*{
    margin:0;
    padding:0;
    box-sizing:border-box;
    font-family:Arial, Helvetica, sans-serif;
}

body{
    background:#f4f4f4;
    color:#333;
    transition:.3s;
}

header{
    background:#222;
    color:white;
    position:sticky;
    top:0;
    z-index:100;
}

nav{
    display:flex;
    justify-content:space-between;
    align-items:center;
    padding:15px 8%;
}

.logo{
    color:#00bcd4;
}

.nav-links{
    display:flex;
    list-style:none;
}

.nav-links li{
    margin-left:20px;
}

.nav-links a{
    color:white;
    text-decoration:none;
}

.nav-links a:hover{
    color:#00bcd4;
}

#themeBtn{
    padding:8px 12px;
    border:none;
    cursor:pointer;
    border-radius:5px;
}

.hero{
    display:flex;
    justify-content:space-around;
    align-items:center;
    padding:80px 8%;
    flex-wrap:wrap;
}

.hero-text h1{
    font-size:45px;
}

.hero-text span{
    color:#00bcd4;
}

.hero-text p{
    margin:20px 0;
}

.hero-text button{
    padding:12px 25px;
    border:none;
    background:#00bcd4;
    color:white;
    cursor:pointer;
    border-radius:5px;
}

.hero-image img{
    width:260px;
    border-radius:50%;
    box-shadow:0 0 20px rgba(0,0,0,.2);
}

section{
    padding:60px 8%;
}

h2{
    text-align:center;
    margin-bottom:30px;
}

.cards{
    display:grid;
    grid-template-columns:repeat(auto-fit,minmax(150px,1fr));
    gap:20px;
}

.card{
    background:white;
    padding:25px;
    text-align:center;
    border-radius:10px;
    box-shadow:0 0 10px rgba(0,0,0,.1);
}

.project-container{
    display:grid;
    grid-template-columns:repeat(auto-fit,minmax(250px,1fr));
    gap:20px;
}

.project{
    background:white;
    padding:20px;
    border-radius:10px;
    box-shadow:0 0 10px rgba(0,0,0,.1);
}

form{
    max-width:600px;
    margin:auto;
}

form input,
form textarea{
    width:100%;
    padding:12px;
    margin-bottom:15px;
}

form button{
    width:100%;
    padding:12px;
    background:#00bcd4;
    color:white;
    border:none;
    cursor:pointer;
}

footer{
    background:#222;
    color:white;
    text-align:center;
    padding:20px;
}

.dark-mode{
    background:#1b1b1b;
    color:white;
}

.dark-mode .card,
.dark-mode .project{
    background:#333;
    color:white;
}

.dark-mode input,
.dark-mode textarea{
    background:#444;
    color:white;
}

@media(max-width:768px){

.hero{
    flex-direction:column;
    text-align:center;
}

.hero-image{
    margin-top:30px;
}

nav{
    flex-direction:column;
}

.nav-links{
    margin:15px 0;
    flex-wrap:wrap;
    justify-content:center;
}

.back-btn{
    display:block;
    width:fit-content;
    text-align:center;
    margin:20px auto;
    padding:14px 28px;
    text-decoration:none;
    color:rgb(0, 0, 0);
    border:2px solid rgb(0, 0, 0);
    border-radius:8px;
    font-weight:600;
    transition:.3s;
}

.back-btn:hover{
    background:rgb(0, 0, 0);
    color:#050816;
    transform:translateY(-5px);
}

.back-btn h2{
    font-size:18px;
}