* { box-sizing: border-box; }
  html, body {
    margin: 0;
    padding: 0;
    height: 100%;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  }
  body {
    background: radial-gradient(ellipse at center, #04231e 0%, #020f0d 75%);
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
    position: relative;
    overflow: hidden;
  }
  #brain-canvas { pointer-events: auto; }
  .card {
    position: relative;
    z-index: 1;
    width: 100%;
    max-width: 380px;
    background: rgba(6, 38, 33, 0.55);
    backdrop-filter: blur(14px);
    -webkit-backdrop-filter: blur(14px);
    border: 1px solid rgba(45, 212, 191, 0.18);
    border-radius: 20px;
    box-shadow: 0 25px 60px -12px rgba(0, 0, 0, 0.55), 0 0 40px -10px rgba(45, 212, 191, 0.1);
    padding: 40px;
    transition: transform 80ms ease-out;
    pointer-events: auto;
  }
  .card.shake { animation: card-shake 300ms ease-in-out; }
  @keyframes card-shake {
    0%, 100% { transform: translateX(0); }
    20% { transform: translateX(-6px); }
    40% { transform: translateX(6px); }
    60% { transform: translateX(-4px); }
    80% { transform: translateX(4px); }
  }
  .logo {
    width: 56px;
    height: 56px;
    border-radius: 12px;
    margin: 0 auto 20px;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
    background: #075E54;
    box-shadow: 0 0 24px 2px rgba(45, 212, 191, 0.35);
  }
  .logo img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: block;
  }
  .logo-fallback {
    color: #FFFFFF;
    font-weight: 800;
    font-size: 26px;
  }
  h1 {
    margin: 0 0 4px;
    text-align: center;
    font-size: 26px;
    font-weight: 700;
    color: #FFFFFF;
  }
  .subtitle {
    margin: 0 0 28px;
    text-align: center;
    font-size: 14px;
    color: rgba(255, 255, 255, 0.55);
  }
  label {
    display: block;
    font-size: 10px;
    font-weight: 800;
    letter-spacing: 1.2px;
    text-transform: uppercase;
    color: rgba(127, 255, 212, 0.7);
    margin-bottom: 8px;
  }
  .field-wrap {
    position: relative;
    margin-bottom: 8px;
  }
  .field-icon {
    position: absolute;
    left: 14px;
    top: 50%;
    transform: translateY(-50%);
    color: rgba(255, 255, 255, 0.5);
    display: flex;
    pointer-events: none;
  }
  input[type="password"],
  input[type="text"] {
    width: 100%;
    height: 46px;
    border-radius: 12px;
    border: 1.5px solid rgba(45, 212, 191, 0.25);
    background: rgba(255, 255, 255, 0.06);
    padding: 0 44px 0 40px;
    font-size: 15px;
    color: #FFFFFF;
    outline: none;
    transition: border-color 150ms, box-shadow 150ms, background 150ms;
  }
  input[type="password"]::placeholder,
  input[type="text"]::placeholder {
    color: rgba(255, 255, 255, 0.35);
  }
  input[type="password"]:focus,
  input[type="text"]:focus {
    border-color: #2DD4BF;
    box-shadow: 0 0 0 3px rgba(45, 212, 191, 0.15);
    background: rgba(255, 255, 255, 0.09);
  }
  .toggle-visibility {
    position: absolute;
    right: 10px;
    top: 50%;
    transform: translateY(-50%);
    background: none;
    border: none;
    padding: 6px;
    cursor: pointer;
    color: rgba(255, 255, 255, 0.5);
    display: flex;
    border-radius: 6px;
  }
  .toggle-visibility:hover {
    color: rgba(255, 255, 255, 0.8);
    background: rgba(255, 255, 255, 0.08);
  }
  .error-banner {
    display: none;
    align-items: center;
    gap: 8px;
    margin: 16px 0 0;
    padding: 10px 12px;
    border-radius: 10px;
    background: rgba(248, 113, 113, 0.12);
    border: 1px solid rgba(248, 113, 113, 0.35);
    color: #fca5a5;
    font-size: 13px;
  }
  .error-banner.visible { display: flex; }
  button[type="submit"] {
    width: 100%;
    height: 48px;
    margin-top: 20px;
    border: none;
    border-radius: 12px;
    background: linear-gradient(135deg, #0d9488, #2DD4BF);
    color: #04231e;
    font-size: 15px;
    font-weight: 700;
    cursor: pointer;
    transition: filter 150ms, box-shadow 150ms, transform 150ms;
  }
  button[type="submit"]:hover:not(:disabled) {
    filter: brightness(1.1);
    box-shadow: 0 8px 24px rgba(45, 212, 191, 0.35);
  }
  button[type="submit"]:active:not(:disabled) { transform: scale(0.98); }
  button[type="submit"]:disabled { opacity: 0.7; cursor: default; }
  .footer {
    margin-top: 24px;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    color: rgba(255, 255, 255, 0.35);
    font-size: 12px;
  }
  @media (max-width: 480px) {
    .card { margin: 16px; padding: 32px 24px; }
  }