/* CSS Reset and Variables */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

:root {
    --color-primary: #2563eb;
    --color-primary-hover: #1d4ed8;
    --color-primary-light: #dbeafe;
    --color-secondary: #64748b;
    --color-secondary-hover: #475569;
    --color-success: #10b981;
    --color-danger: #ef4444;
    --color-warning: #f59e0b;

    --color-bg: #f8fafc;
    --color-bg-panel: #ffffff;
    --color-text: #1e293b;
    --color-text-secondary: #64748b;
    --color-border: #e2e8f0;
    --color-border-hover: #cbd5e1;

    --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);

    --radius-sm: 6px;
    --radius-md: 8px;
    --radius-lg: 12px;

    --font-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    --font-mono: 'SF Mono', Monaco, 'Cascadia Code', 'Roboto Mono', Consolas, monospace;

    --transition-fast: 150ms ease;
    --transition-normal: 200ms ease;
}

html {
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-sans);
    background-color: var(--color-bg);
    color: var(--color-text);
    line-height: 1.6;
    min-height: 100vh;
}

/* App Container */
.app-container {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Header */
.header {
    background: linear-gradient(135deg, var(--color-primary) 0%, #7c3aed 100%);
    color: white;
    padding: 2rem;
    text-align: center;
}

.logo {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.75rem;
    margin-bottom: 0.5rem;
}

.logo-icon {
    width: 2.5rem;
    height: 2.5rem;
}

.logo h1 {
    font-size: 1.75rem;
    font-weight: 700;
    letter-spacing: -0.025em;
}

.tagline {
    font-size: 1rem;
    opacity: 0.9;
}

/* Main Content */
.main-content {
    flex: 1;
    display: grid;
    grid-template-columns: 1fr 1fr;
    grid-template-rows: auto auto 1fr;
    gap: 1.5rem;
    padding: 1.5rem;
    max-width: 1400px;
    margin: 0 auto;
    width: 100%;
}

/* Panels */
.panel {
    background: var(--color-bg-panel);
    border-radius: var(--radius-lg);
    padding: 1.5rem;
    box-shadow: var(--shadow-md);
    border: 1px solid var(--color-border);
}

.panel h2 {
    font-size: 1.125rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--color-text);
}

.panel-description {
    font-size: 0.875rem;
    color: var(--color-text-secondary);
    margin-bottom: 0.75rem;
}

/* Templates Panel */
.templates-panel {
    grid-row: span 2;
}

.search-box {
    position: relative;
    margin-bottom: 1rem;
}

.search-box input {
    width: 100%;
    padding: 0.75rem 1rem 0.75rem 2.75rem;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    font-size: 0.9375rem;
    transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.search-box input:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px var(--color-primary-light);
}

.search-icon {
    position: absolute;
    left: 0.875rem;
    top: 50%;
    transform: translateY(-50%);
    width: 1.125rem;
    height: 1.125rem;
    color: var(--color-text-secondary);
}

/* Template Categories */
.template-categories {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-bottom: 1rem;
}

.category-btn {
    padding: 0.375rem 0.875rem;
    border: 1px solid var(--color-border);
    border-radius: 9999px;
    background: var(--color-bg);
    color: var(--color-text-secondary);
    font-size: 0.8125rem;
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.category-btn:hover {
    border-color: var(--color-border-hover);
    color: var(--color-text);
}

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

/* Template List */
.template-list {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
    gap: 0.5rem;
    max-height: 400px;
    overflow-y: auto;
    padding-right: 0.5rem;
}

.template-list::-webkit-scrollbar {
    width: 6px;
}

.template-list::-webkit-scrollbar-track {
    background: var(--color-bg);
    border-radius: 3px;
}

.template-list::-webkit-scrollbar-thumb {
    background: var(--color-border-hover);
    border-radius: 3px;
}

.template-item {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.625rem 0.75rem;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    background: var(--color-bg);
    cursor: pointer;
    transition: all var(--transition-fast);
    font-size: 0.875rem;
}

.template-item:hover {
    border-color: var(--color-primary);
    background: var(--color-primary-light);
}

.template-item.selected {
    border-color: var(--color-primary);
    background: var(--color-primary);
    color: white;
}

.template-item .check-icon {
    width: 1rem;
    height: 1rem;
    opacity: 0;
    transition: opacity var(--transition-fast);
}

.template-item.selected .check-icon {
    opacity: 1;
}

/* Selected Templates Panel */
.selected-panel {
    display: flex;
    flex-direction: column;
}

.selected-templates {
    flex: 1;
    display: flex;
    flex-wrap: wrap;
    align-content: flex-start;
    gap: 0.5rem;
    margin-bottom: 1rem;
    min-height: 80px;
}

.empty-message {
    color: var(--color-text-secondary);
    font-size: 0.875rem;
    font-style: italic;
}

