different padding on sides on a viewport below 768px - html

Question

I am making a website with block elements. When I go below 768 px the elements will have a border around them The padding on each side of the block elements is different. I need the sites to have the same padding on 5px. I tried to solve that with adding the code:
#media only screen and (max-width: 768px) {
.row {
margin-left: -5px;
margin-right: -5px;
}
.row>[class*="col-"] {
padding-left: 5px;
padding-right: 5px;
}
}
But does not solve the problem. Does anybody have an idea how I can solve this? (When i paste in my HTML code in the Stackoverflow editor the div tags is jumping around. Sorry for this, I do not know why. So the html code looks quite messy)
/* Card and Button */
.index-content a:hover {
color: black;
text-decoration: none;
}
.index-content {
/*margin-bottom: 20px;*/
/*padding: 50px 0px;*/
}
.index-content .row {
margin-top: 20px;
}
.index-content a {
color: black;
}
.index-content .card {
background-color: #FFFFFF;
padding: 0;
-webkit-border-radius: 4px;
-moz-border-radius: 4px;
border-radius: 4px;
box-shadow: 0 4px 5px 0 rgba(0, 0, 0, 0.14), 0 1px 10px 0 rgba(0, 0, 0, 0.12), 0 2px 4px -1px rgba(0, 0, 0, 0.3);
}
.index-content .card:hover {
box-shadow: 0 16px 24px 2px rgba(0, 0, 0, 0.14), 0 6px 30px 5px rgba(0, 0, 0, 0.12), 0 8px 10px -5px rgba(0, 0, 0, 0.3);
color: black;
}
.index-content .card img {
width: 100%;
border-top-left-radius: 4px;
border-top-right-radius: 4px;
height: 350px;
}
.index-content .card h4 {
margin: 20px;
}
.index-content .card p {
margin: 20px;
opacity: 0.65;
}
.index-content .blue-button {
width: 100px;
-webkit-transition: background-color 1s, color 1s;
/* For Safari 3.1 to 6.0 */
transition: background-color 1s, color 1s;
min-height: 20px;
background-color: #002E5B;
color: #ffffff;
border-radius: 4px;
text-align: center;
font-weight: lighter;
margin: 0px 20px 15px 20px;
padding: 5px 0px;
display: inline-block;
}
.index-content .blue-button:hover {
background-color: #dadada;
color: #002E5B;
}
#media (max-width: 768px) {
.index-content .col-lg-4 {
margin-top: 20px;
}
}
#media (min-width: 768px) {
.card {
position: relative;
}
.card-content {
position: absolute;
bottom: 0;
width: 100%;
background: rgba(0, 0, 0, 0.5);
}
.card-content h4,
.card-content p {
color: white;
width: 100%;
float: left;
margin: 0 0 5px;
}
.card-content a {
float: right;
}
.index-content .card h4,
.index-content .card p {
padding: 15px 20px;
margin: 0;
}
.index-content .card p {
padding: 0 20px 15px;
margin: 0;
}
}
/* GRID ELEMENTS */
/* Set width between block elements */
.small-padding.top {
padding-top: 10px;
}
.small-padding.bottom {
padding-bottom: 10px;
}
.small-padding.left {
padding-left: 5px;
}
.small-padding.right {
padding-right: 5px;
}
/* Media quries */
#media only screen and (max-width: 768px) {
.small-padding.bottom {
padding-bottom: 10px;
}
}
#media only screen and (max-width: 768px) {
.row {
margin-left: -7.5px;
margin-right: -7.5px;
}
.row>[class*="col-"] {
padding-left: 7.5px;
padding-right: 7.5px;
}
}
<div class="row">
<div class="index-content">
<div class="container">
<a href="#">
<div class="col-sm-12 small-padding bottom">
<div class="card">
<img src="https://image.ibb.co/nJ97Go/bmw.jpg"></img>
<div class="card-content">
<h4>BMW NEW MODELS</h4>
<p>Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.</p>
Read More
</div>
</div>
</div>
</a>
</div>
</div>
</div>
<div class="row">
<div class="index-content">
<div class="container">
<div class="col-sm-4 small-padding right bottom">
<div class="card">
<img src="https://image.ibb.co/iiWA2T/bmw_1.jpg"></img>
<div class="card-content">
<h4>BMW NEW MODELS</h4>
Read More
</div>
</div>
</div>
<div class="col-sm-8 small-padding left">
<div class="card">
<img src="https://image.ibb.co/nJ97Go/bmw.jpg"></img>
<div class="card-content">
<h4>BMW NEW MODELS</h4>
<!-- <p>Brødtekst</p> -->
Read More
</div>
</div>
</div>
</div>
</div>
</div>

Answer 1

Why aren' you using Bootstrap grid classes? Then no custom CSS is required.
<div class="col-sm-12 col-md-12 col-xs-12">
</div>

Answer 2

You must use bootstrap classes for all screen sizes if you use class="col-sm-8" only is apply to medium screens, the correct use is:
<div class="col-lg-8 col-md-8 col-sm-8 col-xs-12">
</div>

Answer 3

JUST ADD !important if you want to apply the same padding.
#media only screen and (max-width: 768px) {
.row {
margin-left: -5px !important;
margin-right: -5px !important;
}
.row>[class*="col-"] {
padding-left: 5px !important;
padding-right: 5px !important;
}
}

Answer 4

.row>[class*="col-"] is looking for any class="col- in the directly child of .row, your HTML is not structured like this. So remove the >
.row [class*="col-"] {
padding-left: 5px;
padding-right: 5px;
}
Or you also can set .container [class*="col-"]