:root {
  --bg-primary: #1F2A44;
  --bg-secondary: #1A1A2E;
  --bg-dark: #141424;
  --accent-orange: #FF6B35;
  --accent-green: #C6FF00;
  --accent-purple: #3A2E5D;
  --accent-wine: #7A2E2E;
  --text-light: #E8E9ED;
  --text-muted: #AAB3C8;
  --line-color: #4A5A78;
  --font-display: Impact, Haettenschweiler, "Arial Narrow Bold", sans-serif;
  --font-mono: "JetBrains Mono", Consolas, "Courier New", monospace;
  --font-body: Inter, "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-serif: "Roboto Slab", Georgia, serif;
  --header-h: 72px;
  --container-w: 1280px;
  --space-section: clamp(3rem, 8vw, 6rem);
  --radius: 0;
}

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

html {
  scroll-behavior: smooth;
}

html:focus-within, html:focus, body:focus {
  outline: none;
}

body {
  font-family: var(--font-body);
  background: linear-gradient(135deg, var(--bg-primary) 0%, var(--bg-secondary) 55%, var(--bg-dark) 100%);
  color: var(--text-light);
  line-height: 1.6;
  min-height: 100vh;
  overflow-x: hidden;
}

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

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

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

ul, ol {
  list-style: none;
}

:focus-visible {
  outline: 3px solid var(--accent-green);
  outline-offset: 3px;
}

.skip-link {
  position: fixed;
  top: -100%;
  left: 1rem;
  z-index: 2000;
  background: var(--accent-orange);
  color: #fff;
  padding: 0.75rem 1.25rem;
  font-weight: 700;
  transition: top 0.2s ease;
}

.skip-link:focus {
  top: 0.75rem;
}

.container {
  width: min(100% - 2rem, var(--container-w));
  margin-inline: auto;
}

.section {
  padding-block: clamp(3rem, 8vw, 6rem);
  position: relative;
}

.section__header {
  display: flex;
  align-items: baseline;
  gap: 1rem;
  margin-bottom: 2rem;
  border-bottom: 1px solid var(--line-color);
  padding-bottom: 1rem;
}

.section__number {
  font-family: var(--font-mono);
  font-size: 2rem;
  color: var(--accent-orange);
  font-weight: 700;
  letter-spacing: -0.05em;
}

.section__title {
  font-family: var(--font-display);
  font-size: clamp(1.8rem, 4vw, 3rem);
  text-transform: uppercase;
  letter-spacing: 0.01em;
  line-height: 1.1;
  color: var(--text-light);
}

.section__description {
  font-family: var(--font-serif);
  font-size: 1.1rem;
  color: var(--text-muted);
  margin-left: auto;
  max-width: 28rem;
  text-align: right;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.75rem 1.5rem;
  font-weight: 700;
  font-family: var(--font-body);
  letter-spacing: 0.02em;
  line-height: 1;
  cursor: pointer;
  border: 2px solid transparent;
  transition: transform 0.2s ease, background 0.2s ease, color 0.2s ease, border-color 0.2s ease;
  clip-path: polygon(0 0, calc(100% - 10px) 0, 100% 10px, 100% 100%, 10px 100%, 0 calc(100% - 10px));
}

.btn--primary {
  background: var(--accent-orange);
  color: #fff;
}

.btn--primary:hover {
  background: #fff;
  color: var(--accent-orange);
}

.btn--ghost {
  background: transparent;
  border-color: var(--line-color);
  color: var(--text-light);
}

.btn--ghost:hover {
  border-color: var(--accent-green);
  color: var(--accent-green);
}

.btn--data {
  background: var(--accent-green);
  color: #1A1A2E;
}

.btn--data:hover {
  background: #fff;
}

.grid {
  display: grid;
  gap: 1.5rem;
}

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

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

.grid--4 {
  grid-template-columns: repeat(4, 1fr);
}

.data-card {
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid var(--line-color);
  padding: 1.5rem;
  position: relative;
  clip-path: polygon(0 0, calc(100% - 16px) 0, 100% 16px, 100% 100%, 16px 100%, 0 calc(100% - 16px));
  min-height: 120px;
}

.data-card::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, transparent 0%, transparent 70%, var(--accent-purple) 100%);
  opacity: 0.3;
  pointer-events: none;
}

.data-card__value {
  font-family: var(--font-mono);
  font-size: clamp(2rem, 5vw, 3.5rem);
  font-weight: 700;
  line-height: 1;
  color: var(--accent-green);
  letter-spacing: -0.03em;
}

