Close dropdown one when other is opened - html

Question

I have created drop-down which is working properly but it's not closing when opening other. I need to close one when other is opened. It should be done through CSS only, no JS. So, I need a fix so all of them work independently. I have tried but couldn't do it. I am posting the HTML and CSS code below please have look. Please help me to fix it.
#import url('https://fonts.googleapis.com/css2?family=Roboto:wght#400;500;700;900&display=swap');
*,
*::before,
*::after {
box-sizing: border-box;
}
body {
font-family: 'Roboto', sans-serif;
font-weight: 500;
font-size: 15px;
line-height: 1.4;
color: #fff;
background-color: #1f2029;
overflow-x: hidden;
background-image: url('https://s3-us-west-2.amazonaws.com/s.cdpn.io/1462889/pat-back.svg');
background-position: center;
background-repeat: repeat;
background-size: 4%;
width: 100%;
display: -ms-flexbox;
display: flex;
-ms-flex-wrap: wrap;
flex-wrap: wrap;
-ms-flex-pack: center;
justify-content: center;
padding-top: 100px;
padding-bottom: 300px;
}
.sec-center,
.sec-center1,
.sec-center2 {
position: relative;
max-width: 100%;
text-align: center;
z-index: 200;
display: inline-block;
margin-right: 5px;
}
[type="checkbox"]:checked,
[type="checkbox"]:not(:checked) {
position: absolute;
left: -9999px;
opacity: 0;
pointer-events: none;
}
.dropdown:checked+label,
.dropdown:not(:checked)+label,
.dropdown1:checked+label,
.dropdown1:not(:checked)+label,
.dropdown2:checked+label,
.dropdown2:not(:checked)+label {
position: relative;
font-family: calibri, sans-serif;
font-weight: 500;
font-size: 14px;
/* line-height: 2; */
/* height: 50px; */
transition: all 200ms linear;
/* border-radius: 4px; */
/* width: 220px; */
letter-spacing: 1px;
display: -webkit-inline-flex;
display: -ms-inline-flexbox;
display: inline-flex;
-webkit-align-items: center;
-moz-align-items: center;
-ms-align-items: center;
align-items: center;
-webkit-justify-content: center;
-moz-justify-content: center;
-ms-justify-content: center;
justify-content: center;
-ms-flex-pack: center;
text-align: center;
border: none;
background-color: transparent;
cursor: pointer;
color: #fff;
/* box-shadow: 0 12px 35px 0 rgb(255 235 167 / 15%); */
padding: 4px 20px;
border-right: 2px solid #fff;
border-radius: 50px;
}
.dropdown:checked+label:before,
.dropdown:not(:checked)+label:before,
.dropdown1:checked+label:before,
.dropdown1:not(:checked)+label:before,
.dropdown2:checked+label:before,
.dropdown2:not(:checked)+label:before {
position: fixed;
top: 0;
left: 0;
content: '';
width: 100%;
height: 100%;
z-index: -1;
cursor: auto;
pointer-events: none;
}
.dropdown:checked+label:before,
.dropdown1:checked+label:before,
.dropdown2:checked+label:before {
pointer-events: auto;
}
.dropdown:not(:checked)+label .uil,
.dropdown1:not(:checked)+label .uil,
.dropdown2:not(:checked)+label .uil {
content: '';
position: absolute;
right: 6px;
transform: rotate(0deg);
width: 0;
height: 0;
border-left: 4px solid transparent;
border-right: 4px solid transparent;
border-top: 4px solid #fff;
}
.dropdown:checked+label .uil,
.dropdown1:checked+label .uil,
.dropdown2:checked+label .uil {
content: '';
position: absolute;
right: 6px;
transform: rotate(180deg);
width: 0;
height: 0;
border-left: 4px solid transparent;
border-right: 4px solid transparent;
border-top: 4px solid #fff;
