body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
    text-align: center;
    background-color: #0d1117;
    color: #c9d1d9;
}

h1 {
    font-size: 2rem;
    margin: 20px 0;
    color: #f0f6fc;
}

p {
    font-size: 1rem;
    margin: 10px 0;
    color: #c9d1d9;
}

input, button {
    margin: 10px 0;
    padding: 10px;
    font-size: 1rem;
    width: 90%;
    max-width: 400px;
    border-radius: 5px;
    box-sizing: border-box;
}

input {
    border: 1px solid #30363d;
    background-color: #0d1117;
    color: #c9d1d9;
    color-scheme: dark;
    transition: border-color 0.3s, box-shadow 0.3s;
}

input:focus {
    outline: none;
    border-color: #58a6ff;
    box-shadow: 0 0 0 3px rgba(88, 166, 255, 0.3);
}

button {
    background-color: #238636;
    color: white;
    border: none;
    cursor: pointer;
    transition: background-color 0.3s, box-shadow 0.3s;
}

button:hover {
    background-color: #2ea043;
    box-shadow: 0 0 20px rgba(35, 134, 54, 0.3);
}

#result {
    margin-top: 20px;
    padding: 10px;
    background-color: #161b22;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.8);
    border-radius: 8px;
    max-width: 90%;
    margin-left: auto;
    margin-right: auto;
    text-align: left;
    color: #c9d1d9;
}

.output {
    margin: 10px 0;
    font-weight: bold;
    font-size: 1rem;
    color: #f0f6fc;
}

/* Responsive cho màn hình nhỏ */
@media (max-width: 768px) {
    h1 {
        font-size: 1.5rem;
    }
    p {
        font-size: 0.9rem;
    }
    input, button {
        font-size: 0.9rem;
        padding: 8px;
    }
    .output {
        font-size: 0.9rem;
    }
}