bottom: 0;
  flex-shrink: 0;
}

.panel-tab {
  appearance: none;
  border: 0;
  border-radius: 999px;
  padding: 12px 18px;
  background: transparent;
  color: var(--text-soft);
  font: inherit;
  font-weight: 700;
  cursor: pointer;
  transition: background-color 180ms ease, color 180ms ease, transform 180ms ease;
}

.panel-tab:hover,
.panel-tab:focus-visible {
  background: rgba(255, 255, 255, 0.76);
  outline: none;
}

.panel-tab.is-active {
  color: #fff9f0;
  background: linear-gradient(135deg, var(--green), var(--green-deep));
  box-shadow: 0 10px 24px rgba(63, 136, 197, 0.2);
}

.content-panel {
  display: none;
}

.content-panel.is-active {
  display: block;
  animation: panel-rise 260ms ease;
}

@keyframes panel-rise {
  from {
    opacity: 0;
    transform: translateY(10px);
  }

  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.section-intro {
  padding: 18px 8px 24px;
}

.section-intro p:last-child {
  max-width: 100%;
  color: var(--text-soft);
  line-height: 1.8;
  word-break: normal;
  overflow-wrap: break-word;
  line-break: auto;
  text-wrap: wrap;
}

.manual-shell {
  display: grid;
  grid-template-columns: 280px minmax(0, 1fr);
  gap: 18px;
  align-items: start;
}

.manual-toc {
  position: sticky;
  top: 92px;
}

.toc-card {
  max-height: calc(100vh - 116px);
  overflow: auto;
  padding: 18px;
  border-radius: var(--radius-lg);
  background: rgba(249, 251, 252, 0.9);
  border: 1px solid rgba(63, 86, 104, 0.08);
}

.toc-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 10px;
}

.toc-head .toc-title {
  margin: 0;
}

.toc-toggle {
  display: none;
  align-items: center;
  gap: 8px;
  appearance: none;
  border: 0;
  border-radius: 999px;
  padding: 8px 12px;
  background: rgba(255, 255, 255, 0.78);
  color: var(--text-soft);
  font: inherit;
  font-size: 0.9rem;
  font-weight: 700;
  cursor: pointer;
}

.toc-toggle-icon {
  width: 9px;
  height: 9px;
  border-right: 2px solid currentColor;
  border-bottom: 2px solid currentColor;
  transform: rotate(45deg) translateY(-1px);
  transition: transform 180ms ease;
}

.toc-card.is-collapsed .toc-toggle-icon {
  transform: rotate(-45deg) translateY(1px);
}

.toc-links {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.toc-tree,
.toc-children {
  list-style: none;
  margin: 0;
  padding: 0;
}

.toc-tree {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.toc-children {
  margin-top: 6px;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.toc-children[hidden] {
  display: none;
}

.toc-link {
   display: flex;
  align-items: center;
  gap: 8px;
  width: 100%;
  padding: 9px 12px;
  border: 0;
  border-radius: 12px;
  background: transparent;
  text-decoration: none;
  color: var(--text-soft);
  font: inherit;
  line-height: 1.45;
  text-align: left;
  cursor: pointer;
}

.toc-link:hover,
.toc-link:focus-visible {
  background: rgba(63, 136, 197, 0.08);
  color: var(--green-deep);
  outline: none;
}

.toc-link.is-active {
  background: rgba(63, 136, 197, 0.14);
  color: var(--green-deep);
  box-shadow: inset 3px 0 0 var(--green);
  font-weight: 800;
}

.toc-link.depth-1 {
  font-weight: 700;
}

.toc-link-numbered {
  align-items: flex-start;
  justify-content: flex-start;
}

.toc-number {
  min-width: 2.8rem;
  flex: 0 0 auto;
  color: var(--green);
  font-weight: 800;
}

.toc-text {
  min-width: 0;
}

.toc-toggle {
  font-weight: 700;
  justify-content: space-between;
}

.toc-caret {
  width: 0;
  height: 0;
  flex: 0 0 auto;
  border-top: 5px solid transparent;
  border-bottom: 5px solid transparent;
  border-left: 6px solid currentColor;
  transition: transform 180ms ease;
}

