*{
    margin:0;
    padding:0;
    box-sizing:border-box;
}

body{
    font-family:Arial, sans-serif;
    background:#1a1a1a;
    color:#ffd700;
    min-height:100vh;
}

header{
    background:#2a2a2a;
    padding:15px;
    text-align:center;
    border-bottom:3px solid #ffd700;
}

header p{
    color:#cccccc;
}

nav{
    background:#333;
    text-align:center;
    padding:10px;
}

nav a{
    color:#ffd700;
    text-decoration:none;
    margin:5px;
    padding:8px 15px;
    border-radius:5px;
    display:inline-block;
}

nav a:hover,
nav a.active{
    background:#ffd700;
    color:#000;
}

.container{
    display:flex;
}

aside{
    width:200px;
    background:#2a2a2a;
    padding:15px;
}

aside h3{
    margin-bottom:10px;
}

aside ul{
    list-style:none;
}

aside li{
    margin:10px 0;
    padding:10px;
    background:#1a1a1a;
    border-left:3px solid #ffd700;
}

aside a{
    color:#ffd700;
    text-decoration:none;
}

main{
    flex:1;
    padding:20px;
}

section{
    background:#2a2a2a;
    padding:20px;
    margin-bottom:20px;
    border-left:4px solid #ffd700;
    border-radius:5px;
}

h2, h3{
    margin-bottom:10px;
}

p{
    margin-bottom:10px;
}

button{
    background:#ffd700;
    color:#000;
    border:none;
    padding:10px 15px;
    margin-top:10px;
    border-radius:5px;
    cursor:pointer;
    font-weight:bold;
}

button:hover{
    background:#ffea5c;
}

input{
    padding:10px;
    margin:5px 0;
    border:1px solid #ffd700;
    border-radius:5px;
    background:#333;
    color:#ffd700;
    display:block;
}

ul{
    margin-top:10px;
}

img{
    max-width:200px;
    display:block;
    margin-top:10px;
    border:3px solid #ffd700;
}

.output-box{
    margin-top:15px;
    background:#333;
    padding:15px;
    border-radius:5px;
}

footer{
    background:#2a2a2a;
    text-align:center;
    padding:10px;
    border-top:3px solid #ffd700;
}

body.dark-mode{
    background:#f5f5f5;
    color:#333;
}

body.dark-mode header{
    background:#ffffff;
    border-bottom:3px solid #333;
}

body.dark-mode header h1{
    color:#333;
}

body.dark-mode header p{
    color:#666;
}

body.dark-mode nav{
    background:#e0e0e0;
}

body.dark-mode nav a{
    color:#333;
}

body.dark-mode nav a:hover,
body.dark-mode nav a.active{
    background:#333;
    color:#fff;
}

body.dark-mode aside{
    background:#ffffff;
    border-right:1px solid #ddd;
}

body.dark-mode aside h3{
    color:#333;
}

body.dark-mode aside li{
    background:#f0f0f0;
    border-left:3px solid #333;
}

body.dark-mode aside a{
    color:#333;
}

body.dark-mode section{
    background:#ffffff;
    border-left:4px solid #333;
    color:#333;
}

body.dark-mode h2,
body.dark-mode h3{
    color:#333;
}

body.dark-mode p{
    color:#555;
}

body.dark-mode button{
    background:#333;
    color:#fff;
}

body.dark-mode button:hover{
    background:#555;
}

body.dark-mode input{
    border:1px solid #333;
    background:#fff;
    color:#333;
}

body.dark-mode .output-box{
    background:#f0f0f0;
    color:#333;
}

body.dark-mode .output-box span{
    color:#000;
    font-weight:bold;
}

body.dark-mode footer{
    background:#ffffff;
    border-top:3px solid #333;
}

body.dark-mode footer p{
    color:#333;
}

body.dark-mode img{
    border:3px solid #333;
}

@media screen and (max-width:768px){
    .container{
        flex-direction:column;
    }
    aside{
        width:100%;
    }
    input{
        width:100%;
    }
    button{
        width:100%;
    }
}