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

:root {
    --primary-color: #6366f1;
    --primary-hover: #4f46e5;
    --secondary-color: #64748b;
    --success-color: #10b981;
    --danger-color: #ef4444;
    --background: #0f172a;
    --surface: #1e293b;
    --surface-light: #334155;
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --border-color: #475569;
    --accent-gradient: linear-gradient(135deg, #6366f1 0%, #8b5cf6 100%);
    --item-colors: #f472b6, #fb923c, #facc15, #4ade80, #22d3ee, #a78bfa, #f87171, #38bdf8;
    --border-radius: 8px;
    --transition: all 0.2s ease;
}

html {
    font-size: 16px;
}

body {
    font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
    background: var(--background);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Header Styles */
.header {
    background: var(--surface);
    border-bottom: 1px solid var(--border-color);
    padding: 1.5rem;
    text-align: center;
}

.header-content {
    max-width: 1400px;
    margin: 0 auto;
}

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

.logo-image {
    width: 40px;
    height: 40px;
    border-radius: 8px;
}

.logo h1 {
    font-size: 1.75rem;
    font-weight: 700;
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.tagline {
    color: var(--text-secondary);
    font-size: 0.95rem;
}

/* Main Container */
.main-container {
    flex: 1;
    display: grid;
    grid-template-columns: 320px 1fr 320px;
    grid-template-rows: 1fr auto;
    gap: 1.5rem;
    padding: 1.5rem;
    max-width: 1600px;
    margin: 0 auto;
    width: 100%;
}

/* Panel Styles */
.controls-panel,
.preview-panel,
.code-panel,
.examples-panel {
    background: var(--surface);
    border-radius: var(--border-radius);
    border: 1px solid var(--border-color);
    overflow: hidden;
}

.controls-panel {
    grid-row: span 2;
    padding: 1.25rem;
    overflow-y: auto;
    max-height: calc(100vh - 180px);
}

.preview-panel {
    display: flex;
    flex-direction: column;
}

.code-panel {
    grid-column: 3;
}

.examples-panel {
    grid-column: 2 / 4;
    padding: 1.25rem;
}

.panel-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 1.25rem;
    border-bottom: 1px solid var(--border-color);
    background: var(--surface-light);
}

.controls-panel .panel-header {
    margin: -1.25rem -1.25rem 1rem -1.25rem;
    padding: 1rem 1.25rem;
}

.controls-panel .panel-header:not(:first-child) {
    margin-top: 1.5rem;
}

.panel-header h2 {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-primary);
}

/* Control Groups */
.control-group {
    margin-bottom: 1rem;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    position: relative;
}

.control-group label {
    font-size: 0.85rem;
    color: var(--text-secondary);
    font-family: 'Consolas', 'Monaco', monospace;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.control-group select,
.control-group input[type="text"] {
    width: 100%;
    padding: 0.625rem 0.875rem;
    background: var(--background);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    color: var(--text-primary);
    font-size: 0.9rem;
    transition: var(--transition);
    cursor: pointer;
}

.control-group select:hover,
.control-group input:hover {
    border-color: var(--primary-color);
}

.control-group select:focus,
.control-group input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.2);
}

.property-info {
    position: absolute;
    right: 0;
    top: 0;
    width: 18px;
    height: 18px;
    background: var(--surface-light);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.7rem;
    color: var(--text-secondary);
    cursor: help;
    transition: var(--transition);
}

.property-info:hover {
    background: var(--primary-color);
    color: white;
}

/* Range Input Styles */
.range-container {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.range-container input[type="range"] {
    flex: 1;
    -webkit-appearance: none;
    appearance: none;
    height: 6px;
    background: var(--background);
    border-radius: 3px;
    cursor: pointer;
}

.range-container input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 18px;
    height: 18px;
    background: var(--primary-color);
    border-radius: 50%;
    cursor: pointer;
    transition: var(--transition);
}

