* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

body {
    background-color: #f5f5f5;
    color: #333;
    line-height: 1.6;
    padding: 20px;
}

.container {
    max-width: 800px;
    margin: 0 auto;
    background-color: #fff;
    padding: 30px;
    border-radius: 10px;
    box-shadow: 0 0 20px rgba(0, 0, 0, 0.1);
    position: relative;
}

.main-nav {
    position: absolute;
    top: 20px;
    left: 20px;
}

.nav-home {
    color: #3498db;
    text-decoration: none;
    font-weight: 600;
    font-size: 15px;
    padding: 5px 10px;
    border-radius: 4px;
    transition: all 0.2s;
}

.nav-home:hover {
    background-color: #f0f7fd;
}

.app-header {
    text-align: center;
    margin: 30px 0 20px;
    padding-top: 10px;
}

h1 {
    margin-bottom: 10px;
    color: #2c3e50;
}

p {
    color: #7f8c8d;
}

.input-group {
    display: flex;
    gap: 10px;
    margin-bottom: 20px;
    flex-wrap: wrap;
}

.input-group input {
    flex: 1;
    min-width: 200px;
    padding: 12px;
    border: 1px solid #ddd;
    border-radius: 5px;
    font-size: 16px;
}

.input-group button {
    padding: 12px 20px;
    background-color: #3498db;
    color: white;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    font-size: 16px;
    transition: background-color 0.3s;
}

.input-group button:hover {
    background-color: #2980b9;
}

.input-group button:disabled {
    background-color: #95a5a6;
    cursor: not-allowed;
}

#clear-btn {
    background-color: #e74c3c;
}

#clear-btn:hover {
    background-color: #c0392b;
}

.options {
    display: flex;
    gap: 20px;
    margin-bottom: 20px;
    flex-wrap: wrap;
}

.option {
    display: flex;
    align-items: center;
    gap: 10px;
}

.option label {
    font-weight: 500;
}

.option select, .option input {
    padding: 8px;
    border: 1px solid #ddd;
    border-radius: 5px;
}

#qr-code {
    display: flex;
    justify-content: center;
    margin: 30px 0;
    min-height: 200px;
}

.error-message {
    color: #e74c3c;
    text-align: center;
    margin-top: 10px;
    font-weight: 500;
    min-height: 24px;
}

.ad-container {
    margin: 30px 0;
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
    border: 1px solid #eaeaea;
}

.ad-top {
    margin-top: 0;
}

.ad-bottom {
    margin-bottom: 10px;
}

.ad-label {
    background-color: #f8f9fa;
    color: #7f8c8d;
    font-size: 12px;
    text-align: center;
    padding: 6px;
    text-transform: uppercase;
    letter-spacing: 1px;
    border-bottom: 1px solid #eaeaea;
}

@media (max-width: 768px) {
    .container {
        padding: 20px;
    }
    
    .main-nav {
        position: static;
        text-align: center;
        margin-bottom: 15px;
    }
    
    .app-header {
        margin-top: 10px;
    }
    
    .ad-container {
        margin: 20px 0;
    }
    
    .input-group {
        flex-direction: column;
    }
    
    .input-group input, .input-group button {
        width: 100%;
    }
    
    .options {
        flex-direction: column;
        gap: 10px;
    }
}