.toc-item-expanded > .toc-toggle .toc-caret {
  transform: rotate(90deg);
}

.toc-link.depth-2 {
  padding-left: 20px;
}

.toc-link.depth-3,
.toc-link.depth-4 {
  padding-left: 30px;
  font-size: 0.94rem;
}

.manual-article {
  padding: 28px;
  border-radius: var(--radius-lg);
  background: rgba(250, 252, 253, 0.92);
  border: 1px solid rgba(63, 86, 104, 0.08);
}

.loading-state,
.manual-error {
  min-height: 220px;
  display: grid;
  place-items: center;
  text-align: center;
  color: var(--text-soft);
}

.manual-error {
  padding: 24px;
  border-radius: var(--radius-md);
  background: rgba(181, 132, 124, 0.14);
}

.manual-body {
  font-size: 1rem;
  line-height: 1.82;
}

.manual-body h1,
.manual-body h2,
.manual-body h3,
.manual-body h4 {
  scroll-margin-top: 100px;
  line-height: 1.35;
}

.manual-body h1,
.manual-body h2 {
  margin-top: 2.4rem;
  margin-bottom: 1rem;
  padding-bottom: 0.45rem;
  font-family: "Noto Serif TC", serif;
  border-bottom: 1px solid rgba(32, 49, 43, 0.08);
}

.manual-body h1:first-child {
  margin-top: 0;
}

.manual-body h3,
.manual-body h4 {
  margin-top: 1.6rem;
  margin-bottom: 0.65rem;
}

.manual-body p,
.manual-body ul,
.manual-body ol,
.manual-body blockquote,
.manual-body table,
.manual-body .image-grid,
.manual-body hr {
  margin: 0 0 1.1rem;
}

.manual-body ul,
.manual-body ol {
  padding-left: 1.4rem;
}

.manual-body li + li {
  margin-top: 0.35rem;
}

.manual-body strong {
  color: var(--green-deep);
}

.manual-body a {
  color: var(--orange);
  text-underline-offset: 0.18em;
}

.manual-body blockquote {
  padding: 14px 18px;
  border-left: 4px solid var(--orange);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  background: rgba(181, 132, 124, 0.09);
}

.manual-body hr {
  border: 0;
  border-top: 1px dashed rgba(32, 49, 43, 0.18);
}

.manual-body table {
  width: 100%;
  border-collapse: collapse;
  border-radius: 16px;
  overflow: hidden;
  background: rgba(255, 255, 255, 0.78);
}

.manual-body th,
.manual-body td {
  padding: 12px 14px;
  border: 1px solid rgba(32, 49, 43, 0.08);
  text-align: left;
  vertical-align: top;
}

.manual-body th {
  background: rgba(63, 136, 197, 0.12);
}

.image-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 14px;
}

.image-card {
  overflow: hidden;
  border-radius: 18px;
  border: 1px solid rgba(63, 86, 104, 0.08);
  background: rgba(255, 255, 255, 0.76);
}

.image-card img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  cursor: zoom-in;
}

body.is-lightbox-open {
  overflow: hidden;
}

.image-lightbox {
  position: fixed;
  inset: 0;
  z-index: 100;
  display: none;
  align-items: center;
  justify-content: center;
  padding: 72px 28px 32px;
  background: rgba(20, 30, 38, 0.78);
  backdrop-filter: blur(8px);
  touch-action: none;
}

.image-lightbox.is-open {
  display: flex;
}

.image-lightbox-image {
  max-width: min(100%, 1280px);
  max-height: calc(100vh - 112px);
  width: auto;
  height: auto;
  object-fit: contain;
  border-radius: 12px;
  background: rgba(255, 255, 255, 0.96);
  box-shadow: 0 24px 80px rgba(0, 0, 0, 0.34);
  cursor: zoom-in;
  touch-action: none;
  transform-origin: center center;
  transition: transform 120ms ease;
  user-select: none;
}

