Create a admin log in page on blogger

 Put the codes before - ]]></b:skin>

.thotbuzzloginwrap{width:100%;height:100%;position:fixed;left:0;top:0;z-index:9999999999;background:linear-gradient(-45deg,#23a6d5,#23d5ab,#f09800,#e6af19);background-size:400% 400%;animation:gradient 10s ease infinite}
@keyframes gradient{0%{background-position:0% 50%}50%{background-position:100% 50%}100%{background-position:0% 50%}}
.thotbuzzloginwrap.hidden{display: none}
#thotbuzzlogin{position:absolute;border-radius:8px;width:400px;padding:30px;display:block;transform:translate(-50%,-50%);top:50%;left:50%;background:rgba(255,255,255,0.1);backdrop-filter:blur(5px);border-radius:10px;box-shadow:0 25px 45px rgba(0,0,0,0.2);color:#fff}
.thotbuzzjudul{font-size:25px;font-weight: bold;}
#thotbuzzlogin input[type="text"],#thotbuzzlogin input[type="password"]{padding:10px;border-radius:5px;margin:10px 0;width:95%;border:1px solid rgba(255,255,255,0.2);background:rgba(255,255,255,0.2);color:#fff}
#username::-webkit-input-placeholder,#password::-webkit-input-placeholder{color:#fff;}
#thotbuzzlogin input[type="text"]:focus,#thotbuzzlogin input[type="password"]:focus{outline:none}
button.login{color:#000;font-weight:bold;padding:10px;border-radius:5px;border:none;outline:none;border: 1px solid rgba(255, 255, 255, 0.2);background:#fff;transition: 1.5s}
button.login:hover{background: rgba(255, 255, 255, 0.2);color:#fff;transition: .5s}
.icon1{position:absolute;margin-top:20px;right:55px;z-index: 1}
.icon2{position:absolute;margin-top:20px;right:55px;opacity: 0}
svg.thotbuzz{width:24px;height::24px;fill:#fff}
@media screen and (max-width:480px){#thotbuzzlogin{width:350px}}

Put the codes before  </body> tag

<script>
//<![CDATA[
// last update 20-04-2022 + localStroge
var storeS = localStorage.getItem("users");
if(storeS==null){
  var users = [
    { username: "admin", password: "12345" }];
    localStorage.setItem("users",JSON.stringify(users));
}
function getUserUsername(username) {
    return JSON.parse(localStorage.getItem('users')).filter(users => users.username === username)
}
function ceklog(){
  var login = localStorage.getItem("login");
  if(login!=null && login=="true"){
document.querySelector(".thotbuzzloginwrap").classList.add("hidden");        
      }
    }
ceklog();

function startlog(){
  var username= document.querySelector("#username").value;
  var password= document.querySelector("#password").value;
   
 if(getUserUsername(username.trim()).length>0){
   var user = getUserUsername(username.trim())[0];
   if(user.password == password.trim()){
     document.querySelector(".thotbuzzloginwrap").classList.add("hidden");
     localStorage.setItem("login","true");
     }else{       
       document.querySelector("#akses").innerHTML = "nome de usuário ou senha errada!";
      }
    }else{
      document.querySelector("#akses").innerHTML = "usuário não registrado";
    }
  }
  
const show = () =>{
  var password = document.querySelector("#password");
  var sandi = document.querySelector(".icon1");
  var sandidua = document.querySelector(".icon2");
  if (password.type === "password"){
    password.type = "text";
    sandidua.style.opacity = "1";
    sandi.style.opacity = "0";
  }else{
    password.type = "password";
    sandidua.style.opacity = "0";
    sandi.style.opacity = "1";
  }
}
//]]> 
</script>

Go to the static post or page where you want to set the password, switch to HTML view, copy and paste the following HTML code and save.


<dv class='thotbuzzloginwrap'>
<div id='thotbuzzlogin'>
<div class='thotbuzzjudul'>Login</div>
<input id='username' placeholder='Usuario' type='text'/><br/>
<input id='password' placeholder='senha' type='password'/>
<svg class='thotbuzz icon1' onclick='show()' viewBox='0 0 24 24'>
<path d='M12,9A3,3 0 0,0 9,12A3,3 0 0,0 12,15A3,3 0 0,0 15,12A3,3 0 0,0 12,9M12,17A5,5 0 0,1 7,12A5,5 0 0,1 12,7A5,5 0 0,1 17,12A5,5 0 0,1 12,17M12,4.5C7,4.5 2.73,7.61 1,12C2.73,16.39 7,19.5 12,19.5C17,19.5 21.27,16.39 23,12C21.27,7.61 17,4.5 12,4.5Z'/></svg>
<svg class='thotbuzz icon2' viewBox='0 0 24 24'>
<path d='M11.83,9L15,12.16C15,12.11 15,12.05 15,12A3,3 0 0,0 12,9C11.94,9 11.89,9 11.83,9M7.53,9.8L9.08,11.35C9.03,11.56 9,11.77 9,12A3,3 0 0,0 12,15C12.22,15 12.44,14.97 12.65,14.92L14.2,16.47C13.53,16.8 12.79,17 12,17A5,5 0 0,1 7,12C7,11.21 7.2,10.47 7.53,9.8M2,4.27L4.28,6.55L4.73,7C3.08,8.3 1.78,10 1,12C2.73,16.39 7,19.5 12,19.5C13.55,19.5 15.03,19.2 16.38,18.66L16.81,19.08L19.73,22L21,20.73L3.27,3M12,7A5,5 0 0,1 17,12C17,12.64 16.87,13.26 16.64,13.82L19.57,16.75C21.07,15.5 22.27,13.86 23,12C21.27,7.61 17,4.5 12,4.5C10.6,4.5 9.26,4.75 8,5.2L10.17,7.35C10.74,7.13 11.35,7 12,7Z'/>
</svg>
<br/>
<button class='login' onclick='startlog()'>Login</button>
<p id='akses'/>
</div>
</dv>