:root {
  --color-bg-deep: #05060f;
  --color-bg: #0b1224;
  --color-surface: rgba(20, 30, 52, 0.85);
  --color-surface-strong: rgba(14, 22, 42, 0.95);
  --color-surface-soft: rgba(255, 255, 255, 0.04);
  --color-border: rgba(214, 176, 72, 0.25);
  --color-border-strong: rgba(214, 176, 72, 0.45);
  --color-accent: #d6b048;
  --color-accent-strong: #f6d97c;
  --color-text: #f0e6d2;
  --color-text-muted: #c9b896;
  --color-text-subtle: rgba(201, 184, 150, 0.75);
  --color-heading: #ffe8a3;
  --color-danger: #f37373;
  --shadow-soft: 0 30px 60px rgba(2, 6, 16, 0.4);
  --shadow-card: 0 20px 45px rgba(3, 8, 20, 0.28);
  --shadow-hover: 0 25px 70px rgba(4, 12, 30, 0.45);
  --font-serif: "Noto Serif TC", "Songti TC", "STSong", serif;
  --font-sans: "Noto Sans TC", "Source Han Sans", "PingFang TC", "Heiti TC", sans-serif;
  --font-mono: "JetBrains Mono", "Fira Code", monospace;
  --content-max-width: 1200px;
  --content-narrow-width: 860px;
  --header-height: 68px;
  --transition-base: 220ms ease;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-serif);
  background: radial-gradient(circle at top, rgba(28, 44, 82, 0.65) 0%, rgba(9, 12, 24, 0.92) 45%, #04050b 100%);
  color: var(--color-text);
  line-height: 1.85;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  position: relative;
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  background: url("../img/starfield.png"), radial-gradient(circle at 20% -10%, rgba(255, 215, 0, 0.15), transparent 60%), radial-gradient(circle at 80% 10%, rgba(114, 203, 255, 0.14), transparent 55%);
  background-size: cover, 100% 100%, 100% 100%;
  opacity: 0.24;
  pointer-events: none;
  z-index: -2;
}

body::after {
  content: "";
  position: fixed;
  inset: 0;
  background: linear-gradient(145deg, rgba(5, 6, 15, 0.88) 0%, rgba(12, 16, 32, 0.92) 55%, rgba(7, 8, 18, 0.88) 100%);
  z-index: -1;
}

a {
  color: inherit;
  text-decoration: none;
}

a:hover,
a:focus-visible {
  color: var(--color-accent-strong);
}

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

.skip-link {
  position: absolute;
  left: 50%;
  transform: translate(-50%, -120%);
  background: var(--color-accent);
  color: #0e0f1a;
  padding: 0.75rem 1.5rem;
  border-radius: 0 0 0.75rem 0.75rem;
  font-family: var(--font-sans);
  font-weight: 600;
  z-index: 1000;
  transition: transform var(--transition-base);
}

.skip-link:focus {
  transform: translate(-50%, 0);
}

.site-header {
  position: sticky;
  top: 0;
  backdrop-filter: blur(18px);
  background: linear-gradient(90deg, rgba(5, 6, 15, 0.92) 0%, rgba(10, 14, 28, 0.82) 50%, rgba(5, 6, 15, 0.88) 100%);
  border-bottom: 1px solid var(--color-border);
  z-index: 50;
  height: var(--header-height);
}

.site-header__inner {
  max-width: var(--content-max-width);
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 1.5rem;
  height: 100%;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.75rem;
  font-family: var(--font-sans);
  font-variant: small-caps;
  font-size: 0.95rem;
  letter-spacing: 0.35rem;
}

.brand__mark {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  border: 2px solid var(--color-border-strong);
  display: grid;
  place-items: center;
  background: radial-gradient(circle at 30% 20%, rgba(214, 176, 72, 0.45), rgba(8, 12, 26, 0.9));
  box-shadow: inset 0 0 18px rgba(246, 217, 124, 0.35), 0 12px 25px rgba(0, 0, 0, 0.35);
  position: relative;
  overflow: hidden;
  background-size: cover;
  background-position: center;
}

.brand__mark::after {
  content: "--";
  font-family: var(--font-serif);
  font-size: 1.25rem;
  color: var(--color-heading);
  transform: scaleX(0.8);
}

