Gracias por responder, estoy intentando, pero no logro que funcione, creo que el problema esta en el css del modal
  
Código:
 <style>
.modal-container {
}
.modal-container .modal-backdrop {
  height: 0;
  width: 0;
  opacity: 0;
  overflow: hidden;
  transition: opacity 0.2s ease-in;
}
.modal-container #modal-toggle {
  position: absolute;
  left: 0;
  top: 0;
  height: 100%;
  width: 100%;
  margin: 0;
  opacity: 0;
  cursor: pointer;
}
.modal-container #modal-toggle:checked {
  width: 100vw;
  height: 100vh;
  position: fixed;
  left: 0;
  top: 0;
  z-index: 999;
  opacity: 0;
}
.modal-container #modal-toggle:checked ~ .modal-backdrop {
  background-color: rgba(0, 0, 0, 0.6);
  width: 100vw;
  height: 100vh;
  position: fixed;
  left: 0;
  top: 0;
  z-index: 999;
  pointer-events: none;
  cursor: default;
  opacity: 1;
}
.modal-container #modal-toggle:checked ~ .modal-backdrop .modal-content {
  background-color: #fff;
  width: 90%;
  height: 100%;
  padding: 10px 30px;
  position: absolute;
  left: 0px;
  top: 0px;
  border-radius: 4px;
  z-index: 999;
  pointer-events: auto;
  margin-left: 5%;
  margin-right: 5%;
  margin-top: 30px;
  box-shadow: 0 3px 7px rgba(0, 0, 0, 0.6);
  overflow: scroll;
  overflow-x: hidden;
  border-radius: 3px;
}
@media (max-width: 400px) {
.modal-container #modal-toggle:checked ~ .modal-backdrop .modal-content { left: 0; }
}
.modal-container #modal-toggle:checked ~ .modal-backdrop .modal-content .modal-close {
  color: #666;
  position: absolute;
  right: 2px;
  top: 0;
  padding-top: 7px;
  background: #fff;
  font-size: 16px;
  width: 25px;
  height: 28px;
  font-weight: bold;
  text-align: center;
  cursor: pointer;
}
.modal-container #modal-toggle:checked ~ .modal-backdrop .modal-content .modal-close.button {
  top: initial;
  bottom: 20px;
  right: 20px;
  background: #4CAF50;
  color: #fff;
  width: 50px;
  border-radius: 2px;
  font-size: 14px;
  font-weight: normal;
}
.modal-container #modal-toggle:checked ~ .modal-backdrop .modal-content .modal-close.button:hover {
  color: #fff;
  background: #1E824C;
}
.modal-container #modal-toggle:checked ~ .modal-backdrop .modal-content .modal-close:hover { color: #333; }
</style>
  
instalando otros tipos de modal tampoco funciona, modal con javascript tampoco, no se que puede estar ocurriendo. 
Alguna idea?