body {
    margin: 0;
    font-family: Arial, Helvetica, sans-serif;
    background-color: #f4f6f8;
    color: #222;
}

.wrapper {
    max-width: 950px;
    margin: 40px auto;
    padding: 30px;
}

h1 {
    color: #26394f;
    text-align: center;
    margin-bottom: 30px;
}

.api-card {
    background-color: #ffffff;
    margin-bottom: 28px;
    padding: 25px;
    border-radius: 12px;
    box-shadow: 0 4px 14px rgba(0, 0, 0, 0.12);
}

h2 {
    color: #34495e;
    border-bottom: 2px solid #dfe6ee;
    padding-bottom: 6px;
}

h3 {
    color: #26394f;
}

p {
    line-height: 1.6;
}

a {
    color: #1d5fa7;
    font-weight: bold;
}

a:hover {
    color: #0f3f73;
}

.demo-box {
    margin-top: 18px;
    padding: 18px;
    background-color: #eef3f8;
    border-left: 5px solid #34495e;
    border-radius: 8px;
}

button {
    padding: 10px 16px;
    background-color: #34495e;
    color: #ffffff;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    font-weight: bold;
}

button:hover {
    background-color: #26394f;
}

.back-btn {
    display: inline-block;
    margin-bottom: 25px;
    padding: 10px 16px;
    background-color: #34495e;
    color: #ffffff;
    text-decoration: none;
    border-radius: 8px;
    font-weight: bold;
    transition: background-color 0.3s ease;
}

.back-btn:hover {
    background-color: #26394f;
}

.output {
    margin-top: 15px;
    padding: 12px;
    background-color: #ffffff;
    border-radius: 8px;
}

.output img {
    max-width: 100%;
    border-radius: 8px;
    margin-top: 10px;
}

.book-item {
    margin-bottom: 14px;
    padding-bottom: 10px;
    border-bottom: 1px solid #dfe6ee;
}

@media (max-width: 700px) {
    .wrapper {
        margin: 20px;
        padding: 0;
    }

    .api-card {
        padding: 20px;
    }
}