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

* {
  margin: 0;
  padding: 0;
}

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
}

body {
  min-height: 100vh;
  line-height: 1.6;
  font-family: "Roboto", "PingFang SC", "Microsoft YaHei", sans-serif;
  font-weight: 300;
  color: var(--color-text);
  background-color: var(--color-space);
  background-image:
    linear-gradient(rgba(0, 229, 255, 0.035) 1px, transparent 1px),
    linear-gradient(90deg, rgba(0, 229, 255, 0.035) 1px, transparent 1px);
  background-size: 42px 42px;
}

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

button, input, textarea, select {
  font: inherit;
  color: inherit;
  background: none;
  border: none;
}

a {
  color: inherit;
}

ul, ol {
  list-style: none;
}

h1, h2, h3, h4, h5, h6 {
  font-size: inherit;
  font-weight: inherit;
}

h1, h2, h3, h4 {
  font-family: "Noto Sans SC", "HarmonyOS Sans", "PingFang SC", sans-serif;
  font-weight: 900;
  line-height: 1.1;
  letter-spacing: -0.02em;
  transform: skewX(-6deg);
  transform-origin: left bottom;
}

h1 {
  font-size: clamp(2.6rem, 8vw, 5rem);
}

h2 {
  font-size: clamp(2rem, 5vw, 3rem);
}

h3 {
  font-size: 1.5rem;
}

h4 {
  font-size: 1.15rem;
}

p {
  margin-bottom: 1rem;
}

:root {
  --color-space: #0B1B36;
  --color-deep: #081224;
  --color-surface: #102A4C;
  --color-neon: #C8FF00;
  --color-orange: #FF6B00;
  --color-text: #F2F6FC;
  --color-muted: #9FB3D1;
  --color-divider: #1E3A5F;
  --color-stream: #00E5FF;
  --font-heading: "Noto Sans SC", "HarmonyOS Sans", "PingFang SC", sans-serif;
  --font-body: "Roboto", "PingFang SC", "Microsoft YaHei", sans-serif;
  --header-height: 72px;
  --container-width: 1280px;
  --space-section: clamp(64px, 10vw, 128px);
}

#main-content,
[data-chapter] {
  scroll-margin-top: calc(var(--header-height) + 16px);
}

.container {
  width: min(100%, calc(var(--container-width) + 48px));
  margin-inline: auto;
  padding-inline: clamp(16px, 4vw, 48px);
}

.page-main {
  padding-top: var(--header-height);
  background: var(--color-space);
}

.section {
  padding-block: var(--space-section);
}

.section--tight {
  padding-block: clamp(32px, 5vw, 64px);
}

.section-head {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-end;
  gap: 24px;
  margin-bottom: 48px;
}

.section-title {
  color: var(--color-text);
}

.section-title__highlight {
  color: var(--color-neon);
}

.section-title__highlight--orange {
  color: var(--color-orange);
}

.section-index {
  font-family: var(--font-heading);
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.2em;
  color: var(--color-muted);
  border-left: 3px solid var(--color-orange);
  padding-left: 12px;
  align-self: flex-start;
  white-space: nowrap;
}

.section-desc {
  max-width: 64ch;
  color: var(--color-muted);
  font-size: 1rem;
  line-height: 1.8;
}

.text-muted {
  color: var(--color-muted);
}

.text-neon {
  color: var(--color-neon);
}

.text-orange {
  color: var(--color-orange);
}

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

.skip-link {
  position: fixed;
  top: 8px;
  left: 8px;
  z-index: 1000;
  background: var(--color-neon);
  color: var(--color-deep);
  padding: 8px 16px;
  font-weight: 700;
  text-decoration: none;
  transform: translateY(-200%);
  transition: transform 0.2s ease;
}

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

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 24px;
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 0.9rem;
  letter-spacing: 0.06em;
  text-decoration: none;
  text-transform: uppercase;
  border: 1px solid transparent;
  cursor: pointer;
  transform: skewX(-6deg);
  transition: background-color 0.3s ease, color 0.3s ease, transform 0.2s ease, box-shadow 0.3s ease;
}

.btn--primary {
  background: var(--color-neon);
  color: var(--color-deep);
}

.btn--primary:hover {
  background: var(--color-orange);
  color: #fff;
  box-shadow: 0 8px 32px rgba(255, 107, 0, 0.3);
}

.btn--outline {
  border-color: var(--color-orange);
  color: var(--color-orange);
}

.btn--outline:hover {
  background: var(--color-orange);
  color: var(--color-deep);
  box-shadow: 0 8px 32px rgba(255, 107, 0, 0.25);
}

.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 12px;
  font-size: 0.75rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  border-radius: 999px;
  border: 1px solid var(--color-divider);
  color: var(--color-muted);
}

