/* CSS Variables for Light/Dark Mode */
:root {
    /* Light mode colors */
    --bg-primary: #ffffff;
    --bg-secondary: #f8fafc;
    --bg-tertiary: #f1f5f9;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --text-muted: #94a3b8;
    --border-color: #e2e8f0;
    --border-hover: #cbd5e1;
    
    /* Accent colors */
    --accent-primary: #3b82f6;
    --accent-secondary: #8b5cf6;
    --accent-success: #10b981;
    --accent-warning: #f59e0b;
    --accent-error: #ef4444;
    
    /* Gradients */
    --primary-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --secondary-gradient: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
    --success-gradient: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
    
    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 10px 10px -5px rgb(0 0 0 / 0.04);
    
    /* QR Code specific colors */
    --qr-foreground: #000000;
    --qr-background: #ffffff;
    --qr-border: #e2e8f0;
}

[data-theme="dark"] {
    /* Dark mode colors */
    --bg-primary: #0f172a;
    --bg-secondary: #1e293b;
    --bg-tertiary: #334155;
    --text-primary: #f8fafc;
    --text-secondary: #cbd5e1;
    --text-muted: #64748b;
    --border-color: #475569;
    --border-hover: #64748b;
    
    /* Dark mode shadows */
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.3), 0 2px 4px -2px rgb(0 0 0 / 0.3);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.3), 0 4px 6px -4px rgb(0 0 0 / 0.3);
    --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.3), 0 10px 10px -5px rgb(0 0 0 / 0.2);
    
    /* Dark mode QR colors */
    --qr-foreground: #ffffff;
    --qr-background: #000000;
    --qr-border: #475569;
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    transition: background-color 0.3s ease, color 0.3s ease;
}

html {
    width: 100%;
    height: 100%;
}

/* Top Navigation */
.top-nav {
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
    padding: 1rem 0;
    width: 100%;
    position: relative;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
}

.nav-home {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    text-decoration: none;
    color: var(--text-primary);
    font-weight: 600;
    font-size: 1.1rem;
    transition: color 0.3s ease;
}

.nav-home:hover {
    color: var(--accent-primary);
}

.nav-icon {
    font-size: 1.5rem;
}

.nav-breadcrumb {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.theme-toggle {
    background: rgba(59, 130, 246, 0.1);
    border: 1px solid rgba(59, 130, 246, 0.2);
    border-radius: 50%;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all 0.3s ease;
    margin-left: auto;
}

.theme-toggle:hover {
    background: rgba(59, 130, 246, 0.2);
    transform: scale(1.1);
}

.theme-icon {
    font-size: 1.2rem;
    filter: drop-shadow(0 1px 2px rgba(0, 0, 0, 0.2));
}

/* App Container */
.app-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
    width: 100%;
}

/* Header */
.app-header {
    background: var(--primary-gradient);
    color: white;
    padding: 2rem;
    border-radius: 16px;
    margin: 2rem 0;
    text-align: center;
    position: relative;
    overflow: hidden;
    box-shadow: var(--shadow-lg);
}

.app-header::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: radial-gradient(circle at 20% 80%, rgba(120, 119, 198, 0.3) 0%, transparent 50%);
}

.app-header::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: radial-gradient(circle at 80% 20%, rgba(255, 119, 198, 0.3) 0%, transparent 50%);
}

.header-icons {
    display: flex;
    justify-content: center;
    gap: 1rem;
    margin-bottom: 1rem;
}

.header-icon {
    font-size: 2rem;
    animation: float 3s ease-in-out infinite;
    filter: drop-shadow(0 2px 4px rgba(0, 0, 0, 0.2));
}

.header-icon:nth-child(2) {
    animation-delay: 1.5s;
}

@keyframes float {
    0%, 100% { transform: translateY(0px); }
    50% { transform: translateY(-10px); }
}

.app-header h1 {
    font-size: 2.5rem;
    font-weight: 800;
    margin-bottom: 0.5rem;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
}

.app-header p {
    font-size: 1.1rem;
    opacity: 0.9;
    font-weight: 400;
}

/* Main Content */
.main-content {
    display: flex;
    flex-direction: column;
    gap: 2rem;
    margin-bottom: 2rem;
}

/* Input Section */
.input-section {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 1.5rem;
    box-shadow: var(--shadow-sm);
}

.input-section h3 {
    margin-bottom: 1rem;
    color: var(--text-primary);
    font-size: 1.25rem;
    font-weight: 600;
}

