:root {
  --color-bg-primary: #121820;
  --color-bg-secondary: #1B222C;
  --color-surface: #232B36;
  --color-text-primary: #E6EDF3;
  --color-text-secondary: #9AA5B1;
  --color-accent-cyan: #00B8D4;
  --color-accent-orange: #FF7A00;
  --color-accent-purple: #7B61FF;
  --color-border-glass: rgba(255,255,255,0.1);
  --color-overlay-glass: rgba(18,24,32,0.8);
  --header-w: 280px;
  --header-h: 64px;
  --container-max: 1280px;
  --radius: 8px;
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
  --font-sans: "Inter", "PingFang SC", "Microsoft YaHei", sans-serif;
}

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

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-height: 100vh;
  padding-top: var(--header-h);
  font-family: var(--font-sans);
  color: var(--color-text-primary);
  line-height: 1.6;
  background:
    linear-gradient(rgba(255,255,255,0.022) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,0.022) 1px, transparent 1px),
    radial-gradient(circle at 85% 12%, rgba(0,184,212,0.14), transparent 28rem),
    radial-gradient(circle at 12% 80%, rgba(123,97,255,0.10), transparent 24rem),
    var(--color-bg-primary);
  background-size: 72px 72px, 72px 72px, auto, auto, auto;
  background-attachment: fixed;
  -webkit-font-smoothing: antialiased;
}

#main-content {
  display: block;
  scroll-margin-top: calc(var(--header-h) + 12px);
}

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

button {
  font: inherit;
}

:focus-visible {
  outline: 2px solid var(--color-accent-orange);
  outline-offset: 4px;
  border-radius: 2px;
}

::selection {
  background: rgba(0,184,212,0.35);
  color: #ffffff;
}

.skip-link {
  position: fixed;
  top: 12px;
  left: 12px;
  z-index: 2000;
  padding: 12px 16px;
  background: var(--color-accent-cyan);
  color: #001014;
  font-weight: 700;
  text-decoration: none;
  border-radius: var(--radius);
  transform: translateY(-200%);
  transition: transform 0.3s var(--ease);
}

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

.container {
  width: min(calc(100% - 40px), var(--container-max));
  margin-inline: auto;
}

.container--narrow {
  max-width: 860px;
}

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

.section--tight {
  padding-block: clamp(2rem, 4vw, 3rem);
}

.section__header {
  display: flex;
  align-items: baseline;
  gap: 16px;
  margin-bottom: clamp(2rem, 5vw, 4rem);
}

.section__index {
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.22em;
  color: var(--color-accent-cyan);
}

.section__title {
  margin: 0;
  font-size: clamp(2rem, 5vw, 3.5rem);
  font-weight: 200;
  letter-spacing: -0.03em;
  line-height: 1.15;
  color: var(--color-text-primary);
}

.section__subtitle {
  max-width: 42em;
  margin: 16px 0 0;
  color: var(--color-text-secondary);
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 20px;
  border: 1px solid transparent;
  border-radius: var(--radius);
  font-weight: 600;
  text-decoration: none;
  cursor: pointer;
  transition: transform 0.25s var(--ease), background 0.25s, border-color 0.25s, color 0.25s;
}

.btn:hover {
  transform: translateY(-2px);
}

.btn--primary {
  background: var(--color-accent-cyan);
  border-color: var(--color-accent-cyan);
  color: #001014;
}

.btn--orange {
  background: var(--color-accent-orange);
  border-color: var(--color-accent-orange);
  color: #1a0d00;
}

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

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

.btn[disabled] {
  opacity: 0.5;
  pointer-events: none;
}

.breadcrumb__list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  list-style: none;
  margin: 0 0 24px;
  padding: 0;
  font-size: 13px;
  color: var(--color-text-secondary);
}

.breadcrumb__item + .breadcrumb__item::before {
  content: "/";
  margin-right: 8px;
  color: var(--color-text-secondary);
  opacity: 0.6;
}

