body {
  margin: 0;
  background-color: #f3f4f6;
  font-family: Montserrat, Arial, sans-serif;
  background-image: url('fondo.jpg');
  background-size: cover;
  background-repeat: no-repeat;
  background-attachment: fixed;
}

/* cabecera */

header {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 105px;
  background-color: white;
}

h1 {
  position: absolute;
  top: 21%;
  left: 1.7%;
  margin: 0;
  font-size: 40px;
  font-weight: 300;
  color: #162b4d;
}

.menu {
  position: absolute;
  top: 17%;
  width: 12.1%;
  height: 65%;
  background-color: #c8d0db;
  color: white;
  font-size: 13px;
  font-weight: bold;
  text-decoration: none;
  text-align: center;
  line-height: 68px;
}

.menu:hover {
  background-color: #2563a8;
}

#profesores { 
  left: 55.3%; 
}
#asignaturas { 
  left: 70%; 
}
#cerrar{ 
  left: 84.7%; 
}

/* tabla */

table {
  position: absolute;
  top: 139px;
  left: 1.5%;
  width: 74%;
  border-collapse: collapse;
  background-color: white;
}

thead td {
  height: 53px;
  padding: 0 15px;
  background-color: #162b4d;
  color: white;
  font-size: 40px;
}

th {
  width: 17.2%;
  height: 54px;
  border: 1px solid #3b72b4;
  background-color: #2563a8;
  color: white;
  font-size: 15px;
}

.horas {
  width: 14%;
}

tbody td {
  height: 54px;
  padding: 0;
  border: 1px solid #e3e6ea;
  font-size: 14px;
}

tbody td:first-child {
  padding: 0 6px;
  font-weight: bold;
}

select {
  width: 100%;
  height: 100%;
  border: none;
  background-color: white;
  color: #2563a8;
  font-family: inherit;
  font-size: 13px;
}

select:hover {
  background-color: #e8f0fa;
}

option {
  color: #162b4d;
}

/* cuadro */

.cuadro {
  position: absolute;
  top: 139px;
  left: 78%;
  width: 20%;
  height: 195px;
  background-color: white;
  box-shadow: 5px 5px 10px rgba(0, 0, 0, 0.3);
}

input {
  position: absolute;
  left: 10%;
  width: 80%;
  height: 50px;
  border: none;
  border-radius: 25px;
  color: white;
  font-family: inherit;
  font-size: 18px;
}

#guardar {
  top: 40px;
  background-color: #2563a8;
}

#guardar:hover {
  background-color: #3a7bc8;
}

#borrar {
  top: 105px;
  background-color: #162b4d;
}

#borrar:hover {
  background-color: #2b4a7a;
}