.tag--neon {
  background: var(--color-neon);
  color: var(--color-deep);
  border-color: transparent;
  font-weight: 700;
}

.tag--orange {
  background: transparent;
  border-color: var(--color-orange);
  color: var(--color-orange);
}

.tag--ghost {
  background: rgba(255, 255, 255, 0.06);
  border-color: rgba(255, 255, 255, 0.1);
  color: var(--color-text);
}

.card {
  position: relative;
  background: var(--color-surface);
  border: 1px solid var(--color-divider);
  border-top: 3px solid var(--color-orange);
  padding: 28px;
  transition: transform 0.4s cubic-bezier(0.2, 0.8, 0.2, 1), box-shadow 0.4s ease;
}

.card:hover {
  transform: translateY(-6px);
  box-shadow: 0 20px 48px rgba(0, 0, 0, 0.35);
}

.card__title {
  font-size: 1.25rem;
  margin-bottom: 12px;
}

.card__body {
  color: var(--color-muted);
  font-size: 0.95rem;
  line-height: 1.7;
}

.card__footer {
  margin-top: 20px;
}

.card--tilt::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 4px;
  background: var(--color-neon);
}

.card--accent {
  border-top-color: var(--color-neon);
}

.data-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9rem;
  background: var(--color-surface);
}

.data-table th {
  text-align: left;
  padding: 12px 16px;
  background: var(--color-deep);
  color: var(--color-muted);
  font-weight: 500;
  letter-spacing: 0.06em;
  border-bottom: 2px solid var(--color-orange);
}

.data-table td {
  padding: 14px 16px;
  border-bottom: 1px solid var(--color-divider);
  color: var(--color-text);
}

.data-table__score {
  font-family: var(--font-heading);
  font-weight: 900;
  color: var(--color-neon);
  font-size: 1.1rem;
}

.data-table--hover tbody tr:hover {
  background: rgba(0, 229, 255, 0.06);
}

.visual-frame {
  position: relative;
  overflow: hidden;
  aspect-ratio: 16 / 9;
  background:
    linear-gradient(135deg, rgba(0, 229, 255, 0.16) 0%, transparent 60%),
    linear-gradient(315deg, rgba(255, 107, 0, 0.14) 0%, transparent 50%),
    var(--color-surface);
  border: 1px solid var(--color-divider);
}

.visual-frame::before {
  content: "";
  position: absolute;
  inset: 0;
  background:
    repeating-linear-gradient(90deg, transparent 0 24px, rgba(0, 229, 255, 0.06) 24px 25px),
    repeating-linear-gradient(0deg, transparent 0 24px, rgba(0, 229, 255, 0.06) 24px 25px);
  pointer-events: none;
}

.visual-frame--wide {
  aspect-ratio: 21 / 9;
}

.visual-frame--tilt {
  clip-path: polygon(0 3%, 100% 0, 100% 97%, 0 100%);
}

.grid-2 {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 32px;
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 32px;
}

.grid-sidebar {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 280px;
  gap: 48px;
  align-items: start;
}

.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  font-size: 0.85rem;
  color: var(--color-muted);
  padding: 20px 0;
}

.breadcrumb a {
  color: var(--color-muted);
  text-decoration: none;
  transition: color 0.2s;
}

.breadcrumb a:hover {
  color: var(--color-neon);
}

.breadcrumb__sep {
  color: var(--color-divider);
}

.hero-cover {
  min-height: 100vh;
  display: flex;
  align-items: center;
  position: relative;
  overflow: hidden;
  padding-top: var(--header-height);
  background:
    radial-gradient(ellipse at 75% 30%, rgba(0, 229, 255, 0.22), transparent 55%),
    radial-gradient(ellipse at 10% 90%, rgba(255, 107, 0, 0.15), transparent 45%),
    var(--color-space);
}

.hero-cover::before {
  content: "";
  position: absolute;
  top: -10%;
  left: -5%;
  width: 45%;
  height: 120%;
  background: var(--color-neon);
  opacity: 0.08;
  transform: skewX(-12deg);
}

.hero-cover::after {
  content: "";
  position: absolute;
  right: -10%;
  bottom: -10%;
  width: 60%;
  height: 80%;
  border: 1px solid rgba(0, 229, 255, 0.25);
  border-radius: 50%;
  transform: rotate(-15deg);
}

.hero-cover__inner {
  position: relative;
  z-index: 1;
  width: 100%;
}

.hero-cover__badge {
  margin-bottom: 16px;
}

.hero-cover__title {
  font-size: clamp(3rem, 9vw, 5rem);
  margin-bottom: 24px;
}

