need to hide that nighmode checkbox mark and make that slider clickable to toggle nighmodes by clicking on it (slider) by preserving CSS-only functionality: <style>
.switch-container input[type="checkbox"] {
position: absolute;
width: 1px;
height: 1px;
opacity: 0;
}

.switch-container input[type="checkbox"]:checked ~ label:before {
opacity: 1;
}

body, html {
margin: 0;
padding: 0;
height: 100%;
line-height: 1.6;
background-color: #f7f7f7;
transition: background-color .5s, color .5s;
}

header {
background-color: #4CAF50;
color: #FFF;
padding: 16px 0px 0px 0px;
text-align: center;
position: relative;
transition: background-color .5s;
}

h1, h2, h3, h4, h5, h6 {
margin: 0 auto;
display: flex;
justify-content: space-between;
align-items: center;
font-size: 18px;
width: 90%;
height: 1%;
}

.left, .right {
position: relative;
}

.left::before, .right::before {
content: '';
position: absolute;
top: 50%;
border-bottom: 1px dashed #FFF;
width: 40%;
}

.left::before {
right: 100%;
margin-right: 20px;
}

.right::before {
left: 100%;
margin-left: 20px;
}

.flags-container {
position: relative;
top: 0;
right: 10px; 
--padding: 3px 0;
background-color: white;
display: flex;
justify-content: center;
align-items: center;
--box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
z-index: 1;
}

.flag-radio {
display: none;
}

.flag-label {
cursor: pointer;
margin: 0 10px;
transition: 0.3s;
opacity: 0.6;
font-size: 24px;
}

.flag-label:hover {
opacity: 1;
}

.language-option {
position: run-in;
top: 0;
left: 0;
right: 0;
bottom: 0;
display: none;
justify-content: center;
align-items: center;
padding-top: 0px;
}

#english-flag:checked ~ #english,
#hindi-flag:checked ~ #hindi,
#hebrew-flag:checked ~ #hebrew,
#chinese-flag:checked ~ #chinese,
#french-flag:checked ~ #french,
#spanish-flag:checked ~ #spanish {
display: block;
}

#night-mode-toggle:checked ~ body,
#night-mode-toggle:checked ~ header,
#night-mode-toggle:checked ~ .language-option {
background-color: #333;
color: #FFF;
}

#night-mode-toggle:checked ~ .flags-container {
background-color: #444;
}

#night-mode-toggle:checked ~ .switch-container label {
color: #FFF;
}

.switch-container {
position: absolute;
top: 0;
right: 80px; 
display: flex;
align-items: center;
z-index: 2; 
}

.switch {
position: relative; 
cursor: pointer;
width: 60px;
height: 30px;
background-color: #FFF;
border-radius: 15px;
transition: background-color .5s;
}

.switch:before {
content: '';
display: block;
position: absolute;
top: 2px;
left: 2px;
height: 26px;
width: 26px;
background-color: #333;
border-radius: 50%;
transition: left .3s;
}

#night-mode-toggle:checked ~ .switch-container .switch {
background-color: #444;
}

#night-mode-toggle:checked ~ .switch-container .switch:before {
left: calc(100% - 28px);
}
</style>
</head>
<body>


<input id="english-flag" type="radio" name="flags" class="flag-radio">
<input id="hindi-flag" type="radio" name="flags" class="flag-radio">
<input id="hebrew-flag" type="radio" name="flags" class="flag-radio">
<input id="chinese-flag" type="radio" name="flags" class="flag-radio">
<input id="french-flag" type="radio" name="flags" class="flag-radio">
<input id="spanish-flag" type="radio" name="flags" class="flag-radio">

<div class="flags-container">
<label for="english-flag" class="flag-label">????</label>
<label for="hindi-flag" class="flag-label">????</label>
<label for="hebrew-flag" class="flag-label">????</label>
<label for="chinese-flag" class="flag-label">????</label>
<label for="french-flag" class="flag-label">????</label>
<label for="spanish-flag" class="flag-label">????</label>
</div><br>

<header>
<h1>
<span class="left">EcoWare</span>
<span class="right">Earthwise</span>
</h1>
</header>
<!-- Night Mode Switch -->
<input type="checkbox" id="night-mode-toggle" />
<div class="switch-container">
<label for="night-mode-toggle">Save the energy!</label>
<div class="switch"></div>
</div>
<div id="english" class="language-option">
<p>english details going here</p>
</div>

<div id="hindi" class="language-option">
<p>hindi details going here</p>
</div>

<div id="hebrew" class="language-option">
<p>hebrew details going here</p>
</div>

<div id="chinese" class="language-option">
<p>chinese details going here</p>
</div>

<div id="french" class="language-option">
<p>french details going here</p>
</div>

<div id="spanish" class="language-option">
<p>spanish details going here</p>
</div>
</body>
</html>