using Microsoft.AspNetCore.Mvc;
using System.Collections.Generic;

namespace YourNamespace.Controllers
{
    [ApiController]
    [Route("[controller]")]
    public class LoginController : ControllerBase
    {
        private static readonly Dictionary<string, string> Users = new Dictionary<string, string>
        {
            {"admin", "admin"},
            {"dsfsdf", "sdfsdf"}
        };

        [HttpPost]
        public IActionResult Post([FromBody] LoginRequest request)
        {
            if (Users.TryGetValue(request.Login, out var password) && password == request.Password)
            {
                return Ok(new { access = true });
            }

            return Ok(new { access = false });
        }
    }

    public class LoginRequest
    {
        public string Login { get; set; }
        public string Password { get; set; }
    }
}

using Microsoft.AspNetCore.Mvc;
using System.Collections.Generic;

namespace YourNamespace.Controllers
{
    [ApiController]
    [Route("[controller]")]
    public class LoginController : ControllerBase
    {
        private static readonly Dictionary<string, string> Users = new Dictionary<string, string>
        {
            {"admin", "admin"},
            {"dsfsdf", "sdfsdf"}
        };

        [HttpPost]
        public IActionResult Post([FromBody] LoginRequest request)
        {
            if (Users.TryGetValue(request.Login, out var password) && password == request.Password)
            {
                return Ok(new { access = true });
            }

            return Ok(new { access = false });
        }
    }

    public class LoginRequest
    {
        public string Login { get; set; }
        public string Password { get; set; }
    }
}

body {
    margin: 0px;
    padding:0px;
    box-sizing:border-box;
    user-select:none;
}

.wrapper {
    margin: 200px auto 0 auto;
    padding: 30px;
    border: 2px solid #808080;
    border-radius: 5px;
    width: 50%;
}

    .wrapper input {
        border: 1px solid #808080;
        border-radius: 3px;
        font-size: 16px;
        letter-spacing: 2px;
        background-color: #dcdcdc;
        width: 80%;
        margin: 50px auto;
        padding: 5px;
        outline: none;
    }

#submit {
    display: block;
    width: 100px;
    cursor: pointer;
    background-color: #9bffa6;
    border: none;
    outline: none;
    padding: 10px;
    border-radius: 5px;
}

#submit:hover {
    transition: .5s all ease;
    background-color:#67fa3d;
}

#result {
    width:120px;
    background-color:#97f5ef;
    padding:10px 20px;
    margin:50px auto;
    text-align:center;
    border-radius:5px;
}

#result input{
    width:100%;
    height:100%;
    margin:0;
    padding:0;
    background-color:transparent;
    border:none;
    outline:none;
    user-select:none;
    text-align:center;
}

body {
    margin: 0px;
    padding:0px;
    box-sizing:border-box;
    user-select:none;
}

.wrapper {
    margin: 200px auto 0 auto;
    padding: 30px;
    border: 2px solid #808080;
    border-radius: 5px;
    width: 50%;
}

    .wrapper input {
        border: 1px solid #808080;
        border-radius: 3px;
        font-size: 16px;
        letter-spacing: 2px;
        background-color: #dcdcdc;
        width: 80%;
        margin: 50px auto;
        padding: 5px;
        outline: none;
    }

#submit {
    display: block;
    width: 100px;
    cursor: pointer;
    background-color: #9bffa6;
    border: none;
    outline: none;
    padding: 10px;
    border-radius: 5px;
}

#submit:hover {
    transition: .5s all ease;
    background-color:#67fa3d;
}

#result {
    width:120px;
    background-color:#97f5ef;
    padding:10px 20px;
    margin:50px auto;
    text-align:center;
    border-radius:5px;
}

#result input{
    width:100%;
    height:100%;
    margin:0;
    padding:0;
    background-color:transparent;
    border:none;
    outline:none;
    user-select:none;
    text-align:center;
}