.hero-cover__lead {
  font-size: 1.25rem;
  max-width: 56ch;
  color: var(--color-muted);
  margin-bottom: 32px;
  line-height: 1.8;
}

.hero-cover__meta {
  display: flex;
  flex-wrap: wrap;
  gap: 24px;
  align-items: center;
  color: var(--color-muted);
  font-size: 0.85rem;
}

.scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  height: 3px;
  width: 0;
  background: var(--color-stream);
  box-shadow: 0 0 12px rgba(0, 229, 255, 0.6);
  z-index: 500;
  transition: width 0.12s linear;
}

.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 200;
  height: var(--header-height);
  background: transparent;
  border-bottom: 1px solid transparent;
  transition: background-color 0.45s ease, border-color 0.45s ease, box-shadow 0.45s ease;
}

.site-header.is-scrolled {
  background: rgba(8, 18, 36, 0.88);
  -webkit-backdrop-filter: blur(14px);
  backdrop-filter: blur(14px);
  border-bottom-color: var(--color-divider);
  box-shadow: 0 12px 40px rgba(0, 0, 0, 0.35);
}

.site-header__inner {
  height: 100%;
  max-width: calc(var(--container-width) + 48px);
  margin-inline: auto;
  padding-inline: clamp(16px, 4vw, 48px);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.site-brand {
  display: inline-flex;
  align-items: baseline;
  gap: 6px;
  font-family: var(--font-heading);
  font-weight: 900;
  font-size: 1.5rem;
  color: var(--color-text);
  text-decoration: none;
  letter-spacing: 0.02em;
  transform: skewX(-6deg);
  white-space: nowrap;
}

.site-brand__tag {
  font-size: 0.6rem;
  font-weight: 700;
  color: var(--color-neon);
  border: 1px solid currentColor;
  padding: 0.15em 0.4em;
  border-radius: 2px;
  letter-spacing: 0.12em;
}

.main-nav {
  height: 100%;
}

.main-nav__list {
  display: flex;
  align-items: center;
  gap: clamp(12px, 3vw, 28px);
  height: 100%;
}

.main-nav__link {
  position: relative;
  display: inline-flex;
  align-items: center;
  height: 100%;
  padding: 0 4px;
  font-size: 0.9rem;
  letter-spacing: 0.08em;
  color: var(--color-muted);
  text-decoration: none;
  transition: color 0.3s ease;
}

.main-nav__link::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: -2px;
  height: 2px;
  background: var(--color-neon);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.4s ease;
}

.main-nav__link:hover,
.main-nav__link:focus-visible {
  color: var(--color-text);
}

.main-nav__link:hover::after,
.main-nav__link[aria-current="page"]::after {
  transform: scaleX(1);
}

.main-nav__link[aria-current="page"] {
  color: var(--color-neon);
}

.header-refresh-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 12px;
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  color: var(--color-deep);
  background: var(--color-neon);
  border-radius: 999px;
  white-space: nowrap;
}

.header-refresh-badge::before {
  content: "";
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: currentColor;
  box-shadow: 0 0 8px currentColor;
  animation: pulse-dot 2s infinite;
}

@keyframes pulse-dot {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.35; }
}

.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 6px;
  width: 44px;
  height: 44px;
  padding: 10px;
  border: 1px solid var(--color-divider);
  border-radius: 4px;
  background: rgba(8, 18, 36, 0.4);
  cursor: pointer;
  transition: border-color 0.3s ease;
}

.nav-toggle:hover,
.nav-toggle:focus-visible {
  border-color: var(--color-neon);
}

.nav-toggle__bar {
  display: block;
  width: 100%;
  height: 2px;
  background: var(--color-text);
  transition: transform 0.3s ease, opacity 0.3s ease;
}

.nav-toggle[aria-expanded="true"] .nav-toggle__bar:nth-child(1) {
  transform: translateY(8px) rotate(45deg);
}

.nav-toggle[aria-expanded="true"] .nav-toggle__bar:nth-child(2) {
  opacity: 0;
}

.nav-toggle[aria-expanded="true"] .nav-toggle__bar:nth-child(3) {
  transform: translateY(-8px) rotate(-45deg);
}

body.nav-open {
  overflow: hidden;
}

.chapter-nav {
  position: fixed;
  right: clamp(12px, 3vw, 32px);
  top: 50%;
  transform: translateY(-50%);
  z-index: 120;
  max-width: 200px;
  padding: 16px;
  background: rgba(8, 18, 36, 0.82);
  -webkit-backdrop-filter: blur(10px);
  backdrop-filter: blur(10px);
  border: 1px solid var(--color-divider);
  border-left: 3px solid var(--color-neon);
  border-radius: 8px;
}

.chapter-nav:empty {
  display: none;
}

.chapter-nav__list {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.chapter-nav__item {
  margin: 0;
}

