<style>
  /* ==========================================
     ESTILOS - LOGIN GLYMTEC
     ========================================== */
  :root {
    --bg-dark: #000000;
    --neon-blue: #00f3ff;
    --glass-bg: rgba(255, 255, 255, 0.05);
    --glass-border: rgba(0, 243, 255, 0.2);
    --text-white: #ffffff;
  }

  body {
    margin: 0;
    padding: 0;
    background-color: var(--bg-dark);
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    color: var(--text-white);
    
    /* ESTO ES LO QUE CENTRA */
    display: flex;
    justify-content: center; /* Centrado horizontal */
    align-items: center;     /* Centrado vertical */
    
    min-height: 100vh;       /* Que use el 100% del alto de la pantalla */
    width: 100vw;            /* Que use el 100% del ancho */
    overflow: hidden;
  }

  #login-container {
    width: 90%;              /* En móviles ocupa casi todo el ancho */
    max-width: 350px;        /* En PC no se estira más de esto */
    background: var(--glass-bg);
    padding: 40px 30px;
    border-radius: 15px;
    border: 1px solid var(--glass-border);
    backdrop-filter: blur(10px);
    box-shadow: 0 0 20px rgba(0, 243, 255, 0.1);
    text-align: center;
  }

  .logo-glow {
    font-size: 28px;
    font-weight: bold;
    color: var(--text-white);
    text-shadow: 0 0 10px var(--neon-blue), 0 0 20px var(--neon-blue);
    margin-bottom: 30px;
    letter-spacing: 2px;
  }

  .input-group {
    position: relative;
    margin-bottom: 20px;
    text-align: left;
  }

  .input-glass {
    width: 100%;
    padding: 12px 15px;
    background: rgba(0, 0, 0, 0.5);
    border: 1px solid var(--glass-border);
    border-radius: 8px;
    color: var(--text-white);
    font-size: 16px;
    box-sizing: border-box;
    outline: none;
    transition: all 0.3s ease;
  }

  .input-glass:focus {
    border-color: var(--neon-blue);
    box-shadow: 0 0 10px rgba(0, 243, 255, 0.3);
  }

  .toggle-password {
    position: absolute;
    right: 15px;
    top: 50%;
    transform: translateY(-50%);
    cursor: pointer;
    fill: var(--neon-blue);
    width: 20px;
    height: 20px;
  }

  .btn-neon {
    width: 100%;
    padding: 12px;
    background-color: var(--neon-blue);
    color: var(--text-white);
    border: none;
    border-radius: 8px;
    font-size: 16px;
    font-weight: bold;
    cursor: pointer;
    box-shadow: 0 0 15px rgba(0, 243, 255, 0.5);
    transition: all 0.3s ease;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 45px;
  }

  .btn-neon:hover {
    box-shadow: 0 0 25px rgba(0, 243, 255, 0.8);
    transform: scale(1.02);
  }

  .error-msg {
    color: #ff3366;
    font-size: 13px;
    margin-top: 10px;
    min-height: 15px;
    text-shadow: 0 0 5px rgba(255, 51, 102, 0.5);
  }

  /* Spinner CSS */
  .spinner {
    width: 20px;
    height: 20px;
    border: 3px solid rgba(255,255,255,0.3);
    border-top-color: var(--text-white);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    display: none;
  }

  @keyframes spin { 100% { transform: rotate(360deg); } }
  
  .oculto { display: none !important; }
</style>