.selected-tag {
    display: inline-flex;
    align-items: center;
    gap: 0.375rem;
    padding: 0.375rem 0.625rem;
    background: var(--color-primary-light);
    color: var(--color-primary);
    border-radius: var(--radius-sm);
    font-size: 0.8125rem;
    font-weight: 500;
}

.selected-tag .remove-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 1.125rem;
    height: 1.125rem;
    border: none;
    background: transparent;
    color: var(--color-primary);
    cursor: pointer;
    border-radius: 50%;
    transition: all var(--transition-fast);
}

.selected-tag .remove-btn:hover {
    background: var(--color-primary);
    color: white;
}

.selected-tag .remove-btn svg {
    width: 0.75rem;
    height: 0.75rem;
}

/* Custom Rules Panel */
.custom-panel textarea {
    width: 100%;
    min-height: 120px;
    padding: 0.75rem;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    font-family: var(--font-mono);
    font-size: 0.875rem;
    line-height: 1.5;
    resize: vertical;
    transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.custom-panel textarea:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px var(--color-primary-light);
}

/* Preview Panel */
.preview-panel {
    grid-column: span 2;
    display: flex;
    flex-direction: column;
}

.preview-actions {
    display: flex;
    gap: 0.75rem;
    margin-bottom: 1rem;
}

.preview-content {
    flex: 1;
    padding: 1rem;
    background: #1e293b;
    color: #e2e8f0;
    border-radius: var(--radius-md);
    font-family: var(--font-mono);
    font-size: 0.8125rem;
    line-height: 1.6;
    overflow: auto;
    white-space: pre-wrap;
    word-break: break-word;
    min-height: 200px;
    max-height: 400px;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.625rem 1.25rem;
    border: none;
    border-radius: var(--radius-md);
    font-size: 0.9375rem;
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.btn svg {
    width: 1.125rem;
    height: 1.125rem;
}

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

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

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

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

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

.btn-icon:hover {
    background: var(--color-border);
    color: var(--color-text);
}

/* Footer */
.footer {
    padding: 1.5rem;
    text-align: center;
    background: var(--color-bg-panel);
    border-top: 1px solid var(--color-border);
}

.footer p {
    font-size: 0.875rem;
    color: var(--color-text-secondary);
}

.footer a {
    color: var(--color-primary);
    text-decoration: none;
    font-weight: 500;
    transition: color var(--transition-fast);
}

.footer a:hover {
    color: var(--color-primary-hover);
    text-decoration: underline;
}

/* Toast Notification */
.toast {
    position: fixed;
    bottom: 2rem;
    left: 50%;
    transform: translateX(-50%) translateY(100px);
    padding: 0.875rem 1.5rem;
    background: #1e293b;
    color: white;
    border-radius: var(--radius-md);
    font-size: 0.9375rem;
    font-weight: 500;
    box-shadow: var(--shadow-lg);
    opacity: 0;
    transition: all 0.3s ease;
    z-index: 1000;
}

.toast.show {
    transform: translateX(-50%) translateY(0);
    opacity: 1;
}

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

.toast.error {
    background: var(--color-danger);
}

/* Responsive Design */
@media (max-width: 1024px) {
    .main-content {
        grid-template-columns: 1fr;
        grid-template-rows: auto;
    }

    .templates-panel {
        grid-row: auto;
    }

    .preview-panel {
        grid-column: 1;
    }

    .template-list {
        max-height: 300px;
    }
}

@media (max-width: 768px) {
    .header {
        padding: 1.5rem 1rem;
    }

    .logo h1 {
        font-size: 1.5rem;
    }

    .logo-icon {
        width: 2rem;
        height: 2rem;
    }

    .main-content {
        padding: 1rem;
        gap: 1rem;
    }

    .panel {
        padding: 1rem;
    }

    .preview-actions {
        flex-direction: column;
    }

    .btn {
        justify-content: center;
    }

    .template-list {
        grid-template-columns: repeat(auto-fill, minmax(120px, 1fr));
    }
}

@media (max-width: 480px) {
    .header {
        padding: 1rem;
    }

    .logo {
        flex-direction: column;
        gap: 0.5rem;
    }

    .logo h1 {
        font-size: 1.25rem;
    }

    .tagline {
        font-size: 0.875rem;
    }

    .template-categories {
        justify-content: center;
    }

    .template-list {
        grid-template-columns: 1fr 1fr;
        max-height: 250px;
    }

    .preview-content {
        font-size: 0.75rem;
        min-height: 150px;
    }
}

/* Accessibility */
@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

/* Focus states */
:focus-visible {
    outline: 2px solid var(--color-primary);
    outline-offset: 2px;
}

button:focus:not(:focus-visible) {
    outline: none;
}