:root {
  --arena-deep: #0B3D2E;
  --arena-pine: #145A45;
  --arena-moss: #2F7D5C;
  --arena-fern: #6DAF8F;
  --arena-gold: #D4AF37;
  --arena-gold-soft: #E8CE6A;
  --arena-ivory: #F4F1E8;
  --arena-paper: #FBFBF7;
  --arena-charcoal: #1E1E1E;
  --arena-slate: #4A4A4A;
  --font-display: "Inter Tight", "Noto Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-body: "Source Sans 3", "Noto Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-data: "JetBrains Mono", "SFMono-Regular", Consolas, "Liberation Mono", monospace;
  --container: 1280px;
  --gutter: clamp(16px, 4vw, 48px);
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: 8rem;
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  min-height: 100vh;
  background: var(--arena-paper);
  color: var(--arena-charcoal);
  font-family: var(--font-body);
  font-size: 1rem;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

body, h1, h2, h3, h4, h5, h6, p, ul, ol, figure, blockquote {
  margin: 0;
}

ul[class], ol[class] {
  list-style: none;
  padding: 0;
  margin: 0;
}

a {
  color: inherit;
}

button {
  font: inherit;
  border: 0;
  background: none;
  cursor: pointer;
}

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

h1, h2, h3, h4 {
  font-family: var(--font-display);
}

::selection {
  background: var(--arena-gold);
  color: var(--arena-charcoal);
}

:focus-visible {
  outline: 3px solid var(--arena-gold);
  outline-offset: 3px;
}

.skip-link {
  position: absolute;
  left: 1rem;
  top: -100px;
  z-index: 200;
  background: var(--arena-gold);
  color: var(--arena-charcoal);
  font-weight: 900;
  text-decoration: none;
  padding: .75rem 1rem;
  border: 1px solid var(--arena-charcoal);
}

.skip-link:focus {
  top: 1rem;
}

#main-content {
  scroll-margin-top: 8rem;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: linear-gradient(180deg, var(--arena-pine) 0%, var(--arena-deep) 100%);
  color: var(--arena-ivory);
  border-bottom: 1px solid var(--arena-gold);
  box-shadow: 0 6px 20px rgba(0, 0, 0, .22);
}

.masthead {
  max-width: var(--container);
  margin-inline: auto;
  padding: clamp(1rem, 2.8vw, 1.75rem) var(--gutter) .4rem;
  position: relative;
  text-align: center;
}

.masthead::before,
.masthead::after {
  content: "";
  position: absolute;
  top: 50%;
  width: 16%;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--arena-gold));
  opacity: .6;
}

.masthead::before {
  left: 1%;
}

.masthead::after {
  right: 1%;
  transform: scaleX(-1);
}

.masthead-brand {
  display: inline-flex;
  flex-direction: column;
  text-decoration: none;
  color: inherit;
}

.brand-kicker {
  display: block;
  font-family: var(--font-display);
  font-size: .72rem;
  font-weight: 900;
  letter-spacing: .24em;
  text-transform: uppercase;
  color: var(--arena-gold);
  margin-bottom: .3rem;
}

.brand-name {
  display: block;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(1.5rem, 4vw, 2.8rem);
  line-height: 1.05;
  letter-spacing: .08em;
}

.brand-name-en {
  display: block;
  font-family: var(--font-data);
  font-size: .68rem;
  letter-spacing: .34em;
  text-transform: uppercase;
  color: var(--arena-fern);
  margin-top: .3rem;
}

.masthead-tagline {
  margin-top: .4rem;
  font-weight: 700;
  letter-spacing: .18em;
  font-size: .78rem;
  color: var(--arena-fern);
}

.site-nav {
  max-width: var(--container);
  margin-inline: auto;
  padding: .25rem var(--gutter) 0;
  border-top: 1px solid rgba(244, 241, 232, .14);
}

.site-nav-list {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: clamp(.5rem, 2.6vw, 2rem);
}

.nav-link {
  display: inline-block;
  padding: .7rem .15rem;
  color: var(--arena-ivory);
  text-decoration: none;
  font-weight: 800;
  font-size: .9rem;
  letter-spacing: .1em;
  border-bottom: 2px solid transparent;
  transition: color .2s, border-color .2s;
}

.nav-link:hover {
  color: var(--arena-gold-soft);
}

.nav-link[aria-current="page"] {
  color: var(--arena-gold);
  border-bottom-color: var(--arena-gold);
}

.nav-toggle {
  display: none;
}

.reading-progress {
  position: absolute;
  bottom: -1px;
  left: 0;
  height: 3px;
  width: 0;
  background: linear-gradient(90deg, var(--arena-gold), var(--arena-gold-soft));
  z-index: 5;
}

