body { 
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif; 
    line-height: 1.6; 
    margin: 0; 
    background-color: #f4f7f6; 
    color: #333; }
.container { 
    width: 80%; 
    margin: auto; 
    overflow: hidden; 
    padding: 20px; }
header { 
    background: #35424a; 
    color: #ffffff; 
    padding-top: 30px; 
    min-height: 70px; 
    border-bottom: #e8491d 3px solid; 
    text-align: center; }
header h1 { 
    margin: 0; 
    padding-bottom: 20px; }
nav { 
    background: #e8491d; 
    color: #fff; 
    padding: 10px 0; 
    text-align: center; }
nav a { 
    color: #fff; 
    text-decoration: none; 
    font-weight: bold; 
    font-size: 16px; 
    padding: 10px 20px; 
    display: inline-block; 
    transition: background 0.3s; }
nav a:hover { 
    background: #35424a; 
    border-radius: 5px; }
.content { 
    background: #fff; 
    padding: 20px; 
    margin-top: 20px; 
    border-radius: 8px; 
    box-shadow: 0 0 10px rgba(0,0,0,0.05); 
    min-height: 300px; }
footer { 
    margin-top: 30px; 
    text-align: center; 
    padding: 15px; 
    background: #35424a; 
    color: white; }
input[type="number"], input[type="text"] { 
    padding: 10px; 
    margin-right: 10px; 
    border-radius: 4px; 
    border: 1px solid #ccc; 
    width: 200px; }
button { 
    padding: 10px 15px; 
    background: #e8491d; 
    color: white; 
    border: none; 
    border-radius: 4px; 
    cursor: pointer; 
    font-size: 15px; 
    transition: background 0.3s; }
button:hover { 
    background: #35424a; }
hr { 
    border: 0; 
    height: 1px; 
    background: #eee; 
    margin: 20px 0; }
.hasil-box { 
    background: #e8faeb; 
    padding: 15px; 
    border-left: 5px solid #2ecc71; 
    border-radius: 4px; 
    margin-top: 15px; }