.nav-toggle {
  display: none;
  border: 1px solid var(--color-border);
  background: var(--color-surface-soft);
  color: var(--color-text);
  border-radius: 0.75rem;
  padding: 0.5rem 0.75rem;
  cursor: pointer;
  font-family: var(--font-sans);
  font-size: 0.95rem;
  transition: all var(--transition-base);
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
}

.nav-toggle[aria-expanded="true"] {
  color: var(--color-accent-strong);
  border-color: var(--color-border-strong);
}

.nav-toggle__icon {
  position: relative;
  width: 1.4rem;
  height: 0.125rem;
  border-radius: 999px;
  background: var(--color-heading);
  transition: background var(--transition-base), transform var(--transition-base);
}

.nav-toggle__icon::before,
.nav-toggle__icon::after {
  content: "";
  position: absolute;
  left: 0;
  width: 100%;
  height: 100%;
  border-radius: 999px;
  background: var(--color-heading);
  transition: transform var(--transition-base);
}

.nav-toggle__icon::before {
  transform: translateY(-0.4rem);
}

.nav-toggle__icon::after {
  transform: translateY(0.4rem);
}

.nav-toggle__label {
  font-family: var(--font-sans);
  font-size: 0.85rem;
  letter-spacing: 0.2rem;
  text-transform: uppercase;
}

.nav-toggle.is-active .nav-toggle__icon {
  background: transparent;
}

.nav-toggle.is-active .nav-toggle__icon::before {
  transform: translateY(0) rotate(45deg);
}

.nav-toggle.is-active .nav-toggle__icon::after {
  transform: translateY(0) rotate(-45deg);
}

.primary-nav__list {
  list-style: none;
  display: flex;
  align-items: center;
  gap: 2.5rem;
  font-family: var(--font-sans);
  font-size: 0.9rem;
  letter-spacing: 0.1rem;
}

.primary-nav__link {
  position: relative;
  padding: 0.25rem 0;
}

.primary-nav__link::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -0.35rem;
  width: 0;
  height: 2px;
  background: linear-gradient(90deg, rgba(246, 217, 124, 0.9), rgba(221, 178, 70, 0.65));
  transition: width var(--transition-base);
}

.primary-nav__link:hover::after,
.primary-nav__link:focus-visible::after,
.primary-nav__link.is-active::after {
  width: 100%;
}

.site-header__actions {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  border: 0;
}

.lang-switcher {
  display: inline-flex;
  align-items: center;
  gap: 0.15rem;
  border: 1px solid var(--color-border);
  border-radius: 999px;
  padding: 0.2rem;
  background: rgba(5, 8, 18, 0.7);
  white-space: nowrap;
}

.lang-switcher button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border: none;
  background: transparent;
  color: var(--color-text-muted);
  font-family: var(--font-sans);
  font-size: 0.85rem;
  letter-spacing: 0.05rem;
  padding: 0.45rem 0.95rem;
  border-radius: 999px;
  cursor: pointer;
  transition: all var(--transition-base);
  line-height: 1;
  min-width: 3.25rem;
}

.lang-switcher button:hover,
.lang-switcher button:focus-visible {
  color: var(--color-accent-strong);
}

.lang-switcher button.is-active {
  background: var(--color-surface-soft);
  color: var(--color-heading);
  border: 1px solid var(--color-border-strong);
  box-shadow: inset 0 0 12px rgba(214, 176, 72, 0.18);
}

.lang-switcher--mobile {
  display: none;
  width: 100%;
  margin-top: 1.5rem;
  justify-content: center;
  flex-wrap: wrap;
  gap: 0.35rem;
}

.lang-switcher--mobile button {
  flex: 1 1 calc(50% - 0.35rem);
  min-width: 0;
}

.brand__mark img {
  width: 100%;
  height: 100%;
  object-fit: contain;
  display: block;
}

.brand__mark--image {
  border: none;
  box-shadow: none;
  background: transparent;
}

.brand__mark--image::after {
  content: none;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.75rem 1.5rem;
  border-radius: 999px;
  font-family: var(--font-sans);
  font-weight: 600;
  letter-spacing: 0.12rem;
  border: 1px solid transparent;
  transition: all var(--transition-base);
}