.input-tabs {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 1.5rem;
    flex-wrap: wrap;
}

.input-tab {
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 0.5rem 1rem;
    cursor: pointer;
    transition: all 0.3s ease;
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-secondary);
}

.input-tab:hover {
    background: var(--border-color);
    border-color: var(--border-hover);
}

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

.input-content {
    display: none;
}

.input-content.active {
    display: block;
}

.input-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
    margin-bottom: 1rem;
}

/* Input Groups */
.input-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    width: 100%;
}

.input-group label {
    font-weight: 500;
    color: var(--text-primary);
    font-size: 0.9rem;
}

.input-group input,
.input-group textarea,
.input-group select {
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    background: var(--bg-primary);
    color: var(--text-primary);
    font-size: 1rem;
    transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.input-group input:focus,
.input-group textarea:focus,
.input-group select:focus {
    outline: none;
    border-color: var(--accent-primary);
    box-shadow: 0 0 0 3px rgb(59 130 246 / 0.1);
}

.input-hint {
    font-size: 0.8rem;
    color: var(--text-muted);
    font-style: italic;
    margin-top: -0.25rem;
}

.input-group textarea {
    resize: vertical;
    min-height: 80px;
}

.checkbox-text {
    margin-left: 0.5rem;
    font-size: 0.9rem;
    color: var(--text-secondary);
}

/* QR Display Section */
.qr-display-section {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 1.5rem;
    text-align: center;
    box-shadow: var(--shadow-sm);
}

.qr-display-section h3 {
    margin-bottom: 1rem;
    color: var(--text-primary);
    font-size: 1.25rem;
    font-weight: 600;
}

.qr-container {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 300px;
    margin-bottom: 1.5rem;
}

.qr-placeholder {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1rem;
    color: var(--text-muted);
}

.placeholder-icon {
    font-size: 4rem;
    opacity: 0.5;
}

.qr-placeholder p {
    font-size: 1rem;
    max-width: 300px;
    text-align: center;
}

#qrCanvas {
    border: 2px solid var(--qr-border);
    border-radius: 8px;
    box-shadow: var(--shadow-md);
}

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

.download-btn,
.share-btn {
    background: var(--primary-gradient);
    color: white;
    border: none;
    border-radius: 8px;
    padding: 0.75rem 1.5rem;
    cursor: pointer;
    font-weight: 600;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    box-shadow: var(--shadow-md);
}

.download-btn:hover,
.share-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn-icon {
    font-size: 1.1rem;
}

/* Customization Section */
.customization-section {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 1.5rem;
    box-shadow: var(--shadow-sm);
}

.customization-section h3 {
    margin-bottom: 1.5rem;
    color: var(--text-primary);
    font-size: 1.25rem;
    font-weight: 600;
}

.options-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1.5rem;
    margin-bottom: 2rem;
}

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

.option-group label {
    font-weight: 500;
    color: var(--text-primary);
    font-size: 0.9rem;
}

.option-group input[type="range"] {
    width: 100%;
    height: 6px;
    border-radius: 3px;
    background: var(--border-color);
    outline: none;
    -webkit-appearance: none;
    appearance: none;
}

.option-group input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: var(--primary-gradient);
    cursor: pointer;
    box-shadow: var(--shadow-md);
}

.option-group input[type="range"]::-moz-range-thumb {
    appearance: none;
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: var(--primary-gradient);
    cursor: pointer;
    box-shadow: var(--shadow-md);
    border: none;
}

.option-group input[type="color"] {
    width: 100%;
    height: 40px;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    cursor: pointer;
}

.option-group select {
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    background: var(--bg-primary);
    color: var(--text-primary);
    font-size: 0.9rem;
    cursor: pointer;
}

.option-value {
    font-size: 0.9rem;
    color: var(--text-secondary);
    text-align: center;
    font-weight: 500;
}

.generate-section {
    text-align: center;
}

.generate-btn {
    background: var(--success-gradient);
    color: white;
    border: none;
    border-radius: 12px;
    padding: 1rem 2rem;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    display: inline-flex;
    align-items: center;
    gap: 0.75rem;
    box-shadow: var(--shadow-md);
}

.generate-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.generate-btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
    transform: none;
}

.btn-spinner {
    animation: spin 1s linear infinite;
}

@keyframes spin {
    from { transform: rotate(0deg); }
    to { transform: rotate(360deg); }
}

/* History Section */
.history-section {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 1.5rem;
    box-shadow: var(--shadow-sm);
}

