:root {
      --bg:      #1c1f24;
      --bg2:     #23272e;
      --bg3:     #2a2f38;
      --bg4:     #313740;
      --border:  #3a4050;
      --border2: #454d5c;
      --steel:   #8a9ab0;
      --steel2:  #6a7a90;
      --steel3:  #4a5a6a;
      --orange:  #e87820;
      --orange2: #f09040;
      --white:   #eef0f4;
      --text:    #c8d0dc;
      --dim:     #5a6478;
    }

    *, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
    html { scroll-behavior: smooth; }

    body {
      background: var(--bg);
      color: var(--text);
      font-family: 'Source Serif 4', Georgia, serif;
      font-weight: 300;
      font-size: 16px;
      line-height: 1.7;
      overflow-x: hidden;
    }

    /* ── GRID BACKGROUND ── */
    body::before {
      content: '';
      position: fixed;
      inset: 0;
      background-image:
        linear-gradient(rgba(58,64,80,0.3) 1px, transparent 1px),
        linear-gradient(90deg, rgba(58,64,80,0.3) 1px, transparent 1px);
      background-size: 40px 40px;
      pointer-events: none;
      z-index: 0;
    }

    /* ── HEADER ── */
    header {
      position: relative;
      z-index: 10;
      background: var(--bg2);
      border-bottom: 2px solid var(--orange);
    }

    .header-inner {
      max-width: 1100px;
      margin: 0 auto;
      padding: 0 2rem;
      height: 60px;
      display: flex;
      align-items: center;
      justify-content: space-between;
    }

    .logo {
      display: flex;
      align-items: baseline;
      gap: 0.8rem;
      text-decoration: none;
    }

    .logo-main {
      font-family: 'Rajdhani', sans-serif;
      font-size: 1.4rem;
      font-weight: 700;
      letter-spacing: 0.12em;
      text-transform: uppercase;
      color: var(--white);
    }

    .logo-main span { color: var(--orange); }

    .logo-sub {
      font-family: 'Roboto Mono', monospace;
      font-size: 0.58rem;
      color: var(--steel3);
      letter-spacing: 0.1em;
      text-transform: uppercase;
    }

    .header-nav {
      display: flex;
      list-style: none;
      gap: 0;
    }

    .header-nav a {
      font-family: 'Rajdhani', sans-serif;
      font-size: 0.82rem;
      font-weight: 600;
      letter-spacing: 0.1em;
      text-transform: uppercase;
      color: var(--steel2);
      text-decoration: none;
      padding: 0 1.2rem;
      height: 60px;
      display: flex;
      align-items: center;
      border-left: 1px solid var(--border);
      transition: color 0.15s, background 0.15s;
    }

    .header-nav a:hover,
    .header-nav a.active {
      color: var(--orange);
      background: var(--bg3);
    }

    /* ── HERO ── */
    .hero {
      position: relative;
      z-index: 1;
      max-width: 1100px;
      margin: 0 auto;
      padding: 5rem 2rem 4rem;
      display: grid;
      grid-template-columns: 1fr 360px;
      gap: 3rem;
      align-items: center;
    }

    .hero-left {}

    .hero-badge {
      font-family: 'Roboto Mono', monospace;
      font-size: 0.65rem;
      font-weight: 500;
      letter-spacing: 0.18em;
      text-transform: uppercase;
      color: var(--orange);
      background: rgba(232,120,32,0.1);
      border: 1px solid rgba(232,120,32,0.3);
      padding: 0.3rem 0.8rem;
      display: inline-block;
      margin-bottom: 1.8rem;
    }

    h1 {
      font-family: 'Rajdhani', sans-serif;
      font-size: clamp(2rem, 4vw, 3.2rem);
      font-weight: 700;
      line-height: 1.1;
      text-transform: uppercase;
      letter-spacing: 0.04em;
      color: var(--white);
      margin-bottom: 1.5rem;
    }

    h1 em {
      font-style: normal;
      color: var(--orange);
    }

    .hero-intro {
      font-size: 0.97rem;
      color: var(--text);
      line-height: 1.8;
      max-width: 560px;
      margin-bottom: 2rem;
    }

    .hero-intro a {
      color: var(--orange2);
      text-decoration: none;
      border-bottom: 1px solid rgba(232,120,32,0.35);
      transition: border-color 0.2s;
    }