.breadcrumb__link {
  color: var(--color-accent-cyan);
  text-decoration: none;
}

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

.breadcrumb__current {
  color: var(--color-text-primary);
}

.grid {
  display: grid;
  gap: 24px;
}

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

.card {
  background: var(--color-surface);
  border: 1px solid var(--color-border-glass);
  border-radius: 12px;
  padding: 24px;
  transition: transform 0.3s var(--ease), border-color 0.3s;
}

.card:hover {
  transform: translateY(-4px);
  border-color: rgba(0,184,212,0.4);
}

.card__title {
  margin: 0 0 8px;
  font-size: 1.125rem;
  font-weight: 650;
  color: var(--color-text-primary);
}

.card__text {
  margin: 0;
  font-size: 0.9375rem;
  color: var(--color-text-secondary);
}

.media {
  position: relative;
  overflow: hidden;
  aspect-ratio: 16 / 9;
  background: var(--color-bg-secondary);
  border: 1px solid var(--color-border-glass);
  border-radius: 12px;
}

.media--4-3 {
  aspect-ratio: 4 / 3;
}

.media--1-1 {
  aspect-ratio: 1 / 1;
}

.media--portrait {
  aspect-ratio: 3 / 4;
}

.media img,
.media__placeholder {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.media__placeholder {
  display: grid;
  place-items: center;
  font-size: 12px;
  letter-spacing: 0.2em;
  color: var(--color-text-secondary);
  background: linear-gradient(135deg, rgba(0,184,212,0.08), rgba(123,97,255,0.08));
}

.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 10px;
  border-radius: 999px;
  background: rgba(0,184,212,0.08);
  color: var(--color-accent-cyan);
  font-size: 12px;
  letter-spacing: 0.08em;
}

.tag--orange {
  background: rgba(255,122,0,0.10);
  color: var(--color-accent-orange);
}

.site-header {
  position: fixed;
  top: 0;
  left: 0;
  z-index: 1000;
  width: 100%;
  height: var(--header-h);
  background: rgba(18,24,32,0.82);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--color-border-glass);
}

.site-header__inner {
  position: relative;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 0 20px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  color: var(--color-text-primary);
  text-decoration: none;
}

.brand__index {
  flex-shrink: 0;
  padding: 2px 8px;
  border: 1px solid rgba(0,184,212,0.3);
  border-radius: var(--radius);
  background: rgba(0,184,212,0.08);
  color: var(--color-accent-cyan);
  font-size: 28px;
  font-weight: 800;
  letter-spacing: -0.04em;
  line-height: 1.2;
}

.brand__lockup {
  display: grid;
  gap: 2px;
}

.brand__name {
  font-size: 1.125rem;
  font-weight: 700;
  letter-spacing: 0.02em;
  line-height: 1.2;
}

.brand__meta {
  font-size: 10px;
  letter-spacing: 0.28em;
  text-transform: uppercase;
  color: var(--color-text-secondary);
}

.nav-toggle {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 12px;
  border: 1px solid var(--color-border-glass);
  border-radius: 6px;
  background: transparent;
  color: var(--color-text-primary);
  cursor: pointer;
  transition: border-color 0.25s, color 0.25s;
}

.nav-toggle:hover {
  border-color: var(--color-accent-cyan);
  color: var(--color-accent-cyan);
}

.nav-toggle__icon {
  position: relative;
  width: 16px;
  height: 10px;
}

.nav-toggle__line {
  position: absolute;
  left: 0;
  width: 16px;
  height: 1.5px;
  background: currentColor;
  border-radius: 2px;
  transition: transform 0.25s var(--ease), top 0.25s var(--ease);
}

.nav-toggle__line:nth-child(1) {
  top: 0;
}

.nav-toggle__line:nth-child(2) {
  top: 8px;
}

.nav-toggle[aria-expanded="true"] .nav-toggle__line:nth-child(1) {
  top: 4px;
  transform: rotate(45deg);
}