.range-container input[type="range"]::-webkit-slider-thumb:hover {
    transform: scale(1.2);
    background: var(--primary-hover);
}

.range-container input[type="range"]::-moz-range-thumb {
    width: 18px;
    height: 18px;
    background: var(--primary-color);
    border: none;
    border-radius: 50%;
    cursor: pointer;
}

.range-value {
    min-width: 45px;
    text-align: right;
    font-family: 'Consolas', 'Monaco', monospace;
    font-size: 0.85rem;
    color: var(--primary-color);
}

/* Button Styles */
.btn {
    padding: 0.625rem 1rem;
    border: none;
    border-radius: var(--border-radius);
    font-size: 0.875rem;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
}

.btn-add {
    background: var(--success-color);
    color: white;
    flex: 1;
}

.btn-add:hover {
    background: #059669;
}

.btn-remove {
    background: var(--danger-color);
    color: white;
    flex: 1;
}

.btn-remove:hover {
    background: #dc2626;
}

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

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

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

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

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

.reset-btn {
    padding: 0.375rem 0.75rem;
    background: transparent;
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    color: var(--text-secondary);
    font-size: 0.75rem;
    cursor: pointer;
    transition: var(--transition);
}

.reset-btn:hover {
    border-color: var(--danger-color);
    color: var(--danger-color);
}

.items-controls {
    display: flex;
    gap: 0.75rem;
    margin-bottom: 1rem;
}

.selected-item-info {
    padding: 0.75rem;
    background: var(--background);
    border-radius: var(--border-radius);
    margin-bottom: 1rem;
    text-align: center;
}

.selected-item-info p {
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.selected-item-info p.has-selection {
    color: var(--primary-color);
    font-weight: 500;
}

/* Preview Panel */
.preview-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 1.25rem;
    border-bottom: 1px solid var(--border-color);
    background: var(--surface-light);
}

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

.flex-container {
    flex: 1;
    display: flex;
    min-height: 350px;
    margin: 1.25rem;
    padding: 1rem;
    background: var(--background);
    border: 2px dashed var(--border-color);
    border-radius: var(--border-radius);
    position: relative;
    gap: 10px;
    transition: var(--transition);
}

.flex-container.show-axes::before,
.flex-container.show-axes::after {
    content: '';
    position: absolute;
    pointer-events: none;
}

.flex-container.show-axes::before {
    top: 50%;
    left: 0;
    right: 0;
    height: 2px;
    background: linear-gradient(90deg, transparent 0%, #ef4444 10%, #ef4444 90%, transparent 100%);
    opacity: 0.5;
}

.flex-container.show-axes::after {
    left: 50%;
    top: 0;
    bottom: 0;
    width: 2px;
    background: linear-gradient(180deg, transparent 0%, #3b82f6 10%, #3b82f6 90%, transparent 100%);
    opacity: 0.5;
}

.flex-container.show-axes.column-direction::before {
    background: linear-gradient(90deg, transparent 0%, #3b82f6 10%, #3b82f6 90%, transparent 100%);
}

.flex-container.show-axes.column-direction::after {
    background: linear-gradient(180deg, transparent 0%, #ef4444 10%, #ef4444 90%, transparent 100%);
}

.axis-legend {
    display: flex;
    justify-content: center;
    gap: 2rem;
    padding: 0.75rem;
    font-size: 0.8rem;
}

.legend-main {
    color: #ef4444;
}

.legend-cross {
    color: #3b82f6;
}

/* Flex Items */
.flex-item {
    min-width: 60px;
    min-height: 60px;
    padding: 1rem;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.25rem;
    font-weight: 700;
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: var(--transition);
    position: relative;
    color: var(--background);
}

.flex-item:nth-child(8n+1) { background: #f472b6; }
.flex-item:nth-child(8n+2) { background: #fb923c; }
.flex-item:nth-child(8n+3) { background: #facc15; }
.flex-item:nth-child(8n+4) { background: #4ade80; }
.flex-item:nth-child(8n+5) { background: #22d3ee; }
.flex-item:nth-child(8n+6) { background: #a78bfa; }
.flex-item:nth-child(8n+7) { background: #f87171; }
.flex-item:nth-child(8n+8) { background: #38bdf8; }