    .hero-intro a:hover { border-color: var(--orange2); }

    /* ── SIGNAL PANEL ── */
    .signal-panel {
      background: var(--bg2);
      border: 1px solid var(--border);
      border-top: 3px solid var(--orange);
    }

    .signal-header {
      font-family: 'Roboto Mono', monospace;
      font-size: 0.6rem;
      font-weight: 500;
      letter-spacing: 0.15em;
      text-transform: uppercase;
      color: var(--orange);
      padding: 0.7rem 1.2rem;
      border-bottom: 1px solid var(--border);
      background: var(--bg3);
    }

    .signal-row {
      display: flex;
      justify-content: space-between;
      align-items: center;
      padding: 0.9rem 1.2rem;
      border-bottom: 1px solid var(--border);
      transition: background 0.15s;
    }

    .signal-row:last-child { border-bottom: none; }
    .signal-row:hover { background: var(--bg3); }

    .signal-label {
      font-family: 'Roboto Mono', monospace;
      font-size: 0.7rem;
      color: var(--steel);
      letter-spacing: 0.05em;
    }

    .signal-val {
      font-family: 'Roboto Mono', monospace;
      font-size: 0.7rem;
      font-weight: 500;
    }

    .signal-val.ok     { color: #5ab870; }
    .signal-val.warn   { color: var(--orange2); }
    .signal-val.alert  { color: #e05050; }
    .signal-val.info   { color: var(--steel); }

    .signal-dot {
      display: inline-block;
      width: 6px; height: 6px;
      border-radius: 50%;
      margin-right: 0.5rem;
      vertical-align: middle;
    }

    .dot-ok    { background: #5ab870; }
    .dot-warn  { background: var(--orange2); }
    .dot-alert { background: #e05050; }

    /* ── DIVIDER ── */
    .divider {
      position: relative;
      z-index: 1;
      border: none;
      border-top: 1px solid var(--border);
      max-width: 1100px;
      margin: 0 auto;
    }

    /* ── SECTION ── */
    .section {
      position: relative;
      z-index: 1;
      max-width: 1100px;
      margin: 0 auto;
      padding: 4rem 2rem;
    }

    .section-head {
      display: flex;
      align-items: center;
      gap: 1rem;
      margin-bottom: 2.5rem;
      padding-bottom: 0.8rem;
      border-bottom: 1px solid var(--border);
    }

    .section-tag {
      font-family: 'Roboto Mono', monospace;
      font-size: 0.6rem;
      font-weight: 500;
      letter-spacing: 0.15em;
      text-transform: uppercase;
      background: var(--orange);
      color: #fff;
      padding: 0.2rem 0.6rem;
      flex-shrink: 0;
    }

    .section h2 {
      font-family: 'Rajdhani', sans-serif;
      font-size: 1.4rem;
      font-weight: 700;
      text-transform: uppercase;
      letter-spacing: 0.06em;
      color: var(--white);
    }

    /* ── SPLIT ── */
    .split {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 1px;
      background: var(--border);
      border: 1px solid var(--border);
      margin-bottom: 2.5rem;
    }

    .split-col {
      background: var(--bg2);
      padding: 2rem;
      transition: background 0.2s;
    }

    .split-col:hover { background: var(--bg3); }

    .split-col-tag {
      font-family: 'Roboto Mono', monospace;
      font-size: 0.6rem;
      letter-spacing: 0.14em;
      text-transform: uppercase;
      margin-bottom: 0.8rem;
      padding-bottom: 0.6rem;
      border-bottom: 2px solid;
    }

    .split-col-tag.era-radio { color: var(--steel2); border-color: var(--steel3); }
    .split-col-tag.era-ip    { color: var(--orange); border-color: var(--orange); }

    .split-col h3 {
      font-family: 'Rajdhani', sans-serif;
      font-size: 1.05rem;
      font-weight: 700;
      text-transform: uppercase;
      letter-spacing: 0.04em;
      color: var(--white);
      margin-bottom: 0.8rem;
    }

    .split-col p {
      font-size: 0.9rem;
      color: var(--text);
      line-height: 1.7;
      margin-bottom: 0.7rem;
    }

    /* ── PROSE ── */
    .prose p {
      font-size: 0.95rem;
      color: var(--text);
      line-height: 1.82;
      margin-bottom: 1.2rem;
      max-width: 720px;
    }

