How to Make an Element's Background-Color a Little Darker Using CSS

Dynamically change color to lighter or darker by percentage CSS

All modern browsers have had 100% filter support since January 2020. Even UC Browser for Android (instead of Chrome, on the $80 phones) supports it.

a {
    /* a nice, modern blue for links */
    color: #118bee;
}
a:active {
    /* Darken on click by 15% (down to 85%) */
    filter: brightness(0.85);
}

Additionally, you can control this dynamically with CSS variables, which have been supported by most browsers since October 2017 (excluding QQ):

:root {
    --color: #118bee;
    --hover-brightness: 1.2;
}
a {
    color: var(--color);
}
a:active {
    /* Darken on click */
    filter: brightness(var(--hover-brightness));
}

Not my project, but one that's great to look at for a real-world example of how great modern CSS can be, check out: MVP.css

Original Answer

If you're using a stack which lets you use Sass or Less, you can use the lighten function:

$linkcolour: #0000FF;

a {
  color: $linkcolour;
}

a.lighter {
  color: lighten($linkcolour, 50%);
}

There's also darken which does the same, but in the opposite direction.

How to darken a background using CSS?

Just add this code to your image css

 body{
 background:
        /* top, transparent black, faked with gradient */ 
        linear-gradient(
          rgba(0, 0, 0, 0.7), 
          rgba(0, 0, 0, 0.7)
        ),
        /* bottom, image */
        url(https://images.unsplash.com/photo-1614030424754-24d0eebd46b2);
    }

CSS Darken on Hover without Changing Text Color

Instead of using filter: Brightness(), I prefer to use filter: Saturate().
It gives object darken background but doesn't affect your text.

.badge {
  display: inline-block;
  padding: 0.35em 0.65em;
  font-size: 0.75em;
  font-weight: 700;
  line-height: 1;
  color: white;
  text-align: center;
  white-space: nowrap;
  vertical-align: baseline;
  border-radius: 0.25rem;
  text-decoration: none;
}
/* .badge:hover {filter: brightness(0.8);} */
.badge:hover {filter: saturate(0.5);}
.badge > span {color: white;}

<a href="#" class="badge" style="background-color: #0072CE;"><span>Some Text</span></a>

Darken CSS background image?

You can use the CSS3 Linear Gradient property along with your background-image like this:

#landing-wrapper {
    display:table;
    width:100%;
    background: linear-gradient( rgba(0, 0, 0, 0.5), rgba(0, 0, 0, 0.5) ), url('landingpagepic.jpg');
    background-position:center top;
    height:350px;
}

Here's a demo:

#landing-wrapper {  display: table;  width: 100%;  background: linear-gradient(rgba(0, 0, 0, 0.5), rgba(0, 0, 0, 0.5)), url('http://placehold.it/350x150');  background-position: center top;  height: 350px;  color: white;}

<div id="landing-wrapper">Lorem ipsum dolor ismet.</div>

CSS background image make darker

I would go for photoshop to blur the background or give it an overlay. However you can try giving it a linear gradient on your top-container class before the url call on the background-image as so:

background: linear-gradient( rgba(0,0,0,0.5), rgba(0, 0, 0, 0.5) ),url(../images/background1.jpg) no-repeat center center fixed;

just change the rgba value to what you need. Hope this helps.

Sample Image

How to darken a CSS background image?

#home {
   background: linear-gradient( rgba(0, 0, 0, 0.5), rgba(0, 0, 0, 0.5) ), url('file:///Volumes/Animus/Jon/Dropbox/website/hellcity.jpg');
  -webkit-background-size: cover;
  -moz-background-size:  cover;
  -o-background-size: cover;
  background-size: cover;
}

This should work