.image-lightbox-image.is-zoomed {
  cursor: grab;
  transition: none;
}

.image-lightbox-image.is-zoomed:active {
  cursor: grabbing;
}

.image-lightbox-close {
  appearance: none;
  position: absolute;
  top: 22px;
  right: 24px;
  width: 44px;
  height: 44px;
  display: grid;
  place-items: center;
  border: 0;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.92);
  color: var(--text);
  font: inherit;
  font-size: 1.8rem;
  line-height: 1;
  cursor: pointer;
  box-shadow: 0 12px 32px rgba(0, 0, 0, 0.18);
}

.image-lightbox-close:hover,
.image-lightbox-close:focus-visible {
  outline: none;
  background: #fff;
  color: var(--green);
}

.page-break {
  height: 1px;
  margin: 1.8rem 0;
  background: linear-gradient(90deg, transparent, rgba(63, 136, 197, 0.2), transparent);
}

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

.contact-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.15fr) minmax(0, 1fr);
  gap: 18px;
}

.contact-card {
  padding: 24px;
  border-radius: var(--radius-lg);
  background: rgba(248, 250, 251, 0.84);
  border: 1px solid rgba(63, 86, 104, 0.08);
  box-shadow: 0 14px 38px rgba(92, 107, 123, 0.08);
}

.contact-card-primary {
  background: linear-gradient(180deg, rgba(249, 251, 252, 0.96), rgba(184, 197, 208, 0.28));
}

.contact-form-card {
  grid-column: 1 / -1;
}

.contact-card h3 {
  margin: 0 0 12px;
  font-family: "Noto Serif TC", serif;
  font-size: 1.4rem;
}

.contact-copy {
  margin: 0 0 18px;
  color: var(--text-soft);
  line-height: 1.8;
}

.contact-meta {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px 14px;
  margin-bottom: 18px;
}

.contact-label {
  display: block;
  margin-bottom: 6px;
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  color: var(--green);
}

.contact-meta p,
.contact-alert p {
  margin: 0;
  line-height: 1.75;
}

.contact-list {
  margin: 0;
  padding-left: 1.2rem;
  line-height: 1.85;
  color: var(--text-soft);
}

.contact-list-numbered {
  padding-left: 1.3rem;
}

.contact-alert {
  margin-top: 18px;
  padding: 16px 18px;
  border-radius: var(--radius-md);
  background: rgba(181, 132, 124, 0.1);
  border: 1px solid rgba(181, 132, 124, 0.14);
}

.contact-alert strong {
  display: block;
  margin-bottom: 8px;
  color: var(--green-deep);
}

.contact-form {
  display: grid;
  gap: 18px;
}

.form-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
}

.form-field {
  display: grid;
  gap: 8px;
}

.form-field span {
  font-size: 0.92rem;
  font-weight: 700;
  color: var(--green-deep);
}

.form-field input,
.form-field select,
.form-field textarea {
  width: 100%;
  padding: 14px 16px;
  border: 1px solid rgba(63, 86, 104, 0.12);
  border-radius: 14px;
  background: rgba(255, 255, 255, 0.85);
  color: var(--text);
  font: inherit;
}

.form-field textarea {
  resize: vertical;
  min-height: 140px;
}

.form-field input:focus,
.form-field select:focus,
.form-field textarea:focus {
  outline: 2px solid rgba(63, 136, 197, 0.18);
  border-color: rgba(63, 136, 197, 0.4);
}

.form-field-full {
  grid-column: 1 / -1;
}

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

.form-actions {
  display: flex;
  align-items: center;
  gap: 14px;
  flex-wrap: wrap;
}

.form-note,
.form-status {
  margin: 0;
  color: var(--text-soft);
  line-height: 1.7;
}

.form-status {
  min-height: 1.7em;
}

.form-status.is-success {
  color: var(--green-deep);
}

.form-status.is-error {
  color: #9a5348;
}

.faq-group h3 {
  margin: 0 0 12px;
  font-family: "Noto Serif TC", serif;
}

.faq-item {
  border-top: 1px solid rgba(63, 86, 104, 0.08);
}

.faq-item:first-of-type {
  border-top: 0;
}

.faq-question {
  width: 100%;
  padding: 16px 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  border: 0;
  background: transparent;
  color: var(--text);
  font: inherit;
  font-weight: 700;
  text-align: left;
  cursor: pointer;
}