    .prose strong { color: var(--white); font-weight: 400; }

    /* ── SPEC TABLE ── */
    .spec-table {
      width: 100%;
      border-collapse: collapse;
      border: 1px solid var(--border);
      font-size: 0.875rem;
      margin-top: 2rem;
    }

    .spec-table thead { background: var(--bg3); }

    .spec-table th {
      font-family: 'Roboto Mono', monospace;
      font-size: 0.6rem;
      font-weight: 500;
      letter-spacing: 0.12em;
      text-transform: uppercase;
      color: var(--orange);
      padding: 0.8rem 1.2rem;
      text-align: left;
      border-bottom: 1px solid var(--border);
    }

    .spec-table td {
      padding: 0.8rem 1.2rem;
      border-bottom: 1px solid var(--border);
      color: var(--text);
      vertical-align: top;
    }

    .spec-table tr:last-child td { border-bottom: none; }
    .spec-table tr:hover td { background: var(--bg3); }

    .td-good { color: #5ab870; font-family: 'Roboto Mono', monospace; font-size: 0.75rem; }
    .td-warn { color: var(--orange2); font-family: 'Roboto Mono', monospace; font-size: 0.75rem; }
    .td-neutral { color: var(--steel); font-family: 'Roboto Mono', monospace; font-size: 0.75rem; }

    code {
      font-family: 'Roboto Mono', monospace;
      font-size: 0.8em;
      background: var(--bg4);
      border: 1px solid var(--border);
      padding: 0.1em 0.4em;
      color: var(--orange2);
    }

    /* ── CALLOUT ── */
    .callout {
      background: var(--bg2);
      border: 1px solid var(--border);
      border-left: 3px solid var(--orange);
      padding: 1.3rem 1.8rem;
      margin: 2rem 0;
    }

    .callout-label {
      font-family: 'Roboto Mono', monospace;
      font-size: 0.6rem;
      font-weight: 500;
      letter-spacing: 0.14em;
      text-transform: uppercase;
      color: var(--orange);
      margin-bottom: 0.5rem;
    }

    .callout p {
      font-size: 0.88rem;
      color: var(--steel);
      line-height: 1.65;
    }

    /* ── FOOTER ── */
    footer {
      position: relative;
      z-index: 1;
      border-top: 2px solid var(--orange);
      background: var(--bg2);
      padding: 2rem;
      display: flex;
      justify-content: space-between;
      align-items: center;
      max-width: 100%;
    }

    .footer-inner {
      max-width: 1100px;
      margin: 0 auto;
      width: 100%;
      display: flex;
      justify-content: space-between;
      align-items: center;
      flex-wrap: wrap;
      gap: 1rem;
    }

    .footer-logo {
      font-family: 'Rajdhani', sans-serif;
      font-size: 0.9rem;
      font-weight: 700;
      letter-spacing: 0.12em;
      text-transform: uppercase;
      color: var(--steel2);
    }

    .footer-logo span { color: var(--orange); }

    .footer-copy {
      font-family: 'Roboto Mono', monospace;
      font-size: 0.62rem;
      color: var(--dim);
      letter-spacing: 0.08em;
    }

    /* ── ANIMATIONS ── */
    @keyframes fadeIn {
      from { opacity: 0; transform: translateY(12px); }
      to   { opacity: 1; transform: translateY(0); }
    }

    .hero > * {
      animation: fadeIn 0.45s ease both;
    }

    .hero-left { animation-delay: 0.05s; }
    .hero-right { animation-delay: 0.18s; }

    /* ── RESPONSIVE ── */
    
    /* ── HAMBURGER & MOBILE MENU ── */
    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      cursor: pointer;
      padding: 4px;
      background: none;
      border: none;
      z-index: 200;
    }

    .hamburger span {
      display: block;
      width: 22px;
      height: 2px;
      background: #fff;
      transition: transform 0.25s, opacity 0.25s;
      transform-origin: center;
    }

    .hamburger.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
    .hamburger.open span:nth-child(2) { opacity: 0; }
    .hamburger.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

    .mobile-menu {
      display: none;
      position: fixed;
      top: 60px;
      left: 0; right: 0; bottom: 0;
      background: var(--bg2);
      z-index: 99;
      overflow-y: auto;
      padding: 1.5rem 2rem;
      flex-direction: column;
      border-top: 2px solid var(--orange);
    }