.site-footer {
  background: linear-gradient(145deg, var(--arena-deep) 0%, var(--arena-pine) 55%, var(--arena-deep) 100%);
  color: var(--arena-ivory);
  border-top: 3px solid var(--arena-gold);
}

.footer-shell {
  max-width: var(--container);
  margin-inline: auto;
  padding: clamp(2.5rem, 6vw, 5rem) var(--gutter) 1.25rem;
  display: grid;
  grid-template-columns: 1.5fr 1fr 1fr 1.3fr;
  gap: clamp(1.5rem, 4vw, 3rem);
}

.footer-identity {
  align-self: start;
}

.footer-brand {
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(1.3rem, 2.5vw, 2rem);
  line-height: 1.1;
  letter-spacing: .06em;
}

.footer-tagline {
  margin-top: .35rem;
  color: var(--arena-gold);
  font-weight: 800;
  letter-spacing: .2em;
  font-size: .78rem;
  text-transform: uppercase;
}

.footer-about {
  margin-top: 1rem;
  color: var(--arena-fern);
  font-size: .9rem;
  line-height: 1.7;
  max-width: 34ch;
}

.footer-index,
.footer-files,
.footer-contact {
  align-self: start;
}

.footer-files {
  position: relative;
}

.footer-heading {
  font-family: var(--font-display);
  font-weight: 900;
  font-size: .78rem;
  letter-spacing: .18em;
  text-transform: uppercase;
  color: var(--arena-gold);
  border-bottom: 1px solid rgba(212, 175, 55, .35);
  padding-bottom: .5rem;
  margin-bottom: 1rem;
}

.footer-links {
  display: grid;
  gap: .55rem;
}

.footer-links a {
  color: var(--arena-ivory);
  text-decoration: none;
  font-weight: 600;
  transition: color .18s, padding-left .18s;
}

.footer-links a:hover {
  color: var(--arena-gold-soft);
  padding-left: .3rem;
}

.footer-contacts {
  display: grid;
  gap: .55rem;
}

.footer-contact-line {
  color: var(--arena-fern);
  font-size: .88rem;
  line-height: 1.5;
}

.footer-contact-line strong {
  display: block;
  color: var(--arena-ivory);
  font-weight: 800;
  letter-spacing: .04em;
}

.footer-trust {
  grid-column: 1 / -1;
  display: flex;
  gap: 1rem;
  align-items: flex-start;
  border: 1px solid rgba(212, 175, 55, .35);
  background: rgba(255, 255, 255, .04);
  padding: 1rem 1.25rem;
}

.footer-trust-label {
  flex: 0 0 auto;
  background: var(--arena-gold);
  color: var(--arena-charcoal);
  font-weight: 900;
  font-size: .7rem;
  letter-spacing: .14em;
  text-transform: uppercase;
  padding: .3rem .7rem;
}

.footer-trust p {
  margin: 0;
  color: var(--arena-ivory);
  font-size: .9rem;
}

.footer-bottom {
  grid-column: 1 / -1;
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: .75rem;
  border-top: 1px solid rgba(255, 255, 255, .12);
  padding-top: 1rem;
  color: var(--arena-fern);
  font-size: .85rem;
}

.footer-copy {
  color: var(--arena-ivory);
}

.footer-meta {
  letter-spacing: .05em;
}

.page-shell {
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.page-main {
  padding-block: clamp(2rem, 6vw, 4rem);
}

.section {
  margin-bottom: clamp(2.5rem, 6vw, 5rem);
}

.section-head {
  display: flex;
  flex-direction: column;
  gap: .35rem;
  margin-bottom: 1.5rem;
}

.section-label {
  display: inline-flex;
  align-items: center;
  gap: .6rem;
  align-self: flex-start;
  background: var(--arena-deep);
  color: var(--arena-gold);
  font-weight: 900;
  font-size: .72rem;
  letter-spacing: .16em;
  text-transform: uppercase;
  padding: .4rem .8rem;
}

.section-label::before {
  content: "";
  width: 1.6rem;
  height: 2px;
  background: var(--arena-gold);
}

.section-title {
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(1.5rem, 3.2vw, 2.5rem);
  line-height: 1.15;
  color: var(--arena-charcoal);
}

.section-note {
  color: var(--arena-slate);
  max-width: 70ch;
  margin-top: .3rem;
}

.lead {
  font-size: 1.125rem;
  line-height: 1.7;
  color: var(--arena-slate);
  max-width: 75ch;
}

.grid-12 {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  gap: var(--gutter);
}

