* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

:root {
    --bg-color: #f9fafb;
    --text-color: #111827;
    --surface: #ffffff;
    --primary: #3b82f6;
    --primary-hover: #2563eb;
    --border: #e5e7eb;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --input-bg: #fff;
    --text-muted: #6b7280;
}

[data-theme='dark'] {
    --bg-color: #111827;
    --text-color: #f9fafb;
    --surface: #1f2937;
    --primary: #60a5fa;
    --primary-hover: #3b82f6;
    --border: #374151;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.5), 0 2px 4px -1px rgba(0, 0, 0, 0.3);
    --input-bg: #374151;
    --text-muted: #9ca3af;
}

body {
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
    transition: background-color 0.3s, color 0.3s;
}

header {
    background-color: var(--surface);
    border-bottom: 1px solid var(--border);
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    position: sticky;
    top: 0;
    z-index: 100;
}

.nav-controls {
    display: flex;
    gap: 1rem;
    align-items: center;
}

select {
    padding: 0.5rem;
    border-radius: 4px;
    border: 1px solid var(--border);
    background-color: var(--input-bg);
    color: var(--text-color);
    cursor: pointer;
}

.theme-toggle {
    background: none;
    border: 1px solid var(--border);
    border-radius: 4px;
    padding: 0.5rem 1rem;
    cursor: pointer;
    color: var(--text-color);
}

.container {
    max-width: 1200px;
    margin: 2rem auto;
    padding: 0 1rem;
}

.hero {
    text-align: center;
    margin-bottom: 3rem;
}

.hero h1 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    color: var(--text-color);
}

.hero p {
    color: var(--text-muted);
    font-size: 1.1rem;
    max-width: 600px;
    margin: 0 auto;
}

.generator-wrap {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 2rem;
    background-color: var(--surface);
    padding: 2rem;
    border-radius: 12px;
    box-shadow: var(--shadow);
}

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

.controls {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.tabs {
    display: flex;
    gap: 0.5rem;
    flex-wrap: wrap;
    border-bottom: 1px solid var(--border);
    padding-bottom: 1rem;
}

.tab {
    padding: 0.5rem 1rem;
    background: var(--input-bg);
    border: 1px solid var(--border);
    border-radius: 4px;
    cursor: pointer;
    color: var(--text-color);
    transition: all 0.2s;
}

.tab.active {
    background: var(--primary);
    color: white;
    border-color: var(--primary);
}

.input-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.input-panel {
    display: none;
    flex-direction: column;
    gap: 1rem;
}

.input-panel.active {
    display: flex;
}

label {
    font-weight: 600;
    font-size: 0.9rem;
}

input[type="text"], input[type="email"], input[type="url"], input[type="tel"], input[type="password"], textarea {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--border);
    border-radius: 8px;
    background-color: var(--input-bg);
    color: var(--text-color);
    font-size: 1rem;
}

input[type="color"] {
    width: 50px;
    height: 40px;
    padding: 0;
    border: none;
    cursor: pointer;
}

.options-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
}

.preview-area {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: flex-start;
    padding: 2rem;
    border: 1px dashed var(--border);
    border-radius: 12px;
    background-color: var(--bg-color);
    text-align: center;
}

#qrcode-canvas {
    background-color: white;
    padding: 10px;
    border-radius: 8px;
    box-shadow: var(--shadow);
    margin-bottom: 1.5rem;
    min-width: 200px;
    min-height: 200px;
}

.actions {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
    justify-content: center;
}

.btn {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    font-weight: 600;
    font-size: 1rem;
    transition: background 0.2s;
    background: var(--primary);
    color: white;
}

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

.btn-secondary {
    background: var(--input-bg);
    color: var(--text-color);
    border: 1px solid var(--border);
}

.btn-secondary:hover {
    background: var(--border);
}

.content-section {
    margin-top: 4rem;
    padding: 2rem;
    background: var(--surface);
    border-radius: 12px;
    box-shadow: var(--shadow);
}

.content-section h2 {
    margin-bottom: 1.5rem;
    font-size: 2rem;
}

.content-section h3 {
    margin: 1.5rem 0 0.5rem 0;
    font-size: 1.4rem;
}

.content-section p, .content-section ul {
    margin-bottom: 1rem;
    color: var(--text-muted);
}

.content-section ul {
    padding-left: 2rem;
}

.faq {
    margin-top: 2rem;
}

.faq-item {
    margin-bottom: 1.5rem;
    border-bottom: 1px solid var(--border);
    padding-bottom: 1rem;
}

.faq-item h4 {
    font-size: 1.2rem;
    margin-bottom: 0.5rem;
}

footer {
    text-align: center;
    padding: 2rem;
    margin-top: 4rem;
    border-top: 1px solid var(--border);
    color: var(--text-muted);
}

.error-msg {
    color: #ef4444;
    font-size: 0.85rem;
    margin-top: 0.25rem;
    display: none;
}