    .mobile-menu.open { display: flex; }

    .mobile-menu a {
      font-family: 'Rajdhani', sans-serif;
      font-size: 1.1rem;
      font-weight: 700;
      text-transform: uppercase;
      letter-spacing: 0.06em;
      color: var(--steel2);
      text-decoration: none;
      padding: 1rem 0;
      border-bottom: 1px solid var(--border);
      transition: color 0.15s;
    }

    .mobile-menu a:hover,
    .mobile-menu a.active { color: var(--orange); }

@media (max-width: 860px) {
      .hero { grid-template-columns: 1fr; }
      .split { grid-template-columns: 1fr; }
      .spec-table { font-size: 0.78rem; }
      .header-nav { display: none; }
      .hamburger  { display: flex; }
    }
  
    /* ── BREADCRUMB ── */
    .breadcrumb {
      position: relative;
      z-index: 1;
      max-width: 1100px;
      margin: 0 auto;
      padding: 1rem 2rem 0;
      font-family: 'Roboto Mono', monospace;
      font-size: 0.62rem;
      color: var(--steel3);
      letter-spacing: 0.08em;
      text-transform: uppercase;
      display: flex;
      gap: 0.6rem;
      align-items: center;
    }

    .breadcrumb a { color: var(--steel3); text-decoration: none; transition: color 0.15s; }
    .breadcrumb a:hover { color: var(--orange); }

    /* ── PAGE HERO ── */
    .page-hero {
      position: relative;
      z-index: 1;
      max-width: 1100px;
      margin: 0 auto;
      padding: 3.5rem 2rem 3rem;
      border-bottom: 1px solid var(--border);
    }

    .page-tag {
      font-family: 'Roboto Mono', monospace;
      font-size: 0.6rem;
      font-weight: 500;
      letter-spacing: 0.15em;
      text-transform: uppercase;
      background: var(--orange);
      color: #fff;
      padding: 0.25rem 0.7rem;
      display: inline-block;
      margin-bottom: 1.2rem;
    }

    .page-hero h1 {
      font-family: 'Rajdhani', sans-serif;
      font-size: clamp(1.8rem, 3.5vw, 2.8rem);
      font-weight: 700;
      text-transform: uppercase;
      letter-spacing: 0.04em;
      line-height: 1.1;
      color: var(--white);
      margin-bottom: 1.2rem;
    }

    .page-hero h1 em { font-style: normal; color: var(--orange); }

    .page-intro {
      font-size: 0.97rem;
      color: var(--text);
      line-height: 1.8;
      max-width: 680px;
    }

    /* ── ARTICLE BODY ── */
    .article-body {
      position: relative;
      z-index: 1;
      max-width: 1100px;
      margin: 0 auto;
      padding: 3rem 2rem 5rem;
    }

    .article-body h2 {
      font-family: 'Rajdhani', sans-serif;
      font-size: 1.3rem;
      font-weight: 700;
      text-transform: uppercase;
      letter-spacing: 0.06em;
      color: var(--white);
      margin: 3rem 0 1rem;
      padding-bottom: 0.6rem;
      border-bottom: 1px solid var(--border);
    }

    .article-body h2:first-child { margin-top: 0; }

    .article-body h3 {
      font-family: 'Roboto Mono', monospace;
      font-size: 0.78rem;
      font-weight: 500;
      letter-spacing: 0.1em;
      text-transform: uppercase;
      color: var(--orange2);
      margin: 2rem 0 0.6rem;
    }

    .article-body p {
      font-size: 0.95rem;
      color: var(--text);
      line-height: 1.82;
      margin-bottom: 1.2rem;
      max-width: 720px;
    }

    .article-body p:last-child { margin-bottom: 0; }
    .article-body strong { color: var(--white); font-weight: 400; }

    .article-body a {
      color: var(--orange2);
      text-decoration: none;
      border-bottom: 1px solid rgba(240,144,64,0.35);
      transition: border-color 0.2s;
    }

    .article-body a:hover { border-color: var(--orange2); }

    /* ── DIAGRAM WRAP ── */
    .diagram-wrap {
      margin: 2rem 0;
      border: 1px solid var(--border);
      background: var(--bg2);
      overflow-x: auto;
    }

    .diagram-wrap svg { display: block; width: 100%; }