todo.css

body{
    background-color: darkcyan;
    margin-bottom: 100px;
}
#container{             
    /* margin:auto; */
    text-align: center;
    /* border: 2px solid crimson; */
    /* height:400px; */
    width: 90%;
}
.button{
    height:40px;
    width:150px;
}
#input{
    margin-top:10px;
    height:30px;
    width:50%;
    font-family: 'Courier New', Courier, monospace;
    font-style: initial;
}
.button{
    margin-top:10px;
    color:white;
    background-color: green;
}
#editButton {
    background-color: darkslategray;
    float: right;
    height:30px;
    width: 70px;
    cursor: pointer;
    opacity:0;
    background-color: black;
    color: white;
}
.button:hover{
  background-color:black;
  font-size: 18px;
}
#container ul li{
    list-style: none;
    border:0.5px solid cornflowerblue;
    text-align: left;
    /* margin: 2px auto ; */
    /* height: 40px; */
    /* for comes in/out smoothly */
    transition: opacity 0.5s ease-in-out; 
    opacity: 0;
    width:90%; 
    /* float: left; */
}
#container ul li#firstList {
    border : 0.5px solid darkcyan;
}

#container ul li label{
    /* margin: 0 auto; */
    /* height: 100%; */
    font-size: 16px;
    vertical-align: middle;
    line-height: 40px;
    /* width:100%;  */
    /* border: 1px solid green; */
}
#container .listItem{
    opacity: 1;
}
 #container ul li #checkBox{
    width:30px;
    height: 30px;
    float: left;
    vertical-align: middle;
    border: 1px solid black;
    -webkit-appearance: none;
}
#container ul li input[name="hideCheckBox"] {
    opacity: 0;          
      /* for first checkbox */ 
}

#container ul li #dateAndTime {

    /* margin-left: 100px; */
    float: right;
    /* border: 2px solid red; */
    /* width: 200px; */
}
 #container ul li #checkBox:checked:after {
     content: '\2714';
     position: absolute;
     color: blue;
     font-size: 26px;
 }
 #container ul li input[type="checkBox"]:checked + label {
     text-decoration: line-through;
     color:white;
     opacity: 0.4;
}

#container .controls #input:focus {
    outline: 0;
}
#container #controls button {
    cursor: pointer;
}
#container #controls button:hover {
    transform: scale(1.07)
}
#container .listItem {
opacity: 1;
}
.visual{
    opacity: 1 !important;
    vertical-align: middle;
}
/* // for showing button */
.editClassButton {             
    opacity: 1 !important;
    vertical-align: middle; 
}

html {
    position: relative;
    min-height: 100%;
}

#footer {
    background-color: dimgray;
    left: 0;
    bottom: 0;
    position: absolute;
    color:white;
    text-align: center;
    opacity: 0.4;
    width: 100%;
    height: 50px; 
    /* //same height as the margin to the bottom of the body */
}