batharoy

@hoyinli
https://www.ads-software.com/themes/syntax
https://www.ads-software.com/themes/runo-lite
https://www.ads-software.com/themes/serena
https://www.ads-software.com/themes/litesta
https://www.ads-software.com/themes/mybook

For the grey lines:

nav#main-nav > ul:before, nav#main-nav > ul:after {
    background: none;
}

For the menu there is a pure css way but would require the menu be moved to the top of the page.

#nav-wrapper {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background: #fff;
    z-index: 9999;
}
#header-wrap {
    margin-top: 50px;
}

It is possible but requires a child-theme as you would need to edit the header.php file.

Whispy is whats called a fixed width theme. If the browser goes below 995px in width you end up with a horizontal scrollbar.

Child-themes are easy to set up and offer great flexibility, they are pretty much required for any php file edits. Since you are only changing css styles you could also use a custom css plugin if that seems easier.

#page:before, #page:after, #header, #main {
    background-image: none;
}

Try this:

article.post {
    border-bottom: none
};

This would need edits to the header.php file and requires a child-theme.

Try .site-info instead of generator.

This can be done with .date{display: none;}
As you can guess by the selector it will hide the date aswell.
If you want only the name you will need to copy the single.php to the child-theme and remove the following bit of code.

by <?php the_author(); ?>

Would be advisable for me to make the jump to a more recent theme?

The theme has only been updated once in over 2 years, that was 9 months ago, your call.

When looking at the page source, the body tag has a class of singular-page-566.
Have you tried targeting that?

Try applying the background to the masthead instead of the hgroup.

#masthead {
    background: url('https://www.atm-411.com/wp-content/uploads/2014/02/atm-triton-banner.jpg') no-repeat transparent;
    background-position: top right;
    border: none;
}

What exactly is not right?
Can you link screenshots so we have an idea of what your looking to do?

I can see that the entry content is blue as you specified.
Your html output does not have any selector of a.home.link
What exactly is it you want red?

.site-branding h1, .site-branding h2 {
    margin-left: 40px;
}