.grid-main {
  grid-column: span 8;
  min-width: 0;
}

.grid-side {
  grid-column: span 4;
  min-width: 0;
}

.paper-stack {
  position: relative;
  background: var(--arena-paper);
  border: 1px solid var(--arena-moss);
  box-shadow: 5px 5px 0 var(--arena-ivory), 10px 10px 0 rgba(11, 61, 46, .06);
  padding: clamp(1.25rem, 3vw, 2rem);
}

.paper-stack[data-label]::before {
  content: attr(data-label);
  position: absolute;
  top: -1.1rem;
  left: 1rem;
  background: var(--arena-gold);
  color: var(--arena-charcoal);
  font-size: .72rem;
  font-weight: 900;
  letter-spacing: .12em;
  text-transform: uppercase;
  padding: .3rem .75rem;
}

.visual-frame {
  position: relative;
  overflow: hidden;
  background: linear-gradient(135deg, var(--arena-ivory) 0%, var(--arena-fern) 120%);
  border: 1px solid var(--arena-moss);
}

.visual-frame::before {
  content: "";
  display: block;
  padding-bottom: 56.25%;
}

.visual-frame[data-ratio="4/3"]::before {
  padding-bottom: 75%;
}

.visual-frame[data-ratio="3/2"]::before {
  padding-bottom: 66.66%;
}

.visual-frame[data-ratio="1/1"]::before {
  padding-bottom: 100%;
}

.visual-frame img {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: .5rem;
  padding: .72rem 1.25rem;
  background: var(--arena-deep);
  color: var(--arena-paper);
  border: 1px solid var(--arena-deep);
  border-radius: 0;
  font-weight: 800;
  font-size: .9rem;
  letter-spacing: .05em;
  text-decoration: none;
  cursor: pointer;
  transition: background .2s, border-color .2s, color .2s;
}

.btn::after {
  content: "→";
  display: inline-block;
  transition: transform .2s;
}

.btn:hover,
.btn:focus-visible {
  background: var(--arena-pine);
  border-color: var(--arena-pine);
}

.btn:hover::after,
.btn:focus-visible::after {
  transform: translateX(4px);
}

.btn--ghost {
  background: transparent;
  color: var(--arena-deep);
  border-color: var(--arena-deep);
}

.btn--ghost:hover {
  background: var(--arena-deep);
  color: var(--arena-paper);
}

.btn--gold {
  background: var(--arena-gold);
  color: var(--arena-charcoal);
  border-color: var(--arena-gold);
}

.btn--gold:hover {
  background: var(--arena-gold-soft);
  border-color: var(--arena-gold-soft);
  color: var(--arena-charcoal);
}

.archive-tab {
  display: inline-flex;
  align-items: center;
  gap: .6rem;
  background: var(--arena-ivory);
  border: 1px solid var(--arena-moss);
  border-top: 3px solid var(--arena-gold);
  color: var(--arena-deep);
  font-size: .78rem;
  font-weight: 900;
  letter-spacing: .14em;
  text-transform: uppercase;
  padding: .6rem 1rem;
}

.archive-tab::before {
  content: "";
  width: 7px;
  height: 7px;
  background: var(--arena-gold);
  border-radius: 50%;
}

.tag-list {
  display: flex;
  flex-wrap: wrap;
  gap: .5rem;
}

.tag-label {
  display: inline-flex;
  align-items: center;
  background: var(--arena-ivory);
  border: 1px solid var(--arena-moss);
  color: var(--arena-deep);
  font-size: .75rem;
  font-weight: 800;
  letter-spacing: .06em;
  padding: .3rem .7rem;
}

.tag-label[data-tone="gold"] {
  background: var(--arena-gold);
  border-color: var(--arena-gold);
  color: var(--arena-charcoal);
}

.data-table {
  width: 100%;
  border-collapse: collapse;
  background: var(--arena-paper);
  border: 1px solid var(--arena-moss);
  font-variant-numeric: tabular-nums;
}

.data-table th,
.data-table td {
  padding: .75rem 1rem;
  border-bottom: 1px solid var(--arena-ivory);
  text-align: left;
  vertical-align: top;
}

.data-table th {
  background: var(--arena-deep);
  color: var(--arena-gold);
  font-family: var(--font-display);
  font-weight: 900;
  font-size: .76rem;
  letter-spacing: .14em;
  text-transform: uppercase;
}

.data-table tbody tr:hover {
  background: var(--arena-ivory);
}

.data-table td[data-num],
.data-table td.num {
  font-family: var(--font-data);
  text-align: right;
}

.breadcrumbs {
  display: flex;
  flex-wrap: wrap;
  gap: .5rem;
  margin-bottom: 1.5rem;
  font-size: .85rem;
}