.chapter-nav__link {
  display: block;
  width: 100%;
  text-align: left;
  padding: 6px 8px;
  font-size: 0.75rem;
  letter-spacing: 0.04em;
  color: var(--color-muted);
  background: transparent;
  border: 0;
  border-left: 2px solid transparent;
  cursor: pointer;
  transition: color 0.3s ease, border-color 0.3s ease;
}

.chapter-nav__link:hover,
.chapter-nav__link.is-active {
  color: var(--color-neon);
  border-left-color: var(--color-neon);
}

.back-to-top {
  position: fixed;
  right: clamp(16px, 4vw, 32px);
  bottom: clamp(16px, 4vw, 32px);
  z-index: 150;
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--color-surface);
  border: 1px solid var(--color-divider);
  border-radius: 8px;
  color: var(--color-neon);
  font-size: 1.4rem;
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transform: translateY(16px) skewX(-6deg);
  transition: opacity 0.3s ease, visibility 0.3s ease, transform 0.3s ease, background-color 0.3s ease;
}

.back-to-top.is-visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0) skewX(-6deg);
}

.back-to-top:hover {
  background: var(--color-orange);
  color: var(--color-deep);
  border-color: var(--color-orange);
}

.site-footer {
  background: var(--color-deep);
  border-top: 4px solid var(--color-neon);
  color: var(--color-muted);
  font-size: 0.9rem;
  position: relative;
  z-index: 10;
}

.site-footer__main {
  max-width: calc(var(--container-width) + 48px);
  margin-inline: auto;
  padding: 64px clamp(16px, 4vw, 48px) 40px;
  display: grid;
  grid-template-columns: minmax(0, 2fr) 1fr 1fr minmax(0, 1.6fr);
  gap: 48px;
}

.footer-brand__name {
  font-family: var(--font-heading);
  font-weight: 900;
  font-size: 1.6rem;
  color: var(--color-text);
  transform: skewX(-6deg);
  margin-bottom: 8px;
}

.footer-brand__slogan {
  max-width: 28ch;
  color: var(--color-muted);
  line-height: 1.7;
}

.footer-col__title {
  font-size: 0.85rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--color-neon);
  margin-bottom: 16px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--color-divider);
}

.footer-links li + li {
  margin-top: 8px;
}

.footer-links a {
  color: var(--color-muted);
  text-decoration: none;
  transition: color 0.2s;
}

.footer-links a:hover {
  color: var(--color-orange);
}

.footer-contact li {
  display: flex;
  gap: 8px;
  line-height: 1.5;
  margin-bottom: 8px;
}

.footer-contact__key {
  flex-shrink: 0;
  min-width: 3em;
  color: var(--color-neon);
  font-size: 0.8rem;
}

.footer-contact__value {
  color: var(--color-muted);
}

.site-footer__bottom {
  max-width: calc(var(--container-width) + 48px);
  margin-inline: auto;
  padding: 24px clamp(16px, 4vw, 48px);
  border-top: 1px solid var(--color-divider);
  display: flex;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
}

.footer-trust {
  font-size: 0.8rem;
  color: var(--color-muted);
}

.footer-copyright {
  font-size: 0.8rem;
  color: var(--color-muted);
}

:focus-visible {
  outline: 2px solid var(--color-neon);
  outline-offset: 3px;
}

@media (max-width: 1024px) {
  .site-footer__main {
    grid-template-columns: 1fr 1fr;
  }

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

@media (max-width: 860px) {
  .nav-toggle {
    display: inline-flex;
  }

  .header-refresh-badge {
    display: none;
  }

  .main-nav {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: rgba(8, 18, 36, 0.98);
    border-bottom: 1px solid var(--color-divider);
    padding: 16px;
    height: auto;
    max-height: calc(100vh - var(--header-height));
    overflow-y: auto;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-8px);
    transition: opacity 0.3s ease, transform 0.3s ease, visibility 0.3s ease;
  }

  .main-nav[data-open="true"] {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
  }

  .main-nav__list {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    height: auto;
  }

  .main-nav__item + .main-nav__item {
    border-top: 1px solid rgba(30, 58, 95, 0.4);
  }

  .main-nav__link {
    height: auto;
    padding: 14px 8px;
    display: block;
  }

  .main-nav__link::after {
    display: none;
  }

  .chapter-nav {
    display: none;
  }
}

@media (max-width: 640px) {
  .site-brand__tag {
    display: none;
  }

  .grid-2,
  .grid-3 {
    grid-template-columns: 1fr;
  }

  .site-footer__main {
    grid-template-columns: 1fr;
    gap: 32px;
  }
}

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

  html {
    scroll-behavior: auto !important;
  }
}