.data-card__label {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-muted);
  margin-top: 0.5rem;
}

.data-card__trend--up {
  color: var(--accent-green);
}

.data-card__trend--down {
  color: var(--accent-orange);
}

.panel {
  background: rgba(255, 255, 255, 0.03);
  border: 1px solid var(--line-color);
  padding: 2rem;
  position: relative;
}

.panel--dark {
  background: rgba(0, 0, 0, 0.2);
  border-color: var(--accent-purple);
}

.panel--clipped {
  clip-path: polygon(0 0, calc(100% - 24px) 0, 100% 24px, 100% 100%, 24px 100%, 0 calc(100% - 24px));
}

.breadcrumb {
  padding-block: 1rem 0;
}

.breadcrumb__list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  font-family: var(--font-mono);
  font-size: 0.8rem;
}

.breadcrumb__item {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  color: var(--text-muted);
}

.breadcrumb__item:not(:last-child)::after {
  content: '/';
  color: var(--line-color);
}

.breadcrumb__link:hover {
  color: var(--accent-orange);
}

.page-title {
  font-family: var(--font-display);
  font-size: clamp(2.5rem, 7vw, 5rem);
  line-height: 1;
  text-transform: uppercase;
  letter-spacing: 0.01em;
  margin-block: 2rem 1rem;
  color: var(--text-light);
}

.page-intro {
  font-family: var(--font-serif);
  font-size: 1.25rem;
  color: var(--text-muted);
  max-width: 46rem;
  margin-bottom: 3rem;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: rgba(26, 26, 46, 0.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--line-color);
  height: var(--header-h);
  display: flex;
  align-items: center;
}

.header__inner {
  width: min(100% - 2rem, var(--container-w));
  margin-inline: auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.header__logo {
  display: inline-flex;
  align-items: center;
  gap: 0.75rem;
  font-family: var(--font-display);
  font-size: 1.75rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: #fff;
  white-space: nowrap;
}

.header__logo-mark {
  display: inline-grid;
  place-items: center;
  width: 44px;
  height: 44px;
  background: var(--accent-orange);
  color: #1A1A2E;
  font-size: 1.5rem;
  font-family: var(--font-mono);
  font-weight: 800;
  clip-path: polygon(0 0, 100% 0, 100% 70%, 70% 100%, 0 100%);
}

.header__logo-text {
  font-size: 1.25rem;
  letter-spacing: 0.1em;
}

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

.header__status {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-muted);
  border: 1px solid var(--line-color);
  padding: 0.35rem 0.6rem;
  white-space: nowrap;
  background: rgba(0,0,0,0.2);
}

.header__toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 44px;
  height: 44px;
  padding: 8px;
  border: 1px solid var(--line-color);
  cursor: pointer;
  background: transparent;
}

.header__toggle-bar {
  display: block;
  height: 2px;
  width: 100%;
  background: var(--text-light);
  transition: transform 0.2s ease, opacity 0.2s ease;
}

.header__nav {
  display: flex;
  align-items: center;
}

.nav__list {
  display: flex;
  gap: 0.25rem;
}

.nav__link {
  display: block;
  padding: 0.5rem 0.75rem;
  font-size: 0.95rem;
  font-weight: 500;
  letter-spacing: 0.02em;
  color: var(--text-light);
  position: relative;
  transition: color 0.2s ease, background 0.2s ease;
}

.nav__link:hover {
  color: var(--accent-green);
}

.nav__link[aria-current="page"] {
  color: var(--accent-orange);
  background: rgba(255, 107, 53, 0.1);
  clip-path: polygon(0 0, calc(100% - 8px) 0, 100% 8px, 100% 100%, 8px 100%, 0 calc(100% - 8px));
}

.site-footer {
  background: var(--bg-dark);
  border-top: 2px solid var(--line-color);
  padding: clamp(2.5rem, 5vw, 4rem) 0 2rem;
  margin-top: auto;
}

.footer__inner {
  width: min(100% - 2rem, var(--container-w));
  margin-inline: auto;
}

.footer__brand {
  margin-bottom: 3rem;
}

.footer__logo {
  font-family: var(--font-display);
  font-size: 2rem;
  color: #fff;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.footer__tagline {
  font-family: var(--font-serif);
  color: var(--text-muted);
  margin-top: 0.35rem;
}

.footer__info {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 2rem;
  padding-block: 1.5rem;
  border-top: 1px solid var(--line-color);
  border-bottom: 1px solid var(--line-color);
}