.btn--primary {
  background: linear-gradient(135deg, rgba(214, 176, 72, 0.95), rgba(246, 217, 124, 0.95));
  color: #1b1202;
  box-shadow: 0 18px 30px rgba(214, 176, 72, 0.35);
}

.btn--primary:hover,
.btn--primary:focus-visible {
  transform: translateY(-2px);
  box-shadow: 0 26px 45px rgba(246, 217, 124, 0.45);
}

.btn--ghost {
  border-color: var(--color-border);
  color: var(--color-heading);
  background: rgba(10, 14, 28, 0.6);
}

.btn--ghost:hover,
.btn--ghost:focus-visible {
  border-color: var(--color-border-strong);
  color: var(--color-accent-strong);
  box-shadow: inset 0 0 20px rgba(214, 176, 72, 0.15);
}

main {
  flex: 1;
}

.section {
  padding: 6.5rem 1.5rem 5.5rem;
}

.section__inner {
  max-width: var(--content-max-width);
  margin: 0 auto;
}

.section__header {
  max-width: var(--content-narrow-width);
  margin: 0 auto 3rem;
  text-align: center;
}

.eyebrow {
  font-family: var(--font-sans);
  font-size: 0.85rem;
  letter-spacing: 0.6rem;
  text-transform: uppercase;
  color: var(--color-accent-strong);
  margin-bottom: 1rem;
}

.section__title {
  font-size: clamp(2rem, 2.6vw, 3rem);
  letter-spacing: 0.35rem;
  color: var(--color-heading);
  margin-bottom: 1.2rem;
  text-transform: uppercase;
}

.section__subtitle {
  color: var(--color-text-muted);
  font-family: var(--font-sans);
  font-size: 1rem;
  letter-spacing: 0.08rem;
}

.hero {
  position: relative;
  padding: 9rem 1.5rem 6.5rem;
}

.hero__inner {
  max-width: var(--content-max-width);
  margin: 0 auto;
  display: grid;
  gap: 3rem;
  grid-template-columns: repeat(12, 1fr);
}

.hero__content {
  grid-column: span 7;
  padding: 2.5rem;
  border-radius: 1.75rem;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  box-shadow: var(--shadow-soft);
}

.hero__title {
  font-size: clamp(2.8rem, 3.2vw, 4rem);
  letter-spacing: 0.45rem;
  color: var(--color-heading);
  margin-bottom: 1.4rem;
  text-transform: uppercase;
}

.hero__subtitle {
  font-family: var(--font-sans);
  font-size: 1.05rem;
  color: var(--color-text-muted);
  margin-bottom: 2.3rem;
  letter-spacing: 0.08rem;
}

.hero__embed {
  display: none;
  margin-bottom: 2rem;
  border-radius: 1rem;
  border: 1px solid var(--color-border);
  overflow: hidden;
  box-shadow: var(--shadow-soft);
  background: rgba(8, 12, 26, 0.75);
}

.hero__embed iframe {
  display: block;
  width: 100%;
  border: 0;
  min-height: 152px;
}

.hero__embed.is-active {
  display: block;
}

.hero__cta {
  display: inline-flex;
  gap: 1.25rem;
  flex-wrap: wrap;
}

.hero__aside {
  grid-column: span 5;
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.hero__card {
  background: var(--color-surface-strong);
  border: 1px solid var(--color-border);
  border-radius: 1.5rem;
  padding: 1.75rem;
  box-shadow: var(--shadow-soft);
}

.hero__card h3 {
  font-size: 1.1rem;
  letter-spacing: 0.22rem;
  margin-bottom: 0.8rem;
  color: var(--color-heading);
}

.hero__card p {
  font-family: var(--font-sans);
  color: var(--color-text-subtle);
  font-size: 0.95rem;
  letter-spacing: 0.05rem;
}

.pillars__grid {
  display: grid;
  gap: 1.5rem;
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.pillar-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 1.5rem;
  padding: 2.25rem 2rem;
  box-shadow: var(--shadow-card);
  transition: transform var(--transition-base), box-shadow var(--transition-base), border-color var(--transition-base);
  position: relative;
  overflow: hidden;
}