.nav-toggle[aria-expanded="true"] .nav-toggle__line:nth-child(2) {
  top: 4px;
  transform: rotate(-45deg);
}

.nav-toggle__label {
  font-size: 12px;
  letter-spacing: 0.08em;
}

.site-nav {
  display: none;
  position: absolute;
  top: calc(100% + 8px);
  left: 16px;
  right: 16px;
  z-index: 100;
  padding: 14px;
  background: var(--color-bg-secondary);
  border: 1px solid var(--color-border-glass);
  border-radius: 12px;
  box-shadow: 0 24px 64px rgba(0,0,0,0.45);
}

.site-nav[data-open] {
  display: block;
  animation: navIn 0.35s var(--ease);
}

@keyframes navIn {
  from {
    opacity: 0;
    transform: translateY(-8px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.nav-list {
  display: grid;
  gap: 4px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.nav-list__item {
  margin: 0;
}

.nav-list__link {
  position: relative;
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding: 10px 8px;
  border-radius: 4px;
  color: var(--color-text-secondary);
  text-decoration: none;
  font-size: 14px;
  letter-spacing: 0.04em;
  transition: background 0.25s, color 0.25s, transform 0.25s var(--ease);
}

.nav-list__link:hover {
  background: rgba(0,184,212,0.08);
  color: var(--color-text-primary);
  transform: translateX(2px);
}

.nav-list__index {
  min-width: 24px;
  font-size: 10px;
  font-variant-numeric: tabular-nums;
  letter-spacing: 0.1em;
  color: var(--color-accent-cyan);
  opacity: 0.85;
}

.nav-list__label {
  font-weight: 500;
}

.nav-list__link[aria-current="page"] {
  color: var(--color-text-primary);
}

.nav-list__link[aria-current="page"]::before {
  content: "";
  position: absolute;
  left: 0;
  top: 18%;
  bottom: 18%;
  width: 2px;
  background: var(--color-accent-orange);
  border-radius: 2px;
}

.nav-list__link[aria-current="page"] .nav-list__index {
  color: var(--color-accent-orange);
  opacity: 1;
}

.header-action {
  display: none;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  width: 100%;
  padding: 12px 14px;
  border: 1px solid rgba(0,184,212,0.35);
  border-radius: var(--radius);
  background: rgba(0,184,212,0.10);
  color: var(--color-text-primary);
  text-decoration: none;
  font-size: 14px;
  font-weight: 600;
  letter-spacing: 0.04em;
  transition: background 0.25s, border-color 0.25s, transform 0.25s var(--ease);
}

.header-action:hover {
  background: rgba(0,184,212,0.18);
  border-color: var(--color-accent-cyan);
  transform: translateX(4px);
}

.header-action__label {
  display: block;
}

.header-action__arrow {
  color: var(--color-accent-cyan);
  font-size: 16px;
  line-height: 1;
  transition: color 0.2s;
}

.header-action:hover .header-action__arrow {
  color: var(--color-accent-orange);
}

.header-progress {
  display: none;
}

.header-progress__bar {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: calc(var(--reading-progress, 0) * 100%);
  background: linear-gradient(180deg, var(--color-accent-cyan), var(--color-accent-purple));
  box-shadow: 0 0 12px rgba(0,184,212,0.6);
}

.site-footer {
  padding: clamp(3rem, 7vw, 5rem) 0 1.5rem;
  background: var(--color-bg-secondary);
  border-top: 1px solid var(--color-border-glass);
}

.site-footer__inner {
  width: min(calc(100% - 40px), var(--container-max));
  margin-inline: auto;
}

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

.site-footer__brand .brand {
  margin-bottom: 18px;
}

.brand--footer .brand__index {
  font-size: 24px;
}

.site-footer__about {
  max-width: 34em;
  margin: 16px 0 0;
  color: var(--color-text-secondary);
}

.site-footer__heading {
  margin: 0 0 14px;
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--color-accent-cyan);
}

