:root {
    --primary-color: #007bff;
    --primary-hover: #0056b3;
    --bg-color: #f4f6f8;
    --card-bg: #ffffff;
    --text-color: #333333;
    --text-secondary: #666666;
    --border-color: #e0e0e0;
    --radius: 8px;
    --shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
    --transition: all 0.3s ease;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
    padding: 20px;
}

.container {
    max-width: 1000px;
    margin: 0 auto;
}

.main-header {
    text-align: center;
    margin-bottom: 30px;
}

.main-header h1 {
    font-size: 2rem;
    color: var(--primary-color);
    margin-bottom: 10px;
}

.main-header p {
    color: var(--text-secondary);
}

.generator-wrapper {
    background: var(--card-bg);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    overflow: hidden;
}

/* Tabs */
.tabs-container {
    background: #f8f9fa;
    border-bottom: 1px solid var(--border-color);
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
}

.tabs {
    display: flex;
    white-space: nowrap;
    padding: 0 10px;
}

.tab-btn {
    background: none;
    border: none;
    padding: 15px 20px;
    font-size: 1rem;
    color: var(--text-secondary);
    cursor: pointer;
    transition: var(--transition);
    border-bottom: 3px solid transparent;
}

.tab-btn:hover {
    color: var(--primary-color);
}

.tab-btn.active {
    color: var(--primary-color);
    border-bottom-color: var(--primary-color);
    font-weight: 600;
}

/* Content Layout */
.content-wrapper {
    display: grid;
    grid-template-columns: 1fr 350px;
    gap: 30px;
    padding: 30px;
}

@media (max-width: 768px) {
    .content-wrapper {
        grid-template-columns: 1fr;
    }
}

/* Form Section */
.form-section {
    flex: 1;
}

.mode-content {
    display: none;
}

.mode-content.active {
    display: block;
    animation: fadeIn 0.3s ease;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(5px); }
    to { opacity: 1; transform: translateY(0); }
}

.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 500;
    color: var(--text-color);
}

.required {
    color: #dc3545;
}

input[type="text"],
input[type="url"],
input[type="tel"],
input[type="email"],
input[type="number"],
textarea,
select {
    width: 100%;
    padding: 12px;
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    font-size: 1rem;
    transition: var(--transition);
    background: #fff;
}

input:focus,
textarea:focus,
select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(0, 123, 255, 0.1);
}

textarea {
    resize: vertical;
}

/* Options Section */
.options-section {
    margin-top: 30px;
    padding-top: 20px;
    border-top: 1px solid var(--border-color);
}

.color-picker-group {
    display: flex;
    gap: 20px;
}

.color-picker-group label {
    display: flex;
    align-items: center;
    gap: 10px;
    cursor: pointer;
}

input[type="color"] {
    border: none;
    width: 40px;
    height: 40px;
    cursor: pointer;
    background: none;
}

/* Generate Button */
.generate-btn {
    display: block;
    width: 100%;
    padding: 15px;
    background-color: var(--primary-color);
    color: white;
    border: none;
    border-radius: var(--radius);
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    margin-top: 30px;
}

.generate-btn:hover {
    background-color: var(--primary-hover);
    transform: translateY(-1px);
}

.generate-btn:active {
    transform: translateY(1px);
}

/* Result Section */
.result-section {
    background: #f8f9fa;
    border-radius: var(--radius);
    padding: 20px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    min-height: 300px;
    border: 1px dashed var(--border-color);
}

.qr-preview {
    margin-bottom: 20px;
    text-align: center;
}

.qr-preview img {
    max-width: 100%;
    height: auto;
    box-shadow: var(--shadow);
    border-radius: 4px;
}

.placeholder {
    color: var(--text-secondary);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 10px;
}

.placeholder svg {
    color: #ccc;
}

.result-actions {
    text-align: center;
}

.tip {
    font-size: 0.9rem;
    color: var(--text-secondary);
}

.main-footer {
    text-align: center;
    margin-top: 40px;
    color: var(--text-secondary);
    font-size: 0.9rem;
}