.breadcrumbs li {
  display: flex;
  align-items: center;
  gap: .5rem;
}

.breadcrumbs li + li::before {
  content: "/";
  color: var(--arena-moss);
  font-weight: 700;
}

.breadcrumbs a {
  color: var(--arena-deep);
  font-weight: 700;
  text-decoration: none;
}

.breadcrumbs a:hover {
  color: var(--arena-pine);
}

.breadcrumbs [aria-current="page"] {
  color: var(--arena-slate);
  font-weight: 600;
}

.prose {
  max-width: 72ch;
}

.prose > * + * {
  margin-top: 1rem;
}

.caption {
  font-size: .78rem;
  color: var(--arena-slate);
  letter-spacing: .05em;
}

.card {
  display: flex;
  flex-direction: column;
  background: var(--arena-paper);
  border: 1px solid var(--arena-moss);
  box-shadow: 4px 4px 0 var(--arena-ivory);
  text-decoration: none;
  color: inherit;
  transition: box-shadow .2s, transform .2s;
}

.card:hover {
  transform: translateY(-2px);
  box-shadow: 6px 6px 0 rgba(11, 61, 46, .1);
}

.card-media .visual-frame {
  border: none;
  border-bottom: 1px solid var(--arena-moss);
}

.card-body {
  padding: 1rem;
}

.card-title {
  font-family: var(--font-display);
  font-weight: 900;
  font-size: 1.25rem;
  line-height: 1.25;
  color: var(--arena-charcoal);
}

.card-meta {
  margin-top: .5rem;
  font-family: var(--font-data);
  font-size: .8rem;
  color: var(--arena-slate);
}

.card-link {
  display: inline-flex;
  align-items: center;
  gap: .4rem;
  margin-top: .8rem;
  font-weight: 800;
  color: var(--arena-deep);
  text-decoration: none;
}

.card-link::after {
  content: "→";
  display: inline-block;
  transition: transform .2s;
}

.card:hover .card-link::after,
.card-link:hover::after {
  transform: translateX(4px);
}

@media (max-width: 900px) {
  .grid-main,
  .grid-side {
    grid-column: 1 / -1;
  }

  .footer-shell {
    grid-template-columns: 1fr 1fr;
  }

  .site-nav-list {
    justify-content: flex-start;
    overflow-x: auto;
  }
}

@media (max-width: 760px) {
  .masthead {
    text-align: left;
    padding-right: calc(var(--gutter) + 3.2rem);
  }

  .masthead::before,
  .masthead::after {
    display: none;
  }

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

  .nav-toggle {
    display: inline-flex;
    align-items: center;
    gap: .55rem;
    position: absolute;
    right: var(--gutter);
    bottom: .85rem;
    border: 1px solid rgba(212, 175, 55, .45);
    color: var(--arena-gold);
    padding: .45rem .75rem;
    background: transparent;
    font-weight: 800;
    font-size: .78rem;
    letter-spacing: .12em;
  }

  .nav-toggle:hover {
    border-color: var(--arena-gold);
    color: var(--arena-gold-soft);
  }

  .nav-toggle-label {
    font-size: .78rem;
    letter-spacing: .12em;
  }

  .nav-toggle-box {
    width: 18px;
    height: 14px;
    position: relative;
  }

  .nav-toggle-box span,
  .nav-toggle-box span::before,
  .nav-toggle-box span::after {
    content: "";
    position: absolute;
    left: 0;
    width: 100%;
    height: 2px;
    background: currentColor;
  }

  .nav-toggle-box span {
    top: 6px;
  }

  .nav-toggle-box span::before {
    top: -5px;
  }

  .nav-toggle-box span::after {
    top: 5px;
  }

  .site-nav {
    display: none;
    padding: 0;
    border-top: 1px solid rgba(212, 175, 55, .4);
  }

  .site-nav[data-open] {
    display: block;
  }

  .site-nav-list {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: .35rem var(--gutter) .5rem;
  }

  .nav-link {
    padding: .9rem 0;
    border-bottom: 1px solid rgba(244, 241, 232, .12);
  }

  .nav-link[aria-current="page"] {
    border-bottom-color: var(--arena-gold);
  }

  .footer-shell {
    grid-template-columns: 1fr;
  }

  .footer-trust {
    flex-direction: column;
  }

  .footer-bottom {
    flex-direction: column;
  }
}

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

  *,
  *::before,
  *::after {
    animation-duration: .001ms !important;
    transition-duration: .001ms !important;
  }

  .btn::after,
  .card-link::after {
    transform: none !important;
  }
}