:root {
      color-scheme: dark;
      --bg: #060a11;
      --panel: #0d1826;
      --ink: #d4e6f5;
      --muted: #7e96ad;
      --line: #1f3145;
      --brand: #2bd4a6;
      --blue: #38bdf8;
      --red: #f8736e;
      --shadow: 0 22px 58px rgba(22, 32, 51, .13);
    }
    * { box-sizing: border-box; }
    body {
      margin: 0;
      min-height: 100vh;
      font-family: "Segoe UI", Arial, sans-serif;
      background:
        linear-gradient(135deg, rgba(15,118,110,.10), transparent 34%),
        linear-gradient(315deg, rgba(29,78,216,.10), transparent 38%),
        var(--bg);
      color: var(--ink);
      display: grid;
      place-items: center;
      padding: 22px;
    }
    .login-shell {
      width: min(960px, 100%);
      display: grid;
      grid-template-columns: minmax(0, .9fr) minmax(340px, 420px);
      gap: 20px;
      align-items: stretch;
    }
    .intro, .panel {
      background: rgba(13,24,38,.92);
      border: 1px solid var(--line);
      border-radius: 8px;
      box-shadow: var(--shadow);
    }
    .intro {
      padding: 26px;
      display: flex;
      flex-direction: column;
      justify-content: space-between;
      min-height: 500px;
    }
    .eyebrow {
      color: var(--brand);
      font-weight: 700;
      font-size: 12px;
      text-transform: uppercase;
      letter-spacing: .08em;
    }
    h1 {
      margin: 14px 0 10px;
      font-size: 38px;
      line-height: 1.05;
      letter-spacing: 0;
    }
    p { margin: 0; color: var(--muted); line-height: 1.55; }
    .principles {
      display: grid;
      gap: 10px;
      margin-top: 22px;
    }
    .principle {
      display: flex;
      gap: 10px;
      align-items: flex-start;
      padding: 11px;
      border: 1px solid var(--line);
      border-radius: 8px;
      background: #122132;
      font-size: 13px;
    }
    .mark {
      width: 22px;
      height: 22px;
      border-radius: 50%;
      display: grid;
      place-items: center;
      background: rgba(43,212,166,0.10);
      color: var(--brand);
      font-weight: 800;
      flex: 0 0 auto;
    }
    .panel { padding: 22px; }
    .panel h2 { margin: 0 0 4px; font-size: 21px; }
    .panel .sub { margin-bottom: 20px; font-size: 13px; }
    label {
      display: block;
      margin: 13px 0 6px;
      color: var(--muted);
      font-size: 12px;
      font-weight: 600;
    }
    input, select {
      width: 100%;
      min-height: 42px;
      border: 1px solid var(--line);
      border-radius: 7px;
      padding: 10px 11px;
      font: inherit;
      color: var(--ink);
      background: var(--panel);
    }
    .row {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 10px;
    }
    .field-group {
      display: grid;
      gap: 0;
    }
    .hidden { display: none; }
    button {
      width: 100%;
      min-height: 42px;
      margin-top: 18px;
      border: 1px solid var(--brand);
      border-radius: 7px;
      background: var(--brand);
      color: #fff;
      font: inherit;
      font-weight: 700;
      cursor: pointer;
    }
    button:hover { background: #2bd4a6; }
    .error {
      display: none;
      margin-top: 12px;
      padding: 10px;
      border: 1px solid rgba(248,115,110,0.45);
      border-radius: 7px;
      color: var(--red);
      background: rgba(248,115,110,0.12);
      font-size: 13px;
    }
    .hint {
      margin-top: 12px;
      color: var(--muted);
      font-size: 12px;
      line-height: 1.45;
    }
    .role-help {
      margin-top: 8px;
      padding: 10px 11px;
      border: 1px solid var(--line);
      border-radius: 7px;
      background: #122132;
      color: var(--muted);
      font-size: 12px;
      line-height: 1.45;
    }
    @media (max-width: 820px) {
      body { place-items: stretch; }
      .login-shell { grid-template-columns: 1fr; }
      .intro { min-height: auto; }
      h1 { font-size: 30px; }
      .row { grid-template-columns: 1fr; }
    }

    /* ===================== CYBER RANGE polish ===================== */
    body {
      background:
        radial-gradient(1000px 560px at 84% -12%, rgba(43,212,166,.14), transparent 60%),
        radial-gradient(820px 560px at -8% 112%, rgba(56,189,248,.14), transparent 60%),
        linear-gradient(rgba(31,49,69,.18) 1px, transparent 1px) 0 0 / 100% 30px,
        linear-gradient(90deg, rgba(31,49,69,.18) 1px, transparent 1px) 0 0 / 30px 100%,
        var(--bg);
    }
    .cr-brand { display:inline-flex; align-items:center; gap:10px; font-family: ui-monospace,'JetBrains Mono',monospace; font-weight:800; letter-spacing:4px; font-size:15px; color:var(--brand); text-shadow:0 0 16px rgba(43,212,166,.6); text-transform:uppercase; margin-bottom:14px; }
    .cr-brand .dot { width:11px; height:11px; border-radius:2px; background:var(--brand); box-shadow:0 0 12px var(--brand); transform:rotate(45deg); }
    h1 { letter-spacing:.3px; }
    .intro, .panel { box-shadow: var(--shadow), 0 0 0 1px rgba(43,212,166,.06); }
    input:focus, select:focus { outline:none; border-color: var(--brand); box-shadow:0 0 0 2px rgba(43,212,166,.20); }
    ::selection { background: rgba(43,212,166,.35); color:#eafff7; }