.flex-item:hover {
    transform: scale(1.05);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
}

.flex-item.selected {
    outline: 3px solid var(--text-primary);
    outline-offset: 2px;
    transform: scale(1.05);
}

/* Code Panel */
.code-output {
    margin: 0;
    padding: 1.25rem;
    background: var(--background);
    font-family: 'Consolas', 'Monaco', 'Courier New', monospace;
    font-size: 0.85rem;
    line-height: 1.7;
    overflow-x: auto;
    height: calc(100% - 57px);
}

.code-output code {
    color: var(--text-primary);
}

.code-output .property {
    color: #93c5fd;
}

.code-output .value {
    color: #fcd34d;
}

.code-output .selector {
    color: #f472b6;
}

.code-output .bracket {
    color: var(--text-secondary);
}

/* Examples Panel */
.examples-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
    gap: 0.75rem;
}

.example-btn {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.5rem;
    padding: 1rem;
    background: var(--background);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    color: var(--text-primary);
    cursor: pointer;
    transition: var(--transition);
}

.example-btn:hover {
    border-color: var(--primary-color);
    background: var(--surface-light);
}

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

.example-name {
    font-size: 0.8rem;
    color: var(--text-secondary);
}

/* Footer */
.footer {
    background: var(--surface);
    border-top: 1px solid var(--border-color);
    padding: 1.25rem;
    text-align: center;
}

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

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

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

/* Toast Notification */
.toast {
    position: fixed;
    bottom: 2rem;
    left: 50%;
    transform: translateX(-50%) translateY(100px);
    background: var(--surface);
    color: var(--text-primary);
    padding: 1rem 1.5rem;
    border-radius: var(--border-radius);
    border: 1px solid var(--success-color);
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.4);
    opacity: 0;
    transition: all 0.3s ease;
    z-index: 1000;
}

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

/* Scrollbar Styles */
::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}

::-webkit-scrollbar-track {
    background: var(--background);
}

::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--secondary-color);
}

/* Responsive Design */
@media (max-width: 1200px) {
    .main-container {
        grid-template-columns: 280px 1fr;
        grid-template-rows: auto auto auto;
    }

    .controls-panel {
        grid-row: span 1;
    }

    .code-panel {
        grid-column: 1 / 3;
    }

    .examples-panel {
        grid-column: 1 / 3;
    }
}

@media (max-width: 900px) {
    .main-container {
        grid-template-columns: 1fr;
        padding: 1rem;
        gap: 1rem;
    }

    .controls-panel {
        max-height: none;
        order: 2;
    }

    .preview-panel {
        order: 1;
    }

    .code-panel {
        grid-column: 1;
        order: 3;
    }

    .examples-panel {
        grid-column: 1;
        order: 4;
    }

    .flex-container {
        min-height: 280px;
    }
}

@media (max-width: 600px) {
    .header {
        padding: 1rem;
    }

    .logo h1 {
        font-size: 1.4rem;
    }

    .tagline {
        font-size: 0.85rem;
    }

    .panel-header {
        padding: 0.875rem 1rem;
    }

    .panel-header h2 {
        font-size: 0.9rem;
    }

    .controls-panel {
        padding: 1rem;
    }

    .examples-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .flex-item {
        min-width: 45px;
        min-height: 45px;
        font-size: 1rem;
    }

    .items-controls {
        flex-direction: column;
    }

    .btn {
        width: 100%;
    }
}

/* Print Styles */
@media print {
    .controls-panel,
    .examples-panel,
    .footer {
        display: none;
    }

    .main-container {
        display: block;
    }

    .preview-panel,
    .code-panel {
        page-break-inside: avoid;
    }
}