* {
    box-sizing: border-box;
}

:root {
    font-family: Arial, Helvetica, sans-serif;
    color: #171717;
    background: #ffffff;
}

body {
    margin: 0;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 28px 20px;
    background: #ffffff;
}

.login-card {
    width: 100%;
    max-width: 390px;
    margin: auto;
    padding: 28px 18px 32px;
}

/* Logo tròn, căn giữa */
.logo {
    width: 156px;
    height: 156px;
    margin: 0 auto 48px;
    border: 2px solid #222222;
    border-radius: 50%;
    overflow: hidden;
    display: flex;
    align-items: center;
    justify-content: center;
    background: #ffffff;
}

.logo img {
    display: block;
    width: 100%;
    height: 100%;
    object-fit: contain;
    border-radius: 50%;
}

/* Các trường nhập */
.form-group {
    display: flex;
    flex-direction: column;
    gap: 10px;
    margin-bottom: 30px;
}

label {
    font-size: 17px;
    font-weight: 600;
    line-height: 1.4;
    color: #222222;
}

input {
    width: 100%;
    height: 48px;
    padding: 8px 4px;
    border: none;
    border-bottom: 2px solid #222222;
    border-radius: 0;
    outline: none;
    background: transparent;
    color: #171717;
    font-size: 17px;
    transition: border-color 0.2s;
}

input:focus {
    border-bottom-color: #2457a7;
    border-bottom-width: 3px;
}

/* Nút đăng nhập */
button {
    width: 100%;
    min-height: 58px;
    margin-top: 12px;
    padding: 12px 20px;
    border: 2px solid #222222;
    border-radius: 5px;
    background: #ffffff;
    color: #171717;
    font-family: inherit;
    font-size: 17px;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.2s, color 0.2s;
}

button:hover {
    background: #222222;
    color: #ffffff;
}

button:active {
    transform: translateY(1px);
}

button:focus-visible,
input:focus-visible {
    outline: 2px solid #2457a7;
    outline-offset: 3px;
}

#message {
    margin: 14px 0 0;
    text-align: center;
    font-size: 14px;
    line-height: 1.5;
}

@media (max-width: 480px) {
    .login-card {
        max-width: 360px;
        padding-right: 8px;
        padding-left: 8px;
    }

    .logo {
        width: 142px;
        height: 142px;
        margin-bottom: 38px;
    }
}