{
box-sizing: border-box;
}

body {
margin: 0;
font-family: Arial, sans-serif;
color: #164b5f;
background: linear-gradient(#45c7f5, #d8f7ff, #7dcc55);
min-height: 100vh;
}

header {
text-align: center;
padding: 40px 20px;
background: rgba(255, 255, 255, 0.7);
border-bottom: 3px solid white;
}

header h1 {
margin: 0;
font-size: 45px;
color: #0878b5;
}

header p {
font-size: 20px;
}

main {
width: 90%;
max-width: 900px;
margin: 30px auto;
}

.presentation {
background: white;
padding: 25px;
border-radius: 25px;
border: 3px solid #63c9ed;
box-shadow: 0 5px 15px rgba(0, 100, 150, 0.2);
}

h2 {
color: #0785bd;
}

.projets {
margin-top: 30px;
}

.carte {
background: white;
padding: 25px;
border-radius: 25px;
border: 3px solid #63c9ed;
box-shadow: 0 5px 15px rgba(0, 100, 150, 0.2);
}

.carte h3 {
color: #159447;
}

.carte a {
display: inline-block;
padding: 12px 20px;
margin-top: 10px;
background: #19a9df;
color: white;
text-decoration: none;
font-weight: bold;
border-radius: 20px;
}

.carte a {
background: #0785bd;
}

footer {
text-align: center;
margin-top: 50px;
padding: 20px;
background: rgba(255, 255, 255, 0.7);
border-top: 3px solid white;
}

@media screen and (max-width: 600px) {

header h1 {
    font-size: 32px;
}

header p {
    font-size: 17px;
}

main {
    width: 95%;
}

}