Media queries' classes applying outside of context - css

Question

I have the following media queries:
#media only screen and (max-width : 320px){
.jumbotron-startup{
min-height: 100vh;
height: auto;
}
.jumbotron-slide-2 p, .jumbotron-slide-2 h2{
display: none;
}
.startup-card{
height: auto;
background-color: inherit;
}
}
#media only screen and (min-width : 321px){
.jumbotron-startup{
min-height: 130vh;
height: auto;
}
.jumbotron-slide-2 p, .jumbotron-slide-2 h2{
display: none;
}
.startup-card{
height: auto;
background-color: inherit;
}
.sh-portrait{
display: inline-block;
}
#yes-startup{
margin-bottom: 10px;
}
}
#media only screen and (min-device-width : 320px) and (max-device-width : 480px) {
.jumbotron-what-is-switchhon{
min-height: 100vh;
height: auto;
}
.space-top{
margin-top: 0;
}
.jumbotron-what-is-switchhon p{
font-size: 1.2em;
text-align: center !important;
}
.jumbotron-startup img{
height: 64px;
}
.jumbotron-startup p{
font-size: 1.1em;
}
}
For some reason, these media queries, some of their classes are applying to the page on any environment, that means even if the resolution is 1920x1080 from my current monitor in my desktop computer.
I have no idea why this is happening, as it has never happened before. Anyone has any idea as to why they are acting out of context?
Outside of the media queries I'll just put some of the classes I have that for some reason, they are being overwritten:
.startup-card{
background-color: rgba(255, 255, 255, 0.6);
color: #333;
height: 300px;
border-radius: 5px;
}
.startup-card h2{
padding-top: 20px;
}
.startup-card p{
padding: 10px;
text-align: left;
font-size: 1.1em;
}
.startup-card img{
padding-top: 20px;
width: auto;
height: 90px;
}
Just to make sure we're on the same page, these media queries are at the bottom of my stylesheet, like many experts recommend, since sometimes funny things may happen if put somewhere else other than on the bottom.
EDIT
Here's a PEN for you to take a look at it. http://codepen.io/yisera/pen/xdGKh
*****UPDATE******
After commenting the media queries to see where the problem is, I found that all media queries work correctly except this one:
#media only screen and (min-width : 321px){
.jumbotron-startup{
min-height: 130vh;
height: auto;
}
.jumbotron-slide-2 p, .jumbotron-slide-2 h2{
display: none;
}
.startup-card{
height: auto;
background-color: inherit;
}
.sh-portrait{
display: inline-block;
}
#yes-startup{
margin-bottom: 10px;
}
}
I can't figure out why, it has the correct syntax and everything, everything closes correctly, it's driving me nuts

Answer 1

Move all your media queries at the bottom of your CSS. Otherwise the styles you have written inside the media queries will overwritten with the normal styles.
EDIT:
As OP asked in chat, "Do you know how can I elaborate a media query to target just the landscape of a mobile phone?"
/* #### Mobile Phones Portrait #### */
#media screen and (max-device-width: 480px) and (orientation: portrait){
/* some CSS here */
}
/* #### Mobile Phones Landscape #### */
#media screen and (max-device-width: 640px) and (orientation: landscape){
/* some CSS here */
}
/* #### Mobile Phones Portrait or Landscape #### */
#media screen and (max-device-width: 640px){
/* some CSS here */
}
/* #### iPhone 4+ Portrait or Landscape #### */
#media screen and (max-device-width: 480px) and (-webkit-min-device-pixel-ratio: 2){
/* some CSS here */
}
/* #### Tablets Portrait or Landscape #### */
#media screen and (min-device-width: 768px) and (max-device-width: 1024px){
/* some CSS here */
}