}
.dropdown:checked~.section-dropdown,
.dropdown1:checked~.section-dropdown1,
.dropdown2:checked~.section-dropdown2 {
opacity: 1;
pointer-events: auto;
transform: translateY(0);
}
/* .dropdown:checked+label,
.dropdown:not(:checked)+label:hover {
color: #000;
background-color: #FBBC05;
} */
.section-dropdown,
.section-dropdown1,
.section-dropdown2 {
position: absolute;
padding: 5px;
background-color: #004287;
top: 41px;
left: 0;
width: 100%;
border-radius: 4px;
display: block;
/* box-shadow: 0 14px 35px 0 rgba(9, 9, 12, 0.4); */
z-index: 2;
opacity: 0;
pointer-events: none;
transform: translateY(20px);
transition: all 200ms linear;
}
.section-dropdown:before,
.section-dropdown1:before,
.section-dropdown2:before {
position: absolute;
top: -20px;
left: 0;
width: 100%;
height: 20px;
content: '';
display: block;
z-index: 1;
}
.section-dropdown:after,
.section-dropdown1:after,
.section-dropdown2:after {
position: absolute;
top: -7px;
left: 30px;
width: 0;
height: 0;
border-left: 8px solid transparent;
border-right: 8px solid transparent;
border-bottom: 8px solid #c82333;
content: '';
display: block;
z-index: 2;
transition: all 200ms linear;
}
.section-dropdown a,
.section-dropdown1 a,
.section-dropdown2 a {
position: relative;
color: #fff;
transition: all 200ms linear;
font-family: calibri, sans-serif;
font-weight: 500;
font-size: 14px;
border-radius: 2px;
padding: 5px 0;
padding-left: 20px;
padding-right: 15px;
margin: 2px 0;
text-align: left;
text-decoration: none;
display: -ms-flexbox;
display: flex;
-webkit-align-items: center;
-moz-align-items: center;
-ms-align-items: center;
align-items: center;
justify-content: space-between;
-ms-flex-pack: distribute;
}
.section-dropdown a:hover,
.section-dropdown1 a:hover,
.section-dropdown2 a:hover {
color: #000;
background-color: #FBBC05;
}
.section-dropdown a .uil,
.section-dropdown1 a .uil,
.section-dropdown2 a .uil {
font-size: 22px;
}
.dropdown-sub:checked+label,
.dropdown-sub:not(:checked)+label,
.dropdown-sub1:checked+label,
.dropdown-sub1:not(:checked)+label,
.dropdown-sub2:checked+label,
.dropdown-sub2:not(:checked)+label {
position: relative;
color: #fff;
transition: all 200ms linear;
font-family: calibri, sans-serif;
font-weight: 500;
font-size: 14px;
border-radius: 2px;
padding: 5px 0;
padding-left: 20px;
padding-right: 15px;
text-align: left;
text-decoration: none;
display: -ms-flexbox;
display: flex;
-webkit-align-items: center;
-moz-align-items: center;
-ms-align-items: center;
align-items: center;
justify-content: space-between;
-ms-flex-pack: distribute;
cursor: pointer;
}
.dropdown-sub:checked+label .uil,
.dropdown-sub:not(:checked)+label .uil,
.dropdown-sub1:checked+label .uil,
.dropdown-sub1:not(:checked)+label .uil,
.dropdown-sub2:checked+label .uil,
.dropdown-sub2:not(:checked)+label .uil {
font-size: 22px;
}
.dropdown-sub:not(:checked)+label .uil,
.dropdown-sub1:not(:checked)+label .uil,
.dropdown-sub2:not(:checked)+label .uil {
content: '';
position: absolute;
right: 6px;
transform: rotate(0deg);
width: 0;
height: 0;
border-left: 4px solid transparent;
border-right: 4px solid transparent;
border-top: 4px solid #fff;
}
.dropdown-sub:checked+label .uil,
.dropdown-sub1:checked+label .uil,
.dropdown-sub2:checked+label .uil {
content: '';
position: absolute;
right: 6px;
transform: rotate(180deg);
width: 0;
