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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    padding: 20px;
}

.container {
    max-width: 1000px;
    margin: 0 auto;
    background: white;
    border-radius: 12px;
    padding: 40px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
}

h1 {
    color: #333;
    margin-bottom: 10px;
    font-size: 2.5em;
}

.subtitle {
    color: #666;
    margin-bottom: 30px;
    font-size: 1.1em;
}

.generator-section {
    background: #f8f9fa;
    padding: 25px;
    border-radius: 8px;
    margin-bottom: 30px;
}

.input-group, .customization-group {
    margin-bottom: 20px;
}

.input-group label, .customization-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 600;
    color: #333;
}

textarea {
    width: 100%;
    padding: 12px;
    border: 2px solid #ddd;
    border-radius: 6px;
    font-size: 1em;
    resize: vertical;
    min-height: 100px;
    font-family: inherit;
}

textarea:focus {
    outline: none;
    border-color: #667eea;
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

#charCount {
    display: block;
    font-size: 0.9em;
    color: #666;
    margin-top: 5px;
}

.color-inputs {
    display: flex;
    gap: 20px;
    margin-bottom: 15px;
}

.color-inputs label {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 0;
}

input[type="color"] {
    width: 50px;
    height: 40px;
    border: none;
    border-radius: 4px;
    cursor: pointer;
}

input[type="text"] {
    width: 100%;
    padding: 10px;
    border: 2px solid #ddd;
    border-radius: 6px;
    margin-top: 8px;
}

.btn-primary {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border: none;
    padding: 12px 30px;
    font-size: 1em;
    border-radius: 6px;
    cursor: pointer;
    font-weight: 600;
    transition: transform 0.2s, box-shadow 0.2s;
    width: 100%;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 20px rgba(102, 126, 234, 0.3);
}

.btn-primary:active {
    transform: translateY(0);
}

.preview-section {
    margin-bottom: 30px;
}

.preview-section h2 {
    color: #333;
    margin-bottom: 15px;
}

.qr-preview {
    background: #f8f9fa;
    border: 2px dashed #ddd;
    border-radius: 8px;
    padding: 40px;
    text-align: center;
    min-height: 300px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.qr-preview canvas, .qr-preview img {
    max-width: 100%;
    max-height: 400px;
}

.placeholder {
    color: #999;
    font-size: 1.1em;
}

.export-options {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 10px;
    margin-top: 20px;
}

.btn-export {
    background: #28a745;
    color: white;
    border: none;
    padding: 10px 20px;
    border-radius: 6px;
    cursor: pointer;
    font-weight: 600;
    transition: background 0.2s;
}

.btn-export:hover {
    background: #218838;
}

.use-cases h2, .tips h2 {
    color: #333;
    margin-bottom: 20px;
    margin-top: 30px;
}

.case-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
    margin-bottom: 30px;
}

.case-card {
    background: #f8f9fa;
    padding: 20px;
    border-radius: 8px;
    border-left: 4px solid #667eea;
}

.case-card h3 {
    color: #333;
    margin-bottom: 10px;
}

.case-card p {
    color: #666;
    font-size: 0.95em;
}

.tips ul {
    list-style: none;
    background: #f8f9fa;
    padding: 20px;
    border-radius: 8px;
}

.tips li {
    padding: 10px 0;
    padding-left: 25px;
    position: relative;
    color: #555;
}

.tips li:before {
    content: "✓";
    position: absolute;
    left: 0;
    color: #667eea;
    font-weight: bold;
}