.history-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
}

.history-header h3 {
    color: var(--text-primary);
    font-size: 1.25rem;
    font-weight: 600;
}

.clear-btn {
    background: var(--accent-error);
    color: white;
    border: none;
    border-radius: 6px;
    padding: 0.5rem 1rem;
    cursor: pointer;
    font-size: 0.9rem;
    transition: all 0.3s ease;
}

.clear-btn:hover {
    background: #dc2626;
    transform: translateY(-1px);
}

.qr-history {
    min-height: 100px;
}

.no-history {
    text-align: center;
    color: var(--text-muted);
    font-style: italic;
}

.qr-history-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 1rem;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    margin-bottom: 0.5rem;
    background: var(--bg-primary);
    transition: all 0.3s ease;
}

.qr-history-item:hover {
    border-color: var(--border-hover);
    box-shadow: var(--shadow-sm);
}

.qr-history-content {
    display: flex;
    align-items: center;
    gap: 1rem;
    flex: 1;
}

.qr-history-thumbnail {
    width: 40px;
    height: 40px;
    border: 1px solid var(--border-color);
    border-radius: 4px;
}

.qr-history-text {
    flex: 1;
}

.qr-history-title {
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.25rem;
}

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

.qr-history-actions {
    display: flex;
    gap: 0.5rem;
}

.qr-history-actions button {
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    padding: 0.5rem;
    cursor: pointer;
    transition: all 0.3s ease;
    font-size: 1rem;
}

.qr-history-actions button:hover {
    background: var(--border-color);
    transform: scale(1.1);
}

/* Tips Section */
.tips-section {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 1.5rem;
    box-shadow: var(--shadow-sm);
}

.tips-section h3 {
    margin-bottom: 1.5rem;
    color: var(--text-primary);
    font-size: 1.25rem;
    font-weight: 600;
}

.tips-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1rem;
}

.tip-item {
    display: flex;
    align-items: flex-start;
    gap: 0.75rem;
    padding: 1rem;
    background: var(--bg-primary);
    border-radius: 8px;
    border: 1px solid var(--border-color);
}

.tip-icon {
    font-size: 1.5rem;
    flex-shrink: 0;
}

.tip-item p {
    color: var(--text-secondary);
    font-size: 0.9rem;
    line-height: 1.5;
}

/* Footer */
.app-footer {
    text-align: center;
    padding: 2rem 0;
    color: var(--text-secondary);
    border-top: 1px solid var(--border-color);
    margin-top: 2rem;
}

/* Responsive Design */
@media (max-width: 768px) {
    .app-header {
        padding: 1.5rem;
        margin: 1rem 0;
    }
    
    .app-header h1 {
        font-size: 2rem;
    }
    
    .input-tabs {
        justify-content: center;
    }
    
    .input-row {
        grid-template-columns: 1fr;
    }
    
    .options-grid {
        grid-template-columns: 1fr;
    }
    
    .qr-actions {
        flex-direction: column;
        align-items: center;
    }
    
    .download-btn,
    .share-btn {
        width: 100%;
        max-width: 300px;
        justify-content: center;
    }
    
    .tips-grid {
        grid-template-columns: 1fr;
    }
    
    .nav-container {
        flex-direction: column;
        gap: 1rem;
        text-align: center;
    }
    
    .theme-toggle {
        margin: 0;
    }
}

@media (max-width: 480px) {
    .app-container {
        padding: 0 0.5rem;
    }
    
    .input-section,
    .qr-display-section,
    .customization-section,
    .history-section,
    .tips-section {
        padding: 1rem;
    }
    
    .app-header {
        padding: 1rem;
    }
    
    .app-header h1 {
        font-size: 1.75rem;
    }
    
    .generate-btn {
        padding: 0.875rem 1.5rem;
        font-size: 1rem;
    }
    
    .qr-container {
        min-height: 250px;
    }
    
    .placeholder-icon {
        font-size: 3rem;
    }
}

/* Notification Styles */
.notification {
    position: fixed;
    top: 20px;
    right: 20px;
    padding: 1rem 1.5rem;
    border-radius: 8px;
    color: white;
    font-weight: 600;
    z-index: 10000;
    transform: translateX(100%);
    transition: transform 0.3s ease;
    box-shadow: var(--shadow-lg);
}

.notification-success {
    background-color: var(--accent-success);
}

.notification-error {
    background-color: var(--accent-error);
}

.notification.show {
    transform: translateX(0);
}