.site-footer__nav {
  display: grid;
}

.footer-links {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 6px;
}

.footer-links a {
  display: inline-block;
  padding: 4px 0;
  color: var(--color-text-secondary);
  text-decoration: none;
  font-size: 14px;
  transition: color 0.2s, padding-left 0.2s var(--ease);
}

.footer-links a:hover {
  color: var(--color-accent-cyan);
  padding-left: 6px;
}

.site-footer__contact-block {
  display: grid;
}

.site-footer__contact {
  display: grid;
  gap: 8px;
  font-style: normal;
  color: var(--color-text-secondary);
  font-size: 14px;
}

.site-footer__contact-line {
  display: block;
}

.site-footer__hours {
  margin: 12px 0 0;
  padding-left: 14px;
  border-left: 2px solid rgba(0,184,212,0.4);
  color: var(--color-text-secondary);
  font-size: 12px;
  opacity: 0.85;
}

.site-footer__coords {
  display: flex;
  flex-wrap: wrap;
  gap: 12px 24px;
  align-items: center;
  justify-content: flex-start;
  margin-top: 40px;
  padding-top: 16px;
  border-top: 1px solid var(--color-border-glass);
  font-family: ui-monospace, SFMono-Regular, Consolas, monospace;
  font-size: 11px;
  letter-spacing: 0.18em;
  color: var(--color-text-secondary);
}

.site-footer__coords span:first-child {
  color: var(--color-accent-cyan);
}

.site-footer__coords-mark {
  color: var(--color-accent-orange);
}

.site-footer__bottom {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 20px;
  align-items: center;
  justify-content: space-between;
  margin-top: 20px;
  font-size: 12px;
  color: var(--color-text-secondary);
}

.site-footer__bottom a {
  color: var(--color-text-secondary);
  text-decoration: none;
  transition: color 0.2s;
}

.site-footer__bottom a:hover {
  color: var(--color-accent-orange);
}

.site-footer__note {
  margin: 16px 0 0;
  padding-top: 16px;
  border-top: 1px solid var(--color-border-glass);
  font-size: 12px;
  line-height: 1.6;
  color: var(--color-text-secondary);
  opacity: 0.85;
}

@media (min-width: 640px) {
  .grid--2 {
    grid-template-columns: repeat(2, 1fr);
  }

  .site-footer__coords {
    justify-content: flex-end;
  }

  .site-footer__bottom {
    justify-content: space-between;
  }
}

@media (min-width: 700px) {
  .site-footer__top {
    grid-template-columns: 2fr 1fr 1.2fr;
    gap: 40px;
    align-items: start;
  }
}

@media (min-width: 960px) {
  body {
    padding-top: 0;
    padding-left: var(--header-w);
  }

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

  .site-header {
    width: var(--header-w);
    height: 100vh;
    min-height: 600px;
    border-right: 1px solid var(--color-border-glass);
    border-bottom: 0;
  }

  .site-header__inner {
    flex-direction: column;
    align-items: flex-start;
    justify-content: flex-start;
    gap: clamp(20px, 3.5vh, 36px);
    padding: 32px 20px 28px;
  }

  .brand {
    width: 100%;
  }

  .nav-toggle {
    display: none;
  }

  .site-nav,
  .site-nav[data-open] {
    display: block;
    position: static;
    width: 100%;
    padding: 0;
    background: transparent;
    border: 0;
    border-radius: 0;
    box-shadow: none;
    animation: none;
  }

  .nav-list {
    gap: 2px;
    border-left: 1px solid var(--color-border-glass);
    padding-left: 12px;
  }

  .nav-list__link {
    padding: 12px 8px;
  }

  .header-action {
    display: flex;
    margin-top: auto;
  }

  .header-progress {
    display: block;
    position: absolute;
    top: 0;
    right: 0;
    width: 2px;
    height: 100%;
    background: rgba(255,255,255,0.05);
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }

  .site-nav[data-open] {
    opacity: 1;
    transform: none;
  }
}