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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: #f5f5f5;
    color: #333;
}

.container {
    display: flex;
    flex-direction: column;
    height: 100vh;
}

header {
    background-color: #2c3e50;
    color: white;
    padding: 20px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}

header h1 {
    margin-bottom: 15px;
    font-size: 24px;
}

.controls {
    display: flex;
    gap: 10px;
}

#urlInput {
    flex: 1;
    padding: 10px 15px;
    border: none;
    border-radius: 4px;
    font-size: 14px;
}

#loadBtn {
    padding: 10px 30px;
    background-color: #3498db;
    color: white;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-size: 14px;
    font-weight: bold;
    transition: background-color 0.3s;
}

#loadBtn:hover {
    background-color: #2980b9;
}

main {
    flex: 1;
    overflow-y: auto;
    padding: 20px;
}

#viewer {
    background-color: white;
    border-radius: 4px;
    padding: 20px;
    box-shadow: 0 1px 3px rgba(0,0,0,0.1);
    height: 100%;
    overflow-y: auto;
}

.loading, .error {
    text-align: center;
    padding: 40px 20px;
    font-size: 16px;
}

.loading {
    color: #3498db;
}

.error {
    color: #e74c3c;
    background-color: #fadbd8;
    border-left: 4px solid #e74c3c;
    padding: 15px;
    border-radius: 4px;
}

footer {
    background-color: #ecf0f1;
    padding: 15px 20px;
    border-top: 1px solid #bdc3c7;
    text-align: center;
}

#pageInfo {
    font-size: 14px;
    color: #555;
}

@media (max-width: 768px) {
    .controls {
        flex-direction: column;
    }

    header h1 {
        font-size: 18px;
    }
}