.pillar-card::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, rgba(214, 176, 72, 0.12), rgba(12, 18, 36, 0));
  opacity: 0;
  transition: opacity var(--transition-base);
}

.pillar-card:hover {
  transform: translateY(-6px);
  border-color: var(--color-border-strong);
  box-shadow: var(--shadow-hover);
}

.pillar-card:hover::after {
  opacity: 1;
}

.pillar-card h3 {
  font-size: 1.3rem;
  color: var(--color-heading);
  letter-spacing: 0.2rem;
  margin-bottom: 0.9rem;
  position: relative;
  z-index: 1;
}

.pillar-card p {
  font-family: var(--font-sans);
  color: var(--color-text-subtle);
  font-size: 0.95rem;
  letter-spacing: 0.05rem;
  position: relative;
  z-index: 1;
}

.story {
  position: relative;
  padding: 6rem 1.5rem 5rem;
}

.story__inner {
  max-width: var(--content-narrow-width);
  margin: 0 auto;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 2rem;
  padding: 3rem 3.5rem;
  box-shadow: var(--shadow-soft);
}

.story__inner p + p {
  margin-top: 1.2rem;
}

.story__inner blockquote {
  margin: 2.4rem 0;
  padding: 1.6rem 1.8rem;
  border-left: 3px solid var(--color-border-strong);
  background: rgba(8, 12, 26, 0.55);
  color: var(--color-heading);
  font-style: italic;
  letter-spacing: 0.08rem;
}

.chapters {
  position: relative;
  padding: 6.5rem 1.5rem 6rem;
}

.chapters::before {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(180deg, rgba(214, 176, 72, 0.07) 0%, rgba(9, 12, 24, 0) 45%, rgba(246, 217, 124, 0.04) 100%);
  opacity: 0.8;
  pointer-events: none;
}

.chapters__parts {
  display: grid;
  gap: 3rem;
  max-width: var(--content-max-width);
  margin: 0 auto;
  position: relative;
  z-index: 1;
}

.part-card {
  background: rgba(8, 12, 26, 0.82);
  border: 1px solid var(--color-border);
  border-radius: 2rem;
  padding: 2.75rem;
  box-shadow: var(--shadow-card);
}

.part-card__header {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
  margin-bottom: 2rem;
}

.part-card__eyebrow {
  font-family: var(--font-sans);
  letter-spacing: 0.4rem;
  font-size: 0.78rem;
  color: var(--color-accent);
  text-transform: uppercase;
}

.part-card__title {
  font-size: 1.8rem;
  color: var(--color-heading);
  letter-spacing: 0.25rem;
}

.part-card__description {
  font-family: var(--font-sans);
  color: var(--color-text-subtle);
  font-size: 0.95rem;
  letter-spacing: 0.06rem;
  margin-bottom: 1.6rem;
}

.chapter-grid {
  display: grid;
  gap: 1.75rem;
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.chapter-card {
  border: 1px solid var(--color-border);
  border-radius: 1.5rem;
  padding: 1.9rem;
  background: rgba(14, 22, 42, 0.88);
  display: flex;
  flex-direction: column;
  gap: 1rem;
  transition: border-color var(--transition-base), transform var(--transition-base), box-shadow var(--transition-base);
}

.chapter-card:hover {
  border-color: var(--color-border-strong);
  transform: translateY(-4px);
  box-shadow: var(--shadow-hover);
}

.chapter-card__title {
  font-size: 1.3rem;
  color: var(--color-heading);
  letter-spacing: 0.22rem;
}

.chapter-card__summary {
  font-family: var(--font-sans);
  color: var(--color-text-subtle);
  font-size: 0.95rem;
  letter-spacing: 0.05rem;
}

.chapter-card__excerpt {
  font-size: 0.95rem;
  color: var(--color-text-muted);
  letter-spacing: 0.06rem;
  border-left: 3px solid rgba(214, 176, 72, 0.35);
  padding-left: 1rem;
  font-style: italic;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  border: 0;
}

.chapters__loading {
  margin: 2.5rem auto 0;
  width: 72px;
  height: 72px;
  border-radius: 50%;
  border: 4px solid rgba(214, 176, 72, 0.25);
  border-top-color: rgba(246, 217, 124, 0.9);
  animation: spin 1s linear infinite;
  display: none;
}