height: 0;
border-left: 4px solid transparent;
border-right: 4px solid transparent;
border-top: 4px solid #fff;
}
.dropdown-sub:checked+label:hover,
.dropdown-sub:not(:checked)+label:hover,
.dropdown-sub1:checked+label:hover,
.dropdown-sub1:not(:checked)+label:hover,
.dropdown-sub2:checked+label:hover,
.dropdown-sub2:not(:checked)+label:hover {
color: #000;
background-color: #FBBC05;
}
.section-dropdown-sub,
.section-dropdown-sub1,
.section-dropdown-sub2 {
position: relative;
display: block;
width: 100%;
pointer-events: none;
opacity: 0;
max-height: 0;
padding-left: 10px;
padding-right: 3px;
overflow: hidden;
transition: all 200ms linear;
}
.dropdown-sub:checked~.section-dropdown-sub,
.dropdown-sub1:checked~.section-dropdown-sub1,
.dropdown-sub2:checked~.section-dropdown-sub2 {
pointer-events: auto;
opacity: 1;
max-height: 999px;
}
.section-dropdown-sub a,
.section-dropdown-sub1 a,
.section-dropdown-sub2 a {
font-size: 14px;
}
.section-dropdown-sub a .uil,
.section-dropdown-sub1 a .uil,
.section-dropdown-sub2 a .uil {
font-size: 20px;
}
<div class="sec-center">
<input class="dropdown" type="checkbox" id="dropdown" name="dropdown" />
<label class="for-dropdown" for="dropdown">Train Services<i class="uil uil-arrow-down"></i></label>
<div class="section-dropdown">
Inside Dropdown Link 1 <i class="uil uil-arrow-right"></i>
<input class="dropdown-sub" type="checkbox" id="dropdown-sub" name="dropdown-sub" />
<label class="for-dropdown-sub" for="dropdown-sub">Dropdown Sub 1 <i class="uil uil-plus"></i></label>
<div class="section-dropdown-sub">
Dropdown Sub Link 1 <i class="uil uil-arrow-right"></i>
Dropdown Sub Link <i class="uil uil-arrow-right"></i>
</div>
Inside Dropdown Link 1 <i class="uil uil-arrow-right"></i>
Inside Dropdown Link 1 <i class="uil uil-arrow-right"></i>
</div>
</div>
<div class="sec-center1">
<input class="dropdown1" type="checkbox" id="dropdown1" name="dropdown1" />
<label class="for-dropdown1" for="dropdown1">Category<i class="uil uil-arrow-down"></i></label>
<div class="section-dropdown1">
Inside Dropdown Link 2 <i class="uil uil-arrow-right"></i>
<input class="dropdown-sub1" type="checkbox" id="dropdown-sub1" name="dropdown-sub1" />
<label class="for-dropdown-sub1" for="dropdown-sub1">Dropdown Sub 2 <i class="uil uil-plus"></i></label>
<div class="section-dropdown-sub1">
Dropdown Sub Link 2<i class="uil uil-arrow-right"></i>
Dropdown Sub Link <i class="uil uil-arrow-right"></i>
</div>
Inside Dropdown Link 2 <i class="uil uil-arrow-right"></i>
Inside Dropdown Link 3 <i class="uil uil-arrow-right"></i>
</div>
</div>
<div class="sec-center2">
<input class="dropdown2" type="checkbox" id="dropdown2" name="dropdown2" />
<label class="for-dropdown2" for="dropdown2">Author<i class="uil uil-arrow-down"></i></label>
<div class="section-dropdown2">
Inside Dropdown Link 2 <i class="uil uil-arrow-right"></i>
<input class="dropdown-sub2" type="checkbox" id="dropdown-sub2" name="dropdown-sub2" />
<label class="for-dropdown-sub2" for="dropdown-sub2">Dropdown Sub 2 <i class="uil uil-plus"></i></label>
<div class="section-dropdown-sub2">
Dropdown Sub Link 2<i class="uil uil-arrow-right"></i>
Dropdown Sub Link <i class="uil uil-arrow-right"></i>
</div>
Inside Dropdown Link 2 <i class="uil uil-arrow-right"></i>
Inside Dropdown Link 3 <i class="uil uil-arrow-right"></i>
</div>
</div>