.faq-question span:last-child {
  color: var(--green);
  font-size: 1.25rem;
}

.faq-answer {
  display: none;
  padding: 0 0 16px;
  color: var(--text-soft);
  line-height: 1.8;
}

.faq-item.is-open .faq-answer {
  display: block;
}

.site-footer {
  margin: 0 auto 30px;
  padding: 18px 22px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  flex-wrap: wrap;
  border-radius: 18px;
  background: rgba(249, 251, 252, 0.82);
  border: 1px solid rgba(63, 86, 104, 0.08);
}

.footer-logo {
  width: min(220px, 60vw);
  height: auto;
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: 10px;
}

.footer-link {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  text-decoration: none;
}

.footer-link-separator {
  color: rgba(63, 86, 104, 0.3);
  font-size: 0.9rem;
  user-select: none;
}

.footer-link:hover,
.footer-link:focus-visible {
  outline: none;
}

.footer-link.is-active {
  color: #fff9f0;
}

.back-to-top {
  appearance: none;
  position: fixed;
  right: 24px;
  bottom: 24px;
  z-index: 20;
  width: 52px;
  height: 52px;
  display: grid;
  place-items: center;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--green), var(--green-deep));
  border: 1px solid rgba(255, 255, 255, 0.45);
  box-shadow: 0 14px 30px rgba(63, 136, 197, 0.28);
  cursor: pointer;
  transition: transform 180ms ease, box-shadow 180ms ease;
}

.back-to-top:hover,
.back-to-top:focus-visible {
  transform: translateY(-2px);
  box-shadow: 0 18px 36px rgba(63, 136, 197, 0.34);
  outline: none;
}

.back-to-top span {
  width: 14px;
  height: 14px;
  border-top: 3px solid #fff;
  border-left: 3px solid #fff;
  transform: translateY(4px) rotate(45deg);
}

@media (max-width: 1080px) {
  .hero,
  .overview-grid,
  .spotlight-grid,
  .manual-shell,
  .faq-grid,
  .contact-grid {
    grid-template-columns: 1fr;
  }

  .site-header-inner {
    justify-content: space-between;
  }

  .nav-toggle {
    display: grid;
  }

  .site-nav {
    position: absolute;
    top: calc(100% + 8px);
    right: 0;
    width: min(280px, calc(100vw - 32px));
    display: none;
    flex-direction: column;
    align-items: stretch;
    gap: 8px;
    padding: 12px;
    border-radius: 18px;
    background: rgba(241, 245, 247, 0.96);
    border: 1px solid rgba(255, 255, 255, 0.58);
    box-shadow: 0 18px 42px rgba(73, 95, 116, 0.18);
    backdrop-filter: blur(12px);
  }

  .site-header.is-nav-open .site-nav {
    display: flex;
  }

  .site-nav .panel-tab {
    width: 100%;
    text-align: left;
  }

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

  .toc-card {
    max-height: none;
  }

  .toc-toggle {
    display: inline-flex;
  }

  .toc-card.is-collapsed .toc-links {
    display: none;
  }

  .manual-toc {
    position: static;
  }

}

@media (max-width: 720px) {
  .site-header {
    padding-top: 10px;
  }

  .site-header-inner {
    padding: 12px;
    border-radius: 18px;
  }

  .hero {
    padding: 24px;
  }

  .brand-strip {
    align-items: flex-start;
  }

  .brand-icon {
    width: 56px;
    height: 56px;
  }

  .hero h1 {
    max-width: none;
  }

  .site-panels {
    padding: 12px;
  }

  .panel-nav {
    border-radius: 22px;
  }

  .manual-article,
  .overview-card,
  .spotlight-panel,
  .faq-group,
  .contact-card {
    padding: 20px;
  }

  .contact-meta {
    grid-template-columns: 1fr;
  }

  .site-footer {
    padding: 16px 18px;
    justify-content: center;
  }

  .back-to-top {
    right: 16px;
    bottom: 16px;
    width: 48px;
    height: 48px;
  }
}