.footer__heading {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  text-transform: uppercase;
  color: var(--accent-orange);
  letter-spacing: 0.1em;
  margin-bottom: 0.75rem;
}

.footer__text {
  color: var(--text-muted);
  margin-bottom: 0.4rem;
  font-size: 0.9rem;
}

.footer__links {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
  margin-bottom: 1rem;
}

.footer__link {
  color: var(--text-light);
  font-size: 0.9rem;
  transition: color 0.2s ease;
}

.footer__link:hover {
  color: var(--accent-green);
}

.footer__icp {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-muted);
}

.footer__statement {
  margin-top: 1.5rem;
  padding: 0.75rem;
  background: rgba(58, 46, 93, 0.3);
  border-left: 3px solid var(--accent-green);
  color: var(--text-muted);
  font-size: 0.9rem;
}

.footer__copyright {
  margin-top: 1rem;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-muted);
  text-align: center;
}

.back-to-top {
  position: fixed;
  right: 1.5rem;
  bottom: 1.5rem;
  z-index: 900;
  display: grid;
  place-items: center;
  width: 48px;
  height: 48px;
  background: var(--accent-orange);
  color: #fff;
  font-size: 1.5rem;
  cursor: pointer;
  border: none;
  opacity: 0;
  visibility: hidden;
  transform: translateY(20px);
  transition: opacity 0.2s ease, transform 0.2s ease, background 0.2s ease;
  clip-path: polygon(0 0, 100% 0, 100% 70%, 70% 100%, 0 100%);
}

.back-to-top[data-visible] {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.back-to-top:hover {
  background: var(--accent-green);
  color: #1A1A2E;
}

.progress-bar {
  position: fixed;
  top: 0;
  left: 0;
  height: 4px;
  width: 100%;
  background: rgba(255,255,255,0.1);
  z-index: 2000;
  pointer-events: none;
}

.progress-bar::after {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  height: 100%;
  width: 0;
  background: linear-gradient(90deg, var(--accent-orange), var(--accent-green));
  will-change: width;
}

.live-clock {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-muted);
  border: 1px solid var(--line-color);
  padding: 0.5rem 0.75rem;
  display: inline-flex;
  gap: 0.5rem;
  align-items: center;
  background: rgba(0,0,0,0.2);
}

.live-clock::before {
  content: '';
  width: 8px;
  height: 8px;
  background: var(--accent-green);
  border-radius: 50%;
  animation: pulse 1.5s ease-in-out infinite;
}

@keyframes pulse {
  0%, 100% { box-shadow: 0 0 0 0 rgba(198,255,0,0.7); }
  50% { box-shadow: 0 0 0 8px rgba(198,255,0,0); }
}

@keyframes fadeSlideUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@media (max-width: 1024px) {
  .grid--4 {
    grid-template-columns: repeat(2, 1fr);
  }
  .header__status {
    display: none;
  }
}

@media (max-width: 768px) {
  .header__inner {
    width: 100%;
    padding-inline: 1rem;
  }

  .header__toggle {
    display: flex;
  }

  .header__nav {
    position: fixed;
    top: var(--header-h);
    left: 0;
    right: 0;
    background: var(--bg-secondary);
    border-bottom: 2px solid var(--accent-orange);
    padding: 1rem;
    transform: translateY(-120%);
    transition: transform 0.25s ease;
    z-index: 1000;
    display: block;
  }

  .header__nav[data-open] {
    transform: translateY(0);
  }

  .nav__list {
    flex-direction: column;
    gap: 0.5rem;
  }

  .nav__link {
    font-size: 1.1rem;
    padding: 0.75rem 0.5rem;
  }

  .nav__link[aria-current="page"] {
    background: rgba(255,107,53,0.15);
  }

  .footer__info {
    grid-template-columns: 1fr;
    gap: 1.5rem;
  }

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

  .section__header {
    flex-wrap: wrap;
  }

  .section__description {
    text-align: left;
    margin-left: 0;
  }
}

@media (max-width: 480px) {
  .header__logo-text {
    font-size: 1rem;
  }
  .header__logo-mark {
    width: 36px;
    height: 36px;
    font-size: 1.1rem;
  }
  .grid--4 {
    grid-template-columns: 1fr;
  }
  .panel {
    padding: 1.25rem;
  }
}

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

@media (prefers-reduced-motion: no-preference) {
  .chapter-preview__item:hover .data-card::after {
    transform: translateX(2px);
  }
}