.chapters__loading.is-active {
  display: block;
}

@keyframes spin {
  to {
    transform: rotate(360deg);
  }
}

.cta {
  padding: 6rem 1.5rem 7rem;
}

.cta__inner {
  max-width: var(--content-max-width);
  margin: 0 auto;
  border-radius: 2.5rem;
  padding: 3.5rem;
  background: radial-gradient(circle at top left, rgba(214, 176, 72, 0.14), rgba(8, 12, 24, 0.95));
  border: 1px solid var(--color-border);
  box-shadow: var(--shadow-soft);
  text-align: center;
}

.cta__title {
  font-size: clamp(2rem, 2.8vw, 3rem);
  letter-spacing: 0.4rem;
  color: var(--color-heading);
  margin-bottom: 1.5rem;
}

.cta__subtitle {
  font-family: var(--font-sans);
  font-size: 1.05rem;
  color: var(--color-text-muted);
  margin-bottom: 2.5rem;
  letter-spacing: 0.08rem;
}

.cta__actions {
  display: inline-flex;
  gap: 1.2rem;
  flex-wrap: wrap;
  justify-content: center;
}

.site-footer {
  padding: 2.5rem 1.5rem 3rem;
  background: rgba(6, 8, 18, 0.95);
  border-top: 1px solid var(--color-border);
}

.site-footer__inner {
  max-width: var(--content-max-width);
  margin: 0 auto;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
}

.footer__meta {
  font-family: var(--font-sans);
  color: var(--color-text-subtle);
  font-size: 0.85rem;
}

.footer__links {
  display: inline-flex;
  gap: 1.25rem;
  font-family: var(--font-sans);
  font-size: 0.85rem;
  color: var(--color-text-muted);
}

.footer__links a:hover,
.footer__links a:focus-visible {
  color: var(--color-accent-strong);
}

[data-animate] {
  opacity: 0;
  transform: translateY(40px);
  transition: opacity 0.8s ease, transform 0.8s ease;
}

[data-animate].is-visible {
  opacity: 1;
  transform: translateY(0);
}

@media (max-width: 1080px) {
  .hero__inner {
    grid-template-columns: repeat(1, minmax(0, 1fr));
  }

  .hero__content,
  .hero__aside {
    grid-column: 1 / -1;
  }

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

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

@media (max-width: 880px) {
  .site-header__actions {
    gap: 0.5rem;
  }

  .lang-switcher--desktop {
    display: none;
  }

  .lang-switcher--mobile {
    display: flex;
  }
}

@media (max-width: 768px) {
  :root {
    --header-height: 64px;
  }

  .site-header__inner {
    padding: 0 1.1rem;
    gap: 0.75rem;
  }

  .nav-toggle {
    display: inline-flex;
    margin-left: auto;
    background: rgba(8, 12, 26, 0.86);
    border-color: var(--color-border-strong);
    padding: 0.45rem 0.85rem;
  }

  .primary-nav {
    position: fixed;
    inset: var(--header-height) 0 auto 0;
    background: rgba(6, 8, 18, 0.98);
    backdrop-filter: blur(22px);
    border-bottom: 1px solid var(--color-border);
    transform: translateY(-120%);
    transition: transform var(--transition-base), opacity var(--transition-base);
    opacity: 0;
    z-index: 60;
  }

  .primary-nav.is-open {
    transform: translateY(0);
    opacity: 1;
  }

  .primary-nav__list {
    flex-direction: column;
    align-items: flex-start;
    padding: 1.5rem;
    gap: 1.25rem;
  }

  .site-header__actions {
    margin-left: auto;
  }

  .hero__content {
    padding: 2rem;
  }

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

  .section {
    padding-inline: 1.25rem;
  }

  .cta__inner {
    padding: 2.75rem 2rem;
  }

  body::before {
    opacity: 0.18;
  }
}

@media (max-width: 540px) {
  html {
    font-size: 15px;
  }

  .hero__cta,
  .cta__actions {
    width: 100%;
  }

  .btn {
    width: 100%;
  }

  .story__inner {
    padding: 2.4rem 2rem;
  }

  .part-card {
    padding: 2.2rem;
  }
}