.code-input {
    width: 40px;
    height: 40px;
    text-align: center;
    font-size: 20px;
    border: 2px solid #7291c3;
    border-radius: 8px;
    background: #eef4ff;
    margin: 0 3px;
    transition: border-color 0.2s;
}

    .code-input:focus {
        border-color: #0a2971;
        outline: none;
    }