Cabecera: header

Reglas aplicadas:

  <style type="text/css">
    #caja header h1 { color: blue;  } /*(1) A = 0, B = 1, C = 0, D = 2 (102) */
    h1 { color: purple;  } /*(2) A = 0, B = 0, C = 0, D = 1 (1) */
    h1 { color: grey;  } /*(3) A = 0, B = 0, C = 0, D = 1 (1) */
    header h1 { color: lime;  } /*(4) A = 0, B = 0, C = 0, D = 2 (2) */
    #caja .cabecera h1 { color: red;  } /*(5) A = 0, B = 1, C = 1, D = 1 (111) => REGLA CON MAYOR PRIORIDAD */
  </style>